(P130) PREDICTIVE VALUE OF CLINICAL VARIABLES FOR HYPOTENSIVE SYNCOPE IN PATIENTS WITH BIFASCICULAR BUNDLE BRANCH BLOCK

Background: Previous findings from the Syncope: Pacing or Recording in the Later Years (SPRITELY) trial revealed no significant difference in syncope recurrence among patients with bifascicular block (BFB) regardless of whether they received a pacemaker (PM) or an implantable cardiac monitor (ICM). However, whether baseline clinical variables can predict hypotensive syncope remains unknown. This SPRITELY substudy aims to determine whether baseline clinical characteristics can predict syncope recurrence in patients with bifascicular block who have undergone pacemaker implantation. Clinically, establishing an association between baseline clinical variables and syncope recurrence could aid in identifying patients unlikely to benefit from empiric pacing. Conversely, the absence of such an association would streamline clinical decision-making in syncope management.

METHODS AND RESULTS: We conducted as a retrospective analysis of the SPIRITELY trial, a randomized clinical trial where patients with syncope and bifascicular block were randomly assigned to receive either a pacemaker or implantable loop recorder as the initial management approach. Within the cohort of 60 patients who received a pacemaker, we examined 38 baseline clinical variables encompassing demographics, comorbidities, medications, syncopal history, and other clinical data to determine whether they associate with syncope outcomes. Univariable and multivariate analyses were performed, with significance set at P < 0.05. Among the 60 patients with pacemaker implantation, 12 (20%) experienced recurrent syncope. Univariable analysis identified the usage of angiotensin receptor blockers (ARB) and a composite variable consisting of a history of asystole, supraventricular tachycardia (SVT), or diabetes as statistically significant predictors of syncope recurrence (p = 0.042). However, in multivariate analysis, only the composite of history of asystole, SVT, or diabetes emerged as a significant predictor of syncope (p = 0.03). Notably, the presence of SVT or diabetes alone did not independently predict syncope recurrence.

Conclusion: Baseline clinical variables were generally poor predictors of syncopal outcomes in elderly patients with bifascicular bundle branch block and syncope. In this demographic of patients, baseline clinical variables do not reliably predict syncope recurrence and thus should not be used to guide syncope management.