Impact of Q wave in synthesized V7-9 lead on long-term outcomes after cardiac resynchronization therapy

Background: To investigate the relationship between the Q wave in synthesized V7-9 leads of a baseline electro-cardiogram and clinical outcomes in patients with heart failure after cardiac resynchronization therapy (CRT) device implantation. Methods: Consecutive patients with heart failure and a left ventricular (LV) ejection fraction <35 % were retrospec-tively analyzed. Patients with Q waves in the synthesized V7-9 lead were defined as the qV7-9 group and those without Q waves in the synthesized V7-9 lead were defined as the non-qV7-9 group. Multivariate analysis was per-formed to compare all-cause mortality and incidence of hospitalization for heart failure between the two groups. Results: We included 108 eligible patients. Twenty-nine patients were classified into the qV7-9 group and 79 pa-tients were classified into the non-qV7-9 group. There were 22 patients (20 %) with ischemic etiology, 67 (62 %) with New York Heart Association functional class II or III heart failure, and 91 (84 %) with a defibrillator. The pres-ence of Q waves in the synthesized V7-9 lead was significantly associated with worse outcomes, even with optimal medical treatment (adjusted hazard ratio, 2.1; 95 % confidence interval, 1.16-3.72; p = 0.03). Conclusion: In patients with heart failure and an LV ejection fraction of <35 %, the presence of Q waves in the syn-thetic V7-9 lead was associated with increased all-cause mortality and incidence of hospitalization after CRT device implantation.& COPY; 2023 Japanese College of Cardiology. Published by Elsevier Ltd.