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Effects of left ventricular diastolic dysfunction on exercise capacity three to six weeks after acute myocardial
F Yuasa1, T Sumimoto, M Takeuchi
1Second Department of Internal Medicine, Kansai Medical University, Osaka, Japan.
Insights
Left ventricular diastolic dysfunction significantly impairs exercise capacity in patients post-myocardial infarction. Diastolic dysfunction, measured by delta PAWP/delta EDV, negatively impacts peak oxygen consumption and cardiac output.
Area of Science:
- Cardiology
- Cardiovascular Physiology
- Exercise Physiology
Background:
- Left ventricular (LV) diastolic dysfunction is a common complication after myocardial infarction.
- Its impact on exercise capacity in this patient population requires further elucidation.
Purpose of the Study:
- To investigate the relationship between LV diastolic dysfunction and exercise capacity in patients with recent myocardial infarction.
- To identify hemodynamic and radionuclide predictors of exercise limitation.
Main Methods:
- Fifty patients with recent myocardial infarction underwent assessment of hemodynamic and radionuclide responses at rest and during exercise.
- Left ventricular diastolic function was assessed using the delta pulmonary arterial wedge pressure (PAWP) to delta LV end-diastolic volume (EDV) ratio (delta PAWP/delta EDV).
- Patients were stratified into two groups based on peak oxygen consumption (VO2).
Main Results:
- The delta PAWP/delta EDV ratio showed negative correlations with peak VO2, cardiac output, and stroke volume.
- Patients with lower peak VO2 (group II) exhibited significantly higher delta PAWP/delta EDV compared to those with higher peak VO2 (group I).
- Group II also demonstrated reduced end-diastolic volume and stroke volume, and increased pulmonary arterial wedge pressure at peak exercise.
Conclusions:
- Left ventricular diastolic dysfunction plays a crucial role in limiting exercise capacity in patients recovering from myocardial infarction.
- Diastolic dysfunction is a significant determinant of reduced exercise tolerance, independent of systolic function in this cohort.
- Targeting diastolic dysfunction may improve exercise capacity in post-myocardial infarction patients.
Abstract:
To examine the effects of left ventricular (LV) diastolic dysfunction on exercise capacity, hemodynamic and radionuclide responses were measured at rest and during exercise in 50 patients with recent myocardial infarction. The ratio of an increase in pulmonary arterial wedge pressure (PAWP) to an increase in LV end-diastolic volume (EDV) from rest to peak exercise (delta PAWP/delta EDV) was used as an index of LV diastolic function, delta PAWP/delta EDV had modest and negative correlations with peak oxygen consumption (VO2), cardiac output, and stroke volume in all patients. Among patients with peak VO2 > or = 20 ml/min/kg (group I, n = 24) and those with peak VO2 < 20 ml/min/kg (group II, n = 26), there were no differences between the 2 groups with regard to resting LV ejection fraction, EDV, PAWP, cardiac output, and stroke volume. Although there was no significant difference in LV ejection fraction at peak exercise, group II had significantly reduced EDV, increased PAWP, and decreased cardiac output and stroke volume than those in group I. As a result, delta PAWP/delta EDV was significantly higher in group II. These results suggest that LV diastolic dysfunction has a key role in determining exercise capacity in patients with reduced exercise capacity after recent myocardial infarction.