Indications for dual-chamber cardioverter defibrillators at implant and at1 year follow-up: a retrospective analysis in the single-chamber defibrillator era

Aim This retrospective four-centre study assessed the current indications f or dual-chamber implantable carctioverter defibrillators (ICDs) at implant and during a medium-term follow-up period in a roup of patients treated by single-chamber ICD in the pre dual-chamber ICD era. Methods and Results The study population consisted of 153 consecutive patie nts (127 males, mean age 58 +/- 6 years) treated by single-chamber ICD for ventricular tachycardia and/or ventricular fibrillation. Definite indicatio ns for having a dual-chamber ICD included the presence of sinus node dysfun ction and of second- or third-degree atrioventricular (AV) block, while pos sible indications were represented by paroxysmal atrial fibrillation or flu tter and first-degree AV block. At implant, dual-chamber ICD would appear d efinitely indicated in 10.5% of cases, and possibly indicated in an additio nal 17.5% of cases. During 12+/-10 months follow-up, such percentages remai ned stable (11 and 19.5%, respectively). Inappropriate ICD intervention was documented in five of 13 patients (38%), with episodes of paroxysmal atria l fibrillation or flutter. Conclusion In this non-selected study population, a dual-chamber ICD would have potentially benefited approximately 30% of the patients. During medium -term follow-up, there was no progression towards increasing dual-chamber I CD indications. The 15% cumulative incidence of paroxysmal atrial tachyarrh ythmias justifies the activation of dedicated detection algorithms. (Europa ce 2001; 3: 132-135) (C) 2001 The European Society of Cardiology.