Abstract 13069: Resting and Exercise Lusitropy Predicts Exercise Capacity in Patients with Normal Left Ventricular Systolic Function

Abstract

Background: The diastolic echo stress test may identify contributing factors to exercise capacity limitation. We sought to identify diastolic predictors of exercise capacity in patients with preserved LV systolic function.

Methods: We examined echocardiographic measures in 214 consecutive patients (mean age 56 ± 3 years, 51% female) with LV ejection fraction ≥50% referred for standard treadmill stress echocardiography using the Bruce protocol. Subjects with congestive heart failure, significant valvular disease, and inducible ischemia were excluded. Variables measured at baseline and immediately following symptom limited exercise were pulsed-wave Doppler of E/A mitral inflow velocities, medial and lateral mitral annular and tricuspid annular tissue Doppler s’ and e’ velocities (in 4-chamber view), LV E/e’ ratio, pulmonary vein S/D velocities, and peak TR regurgitant velocity. We performed age- and gender-adjusted regression analyses.

Results: Peak exercise time and exercise capacity for the entire group were 8.6 ± 2.4 minutes, and 8.6 ± 3.2 METS (range 2.4 -17.3 METS), respectively. For the entire group, distribution of diastolic function categories were 28% normal, 41% grade 1, 18% grade 2, 2% grade 3 dysfunction, and 11% indeterminate. RV systolic pressure measured by TR velocity was 23 ± 7 mmHg at rest and increased to 35 ± 11 mmHg at peak exercise (p<0.001). Both age and gender were significantly associated with exercise capacity with a model R-square value of 0.34 (p<0.001) but without an effect interaction on METS (p=0.73). When adjusted for age and gender, only resting and peak-exercise lateral mitral annular e’ velocity (both R-square 0.4, p < 0.05) and peak-exercise estimated RV systolic pressure (R square of 0.4, p = 0.02) correlated significantly with exercise capacity (METS). Specifically, resting diastolic function grades and E/e’ did not predict exercise capacity.

Conclusion: In an unselected population referred for treadmill stress echo testing, measures of LV lusitropy and RV systolic pressure were significantly associated with reduced exercise tolerance in patients with preserved left ventricular systolic function.