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Left axis deviation: diagnostic contribution of stress testing and post-exercise systolic time intervals
Chest
|April 1, 1976
Summary
Left axis deviation (LAD) may indicate left ventricular dysfunction. Abnormal systolic time intervals (STIs) during exercise testing suggest potential underlying heart disease in individuals with LAD.
Area of Science:
- Cardiology
- Exercise Physiology
Background:
- Left axis deviation (LAD) is a common ECG finding.
- Its clinical significance, especially regarding cardiac function, requires further investigation.
Purpose of the Study:
- To assess the cardiac response to exercise in individuals with LAD using systolic time intervals (STIs).
- To determine if abnormal STIs correlate with left ventricular dysfunction in this population.
Main Methods:
- Investigated 10 subjects with LAD and 8 controls using graded upright bicycle ergometry.
- Measured resting and post-exercise systolic time intervals (STIs), including corrected left ventricular ejection time (LVETc).
- Defined abnormal STI response as a deltaLVETc of ≥ 8 msecs from rest to post-exercise.
Main Results:
- Subjects with LAD exhibited prolonged LVETc post-exercise compared to controls.
- An abnormal STI response (deltaLVETc ≥ 8 msecs) was observed, suggesting potential cardiac stress.
Conclusions:
- Exercise-induced changes in STIs may reveal latent left ventricular dysfunction in patients with isolated LAD.
- Abnormal STI response during ergometry could indicate underlying organic heart disease in individuals with LAD.