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Left ventricular performance in coronary artery disease evaluated with systolic time intervals and echocardiography
Insights
Noninvasive systolic time intervals and echocardiographic measures effectively detect left ventricular dysfunction after myocardial infarction. These methods, particularly the pre-ejection period to left ventricular ejection time ratio (PEP/LVET) and percent change in minor axis diameter (%delta D), are more sensitive than clinical assessments.
Area of Science:
- Cardiology
- Diagnostic Imaging
- Noninvasive Cardiovascular Assessment
Background:
- Evaluating left ventricular (LV) performance post-myocardial infarction (MI) is crucial for patient management.
- Traditional clinical bedside methods may not reliably detect subtle LV dysfunction.
- Systolic time intervals (STIs) and echocardiography offer noninvasive approaches to assess cardiac function.
Purpose of the Study:
- To simultaneously assess LV performance using STIs and echocardiography in normal subjects and post-MI patients.
- To determine the sensitivity of these noninvasive measures in detecting LV dysfunction.
- To compare the efficacy of noninvasive methods with clinical indicators and chest roentgenograms.
Main Methods:
- Simultaneous measurement of STIs (PEPI, LVETI, PEP/LVET) and echocardiographic parameters (%delta D, Vcf, Dd) in 25 normal subjects and 37 post-MI patients.
- Correlation analysis between STIs, echocardiographic measures, and clinical parameters (dyspnea, fatigability, angina).
- Assessment of coronary artery obstruction via coronary arteriography in a subset of patients.
Main Results:
- Post-MI patients showed significant differences in all measured noninvasive parameters compared to controls (P < 0.001).
- PEP/LVET and %delta D were the most sensitive indicators of LV dysfunction, detecting abnormalities in 70-85% of patients without significant symptoms.
- Noninvasive measures correlated strongly with dyspnea and fatigability, and with the extent of coronary artery disease (2-3 vessel involvement).
Conclusions:
- Noninvasive STIs and echocardiographic measures are highly sensitive in evaluating LV performance after MI.
- PEP/LVET and %delta D demonstrate superior sensitivity compared to clinical bedside methods and chest roentgenograms.
- These noninvasive techniques provide valuable objective data for assessing LV dysfunction in post-MI patients.
Abstract:
Simultaneous determinations of systolic time intervals (preejection period index [PEPI], left ventricular ejection time index [LVETI] and ratio of preejection period to left ventricular ejection time [PEP/LVET]) and echographic measures of left ventricular performance (percent change in minor axis diameter [%delta D], circumferential shortening rate [Vcf] and end-diastolic diameter [Dd]) were obtained in 25 normal subjects and 37 patients with previously documented transmural myocardial infarction. The group with previous infarction demonstrated significant (P less than 0.001) differences from the normal group in each of the noninvasive measures. PEP/LVET and %deltaD were the most sensitive measures of left ventricular dysfunction. Deviation from the normal range in these measures occurred, respectively, in 70 and 65 percent of patients without dyspnea or fatigability (20 patients) and 85 percent of those without angina pectoris (13 patients). Abnormalities in systolic time interval and echocardiographic measures were related to the severity of dyspnea and fatigability but not to that of angina. Neither the presence of phonocardiographically documented third or fourth sound gallops nor an abnormal cardiothoracic ratio by chest roentgenogram reliably detected patients with abnormal left ventricular performance. The range of abnormality in left ventricular performance did not differ between patients with prior anterior or diaphragmatic myocardial infarction. The frequency of abnormal performance was greatest among patients with combined sites of prior infarction. Among 26 patients studied by coronary arteriography, abnormal left ventricular performance as determined by values for PEP/LVET and %deltaD occurred in fewer than 30 percent of those with 70 percent or greater obstruction of one coronary artery and in more than 80 percent of those with two or three vessel involvement. There was a high correlation between systolic time intervals, %delta D and Vcf, the closest correlation occurring between PEP/LVET and %deltaD (r = -0.93). These data document the sensitivity of the noninvasive systolic time intervals and echographic measures and their superiority over current clinical bedside methods in evaluating left ventricular performance in patients with prior myocardial infarction.