The Assessment of Left Ventricular Function in Patients with and without Left Ventricular Systolic Dysfunction by the Resting Versus Peak Exercise Left Ventricular Ejection Fraction-An Observational Study

Abstract Background: Ejection fraction (EF) is widely used as a measure of systolic function. However, it doesn’t correlate well with exercise tolerance and other measures of peak cardiac output. Present study was conducted to compare resting ejection fraction and peak exercise left ventricular ejection fraction as a measure of left ventricular function and correlate it with peak exercise capacity, symptom class and morbidity index in patients with and without left ventricular systolic dysfunction. Material and Methods: Baseline and peak exercise LV dimensions, stroke volume and cardiac output were measured in patients who were referred for stress echocardiography (treadmill or dobutamine stress testing). We analysed the relationship between exercise capacity, symptom class, morbidity index and LVH with change in LV dimensions during rest and exercise. In addition, we also analysed the change in LV dimensions in young adults, elderly hypertensives and patients of ischemic or dilated cardiomyopathy with exercise. Results: Exercise time and the maximal achieved workload were similar between elderly hypertensives and low resting EF patients (total exercise time ≈ 6 and half minutes and MWL≈ 8 METS in both the groups) but were significantly impaired in patient groups compared with young adults (total exercise time ≈ 10 minutes and MWL≈ 11 METS). At peak exercise, young adults and patients with HFrEF (Low EF) showed no change in LVedD, but there was a significant decrease in peak exercise LVedD (43.33 mm to 39.04 mm) in patients with HFpEF. Stroke volume increased in healthy adults (from 60.95 ml to 74.11 ml) and patients with HFrEF (from 53.55 ml to 60.20 ml) but showed no change in patients with HFpEF (52.25 ml at rest, 51.75 ml at peak exercise). Increase in peak exercise cardiac output was 2.9-fold in healthy adults, 2.5-fold in HFrEF, and 2.1-fold in elderly hypertensives. Conclusion: Resting ejection fraction in young patients with past infarctions reflects increased end-diastolic volume with normal resting stroke volume; it is not due to systolic dysfunction. Elderly hypertensive patients fail to grow their ventricle by eccentric hypertrophy and they have systolic dysfunction, with impaired contractile reserve and little augmentation of systolic ejection during stress and severe worsening of abnormalities of relaxation during stress, with decrease in ventricular end-diastolic dimension, unlike healthy individuals and young patients with low EF. Therefore, normal resting echocardiography does not preclude the presence of significant functional abnormalities on exercise that can contribute to symptoms in patients with HFpEF. LVEF is a flawed measure of contractility and normal resting LVEF does not imply normal LV systolic function.