[Causes and prognosis of syncope in patients with primary dilated cardiomyopathy]

The causes of adverse prognosis of patients with primary dilated cardiomyopathy remain controversial. Classically, it is thought that syncope is associated with an increased risk of mortality. The aim of this study was to try and identify the causes and prognostic significance of syncope in patients with primary dilated cardiomyopathy. Sixty-five patients aged 31 to 80 with primary dilated cardiomyopathy were admitted for investigation of syncope. The average ejection fraction was 27 +/- 10%. Invasive and non-invasive investigations including complete electrophysiological investigations, were performed. Sustained monomorphic ventricular tachycardia was induced in 14 patients (21.5%), ventricular flutter or fibrillation was induced in 9 patients (14%), a supraventricular arrhythmia in 17 patients (26%), and a conduction defect alone or associated with another arrhythmia in 7 patients (11%). A pathological result of tilt testing was observed in 5 patients (8%). No cause of syncope could be demonstrated in 15 patients (23%). During follow-up (4 +/- 2 years) there was a mortality of 15% which was only correlated with the reduction in left ventricular ejection fraction. The authors conclude that there are many causes of syncope in primary dilated cardiomyopathy: ventricular arrhythmias represent only 35% of cases and do not impact on the prognosis; above all, left ventricular ejection fraction is the most important prognostic factor.

[Does syncope change the results of programmed ventricular stimulation in patients with previous myocardial infarction?]

The induction of a ventricular tachycardia (VT) after myocardial infarction (MI) is associated with a high risk of VT and sudden death (SD) in asymptomatic patients; the purpose of the study was to know if syncope modifies the results of programmed ventricular stimulation (PVS) and the clinical consequences.

METHODS

PVS using two and three extra stimuli delivered in two sites of right ventricle was performed in 1057 patients without spontaneous VT or resuscitated SD at least 1 month after an acute MI; 836 patients (group I) were asymptomatic and were studied for a low ejection fraction or nonsustained VT on Holter monitoring or late potentials; 228 patients (group II) were studied for unexplained syncope. The patients were followed up to 5 years of heart transplantation.

RESULTS

Sustained monomorphic VT (< 280 b/min) was induced in 238 group I patients (28%) and 62 group II patients (29%); ventricular flutter (VT > 270 b/min) or ventricular fibrillation (VF) was induced in 245 group I patients (29%) and 42 group II patients (18%) (P < 0.05); PVS was negative in 353 group I patients (42%) and 124 (55%) group II patients (NS). The patients differ by their prognosis; cardiac mortality was 13% in group I patients and 34% in group II patients with inducible VT < 280 b/min (P < 0.01), 4% in group I patients and 13% in group II patients with inducible VF (P < 0.05), 5% in group I patients and 7% in group II patients with negative study (NS). In conclusion, syncope did not change the results of programmed ventricular stimulation after myocardial infarction. However, syncope increased significantly cardiac mortality of patients with inducible ventricular tachycardia, flutter or fibrillation.

[Risk factors for cardiac mortality in cases of syncope with previous history of myocardial infarction]

Syncope is considered to be a clinical sign predictive of sudden death in patients with a previous history of myocardial infarction. The aim of this study was to determine the prognostic factors in this population. The study population included 228 patients with myocardial infarction over one month old and who had no documented ventricular tachycardia. The patients were referred for investigation of syncope. The left ventricular ejection fraction (LVEF) was measured by echocardiography or radionucleide technique. Complete electrophysiological study including programmed atrial and ventricular stimulation was performed in all cases. The patients were followed up for 6 months to 5 years or until cardiac transplantation (average 3+/-1 years). One hundred and nineteen patients had a LVEF <40% (Group I) and 109 patients had a LVEF >40% (Group II). Sustained monomorphic ventricular tachycardia (VT) with a rate inferior to 280/min was induced in 44 patients in Group I (37%) and in 18 patients in Group II (16.5%), p<0.05. Ventricular flutter or fibrillation was induced in 24 patients in Group I (19%) and in 19 patients in Group II (17%) (NS). Different causes of syncope (conduction disturbances, supraventricular tachycardia, increased vagal tone, severe coronary ischaemia) were found in 23 patients in Group I (19%) and 32 patients in Group II (29%) (NS). Syncope was unexplained in 43 patients in Group I (36%) and 40 patients in Group II (37%) (NS). The prognosis was very different. In Group I, the cardiac mortality was 49% in patients with inducible monomorphic VT <280/min, 35% in those with inducible ventricular flutter or fibrillation but only 9% in patients without inducible ventricular arrhythmias. In Group II, the prognosis was independent of the results of programmed stimulation and much better: cardiac mortality was 5.5% in patients with inducible VT, 5% in those with inducible ventricular flutter or fibrillation and 4% in patients without inducible ventricular arrhyhtmias. The authors conclude that LVEF is the most powerful predictor of cardiac mortality and sudden death in cases of syncope with a past history of myocardial infarction. The prognosis also depends on the results of programmed ventricular stimulation when the LVEF is inferior to 40%. Sustained monomorphic VT is the most frequently induced arrhythmia in this case and the prognosis of these patients is particularly poor. On the other hand, syncope does not appear to be a poor prognostic factor in the group with normal LVEF, even when it is possible to induce VT.

[Syncope in patients with normal EKG and without cardiac disease: value of ambulatory esophageal electrophysiology in determining etiology]

The aim of this study was to determine whether ambulatory oesophageal electrophysiological recordings are valuable in identifying the cause of syncope in patients with a normal ECG and without cardiac disease. One hundred and forty-five patients aged 16 to 88 years of age, without cardiac disease, and with a normal ECG without a documented arrhythmia, were examined for unexplained syncope: 55 patients complained of palpitations at the time of syncope. The electrophysiological study was carried out in the clinic with oesophageal recordings using a classical protocol: Wenckebach point and sinus node recovery time were determined; programmed atrial stimulation was used with delivery of 1 and 2 extra-stimuli on the basal rhythm and with 20/30 micrograms infusion of isoprenaline; blood pressure was monitored. The study was negative in 41 patients (28%). Sinus node dysfunction was observed in 9 patients (6%). A vaso-vagal reaction reproducing the symptoms was induced by isoprenaline in 21 patients (14.5%); a conduction defect was revealed in 2 cases (1%). Atrial fibrillation or tachycardia > 1 minute was induced in 22 patients (15%). Paroxysmal junctional tachycardia was induced in 50 patients (35%). Patients with a negative study were younger than those with sinus node dysfunction or atrial fibrillation (44 +/- 21, 71 +/- 9 and 63 +/- 14 years respectively). Treatment was guided by these results: cardiac pacing, antiarrhythmic therapy or radiofrequency ablation of the reentrant pathway were indicated and suppressed syncope in all but two patients. The authors conclude that electrophysiological studies in the out-patient clinic with oesophageal recordings is a safe, rapid and economic method of detecting arrhythmias (sinus node dysfunction or supraventricular tachycardia) in 60% of patients with syncope, especially if they have symptoms of palpitations.

Value of non-invasive and invasive studies in patients with bundle branch block, syncope and history of myocardial infarction

The prognosis of patients with bundle branch block (BBB) and myocardial infarction (MI) is poor, particularly for patients suffering from syncope. The purpose of this study was to investigate the diagnostic value of some techniques for the evaluation of the mechanism of syncope in patients with MI and BBB and their prognosis.

METHODS

We prospectively obtained the results of clinical history, 24 h Holter monitoring, left ventricular ejection fraction (LVEF), signal-averaged ECG (SAECG) and programmed ventricular stimulation in 130 patients with syncope, MI and BBB. 81 of them had right (R)BBB and 49-left (L)BBB.

RESULTS

Ventricular tachycardia (VT) was identified as the main cause of syncope in patients with MI and BBB: 68% of them had inducible VT. The sensitivity (se) and specificity (sp) of non sustained VT on Holter monitoring for the detection of VT were respectively 42.5 and 47% in patients with RBBB, 62 and 36% in those with LBBB; se and sp of LVEF <40% were 67.5% and 65% in patients with RBBB, 85 and 9% in those with LBBB; se and sp of the combination of 2 of the 3 SAECG criteria, QRS duration > 155 ms, LAS duration >30 ms and RMS 40 < 17 microV were respectively 50 and 57% in patients with RBBB; se and sp of the combination of 2 of the 3 criteria QRS duration >165 ms, LAS duration >40 ms and RMS 40 <17 microV were 73 and 55.5%) in patients with LBBB. During the follow-up (4.7 years +/- 2.5), 12 patients died suddenly and 12 patients died from heart failure. Univariate and multivariate analysis revealed than only the induction of VT was a significant predictor of sudden death. A long QRS duration (> 165 ms) and induction of VT were independent predictors of total cardiac mortality.

CONCLUSION

Among noninvasive studies, only the determination of filtered QRS duration was a significant predictor of cardiac mortality in the case of a prolongation (> 165 ms). Sudden death was only predicted by the induction of sustained VT. Because of the high incidence of inducible sustained VT, the low value of Holter monitoring and decreased LVEF for the prediction of ventricular arrhythmias and the poor prognosis of patients with inducible VT and low LVEF, systematic programmed ventricular stimulation is indicated in patients with MI, syncope and BBB, whatever the non-invasive studies results.

[Can the supraventricular proarrhythmic effects of class 1C antiarrhythmic drugs be prevented with the association of beta blockers?]

Due to their electrophysiological characteristics, class 1 antiarrhythmic drugs can induce an auricular flutter with a 1/1 response. In addition to antiarrhythmic treatment, several authors have therefore considered using drugs capable of slowing auriculoventricular nodal conduction and preventing the 1/1 response. Beta-blockers have been proposed as candidate drugs. In this study, two patients were treated with an association of class 1 antiarrhythmic drugs (cibenzoline in one case, flecainide in the other) and beta-blockers. The administration of these drugs resulted in an atrial proarrhythmic response, and wide QRS tachycardia. Although both subjects had underlying heart disease, the tachycardia was relatively well tolerated in both instances. It was concluded that although beta-blockers may not suppress the risk of atrial proarrhythmia, they at least permit an improved tolerance to this complication.

[Prolongation of the averaged QRS complex. A simple prognostic factor in patients with post-infarction bundle branch block and a history of syncope]

Patients with a history of myocardial infarction and complete bundle branch block with syncopal episodes have a high risk of sudden death: the identification of the cause of the syncope is therefore essential. The aim of the study was to assess the diagnostic value of non-invasive techniques used in the investigations of syncope: 24 hour Holter recording, high amplification ECG and measurement of left ventricular ejection fraction. The results of these investigations were compared with those of complete electrophysiological investigation evaluating atrioventricular conduction and the inducibility of tachycardia. The patient population was 134 patients, 83 with right bundle branch block and 51 with left bundle branch block. Ninety one patients had inducible sustained ventricular tachycardia and 24 had atrioventricular conduction defects: of these, 14 also had ventricular tachycardia. During follow-up, there were 12 sudden deaths and 13 deaths from cardiac failure. Uni- and multivariate analysis showed induction of ventricular tachycardia to be a significant risk factor for global mortality and sudden death but prolongation of the averaged QRS complex (> 165 msec) was also an independent risk factor of global cardiac mortality. The authors conclude that simple prolongation of the averaged QRS duration > 160 ms in patients with right bundle branch block and > 170 ms in patients with left bundle branch block after myocardial infarction and syncope is a significant poor prognostic factor. However, this sign is not predictive of sudden death.

[Effect of golf on sinus rate variability]

There are no or very few studies in the literature on the effects of golf on heart rate and its parameters. The purpose of the study was to evaluate the effects of a precision sport, golf, on heart rate variability (HRV). The study population consisted of six high-level golfers aged 25 to 40 years, without cardiac disease. HRV was studied three hours before a golf competition, during the four hours of the competition and three hours after the match was over. The following parameters of HRV were calculated during 12 games of golf: mean heart rate (HR), standard deviation of the mean RR intervals (SDNN), root mean square of successive differences in RR intervals among consecutive normal beats (rMSSD), percent differences between normal RR intervals that are greater than 50 ms computed over the entire 24-hour recording (pNN50), low-frequency amplitude (LF), high-frequency amplitude (HF) and LF/HF ratio: ratio of low-to-high frequency power. Analysis of the results indicates significant variations of all parameters which occur just at the beginning of the game, persist throughout the match and remain three hours after its completion: heart rate is increased; total HRV is decreased but parameters reflect parasympathetic activity; pNN50, rMSSD and 1-117 are principally decreased. In conclusion, golf significantly affects HRV just at the beginning of golf competition, probably because of stress. These changes progressively decrease but they are still significant three hours after the end of the competition.

Role of the etiology of cardiomyopathies on exercise capacity and oxygen consumption in patients with severe congestive heart failure

Peak oxygen consumption is of great importance for the decision of heart transplantation in congestive heart failure. Moreover, the level of exercise capacity seems to depend on the etiology of congestive heart failure. This study compared 14 heart failure patients with idiopathic dilated cardiomyopathy (group 1) to 14 heart failure patients with cardiomyopathy due to ischemic heart disease (group 2), matched for sex (13 male, one female in each group), age +/-10 years, left ventricular ejection fraction +/-5% and pulmonary artery mean pressure +/-5 mm Hg, to assess exercise capacity and oxygen consumption independently of the age, sex and the level of left ventricular dysfunction. Right ventricular function was also assessed. No difference existed in terms of right ventricular parameters. Maximal exercise parameters were significantly higher in group 1 than in group 2. Peak oxygen consumption was statistically higher in group 1 than in group 2. In the whole population, a significant correlation was found between peak oxygen consumption and right ventricular ejection fraction (r=0. 44, P<0.02) but not between peak oxygen consumption and left ventricular ejection fraction. For similar levels of left ventricular dysfunction, exercise capacity and oxygen consumption appear to be better in idiopathic dilated cardiomyopathy than in ischemic cardiomyopathy, thereby suggesting that functional tolerance of left ventricular dysfunction might depend on the etiology of severe congestive heart failure.

[Prognostic value of serial electrophysiological tests in inducible sustained ventricular tachyarrhythmias]

The authors report the results of a study evaluating serial electrophysiological tests on a series of 166 patients with inducible sustained ventricular tachyarrhythmia. The initial electrophysiological investigation was indicated because of sustained ventricular arrhythmias documented in 95 patients or suspected in 71 symptomatic patients. Serial tests allowed identification of a protective antiarrhythmic treatment (non-inducible ventricular tachycardia) in 74 responding patients (44.6%) (group R) after 1.3 +/- 0.5 therapeutic trials versus 1.8 +/- 0.8 inconclusive trials in 92 non responding patients (group NR). Multivariate analysis demonstrated the absence of any underlying ischaemic heart disease (p < 0.01) and the presence of spontaneous ventricular fibrillation (p < 0.01) as independent predictive factors of success during serial testing. A follow-up of 43 +/- 29 months was available for 151 patients (91%). kaplan-Meier survival curves showed a better long-term prognosis for group R with survival rates of 97%, 87% and 70% at 1.3 and 6 years, respectively, versus 83%, 68% and 45% for group NR. Two variables were considered on multivariate analysis to be predictive factors of survival: left ventricular ejection fraction (p < 0.001) and response to serial electrophysiological tests (p < 0.02). Therapeutic ventricular pacing therefore remains a reliable method to select patients whose prognosis is improved with antiarrhythmic treatment after induction of sustained ventricular arrhythmia.

Prognostic significance of angina pectoris > or = 30 days before acute myocardial infarction in patients > or = 75 years of age

We compared the prognostic significance of prior angina pectoris in 151 patients > or = 75 years of age admitted for acute myocardial infarction. There was a similar in-hospital course, but the long-term outcome was poorer in patients with prior angina.

[Myocardial infarction in patients over 75 years of age. Hospital characteristics and long-term follow-up]

OBJECTIVES

Analyze management of myocardial infarction in elderly subjects and assess long-term outcome.

METHODS

We studied retrospectively a series of 151 consecutive cases of acute myocardial infarction in patients over 75 years of age and compared then with a group of young subjects under 65 years of age admitted for the same pathology during the same period (1989-1993).

RESULTS

In the elderly population, female sex, past history of angina or infarction, atypical presentation and hemodynamic complications were more frequent in the elderly population (left ventricle failure 44 vs 13%, cardiogenic shock 17.2 vs 0.7% without any difference in localization. Mortality was higher in the elderly group (23.2 vs 2.6%) with 68.6% of the deaths due to primary cardiogenic shock. Beta-blockers were used less frequently in the elderly population (31.8 vs 83.0%) as was thrombolysis (26.5 vs 64.5%); coronography was performed less often (21.8 vs 92.7%) as was percutaneous revascularization (9.9 vs 36.4%) or surgery (1.3 vs 6.6%). Survival at 1, 2 and 5 years was 88, 76 and 57% in the elderly group (Kaplan-Meier plot). A past history of unstable angina and a critical episode of left ventricle failure were factors predicting overmortality.

CONCLUSION

Acute myocardial infarction remains a severe condition in patients over 75 years of age with overmortality during hospitalization and poor long-term prognosis. Clinical signs of poor prognosis could help guide selection for more aggressive therapeutic management during the post-infarction period, notably in terms of coronary revascularization.

[Syncopes associated with mitral valve prolapse. Mechanisms]

Prolapsed mitral valve prolapse (PMV) is classically associated with disorders of ventricular excitability whose significance is unclear. However, syncope can suggest the possibility of a serious ventricular arrhythmia. The objective of this study was to try to identify the mechanisms of dizziness and syncope associated with PMV. We report the results of programmed atrial and ventricular stimulation performed under baseline conditions and after administration of Isuprel in 56 patients with PMV: 27 patients had a history of presyncope or syncope (group I), 14 had spontaneous atrial or supraventricular tachycardias without dizziness or syncope (group II) and 15 were asymptomatic and investigated for VEBs or conduction disorders (group III). The following results were obtained: In group I, 6 patients experienced sustained inducible ventricular tachycardia (VT); an atrial tachycardia (atrial tachycardia and/or atrial fibrillation) (AT) was also induced in 5 of them. In another 19 patients, a supraventricular tachycardia (SVT) and/or AT was induced. A total of 24 atrial or junctional tachycardias were triggered in this group. In group II, AT and/or SVT were reproduced in 13 out of 14 cases (93%). In group III, AT was triggered in 3 patients (20%). SVT were induced by Isuprel while AT were triggered prior to administration of Isuprel, under baseline conditions, and 3 of them were reproduced during vagal manoeuvres. A ventricular arrhythmogenic effect was observed in two cases in group II while taking class I antiarrhythmics. In conclusion, spontaneous AT and SVT of PMV are easily inducible with a sensitivity of 93%, but are difficult to induce in asymptomatic subjects. The high incidence of TA and SVT in the case of unexplained presyncope in subjects without documented tachycardia therefore appears to be suggestive of a relationship between these presyncopes and AT or SVT. However, the search for VT should take precedence. SVT appear to be catecholaminergic while AT tend to be vagal.

Significance and prevalence of inducible atrial tachyarrhythmias in patients undergoing electrophysiologic study for presyncope or syncope

The purpose of the study was to report the prevalence of inducible supraventricular tachyarrhythmias (SVTA) in 827 consecutive patients aged 17 to 90 years who did not have spontaneous documented SVTA and who had unexplained presyncope and/or syncope. The electrophysiologic study (EPS) included programmed atrial and ventricular stimulation up to two extrastimuli at three cycle lengths, and the study of sino-atrial and AV conduction. The results were as follows. EPS was normal in 386 patients. Inducible junctional tachycardia or atrial flutter and fibrillation was the only finding in 187 patients (23%). In the remaining patients we found ventricular tachycardia in 103 (12%), heart block in 67 (8%), sick sinus syndrome in 56 (7%) and increased vagal tone in 28 (3%). The presence of an underlying heart disease (47%) and salvos of atrial premature beats on Holter monitoring (39%) were significantly correlated with the induction of SVTA. However, the comparison with similar groups without syncope indicates that only the induction of SVTA in patients with hypertrophic cardiomyopathy and mitral valve prolapse was significantly correlated with the history of syncope. In patients without heart disease or with prior myocardial infarction or decreased left ventricular function, the induction of SVTA, which is not associated with hypotension in the supine position, could require an induction after head-up tilting, because of the lack of specificity of programmed stimulation in these patients. Programmed atrial stimulation should be systematically performed in patients with unexplained syncope, in particular in those with hypertropic cardiomyopathy and mitral valve prolapse, who require a specific treatment, if a SVTA is induced. In other patients the results of programmed atrial stimulation should be interpreted cautiously.

Isolated myocardial bridges with angiographic milking of the left anterior descending coronary artery: a long-term follow-up study

Among 7467 consecutive coronary angiograms performed during an 8-year period, 61 patients had a myocardial bridge of the left anterior descending coronary artery. The overall prevalence of myocardial bridges was 0.82% (from 0.41% to 1.16% per year). Among these patients, 26 had coronary artery disease, 4 had valvular heart disease, and 3 had cardiomyopathy. We studied the long-term outcome (11 +/- 3 years) of the other 28 patients with isolated milking at baseline. Two groups were constituted according to the percentage of systolic reduction of the left anterior descending coronary artery lumen: group A, < 50% (15 patients) and group B, > or = 50% (13 patients). During follow-up, 1 group A patient (cancer) and 2 group B patients (1 cancer and 1 suicide) died. Moreover, 1 group B patient was lost to follow-up. None of the patients sustained a myocardial infarction during follow-up. In group A patients, 71% felt very well or well and 50% had clinical symptoms; 64% took antianginal medications. In group B patients, 50% felt well and 70% had clinical symptoms; 50% took antianginal drugs. The long-term prognosis of isolated myocardial bridges of the left anterior descending coronary artery is good and is independent of the severity of systolic narrowing of internal lumen diameter.

[Should a signal-averaged electrocardiogram be requested in the evaluation of malaise and syncope?]

In order to determine whether signal-averaged electrocardiography was useful in the diagnosis of syncopal ventricular tachycardia, 244 subjects with malaise or unexplained syncope without documented ventricular tachycardia underwent endocavitary electrophysiological study and signal-averaged electrocardiography with a 25 Hz bandpass filter. Ninety-three patients had no apparent cardiac disease whereas 151 patients had cardiac problems. ventricular tachycardia was induced in 91 patients. Fifty-two of them (57%) had ventricular late potentials. Twenty-two patients without inducible ventricular tachycardia also had late potentials (14%). The diagnostic value of signal-averaged electrocardiography depended on the cardiac disease: in the absence of cardiac disease, its sensitivity was poor (31%) but the specificity was excellent (96%). In the presence of cardiac disease, the sensitivity improved (63%) but the specificity was not as good (67%). The lack of sensitivity in the group with cardiac disease generally concerned subjects with inducible rapid ventricular tachycardia. The authors conclude that signal-averaged electrocardiography should not be requested in the investigation of unexplained syncope in subjects without cardiac disease to demonstrate abnormal ventricular excitability which is very rate in these subjects. On the other hand it is more valuable in those with underlying cardiac disease although inducible rapid ventricular tachycardia may still escape detection.

Programmed ventricular stimulation in survivors of acute myocardial infarction: long-term follow-up

The prognostic significance of ventricular tachyarrhythmias induced by programmed ventricular stimulation was evaluated in 492 consecutive survivors of acute myocardial infarction (AMI). Holter monitoring, signal-averaged electrocardiogram (ECG) and measurement of left ventricular ejection fraction (EF) were also performed. The protocol used up to 3 extrastimuli. Sustained monomorphic ventricular tachycardia (VT) < 270 beats/min, > 270 beats/min (ventricular flutter) (VFI), and ventricular fibrillation (VF) were induced in 99, 66 and 52 patients, respectively. Long term follow-up (mean 3.7 +/- 2.2 years) showed that most episodes of VT occurred during the first months following AMI (n = 14), but some patients (n = 6) could develop VT as late as 4 years after AMI. Sudden death (SD) (n = 22) always occurred during the first year following AMI. Multivariate analysis demonstrated that EF < 30% and induction of a VT < 270 beats/min were the only predictors for total cardiac death (P < 0.001). EF < 30%, induction of a VT < 270 beats/min and also of VFI (P < 0.05) were predictors for VT and SD: the risk was 4% in patients without inducible VT, 12% in those with inducible VF1, and 21% in those with inducible VT < 270 beats/min. In conclusion, induction of a sustained monomorphic VT < 270 beats/min or > 270 beats/min is a predictor of arrhythmic events during the first year as well as 4 years after myocardial infarction. However the risk of arrhythmic sudden death decreases after the first year, while the risk of VT persists. Because of the low positive predictive value of programmed stimulation (respectively 21% and 12% for the induction of a sustained VT and VFI), we recommended the indication of programmed stimulation in only the patients with one abnormal non-invasive investigation.

[Changes in heart rate after ventricular stimulation; correlations with vagal tone]

The authors report a new method of studying the autonomic nervous system, especially vagal tone, during endocavitary electrophysiological studies. After termination of fixed ventricular pacing at incremental rates to 200/min, an initial acceleration of the heart rate is observed followed about 5 seconds later by a sudden slowing. This phenomenon was studied in 278 patients. Ninety seven patients had no cardiac disease: the variation in heart rate was 33 +/- 18%. In the 181 other patients with cardiac disease (ejection fraction 35 +/- 16%) the variation was only 21 +/- 16% (p < 0.01). When the ejection fraction was less than 30%, the variation was only 13 +/- 4%. When the heart rate variation was less than 10%, the prognosis was poor because, of the 48 patients with this sign, 13 died, whereas there were only 2 deaths in the 133 other patients with cardiac disease and preserved adaptation. In 14 patients without cardiac disease the injection of 2 mg of atropine suppressed all adaptation of the heart rate, whilst in 18 other patients, oral betablockers reduced the variation but it persisted to a significant degree. The authors conclude that the adaptation of the heart rate after rapid ventricular stimulation is probably a reflection of vagal tone and may be used to assess the prognosis of subjects undergoing electrophysiological investigations.

[Epidemiology of bacterial endocarditis in France in 1991]

In order to update our information about the incidence and demographic, microbiological and clinical characteristics of infective endocarditis (IE) in France, a 12 month long study was carried out in three regions: Ile de France, Rhône-Alpes and Lorraine. Four hundred and fifteen cases of IE were recensed: certain (32%), probable (53%) or possible (15%). The annual incidence was 24.3 per million. The average age was 56 +/- 19 years. There was no past history of cardiac disease in 34% of cases; 33% had native valvular heart disease and 22% had one or more valvular prostheses. The site of IE was mitral in 39%, aortic in 36%, tricuspid in 6% and other or multivalvular in 19% of cases. The causal microorganism was isolated in 92% of cases. It was a streptococcus in 58% of cases (S. viridans in 27%; group D streptococcus + enterococcus in 23%); a staphylococcus was isolated in 23% of cases (Staphylococcus Aureus in 18%) and another microorganism in 11% of cases. The presumed portal of entry was dental in 24%, gastro-intestinal in 13%, cutaneous in 6% and urinary in 4% of cases. Twenty patients were intravenous drug addicts. Forty-five patients had medical or surgical procedure. Twenty-four per cent of patients were operated during the first two months, 17% died during this period (15% of operated and 18% of non-operated patients). Despite the advances in antibiotic therapy and in cardiac surgical techniques, IE seems to be as common and as severe as ten years ago.(ABSTRACT TRUNCATED AT 250 WORDS)

[Results of systematic programmed ventricular stimulation after myocardial infarction. Which protocol should be recommended?]

The authors report the prognostic value of ventricular arrhythmias induced by routine programmed ventricular stimulation after the acute phase of myocardial infarction. The protocol consisted of two extrastimuli in the first 185 patients and 3 extrastimuli in 308 patients. The use of 3 extrastimuli increased the incidence of inducible sustained monomorphic ventricular tachycardia (VT) < 270/mn, from 17 to 22% and, more importantly, that of ventricular fibrillation from 4 to 17%. Induction of ventricular flutter (monomorphic VT > 270/mn) was not increased. A long follow-up period (average 4 +/- 2 years) showed that the risk of VT was increased during the first months after infarction (n = 14), and that, 4 years later, other patients develop VT (n = 6). The risk of serious arrhythmias (VT and sudden death) was significantly higher in patients with inducible VT < 270/mn (20%) than in patients without inducible VT, but it was also higher in patients with inducible ventricular flutter (12.5%). The use of a third extrastimulus has a low positive predictive value for arrhythmic events (10%). This study confirms that the induction of sustained monomorphic VT after myocardial infarction is associated with an increased risk of arrhythmic events but the positive predictive value is relatively low (17%). In view of the risk of inducing non-specific ventricular fibrillation, the authors recommended using a stimulation protocol with only 2 ventricular extrastimuli.

[Cardiac arrest reversed: causes and treatments]

The aim of this study was to report the probable mechanism of resuscitated cardiac arrest without acute myocardial infarction. Fifty-seven cases were recensed but the arrest was only documented in 44 subjects. Systematic non-invasive investigations and programmed stimulation showed that the diagnosis of cardiac arrest was probably false in 5 patients and, in the others, that a ventricular arrhythmia was probably the cause (63%). The occurrence of cardiac arrest under antiarrhythmic therapy may reveal an underlying abnormality requiring specific therapy (3/8). The absence of cardiac disease did not exclude the risk of VF (3 cases). When reproducible, ventricular arrhythmias were present during programmed stimulation, the prognosis was good if the arrhythmia could not be induced under antiarrhythmic therapy. It was easier to find an effective treatment for inducible ventricular fibrillation-flutter (13/17) than for inducible ventricular tachycardia (7/17). The prognosis was poor if the arrhythmia was unchanged during programmed stimulation under antiarrhythmic therapy and non-pharmacological treatment was required.

[Results of high amplification electrocardiogram in primary dilated cardiomyopathy]

Idiopathic dilated cardiomyopathy carries a high risk of sudden death. It is also associated with sustained ventricular tachycardia. A complex ventricular arrhythmia is recorded in 3/4 of cases on Holter monitoring which has a low specificity. The aim of the study was to determine whether signal-averaged electrocardiography could provide a better evaluation of the prognosis of this condition. The results of signal-averaged electrocardiography were compared with those of 24 hour Holter monitoring and of systematic programmed ventricular stimulation in 58 patients with idiopathic dilated cardiomyopathy. Late ventricular potentials were recorded in 13 of the 14 subjects with inducible and usually spontaneous sustained ventricular tachycardia. The sensitivity of the technique for evaluating the risk of sustained VT was therefore good (93%). Late potentials were also recorded in 9 patients with induced ventricular flutter or fibrillation, these patients being symptomatic (dizzy spells). Late potentials were also demonstrated in 14 of the 35 asymptomatic patients without inducible VT, indicating that this non-invasive investigation had a limited specificity (60%). In addition, during follow-up of the patients, the risk of sudden death was difficult to demonstrate. Late potentials were only found in subjects with inducible sustained VT but no in the other cases. In conclusion, signal-averaged electrocardiography seems to be valuable for evaluating the risk of sustained VT in subjects with idiopathic dilated cardiomyopathy and complex ventricular arrhythmias. The detection of the risk of sudden death is probably impossible by this technique.

[Incidence of inducible supraventricular tachycardia in dysplasia of the right ventricle]

Arrhythmogenic right ventricular dysplasia (ARVD) is classically associated with ventricular tachycardia and the prevalence of supraventricular tachycardia in this condition is not well known. The aim of this study was to observe the response of 20 patients with ARVD to programmed atrial stimulation and compare it with 150 subjects without cardiac disease or spontaneous supraventricular tachycardia. The protocol used 2 atrial extra-stimuli delivered on 3 paced cycles. Programmed atrial stimulation with 1 extrastimulus was repeated after infusion of 20 to 30 micrograms of Isoproterenol. Sustained supraventricular tachycardia could be induced in 13 patients with ARVD (65%) and 17 control subjects (11%) (p < 0.001). It was not possible to distinguish patients with inducible supraventricular tachycardia from those without inducible arrhythmias by electrophysiologic parameters. Isoproterenol facilitated the induction of VT but not supraventricular tachycardia. Three patients with inducible supraventricular tachycardia developed spontaneous atrial fibrillation. In conclusion, there is a relatively high incidence of inducible supraventricular tachycardia in ARVD: Isoproterenol does not facilitate this tachycardia, contrary to ventricular tachycardia.

Clinical significance of rapid ventricular tachycardia (> 270 beats per minute) provoked at programmed stimulation in patients without confirmed rapid ventricular arrhythmias

Rapid uniform ventricular tachycardia (VT) (> 270 beats/min) or ventricular flutter induced during electrophysiological studies is thought not to be clinically significant in patients without cardiac arrest or documented rapid VT. The purpose of the study was to follow up 73 patients with inducible ventricular flutter but without confirmed rapid spontaneous VT. A long follow up (mean 3.5 years) identified two groups of patients. The first group had an excellent outcome and was characterised by a normal 24 hour Holter monitoring. In the second group, however, the risk of cardiac mortality was high (35%) and spontaneous VT was < 270 beats/min (26%) and was characterised by couplets or salvos of extrasystoles on Holter monitoring. In this group the history of syncope and decreased left ejection fraction increased the risk of mortality and VT. The presence of late potentials increased the risk of spontaneous VT. Electrophysiologically guided antiarrhythmic therapy reduced the risk of VT. Ventricular flutter was a non-specific finding in patients with normal Holter monitoring. In contrast, in patients with salvos of extrasystoles, ventricular flutter was associated with a high risk of cardiac mortality and VT.

[Successive decrease of left ventricular segmental kinetic disorders after transluminal coronary angioplasties in the same patient]

The authors report the case of a patient developing two successive left ventricular kinetic abnormalities secondary to acute or chronic ischemia, and reversible after transluminal coronary angioplasty. The concept of myocardial hibernation is suggested as a possible mechanism.

[Programmed ventricular stimulation in unexplained syncope: risk factors for induction of ventricular tachycardia]

The aim of this study was to identify the factors associated with the induction of ventricular tachycardia (TV) by programmed ventricular stimulation in patients with unexplained syncope. Sustained VT was induced in 71 out of 619 patients (11.5%) with syncope. A comparison of subjects with inducible VT and those without inducible VT showed underlying cardiac disease to be more common (89% versus 16%), more Holter abnormalities (Grade IVa ventricular extrasystoles) (60.5% versus 10%) in the first group but that signal-averaged ECG, recorded in 51 cases, was not sufficiently specific to differentiate the two groups (delayed potentials in 57% versus 43%). When syncope occurred in a subject without apparent cardiac disease with a normal Holter recording, inducible VT was rare (1%). On the other hand, when syncope was associated with cardiac disease and/or an abnormal Holter recording, VT could be induced in 45 to 64% of cases. In addition, as inducible VT was associated with severe infrahisian conduction defects in 3 cases, the following strategy is suggested in patients with unexplained syncope: programmed ventricular stimulation should be performed systematically during endocavitary electrophysiological investigation of AV conduction in patients with cardiac disease and if the non-invasive investigations, Holter monitoring or echocardiography, are abnormal.

[Results of programmed ventricular stimulation in induced non-sustained polymorphic ventricular tachycardia and maintenance of stimulation]

Programmed ventricular stimulation risks inducing non-pathological ventricular fibrillo-flutter. The aim of this study was to determine if the induction of a non-sustained polymorphic ventricular tachycardia (over 5 intraventricular reentries) could prevent this incident. One hundred and thirty-three non-sustained polymorphic tachycardias were induced by 2 or 3 extrastimuli during 1450 programmed ventricular stimulation studies. Ventricular stimulation was continued and led to ventricular fibrillo-flutter in 46 cases (Group I); to induction of sustained ventricular tachycardia in 26 cases (Group II) or to no other arrhythmias excepting the non-sustained tachycardia in 61 cases (Group III). The duration of the salvo was similar in all 3 groups. The rate of the induced arrhythmia was significantly lower in Group II (234 vs 290/min). The essential difference between the three groups was the clinical context. Only patients in Group II had previously documented sustained ventricular tachycardia and only patients in Group III had no apparent underlying cardiac disease. These results suggest that the decision to stop programmed ventricular stimulation should be based on the clinical indications of the study. In patients with previously documented or probable sustained ventricular tachycardia, it would seem to be necessary to continue ventricular stimulation irrespective to the rate and duration of the induced non-sustained ventricular tachycardia.

Proximal rupture and intracoronary entrapment of a rotating device during low-speed rotational coronary angioplasty

While attempting to recanalize a right coronary artery obstruction by using a low-speed rotating catheter (Rotacs), proximal rupture of the catheter body occurred with entrapment of the blunt tip in the obstruction. To retrieve the device, it was necessary to severe the guiding catheter and the flexible tube of the Rotacs. At low-speed rotation the flexible segment of the catheter was then pulled back.

[Relations of the duration of pre-existing angina pectoris, collateral circulation and left ventricular function after isolated coronary occlusion with or without myocardial infarction]

The aim of this retrospective study was to determine the relationship between the duration of preceding angina pectoris, collateral circulation and left ventricular function after isolated coronary occlusion with or without myocardial infarction. Coronary angiography of 138 consecutive patients showed isolated and complete occlusions of the left anterior descending (58 patients) or right coronary artery (80 patients). One hundred and four patients had myocardial infarction with (Group A, n = 21) or without (Group B, n = 83) preceding angina pectoris and 34 had angina without myocardial infarction (Group C). The left ventricular ejection fraction was measured by ventriculography in the 30 degrees right anterior oblique projection. The collateral circulation was assessed by coronary angiography and evaluated as follows: no flow or flow limited to collateral branches (subgroup 1) and partial or complete filling of the epicardial arterial segment (subgroup 2). In the global population the left ventricular ejection fraction was higher and the duration of preceding angina pectoris was longer in the subgroups with a well developed collateral circulation. There was no difference in ejection fraction between Groups A and B (presence of myocardial infarction), on the other hand, within each of the groups, a good collateral circulation (subgroup 2) was associated with a significantly higher ejection fraction. Group C (without infarction) patients had better ejection fractions than Groups A or B, especially when the collateral circulation was poorly developed. Within Group C, the quality of the collateral circulation did not seem to affect the ejection fraction. The left ventricular ejection fraction is lower in patients with isolated coronary occlusion and myocardial infarction.(ABSTRACT TRUNCATED AT 250 WORDS)

[Induction of supraventricular tachycardia (paroxysmal junctional tachycardia and atrial tachycardia) by esophageal stimulation]

Transesophageal stimulation is tending to replace endocavitary electrophysiological studies in the investigation and treatment of supraventricular tachyarrhythmias. The aim of this study was to determine the sensitivity of this technique in the evaluation of paroxysmal junctional tachycardia (PJT) and atrial tachycardia (AT). Fifty-eight patients with these arrhythmias (PJT, n = 23; AT, n = 35) were investigated under basal conditions and then during Isoproterenol infusions with a protocol using incremental atrial stimulation and programmed atrial stimulation delivering one and two extra-stimuli on two paced rhythms (400-600 ms). It was possible to induce the arrhythmia in the 23 patients with PJT either under basal conditions (n = 16) or during Isoproterenol (n = 7). A reentrant mechanism was suggested in 22 patients by the following findings: position of the auriculogramme with respect to the ventriculogramme, presence or absence of a delaying branch block, situation and morphology of the P wave in lead V1 compared with atrial activation recorded by the esophageal catheter. Atrial tachycardia was induced in 26 patients (74 per cent), 19 under basal conditions, 6 with Isoproterenol and once after carotid sinus massage. As a conclusion, we can say that the sensitivity of transesophageal stimulation is the same as for endocavitary stimulation.

[Effect of complete bundle-branch block on the averaged signal of high amplification electrocardiogram]

Intraventricular conduction defects delay ventricular activation and change the appearances of the signal averaged electrocardiogram. The aim of this study was to determine criteria capable of identifying patients with bundle branch block at high risk of ventricular tachycardia (VT). Two hundred and twenty four patients were studied by Simson's method. One hundred and twenty eight patients (Group I control) had narrow QRS complexes and sequellae of previous myocardial infarction. Eighty four patients had no clinical or inducible VT; 44 had clinical and/or inducible VT with programmed stimulation. Forty six patients (Group II) had complete right bundle branch block (RBBB); 30 had no VT and 16 had VT. Twenty seven patients (Group III) had complete left bundle branch block of whom 18 had no VT and 9 had VT. Twenty three patients (Group IV) had RBBB with operated tetralogy of Fallot; 16 had no VT and 7 had VT. In the control group, the results of signal averaged ECG were the same as those reported in the literature: prolongation of the duration of the averaged QRS (136 +/- 35 ms vs 104 +/- 14 ms), decrease in amplitude of the last 40 ms (11 +/- 15 microV vs 43 +/- 28 microV) and an increase in the duration of less than 40 microV terminal activity (53 +/- 30 ms vs 28 +/- 11 ms) in those subjects with VT compared to those without VT. In Groups II, III and IV no significant difference was found in the amplitude of the last 40 ms or duration of less than 40 microV activity between patients with and without VT.(ABSTRACT TRUNCATED AT 250 WORDS)

Role of previous angina pectoris and collateral flow to preserve left ventricular function in the presence or absence of myocardial infarction in isolated total occlusion of the left anterior descending coronary artery

The aim of this study was to determine whether previous angina pectoris and collateral circulation influenced myocardial function after isolated coronary occlusion. In 58 consecutive patients, coronary angiography showed a complete isolated occlusion of the left anterior descending coronary artery; 43 patients (74%) had previous myocardial infarction. Duration of previous angina pectoris was defined as the time from the first ischemic symptom to the date of myocardial infarction or of coronary angiography in the absence of myocardial infarction. Left ventricular ejection fraction was measured on the 30 degrees right anterior oblique projection of the left ventricular angiogram. Collateral circulation was graded as follows: none or filling limited to side branches (group 1) and partial or complete filling of the epicardial arterial segment (group 2). Group 2 (40 patients) had higher ejection fraction (57 vs 38%; p less than 0.0001) and longer duration of previous angina pectoris (11 vs 0.1 months; p less than 0.002) than group 1 (18 patients). A longer duration of previous angina pectoris probably allows collateral development before coronary occlusion in 1-vessel coronary artery disease, thereby limiting myocardial damage.

[Frequency of the onset of supraventricular tachyarrhythmias as a function of underlying heart disease]

The prevalence of inducible ventricular arrhythmias is related to the underlying pathology. This study was undertaken to determine the prevalence of supraventricular tachyarrhythmias (SVT), atrial tachycardia, flutter or fibrillation, sustained for over 30 seconds. Programmed atrial stimulation was used to deliver 1 or 2 extrastimuli during sinus and paced rhythm in 230 subjects without obvious cardiac disease (149 without and 81 with spontaneous SVT) and 432 patients with documented cardiac pathology (407 without and 25 with spontaneous SVT). The incidence of inducible SVT with respect to that of spontaneous SVT and in relation to cardiac pathology was as follows: (table; see text) The prevalence of inducible SVT in patients without spontaneous SVT was related to the type of pathology: (table; see text) These results show that in patients with spontaneous SVT the induction of the arrhythmia was facilitated by the presence of underlying cardiac pathology (sensitivity increasing from 67% to 88%). In patients without spontaneous SVT, the nature of the underlying disease was related to the prevalence of inducible SVT, the risk being major in SA block, right ventricular dysplasia and mitral valve prolapse (60-80%) and moderate in dilated CMP and myocardial infarction (35 to 40%).

[Difficulties in the echocardiographic diagnosis of false aneurysm of the left ventricle. Apropos of 2 cases]

The echocardiographic diagnostic criteria of left ventricular pseudo-aneurysm are well established: the demonstration of a narrow-necked communication between the left ventricular cavity and the aneurysm and endocardial discontinuity at the site of myocardial rupture. The authors report two cases in which these criteria were fulfilled, leading to an echocardiographic diagnosis of pseudo-aneurysm which was erroneous as the operative findings were those of true left ventricular aneurysms.