Mortality and morbidity in cardiac resynchronization patients: impact of lead position, paced left ventricular QRS morphology and other characteristics on long-term outcome.

AIMS: To investigate the effect of implantation-related characteristics, especially lead position and left ventricular (LV)-paced QRS morphology, on long-term mortality and morbidity in cardiac resynchronization therapy (CRT) patients. METHODS AND
RESULTS: The study retrospectively analysed 362 consecutive patients who underwent CRT device implantation over a 6 year period. Pre-implantation, LV-only paced, and biventricularly paced 12-lead electrocardiograms were obtained. Left ventricular and right ventricular (RV) lead positions were determined using biplane fluoroscopy and roentgenograms. The Kaplan-Meier method was used to estimate the survival function for all-cause death/hospitalization and cardiovascular death/hospitalization. Univariate and multivariate Cox proportional hazards models were also applied. The mean follow-up time was 24.7 ± 16.9 months. There were 79 deaths (62 cardiovascular) and 99 unplanned hospitalizations (72 cardiovascular). One year and 2 year all-cause mortality rates were 8.5 and 18.0%, respectively. Electrocardiographic and fluoroscopic descriptors of the LV lead position were found to be predictors of mortality/morbidity (as were functional class, heart failure aetiology, hyponatremia, and chronic atrial fibrillation). In particular, the antero-apical pattern of LV-only paced QRS showed a hazard ratio (HR) of 1.8 in univariate and 1.7 in multivariate analysis for predicting all-cause death/hospitalization (P = 0.006). The apical/paraseptal LV lead position showed an HR of 2.1 in univariate and 1.9 in multivariate analysis for predicting cardiovascular death/hospitalization (P = 0.018).
CONCLUSION: To achieve better long-term outcomes in CRT patients the antero-apical pattern of LV QRS complexes and apical or paraseptal LV lead position should be avoided.