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Cardiac Resynchronization Therapy and QRS Axis. Background: Mildly symptomatic heart failure (HF) patients derive substantial clinical benefit from cardiac resynchronization therapy with defibrillator (CRT-D) as shown in MADIT-CRT. The presence of QRS axis deviation may influence response to CRT-D. The objective of this study was to determine whether QRS axis deviation will be associated with differential benefit from CRT-D. Methods : Baseline electrocardiograms of 1,820 patients from MADIT-CRT were evaluated for left axis deviation (LAD: quantitative QRS axis -30 to -90) or right axis deviation (RAD: QRS axis 90-180) in left bundle branch block (LBBB), right bundle branch block (RBBB), and nonspecific interventricular conduction delay QRS morphologies. The primary endpoints were the first occurrence of a HF event or death and the separate occurrence of all-cause mortality as in MADIT-CRT. Results: Among LBBB patients, those with LAD had a higher risk of primary events at 2 years than non-LAD patients (20% vs 16%; P = 0.024). The same was observed among RBBB patients (20% vs 10%; P = 0.05) but not in IVCD patients (22% vs 23%; P = NS). RAD did not convey any increased risk of the primary combined endpoint in any QRS morphology subgroup. When analyzing the benefit of CRT-D in the non-LBBB subgroups, there was no significant difference in hazard ratios for CRT-D versus ICD for either LAD or RAD. However, LBBB patients without LAD showed a trend toward greater benefit from CRT therapy than LBBB patients with LAD (HR for no LAD: 0.37, 95% CI: 0.26-0.53 and with LAD: 0.54, 95% CI: 0.36-0.79; P value for interaction = 0.18). Conclusions: LAD in non-LBBB patients (RBBB or IVCD) is not associated with an increased benefit from CRT. In LBBB patients, those without LAD seem to benefit more from CRT-D than those with LAD. (J Cardiovasc Electrophysiol, Vol. 24, pp. 442-448, April 2013) [ABSTRACT FROM AUTHOR]

Risk of Mortality for Ventricular Arrhythmia. Background: There are limited data regarding the incidence and prognostic significance of ventricular arrhythmias (VA) in ambulatory continuous flow left ventricular assist device (LVAD) patients. Methods: Sixty-one consecutive patients from November 1, 2006 through December 31, 2010 with an LVAD and implantable cardioverter defibrillator that survived to discharge from the LVAD implantation admission were studied. Follow-up began from date of discharge with both devices in situ and ended with death, transplant, on June 1, 2011. Pre-LVAD VA history was related to the primary endpoints of post-LVAD VA, mortality, and the combined endpoint of post-LVAD VA/mortality. Results: During a mean follow-up of 622 days 19 patients (31%) experienced VA (14 episodes of VT, 5 episodes of VF). Pre-LVAD VA was predictive of post-LVAD VA (hazard ratio [HR] 2.91, P = 0.026) and the combined post-LVAD VA/mortality endpoint (HR 2.70, P = 0.021) but only displayed a nonsignificant association with mortality (HR 2.30, P = 0.11). In multivariate analysis, pre-LVAD VA remained a significant predictor of post-LVAD VA (HR 2.84, P = 0.03) and the combined post-LVAD VA/mortality endpoint (HR 2.65, P = 0.025). Post-LVAD VA was the strongest univariate predictor of mortality (HR 13.92, P < 0.001) and remained so after multivariate adjustment (HR 9.69, P = 0.001). Post-LVAD VA occurred at a mean of 1 year from mortality events with 45% within 1 month. Conclusions: Pre-LVAD VA is a significant predictor of post-LVAD VA but not of mortality. VA in the continuous flow LVAD population carries a significant risk of mortality often within the first month. (J Cardiovasc Electrophysiol, Vol. 23, pp. 515-520, May 2012) [ABSTRACT FROM AUTHOR]