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392 Br Heart J 1992;68:392-7 Efficacy of , , and in the

treatment of right ventricular in Br Heart J: first published as 10.1136/hrt.68.10.392 on 1 October 1992. Downloaded from patients without overt cardiac abnormality

Jaswinder S Gill, Davendra Mehta, David E Ward, A John Camm

Abstract associated with a clinically normal heart Objective-A comparison ofthe efficacy can be suppressed by flecainide, sotalol, of verapamil, sotalol, and flecainide to or verapamil. In individual patients suppress right sotalol was the most frequently effective (VT) in patients with a clinically normal drug (effective in > 89% of patients) and heart. is a suitable choice for first line Design-Patients underwent treat- treatment. ment serially with verapamil (360 mg daily), sotalol (240 or 320 mg daily), and (Br Heart J 1992;68:392-7) flecainide (200 or 300 mg daily), (the Most patients presenting with ventricular larger dose was for patients heavier than tachycardia (VT) have easily detectable 80 kg) to suppress tachycardia. Each underlying cardiac disease, such as coronary drug was given orally for five half lives artery disease, cardiomyopathy, and valvar or before testing. congenital heart disease. Five to 10 percent of Patients-23 patients with right VT patients, however, are reported to have no associated with a clinically normal heart underlying heart disease as suggested by non- were studied. invasive and invasive assessment of left Outcome measures-The effects of ventricular function and coronary anatomy.`-3 drug treatment were examined by the These patients do, however, exhibit variable number of ventricular events on 24 hour degrees of histological abnormality on cardiac Holter monitoring, and the ability of interstitial and tachycardia to be induced by treadmill biopsy (60-90%), including perivascular fibrosis and vascular sclerosis, http://heart.bmj.com/ exercise testing (Bruce protocol) and acute or subacute myocarditis, and an increase programmed ventricular stimulation in interstitial adipose tissue.' The reports on (Wellens protocol), compared with drug the prognosis of such patients are contradic- free baseline tests. tory.7' Although most authors suggest that Setting-Patients were studied in a prognosis is good, there are several who tertiary referral centre. indicate that this may be a more common Results-All three drugs suppressed cause of sudden death in young patients than ventricular salvos ( > 3, < 5 consecutive previously proposed.'12 Even though treat- on September 27, 2021 by guest. Protected copyright. ventricular premature contractions) ment may not be indicated on prognostic (p < 0-01) and VT (p < 0 05) on Holter grounds, many of these patients are severely monitoring and did not differ statistically symptomatic and require treatment to control in efLect. Exercise induced VT was also the tachycardia. Most of the treatment data on suppressed by all three drugs (p < 0-01), these patients consist of short case series and and of these sotalo: was the most effective anecdotal reports,'1'5 and there has been although this was not statistically no adequate study of the efficacy of anti- significant (14/23 inducible when drug arrhythmic drugs in controlling this form of free, 4/23 on flecainide, 2/23 on sotalol, VT. Our study examines and compares the 5/23 on verapamil). Sustained and non- efficacy of flecainide, sotalol, and verapamil sustained VT induced by programmed in the treatment of VT in patients with stimulation was also suppressed by the apparently normal hearts. Department of three drugs (p < 0-01) and again sotalol Cardiological was the best of these though the differ- Sciences, St George's Hospital Medical ences did not achieve statistical sig- Patients and methods School, London nificance (17/23 inducible when drug free, PATIENTS J S Gill 4/17 on flecainide, 2/17 on sotalol, and 6/17 Twenty three patients with a clinical history of D Mehta of sustained VT 30 s) and a clinically normal D E Ward on verapamil). Proarrhythmic effects (> A J Camm drugs were found in a few patients. heart were studied. These patients came from a Correspondence to There was no difference in the efficacy of group of 26 consecutive patients with right Dr J S Gill, the drugs in patients with histological. ventricular tachycardia seen at our institution Departnent of Cardiological Sciences, St George's abnormalities of the myocardium when over two years. Two patients had had at least Hospital Medical School, compared with those of normal two of the drugs used in this study on a London SW17 ORE. histology. previous occasion and these were clinically Accepted for publication 8 April 1992 Conclusions-Ventricular tachycardia ineffective. One patient was on . Efficacy offlecainide, sotalol and verapamil in the treatment ofright ventricular tachycardia in patients without overt cardiac abnormality 393

These patients were excluded from our study. >3 beats to <30 s and terminating sponta- Patients gave informed consent to the protocol neously without haemodynamic compromise). for drug testing and were enrolled in the study Despite the non-sustained nature of the ar- on the basis of the following criteria: (a) rhythmia in many patients, all patients were Br Heart J: first published as 10.1136/hrt.68.10.392 on 1 October 1992. Downloaded from patients had no history of ischaemic heart severely symptomatic and merited treatment disease or congenital cardiac abnormality. (b) on this basis. The mean (SD) rate of tachy- All had chronic ventricular cardia was 212 (37-8) beats/min. Patients documented on multiple electrocardiographic underwent echocardiographic examination, leads either during a spontaneous episode or and all had normal left ventricular function and during an exercise test. Arrhythmia was defined dimensions. The findings for the right ven- as chronic when there was a minimum of two tricular examination have been published documented episodes at least one month apart. already in a larger group of such patients.'6 (c) Patients had a normal clinical examination, Signal averaged was per- normal chest radiograph (cardiothoracic ratio formed on admission and patients also under- < 50%), and normal resting electrocardiogram went full electrophysiological evaluation before (apart from T wave abnormalities). Patients entry in the study. Ventricular endomyocardial with intraventricular conduction abnor- biopsies were taken and subjected to routine malities, left or right ventricular hypertrophy, histopathological studies. and prolongation of the QT interval were excluded. (d) No patient had angiographic DRUG TREATMENT evidence of , reduced Many of the patients had already received of the left ventricle, or abnor- treatment for their tachycardia, but in all, mality of regional wall motion during left treatment was stopped at least 72 hours before ventricular cineangiography as assessed by two admission and evaluation of the patient in a independent observers. drug free state. No patient had received All patients had episodes ofpalpitation, eight amiodarone within three months of assess- had experienced syncope and an additional 11 ment. Patients received verapamil (360 mg had had presyncope. The duration of symp- daily in three divided doses), sotalol (240 mg or toms ranged from two weeks to 20 years. The 320 mg), and flecainide (200 or 300 mg) daily in documented spontaneous arrhythmia was of divided doses. The larger doses were given to right ventricular tachycardia (left bundle patients Who weighed more than 80 kg. The branch block-like morphology) in all 23 drugs were given serially and maintained for a patients (QRS complex > 120 ms and minimum of five half lives to allow stable predominently negative in lead VI, fig). The concentrations to be reached before evaluation frontal plane axis ofthe clinical tachycardia was of efficacy. At least five half lives were allowed defined from the limb leads as leftward between drugs to wash out the previous drug. (<-30°), rightward (> + 900), or normal This is therefore an open, non-randomised, (-30° to + 90°) from the vector perpendicular fixed sequence drug study. This design was http://heart.bmj.com/ to the lead with the most isoelectric QRS accepted because of clinical and administrative complexes. The history of was limitations. A fully randomised double blind suggestive of sustained episodes of VT in all study would have required matching tablets to patients with either documented arrhythmia, be given in random order. Five half lives of the syncope, or presyncope. The episodes of clini- drug with the longest half life would have been cal tachycardia were documented as sustained necessary at each stage to load and wash out the

in 10 patients (spontaneous arrhythmia of drugs. This would result in a prohibitively long on September 27, 2021 by guest. Protected copyright. uniform QRS morphology lasting >30 s or admission for the patient. The use of the drugs requiring termination because of haemo- with the shorter half lives initially allowed dynamic compromise) and non-sustained in rapid loading and washout of the drug, reduc- the rest (uniform broad QRS complexes lasting ing the time necessary for the study.

aVR vi V4 EVALUATION OF TREATMENT Patients were evaluated with Holter monitor- ing, exercise testing, and programmed ven-

YAYYAA}A tricular stimulation when drug free and on each of the three drug treatments. For drug free had been on no for V2 V5 evaluation, the patient drugs 11 aVL at least five days. On each drug, the patient was specifically asked for any subjective side effects experienced during that treatment. WXkAAx~vwvWavyyyl(vfiAkAAMA Holter monitoring Holter tapes (Tracker, Reynolds Medical Ltd, III aVF V3 V6 Hertford) were applied for 24 hours and analysed on a commercially available system (Pathfinder III, Mk2, Reynolds Medical). The AAMAAAkMAA4AVk~YY$AAAAAJV)T Holter tape analysis defined the number of s normal complexes, ventricular extrasystoles, couplets, salvos ( > 3, < 5 consecutive ven- tricular premature contractions (VPCs)) and Right ventricular tachycardia with an inferior axis, typical of theform of tachycardia present in our patients. episodes ofVT ( > 5 VPCs at > 120 beats/min). 394 Gill, Mehta, Ward, Camm

These were then standardised to a one hour stages of Wellens protocol, was recording period before statistical analysis by infused at a rate of 1-4 ig/min to increase the non-parametric methods. The percentage sup- sinus rate by at least 30% or to 120 beats/min pression of ventricular extrasystoles on each (whichever was less) and the programmed Br Heart J: first published as 10.1136/hrt.68.10.392 on 1 October 1992. Downloaded from treatment compared with those when drug free ventricular stimulation was repeated. The test was also calculated. The number of patients in was considered positive if VT of the same whom >75% and >90% suppression of configuration and axis as the clinically Holter events was achieved is also given. documented tachycardia was induced. If other configurations of tachycardia were induced, Exercise testing then the test was considered non-specific and Exercise tests and programmed ventricular negative. Inducible non-sustained VT was stimulation (see next section) were performed defined as ventricular extrasystoles of uniform two to four hours after the last dose ofthe drug. QRS configuration, rate > 120 beats/min, last- Treadmill exercise testing was performed with ing > 5 beats and < 30 s, and terminating the Bruce protocol'7 and the electrocardiogram spontaneously without haemodynamic was monitored during the test with apparatus compromise. The tachycardia was defined as from Marquette Electronics (Milwaukee, sustained if it lasted > 30 s or required termin- USA). Patients exercised until maximal ation because of haemodynamic compromise. predicted heart rate was achieved, became If the study did not induce VT in the drug free limited by dyspnoea and , or had sus- state, even after the use of isoprenaline, a tained VT. Electrocardiographic recordings further study was performed the next day. If in (leads II, V2, and V5) were monitored during this study, VT could not be induced after the test and for a minimum of 10 minutes after giving isoprenaline and 120 ,ug , fur- exercise or until the cardiac rhythm returned to ther programmed stimulation was not perfor- the pre-test sinus rate. Blood pressure and the med during the evaluation of the drugs. 12 lead electrocardiogram were recorded before, and immediately after the exercise and Statistical analysis every three min during exercise and recovery. Statistical analysis was performed with the Exercise provoked tachycardia was defined as SPSS package (SPSS Inc, Chicago, USA). the presence of five or more consecutive ven- Inducibility of the tachycardia was assessed tricular extrasystolic depolarisations occurring when drug free and on each of the drug during or after exercise and was considered treatments for each patient. Differences be- sustained if it lasted 30 seconds or longer. tween the results when drug free and during Changes in ST segment were monitored treatment with the three drugs were compared throughout the test, but no patient had any by analyses ofvariance, contingency tables, and changes to suggest ischaemia. non-parametric analyses as appropriate. http://heart.bmj.com/ Programmed ventricular stimulation Programmed ventricular stimulation was per- Results formed after an overnight fast. After giving Twenty three patients (12 men) mean age 42 6 10 ml of 1% lignocaine for local anaesthesia, (SD 11 8; range 21-69) years were studied. All multipolar electrode catheters were inserted patients had right VT of which 11 had a through the subclavian vein into the atrial rightward axis, four had a leftward axis, and appendange and right ventricular apex. The eight had a normal axis. The mean (SD) doses

intracardiac electrograms and surface electro- ofthe drugs given were 233 (64 3) mg flecainide, on September 27, 2021 by guest. Protected copyright. cardiograms were displayed simultaneously on 270 (48 2) mg sotalol, and 360 (0 0) mg a multichannel oscilloscope and recorded on a verapamil. Table 1 shows the results of the multichannel inkjet recorder (Siemens Min- Holter monitoring. There was a large gograph, Solna, ) at a paper speed of individual variability in the number of ven- 25-100 mm/s. Ventricular stimulation was tricular extrasystoles in the 24 hours, but the performed with a Medtronic 5326 program- effects of the different drug treatments were mable stimulator (Medtronic, Minneapolis, fairly consistent. All three drugs resulted in USA) with 1 8 ms rectangular pulses at twice partial suppression ofventricular extrasystoles, diastolic threshold. Programmed ventricular couplets, salvos, and episodes of VT on Holter stimulation was performed by the Wellens monitoring. The numbers of patients with protocol.'8 Briefly, one premature ventricular 90% and 100% suppression of VT on Holter stimulus was introduced after every eight monitoring were similar on the three drugs paced or conducted ventricular QRS com- (table 1). The drugs did not differ statistically in plexes beginning late in diastole and then at efficacy. The comparative ineffectiveness of progressively closer coupling intervals until flecainide in reducing Holter monitored events ventricular refractoriness was encountered. contrasts with previous reports of its efficacy in The extra stimulus coupling interval was then other types of VT. An increase in the hourly increased by 20 ms, out of ventricular refrac- episodes of VT > 150% over drug free values toriness and a second extra stimulus was was seen in one patient onflecainide, one patient introduced. The process of diminishing coup- on sotalol, and two patients on verapamil. ling intervals was repeated for the second and Table 2 gives the results of exercise testing then the third extra stimulus until a total of The time to the end ofthe test, whether this was three extrastimuli had been introduced. Paced by exhaustion, achievement of the maximum drive cycle lengths of 600, 500, and 400 ms heart rate, or start of tachycardia, was not were used. If VT was not induced by the 12 affected by any of the treatments. The time to Efficacy offlecainide, sotalol and verapamil in the treatment of right ventricular tachycardia in patients without overt cardiac abnormality 395

Table I Results of Holter monitoring and the number ofpatients with suppression of Holter monitored events when drugfree and on three treatments

Drugfree Flecainide Sotalol Verapamil Br Heart J: first published as 10.1136/hrt.68.10.392 on 1 October 1992. Downloaded from (n = 21) (n = 21) (n = 21) (n = 21) p Value VES/h 741.7 269-3 446.4 487 7 007 Couplets/h 28.8 19 9 8.3 7-5 0-06 Salvos/h 4-9 0-4 9-3 4.8 0 007 VT/h 12 8 01 28 3 3 004 No of patients with > 75% suppression of: VES/h 7 5 6 Couplets/h 10 9 8 Salvos/h 9 9 7 VT/h 10 10 9 No of patients with > 90% suppression of: VES/h 3 4 5 Couplets/h 9 7 6 Salvos/h 9 9 6 VT/h 10 10 9 No of patients with 100% suppression of: VT/h (totaln = 13 9 9 8 Data are on 21 patients because of tape failures on two. VES, ventricular extrasystoles.

the end of the test on sotalol did not differ and non-sustained (2/7 v 6/7) these differences significantly from the other treatments al- were not significant (p = 0 4 and p = 0-9). though it was a little lower. Fourteen patients More patients were inducible (6/17) and sus- developed exercise induced VT when drug free tained (4/7) on verapamil when compared with and in four the arrhythmia was sustained. All sotalol (p = 0 07 and p = 0-8 respectively). If three drugs resulted in some suppression of the induction and suppression of only sus- exercise induced VT and there were only two tained VT was considered, the results were episodes of sustained tachycardia, one on similar and all three drugs suppressed in- sotalol and one on verapamil. Two patients on ducible VT, but did not achieve statistical flecainide, one patient on sotalol, and three significance because of the small numbers. The patients on verapamil had VT at exercise on the stage of the Wellens protocol at which drug when there had been no arrhythmia when tachycardia was induced was also increased by drug free (table 3). This may be due to the all three treatments (p < 0-01) but no dif- inherent variability of induction of arrhythmia ference could be shown between the treatments with exercise or a genuine proarrhythmic effect. (p = 0 4; data not presented). Two patients on Sotalol was the best of the three drugs but this flecainide, one patient on sotalol, and three difference was not significant (p = 0 4). The patients on verapamil developed sustained VT stage at which tachycardia was induced was not on the drug, whereas VT in these patients had significantly influenced by the treatments been non-sustained when drug free. In one http://heart.bmj.com/ (p = 0 4 for all treatments), though more patient the induced tachycardia was faster on patients had tachycardia during the test rather sotalol than the drug free arrhythmia and than in recovery on flecainide and verapamil required , whereas two of the when compared with sotalol. induced on verapamil were Tachycardia was induced by programmed haemodynamically unstable, requiring ventricular stimulation in 17 patients when cardioversion. Side effects from the drugs in all cases only tachycardia that was included five patients who experienced dizzi-

drug free, on September 27, 2021 by guest. Protected copyright. of similar configuration and axis to the clinical ness on flecainide and six said they were tired on tachycardia was considered relevant. In one sotalol. Two patients had some tiredness on patient the clinical tachycardia was only verapamil. Individual patients responding to stimulated after isoprenaline infusion (2 ig/ one drug, in general responded to the other min) when drug free and the same dose of drugs and there was no difference in the efficacy isoprenaline was used on all the subsequent of the drugs in patients with abnormal his- trials with antiarrhythmic treatment. In seven tology compared with those with normal his- patients, the induced tachycardia was sus- tology in any of the three tests. tained. Inducible tachycardia was rendered non-inducible by all three drug treatments in over 50% of the patients (table 4). Although Discussion flecainide when compared with sotalol made The results suggest that right VT associated fewer patients non-inducible (13/17 v 15/17) with a normal heart responds well to the drugs

Table 2 Results of exercise testing when drugfree and with three drug treatments Table 3 Number ofpatients with or without ventricular tachycardia (VT) during exercise when drugfree and in Drugfree Flecainide Sotalol Verapamil three treatment groups (n = 23) (n = 23) (n= 23) (n = 23) Flecainide Sotalol Verapamil Exercise tolerance 599 627 617 643 (SD) (199) (169) (201) (153) No VT baseline Non-inducible* 10 20 22 19 NoVTdrug 7 8 6 Inducible* 14 4 2 5 VT baseline Sustained tachycardia* 4 0 1 1 No VT drug 12 13 12 p Valuet 0 007 <0 001 0-02 VT baseline VT drug 2 1 2 *Number of patients. No VT baseline tFor differences between the drug treatments and drug free for induction of ventricular VT drug 2 1 3 tachycardia (VT). 396 Gill, Mehta, Ward, Camm

Table 4 Results ofprogrammed stimulation when patients were drugfree and in each of siderable logistic difficulties. The study does three treatments groups not include drug concentrations and although Flecainide Sotalol Verapamil sotalol and flecainide have somewhat long half

Drugfree Br Heart J: first published as 10.1136/hrt.68.10.392 on 1 October 1992. Downloaded from (n = 23) (n = 17) (n = 17) (n= 17) lives, that of verapamil is variable. Further- Non-inducible* 6 13 15 11 more, verapamil is subject to substantial first Inducible* 17 4 2 6 pass metabolism. To minimise variation due to Sustained tachycardia* 7 2 1 4 Mean rate of tachycardiat these factors, exercise tests and programmed (beats/min) 241-0 213-3 230-0 220-0 stimulation were performed two to four hours p Value: 0 004 <0 001 0 03 after the last drug dose. The tests used for *Number of patients; trate during induced sustained VT; tp value for differences between drug evaluation of drug efficacy in this study are not treatment and drug free for induction of tachycardia. subject to bias, and adequate periods were allowed for the drug concentrations to equilibrate and wash out. This study, despite tested in this study. Although differences be- its deficiencies, is the only systematic study of tween the drugs did not achieve significance, drug efficacy in the suppression of VT sotalol was generally the most effective. associated with a normal heart. A study of this Earlier studies of the treatment effects of nature does, therefore, provide valuable infor- drugs in VT associated with a normal heart mation allowing appropriate choice of drug for are few. Buxton et al examined the effect of patients with this form of tachycardia. antiarrhythmic drugs upon spontaneous ar- All patients had left bundle branch block- rhythmia in right ventricular tachycardia and like morphology VT, which can usually be reported that class 1 antiarrhythmic agents mapped to the right ventricle3 and is often from (, ) suppressed all VT the region of the outflow tract when associated in 9/16 patients and were ineffective in seven.3 with a rightward or normal axis. Electro- suppressed spontaneous VT in 8/ physiological mapping of the tachycardia of 16 patients whereas verapamil was effective in patients in this study was performed in eight 1/4. Amiodarone was used in 2/4 patients and cases and this showed the origin of the tachy- two were not suppressed by any form of drug cardia to be in the right ventricle or the septal treatment. Ventricular tachycardia inducible aspect of the right ventricular outflow tract in by programmed stimulation was rendered non- seven subjects and in the free wall ofthe outflow inducible in 8/9 patients by class 1 agents, in tract in one. Our experience with these forms of 3/6 patients by propranolol, and in 0/4 patients tachycardia is similar to that of other groups in by verapamil. Rahilly et al reported a series of that they are often inducible by exercise and patients with repetitive monomorphic VT as- less frequently by programmed ventricular sociated with a normal heart, which included stimulation.79 patients with VT of right and left ventricular Whether this form of tachycardia requires origin in whom 7/7 patients responded to treatment, and the prognosis of VT associated enacainide. 9 Five other patients received either with a normal heart remain controversial http://heart.bmj.com/ quinidine or propranolol singly, combined, or issues. Many studies suggest that when VT aprinidine. Six patients with right ventricular occurs in association with a normal heart prog- outflow tachycardia reported by Pietras et al nosis is good and the patients do not suffer *were evaluated by serial treadmill testing.'3 In sudden death.278 This contrasts with VT these procainimide, quinidine, and diso- associated with ischaemic heart disease and pyramide were relatively ineffective whereas cardiomyopathy where there is a high mortality VT. There propranolol prevented treadmill provocation of associated with symptomatic are, on September 27, 2021 by guest. Protected copyright. VT in all patients. Similar results were however, several studies reporting that prog- obtained by Brodsky et al where in six patients, nosis of VT in young patients with "normal" treatment with ,B blocker prevented induction hearts may be worse than previously ofVT by exercise and programmed stimulation proposed.' '2 Many of the patients in these and reduced ventricular extrasystoles and VT groups had frank arrhythmogenic right ven- on Holter monitoring.'4 Lemery et al in their tricular dysplasia, and most had right VT. series of VT of right and left ventricular origin Though none of our patients had obvious reported that most patients (48%) were treated evidence of arrhythmogenic right ventricular with either sotalol or a class IC agent, whereas dysplasia, many patients showed evidence of amiodarone was used in 19%, and a calcium endocardial and interstitial fibrosis, and some was used in two patients.9 In a had fatty infiltration ofthe myocardium, which specific study of right ventricular tachycardia, may represent variant forms of this condition. sotalol was reported as effective as were class IC Future studies need to concentrate on the agents, whereas verapamil was effective in only classification of VT associated with a normal one patient.'5 These studies contrast with the heart and the natural history of the tachycardia present report where a single configuration of in these subgroups. In our own series of 40 VT has been studied and preselected drugs patients with VT associated with a normal used at fixed doses. heart followed up for a period of three years, Our study is not a randomised controlled there have been two deaths, one related to trial, and therefore, it is difficult to ascertain surgery for incessent VT, and the other a placebo effects, elements ofbias, and carry over sudden death, presumably related to arrhyth- effects. Although it is straightforward to organ- mia. This mortality is higher than that expec- ise and conduct a study oftwo drugs in a double ted in such a young group of subjects suggest- blind placebo controlled manner, a trial involv- ing that the condition may not be as benign as ing three drugs and a placebo presents con- reported in previous studies. Efficacy offlecainide, sotalol and verapamil in the treatment of right ventricular tachycardia in patients without overt cardiac abnormality 397

Although many patients may be more or less ventricular stimulation appears to be sotalol. symptom free some have severe symptoms and Flecainide and verapamil can be used in cases suffer disabling attacks of palpitation. All the where sotalol has failed. patients in this study had evidence of sustained Br Heart J: first published as 10.1136/hrt.68.10.392 on 1 October 1992. Downloaded from of VT with symptoms of sustained episodes 1 Froment R, Gallavardin L, Cahen P. Paroxysmal ventricular palpitation, syncope, or presyncope related to tachycardia: a clinical classification. Br Heart J 1953;15: arrhythmia. Thus although some patients with 172-8. 2 Chapman JH, Schrank JP, Crampton RS. Idiopathic ven- only non-sustained episodes of palpitation may tricular tachycardia. An intracardiac electrical, hemo- assessment of six Am not require drug treatment, many will have dynamic and angiographic patients. JMed 1975;59:470-80. disabling symptoms necessitating treatment. 3 Buxton AE, Waxman HL, Marchlinski FE, Simson MB, and the clinical of other Cassidy D, Josephson ME. Right ventricular tachycardia: Our study experience Clinical and electrophysiological characteristics. Circula- groups suggest that these tachycardias are tion 1983;68:917-27. suppressed by the ,B blocking and class III 4 Strain JE, Grose RM, Factor SM, Fisher JD. Results of endomyocardial biopsy in patients with spontaneous ven- activity ofsotalol, the class IC effect offlecainide tricular tachycardia but without apparent heart disease. and the class IV action of In this Circulation 1983;68:1171-81. verapamil. 5 Sugrue DD, Holmes DR, Gersh BJ, Edwards WD, study the effect of a pure ,B blocking McLaran CJ, Wood DL, et al. Cardiac histologic findings of agent was not but there are three in patients with life threatening ventricular examined, unknown origin. JAm Coll Cardiol 1984;4:952-7. previous reports of its efficacy.'3"420 Overall, 6 Metha D, McKenna WJ, Ward DE, Davies MJ, Camm AJ. in sotalol was the most effective drug in suppres- Significance of signal-averaged electrocardiography relation to endomyocardial biopsy and ventricular sion of the tachycardia in these patients, al- stimulation studies in patients with ventricular tachy- cardia without clinically apparent heart disease. JAm Coll though flecainide was similar. Verapamil was Cardiol 1989;14:372-9. not as effective as the other two agents. 7 Holt PM, Wainwright RJ, Curry PVL. Right ventricular response outflow tract tachycardias in patients without apparent Although there is variability of the structural heart disease. Int JCardiol 1986;10:99-1 10. to the test used to assess efficacy of treatment, 8 Deal BJ, Miller SM, Scagliotti D, Prechel D,Gallastegui JL, in a our appears to show that Hariman RJ. Ventricular tachycardia young popula- study proarrhythmic tion without overt heart disease. Circulation 1986; effects may occur in this patient group; some 73:1111-8. 9 Lemery R, Brugada P, Bella PD, Dugernier T, van den Dool patients developed exercise induced VT A, Wellens HJJ. Nonischaemic ventricular tachycardia. whereas these had been free of arrhythmia Clinical course and long-term follow-up in patients with- out clinically overt heart disease. Circulation 1989;79: when drug free; some with non-sustained VT 990-9. when drug free became sustained and haemo- 10 Rowland TW, Schweiger MJ. Repetitive paroxysmal ven- tricular tachycardia with sudden death in a child. Am J dynamically unstable on the drug during Cardiol 1984;53:1729. programmed ventricular stimulation. Patients 11 Benson DW, Benditt DG, Anderson RW, Dunnigan A, will therefore require careful assessment before Pritzker MR, Kudik TJ, Zavorel JH. in young ostensibly healthy patients. Clinical hemodynamic the introduction of long-term drug treatment. and electrophysiologic findings. Am J Cardiol 1983;52: to one in 65-9. Patients who responded drug were, 12 Theine G, Nava A, Corrodo D, Rossi L, Pennelli N. Right general, responsive to the other agents used in ventricular cardiomyopathy and sudden death in young the study. There were, however, some patients people. N Engl JMed 1988;3:129-33. 13 Pietras RJ, Lam W, Bauernfeind R, Sheikh A, Palileo E, http://heart.bmj.com/ in whom one agent was effective whereas there Strasberg B, et al. Chronic recurrent right ventricular tachycardia in patients without ischemic heart disease: was no response to the others. Sotalol was well Clinical, hemodynamic, and angiographic findings. Am tolerated as treatment in the group as a whole Heart J 1983;105:357-66. WL. with few side effects. It therefore seems reason- 14 Brodsky MA, Sato DA, Allen BJ, Chesnie BM, Henry Solitary beta-blocker therapy for life-threatening ven- able to treat such patients with sotalol as first tricular tachyarrhythmias. Chest 1986;89:790-4. 15 Proclemer A, Ciani R, Feruglio GA. Right ventricular line treatment and use other agents only when tachycardia with left bundle branch block and inferior axis this fails. The responsiveness of some of the morphology: clinical and arrhythmological characteristics in 15 patients. PACE 1989;12:977-89. patients in this group to verapamil is interest- 16 Mehta D, Odawara H, Ward DE, McKenna WJ, Davies MJ, on September 27, 2021 by guest. Protected copyright. ing as it suggests that some of these tachy- CammAJ. Echocardiographic and histologic evaluation of the right ventricle in ventricular tachycardias of left cardias may be due to triggered activity rather bundle branch block morphology without overt cardiac than to a re-entry mechanism.2' There are no abnormality. Am J Cardiol 1989;63:939-44. 17 Bruce RA, Hornsten TR. Exercise stress testing in evalua- publications concerned with how efficacy of tion of patients with ischemic heart disease. Prog Car- drugs should be assessed in this group. Our diovasc Dis 1969;11:371-90. 18 Wellens HJJ, Brugada P, Stevenson WG. Programmed data suggest that patients who have therapeutic electrical stimulation of the heart in patients with life- suppression of exercise induced VT, and VT threatening ventricular arrhythmias. What is the sig- nificance of induced arrhythmias and what is the correct induced by programmed stimulation, also have stimulation protocol? Circulation 1985;72:1-7. good control of Holter monitored events and 19 Rahilly GM, Prystowsky EN, Zipes DP, Naccarelli GV, of Jackman WM, Heger JJ. Clinical and electrophysiologic symptoms, suggesting that all three methods findings in patients with repetitive monomorphic ven- monitoring efficacy may play a part in the tricular tachycardia and otherwise normal electrocar- diogram. Am J Cardiol 1982;50:459-68. mangement of such patients. 20 Palileo EV, Ashley WW, Swiryn S, Buernfeind RA, Stras- We conclude that VT associated with a berg B, Petropoulos T, Rosen KM. Exercise provocable right ventricular outflow tract tachycardia. Am Heart J normal heart responds well to all three forms of 1982;104: 185-93. drug treatment used in this study. The most 21 Lerman BB, Belardinelli L, West A, Beme RM, DiMarco JP. -sensitive ventricular tachycardia: evidence efficacious agent for suppression of exercise suggesting cyclic AMP-mediated triggered activity. Cir- induced and VT induced by programmed culation 1986;74:270-80.