Effect of Isometric Handgrip Exercise on Diastolic Function in Pediatric Heart Transplant Recipients

Abstract

Pediatric heart transplant recipients (HTR) have reduced exercise tolerance and diastolic dysfunction at rest despite normal ejection fraction. In adult HTR the impaired diastolic function is related to peak exercise tolerance, but this relationship is poorly understood in pediatric HTR. To determine the effects of low‐grade exercise stress on diastolic function in pediatric HTR, we tested the hypothesis that diastolic function would be augmented during isometric handgrip exercise.MethodsSeven pediatric HTRs were studied (mean±SD age: 10±3 yrs; sex: 3F, 4M; time since transplant: 5.4±2.1 yrs; left ventricular mass: 68±19 g/m2; end‐diastolic volume: 42±6 mL; end‐systolic volume: 12±2 mL; ejection fraction: 71±9 %). Pulsed Doppler was used to quantify early (E) and late (A) diastolic inflow velocities, deceleration time and slope. Tissue Doppler imaging of the lateral mitral annulus was used to assess velocity during early diastole (e′) and late diastole (a′). Left ventricular filling pressure responses were estimated using the early diastolic mitral valve inflow velocity/early diastolic lateral wall tissue velocity ratio (E/e′). Resting diastolic assessment was performed followed by 2 min of isometric handgrip exercise at 30% maximal voluntary contraction with diastolic function re‐assessed during the last 30 s of exercise.ResultsHeart rate (92±10 to 105±13 bpm; P=0.01) and mean arterial pressure (73±7 to 90±21 mmHg; P=0.035) increased from rest to exercise. There was no significant change in E/A (2.2±0.8 to 2.2±1.1; P=0.831), deceleration time (0.183±0.031 to 0.173±0.035 s; P=0.529), deceleration slope (613±152 to 619±169 cm/s2; P=0.926), e′/a′ (2.8±0.7 to 2.5±1.2 cm/s2; P=0.433), or E/e′ (7.02±1.37 to 7.13±1.71; P=0.709) from rest to exercise.ConclusionPediatric HTR have diastolic dysfunction at rest that is not augmented during low‐grade handgrip exercise stress.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.