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Left ventricular function and exercise tolerance in patients with type II diabetes mellitus
L Irace1, D Iarussi, I Guadagno
1Cardiology Medicine Institute, Medical School, II University of Naples, Italy.
Clinical Cardiology
|August 14, 1998
Summary
Diabetic patients with impaired left ventricular diastolic function have reduced exercise tolerance, even without systolic dysfunction. This suggests diastolic dysfunction limits the heart's ability to increase output during exercise.
Area of Science:
- Cardiology
- Diabetology
- Exercise Physiology
Background:
- Left ventricular (LV) preload influences exercise tolerance (ET), potentially by affecting the Maestrini-Starling mechanism.
- Reduced LV filling during diastole, common in diabetic patients, can impair ventricular function.
Purpose of the Study:
- To investigate the relationship between echocardiographic LV function indices and ET in type II diabetes mellitus (DM).
- To compare LV function and ET in diabetic patients with early exercise interruption versus those achieving maximal stress test.
Main Methods:
- Echocardiography (M-mode, 2D, Doppler) assessed LV function parameters.
- Ergometric stress test (EST) duration served as the ET index.
- Linear regression analysis correlated diastolic function parameters with ET.
Main Results:
- No significant correlation was found between ET and DM duration, heart rate, blood pressure, or ejection fraction (EF).
- Diastolic function parameters showed a significant correlation with ET in diabetic patients with early exercise interruption (Group A).
- No significant correlation between diastolic function and ET was observed in the control group (Group B).
Conclusions:
- Impaired LV relaxation in diabetic patients can negatively impact exercise tolerance.
- This effect occurs even in the absence of systolic ventricular dysfunction.
- Diastolic dysfunction may limit the heart's contractile reserve during exercise in diabetics.