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Evaluation of left ventricular systolic and diastolic dysfunction during transient myocardial ischemia produced by
A J Labovitz1, M K Lewen, M Kern
1Department of Internal Medicine, St. Louis University School of Medicine, Missouri.
Insights
Acute myocardial ischemia rapidly impairs left ventricular diastolic function within 15 seconds of coronary occlusion. Systolic function shows significant impairment later, around 30 seconds, impacting heart function during angioplasty.
Area of Science:
- Cardiology
- Echocardiography
- Myocardial Ischemia
Background:
- Acute myocardial ischemia affects both systolic and diastolic left ventricular function.
- Understanding these functional changes and their clinical correlations is crucial.
Purpose of the Study:
- To investigate left ventricular systolic and diastolic dysfunction during acute myocardial ischemia.
- To correlate these functional changes with electrocardiographic (ECG) changes and chest pain during coronary angioplasty.
Main Methods:
- Doppler echocardiography was used to evaluate 32 patients undergoing coronary angioplasty.
- Diastolic function was assessed using various Doppler-derived indexes.
- Systolic function was evaluated by two-dimensional echocardiography and Doppler indexes.
Main Results:
- Significant impairment of all diastolic function indexes was observed within 15 seconds of coronary occlusion.
- Systolic function indexes showed significant impairment approximately 30 seconds after balloon inflation.
- New wall motion abnormalities appeared around 28.8 seconds during occlusion.
Conclusions:
- Left ventricular diastolic function is impaired very early during acute myocardial ischemia.
- Systolic function impairment occurs later than diastolic dysfunction.
- Doppler echocardiography effectively detects functional changes during ischemia.
Abstract:
Acute myocardial ischemia is known to cause impairment of both left ventricular systolic and diastolic function. To further investigate these changes as well as their relation to common clinical variables (electrocardiographic [ECG] changes and chest pain), 32 patients were evaluated with Doppler echocardiography during coronary angioplasty. Doppler indexes of left ventricular diastolic function included the ratios of peak early to late and peak early to mean diastolic velocities as well as the ratios of early to late and first third to total velocity integral (one-third filling fraction). All diastolic indexes showed significant impairment by 15 seconds after coronary occlusion (ratio peak early to late filling velocity: 1.11 versus 0.96, p less than 0.01; ratio peak early to mean filling velocity: 1.9 versus 1.7, p less than 0.01; ratio early to late velocity integral: 1.58 versus 1.25, p less than 0.01; one-third filling fraction: 41.2 versus 37.7, p less than 0.01). Left ventricular systolic function was evaluated during coronary occlusion both qualitatively, as assessed by the appearance of a new wall motion abnormality on two-dimensional echocardiography (mean 28.8 seconds), and quantitatively by measurement of systolic percent area change on the two-dimensional short-axis view as well as the Doppler echocardiographic stroke integral index. Systolic indexes did not show significant change until 30 seconds after balloon inflation (percent area change: 42.8 versus 29.2, p less than 0.01; stroke integral index: 11.04 versus 9.36, p less than 0.01). ECGs were performed at 15 second intervals.(ABSTRACT TRUNCATED AT 250 WORDS)