Background: Despite a proven mortality benefit in primary prevention (PP) patients, the utilization of implantable cardioverter-defibrillators (ICD) and cardiac resynchronization therapy-defibrillators (CRT-D) remains low in many geographies. Purpose: The objective of this analysis was to examine the mortality benefit in PP patients by guideline-indicated device type: implantable cardioverter-defibrillator (ICD) and cardiac resynchronization therapy-defibrillator (CRT-D). Methods: Improve SCA was a prospective, non-randomized, non-blinded multicenter trial that enrolled patients from regions where ICD utilization is low. PP patient’s CRT-D or ICD eligibility was based upon the 2008 ACC/AHA/HRS and 2006 ESC guidelines. Mortality was assessed according to guideline-indicated device type comparing implanted and non-implanted patients. Cox proportional hazards methods were used, adjusting for known factors affecting mortality risk. Results: Among 2,618 PP patients followed for a mean of 20.8 ± 10.8 months, 1,073 were indicated for a CRT-D, and 1,545 were indicated for an ICD. PP CRT-D-indicated patients who received CRT-D therapy had a 58% risk reduction in mortality compared to those without implant (adjusted HR 0.42, 95% CI: 0.28-0.61, P<0.0001). PP patients with an ICD indication had a 43% risk reduction in mortality with an ICD implant compared with no implant (adjusted HR 0.57, 95% CI: 0.41-0.81, P=0.002). Conclusions: This analysis confirms the mortality benefit of adherence to guideline-indicated implantable defibrillation therapy for PP patients in geographies where ICD therapy was underutilized. These results affirm that medical practice should follow clinical guidelines when choosing therapy for PP patients who meet the respective defibrillator device implant indication.

Introduction: Previous studies on radiofrequency catheter ablation of premature ventricular complexes (PVCs) arising from the left ventricle (LV) papillary muscles (PM) show a modest procedural success rate with higher recurrence rate. This study explored the utility of using a multipolar catheter for ablating the PM PVCs. Methods and Results: Endocardial mapping was performed via retrograde aortic approach using a steerable duodecapolar catheter in 6 patients and conventional point-by-point catheter in 5 patients, respectively. Compared with patients in point-by-point catheter group, duodecapolar catheter mapping demonstrated higher efficiency with an average procedure time and fluoroscopy time. The values of earliest activation time during mapping using duodecapolar catheter were significantly greater (32.3 ± 3.9 ms vs. 25.4 ± 2.8 ms). The mean number of ablation applications points in the duodecapolar catheter group was 6.8 ± 1.9 with an average overall ablation duration of 6.1 ± 3.0 minutes, which was significantly less compared to the point-by-point catheter group. There were no complications in duodecapolar catheter group whereas one cardiac tamponade occurred in the point-by-point catheter group. All 6 patients (100%) in the duodecapolar catheter group demonstrated acute successful ablation whereas only 3 of the 5 patients (60%) with point-by-point catheter ablation succeeded, and the intermediate success rate remained the same after an average follow-up of 9.7 ± 3.2 months. Conclusions: Mapping and ablation of PM PVCs using a duodecapolar catheter facilitated identification of earliest activation potentials and pace mapping, and demonstrated a high success rate during follow-up when compared to conventional mapping techniques.