Br J: first published as 10.1136/hrt.37.5.548 on 1 May 1975. Downloaded from

British Heart Journal, 1975, 37, 548-560. Proceedings of the British Cardiac Society

THE AUTUMN MEETING of the British Cardiac Manchester on I7 April, and reported that preparations Society was held at the Royal College of Physicians, were well in hand. The Honorary Secretary added that, London, on Tuesday and Wednesday I9 and 20 Nov- because ofthe long delay involved in printing, the closing ember I974. The President, JOHN GOODWIN took the date for the submission of abstracts for the Manchester Chair at 9.oo a.m. during Private Business. At the meeting was I7 January. Scientific Session the Chair was taken by W. P. CLELAND. 4 The Autumn Meeting in 1975 would revert to a Thursday and Friday, 13 and I4 November. This year's Private Business meeting was on a Tuesday and Wednesday, and Council I The President reported the deaths of Cornelio Papp had agreed to send a referendum asking for members' and Douglas Robertson, and the members stood in opinions as to which days were most convenient. tribute. 5 The Annual General Meeting in I976 would be in Edinburgh on i April. 2 In the unavoidable absence of the Treasurer the President read his report, which was based on the un- 6 Edgar Sowton reported that the meeting with audited figures to the end of September 1974. the Swedish Society would be held on i and 2 Sep- The Society's finances were reasonably satisfactory. tember and the morning ofthe 3rd, in Stockholm. It was About two-thirds of the income from subscriptions was planned to hold symposia on the mornings of the ist spent on secretarial and clerical services, stationery, the and 2nd, with free communications on these two after- publication of the annual booklet, and miscellaneous noons. The closing date for submission of abstracts of general expenses; the remainder was split between sub- free communications was i8 April I975. On the Wednes- scriptions to other societies, a subsidy to the Thomas day morning the plan was to visit new hospitals and Lewis Lecture, and the cost of meetings. centres in Stockholm; a boat trip in the Stockholm Twenty-two people had received grants to attend the

archipelago was planned for the Wednesday afternoon. http://heart.bmj.com/ VII World Congress of Cardiology in Buenos Aires in Travel agents were still reluctant to give firm quotations, September I974 from funds made available by the but two package deals had been asked for - (i) for hotels British Heart Foundation, the British Council, and the and (2) for accommodation in University halls of resi- Society. dence, both to be for one week. There were no plans to increase members' subscrip- tions next year, but if inflation continued at its present 7 The Secretary reported that any inquiries regarding rate an increase soon after was unavoidable. the European Travelling Fellowships should be ad- The Treasurer was considering whether the direct dressed to Dr. Morris Butler at the British Heart debit system should replace bankers' orders for the pay- Foundation. ment of subscriptions. on September 27, 2021 by guest. Protected copyright. The Treasurer's report also stated that the Society of 8 The Specialist Advisory Committee on Cardio- Cardiological Technicians was now very active, was vascular Disease (one of several Advisory Committees recruiting new members, arranging scientific and social to the Joint Committee on Higher Medical Training of meetings, and taking its place in negotiations. They had the Royal Colleges of Physicians) was now engaged in asked whether it was possible for the British Cardiac visiting centres to look into the training programmes Society to increase the annual grant of £50. Council available for Senior Registrars, and where appropriate recommended a grant of CI50 this year, to help with Registrars. Some nine centres had been visited by teams their library project, and thereafter £iioo a year, and this of 3 people (one from the SAC who acted as Chairman, was approved. Council had also discussed the Tech- one from the SAC on General Internal Medicine, and nicians' suggestion that the Society might help in some one other who might or might not be a cardiologist). The way with the J7ournal of Cardiovascular Technology and reports sent back to the SAC and the JCHMT were had agreed that Somerville, Linden, and Towers should already proving of considerable value to the centres look into the possibility. The Cardiological Technicians visited. The second edition of the training programmes also asked if the British Cardiac Society would appoint a was being revised and would be available shortly. liaison officer to act with them, and Council suggested The turnover of members of the Specialist Advisory that the Honorary Assistant Secretary should take over Committee had proved too rapid and in future two this role. This was agreed. members would retire one year and one the next. In reply to a question from Whitaker, the President 3 Wade confirmed the invitation for the British Cardiac explained that the Department of Health would do Society to hold the Annual General Meeting in I975 in nothing about a request from a Region for a Senior Br Heart J: first published as 10.1136/hrt.37.5.548 on 1 May 1975. Downloaded from Proceedings of the British Cardiac Society 549

Registrar appointment until the relevant Specialist b) Semple reported that the Rehabilitation Working Advisory Committee had looked at the post, the training Party had held its last formal meeting. The report programme, and the centre, and reported to the Joint was still being independently checked and edited; Committee on Higher Medical Training. If the report this was primarily for general practitioners and were favourable the request would go to the DHSS, to family doctors, and publication and distribution the Central Manpower Committee, and to the Senior were being discussed with the Department of Registrar Sub-Committee, and if the DHSS agreed the Health. The report would probably be published in appointment would be allowed. the Journal of the Royal College of Physicians, and the College would ensure that members of the s The Joint Liaison Committee (British Cardiac Soc- British Cardiac Society would be sent copies. It iety and Royal College of Physicians/Department of would be some months before the report was ready. Health) had continued to meet and a short report on its c) Shaper reported that the Working Party on Pri- activities would be sent out soon. Members were in- mary Prevention of Cardiac Disease was attempt- vited to submit problems of any sort connected with ing to provide general practitioners and physicians cardiology, including buildings. It was hoped to modify with the best possible advice which could be given the Committee's activities slightly, and instead of regu- at present on this subject, and was now working lar meetings it was decided to hold special meetings for on the final recommendations for completion by major topics for which the DHSS had promised to the spring or early summer of 1975. It was hoped mobilize the necessary people for the particular prob- to produce a small cheap booklet which would lem. Wade suggested that too little was known of this reach every practitioner in the U.K. committee and that a circular should be sent to all mem- d) Fleming reported that a good deal of information bers outlining its role and perhaps suggesting the type had been collected on the prophylaxis of infective of problem which it could discuss. The President replied endocarditis. He requested that basic case details that he would prepare a short report and circulate it in of proven Strep. viridans endocarditis, especially in the near future to all members. regard to previous dental work, should be sent to him and he thanked members for their co-opera- IO Because some ofthe recommendations in the Report tion so far. He also suggested that the topic might on Coronary Arteriography by the Cardiology Com- be discussed by the Society at the meeting in Man- mittee of the Royal College of Physicians had been ques- chester next April. tioned by members, Emanuel suggested that there might be a place for an editorial in the Journal outlining the 13 The President announced that Council had ap- problem. Goodwin thanked Emanuel for the consider- pointed Linden as the new Editor of Cardiovascular able amount of work involved in preparing the report. Research, and thanked Shillingford, on behalf of the Society, for his foresight and imagination in starting this http://heart.bmj.com/ iI The President reported briefly on the VII World Journal, and for setting and maintaining the high level of Congress of Cardiology held in Buenos Aires in Sep- contribution, which had established the intemational tember I974: a short report was being prepared for pub- standing of Cardiovascular Research. lication in due course. The VIII World Congress would be held in Tokyo in I978. 14 The Research Group had held a The President also reported that the question of the very successful meeting on Monday i8 December, and merger of the International Society of Cardiology (the Council had agreed in principle to a joint half- or scientific body dealing with Scientific Councils, World quarter-day with the Society next Autumn. Congresses, etc.) and the International Cardiological on September 27, 2021 by guest. Protected copyright. Foundation (the fund-raising body) had been discussed The Society dined together at the Zoological Gardens at length by the Assembly meeting in Buenos Aires, and Restaurant with John Goodwin in the Chair. The guests it was agreed by 37 to 5 that the merger should take included Mr. Harry Moore, Dr. Dennis Beddard, Dr. place. This was subject to the agreement of the ICF who Stuart Reid, and Dr. E. Varnauskas. were meeting at the beginning of December. If the merger were rejected by the ICF then the American Heart Association would probably withdraw its support and the ISC would collapse. The British Cardiac Society Scientific Communications was committed to nothing if the merger did not go through; if it did go through an increase in the Society's present subscription was agreed in principle, but no Borderline hypertension - a specific entity? figure had been recommended or agreed. Lyle Petersen had been elected President of the ISC, and John Good- J. B. Irving, H. Brash, F. Kerr (all introduced), and win President-Elect, to take office in 1976. Brian J. Kirby Royal Devon and Exeter Hospital, Exeter EX2 sDW 12 Brief reports were given on the Working Parties: a) Lawson McDonald reported that the final edition The concept of borderline or labile hypertension as an of the report on Acute Coronary Care would be early stage in the natural history of essential hyperten- completed by the end of the year. sion has attracted much interest, mainly on account of Br Heart J: first published as 10.1136/hrt.37.5.548 on 1 May 1975. Downloaded from 55o Proceedings of the British Cardiac Society its therapeutic implications. Several studies have Observations on the origin of the impedance demonstrated that this group of patients is character- cardiogram ized by pronounced lability of pressure and raised cardiac output at rest. We have investigated 32 indi- A. Harley viduals (8 normal subjects, I4 patients with borderline Regional Cardiac Centre, Sefton General Hospital, hypertension and IO patients with established hyper- Liverpool Li5 2HE tension) by 24-hour monitoring of intra-arterial blood pressure using a radiotelemetry system and by haemo- Although they are quantitatively related to systemic dynamic studies during treadmill exercise. stroke volume and pulse pressure, it has not yet been Variability of blood pressure was measured by several established how the variations in thoracic impedance methods including range of values, standard deviation, originate during the cardiac cycle. Experimental work and an analysis of variance. No significant differences has suggested that pulmonary blood volume changes among the three groups were found. account for most of the systolic portion of the signal. To The resting cardiac indices were: established group test this hypothesis, impedance cardiograms were re- 2.54 1 min - 1 - 2, borderline group 3.2 1 min-1 m- 2 and corded from I4 patients before and 6 months after sur- normal 3.4 1 min- 1 m -2. The only significant difference gical closure of atrial septal defects (mean Qp/Qs= in the various haemodynamic parameters was the resting 2.7±0.3). Resting , and the amplitude (Dz) heart rate (P < O.OI). The response to exercise was simi- and maximum first derivative (dz/dt) of the impedance lar in all three groups except that patients with estab- cardiogram were not significantly changed. Individual lished hypertension had a steeper rise in blood pressure. pre- and postoperative values correlated significantly. In There is little evidence from these studies to suggest contrast Dz and dz/dt were increased in patients with that patients with labile hypertension are a specific aortic incompetence. Comparison of impedance cardio- group. grams in atrioventricular dissociation with sinus rhythm showed that the initial presystolic deflection was assoc- iated with atrial activity. Transient occlusion of the decreased Dz and dz/dt propor- tionally to reduced stroke volume but produced no wave- Observations on the aetiology of unexplained or form change. It is concluded that the impedance cardio- primary pulmonary hypertension gram is sensitive to changes in left ventricular stroke volume but insensitive to changes in right ventricular Geoffrey Wade and D. P. Atukorale (introduced) stroke volume, and that local venous pressure changes The Royal Infirmary, Manchester MI3 9WL do not contribute significantly, even to the diastolic

part of the impedance cardiogram signal. http://heart.bmj.com/ Forty-four patients with 'primary' or 'unexplained' pulmonary hypertension have been analysed in relation to their aetiology. Intermediate coronary care - a controlled trial In 3 cases the disease followed clinical pulmonary P. C. embolization and in 3 more there were congenital Reynell abnormalities of the pulmonary vessels with abnormal Bradford Royal Infirmary, Bradford BD9 6RJ broncho-pulmonary communications which we thought A controlled trial of intermediate coronary care was were causal. These patients differed in age and sex carried out over a five year period at a district general preponderance and natural history from the remaining hospital. One thousand consecutive male patients under on September 27, 2021 by guest. Protected copyright. 38. 65 surviving to leave the Coronary Care Unit (CCU) The 38 conformed to the picture of primary pul- were allocated at random into an intermediate care group monary hypertension presented in published reports: 33 kept in the same ward as the CCU and a control group were female, with an average age of 33 years; i8 had discharged to a general medical ward. The intermediate borne children, and in 6 the onset of the disease related care patients were nursed by the trained CCU staff, to childbirth. The course was usually short with an resuscitation equipment was immediately available, and average survival time from the onset of symptoms of there was an efficient emergency call system. The mor- approximately 4 years. Twelve patients presented evi- tality was the same in both groups and no more patients dence of a systemic disease of collagen type and were survived cardiac arrest to leave hospital in the inter- distinguished by the frequency of digital arterial disease, mediate care group than among controls, though initial arthritis, and the presence of serological abnormalities. resuscitation was more often successful. The failure of No such evidence could be adduced in the remainder intermediate coronary care was attributed to the rarity but the clinical similarities suggest aetiological linkage. of primary ventricular fibrillation after discharge from The pregnancy relation is discussed and it is suggested the CCU. that the small pulmonary vessels respond abnormally to stress. One familial case is reported in which the genetically Myocardial infarction in east London determined defect may have been rheumatoid disease. Hugh Tunstall Pedoe (introduced by Wallace Brigden) We suggest that a substantial proportion of cases of St. Mary's Hospital Medical School, London W2 unexplained pulmonary hypertension may be examples of immune complex disease. The London Borough of Tower Hamlets was the Br Heart J: first published as 10.1136/hrt.37.5.548 on 1 May 1975. Downloaded from Proceedings of the British Cardiac Society :5I

British centre in a European epidemiological study of Experience with left main stem coronary coronary heart attacks, supported by the Department of stenosis Health and the World Health Organization. During 33 months 707 attacks in men under 65 were classified as R. Balcon, S. 0. Banim, and R. M. Donaldson (last Definite or Possible Acute Myocardial Infarction, with two introduced) 27I deaths occurring within four weeks of onset (38%); The London Chest Hospital, London E2 9JX and 17I in women with 79 deaths (46%). The places of onset of the attacks and of death were Left main coronary lesions are reported to have a poor recorded, as were details of the timing of these events prognosis, and a high investigative and operative and medical care. Despite the compactness of the area mortality. Eighteen (3 %) of 6oo patients studied had left and a 97 per cent hospital admission rate for survivors, main stem stenoses of 75 per cent or more. All had most fatalities occurred at the place of onset, and only 32 (average grade 2.7/4), which in ii started or per cent in hospital. The survival curve showed a very increased in the previous 6 months. Eleven (6ii%) had high early fatality with an exponential fall with time. electrocardiographic or clinical evidence of previous This fall was constant from I5 minutes to 4 weeks and, infarction. The average maximum exercise load achieved therefore, did not appear to change as the victims came on the bicycle ergometer was 490 kpm min 1 (4802 under medical care. In order to reduce the proportion of Nm min- 1). Eleven were paced to angina at rates from medically unattended deaths emergency services would I10 tO I70/min. Mean resting left ventricular end- need to be speeded up geometrically. Halving the diastolic pressure was i6±9 mmHg (2.I±I.2 kPa). present time taken from onset to coming under care 75 per cent lesions were present in at least one other cor- would anticipate only an additional 5 per cent of all onary artery in I7 patients. Segmental left ventricular deaths. The difficulties of interpreting these interesting dyskinesia was present in I0 and diffuse in i. One re- data are discussed. fused , i died awaiting operation, and i had diffuse ventricular dysfunction. Fifteen underwent sur- gery. One died during induction of anaesthesia. The follow-up on the I4 operated averaged I0.9 months (i tO 36 months). Twelve (86%) are asymptomatic. Two (14%) have grade i angina. It is concluded that patients with left main stem stenosis present a similar clinical Positive correlation of coronary angiographic picture to those with severe coronary disease. - index with maximal exercise level in angina ization with the Sones technique was safe and there was pectoris only one operative death. Results of surgery are similar to other patients, the majority are relieved of symptoms, http://heart.bmj.com/ R. Balcon and D. C. Russell (introduced) and all are improved. The London Chest Hospital, London E2 9JX There has been no reliable method to date of predicting the severity of before angio- Value of left atrial in graphy. An angiographic index has therefore been de- assessment of left ventricular function after signed to estimate the proportion of ischaemic myo- acute myocardial infarction cardium at induction of angina pectoris. This has been shown to give a better correlation with exercise per- G. J. Williams, G. Davies (both introduced), and on September 27, 2021 by guest. Protected copyright. formance than the standard methods of angiographic J. R. Muir scoring. The number of major coronary vessels distal Welsh National School of Medicine, Cardiff CF4 4XN to an 80 per cent or more stenosis is expressed as a per- centage of the total number of such vessels. Seventy- The pulmonary arterial diastolic pressure, a timed five patients with angina pectoris and angiographically vectorcardiogram, and a standard electrocardiogram demonstrated coronary artery disease were studied. A were recorded simultaneously in 32 previously well low (r = 0.27) but significant (P

552 Proceedings of the British Cardiac Society at the initial investigation enabled the patients to be types according to the site of rupture in relation to the separated into three groups corresponding to the pul- ventricular septum (anteroapical, posteroapical, central, monary diastolic pressure: (a) Normal (

(6i grafts); between 6 months and i year the patency There is controversy regarding the mode of formation of http://heart.bmj.com/ rate was 86 per cent (46 grafts) and between i and 4 the normal right . Some contend that it is years it was go per cent (79 grafts). All patients had i formed entirely from the primitive bulbus; others that or more functioning grafts. Patency of grafts to right its infundibulum is of bulbar origin, while its sinus is coronary was 92 per cent (69 grafts), to anterior de- developed from the primitive ventricle. Since it can be scending go per cent (87 grafts) and to circumflex 95 argued that the chambers in specimens of tricuspid per cent (30 grafts). The patency rate was not affected atresia represent the bulbar and ventricular chambers, by age of patient, presence of hypertension or diabetes, respectively, it seemed that study of such specimens may previous infarcts, or additional endarterectomy. There elucidate the problem of right ventricular development. was no evidence of progressive narrowing of the grafts We have studied 26 examples of tricuspid atresia or on September 27, 2021 by guest. Protected copyright. with time. Progression in native vessels was observed in hypoplasia. Our findings indicate that the so-called right IS per cent of the patients, mainly in non-grafted and in ventricle is indeed the primitive bulbus, and that the so- proximal segment of grafted vessels. called left ventricle is composed of the sinus portions of It is concluded that coronary vein grafts continue to both right and left ventricles, and represents the primi- function satisfactorily up to 4 years and that accelerated tive ventricle. The anomaly results from failure of right- progress in native vessels after grafting is uncommon. ward expansion of the primitive atrioventricular canal. The observation that the endocardial cushions were fused eccentrically to form a 'central' fibrous body on the right margin of the canal and a single mitral orifice sup- Post-infarction ventricular septal rupture: ports this hypothesis. Subsequent fusion of the atrial Clinicopathological study septum with their eccentrically positioned cushions, therefore, produces the blind right . It will be Magdi Yacoub, Eid Fawzy, and 3tohn Brennan (last demonstrated that evidence of the right ventricular sinus two introduced) is observed in the 'left ventricles' of most specimens, and Harefield Hospital, Harefield, Middlesex UBg 6JH that the 'dimple', frequently seen in the right atrial floor, communicates with this particular part of the 'left Between I969 and 1974, I9 patients with acute ven- ventricle' rather than with the 'right ventricle'. In one tricular septal rupture were seen at Harefield Hospital, specimen a partly formed valve ring was observed in this 17 were treated surgically. Their ages varied from 44 to position. The tissue considered to represent the ven- 76 years. Rupture occurred 4 to 8 days after infarction. tricular septum is, in fact, the bulboventricular septum, The lesions could be classified into 4 clinicopathological and evidence of the posterior interventricular septum is Br Heart J: first published as 10.1136/hrt.37.5.548 on 1 May 1975. Downloaded from

Proceedings of the British Cardiac Society 553 usually present in the 'left ventricle'. The significance In a series of 325 Mustard operations, 73 were per- ofthese findings to 'single ventricle with outlet chamber' formed in infants. Sixty patients had simple transposition was presented. of great arteries; there were 5 early and 3 late deaths. Twelve patients had transposition ofthe great arteries and ventricular septal defect; there were 6 early and 3 late Surgical repair of conotruncal abnormalities deaths. One patient had transposition of the great Christopher Lincoln, Elliot Shinebourne, Michael arteries and pulmonary stenosis, and he survived. A Joseph, Ronald Gibson, and Robert Anderson high incidence of systemic venous obstruction, mainly (introduced) in the group of infants where a 'dacron' patch was used, The Brompton Hospital, London SW3 6HP led us to go back to using and to change the size and shape of the intra-atrial baffle. The results of It has recently been shown that transposition and mal- this new technique are encouraging. position are morphogenetically closely linked. It follows, Our present policy can be summarized as follows: therefore, that an understanding of the developmental Balloon septostomy is performed at initial catheteriza- processes and positional variations of the underlying tion in all infants. Simple transpositions of the great right ventricular anatomy can make for easier under- arteries are reinvestigated at 4 to 5 months of age. standing of these complex anomalies, and help in their Mustard operation is then performed between 6 and corrective surgery. 12 months of age, or earlier if deterioration occurs. Be- The development and position of the septal insertion cause of the high incidence of and pul- ofthe conus septum influences the intraventricular repair monary vascular disease, patients with transposition of conotruncal abnormalities. of the great arteries and ventricular septal defect are Nine patients, 4-20 kg, have been studied and cor- operated in infancy. In patients with transposition of rected. great arteries, ventricular septal defect, and pulmonary i) Four had 'complete' 1-transposition of the great stenosis, a systemic to shunt is per- arteries with a subaortic ventricular septal defect. formed in infancy if necessary. 2) One had double outlet right ventricle with a sub- aortic ventricular septal defect. Long-term cardiorespiratory assessment after 3) Two had double outlet right ventricle with a sub- surgical closure of ventricular septal defect in pulmonary ventricular septal defect. childhood 4) Two had double outlet right ventricle with 1- malposition of the and a subaortic ventricular Katherine A. Hallidie-Smith, R. E. Edwards, defect. septal R. Wilson, and E., Zeidifard (last three introduced) http://heart.bmj.com/ In(i)the conus septum is hypoplastic or absent. There- Royal Postgraduate Medical School, London W12 oHS fore, the ventricular septal defect is immediately sub- aortic. In (2) the septal insertion of the conus septum This study was designed to find out whether surgical cor- blocks off the left anterior half of the ventricular septal rection of a large ventricular septal defect in childhood defect. In (3) and (4) the septal insertion of the conus can result in normal cardiorespiratory function in adult septum is to the posterior part of the interventricular life. septum, the primary bulboventricular foramen persists Twenty-six patients aged 3 to 12 years at operation as the ventricular septal defect and is beneath the left- now 9 to i6 years after operation, had evidence of pul-

sided conus, which in (i) and (4) gives rise to the aorta, monary vascular disease preoperatively, with one on September 27, 2021 by guest. Protected copyright. but in (3) the pulmonary artery. exception. In corrective surgery the intraventricular repair must All are now leading normal lives and only one admits either re-route blood from the left ventricle into the to fatigue on effort. Respiratory function tests and aorta (2, 4) or the pulmonary artery (3). After this, in exercise studies on I8 patients showed normal values (i) and (3) venous inflow must be re-routed at atrial for FEV1.0, vital capacity, and transfer factor for CO. level by an interatrial baffle. Eight children are well, and Exercise tolerance was assessed with an increasing work one died 3 months after operation. load test and was essentially normal for the group. Heart rate, ventilation, and pulmonary gas exchange increased normally with exercise. In a constant work-rate Current surgical management of transposition exercise test, cardiac output, dead space, tidal volume of great arteries in infancy ratio, and blood lactate concentration were within the normal range. J. Stark, M. de Leval, D. J. Waterston (last two in ii patients showed pro- introduced), and R. E. Bonham Carter gressive pulmonary hypertension in comparison with The Hospital for Sick Children, London WCI earlier study 8 years previously (i to 8 years post- operatively) (Hallidie-Smith et al., I969) and there was a The natural history of transposition of the great arteries striking increase in pulmonary artery pressure during has been considerably modified by palliative procedures. supine and erect bicycle exercise. However, despite an initial improvement, continuing The severity of the pulmonary hypertension is in morbidity and mortality still make an early repair de- contrast with the functional status and may imply an sirable. unusually benign course. Nevertheless, these results Br Heart J: first published as 10.1136/hrt.37.5.548 on 1 May 1975. Downloaded from

554 Proceedings of the British Cardiac Society

strengthen the case for early closure of ventricular septal group all of whom were male. Dyspnoea was the com- defect. monest presenting symptom with a systolic ejection murmur and hepatomegaly as the commonest signs. Reference All patients in this group underwent open aortic valvo- Hallidie-Smith, K. A., Hollman, A., Cleland, W. P., Bentall, tomy and/or valvuloplasty, with 3 deaths. A late follow- H. H., and Goodwin, J. F. (I969). British Heart Journal, up of the survivors will be presented. 32, 246. In summary, a series of 27 patients up to the age of i year with critical obstruction of either the pulmonary or aortic valves will be presented. This is one of the larger Late results of homograft reconstruction of right series to be reported in this age group. ventricular outflow tract in infants and children Rosemary Radley-Smith and Magdi Yacoub Harefield Hospital, Harefield, Middlesex UB9 6JH YOUNG RESEARCH WORKERS PRIZE Between March I970 and July I974, 2I children under- Role of pulmonary veins in regulation of lung went successful reconstruction of their right ventricular capillary blood flow outflow tract with adult-sized fresh aortic homografts. Their ages were between 4 months and I3 years. Twelve B. Rajagopalan (introduced by G. de J. Lee) patients were below 4 years of age. The lesions cor- The Radcliffe Infirmary, Oxford OX2 6HE rected were truncus arteriosus, pulmonary atresia with Lung capillary blood flow is pulsatile. The patterns of ventricular septal defect, pulmonary atresia with intact capillary blood flow in normal man and in patients with septum, absent pulmonary valve, double outlet right diseases affecting the right and left heart have previously ventricle, transposition of the great arteries with ven- been documented from tricular septal defect and pulmonary stenosis, and severe Oxford and elsewhere. These Fallot's tetralogy. studies suggested that both pulmonary arterial and Ten patients have been reinvestigated 2 weeks to 50 venous mechanisms played a part in maintaining lung months after In no is the capillary blood flow pulsatility in arterialized form. operation. patient gradient Previous from this across the pulmonary valve more than I2 mmHg work laboratory, both in animal (I.6 kPa) and the homograft is functioning well. The model studies and in man, demonstrated that lung cap- is now at level in illary blood flow remained normally pulsatile over a wide pulmonary artery pressure systemic range of 2 patients who underwent operation at 7 and I2 years of pulmonary artery pressures. This was shown to be because of a hyperbolic relation between http://heart.bmj.com/ age, respectively. In the remaining patients the pul- pulmonary monary artery pressure is between 20 and 40 mmHg artery resistance and compliance. (2.7 to 5.3 kPa). There is no evidence of reopening Some of the human capillary flow studies had also the ventricular septal defects. shown that left atrial pressure transients, such as cannon It is concluded that homograft reconstruction of the waves in patients with complete AV dissociation, did not right ventricular outflow tract in infants and children impede capillary blood flow until the mean left atrial gives satisfactory results. pressure was grossly raised. This finding led me to the investigation ofpulmonary venous pressure-flow relations and their role in regulating capillary blood flow. Critical outflow valve obstruction under the age The pulmonary veins are collapsible structures and so on September 27, 2021 by guest. Protected copyright. of i year special methods were developed for measuring blood flow in them, using electromagnetic flow meters. It was S. C. Lennox, J. C. R. Lincoln, M. Paneth, E. A. found that the pattern of pulmonary venous blood flow Shinebourne, and M. C. Joseph was a mirror image ofthe left atrial pressure fluctuations, The Brompton Hospital, London SW3 6HP and that there was considerable variation in venous flow waveform. This report represents the Brompton Hospital experience Pulmonary venous and capillary flows were measured of infants and neonates with critical pulmonary valve simultaneously in order to investigate whether the stenosis and aortic valve stenosis. There were I9 patients changes in venous waveform were reflected in capillary with critical pulmonary valve stenosis and 8 with critical flow. This was found not to be the case. aortic valve stenosis. A hypothesis based on the collapsible nature of the Critical pulmonary stenosis: Among the I9 patients up pulmonary veins was formulated to explain the de- to i year of age, 8 were girls, and the commonest pre- coupling of the capillary bed and left atrium described senting symptom was cyanosis seen in I5, the commonest above. The consequences of this hypothesis were then physical sign being a systolic ejection murmur with a tested by appropriate experiments. The results con- single 2nd sound. A more detailed analysis of the firmed the existence of both the decoupling phenomenon symptoms, signs, and findings at special investigation and the collapsible behaviour of the main pulmonary will be presented. The evolution of a satisfactory tech- veins. nique of operation will be indicated in these critically Pulmonary venous velocities were then studied in man ill patients, and the late follow-up will be presented. and the results confirmed that the results of animal Critical aortic stenosis: There were 8 patients in this studies were broadly applicable to man. Br Heart J: first published as 10.1136/hrt.37.5.548 on 1 May 1975. Downloaded from

Proceedings of the British Cardiac Society 555

The role of this reservoir function of the pulmonary a different biochemical basis and thus has different vein in protecting the lung capillaries from left heart metabolic and functional consequences. In studies with a pressure transients in the normal state and in left heart rat heart model we have shown that methods which disease is discussed. induce cardiac arrest without depleting cellular energy reserves (e.g. coronary perfusion with hypothermic solutions or solutions containing high concentrations of Biological and pharmacological myocardial potassium) permit extended periods of arrest followed by elimination rate of good functional recovery. In contrast, methods causing a Yohn Coltart depletion of energy reserves (e.g. ischaemic arrest or St. Thomas's Hospital, London SEI 7EH electrically induced ventricular fibrillation) render the heart susceptible to damage and lead to a poor functional Recent reports have suggested that propranolol should be recovery. The results stress the importance of ensuring withdrawn several weeks before open heart surgery. How- continuous coronary perfusion during arrest in order to ever, early withdrawal has resulted in rebound crescendo maintain adequate cellular energy production for myo- angina and infarction. The purpose of this study was to cardial preservation. define a safe period for withdrawal of propranolol therapy. 14C propranolol was administered orally, 41-43 mg (25-75 ,uCi) or intravenously, I mg (25 tCi) to patients undergoing mitral . Plasma, , adipose tissue, and myocardial tissue Myocardial biopsy: description of technique, were assayed. After intravenous propranolol plasma ti comparison of right and left ventricular biopsy varied between I.5 to 5.o hours with little change in total plasma radioactivity within ten hours. No propranolol lain Brooksby, Stephen Jenkins (both introduced), was detected in the myocardial tissue 8.25 tO I0.5 hours John Coltart, Michael Webb-Peploe, and Michael from dose, though the total tissue radioactivity indicated Davies the presence of small amounts of metabolites. These are St. Thomas's Hospital, London SEI 7EH biologically inactive, since 's and inotropic challenge had returned to control levels by Using a long sheath technique via the venous transseptal, 6.5 hours. After oral propranolol, most of the plasma arterial left ventricular, and venous right ventricular radioactivity was caused by metabolites of the , route, over 250 myocardial biopsies have been performed indicating first passage hepatic extraction of propranolol. from the right/or left ventricle in over ico patients. In one patient, low levels of radioactivity were detected Biopsies were performed in patients with aortic valve in the myocardium at 28 hours; tissue 14C propranolol disease, cardiomyopathy, or rheumatic heart disease but http://heart.bmj.com/ level in this patient was below the threshold of pharma- were not undertaken if there was any evidence of cological activity. No myocardial radioactivity was de- ischaemic heart disease. tected in other patients undergoing surgery 24 to 97 Complications, all associated with right ventricular hours after the oral dose. No radioactivity was detected biopsy, occurred in 1.2 per cent of biopsies, haemo- in skeletal muscle tissue, but adipose tissue showed some pericardium of no haemodynamic significance in 2 depot unchanged propranolol. patients, and ventricular requiring electro- In vitro myocardial dose-response curves to isoprena- version in another patient. The biopsies were examined line showed no difference in tissue obtained from by both light and electron microscopy, and by histo-

patients who had previously received propranolol and chemical staining. on September 27, 2021 by guest. Protected copyright. those who had not. In 20 patients, both left and right ventricular biopsies In a consecutive series of patients, the operative were obtained; the right ventricular morphology mortality of patients who had never received propranolol differed conspicuously from left ventricular morphology was 5 per cent and 3 per cent in those in whom pro- in 59 per cent of cases. The right ventricular biopsy pranolol was discontinued between i and ii days before consisted of fibrous tissue or adipose tissue in 24 per surgery. This study defines 24 hours as an adequate safe cent, and in 2 cases it included pericardium. The histo- withdrawal period for complete myocardial elimination logical appearance was similar in biopsies from both of propranolol and pharmacologically active metabolites right and left ventricles in I7 per cent. in patients undergoing operation or other interventions. Analysis of myocardial cell size suggests that biop- sies taken from the right ventricular surface of the inter- Myocardial preservation during elective cardiac ventricular septum consist of a mixed population of arrest right and left ventricular muscle cells, and may thus afford some indication of disease processes affecting the D. J. Hearse (introduced by J. P. Shillingford) left ventricle. However, accurate placement of the biop- Imperial College, Department of Biochemistry, tome on the septum cannot be ensured. Our experience London SW7 would suggest that left ventricular biopsy is: a) safer than right ventricular biopsy; and b) more likely to Elective cardiac arrest may be induced by a variety of obtain a biopsy sample that is representative of patho- procedures used either singly or in combination and logical changes affecting the myocardium which are with or without coronary perfusion. Each procedure has more often pronounced in left than right ventricle. Br Heart J: first published as 10.1136/hrt.37.5.548 on 1 May 1975. Downloaded from

556 Proceedings of the British Cardiac Society

Percutaneous technique of left ventricular ability of the microsomal fractions to accumulate Ca2 + biopsy, and comparison between right and left by the binding process. Under in vivo conditions it ventricular myocardial samples reduced the activity of the Ca2+-activated myofibrillar ATPase enzyme. P. J7. Richardson (introduced), E. G. J. Olsen, D. E. Jewitt and S. Oram Primary restrictive cardiomyopathy King's College Hospital, London SE5 9RS G. M. Ziady (introduced), Celia M. Oakley, M. J. has been performed from the Raphael, and J. F. Goodwin left ventricular cavity previously, but it could only be Royal Postgraduate Medical School, London WI2 oHS achieved by means of an arteriotomy of the carotid or brachial arteries. The improved design of the King's During investigation of patients with cardiomyopathy a endomyocardial bioptome has facilitated the develop- new group has been recognized. These patients show a ment of percutaneous transfemoral left ventricular biopsy unique fault in left ventricular diastolic function. This with a sheath technique. Repeated left ventricular fault is manifested by restriction of left ventricular sampling has been made possible without recatheteriza- volume, without reduction of the rate of ventricular tion of the aortic valve and the technique has been un- filling, and has been attributed to endocardial disease. complicated. Seven patients aged 32 to 6o years were seen over a 2- The clinical value of ventricular biopsy, particularly of year period, and were studied by and the left ventricle, is discussed. Sixty-five patients have angiocardiography. All except one were Europeans. Of been biopsied, and in i5 patients biventricular biopsy the 7, 6 had chest pain. In 4, the fault was confined to has been performed. All samples have been evaluated by the left ventricle. There was involvement of the right histological, histochemical, and ultrastructural methods, ventricle also in 3, and these 3 patients showed some and have shown no major differences between right and clinical resemblance to constrictive pericarditis. left ventricular samples, though minor differences do The left ventricular diastolic pressure showed a steep exist between the ventricles. Diffuse disease processes early diastolic rise to a plateau without a prominent a such as congestive cardiomyopathy have been found to wave in 4 out of the 7 (the early diastolic pressure show identical features in the right and left ventricles. ranged between 2 and 7 mmHg (0.3 and o.9 kPa) and the In patients with primary left ventricular pathology such end-diastolic between i8 and 40 mmHg (2.4 and 5.3 as hypertrophic cardiomyopathy or left-sided valvar kPa)). Cineangiography showed a small thick-walled left lesions, biopsy of the left ventricle is preferable. ventricle with a smooth rather featureless outline (end- diastolic volume 46 to 86 ml m-2). Systolic contraction

Oxyfedrine-induced changes in the structure was normal (ejection fraction 73 to 87%) and the end- http://heart.bmj.com/ and function of cardiac muscle systolic volume ranged between IO and I7 ml m-2. The distinctive nature of the haemodynamic fault was further Winifred G. Naylor, W. Burian (introduced), and revealed by study of the instantaneous pressure-volume M. Petch relation in 3 out of the 7 patients. At the beginning of Cardiothoracic Institute, London WiN 2DX diastole both the pressure and volume were within nor- mal relation, but towards the end of diastole, the pressure (L-3-methoxy-(I-hydroxy-I-phenylisopro- climbed steeply to higher levels while the left ventricular pylamino)-propriophenone hydrochloride) is an effective volume failed to increase correspondingly. The coronary drug. When given acutely it acts as a partial arteries were normal. Cardiac biopsy was carried out in 2 on September 27, 2021 by guest. Protected copyright. agonist at beta-adrenoceptor sites, but prolonged ad- patients. One patient died and necropsy was performed. ministration results in the establishment of beta-adreno- The pathological findings were those of moderate left ceptor blockade. ventricular hypertrophy and fibrosis with thick endo- When injected intraperitoneally into rabbits oxyfedrine cardium, but there was no eosinophilic infiltration. causes dose-dependent changes in the fine morphology The terms restrictive and constrictive cardiomyo- of cardiac muscle cells. These changes are characterized pathy have been used before but the left ventricular fault by a proliferation of the cell membrane, lysis of the has not been examined in detail. A restrictive form of myofibrils, and vacuolization of the mitochondria. The cardiomyopathy has now been defined in which the Z band substance remains intact and attached to the cell haemodynamic fault differs fundamentally from that in membrane, despite evidence of tissue swelling. These the hypertrophic or dilated cardiomyopathies, from changes are not caused by a release of endogenous cate- amyloid heart disease or endocardial fibroelastosis. The cholamines, because the noradrenaline content of rabbit dysfunction is believed to be secondary to endocardial heart muscle remained unchanged despite the occurrence disease in most, if not all cases. of these other indices of cell damage. Other oxyfedrine- induced changes in the fine morphology of heart muscle Continuous assessment of left ventricular shape cells included thickening of the basement coat substance, in man and evidence of to collagen deposition. Heart weight D. G. Gibson and D. Brown body weight ratio remained relatively constant, but high J. (introduced) The London 6HP concentrations of oxyfedrine caused the rabbits to lose Brompton Hospital, SW3 weight. Frame-by-frame analysis of left ventricular angiograms Relatively high doses of oxyfedrine interfered with the has been performed in IO normal subjects and go Br Heart J: first published as 10.1136/hrt.37.5.548 on 1 May 1975. Downloaded from

Proceedings of the British Cardiac Society 557

patients with heart disease. As well as calculating stan- Observations on relation between heart sounds dard parameters, left ventricular shape index was de- and valve movements by simultaneous echo- rived as (cavity area)/(perimeter)2, which has a maximum and phonocardiography value when the outline is circular. In normal subjects, systole was always associated with progressive reduction Aubrey Leatham and Graham Leech (introduced) in shape index. This change was less pronounced in St. George's Hospital, London SWIX 7EZ patients with low ejection fraction, and also when anterior or inferior ischaemia was present, even though By recording echoes from all four valves with high- ejection fraction was normal. During early diastole, frequency phonocardiograms, temporal relations be- shape index rose rapidly due to an increase in minor tween valve motions and heart sound components can diameter occurring throughout the period of rapid filling. be identified. This preceded any changes in long axis, which were This technique has been used clinically for several associated with upward movement of the aortic root as months. Preliminary results indicate that: well as outward movement of the apex. The pattem of i) Each valve closure is precisely coincident with the wall movement during atrial systole differed from that in onset of a high frequency sound. early diastole in being mainly caused by an increase in 2) In normal subjects with a single first sound, mitral long axis. These results have clear functional implica- and tricuspid valves close almost simultaneously. tions, and suggest that wall movement during filling, in 3) In normal subjects with two major first sound particular, may be strikingly non-uniform, and that components, the first coincides with mitral closure and tacit assumptions about cavity shape used in the deriva- the second with tricuspid closure. tion of wall properties from estimates of ventricular 4) Where mitral and tricuspid closures are grossly volume may require modification. asynchronous, as in right bundle-branch block or paced patients, each valve closure has an associated sound. 5) Ejection sounds occur at the moment of maximal semilunar valve opening. Pulmonary ejection sounds occur at this point, whether associated with pulmonary stenosis or hypertension. 6) Midsystolic clicks associated with the mitral valve Early diastolic events in cardiac disorders prolapse occur when displacement of the valve leaflets towards the atrium is halted. Taylor Prewitt (introduced), Derek Gibson, It thus seems reasonable to postulate that high fre- David Brown (introduced), and George Sutton quency cardiac sounds are associated with the halting of The Brompton Hospital, London SW3 6HP valve leaflets after movement initiated by pressure http://heart.bmj.com/ changes. Left ventricular events during early diastole have been studied using non-invasive techniques in 52 patients. Echocardiographic estimation of the systolic Simultaneous echocardiograms, showing mitral valve pressure gradient in aortic stenosis cusps and transverse dimension, apex cardiograms, and phonocardiograms were recorded and digitized. These D. H. Bennett (introduced), D. W. Evans, and were correlated with micromanometer pressure traces M. V. J. Raj (introduced) and frame-by-frame analysis of cineangiograms. Events Regional Cardiac Unit, Papworth Hospital, were studied during: Cambridge CB3 8RE on September 27, 2021 by guest. Protected copyright. i) Isovolumic relaxation, from aortic valve closure Values for systolic wall stress have been shown to be (A2) to mitral valve opening. similar for normal and hypertrophied left ventricles in 2) Early filling, from mitral valve opening to the o point the absence of heart failure. on the apex cardiogram. A constant representing systolic wall stress was derived 3) Period of 'rapid filling' on the apex cardiogram, from echocardiographic measurements of left ventricular from the o point to the third heart sound. systolic wall thickness and cavity minor axis, together with systolic blood pressure measured by sphygmomano- Increased transverse diameter before mitral valve meter, in I2 normal subjects. This constant (mean value opening was demonstrated in all patients, except those II0, SD ±7) was validated in I2 patients with left ven- with severe mitral regurgitation or left ventricular tricular hypertrophy not due to aortic stenosis. disease. Significant left ventricular filling (dimensional Using the simple relation: Left ventricular systolic changes after mitral valve opening) occurred in all m patients while left ventricular pressure was still falling. pressure = I0 x systolic wall thickness 2 axis, and 'Rapid filling' on the apex cardiogram and the third sphygmomanometric measurements of systemic pres- heart sound bore no consistent relation to wall move- sure, systolic aortic pressure gradients were calculated in ment, suggesting that factors other than filling contri- 20 patients with varying degrees of aortic stenosis. These bute to their genesis. On the basis of these results, a estimates compared favourably (r = o.84, P

558 Proceedings of the British Cardiac Society

Echocardiographic assessment of severity of left ventricula,r end-diastolic volume, ejection fraction, aortic regurgitation end-diastolic wall stress, wall stiffness, ventricular mass, and ratio of mass to left ventricular end-diastolic K. E. Gray (introduced), D. W. Barritt, and volume. F. G. M. Ross Thus the change in contractility seems to be a pri- Bristol General Hospital, Bristol BSi 6SY mary phenomenon in the human heart, and is not necessarily linked to a change in left ventricular end- Echocardiographic measurement of left ventricular diastolic pressure, left ventricular end-diastolic volume, dimensions may offer a non-invasive technique for docu- or left ventricular end-systolic volume. We do not think menting the severity of aortic regurgitation and pro- alternans is caused by changes in end-diastolic fibre viding criteria on which to base the long-term assess- length, decreased diastolic filling period, or decreased ment of left ventricular function in this lesion. diastolic compliance before the small beat. Left ventricular diameter was measured by an ultra- Pulsus altemans is primarily caused by an alteration sound technique using a Smith Kline Ekoline 20 ultra- of contractility. sonoscope in 20 patients with aortic regurgitation, and in 20 normal subjects. Estimates were made of the stroke volume, left ventricular output, and ejection fraction by Preoperative assessment of patients with the method of cubing the left ventricular diameter Wolff-Parkinson-White syndrome measured at end-diastole and end-systole. In patients with aortic regurgitation of more than H. C. Miller, R. H. Svenson, J. J. Gallagher, and mild severity, the left ventricular end-diastolic dia- A. G. Wallace (all introduced by G. A. H. Miller) meter, stroke volume, and left ventricular output were The Brompton Hospital, London SW3 6HP increased compared with normals. The mean left ven- Successful surgical of tricular end-diastolic diameter was cm correction the WPW syndrome 8.I (range 5.4- depends upon accurate preoperative localization of the 9.i) in the patients, compared with 4.9 cm (range 4.2- accessory pathway and confirmation that the accessory 5.8) in the normals, and the mean stroke volume 230 ml (range I25-465) compared with 83 ml (range 46-158). pathway participates in circus tachycardia. The acces- The mean left ventricular was sory pathway was localized at surgery by epicardial output I6.7 1 min- in (range I0-3I) in the patients, compared with 5.3 1 min mapping 13 consecutive patients (6 in the lateral (range 3.o-8.5) in the normals. The ejection fraction mitral ring, 2 in the lateral tricuspid ring, and 5 in the was similar in both groups. septum). With lateral accessory pathway, preoperative pacing of the atrium The severity of aortic regurgitation was also graded by adjacent to the accessory pathway clinical and radiological methods. The echocardio- caused more pre-excitation than pacing the contralateral http://heart.bmj.com/ atrium distant from the accessory graphic data were compared with this grading to assess pathway. Pacing from the value of the method. both sides in 3 of 5 patients with septal accessory path- way caused equal pre-excitation in i, and more pro- nounced pre-excitation from the right atrium or left Pulsus atrium in 2. During circus tachycardia the QRS com- alternans: force-velocity and angiographic plex showed volume analysis in man no delta wave and simultaneous recordings from the low lateral right atrium, low atrial septum, and R. H. Swanton, B. S. Jenkins, I. A. B. Brooksby (all left atrium (via coronary sinus) revealed that retrograde

introduced), and M. M. Webb-Peploe atrial activation occurred early in all cases and in an on September 27, 2021 by guest. Protected copyright. St. Thomas's Hospital, London SEI 7EH abnormal sequence in those with lateral accessory path- way. The earliest atrial activity always occurred adjacent Pulsus alternans was studied haemodynamically in 8 to the accessory pathway during circus tachycardia and patients: 6 had aortic valve disease, I mild aortic and during ventricular pacing with retrograde conduction mitral valve disease with severe coronary artery disease, over the accessory pathway. The accessory pathway was and i a cardiomyopathy. successfully divided in 9 of these I3 patients and Cardiac output was measured by indocyanine green arrhythmias were abolished. dye dilution. Pressures for force-velocity analysis were taken using Telco (MM52) or Millar catheter tip mano- Surgical treatment of ventricular tachycardia meters, and KVma, derived. Angiographic volume following epicardial mapping studies analysis was performed using a light-pen computer system, with films taken in the right anterior oblique R. A. J. Spurrell (introduced), A. E. Yates, E. Sowton, projection. and D. C. Deuchar The only features shared by all 8 cases were: a low Guy's Hospital, London SEi 9RT cardiac index; alternating LV systolic pressures; alter- nating diastolic filling period; alternating max and min Four patients with intractable ventricular tachycardia dP/dt, and alternating KVmax. were studied using programmed electrical stimulation Inconsistent factors in this study of pulsus alternans of the heart, and shown to have a re-entry mechanism were: Alternating left ventricular end-diastolic pressure, as the basis for the tachycardia. All 4 patients underwent alternating left ventricular end-diastolic volume, alter- epicardial mapping studies at open heart surgery. In nating left ventricular end-systolic volume, absolute each patient the tachycardia was initiated and the epi- Br Heart J: first published as 10.1136/hrt.37.5.548 on 1 May 1975. Downloaded from

Proceedings of the British Cardiac Society 559 cardial activation times from 40 to 50 points on each in association with sinus arrest, junctional rhythm, and ventricle were obtained using a bipolar electrode. After bouts of atrial flutter/fibrillation. However, in many in- this the epicardial activation sequence during tachy- stances, though a history of syncopal attacks and palpita- cardia was plotted in the form of an isochrone map. In tions is obtained in association with bradycardia, it is Case i the re-entry activation front was found to begin often hard to prove that sinoatrial dysfunction is re- in the posterobasal region of the left ventricle; in Case 2 sponsible since serial electrocardiograms may fail to the re-entry front was found in the anterobasal region of capture the offending rhythms. Special investigations the right ventricle; in Case 3 the re-entry front was are needed in order to distinguish between physio- found to be in the outflow tract of the right ventricle logical and pathological bradycardia. The paper reports involving the adjacent interventricular septum, and in the results of atrial overdrive suppression, premature Case 4 the re-entry front was found on the anterior sur- atrial stimulation, and His bundle face of the left ventricle adjacent to the interventricular as means of attempting this distinction. Forty-eight septum. In each patient an appropriate transmyocardial cases of suspected sinoatrial disorder were investigated incision was made across the anterograde part of the re- and compared with 63 patients with heart block but with entry front in order to interrupt the re-entry pathways. no evidence of sinoatrial disease. Cases I, 3, and 4 had short-lived attacks of tachy- cardia in the immediate postoperative period, but all 4 are free from tachycardia. patients Extending the life of a pacemaker 7. Geoffrey Davies (introduced) and Aubrey Leatham Repetitive and established paroxysmal London St. George's Hospital, SWIX 7EZ all removed electively Dennis Krikler and Paul Curry (introduced) For the past 6 years pacemakers oHS from patients at St. George's Hospital have been placed Royal Postgraduate Medical School, London W12 in an incubator to continue simulated pacing conditions. The units have been checked at regular intervals to de- In repetitive paroxysmal tachycardia (Parkinson Papp termine how they have been functioning and in par- syndrome) episodes are usually separated by no more ticular to establish the modes of failure. than one or two sinus beats, and are initiated by extra- Using these results, it has been possible to extend systoles that activate a re-entry circuit; the location may reliably the period of patient-use to 3 years for a fixed be atrial, AV nodal, or ventricular. We have observed 7 Devices unit. However, the major cause of pre- patients who meet these criteria and confirm the usual rate mature failure is associated with batteries. In order to http://heart.bmj.com/ absence of underlying disease, relative freedom from safeguard against this a unit has been developed which symptoms, and benign prognosis. enables the patient to check the functioning of his pace- A different form of AV nodal reciprocating tachy- more if with- cardia has recently been characterized, usually in chil- maker daily (or often necessary) at home cases in most out the need for frequent visits to the pacing clinic. This dren or young adults, and we describe 9 in turn has led to a total decrease in attendances at of whom programmed electrical stimulation of the a to heart was included in the diagnostic assessment. The clinics without diminishing service pacemaker oldest subject was 27. Attacks tend to be of long duration patients. and also to be separated by relatively brief episodes of sinus rhythm or AV nodal dissociation. During attacks, on September 27, 2021 by guest. Protected copyright. the electrocardiogram usually suggests 'left atrial 24-hour electrocardiogram monitoring of rhythm'. We have also recognized 4 cases in whom this ambulatory outpatients suspected of mechanism has initiated reciprocating tachycardia in the dysrhythmias Wolff-Parkinson-White syndrome. In these tachycardias reciprocation is induced by critical increases in heart A. D. Goldberg, P. Cashman (both introduced) and rate; therapy and prophylaxis require control of sino- E. B. Raftery atrial and nodal discharge as well as modification of AV Northwick Park Hospital, Harrow, Middlesex nodal and/or 'bypass' conduction. HAI 3UJ Continuous 24-hour electrocardiogram monitoring using Overdrive suppression and other tests of the Oxford tape recorder system was performed on I30 sinoatrial function ambulant outpatients who presented to the General Medical Clinic with symptoms of blackouts, dizzy Roger C. Evans, Christopher A. Kekwick (both turns, faints, or palpitations. Twelve-lead electro- introduced), and David B. Shaw cardiogram at rest and on exercise was normal in 56 per Royal Devon and Exeter Hospital, Exeter EX2 5DW cent and abnormal but not diagnostic in 36 per cent. In these patients 24-hour monitoring of the electrocardio- The features of chronic sinoatrial disease are now a well- gram revealed dysrhythmias accounting for the symp- recognized entity and the diagnosis is relatively straight- toms in 6o per cent, and in a further 24 per cent dysrhy- forward. These patients usually have sinus bradycardia thmias were seen but not sufficient to account for the Br Heart J: first published as 10.1136/hrt.37.5.548 on 1 May 1975. Downloaded from

560 Proceedings of the British Cardiac Society symptoms. The remaining i6 per cent were in sinus Effects of on baroreflex arc in rhythm throughout. conscious rabbits and man In those 8 per cent with i2-lead electrocardiograms considered diagnostic, additional unsuspected dysrhyth- P. Sleight, P. I. Korner, J. R. Oliver, J. L. Robinson, mias were revealed in 63 per cent. J. P. Chalmers, and M. J. West (last five introduced) Supraventricular dysrhythmias alone were seen in 46 The Radcliffe Infirmary, Oxford OX2 6HE per cent, ventricular dysrhythmias in 6 per cent, and both supraventricular and ventricular dysrhythmias in The action of clonidine (Catapres) on single aortic nerve 32 per cent. Episodes of ventricular tachycardia were baroreceptor fibre discharge was examined in anaesthe- seen in 5 per cent of patients and atrial arrest (2 to 30 s) tized normotensive and renal hypertensive rabbits. There with no ventricular escape in 8 per cent. is an increase in discharge at a given arterial pressure We conclude that in patients suspected of dysrhyth- which is dose dependent. mias 24-hour monitoring of the electrocardiogram gave We also compared the effects of graded doses of intra- positive diagnosis even in the presence of a normal or venous clonidine (0.25-3.0 ,tg kg- 1 min 1) and clonidine non-diagnostic i2-lead electrocardiogram. injected into the lateral cerebral ventricle 0.5-I.5 ,ug kg-') on the mean arterial pressure-pulse interval re- sponse curves of unanaesthetized normotensive and renal Computer and human interpretation of hypertensive rabbits in order to assess in each the electrocardiogram correlated with cardiac excitability of the cardiac autonomic effectors. In both pathology normal and hypertensive rabbits there was a striking increase in the gain of the baroreflex arc controlling P. J. Bourdillon, D. Kilpatrick, and J. Maldonado heart rate. This was largely because of a sensitization (all introduced by J. F. Goodwin) of vagal motoneurones. Royal Postgraduate Medical School, London WI2 oHS It is concluded that at least part of the hypotensive effect of clonidine is mediated through increased sensi- To assess the performance of the Cardionics 12-lead tization of the baroreflex arc. electrocardiogram computer programme in patients with Preliminary results of the action of clonidine on the heart disease, comparisons have been made with both baroreflex arc in man are presented. the patients' clinicopathological data and the electro- cardiographic interpretations of two human readers. In the study were I2 patients with aortic valve disease, Problems associated with development of 22 with mitral valve disease, i5 with coronary artery radioimunoassay for urinary digoxin and its use http://heart.bmj.com/ disease, IO with cardiomyopathy, and a miscellaneous in clinical assessment of biological availability group with congenital heart disease and pulmonary hypertension. The clinico-pathological data were ob- R. P. Hayward, Helena Greenwood (both introduced), tained from clinical examination, biochemical studies, and J. Hamer lung function tests, radiology, echocardiography, cardiac St. Bartholomew's Hospital, London ECiA 7BE catheterization, , and necropsy material. The electrocardiograms were read initially double- Determination of urinary digoxin excretion seems to blind by the human readers. They then compared and offer advantages since single plasma measurements combined their interpretations to arrive at the inter- cannot account for fluctuating levels, and serial measure- on September 27, 2021 by guest. Protected copyright. pretation used for the study. ments are inconvenient. Urinary excretion depends on From the clinicopathological data it was estimated that plasma levels over a period of time, and reflects dose 45 patients either had left ventricular hypertrophy or administered and biological availability. Studies using conditions causing it. The computer diagnosed 28 cor- single doses of tritiated digoxin suggest a high recovery rectly, with 2 false positives; the human readers diag- of digoxin in the urine, with little catabolism. nosed 22 correctly with 2 false positives. 35 patients This study employs a simple specific radioimmuno- similarly had right ventricular hypertrophy. The com- assay for urinary digoxin, developed from one previously puter diagnosed 6 with i false positive; the human described for plasma, applied to the measurement of readers diagnosed II with 2 false positives. 14 patients digoxin excreted by patients in a steady state, on had anterior myocardial infarction. The computer diag- maintenance therapy with several oral digoxin prepara- nosed 5 with 12 false positives; the human readers 4 tions. with 8 false positives. I2 patients had lateral infarcts. Twenty-four urinary levels were found to be pro- The computer diagnosed 2 with 4 false positives; the portional to dosage in each patient, and varied between human readers 3 with o false positives. I3 patients had individuals, though consecutive 24-hour collections infero-posterior infarcts. The computer diagnosed 4 from an individual were similar. Total urinary recovery with 2 false positives; the human readers 4 with i false was low. This is possibly because of analytical errors positive. (unlikely because of the high precision and accuracy of It is concluded that present techniques of I2-lead the assay and reproducibility using another assay), high electrocardiographic diagnosis of patients with heart biliary excretion, or, more likely, the excretion of signifi- disease, either by computer or by human reader, give a cant concentrations of a digoxin metabolite not detected correct diagnosis in only 38 per cent of cases. by the assay.