Ventricular sense response biventricular pacing effects on QRS narrowing of patients with the implanted cardiac resynchronization therapy device

Abstract

Cardiac resynchronization therapy (CRT) is one of the most successful treatments for heart failure. Nowadays, in the presence of spontaneous ventricular beats, the Ventricular R Sense Response (VSR) feature introduced for pacing and synchronization optimally by CRT. However, the effects of this feature have not been fully studied. Therefore, the present study was conducted to investigate the effect of VSR on QRS narrowing as a measure of response to CRT. Methods and materials: This study was performed as a pre- and post-intervention in patients who underwent CRT-D or CRT-P implantation from Medtronic factory in Tabriz Civil Hospital for one year after accurate diagnosis of heart failure by a cardiologist. After examining the patients in terms of demographic characteristics, comorbidity and underlying rhythm, the length of QRS was assessed in five groups, which included intrensic, simultaneous BiV pacing with and without VSR, and LV50 BiV pacing with and without VSR. Then the data were collected and entered into the statistical software SPSS version 22 for analysis. Results: Of the 31 patients studied, 17 (54.8%) were male and 14 (45.2%) were female. The average age was 56 years. Underlying rhythm was sinus rhythm in most patients (61.3%) and AF was present in 10 patients (32.3%). The average QRS duration in the 12 leads was generally 36.32 milliseconds (8±18) in the intrinsic mode, which was significantly shorter in the simultaneous BiV pacing mode than in the intrinsic mode (P value <0.05). However, no significant difference was observed in comparison with simultaneous BiV pacing mode without VSR with VSR mode (P value > 0.05). Also, no significant difference was observed in comparison with LV50 BiV pacing mode only with LV50 BiV pacing mode with VSR (P value > 0.05).