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Clinical and electrophysiologic findings in acute ischemic intraHisian bundle-branch block
J Cortadellas1, J Cinca, A Moya
1Servicio de Cardiología, Hospital General, Ciudad Sanitaria Valle Hebrón, Barcelona, Spain.
Insights
Acute ischemic right bundle-branch block (RBBB) in patients with large myocardial infarctions often leads to serious complications like ventricular arrhythmias and high mortality. Spontaneous recovery of RBBB is rare, necessitating careful monitoring and management.
Area of Science:
- Cardiology
- Electrophysiology
- Internal Medicine
Background:
- Acute ischemic right bundle-branch block (RBBB) can occur after myocardial infarction.
- Its association with significant cardiac events and mortality requires further investigation.
Purpose of the Study:
- To analyze the clinical and electrophysiologic features of acute ischemic RBBB.
- To assess the reversibility of RBBB with His bundle pacing.
- To evaluate the outcomes in patients with acute ischemic RBBB.
Main Methods:
- Analysis of nine patients with acute ischemic RBBB and large anterior myocardial infarctions.
- Electrophysiologic studies including HV intervals.
- Clinical follow-up for a mean of 26 months.
Main Results:
- RBBB occurred within 48 hours of infarction, often with left fascicular block.
- HV intervals were normal, but three patients progressed to complete atrioventricular block.
- High incidence of ventricular tachycardia (2/9), ventricular fibrillation (5/9), and mortality (4/9, 3 sudden deaths).
- RBBB resolved spontaneously in only one patient.
Conclusions:
- Acute ischemic intraHisian RBBB is associated with massive myocardial infarctions.
- It frequently presents with ventricular arrhythmias and carries a high mortality rate.
- Spontaneous resolution of RBBB is uncommon, and His-Purkinje conduction may appear normal initially.
Abstract:
Clinical and electrophysiologic features of acute ischemic right bundle-branch block (RBBB) that are reversible by His bundle pacing were analyzed in nine patients. All had large anterior myocardial infarctions (mean peak CK-MB = 185 +/- 71 IU/l), and six showed increased pulmonary capillary pressures. The RBBB occurred within 48 hours of infarction, and in six patients it was associated with left fascicular block. The HV intervals that were measured 1 to 4 days after infarction were normal in all patients. Progression to complete atrioventricular (AV) block occurred in three patients, and one patient required permanent cardiac pacing. Sustained ventricular tachycardia developed in two patients, and ventricular fibrillation developed in five. During a mean follow-up period of 26 months, four patients died (three of them suddenly). The RBBB disappeared in only one case. Acute ischemic intraHisian RBBB occurred in the setting of massive myocardial infarctions complicated by ventricular tachycardia or fibrillation and by a high mortality rate during the follow-up period. The RBBB rarely reverted spontaneously, and the His-Purkinje conduction time was frequently normal.