Survival after shock therapy in implantable cardioverter-defibrillator and cardiac resynchronization therapy-defibrillator recipients according to rhythm shocked. The ALTITUDE survival by rhythm study. Journal of the American College of Cardiology Powell, B. D., Saxon, L. A., Boehmer, J. P., Day, J. D., Gilliam, F. R., Heidenreich, P. A., Jones, P. W., Rousseau, M. J., Hayes, D. L. 2013; 62 (18): 1674-1679


We sought to determine if the mortality risk associated with inappropriate ICD shocks is due to the underlying arrhythmia or the shock itself.Shocks delivered from ICDs are associated with increased mortality risk. It is unknown if all patients that experience inappropriate ICD shocks have an increased risk of death.We evaluated survival outcomes in ICD and CRT-D patients enrolled in the LATITUDE remote monitoring system through January 1, 2010. First shock episode rhythms from 3,809 patients who acutely survived the initial shock were adjudicated by seven electrophysiologists. Patients with a shock were matched to patients without a shock (n=3,630) by age at implant, implant year, gender, and device type.The mean age of the study group was 64±13 years, with 78% male. Compared to no shock, there was increased mortality in those who received their first shock for monomorphic ventricular tachycardia (HR 1.65, p<0.0001), ventricular fibrillation/polymorphic ventricular tachycardia (HR 2.10, p<0.0001), and atrial fibrillation/flutter (HR 1.61, p=0.003). In contrast, mortality following first shocks due to sinus tachycardia and supraventricular tachycardia (HR 0.97, p=0.86), and noise/artifact/oversensing (HR 0.91, p=0.76) was comparable to that in patients without a shock.Compared to no shock, those who received their first shock for ventricular rhythms and atrial fibrillation had an increased risk of death. There was no significant difference in survival after inappropriate shocks for sinus tachycardia or noise/artifact/oversensing. In this study, the adverse prognosis following first shock appears to be more related to the underlying arrhythmia than to an adverse effect from the shock itself.

View details for DOI 10.1016/j.jacc.2013.04.083

View details for PubMedID 23810882