The Antitachycardia Pacing ICD: Impact on Patient Selection and Outcome

Implantable cardioverter defibrillators (ICD) currently undergoing clinical investigation incorporate antitachycardia pacing capabilities, but little is known about their effect on patient selection and outcome. The Bilitch registry database was reviewed to compare the 1,553 patients who initially received standard devices with the 242 patients initially implanted with antitachycardia pacing ICDs (ANT). Baseline characteristics including mean age, ejection fraction, sex, type of cardiac disease, and percent presenting with sudden cardiac death were reviewed. Cumulative first shock occurrence and survival from arrhythmic and ail cause mortality were calculated for the two groups. Results: Patient characteristics were similar in the two groups except that the ANT population had a greater male predominance and initially presented with a lower sudden cardiac death incidence (P < 0.05). Cumulative occurrence of first shock was significantly lower in the ANT group up to 24 months of follow-up (28% vs 36%, P < 0.05). ANT group survival from arrhythmic death (99% vs 96%) and all cause mortality (89% vs 94%) was significantly higher at 24 months of follow-up (P < 0.05). Conclusions: The addition of antitachycardia pacing to ICD therapy appears to significantly limit the occurrence of first ICD shock without adversely affecting mortality in a patient population similar to those implanted with standard ICDs.