Early right ventricular response to cardiac resynchronization therapy: impact on clinical outcomes.

Abstract

Right ventricular (RV) dysfunction has been associated with a worse outcome in heart failure patients undergoing CRT. However, evidence on the RV response to CRT is controversial and there are no data regarding the early effects of CRT on RV function (RVF). We sought to investigate whether a CRT device favourably influences the RVF acutely after implantation, impacting on long-term outcomes. Patients who successfully underwent CRT device implantation from January 2005 to January 2014 were retrospectively analysed. RV dysfunction was defined by an RV fractional area change <35%. Post-procedural echocardiographic evaluation was performed at a median time of 2 days (interquartile range 1-6 days). The primary endpoint was a composite of all-cause mortality and urgent heart transplantation. A total of 194 patients with available pre- and post-procedural RVF assessment were included. Sixty-two (32%) presented an impaired RVF before the procedure. Of them, 32% showed prompt normalization of RVF following CRT. This occurred in parallel with a large improvement in pulmonary arterial pressure, mitral regurgitation, E/E' ratio, and diastolic function. Pre-implantation independent predictors of early RVF normalization were LBBB (P = 0.034) and higher systolic blood pressure (P = 0.026). Improvement in RVF was independently associated with a better long-term prognosis at multivariable analysis [hazard ratio 0.124; 95% confidence interval 0.016-0.966, P = 0.04). Acute normalization of RVF can be observed after CRT along with haemodynamic improvement, and therefore can be used as an independent predictor of transplant-free survival.