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Syncope induced by propranolol in hypertrophic cardiomyopathy
J C García-Rubira1, M Pavón, D Romero-Chacón
1Unidad Coronaria, Hospital Universitario Virgen Macarena, Sevilla, Spain.
International Journal of Cardiology
|June 1, 1991
Summary
Propranolol can cause syncope and atrioventricular block in patients with obstructive hypertrophic cardiomyopathy and pre-existing conduction abnormalities. Caution is advised when initiating treatment in these individuals.
Area of Science:
- Cardiology
- Electrophysiology
Background:
- Obstructive hypertrophic cardiomyopathy (HCM) is a genetic heart condition.
- Patients with HCM may have underlying atrioventricular (AV) conduction abnormalities.
Observation:
- A patient with obstructive HCM experienced syncope and AV block after the initial propranolol dose.
- Electrophysiologic study identified an intermittent advanced His-Purkinje block.
Findings:
- Propranolol can unmask or exacerbate AV conduction defects in susceptible HCM patients.
- Advanced His-Purkinje system block can occur with beta-blocker initiation.
Implications:
- Clinicians should carefully assess AV conduction in HCM patients before prescribing propranolol.
- Consider electrophysiologic evaluation in HCM patients with suspected conduction disease before beta-blocker therapy.