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Exercise-induced intranodal atrioventricular block
Mi-Youn Park1, Woo-Seung Shin, Byung-Ju Shim
1Division of Cardiology, Department of Internal Medicine, Pohang St. Mary's Hospital, Pohang, Korea.
Korean Circulation Journal
|November 22, 2012
Summary
This study details a rare case of exercise-induced complete atrioventricular (AV) block in a woman with normal resting AV conduction. Pacemaker implantation resolved her symptoms of dizziness and dyspnea.
Area of Science:
- Cardiology
- Electrophysiology
- Internal Medicine
Background:
- Exercise-induced atrioventricular (AV) block is uncommon, particularly in individuals with normal resting AV conduction.
- Patients may present with effort-related symptoms like dizziness and dyspnea.
Purpose of the Study:
- To report a rare case of exercise-induced complete AV block.
- To investigate the underlying electrophysiological mechanisms.
Main Methods:
- Case report of a 67-year-old woman.
- Treadmill exercise testing.
- Electrocardiography, echocardiography, coronary angiography, and electrophysiological studies.
Main Results:
- The patient developed complete AV block during treadmill testing at a sinus rate of 90 bpm.
- Electrophysiological studies revealed rate-dependent intranodal AV block.
- Permanent dual-chamber pacemaker implantation led to symptom resolution.
Conclusions:
- Exercise can unmask latent AV conduction abnormalities.
- Rate-dependent intranodal AV block can manifest during exertion.
- Pacemaker implantation is an effective treatment for symptomatic exercise-induced AV block.
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