EXPERIENCES WITH IMPLANTABLE CARDIOVERTER -DEFIBRILLATORS OF NEWER GENERATION

In 71 patients with a mean age of 59 +/- 10 years and an ejection frac tion of 40 +/- 16%, a total of 78 cardioverter/defibrillators of a new er generation was implanted. The majority of the patients had coronary artery disease (n = 51). The indications for implantation were ventri cular fibrillation in 30, hemodynamically unstable ventricular tachyca rdia in 20, and both ventricular fibrillation and ventricular tachycar dia in 21 cases. In 33 of 35 attempted procedures a transvenous-endoca rdial implantation could be performed. After a mean follow-up of 20 +/ - 14 months, the total survival rate was 87.4% and total cardiac morta lity was 9.4 %. Adequate interventions occurred in 33 patients. 25 of them received shocks which were either accompanied with syncope/presyn cope or were given due to documented fast (> 230 bpm) tachyarrhythmic episodes. Of the remaining patients, the interventions were shocks in the setting of slower episodes in two or exclusively antitachycardia p acing in seven cases. In those individuals in whom antitachycardia pac ing could be optimized by several inductions and terminations of stabl e ventricular tachycardias at predischarge electrophysiological testin g, the success rate was 82 %. In a small number of patients (n = 11) w ithout documented and known ventricular tachycardias, an antitachycard ia program based on our experiences was blindly activated. During foll ow-up, 37 episodes were documented in four cases. In 57 % of these epi sodes, a shock was omitted because of successful antitachycardia pacin g. False triggering was noted in four patients, due to atrial fibrilla tion with a fast ventricular rate (n = 3) and sinus tachycardia (n = 1 ). Oversensing due to technical reasons occurred in four individuals, due to electrode fracture in one, and connection problems in three cas es. The whole majority of the episodes was of short duration (diverted shocks); in only three episodes (two cases), shocks were given. In th ose and in one patient with electrode fracture the surgical reinterven tion was necessary. Thus, due to several additional diagnostical and t herapeutical features of the cardioverter/defibrillators of newer gene ration the long-term therapy is more effective and safe and in case of antitachycardia pacing more comfortable to the patients.