Clinical Characteristics and Predictors of Super-Response to Cardiac Resynchronization Therapy: A Combination of Predictive Factors

Background Patients with greater improvement of cardiac function after cardiac resynchronization therapy (CRT) implantation are identified as "super-responders." However, it remains unclear which kind of preimplant assessments could accurately predict outcomes after CRT. Thus, we aimed to examine the essential predicting factors for super-response to CRT, and to construct an accurate predictable model. Methods We retrospectively analyzed the CRT patients who underwent implantation at Nagoya University Hospital. Super-responders are defined as those who show a relative reduction in left ventricular end-systolic volume ≥30% after 6 months of CRT. Results Eighty patients (mean age, 67.8 ± 10.2 years) were included. Twenty-two patients received upgrading procedure to CRT implantation. Six months after the implantation, 29 patients (36%) were super-responders. Multiple logistic regression analysis shows that consistent right ventricular pacing with a previous device (odds ratio [OR] 7.28, 95% confidence interval [CI] 1.52-34.9; P = 0.013), lack of prior history of ventricular arrhythmia (OR 5.32, 95% CI 1.52-18.6; P = 0.009), and smaller left atrial diameter (LAD) (OR 0.92, 95% CI 0.86-0.98; P = 0.014) are independent predictors for CRT super-responders. The use of a combination of these predictive factors could increase the certainty with which a greater response to CRT is predicted and the presence of such a combination could improve prognosis. Conclusion Greater response to biventricular pacing occurs more frequently in patients with consistent right ventricular pacing, lack of prior history of ventricular arrhythmia, and smaller LAD. An association between patient background characteristics and a super-response to CRT was also identified.