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Early repolarization: normalization of the electrocardiogram with exercise as a clinically useful diagnostic feature
K A Spratt1, S M Borans, E L Michelson
1Department of Medicine, Hahnemann University Hospital, Philadelphia, Pennsylvania, USA.
The Journal of Invasive Cardiology
|September 5, 1995
Summary
Early repolarization, a normal ECG variant, typically resolves with exercise. This study found ECG normalization at approximately 106 bpm, suggesting a useful diagnostic tool for differentiating from cardiac injury.
Area of Science:
- Cardiology
- Electrocardiography
Background:
- Early repolarization is a common ECG variant that can mimic serious cardiac conditions like myocardial infarction.
- The resolution of early repolarization with increased heart rate is a debated phenomenon.
Purpose of the Study:
- To quantitatively and qualitatively evaluate the resolution of early repolarization with exercise.
- To assess the diagnostic utility of early repolarization in patients without cardiovascular disease.
Main Methods:
- Retrospective analysis of 25 patients with early repolarization and no risk factors (Group I), 28 with early repolarization and risk factors (Group IIA), and 28 controls (Group IIB).
- Exercise treadmill testing and radionuclide stress imaging were employed.
- Patients had normal ECGs and no history of cardiovascular disease.
Main Results:
- ST elevation in early repolarization most commonly occurred in lead V4.
- ECG normalization began with exercise, completing at an average heart rate of 106 bpm.
- Early repolarization predicted negative exercise tests and infrequent positive imaging studies in healthy individuals.
Conclusions:
- Progressive ST segment decrease and ECG normalization with mild exercise is a predictable response in patients with early repolarization and no cardiovascular history.
- This phenomenon can serve as a bedside diagnostic tool to differentiate early repolarization from acute myocardial infarction or pericarditis.
- Further prospective clinical trials are warranted to validate these findings.