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Maximal exercise tolerance in chronic congestive heart failure. Relationship to resting left ventricular function
E S Carell1, S Murali, D S Schulman
1Division of Cardiology, University of Pittsburgh School of Medicine, PA.
Chest
|December 1, 1994
Summary
Resting heart function tests poorly predict exercise capacity in cardiomyopathy. However, peak systolic ejection rate and early diastolic filling may predict exercise tolerance in ischemic cardiomyopathy patients.
Area of Science:
- Cardiology
- Nuclear Medicine
- Exercise Physiology
Background:
- Chronic heart failure (CHF) significantly impairs exercise capacity.
- Left ventricular (LV) systolic and diastolic dysfunction are key features of CHF.
- Predicting exercise tolerance in cardiomyopathy is crucial for patient management.
Purpose of the Study:
- To evaluate the relationship between maximal exercise tolerance and resting radionuclide indexes of LV systolic and diastolic function.
- To determine if these indexes can predict exercise capacity in patients with ischemic and idiopathic cardiomyopathy.
Main Methods:
- Radionuclide ventriculography was used to measure LV ejection fraction, peak systolic ejection rate, peak diastolic filling rate, and fractional filling in early diastole.
- Symptom-limited exercise testing with on-line oxygen consumption (VO2max) measurement was performed.
- Patients were categorized into ischemic (n=20) and idiopathic (n=44) cardiomyopathy groups with NYHA class 2-4 CHF.
Main Results:
- In ischemic cardiomyopathy, only peak systolic ejection rate showed a modest correlation with VO2max.
- Ischemic patients with marked exercise intolerance had significantly lower peak systolic ejection rate, peak diastolic filling rate, and fractional filling in early diastole.
- In idiopathic cardiomyopathy, no radionuclide indexes correlated well with VO2max, and all indexes were similar between exercise-tolerant and intolerant groups.
Conclusions:
- Resting LV ejection fraction is a poor predictor of maximal exercise capacity in both ischemic and idiopathic cardiomyopathy.
- Resting peak systolic ejection rate, peak diastolic filling rate, and fractional filling in early diastole may predict exercise tolerance in ischemic cardiomyopathy but not in idiopathic cardiomyopathy.