Beschreibung:
<jats:p> <jats:italic>Background:</jats:italic> Cardiac resynchronization therapy (CRT) is an established therapy for patients with severe heart failure and mechanical dyssynchrony. Response is only achieved in 60–70% of patients.</jats:p><jats:p> <jats:italic>Objectives:</jats:italic> To study exercise‐related factors predicting response to CRT.</jats:p><jats:p> <jats:italic>Methods:</jats:italic> We retrospectively examined consecutive patients in whom a CRT device was implanted. All underwent cardiopulmonary exercise testing prior to implantation and after 6 months. The occurrence of chronotropic incompetence and heart rates exceeding the upper rate of the device, thereby compromising biventricular stimulation, was studied. Response was defined as a decrease in LVESV of 10% or more after 6 months.</jats:p><jats:p> <jats:italic>Results:</jats:italic> We included 144 patients. After 6 months 86 (60%) patients were responders. Peak VO<jats:sub>2</jats:sub> significantly increased in responders. Chronotropic incompetence was more frequently seen in nonresponders (21 [36%] vs 9 [10%], P = 0.03), mostly in patients in SR. At moderate exercise, defined as 25% of the maximal exercise tolerance, that is, comparable to daily life exercise, nonresponders more frequently went above the upper rate of the device (13 [22%] vs 2 [3%], P < 0.0001), most of whom were patients in permanent AF. Multivariate analysis revealed heart rates not exceeding the upper rate of the device during moderate exercise (OR 15.8 [3.3–76.5], P = 0.001) and nonischemic cardiomyopathy (OR 2.4 [1.0–5.7], P = 0.04) as predictive for response.</jats:p><jats:p> <jats:italic>Conclusions:</jats:italic> Heart rate exceeding the upper rate during moderate exercise is an independent predictor for nonresponse to CRT in patients with AF, whereas chronotropic incompetence is a predictor for patients in SR.</jats:p>