LONG-TERM RESULTS OF 43 PATIENTS WITH AUT OMATIC IMPLANTABLE DEFIBRILLATORS - ANALYSIS OF PREDICTIVE FACTORS OF THE FIRST SHOCK

In order to identify patients who will receive an electric shock after implantation of an automatic fibrillator, the relationship between th e time to the first shock and clinical and paraclinical characteristic s were studied in 43 patients treated at the Lyon Cardiological Hospit al between July 1987 and September 1991. The age of the patients was 4 9.5 +/- 16 years (mean + SD). Eighty two percent of patients were men and the average left ventricular ejection fraction was 38.5 +/- 16.8 % . Four patients died in the peri-operative period. The average follow- up of the survivors was 22 months. During this period, 21 patients (53 .8 %) received an appropriate electric shock. Three patients died. The causal role of a malignant ventricular arrhythmia is discussed in one case. A second patient, who never had automatic fibrillation, died of cardiac failure. Finally, the third patient died of non-cardiac patho logy. The 22 month actuarial survival rate was 86 %. The probability o f receiving an appropriate electric shock was 60 %. Analysis of clinic al and paraclinical features identified left ventricular dysfunction ( ejection fraction less than 38 %) and cardiac symptoms (Stage m dyspno ea of the NYHA classification) as being associated with earlier electr ic shocks. This association was even more clear cut in the groupe of p atients with previous myocardial infarction. Therefore, patients with implantable automatic defibrillators for malignant ventricular arrhyth mias receive appropriate electric shocks in over 50 % of cases. Patien ts with symptoms of cardiac failure and low ejection fraction are part icularly exposed especially when they have previous myocardial infarct ion.