Apical rocking is predictive of response to cardiac resynchronization therapy

Identification of patients who will benefit from cardiac resynchronization therapy (CRT) is challenging. "Apical rocking" is frequently observed in asynchronously contracting ventricles and small studies suggested that it may predict CRT response. We assessed the predictive value of LV apical rocking on echocardiographic and clinical response to CRT in a large cohort of patients treated with CRT. Echocardiography was performed in 137 consecutive patients prior to CRT, and repeated during follow-up. Apical rocking was defined as motion of the left ventricular (LV) apical myocardium perpendicular to the LV long axis. Echocardiographic response to CRT was defined as a reduction in LV end-systolic volume ≥15% and clinical response as survival without heart failure hospitalization. All echocardiograms were assessed by independent cardiologists, blinded for baseline, clinical and follow-up data. Multivariable analyses were performed to adjust for potential confounders. Mean echocardiographic and clinical follow-up was 22 ± 8 and 57 ± 12 months respectively. Apical rocking was present in 49% of the patients. Apical rocking was more common in females, younger patients, and in patients with non-ischemic cardiomyopathy. Echocardiographic response to CRT was observed in 69%, clinical response in 77% of the patients. Apical rocking was associated with both echocardiographic response (OR 10.77, 95% CI 4.12-28.13) and clinical response to CRT (HR 2.73, 95% CI 1.26-5.91). Also after multivariable analyses, apical rocking was associated with both echocardiographic (OR 9.97, 95% CI 3.48-28.59) and clinical response to CRT (HR 2.13, 95% CI 0.94-4.83). Apical rocking is independently associated with both echocardiographic and clinical response to CRT.