Key result
In patients with syncope and preexisting AV conduction disorders, preexisting bundle branch block predicted sinus arrest during ILR monitoring (53% vs 20% without BBB, P=0.03).
Why the study?
The feasibility of empiric pacemaker implantation in patients with preexisting AV conduction disorders remains debated, prompting investigation into syncope etiology and pacemaker need using ILR.
What is the etiology of syncope determined by ILR monitoring in patients with preexisting AV conduction disorders?
Observational (n=37)
What is the etiology of syncope determined by ILR monitoring in patients with preexisting AV conduction disorders?
Absolute Event Rate: 53% vs 20%
p-value: p=0.03
In patients with syncope and preexisting AV conduction disorders, ILR monitoring reveals that asystole is the prevailing mechanism, with sinus arrest predicted by preexisting BBB and complete AV block predicted by preexisting first-degree AV block.
May warrant closer ILR surveillance for sinus arrest in syncope with BBB; hypothesis-generating and requires prospective validation.
BACKGROUND: The discussion about the feasibility of empiric pacemaker implantation in patients with preexisting atrioventricular (AV) conduction disorders continues. The aim of the study was to determine the etiology of syncope and the need for pacemaker insertion in patients with AV conduction impairment using implantable loop recorder (ILR). METHODS: ILR was implanted after negative diagnostic workup in 37 patients with syncope (24 men, 13 women, age 72 ± 10 years) and preexisting impairment of AV conduction. First-degree AV block (AVB I) was present in 26 patients, and bundle branch block (BBB) in 17 patients. RESULTS: ILR-based diagnosis was made in 28 patients (75%)-sinus arrest in 13 patients, complete AVB in 10 patients, and vasodepressor syncope in five patients. In patients with preexisting BBB, sinus arrest occurred during ILR monitoring significantly more frequently than in patients without BBB (53% vs 20%, P = .03). Complete AVB was significantly less common in patients with preexisting BBB than in patients without BBB (12% vs 40%, P = .04). On multivariate regression analysis, the only independent predictor of AVB occurrence during ILR monitoring was preexisting AVB I (P = .03). The only independent predictor of sinus arrest during ILR monitoring was preexisting BBB (P = .03). CONCLUSIONS: In patients with preexisting AV conduction disorders, prevailing syncopal mechanism during ILR monitoring was asystole. However, sinus arrest occurred more often than complete AVB and was predicted by preexisting BBB. Preexisting AVB was a predictor of complete AVB during ILR monitoring.
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Mitro et al. (2020) conducted an observational in Syncope with preexisting impairment of atrioventricular conduction (n=37). Preexisting bundle branch block (BBB) vs. No preexisting bundle branch block was evaluated on Sinus arrest during ILR monitoring (p=0.03). In patients with syncope and preexisting AV conduction disorders, preexisting bundle branch block predicted sinus arrest during ILR monitoring (53% vs 20% without BBB, P=0.03).
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