Re-worsening left ventricular ejection fraction after response to cardiac resynchronization therapy

Although cardiac resynchronization therapy (CRT) provided functional and clinical improvement in patients with heart failure (HF) and electrical intraventricular conduction disturbances, some patients had re-worsening left ventricular (LV) function after a favorable CRT response. We analyzed the clinical variables and cardiac outcomes associated with this re-worsening LV function after CRT.

In this study, 71 patients with CRT response who received CRT between 2006 and 2017 were included. CRT response was defined as a "≥ 10% improvement in LV ejection fraction (LVEF) on follow-up." Patients were classified into two groups: (i) persistent: (n = 48, 68%), defined as those with a CRT response and (ii) re-worsening: (n = 23, 32%), consisting of those who fell out of the definition of a CRT response after an initial CRT response.

Half of the patients in the re-worsening group failed to maintain a CRT response from two years upwards. A longer duration from HF diagnosis to CRT implantation, nonspecific intraventricular conduction delay (NIVCD) on electrocardiogram at CRT implantation, and a lower increased LVEF at initial CRT response were independent predictors for the re-worsening group. Patients in the re-worsening group had a higher incidence rate for HF hospitalization and cardiac deaths, compared with those in the persistent group.

One-third of CRT responders experienced re-worsening LVEF, which was associated with poor outcomes. CRT responders with NIVCD, longer HF duration, and a lower increased LVEF at initial CRT response should be monitored with caution.