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[Left ventricular diastolic pressure-volume relations during exercise (author's transl)]
Insights
Exercise impacts left ventricular diastolic function differently across various heart conditions. While normal and aortic insufficiency patients show preserved function, cardiomyopathies and aortic stenosis reveal impaired relaxation, similar to coronary artery disease with angina.
Area of Science:
- Cardiology
- Physiology
- Medical Imaging
Context:
- Left ventricular diastolic pressure-volume relations (PVR) are crucial for assessing heart function.
- Ergometer exercise provides a dynamic stressor to evaluate cardiac response.
- Understanding diastolic function changes during exercise is vital for diagnosing and managing heart disease.
Purpose:
- To analyze left ventricular diastolic pressure-volume relations (PVR) at rest and during exercise in patients with various cardiac conditions.
- To compare the effects of exercise on diastolic function in normal individuals and patients with coronary artery disease, congestive cardiomyopathy, aortic insufficiency, and pressure overload (aortic stenosis, coarctation of the aorta).
Summary:
- Diastolic PVR remained unchanged with exercise in normal and aortic insufficiency patients, with a significant decrease in the time constant of isovolumic relaxation (T).
- Coronary artery disease patients with angina showed an upward shift in diastolic PVR during exercise.
- Congestive cardiomyopathy and aortic stenosis patients exhibited upward shifts in diastolic PVR, with increased minimal rate of left ventricular pressure change (dp/dtmin) and prolonged T in aortic stenosis, suggesting disturbed ventricular relaxation.
Impact:
- Exercise-induced changes in diastolic PVR and relaxation time constants (T) can differentiate between normal and diseased states.
- Findings highlight impaired ventricular relaxation as a key factor in diastolic dysfunction during exercise in non-ischemic heart diseases.
- This study provides insights into the pathophysiology of diastolic dysfunction under stress, aiding in clinical assessment and therapeutic strategies.
Unlabelled:
Left ventricular diastolic pressure-volume relations (PVR) were analysed from biplane ventriculograms and simultaneous pressure measurements in 33 patients at rest (R) and during ergometer exercise (E) (8 normals [N], 8 patients with coronary artery disease [CAD], 8 patients with congestive cardiomyopathy [COCM], 5 patients with aortic insufficiency [AI] and 5 patients with pressure overload (4 with aortic stenosis [A-St.] and 1 coarctation of the aorta). In N and AI diastolic PVR was essentially unchanged with E, the time constant of isovolumic relaxation (T) decreased significantly (N: delta T = -24.4 +/- 11.6%, p less than 0.001; AI: delta T = -27.3 +/- 6.8%, p less than 0.005). In CAD diastolic PVR was shifted upwards in all cases with angina pectoris during E (7/8), minimal rate of left ventricular pressure change (dp/dtmin) and T did not change significantly. In COCM diastolic PVR was shifted upwards in 4 cases, while dp/dtmin increased significantly (R = -1107 +/- 327, E = -1508 +/- 626 mm Hg-s-1, p less than 0.05), T on the average was unchanged (R = 53 +/- 10.5, E = 51 +/- 14.2 msec). In A-St. in 3 of 4 cases diastolic PVR was significantly shifted upwards with E, dp/dtmin increased (R = -1633 +/- 93, E = -2093 +/- 170 mm Hg-s-1, p less than 0.001), T in contrast to N and AI was prolonged (R = 33.8 +/- 4, E = 39.9 +/- 1.9 msec).
Conclusion:
In N and AI diastolic ventricular function is not altered with exercise. In COCM and especially in A-St., however, there are similar alterations like in CAD with angina pectoris. Changes in T indicate that shifts of the PVR with exercise in non-ischemic heart disease are related to a disturbed ventricular relaxation.