Changes in left ventricular diastolic function during exercise in patients with coronary artery disease
U Tebbe1, K H Scholz, H Kreuzer
1Department of Cardiology, University of Goettingen, F.R.G.
Insights
Coronary artery disease (CAD) patients show significant changes in left ventricular diastolic pressure-volume relationships during exercise, even without angina or ECG changes. These findings highlight exercise-induced diastolic dysfunction in CAD.
Area of Science:
- Cardiology
- Cardiovascular Physiology
- Biomedical Engineering
Background:
- Coronary artery disease (CAD) can affect left ventricular (LV) diastolic function.
- Understanding exercise-induced changes in diastolic pressure-volume (P-V) relationships is crucial for assessing cardiac performance in CAD patients.
Purpose of the Study:
- To investigate alterations in LV diastolic P-V relationships during exercise in patients with CAD compared to controls.
- To correlate these diastolic changes with the presence of angina, exercise electrocardiogram (ECG) findings, and underlying mechanisms.
Main Methods:
- Obtained biplane ventriculograms and high-fidelity pressure measurements at rest and during bicycle exercise in 10 controls and 43 CAD patients.
- Quantified shifts in diastolic P-V relationships using constants 'a' and 'b' from the linear log P-V relationship.
- Analyzed the contribution of the Frank-Starling mechanism, diastolic compliance, and pericardial pressure during exercise.
Main Results:
- In CAD patients, exercise caused a significant decrease in constant 'a' and a significant increase in constant 'b' of the diastolic P-V relationship, unlike controls.
- Diastolic P-V shifts occurred during exercise even in the absence of angina or ECG signs of ischemia.
- Exercise-induced diastolic alterations correlated with exercise ECG findings.
Conclusions:
- Exercise significantly alters the diastolic P-V relationship in patients with CAD, indicating diastolic dysfunction.
- These diastolic changes can occur independently of angina or ECG evidence of ischemia, suggesting a sensitive marker for subclinical dysfunction.
- Further analysis is needed to fully elucidate the interplay of Frank-Starling, compliance, and pericardial factors in exercise-induced diastolic pressure changes in CAD.
Abstract:
In 10 controls and 43 patients with coronary artery disease (CAD) left ventricular (LV) diastolic pressure-volume (P-V) curves were obtained from biplane ventriculograms and simultaneous high fidelity pressure measurement at rest and during bicycle exercise. During exercise ventriculography 20 patients had angina pectoris, and 16 patients were asymptomatic. At rest there were no akinetic segments in 28 patients, and at least one akinetic segment was found in 15 patients. Shifts in the diastolic P-V relationship with exercise were quantitated from the constants a and b of the linear log P-V relationship. In the control group a and b did not change significantly, but in all CAD groups a significant decrease in a and a significant increase in b were observed during exercise. While no patient with angina had an unchanged diastolic P-V relationship, as many as 12 patients had significant P-V shifts in the absence of angina. A similar correlation was found for the diastolic P-V alterations and the exercise ECG. Fourteen patients without any ST-segment change during exercise showed significant P-V shifts, while no patient with signs of ischaemia in the ECG had an unchanged P-V curve. In another 20 patients with CAD the relative contribution of the Frank-Starling mechanism, diastolic compliance and the pericardium to the filling pressure rise during exercise was analyzed. Left ventricular and right atrial pressures--as an index of pericardial pressure--were measured simultaneously during rest and exercise ventriculogram. This was done when filling pressures exceeded 30 mmHg or when angina pectoris occurred.(ABSTRACT TRUNCATED AT 250 WORDS)
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