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Myocardial bridging as a cause of paroxysmal atrioventricular block
Insights
Exercise-induced paroxysmal atrioventricular block occurred in a young man. This was linked to systolic narrowing of the left anterior descending coronary artery, causing conduction system ischemia.
Area of Science:
- Cardiology
- Electrophysiology
- Sports Cardiology
Background:
- Paroxysmal atrioventricular (AV) block can present in young, healthy individuals.
- Comprehensive cardiac evaluation is crucial for identifying underlying causes.
- Exercise can unmask latent cardiac conditions.
Observation:
- A young man experienced paroxysmal atrioventricular block during exercise.
- Cardiac evaluation revealed systolic narrowing of the left anterior descending coronary artery.
- Radionuclide imaging showed reversible septal hypoperfusion during exercise.
Findings:
- The patient's symptoms were associated with specific coronary artery abnormalities.
- Exercise-induced ischemia of the cardiac conduction system was identified.
- Systolic milking of the left anterior descending coronary artery is implicated.
Implications:
- This case highlights a potential mechanism for exercise-induced AV block.
- Coronary artery anomalies should be considered in young athletes with conduction abnormalities.
- Understanding systolic milking may inform diagnosis and management of similar cases.
Abstract:
Paroxysmal atrioventricular (AV) block was induced by exercise in an otherwise healthy young man. The only abnormalities demonstrated at comprehensive cardiac evaluation were: 1) angiographic systolic narrowing of the left anterior descending coronary artery, and 2) reversible radionuclide hypoperfusion of the septum during exercise. It is postulated that ischemia of the conduction system due to systolic milking of the left anterior descending coronary artery was responsible for the paroxysmal AV block in this patient.