Abstract 14103: Left Ventricular Systolic Longitudinal Function Reserve Determines Exercise Capacity

Abstract

Background: Despite of evidence between left ventricular (LV) diastolic dysfunction and exercise capacity in subclinical patients, the relation of systolic LV longitudinal function with exercise capacity has not been well studied.

Objective: To investigate relations between LV systolic longitudinal function reserve during exercise and exercise capacity in subclinical patients with hypertension.

Methods: Twenty patients with hypertension (HT group; LVEF 60±9%, 72±6 years) and 21 normal subjects (control group; LVEF 64±5%, 57±13 years) were enrolled. First, a symptom-limited ramp exercise test using a supine cycle-ergometer was performed to measure peak oxygen uptake (peakVO2). Second, exercise stress echocardiographic examinations were repeated at baseline and peak exercise level that determined by peakVO2. Systolic longitudinal function was assessed by systolic global longitudinal strain (GLS) and peak GLS rate (GLSRs) with 2D speckle tracking imaging. Diastolic longitudinal function was assessed by early diastolic GLSR (GLSRe), and mitral annular velocity (E’) with tissue Doppler imaging. The change ([[Unable to Display Character: ▵]]) of echocardiographic parameters between baseline and at peak exercise was calculated in assessing LV longitudinal function reserve.

Results: PeakVO2 was significantly lower in HT group compared to control group (20±5 vs. 26±4 mL/kg/min, P<0.01). At baseline, E’ alone differed between groups (11±2 vs. 8±2, P<0.01). GLS and GLSRs at exercise (GLS, -14.6±3.7 vs. -17.1±2.9 %, P=0.05; GLSRs, -1.03±0.3 vs. -1.26±0.2 1/sec, P=0.02) in HT group were significantly lower than those of control group. In addition, [[Unable to Display Character: ▵]]GLSRs (-0.39±0.2 vs. -0.61±0.2 1/sec, P=0.01) and [[Unable to Display Character: ▵]]E’ (3.9±3.9 vs. 6.7±3.0, P=0.03 cm/sec) were significantly lower than those of control group. Multiple stepwise regression analysis revealed that [[Unable to Display Character: ▵]]E’ and [[Unable to Display Character: ▵]]GLSRs were selected as significant variables to determine peakVO2.

Conclusion: LV systolic longitudinal function reserve was one of the critical determinants of exercise capacity. Consequently, stress echocardiography with longitudinal functional analysis may provide additional information in assessing lower exercise capacity in subclinical hypertension patients.