Determinants of Exercise Performance in Children and Adolescents with Repaired Tetralogy of Fallot Using Stress Echocardiography

Abstract

Exercise performance is variable and often impaired in patients with repaired tetralogy of Fallot (rTOF). We sought to identify factors associated with exercise performance by comparing high to low performers on cardiopulmonary exercise testing (CPET) in patients with rTOF. We conducted a cross-sectional study of subjects presenting for CPET who underwent echocardiograms at rest and peak exercise. Patients with pacemakers and arrhythmias were excluded. Right ventricular (RV) global longitudinal strain was used as a measure of systolic function. Pulmonary insufficiency (PI) was assessed with the diastolic systolic ratio and the diastolic systolic time-velocity integral ratio by Doppler interrogation of the pulmonary artery. CPET measures included percent-predicted maximum [Formula: see text] [Formula: see text], percent-predicted maximum work and oxygen pulse. High versus low performers were identified as those achieving [Formula: see text] of at least 80% or falling below, respectively. Differences in echocardiographic parameters from rest to peak exercise were examined using mixed-effects regression models. Compared to the low performers (n = 17), high performers (n = 12) were younger (12.8 ± 3.3 years vs. 18.3 ± 4.8 years), had normal chronotropic response (peak heart rate > 185 bpm) with greater heart rate reserve and superior physical working capacity. High performers also had a greater reduction in PI at peak exercise, despite greater PI severity at rest. Oxygen pulse was comparable between groups. For both groups, there was no association of PI severity and RV systolic function at rest with exercise parameters. There was no group difference in the magnitude of change in RV strain and diastolic parameters from rest to peak exercise. Chronotropic response to exercise appears to be an important parameter with which to assess exercise performance in rTOF. Chronotropic health should be taken into consideration in this population, particularly given that RV function and PI severity at rest were not associated with exercise performance.

Systolic and diastolic functional reserve of the subpulmonary and systemic right ventricles as assessed by pharmacologic and exercise stress: A systematic review

“…Of the 913 records initially identified, 56 23–78 studies with a total of 1730 patients were included in the qualitative synthesis (Figure 1). Of these 56 studies, 23 23–45 studied subpulmonary RV reserve in patients with repaired TOF, 19 46–64 assessed systemic RV reserve, and 14 65–78 assessed subpulmonary RV reserve with or without RV‐pulmonary arterial coupling in patients with PAH.…”

“…Pharmacologic stress with continuous infusion of incremental dose of dobutamine was employed in 22 studies 23–33,46–52,65–68 . On the other hand, exercise stress with either bicycle 34–45,53–64,69–76 or treadmill exercise testing 77,78 was used in 34 studies.…”

“…The following echocardiographic parameters had been used to assess RV functional reserve: (i) 2‐dimensional echocardiography based‐parameters including RV fractional area change (FAC), ejection fraction (EF), and stroke volume (SV), 23,24,36,55,67,70,71,77 (ii) M‐mode derived ventricular diameters, 55 tricuspid annular peak systolic excursion (TAPSE) 36–38,40,46,55,65–67,70,71,77 and fractional shortening of the RV outflow tract, 37 (iii) conventional Doppler‐derived RV dP/dt, 24,34,35 RV systolic pressure, 34–36 and myocardial performance index, 71 (iv) tissue Doppler‐derived tricuspid annular isovolumic acceleration (IVA) 37 and peak systolic ( s ), early ( e ) and late ( a ) diastolic myocardial velocities, 24,25,34,35,37,39,40,46,47,53,55,65,66,71,77 and (v) speckle tracking‐derived RV strain 39,40,53,55 and strain rates 53 . Cardiac magnetic resonance was used to measure RV volumes, 26–28,30,31,41,43,48–52,54,56,58,59,68,72 FAC, 42 EF, 27,30–33,41,43,48–52,56,59,68,72 cardiac index, 27,29,42,49,51,58,68 wall thickening and motion, 57 and RNA had been used to quantify RV EF 60–64,78 .…”

“…Twenty‐three studies, 23–45 which included 712 patients with repaired TOF, assessed RV functional reserve during stress (Table 1). The mean age of patients ranged from 11 to 34 years.…”

Stress Echo 2030: The Novel ABCDE-(FGLPR) Protocol to Define the Future of Imaging

“…Recently, a few studies have suggested that physical or pharmacological stress may unmask abnormalities of right ventricular function in patients with repaired Tetralogy of Fallot, with normal right ventricular function under resting conditions [86,87]. SE allows the simultaneous assessment of right and left ventricular global and regional function and Doppler parameters as well as coronary flow reserve in posterior descending coronary artery and chronotropic reserve [88] can be impaired in these patients and are potential determinant of exercise capacity [89].…”