HV interval cutoff should be different in women and men with syncope and bundle branch block

Abstract

Abstract Background Determining the optimal HV interval cutoff for predicting the need for pacemaker (PM) implantation has been a recent focus of research. Current ESC guidelines recommend HV > 70 msec based on initial studies; however, new data suggest that a cutoff of >60 msec could appropriately identify patients at high risk for requiring PM implantation. While previous studies have indicated that women with bundle branch block (BBB) have a lower risk of AV block (AVB), gender differences in the optimal cutoff for considering a positive EPS have not been thoroughly investigated. Methods This cohort study included consecutive patients with unexplained syncope and BBB, enrolled from January 2010 to October 2021, with a median follow-up time of 3 years. Patients underwent a stepwise workup protocol involving an electrophysiological study (EPS) and long-term follow-up with an implantable cardiac monitor (ICM). Results Of the 503 patients in the study, 185 (38%) were women. The median age was 78 years (IQR 71-83), the median LVEF was 58% (IQR 50-62), and 110 (22%) had ischemic heart disease. The ECG showed LBBB in 194 (39%) patients and RBBB in 287 (57%). Among these, 177 (35%) also had left anterior hemiblock. The median HV interval was 60 msec (IQR 52-73), and EPS was diagnostic in 252 (50%) patients, with the majority (221, 44%) for AVB. In 91 patients with initially negative EPS, a diagnosis was made during follow-up with an ICM, and in 35, AVB was documented. In patients with negative EPS, an HV interval >60 msec was associated with an increased risk of AVB during follow-up (HR 2.5, 95% CI 1.6-4). However, significant gender differences were found. The risk of AVB was 2.5 times higher in men (95% CI 1-6) (Figure 1). Furthermore, sensitivity, specificity, PPV, and NPV for the cutoff of 60 msec were 47%/84%/51%/82% in men and 21%/78%/21%/78% in women. The AUC to predict AVB was 0.72 (95% CI 0.6-0.8) in men and 0.51 (95% CI 0.4-0.6) in women (Figure 2). Conclusions In patients with initially negative EPS, an HV interval >60 msec was associated with a higher risk of AVB during follow-up; however, significant gender differences were observed in diagnostic accuracy. In women, a cutoff of HV interval >60 msec presented poor diagnostic accuracy compared to men. Moreover, the HV interval did not adequately predict the development of AVB in women with a basal HV interval <70 msec, suggesting it may not be suitable for considering PM implantation in female patients.FIGURE 1FIGURE 2