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Trifascicular block progressing to complete AV block on exercise: a rare presentation demonstrating the usefulness of
Ranjan K Shetty1, Sumit Agarwal1, Naveen Chandra Ganiga Sanjeeva1
1Department of Cardiology, Kasturba Medical College, Manipal University, Manipal, Karnataka, India.
This study highlights exercise-induced complete atrioventricular (AV) block in a patient with trifascicular block. Pacemaker implantation resolved symptoms, demonstrating effective management for this rare condition.
Area of Science:
- Cardiology
- Electrophysiology
- Internal Medicine
Background:
- Trifascicular block, characterized by complete right bundle branch block and left anterior fascicular block, can predispose individuals to conduction abnormalities.
- Exercise can unmask underlying cardiac electrical instability, leading to symptomatic bradycardia or heart block.
Observation:
- Echocardiography showed no wall motion abnormalities.
- Exercise treadmill testing (Bruce protocol) provoked complete atrioventricular (AV) block and reproduced the patient's symptoms.
- Coronary angiography excluded an ischemic etiology for the exercise-induced AV block.
Findings:
- Exercise-induced complete AV block was diagnosed in a patient with pre-existing trifascicular block.
- Symptoms of dyspnea and giddiness were directly correlated with exercise-induced AV block.
Implications:
- Dual-chamber pacemaker (DDD) implantation effectively treated the patient's symptoms.
- This case underscores the utility of exercise stress testing in identifying exercise-induced AV block.
- Management with pacing provides a successful outcome for patients with exertional AV block and trifascicular disease.
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