Early benefit of implantable cardioverter defibrillator therapy in patients waiting for cardiac transplantation.

The ICD can effectively recognize and treat ventricular arrhythmias that can lead to sudden death. Sudden death is a major problem in patients awaiting heart transplantation. We reviewed our experience with the ICD in patients with malignant ventricular arrhythmias waiting for cardiac transplantation. Nineteen patients were included. Seventeen were men, mean age was 54 +/- 11 years (range 17-66) and the left ventricular ejection fraction was 22% +/- 10% (range 9%-46%). After a mean follow-up of 6 +/- 5 months (range 1-20 months), 17 patients reached heart transplantation. One patient died and the other is waiting for a transplant. Before transplantation 71% of patients received an appropriate discharge. The mean time to the first appropriate discharge was 2 +/- 2 months (range < 1-6 months), which was significantly shorter than the mean time to first discharge in the other patients (n = 182) receiving a defibrillator in our center (11 +/- 10 months; range 1-58 months) (P < 0.0004). In conclusion, cardiac transplantation candidates with life-threatening ventricular arrhythmias can effectively be protected against sudden arrhythmic death by ICD. These patients have a high incidence of appropriate shocks occurring very early after implantation.

Experience with implantable cardioverter defibrillator therapy in elderly patients.

AIM: Concern exists about the benefit of implantable defibrillator therapy in elderly patients. We assessed the utility of implantable defibrillator therapy and its effect on mortality in patients 70 years and older and compared results in this group to those in younger patients. METHODS AND RESULTS: Thirty-two out of 200 consecutive patients (16%) were 70 years or older at the time of implantation of a defibrillator. When comparing elderly to younger patients no significant differences were noted with respect to presenting arrhythmia, left ventricular ejection fraction or presence of an old myocardial infarction. Elderly patients had a higher prevalence of ischaemic heart disease, while in the younger group more patients had idiopathic ventricular tachycardia. Cumulative survival curves (Kaplan-Meier method) for all-cause mortality, sudden cardiac death and non-sudden cardiac death were constructed for elderly and younger patients. No significant differences for cumulative survival from all-cause mortality (75 vs 74%), sudden cardiac death (0 vs 4%) and non-sudden cardiac death (97 vs 93%) were found. The incidence of appropriate shocks during follow-up was comparable (65 vs 72%). CONCLUSION: Implantable defibrillator therapy was effective in preventing sudden cardiac death in the elderly. Total mortality was similar to younger patients at a follow-up of 19 +/- 14 and 25 +/- 19 months, respectively. Age itself should be no contraindication to implantable cardioverter defibrillator therapy.

[Right bundle-branch block, the elevation of the ST segment in V1 to V3 and sudden death: the diagnostic and therapeutic approach]. / Bloqueio de ramo direito, supradesnivelamento do segmento ST de V1 a V2 e morte súbita: abordagem diagnóstica e terapêutica.

In 1992, Brugada and Brugada described the "syndrome of right bundle branch block, persistent ST segment elevation and sudden death". This clinical and electrocardiographic entity, which occurs in patients with a structurally normal heart, has drawn the attention of many investigators. Nowadays, the occurrence of sudden death in otherwise asymptomatic patients with a typical ECG, and the transient normalization of the ECG in symptomatic patients, support the existence of asymptomatic and intermittent forms of this disease. The knowledge of these new forms and the modulation of the ECG pattern by administration of antiarrhythmic and autonomic drugs suggest that a functional abnormality of the electrical activity of the heart is responsible for this syndrome. The role of "M cells" in ventricular repolarization and in the occurrence of polymorphic ventricular arrhythmia suggests that these cells are the substrate for that electrical abnormality. Further studies are required to determine the appropriate therapeutic strategy for these patients. Until new information is available, the implantable cardioverter defibrillator is indicated in all symptomatic patients.

The value of DDD pacing in patients with an implantable cardioverter defibrillator.

Although the beneficial effects of DDD pacing are well known, currently available ICDs provide only fixed rate ventricular antibradycardia pacing. In a consecutive series of 139 patients with ICDs, we have analyzed the need for antibradycardia pacing and the indications for DDD pacing. We also report our initial experience with the Defender 9001 (ELA Medical, France) DDD-ICD. Out of 139 patients, 25 (18%) were in need of antibradycardia pacing. Ten patients already had a pacemaker at the time of ICD implantation and ten other patients had a conventional pacemaker indication at that time. Five patients became pacemaker dependent during a follow-up of 20 +/- 8 months. The disorders necessitating pacemaker therapy were high degree AV conduction disturbances in 72%, sick sinus syndrome in 12%, and AF with a slow ventricular response in 16% of patients. Based upon current indications, DDD pacing was indicated in 20 (80%) of 25 patients. The Defender 9001 DDD-ICD (ELA Medical) was used in two patients with ischemic cardiomyopathy and pacemaker syndrome with VVI pacing. Cardiac output during DDD pacing increased by 36% in one patient with an increase in VO2 max during exercise of 29%. The other patient showed an increase in cardiac output of 50% with DDD pacing, and, while unable to exercise with VVI pacing, had a VO2max of 24 mL/kg per minute during DDD pacing. Up to 18% of our ICD patients are in need of antibradycardia pacing. Of these pacemaker dependent patients, 80% have an indication for DDD pacing. Our first clinical experience with a DDD-ICD confirms the hemodynamic benefit of AV synchronous pacing in ICD patients with pacemaker syndrome.

Electrocardiographic identification of mid-septal accessory pathways in close proximity to the atrioventricular conduction system.

In order to identify ECG characteristics of overt mid-septal accessory pathways (APs) predictive of close proximity to the AV conduction system we analyzed data from patients who underwent successful RF catheter ablation of a mid-septal AP. Mean patient age was 31 +/- 16 years, and 13 were male. The 40 degrees right anterior oblique view was used to divide the mid-septal area into 3 zones: 1 (anterior portion); 2 (intermediate); and 3 (posterior portion). The 12-lead ECG was analyzed with regard to delta wave polarity and R/S transition in the precordial leads. The findings from patients ablated at zone 3 were compared to those at zones 1 and 2. All patients had a positive delta wave in the leads I, II, aVL, and negative delta wave in the leads III and aVR. The R/S transition occurred in lead V2 in 80% of patients. The delta wave in lead aVF was the only ECG characteristic that correlated with the AP ablation zone. Six of 8 patients ablated at zone 3 had a negative delta wave in lead aVF while 6 out of 7 patients ablated at zone 1 or 2 had a positive or isoelectric delta wave in lead aVF (P = 0.03). A positive or isoelectric delta wave in lead aVF identifies mid-septal AP in close proximity to the AV conduction system.