Ventricular arrhythmias and the role of antitachycardia pacing in patients with electrical heart disease and hypertrophic cardiomyopathy

Background: Whether it is reasonable to program ATP in patients with electrical heart disease (EHD) or hypertrophic cardiomyopathy (HCM) is not thoroughly clarified. Aim of the study was to define the types of ventricular arrhythmias and evaluate the safety and efficacy of ATP activation in these patients. Methods and results: A total of 154 patients (53.9 % male, 64.9 % secondary prevention) with EHD or HCM, who had an implanted cardioverter defibrillator (ICD) with ATP activated, were included in this retrospective analysis; comprising a median of 65.0 months of follow-up. In 39/154 (25.3 %) patients appropriate ICD therapy was delivered during the follow-up. Patients with HCM had a significantly higher incidence rate of monomorphic VTs than patients with EHD (0.21 versus 0.01 per month, 0 < 0.001). ATP terminated monomorphic VT with an efficacy of 88,2 % in 94.9 % of the occurring episodes. The incidence rate per month of torsade de pointes (TdP) tachycardia and VF was significantly higher in patients with EHD versus HCM (0.04 vs. 0.001, p=<0.001; 0.06 vs. 0.007, p=<0.001). The termination of TdP tachycardia and VF was associated with ATP in 14.0 % and 0 % (ATP efficacy of 28.3 % and 0 % respectively). The implantation for secondary prevention was associated with the occurrence of appropriate ICD therapy during the follow-up period (OR 3.94 [95%CI 1.53-10.14], p = 0.005). Conclusion: Ventricular tachycardias in patients with HCM are primarily monomorphic and can be effectively terminated with ATP. In patients with EHD, TdP tachycardias and VF occur more frequently and are preferentially terminated by ICD shock.