SIGNIFICANCE OF SUPRAVENTRICULAR TACHYARRHYTHMIAS IN PATIENTS WITH IMPLANTED PACING CARDIOVERTER-DEFIBRILLATORS

Eighty-six patients were treated with an implantable cardioverter defi brillator (ICD) because of sustained ventricular tachycardia (VT) or v entricular fibrillation (VF). In 27 patients an epicardial system was used, in 59 patients a transvenous system with a subcutaneous patch el ectrode was implanted. During a mean follow-up time of 17 +/- 9 months , inappropriate activations of the ICD due to supraventricular tachyca rdia were documented by Holter monitoring in 14 patients (16%). In 8 p atients paroxysmal atrial fibrillation (AF), in 2 patients chronic AF, in 1 patient atrial flutter, and in 3 patients sinus tachycardia trig gered antitachycardia pacing functions (12 patients) or internal defib rillation (2 patients). In 3 patients (5%) VT was induced by inappropr iate antitachycardia pacing. In an additional 18 patients (21%) inappr opriate activation of antitachycardia functions due to atrial tachyarr hythmias were suspected based on telemetry readouts or the patient's h istory. Inappropriate activation of ICD therapy triggered by intermitt ent supraventricular tachyarrhythmias is common. Further improvements of detection algorithms for supraventricular tachycardia are required in future device generations.