Left Ventricular End-systolic Size Research Articles

Outcomes of Patients With Reduced Exercise Capacity at Time of Exercise Echocardiography

Objective To characterize the prognostic implications of exercise echocardiography in patients who have reduced exercise capacity at the time of testing. Patients and Methods We examined the outcomes of 941 patients at the Mayo Clinic in Rochester, Minn, between January 1, 1990, and December 31, 1995, who had reduced exercise capacity on exercise echocardiography (women, <5 metabolic equivalents; men, <7 metabolic equivalents) and evaluated the potential association between clinical, electrocardiographic, and echocardiographic variables and outcomes for patients with normal vs abnormal exercise echocardiograms. We used variables of independent prognostic value to estimate cardiac risk. Results For patients with normal exercise echocardiograms (n=282), the rate of cardiac death or nonfatal myocardial infarction was 0.9% per person-year of follow-up, and previous coronary revascularization was the only predictor of the time to cardiac event. For patients with abnormal exercise echocardiograms (n=659), the cardiac event rate was 4.4%. Independent predictors of outcome were exercise left ventricular (LV) ejection fraction (risk ratio, 1.44 per 10% decrement; 95% confidence interval, 1.2-1.7; P<.001) and an increase or no change in LV end-systolic size in response to exercise (risk ratio, 2.22; 95% confidence interval, 1.2-4.1; P=.01). Conclusion Exercise echocardiographic findings have important prognostic implications for patients who have reduced exercise capacity on testing. Echocardiographic descriptors of LV systolic function and dysfunction obtained immediately after exercise can be used to stratify cardiac risk of patients who do not achieve a level of exercise ordinarily considered to be of “diagnostic” value. To characterize the prognostic implications of exercise echocardiography in patients who have reduced exercise capacity at the time of testing. We examined the outcomes of 941 patients at the Mayo Clinic in Rochester, Minn, between January 1, 1990, and December 31, 1995, who had reduced exercise capacity on exercise echocardiography (women, <5 metabolic equivalents; men, <7 metabolic equivalents) and evaluated the potential association between clinical, electrocardiographic, and echocardiographic variables and outcomes for patients with normal vs abnormal exercise echocardiograms. We used variables of independent prognostic value to estimate cardiac risk. For patients with normal exercise echocardiograms (n=282), the rate of cardiac death or nonfatal myocardial infarction was 0.9% per person-year of follow-up, and previous coronary revascularization was the only predictor of the time to cardiac event. For patients with abnormal exercise echocardiograms (n=659), the cardiac event rate was 4.4%. Independent predictors of outcome were exercise left ventricular (LV) ejection fraction (risk ratio, 1.44 per 10% decrement; 95% confidence interval, 1.2-1.7; P<.001) and an increase or no change in LV end-systolic size in response to exercise (risk ratio, 2.22; 95% confidence interval, 1.2-4.1; P=.01). Exercise echocardiographic findings have important prognostic implications for patients who have reduced exercise capacity on testing. Echocardiographic descriptors of LV systolic function and dysfunction obtained immediately after exercise can be used to stratify cardiac risk of patients who do not achieve a level of exercise ordinarily considered to be of “diagnostic” value.

Outcomes of Patients With Reduced Exercise Capacity at Time of Exercise Echocardiography

To characterize the prognostic implications of exercise echocardiography in patients who have reduced exercise capacity at the time of testing. We examined the outcomes of 941 patients at the Mayo Clinic in Rochester, Minn, between January 1, 1990, and December 31, 1995, who had reduced exercise capacity on exercise echocardiography (women, <5 metabolic equivalents; men, <7 metabolic equivalents) and evaluated the potential association between clinical, electrocardiographic, and echocardiographic variables and outcomes for patients with normal vs abnormal exercise echocardiograms. We used variables of independent prognostic value to estimate cardiac risk. For patients with normal exercise echocardiograms (n=282), the rate of cardiac death or nonfatal myocardial infarction was 09% per person-year of follow-up, and previous coronary revascularization was the only predictor of the time to cardiac event. For patients with abnormal exercise echocardiograms (n=659), the cardiac event rate was 4.4%. Independent predictors of outcome were exercise left ventricular (LV) ejection fraction (risk ratio, 1.44 per 10% decrement; 95% confidence interval, 1.2-1.7; P<.001) and an increase or no change in LV end-systolic size in response to exercise (risk ratio, 2.22; 95% confidence interval, 1.2-4.1; P=.01). Exercise echocardiographic findings have important prognostic implications for patients who have reduced exercise capacity on testing. Echocardiographic descriptors of LV systolic function and dysfunction obtained immediately after exercise can be used to stratify cardiac risk of patients who do not achieve a level of exercise ordinarily considered to be of "diagnostic" value.

Outcome after abnormal exercise echocardiography for patients with good exercise capacity: Prognostic importance of the extent and severity of exercise-related left ventricular dysfunction

ObjectivesWe sought to define the prognostic implications of the extent and severity of exercise echocardiographic abnormalities in patients with good exercise capacity. BackgroundThe exercise capacity of patients with known or suspected coronary artery disease (CAD) is of prognostic importance, as is the extent of exercise-related left ventricular (LV) hypoperfusion or dysfunction. MethodsWe examined the outcomes of 1,874 patients with known or suspected CAD (mean age 64 ± 10 years, 64% men) who had good exercise capacity (≥5 metabolic equivalents [METs] for women, ≥7 METs for men) but abnormal exercise echocardiograms and analyzed the potential association between clinical, exercise and echocardiographic variables and subsequent cardiac events. ResultsMultivariate predictors of time to cardiac death or nonfatal myocardial infarction (MI) were diabetes mellitus (risk ratio [RR] 1.88; 95% confidence interval [CI] 1.2 to 3.0), history of MI (RR 2.44; 95% CI 1.6 to 3.6) and an increase or no change in LV end-systolic size in response to exercise (RR 1.61; 95% CI 1.1 to 2.5). Using echocardiographic variables that were of incremental prognostic value, we were able to stratify the cardiac risk of the study population; cardiac death or nonfatal MI rate per person-year of follow-up was 1.6% for patients who had a decrease in LV end-systolic size in response to exercise (n = 1,330) and 1.2% for patients who did not have any severely abnormal LV segments immediately after exercise (n = 868). ConclusionsIn patients with good exercise capacity, echocardiographic descriptors of the extent and severity of exercise-related LV dysfunction were of independent and incremental prognostic value. Stratification of patients into low- and higher risk subgroups was possible using these exercise echocardiographic characteristics.

A canine model of chronic ischemic cardiomyopathy: characterization of regional flow-function relations.

The controversy regarding the mechanism(s) of left ventricular (LV) dysfunction in chronic coronary artery disease is, in part, related to the lack of an appropriate animal model for this condition. We have developed such a model by placing Ameroid constrictors on proximal portions of coronary arteries in dogs who were euthanized (mean of 6 wk) after the development of severe global LV dysfunction noted on two-dimensional echocardiography. The LV end-systolic size nearly doubled (P < 0.001) over the observation period, and the percent change in LV size from end diastole to end systole decreased by >50% (P < 0.001). Regional dysfunction was noted in 23 of 24 myocardial beds analyzed within regions showing no gross evidence of infarction. In 10 of these beds, severe dysfunction was noted without a decrease in radiolabeled microsphere-derived myocardial blood flow (MBF). In 13 myocardial beds, decrease in function was associated with a decrease in MBF (P < 0.001), with close coupling noted between percent wall thickening and MBF. In the beds that exhibited an ultimate decrease in MBF, the decrease in function preceded the decrease in MBF. In conclusion, we describe chronic LV dysfunction in a canine model of multivessel stenosis that closely mimics chronic ischemic LV dysfunction in humans. Whereas regional function is severely reduced in this model, MBF is varied in different segments and at different times during the observation period. These results provide new insights regarding flow-function relations in chronic ischemic LV dysfunction.

The influence of heart rate on echocardiographic assessment of aerobic training.

AbstractThe purpose of this investigation was to determine if echocardiographic measures of ventricular structure and function ascribed to aerobic training might be an artifact of heart rate (HR) differences between trained and untrained subjects. Comparisons were made at rest, of 10 young, male, aerobically well‐trained athletes [((VO2)max 65&gt;ml/kg/min] and 10 young, healthy controls [((VO2)max&lt;56ml/kg/min]. Additionally, the echocardiographic responses to low (HR=80 beats/min) and moderate intensity (HR=120 beats/min) supine cycling exercise were analyzed. Echocardiographic measures were made as described by Sahnet al. (1978). Results of echocardiographic comparisons between groups, both during supine rest and at a constant heart rate of 80 beats/min during supine cycling confirmed that athletes had significantly greater left ventricular mass (LV mass) and end‐diastolic size per square meter of body surface area (p&lt;0.05). When supine cycling loads were increased to elevate HR to 120 beats/min in groups of 7 athletes and 5 controls, athletes exhibited a progressive and significant (p&lt;0.05) enlargement of left ventricular end‐diastolic size (LVEDS), while left ventricular end‐systolic size (LVESS) showed negligible change. The control group showed little change in LVEDS, but decreased LVESS significantly (p&lt;0.05). Contractility measures, i.e., estimated ejection fraction (EF) and velocity of circumferential shortening ( (Vcf) increased in both groups in a similar manner. It was concluded that echocardiographic differences in ventricular structure and function observed between aerobically trained and untrained subjects are not an artifact of heart rate differences. Clearly, aerobic training results in increased LV mass and diastolic size which allows for further dilitation with supine exercise. Aerobic training does not appear to alter indices of myocardial contractility.