Effectiveness of cardiac resynchronisation therapy in patients with echocardiographic evidence of mechanical dyssynchrony

Abstract

Cardiac resynchronisation therapy has proven to be effective in refractory heart failure (HF) patients with QRS >120-130 ms. Therefore, the aim of our study was to verify the long-term effectiveness of cardiac resynchronisation therapy in HF patients with echocardiographic evidence of mechanical asynchrony regardless of QRS duration. One hundred and six patients with New York Heart Association class II-IV HF and echocardiographic documentation of interventricular and intraventricular asynchrony underwent biventricular stimulation. A clinical and functional evaluation was performed at baseline, 1, 3, 6 months, and every 6 months thereafter. After a median follow-up of 16 months, a significant improvement was noted in ejection fraction, left ventricular diameters, mitral regurgitation jet area, interventricular and intraventricular echocardiographic indexes of asynchrony, and the 6-min walking distance (P < 0.001 for all). Death rates for all causes and for cardiac causes were 18.2 (95% confidence interval 12.8-25.9) and 13.5 (95% confidence interval 9.0-20.3) per 100 person-years, respectively. Patients in New York Heart Association class IV had an almost three-fold increase in risk of dying as compared to class II-III (hazard ratio 2.97, 95% confidence interval 1.30-6.79). Interventricular and intraventricular asynchrony at echocardiography may be useful in identifying HF patients suitable for cardiac resynchronisation therapy, with results comparable to those obtained with QRS duration selection criteria.