sign in sign up
<<
Home , Coronary artery disease

British Journal, I97I, 33, Supplement, I87-I93. Br Heart J: first published as 10.1136/hrt.33.Suppl.187 on 1 January 1971. Downloaded from Prognosis of idiopathic in Jamaica with reference to the coronary and other factors

K. L. Stuart and G. Bras From the Department of Medicine, University of the West Indies, Kingston 7, Jamaica, W.I.

Clinical and epidemiological features of idiopathic cardiomegaly in Jamaica are reviewed, and the high community prevalence of the disorder is shown. Thefrequent occurrence of sudden or unexpected in patients whose earlier electrocardio- grams had shown repeated ventricular ectopic beats has been noted. Common electrocardiographic findings included a high rate of abnormalities usually regarded as indicative of coronary : cardiac , particularly multiple ventricular extrasystoles; and high voltage complexes characteristic of left . The differences and similarities between idiopathic cardiomegaly and coronary heart disease are shown. A possible role for intramuscular lignocaine in the control of the chronic ventricular ectopic rhythms is demonstrated.

There is a statistically significant association between idiopathic cardiomegaly and positive copyright. serological tests for treponemal infection. The are invariably hypertrophied at necropsy. In some hearts the smaller intramuscular show occlusive changes. Their possible nature and significance are discussed.

In I963 we described patients with unex- graphic changes which are commonly associ- plained cardiomegaly seen clinically and at ated with major or minor degrees of coronary http://heart.bmj.com/ necropsy at the University Hospital in insufficiency. Jamaica (Stuart and Hayes, I963). This and subsequent papers showed a high prevalence Subsequent studies of the disorder in Jamaica and noted its occur- Subsequent epidemiological studies of popu- rence in other West Indian communities. The lation samples in Jamaica showed an unex- patients were mainly from the lower income pectedly large number of relatively symptom- groups. In many there was a gradual downhill less subjects with electrocardiographic signs

course with a progressively refractive cardiac usually considered characteristic of ischaemic on September 28, 2021 by guest. Protected failure. In another category the cardiac failure heart disease (Fodor et al., I964). These sur- when present was readily controlled and veys of two communities, one in a rural and death was either sudden or unexpected. the other in a suburban area, showed a higher There were also a number of patients in prevalence of such electrocardiographic ab- whom cardiac hypertrophy was an unexpected normalities than were found in similar sur- finding on examination for unrelated veys in the or Britain. We also reasons. found that cardiothoracic ratios calculated Three clinical types were described, simu- from anteroposterior chest radiographs were lating ischaemic heart disease, valvular heart higher in Jamaica than in Wales (Stuart et al., disease, or constrictive . At I962; Ashcroft and Miall, I969). These find- necropsy the hearts showed a conspicuous and ings are difficult to explain in a community in uniform enlargement with dilatation of all four which coronary and myocardial chambers. Myocardial fibrosis was non-speci- areknown to be uncommon (Robert- fic, and cellular infiltration was mild or absent. son, 1959). Their frequent association, how- In nine of our initial 29 cases there was asso- ever, with symptoms of mild suggested ciated hepatic cirrhosis or fibrosis. There was not only a high community prevalence of an also a high prevalence of the electrocardio- unusual formn of heart disease but also that I88 Stuart and Bras Br Heart J: first published as 10.1136/hrt.33.Suppl.187 on 1 January 1971. Downloaded from these might be early examples of the disorder TABLE I Prevalence of unexplained cardio- characterized in later life by unexplained megaly in amnaican population samples: men cardiomegaly, congestive , and often sudden death. Age No. Rural No. Urban Other studies in Jamaica showed the not radiographed radiographed uncommon association of idiopathic cardio- Unexplained Unexplained megaly with pregnancy, constituting the cardiomegaly cardiomegaly group usually known as peripartal or puer- No. % No. % peral (Stuart, I968). 35-44 69 5 7 go I I Laboratory studies showed that there was 45-54 73 8 II 77 3 4 no higher prevalence of heart antigens in 55-64 73 7 IO 41 3 7 these than was found in rheumatic, hypertensive, or other forms of acquired heart disease (Wilson and Stuart, I970). TABLE 2 Prevalence of unexplained cardio- Coronary during life confirmed megaly in Jamaican population samples: that the major coronary vessels and their main women branches were patent and of normal calibre. In at least two instances it was possible by Age No. Rural No. Urban this means to confirm a diagnosis of coronary radiographed radiographed ischaemia when this could not be differen- Unexplained Unexplained tiated from idiopathic cardiomegaly on clinical cardiomegaly cardiomegaly grounds. Necropsy coronary angiography was No. % No. % also performed in a number of subjects with 35-44 66 2 3 I23 8 7 idiopathic cardiomegaly, again demonstrating 45-54 74 4 5 99 I3 I3 that the major coronary vessels were of nor- 55-64 7I IO 14 7I I2 17

mal calibre. copyright. Long-term clinical, laboratory, and patho- logical study has now added significantly to our knowledge of this disorder. In this paper TABLE 3 Mode of death in 46 patients with we review epidemiological and clinical aspects idiopathic cardiomegaly of patients with idiopathic cardiomegaly. We also give additional details of 46 patients who Mode of death No. %

died during the past five years. http://heart.bmj.com/ Progressive cardiac failure II 24 Findings Sudden or unexpected 25 54 Unknown IO 22 Epidemiological Table i shows the pre- valence of unexplained cardiomegaly on radiography in Jamaican male population samples in a rural and in an urban area. Selec- from progressively refractive cardiac failure. tion was at random in the three decades It is this relatively small group, with its high between and All with 35 64 years. patients morbidity and high hospital admission rate, on September 28, 2021 by guest. Protected cardiac enlargement were clinically examined. which until recently provided most of our Unexplained cardiomegaly was defined as a clinical and hospital experience of this dis- cardiothoracic ratio exceeding 55 with blood order and accounted for our initial and prob- pressures of less than I6o mm. Hg systolic or ably false impression that the disorder was 95 mm. Hg diastolic, or both, and without associated with an excessively high morbidity significant cardiac murmurs on auscultation. rate, that the course was progressive and in- The prevalence of unexplained cardiomegaly exorable, and that the prognosis after the rises with age until it is I0 per cent in the development of heart failure was poor. Sub- rural and 7 per cent in the urban population sequent follow-up studies have shown that samples in the 55-64 decade. even after the initial onset of failure survival Table 2 shows an even higher prevalence for I0 years or more without further decom- in women, rising to I4 and I7 per cent in pensation was not uncommon. similar population samples in the 55-64 In 25 of the 46 patients (54%) death was decade. sudden or unexpected and not due to con- gestive failure, which when present had been Mortality statistics Table 3 shows the reasonably well controlled. The importance of mode of death in the 46 patients who died. this group in the assessment of the mortality In II (24%) death appeared to result solely from this disorder cannot be overemphasized. Prognosis of idiopathic cardiomegaly in Jamaica I89 Br Heart J: first published as 10.1136/hrt.33.Suppl.187 on 1 January 1971. Downloaded from

In IO patients (22%) information about the TABLE 4 Electrocardiographic abnormalities mode of death was too inadequate for this to in University Hospitalpatients with idiopathic be classified accurately. cardiomegaly Electrocardiographic findings Table 4 Electrocardiographic 56 Men aged 62 Womnen aged the electrocardiographic changes in abnormalities 2I-64 years 20-64 years analyses (mean 54 years) (mean 5I years) 56 men and 62 women seen at the Univer- sity Hospital in Jamaica with idiopathic No. % No. % cardiomegaly. There was a high rate of ST-T changes 9 I69 electrocardiographic abnormalities commonly 9 regarded as characteristic of coronary artery QS complexes 5 >36 5 8 50 Left bundle-branch block 6 II 17 271 disease (ST-T changes, QS complexes, and Right bundle-branch block Io i8 4 6 left bundle-branch block). One or other of Ventricular extrasystoles I2 2I 15 24 these changes was found in 36 per cent of Atrial 9 i6 7 II men and 40 per cent of women. Cardiac Left ventricular hypertrophy 24 42 20 32 arrhythmias, particularly multiple ventricular extrasystoles, were common, and were found in 2I per cent of men and 24 per cent of women. The classification of multiple ventricular TABLE 5 Electrocardiographic abnormalities extrasystoles was made when premature beats in relation to mode of death occurred on any one electrocardiographic tracing at more than five per minute. High Mode of death and Electrocardiographic abnormality voltage complexes considered characteristic No. of patients of left ventricular hypertrophy were also ST-T Bundle- Left Ventricular Atrial common. These occurred in 42 per cent of changes branch ventricular extra- fibrillation men and 32 per cent of women. and QS block hyper- systoles or other Table 5 gives the electrocardiographic find- items trophy No. % copyright. ings in relation to the mode of death in the 4I Progressive cardiac of the 46 patients in whom an electrocardio- failure I0 3 4 3 I 10 3 gram was available for study. It is seen that Sudden 23 I 6 3 I3 57 5 there is a high prevalence of arrhythmias, Unknown 8 I 5 I 5 63 2 particularly ventricular extrasystoles, and Total 41 5 I5 7 1I9 47 I0 that these ventricular extrasystoles were

especially common in patients who had died http://heart.bmj.com/ suddenly or unexpectedly, having been pre- sent in I3 of the 23 patients (57%) so classi- rence of sudden death, all suggested similari- fied, and also in 5 of the 8 (63%) whose mode ties with ischaemic heart disease occurring on of death could not be determined. a basis of major . Table 6 summarizes the similarities and Clinical High prevalence rates of electro- differences between idiopathic cardiomegaly cardiograms fulfilling the criteria for left ven- and coronary heart disease. The age at diag-

tricular hypertrophy are in keeping with the nosis is similar in both disorders except that on September 28, 2021 by guest. Protected conspicuous left ventricular hypertrophy com- idiopathic cardiomegaly is not uncommonly monly seen clinically, and with the increased diagnosed in premenopausal women. It is of heart weights invariably found at necropsy. interest that of 13 women with idiopathic Hearts enlarged to this extent on the basis cardiomegaly below the age of 40 years, ii of coronary artery disease do not normally (85%) were recognized because of unex- show such high voltage potentials on plained congestive cardiac failure occurring electrocardiographic examination. These soon after delivery and were classified as observations also confirm our impression that peripartal. hypertrophy is the dominant lesion in these The onset of symptoms is usually sudden in hearts and that wall-cavity ratios are high, coronary heart disease; it is slow and progres- and probably higher than those seen in con- sive in idiopathic cardiomegaly. Clinical car- gestive cardiomyopathy in other areas. diac enlargement is a late finding in the The electrocardiographic patterns com- history of coronary heart disease, and the monly associated with ischaemic heart disease, initial finding in patients with unexplained the high prevalence of multiple ventricular congestive failure. The prognosis after the extrasystoles, their common association with heart is enlarged and after the onset of heart symptoms of mild angina and with the occur- failure is usually poor in coronary heart 9go Stuart and Bras Br Heart J: first published as 10.1136/hrt.33.Suppl.187 on 1 January 1971. Downloaded from

TABLE 6 Comparison of coronary heart disease and idiopathic cardiomegaly in Jamaica

Coronary heart disease Idiopathic cardiomegaly Age group Middle age and elderly Similar, but not uncommon in pre- menopausal women Onset Usually sudden Slow, progressive Angina Common: obtrusive Common: mild Clinical cardiac enlargement Late finding Initial finding Prognosis after cardiac enlargement Poor Good Prognosis after onset of cardiac failure Poor Good Heart weight Variable Invariably increased Left ventricular hypertrophy on electro- cardiogram Uncommon Common Conduction defects Common Common Ventricular ectopics Common Common Sudden death Common Common

disease, and commonly good in -idiopathic ectopic rhythms which characterize the car- cardiomegaly. Heart weight is variable in diomyopathies, and possibly to the reduction patients dying with coronary heart disease, of the high mortality rates with which they but invariably increased in the idiopathic are associated. They may also be of value in cardiomegalies. Electrocardiographic evidence other conditions characterized by ventricular of left ventricular hypertrophy is uncommon arrhythmias, a striking example of which, of in coronary heart disease with or without course, is acute . Lown cardiac enlargement. It is common in idio- and Vassaux (I970), for instance, have recently pathic cardiomegaly. Conduction defects, suggested that 50 mg. lignocaine should be

ventricular ectopic beats, and sudden death given intravenously to a patient with acute copyright. are common in both conditions. myocardial infarction immediately before transport to a hospital, and that this should Lignocaine trial It was the similarities be carried out even if no ectopic beats are with coronary heart disease and the suggestion detected. Our findings suggest that the that the majority of might have been intramuscular route, by its longer duration of of dysrhythmic origin which suggested a line action, may be a more effective method for pre-

of approach to treatment and a possible means venting the emergence of ventricular arrhyth- http://heart.bmj.com/ for reducing the mortality by suppressing the mias during the period normally required for rates of emergence of fatal tachyarrhythmias, the transportation, examination, and admis- as has been achieved in coronary heart disease. sion of the coronary patient to hospital. We have tested the effectiveness and dura- tion of action of intramuscular lignocaine in Serological tests for treponemal infec- reducing the number of ventricular extra- tion Fig. i compares the results of the systoles. We thought that this would avoid Venereal Disease Research Laboratories test many of the impracticalities of the intra- on September 28, 2021 by guest. Protected venous route and produce a more sustained effect. Scott and his colleagues (I968) have shown TABLE 7 Ventricular extrasystoles after that intramuscular lignocaine can achieve intramuscular lignocaine plasma levels considered effective for the sup- pression of arrhythmias, and that these levels Average No. of extrasystoles per minute are quickly reached and may be maintained for a considerable of Patient I hour Hours after injection period time. The dose No. before of choice seems to be 2oo mg., which achieves injection + 2 4 6 adequate but not dangerously high serum levels of lignocaine. I 10 2 3 The effects of intramuscular lignocaine in 2 12 0 0 - 3 7 I 2 - the first nine patients we studied are shown in 4 8 I 2 - Table 7. It is seen that this not only reduces 5 5 2 2 considerably the number of ventricular extra- 6 5 0 0 6 systoles but that this reduction can persist for 7 I O - several 8 8 2 I - hours. These data suggest an approach 9 II 6 2 I 4 to the treatment of the chronic ventricular Prognosis of idiopathic cardiomegaly in Jamaica I9I Br Heart J: first published as 10.1136/hrt.33.Suppl.187 on 1 January 1971. Downloaded from

for treponemal infection in the following %PO~SITIVE 74 categories of patients: (i) an urban population who have lived all their lives in the town and never in a rural area; (2) a group of patients who are attending our hypertensive clinic and who are considered characteristic of patients attending the outpatient clinics at the University Hospital; (3) patients from a rural area (Lawrence Tavern) where the transmission rate for yaws was known to have been high until recent years; and (4) the seventy-nine patients with cardiomyopathy (39 male and 40 female) in whom serological tests for treponemal infection were available. M F M F M F M F Details of groups (i) and (2) are reproduced URBAN EP. CUNIC RURAL IDIOPATHIC from the study of Ashcroft and co-workers UNIV. HOSP CARDIOMEGALY (I967). There is a highly significant associa- FIG. I Venereal Disease Research Labora- tion of cardiomyopathy with a positive ser- tories tests in certain populations. See text. ology when compared with the urban group or the hypertensive outpatient population. Seropositive rates were also higher in the because of the high prevalence of arrhythmias cardiomyopathies than in individuals from a and conduction defects. The selected rural area where high seropositive showed an increase in fibrous tissue in these rates were known to occur. cases, though in none was there complete This association does not necessarily estab- destruction. The atrioventricular node showed lish an aetiological relationship with yaws or similar changes with some fibrosis in these syphilis. However, studies to confirm and hearts and haemorrhage and round- infil- extend these observations are clearly indi- trate in one. copyright. cated. Pathology FIG. 2 Globular-shaped heart weighing Macroscopical appearances Details of the II40 g. pathology have been given in a recent paper (Campbell et al., 197I). Gross cardiomegaly

was present in the 2I cases studied at necrop- http://heart.bmj.com/ sy, the average heart weight being 675 g. Two hearts actually weighed more than a kilogram each. The characteristic globular appearance is seen in Fig. 2. Dilatation and hypertrophy of all chambers was the rule. The myocardium was usually of normal consistency. In only two hearts was

there easily discernible fibrosis in the gross on September 28, 2021 by guest. Protected specimen. Endocardial thickening was not a constant feature; it was mild and was usually limited to irregular mild fibrosis in the out- flow tract. In four hearts small mural thrombi were seen in the apices of both ventricles. The valves were in all cases within normal limits. The larger coronary vessels were free from atheromatous narrowing and in the majority of cases presented a normal picture when opened longitudinally. Coronary angio- graphy was performed on 7 hearts. Fig. 3 is a typical result. The vessels showed a smooth outline with no evidence of occlusion or narrowing.

., t m ~ Conduction system The conduction sys- 6 'I!...... 2, 3. 4, ...Ai.- .tS.'. .tI.I 4 tem was examined carefully in serial sections "kJ...... & 192 Stuart and Bras Br Heart J: first published as 10.1136/hrt.33.Suppl.187 on 1 January 1971. Downloaded from

The bundle of His showed changes similar to those seen in the atrioventricular node. The left bundle-branch was the site of widespread lesions in 13 of the I5 hearts. The right bundle showed patchy fibrosis in 4 cases, and necrosis in one. The intramuscular coronary arteries In 3 of the hearts examined by serial sections it was noticed that many intramural vessels ex- tending over several millimetres showed thick- ening of their walls. There was consequently a narrowing of the lumen, very obvious in some instances. The nature of this lesion is fully described in our previous paper. Fig. 4 and 5 are illustrative. It should perhaps be re-emphasized that these changes in the intramural vessels oc- curred without a concomitant lesion in the large coronary arteries. Histological changes in the myocardium were usually absent or non-specific. Japanese workers have recently described theoccurrence ofunexplained cardiac failure in patients who were found to have normal main FIG. 3 An angiogram of the heart showing coronary artery systems but with occlusive the smooth uniform coronary arteries. abnormalities in the intramuscular vessels between 8o and 500 ,um. in diameter (Donomae copyright. et al., I962). They suggested that the lesions in these vessels may lead to chronic cardiac failure without anginal pain or other symp- FIG. 4 Thickening of the wall of a small toms. They further suggest that in Japan, blood vessel due mainly to medial hypertrophy. with its low rate of coronary , (H. and E. x 200.) presumably because of a low diet, coronary arteriolar sclerosis could be an important FIG. 5 Thickening of the wall of an intra- http://heart.bmj.com/ cause of the silent type of coronary heart mural blood vessel due mainly to intimal disease which is so common in that country. thickening. (Elastic van Gieson. x 200.) Our findings also suggest that in Jamaica, with its comparable low rate of athero- sclerosis, sclerosis of the smaller coronary vessels may be the cause of a type of coronary heart disease presenting clinically as unexplained cardiac enlargement and cardiac on September 28, 2021 by guest. Protected failure. The implication is strong that the back- ground of some cases of idiopathic cardio- megaly may bemyocardialischaemia occurring at a gradual and insidious pace and prob- ably diffusely involving a smaller category of coronary vessel. Although it is unlikely that this would en- tirely explain the high prevalence of the car- diomyopathies in Jamaica, it may provide useful additional information about at least a number of these unusual cases. The high association with a positive serology may also provide an additional avenue for further study. Although there are still many gaps in our knowledge, our opportunities for prolonged and detailed clinical and epidemiological study Prognosis of idiopathic cardiomegaly in Jamaica 193 Br Heart J: first published as 10.1136/hrt.33.Suppl.187 on 1 January 1971. Downloaded from have already added significantly to our know- Donomae, I., Matsumoto, Y., Kokubu, T., Koide, R., Kabayashi, R., Ikegami, H., Ueda, E., Fuji- ledge of this disorder particularly as seen in sawa, T., and Fujimoto, S. (I962). Pathological Jamaica and other West Indian territories. studies of coronary atherosclerosis: especially of sclerosis of intramuscular coronary arteries. Japanese Heart_Journal, 3, 423. This work was supported by grants from the Fodor, J., Miall, W. E., Standard, K. L., Fejfar, Z., World Health Organization and the British and and Stuart, K. L. (I964). Myocardial disease in a Canadian Heart Foundations. It is a pleasure to rural population in Jamaica. Bulletin of the World record our thanks to Mrs. Mareen Roberts and Health Organization, 31, 321. Mrs. Phyllis Gibbs, research assistants, and to Lown, B., and Vassaux, C. (I970). Lidocaine in acute successive house-officers and registrars for their myocardial infarction. American Heart Journal, 76, assistance. The information in Tables 587. dedicated and ischae- i and 2 was provided by courtesy of Dr. W. E. Robertson, W. B. (I959). Atherosclerosis Research mic heart disease: observations in Jamaica. Lancet, Miall, Director of the Epidemiological I, 444. Unit, Jamaica. Scott, D. B., Jebson, P. J., Vellani, C. W., and Julian, D. G. (I968). Plasma levels of lignocaine after intramuscular injection. Lancet, 2, I209. Stuart, K. L. (I968). Cardiomyopathy of pregnancy and the puerperium. Quarterly Journal of Medicine, References 37, 463. Ashcroft, M. T., and Miall, W. E. (I969). Cardio- , and Hayes, J. A. (I963). A cardiac disorder of thoracic ratios in two Jamaican communities. unknown aetiology in Jamaica. Quarterly Journal American Journal of Epidemiology, 89, i6i. of Medicine, 32, 99. -, -, Standard, K. L., and Urquhart, A. E. , Miall, W. E., Tulloch, J. A., and Christian, (I967). Serological tests for treponemal disease in D. E. (I962). Dilatation and unfolding of the aorta adults in two Jamaican communities. British in a Jamaican population. British Heart J7ournal, Journal of Venereal , 43, 96. 24, 455. Campbell, M., Summerell, J. M., Bras, G., Hayes, Wilson, M. E., and Stuart, K. L. (1970). Immunologi- J. A., and Stuart, K. L. (I97I). The pathology of cal studies on leakage of heart antigens in Jamaican idiopathic cardiomegaly in Jamaica. British Heart cardiomyopathies. West Indian Medical3Journal. In 7ournal 33, I93. the press. copyright. http://heart.bmj.com/ on September 28, 2021 by guest. Protected