Management of older patients with unexplained, recurrent, traumatic syncope and bifascicular block: Implantable loop recorder versus empiric pacemaker implantation-Results of a propensity-matched analysis

Abstract

Background: In patients with unexplained syncope and bifascicular block (BFB), syncope may be caused by intermittent atrioventricular (AV) block. When a correlation between syncope and bradyarrhythmia is not documented in these patients, 2 alternative management strategies can be adopted: (1) empiric pacemaker (PM) implantation or (2) long-term continuous electrocardiographic monitoring by implantable loop recorder (ILR).

Objective: The purpose of this study was to compare the risk of syncope recurrence associated with empiric PM implantation or ILR monitoring.

Methods: A prospective, multicenter, observational study enrolled consecutive patients with unexplained, recurrent, traumatic syncope and BFB who underwent ILR monitoring or empiric PM implantation. The risk and causes of syncope recurrence were assessed and compared between the 2 groups. Individual 1:1 propensity matching of baseline characteristics was performed.

Results: A total of 309 consecutive patients (age 77.2 ± 12.2 years; 60.8% male) were enrolled. Propensity matching yielded 89 matched pairs. After median follow-up of 33 months, empiric PM implantation was associated with a significantly lower risk of syncope recurrence than ILR monitoring (19.1 vs 46.1%; P <.001). A total of 35 patients (39.3%) who underwent ILR monitoring developed bradyarrhythmias (68.6% paroxysmal AV block) requiring PM implantation during follow-up. Excluding bradyarrhythmic syncope, the most frequent causes of syncope recurrence in both study groups were reflex syncope and orthostatic hypotension.

Conclusion: In patients with unexplained, recurrent, traumatic syncope and BFB, empiric PM implantation significantly reduced the risk of syncope recurrence in comparison with ILR monitoring. A high rate of patients who underwent ILR monitoring developed bradyarrhythmias requiring PM implantation.

Keywords: Bifascicular block; Bradyarrhythmia; Empiric pacemaker implantation; Implantable loop recorder; Insertable cardiac monitor; Pacemaker; Traumatic syncope; Unexplained syncope.