Predictors of advanced His-Purkinje conduction disturbances in patients with unexplained syncope and bundle branch
Stéphane Boulé1, Aïcha Ouadah2, Carole Langlois3
1Lille University Hospital, Department of Cardiovascular Medicine, Lille, France.
Insights
For patients with syncope and bundle branch block (BBB), first-degree atrioventricular block and left posterior fascicular block (LPFB) predict advanced His-Purkinje conduction disturbances (HPCDs). Electrophysiological studies remain crucial for assessing pacemaker needs.
Area of Science:
- Cardiology
- Electrophysiology
- Medical Diagnostics
Background:
- Syncope and bundle branch block (BBB) require careful evaluation.
- Electrophysiological study (EPS) outcomes may vary based on electrocardiographic (ECG) patterns.
- Identifying predictors of advanced His-Purkinje conduction disturbances (HPCDs) is crucial.
Purpose of the Study:
- To identify predictors of advanced HPCDs in patients with syncope and BBB.
- To correlate ECG findings with HPCDs identified during EPS.
Main Methods:
- Retrospective multicenter study of 171 patients with syncope and BBB (QRS duration ≥ 120 ms).
- Patients underwent electrophysiological studies (EPS).
- HPCD diagnosis based on His-ventricular interval ≥ 70 ms or block during pacing/pharmacological challenge.
Main Results:
- Advanced HPCD was found in 43% of patients.
- ECG features associated with HPCD included isolated right BBB, right BBB with left anterior fascicular block, left BBB, and right BBB with left posterior fascicular block (LPFB).
- Multivariate analysis identified first-degree atrioventricular block (OR 2.4) and LPFB (OR 4.8) as independent predictors of advanced HPCD.
Conclusions:
- First-degree atrioventricular block and LPFB increase the likelihood of HPCDs in syncope patients with BBB.
- No single ECG feature reliably predicts EPS outcomes.
- EPS remains essential for guiding pacemaker implantation decisions.
Background:
For patients presenting with syncope and bundle branch block (BBB), results during electrophysiological studies (EPS) might depend on the electrocardiographic pattern of conduction disturbances. We sought to identify predictors of advanced His-Purkinje conduction disturbances (HPCDs) in these patients.
Methods:
In this retrospective multicentre study, patients were included who: (1) presented with unexplained syncope; (2) had BBB (QRS duration ≥ 120 ms); and (3) were investigated with EPS. HPCD was diagnosed if the baseline His-ventricular interval was ≥ 70 ms or if second- or third-degree His-Purkinje block was observed during atrial pacing or pharmacological challenge.
Results:
Of the 171 patients studied (72 ± 13 years, 64% male sex, mean left ventricular ejection fraction 57 ± 9%), advanced HPCD was found in 73 patients (43%). The following electrocardiographic features were associated with HPCD (P = 0.01): isolated right BBB (34.4%), right BBB with left anterior fascicular block (36.4%), left BBB (46.2%), and right BBB with left posterior fascicular block (LPFB, 78.6%). Multivariate analysis identified first-degree atrioventricular block (odds ratio, 2.4; 95% confidence interval, 1.2-4.7; P = 0.01) and LPFB (odds ratio, 4.8; 95% confidence interval, 1.3-18.5; P = 0.02) as the only 2 independent predictors of advanced HPCD.
Conclusions:
For patients presenting with syncope and BBB, first-degree atrioventricular block and LPFB increased the likelihood of finding HPCDs during EPS. However, no single electrocardiographic feature could consistently predict the outcome of EPS, so this investigation is still necessary in assessing the need for pacemaker implantation, irrespective of the precise appearance of abnormalities on ECG.
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