[Brazilian multicenter study of sotalol effectiveness in ventricular arrhythmias]. / Estudo multicêntrico Brasileiro da eficácia do sotalol em arritmias ventriculares.

PURPOSE: To evaluate the effects of sotalol in patients with nonsustained ventricular tachyarrhythmia (NSVT). METHODS: Ninety patients were enrolled. Patients were submitted to a double-blind crossover randomized study (placebo x 320 ms/po/d/sotalol; 4 weeks, after a wash-out control period. Holter recordings were performed in control (Ct), placebo (Pb) and drug (Dg) periods. Eligible patients had > 50/h isolated ventricular premature beats (VPB), in control, with or without pairs (P) or nonsustained VT (NSVT; > 3 beats, > 100bpm). Drug efficacy criteria were; > or = 75% reduction in isolated VPB, reduction > or = 90% of P and NSVT. The effects of the Dg were evaluated in the global population, in patients with Chagas' disease, idiopathic arrhythmias and ischemic/hypertensive patients. RESULTS: Differences between control and placebo were NS. Isolated VPB; Dg was effective in 42% (38/90 patients) with a mean of Pb and Dg respectively of 11,770 +/- 13,818 and 1,043 +/- 1,554 (p < 0.001). Pairs: drug was effective in 48% (32/67 patients) with a mean of Pb and Dg respectively of 439 +/- 586 and 27 +/- 52 (p < 0.001). NSVT: drug effectiveness was 53% (19/36 patients) with a mean of Pb and Dg respectively of 445 +/- 1,148 and 2.5 +/- 5.8 (p < 0.102). In patients with Chagas' disease, the reduction in VPB was 33% (13/39 patients), in pairs was 42+ (14/34) and in NSVT was 64% (12/22). In idiopathic patients the reduction of VPB was 53% (17/32 patients), in pairs was 50% (10/20) and in NSVT was 36% (4/11). In ischemic and hypertensive patients the reduction of VPB was 47% (7/15 patients) and 73% in pairs (8/11). CONCLUSION: In the present study, sotalol was effective in the control of nonsustained ventricular tachyarrhythmia, with minimal side-effects.

Estudo multicêntrico brasileiro da eficácia do sotalol em arritmias ventriculares / Brazilion Multicenter Study of Sotalol Effectiveness in Ventricular Arrhythmias

Objetivo - Avaliar através de ensaio clínico prospectivo, randomizado, duplo-cego cruzado contra placebo, a eficácia do sotalol na dose oral de 320 miligramas diários em reduzir taquiarritmias ventriculares näo sustentadas (TVNS). Métodos - Foram avaliados em condiçöes de controle (Ct), placebo (Pb) e droga (Dg), 90 portadores de um número médio maior ou igual a 50 extra-sístole horárias (EV), com ou sem respostas pareadas (RP) e TVNS, registradas no Holter. Considerou-se a droga como efetiva, fren a uma reduçäo maior ou igual a 75 por cento das EV e maior ou igual a 90 por cento das RP e TVNS. Avaliaram-se os resultados globais e os observados em doenças específicas, incluindo a cardiopatia chagásica crônica, arritmias ventriculares idiopáticas e doença coronariana e hipertensiva sistêmica. Resultados - Näo ocorreram diferenças significativas entre Ct e Pb. Globalmente, a droga reduziu as EV em 42 por cento (38/90 pacientes), as RP em 48 por cento (32/67 e as TVNS em 53 por cento (19/36), com méis respectivas entre Pb e Dg de 11.770 mais ou menos 13.818 para 1.043 mais ou menos 1.554 nas EV (p menor a 0,001); de 439 mais ou menos 586 para 27 mais ou menos 52 nas RP (p menor a 0,001) e de 445 mais ou menos 1.147 para 2,5 mais ou menos 5,8 nas TVNS (p menor a 0,102). Nos chagásicos, reduçäo das EV de 33 por cento (13/39 pacientes), das RP em 42 por cento (14/34) e das TVNS em 64 por cento (12/22). Nos indiopáticos, a reduçäo das EV foi de 53 por cento (17/32 pacientes), das RP de 50 por cento (0/0) e das TVNS de 36 por cento (4/11). Nos isquêmicos e/ou hipertensos, a reduçào das EV foi de 47 por cento (7/15 pacientes) e de 73 por cento nas RP (8/11). Conclusäo - Na populaçäo estudada e na dose indicada, o sotalol mostrou ser um fármaco efetivo para controle de TVNS, apresentando mínimos efeitos colaterais.

Cibenzoline transforms random re-entry into ordered re-entry in the atria.

The goal of this study was to test the hypothesis that class I drugs modify the electrophysiological substrate of atrial fibrillation. The effects of a single intravenous dose (1.4 +/- 0.3 mg.kg-1) of the new class I drug, cibenzoline, were studied in 20 patients with spontaneous (n = 11) or induced (n = 9) atrial fibrillation, during an electrophysiological study. In one additional patient with chronic atrial fibrillation, the effects of a single intravenous dose of 2 mg.kg-1 of cibenzoline were studied intra-operatively before undergoing a 'corridor' operation. High resolution epicardial mapping (248 channels) was used to reconstruct the atrial activation patterns before and after administration of the drug. In 18 out of 20 patients administration of cibenzoline resulted in conversion of atrial fibrillation into regular monomorphic atrial tachycardia. In these 18 patients, the mean atrial cycle length was prolonged from 147 +/- 34 ms during atrial fibrillation to 302 +/- 34 ms after cibenzoline (P < 0.001). In eight out of the 18 patients, spontaneous (n = 3) or pacing induced (n = 5) conversion into sinus rhythm was observed after administration of the drug. In the patient undergoing the 'corridor' operation, epicardial mapping of both atria showed that the multiple wavelets present during atrial fibrillation fused into a single broad wavefront circulating counterclockwise around the caval veins after cibenzoline. In conclusion, cibenzoline transforms random re-entry into ordered re-entry in the atria. This effect seems related to the depression of conduction produced by the drug.

Clinical presentation and prognosis of left main coronary artery disease in the 1980s.

Clinical presentation and course were studied in 127 consecutive patients with angiographically proven left main coronary artery disease. Mean age was 62 (37-79) years. Thirteen patients (10%) had no history of chest pain, seven (5%) had atypical chest pain, and the remaining 107 (85%) typical angina pectoris. Eighty-two patients (65%) had unstable angina, 73 had suffered a myocardial infarction (MI) in the past, and 50 (68%) had post MI angina pectoris. The electrocardiogram was analysed in 102/125 patients during an episode of chest pain and also when they were without chest pain. Outside an episode of chest pain the ST segment was normal in 42 patients (32%), the T wave was normal in 50 patients (38%) and both the ST and T were normal in 33 patients (25%). During chest pain all patients had an abnormal ECG, the most frequent pattern being ST segment depression in leads V3, V4 and V5 (with maximal depression in V4), and ST segment elevation in leads V1 and aVR. The average number of leads with ST-T abnormalities was 6.4. A symptom-limited exercise test on a treadmill with 12-lead ECG monitoring was performed in 89 patients. The exercise test was abnormal in 88 patients (99%), most of whom (74 patients) were already in the first or second stage of the Bruce protocol. The most frequently observed abnormality was ST segment depression of 2 mm or more in leads V4, V5, and V6, and ST segment elevation in leads V1 and aVR. The systolic blood pressure during exercise fell or remained at the same level in 38 patients (43%).(ABSTRACT TRUNCATED AT 250 WORDS)

Longitudinal dissociation of atrioventricular accessory pathways.

Unusual properties of atrioventricular (AV) accessory pathways were found during electrophysiologic investigations in four patients (three men and one woman). Anterograde longitudinal dissociation of the accessory pathway was observed in two patients and retrograde longitudinal dissociation in two others. Two patients had an accessory pathway with a slow conduction time, one in anterograde direction and one in retrograde direction. These observations further expand our knowledge of the spectrum of electrophysiologic properties of accessory AV pathways.

Clinical and electrophysiologic characteristics of patients with antidromic circus movement tachycardia in the Wolff-Parkinson-White syndrome.

Antidromic circus movement tachycardia was documented in 36 of 345 consecutive patients with Wolff-Parkinson-White syndrome undergoing detailed electrophysiologic evaluation. Twenty-six patients were men and 10 were women (mean age +/- standard deviation 26 +/- 12 years [range 12 to 45]). Multiple accessory pathways were identified in 12 of these 36 patients (33%). Ten of the patients (67%) with clinically documented antidromic tachycardia had multiple accessory pathways. Dizziness and syncope occurred in 61 and 50% of patients with antidromic circus movement tachycardia. Six patients had clinical documentation of atrial fibrillation, and 4 patients (11%) were resuscitated from ventricular fibrillation. In the 36 patients, 56 distinct antidromic tachycardias were recorded and several different pathways were observed. Orthodromic tachycardia was the most frequently associated arrhythmia (72%). Dual atrioventricular nodal pathways were present in 12 patients (33%); however, atrioventricular nodal tachycardia could be initiated in only 2 of them. Interruption of the accessory pathway was successfully performed in all 20 patients undergoing surgery.

Reversibility of tachycardia-induced cardiomyopathy after cure of incessant supraventricular tachycardia.

Seven of 17 patients with incessant supraventricular tachycardia caused by an accessory pathway with a long retrograde conduction time were seen with symptoms or echocardiographic signs of a tachycardia-induced cardiomyopathy. Three patients were in New York Heart Association functional class II with dyspnea and four were in class III. Eight patients (six with tachycardia-induced cardiomyopathy) underwent surgery because of failure of medical treatment (including one patient in functional class I) and one underwent direct current catheter ablation of the atrioventricular (AV) node. In six patients echocardiograms recorded before and after the procedure were available. Before surgery or direct current ablation the mean left ventricular ejection fraction was 36.3 +/- 8.7%, the left ventricular end-diastolic diameter 55.7 +/- 7.6 mm and the left ventricular end-systolic diameter 44.3 +/- 7.8 mm. A mean of 21.6 +/- 6.8 months after the procedure the mean left ventricular ejection fraction increased to 58.6 +/- 8.0%, the left ventricular end-diastolic diameter decreased to 49.0 +/- 3.6 mm and the left ventricular end-systolic diameter decreased to 32.2 +/- 2.7 mm; all six patients were in functional class I. These results confirm that control of incessant tachycardia leads to a regression of symptoms and signs of cardiomyopathy and progressive normalization of the dimensions of the heart. Because of these findings, surgery should be considered early in patients with an accessory AV pathway and incessant tachycardia. The presence of a tachycardia-induced cardiomyopathy should therefore be an indication for surgery rather than a contraindication.

The electrocardiogram in patients with multiple accessory atrioventricular pathways.

The 12 lead electrocardiographic (ECG) findings were reviewed in 17 patients having two or more accessory pathways as documented during electrophysiologic study in all 17 patients and by intraoperative mapping in 8. Twelve patients had findings suggesting the presence of more than one atrioventricular (AV) pathway. These were 1) more than one P wave configuration during orthodromic circus movement tachycardia (four patients); 2) a "mismatch" between the location of the ventricular and atrial ends of the accessory pathway as assessed when comparing exclusive AV and ventriculoatrial conduction over the accessory pathway during antidromic and orthodromic circus movement tachycardia, respectively (seven patients); 3) atrial fibrillation showing more than one pre-excitation pattern (six patients); 4) a spontaneous change from orthodromic to antidromic circus movement tachycardia and vice versa (two patients); 5) a spontaneous change from one type of antidromic tachycardia to another (two patients); and 6) a change in pre-excitation pattern after administration of a drug that prolongs the anterograde refractory period of the accessory pathway (three patients). The retrospective nature of this study does not allow conclusions as to the true value of the ECG in predicting the presence of more than one accessory pathway. This issue needs to be evaluated in a prospective study.

Diagnosis and treatment of patients with accessory pathways.

Of the accessory pathways, partially or totally bypassing the atrio-ventricular conduction system, the bundle of Kent is the most common type. The electrocardiographic (ECG) expression of preexcitation depends upon the contribution of the activation fronts over the AV node and the accessory pathway. From the polarity of the delta wave in the surface ECG and from the behavior during electrophysiologic study, the location of the accessory pathway can be derived. The presence of an accessory pathway may induce circus movement tachycardia and, in case of atrial fibrillation, high ventricular rates possibly leading to sudden death. Noninvasive techniques are able to identify the patient at high risk. Treatment modalities are pharmacologic or surgical, whereas ablation techniques are still under investigation.