Exercise stress echocardiography is superior to rest echocardiography in predicting left ventricular reverse remodelling and functional improvement after cardiac resynchronization therapy

Aims: Cardiac resynchronization therapy (CRT) improves functionalcapacity and survival in heart failure. However, one-third ofpatients fail to respond to CRT. Resting left ventricular (LV)dyssynchrony assessed by echocardiography (ECHO) showed discordantresults in identifying CRT responders. LV dyssynchrony can totallychange during exercise. Aim of this study was to evaluate whetherexercise dyssynchrony could select responders to CRT. Methods and results: Sixty-four patients scheduled for CRT implantation performedbicycle exercise ECHO in semi-supine position on an exercisetilting table before and 6 months after CRT implantation. TissueDoppler imaging (TDI) was acquired both at rest and during exerciseto detect LV mechanical dyssynchrony. Predictive values forCRT response were 70% for rest TDI and 89% for exercise TDI(P = 0.01). Exercise LV dyssynchrony was the only parameterindependently associated with follow-up improvement of restejection fraction and LV volume during multivariable analysis(P < 0.001). Functional improvement at 6-min walking testwas statistically higher in patients with exercise dyssynchrony(P = 0.005), and not different considering rest dyssynchrony(P = 0.30). Conclusion: Exercise intraventricular dyssynchrony assessed by exerciseTDI ECHO is a strong independent predictor of CRT response.It could be used to select candidates for CRT, thus reducingineffective implantations of biventricular pacemakers.