Right Ventricular Contractile Reserve Is Impaired in Children and Adolescents With Repaired Tetralogy of Fallot: An Exercise Strain Imaging Study

Abstract

Background: Pulmonary insufficiency (PI) and right ventricular (RV) dysfunction are long-term complications in rTOF. We sought to investigate RV contractile reserve and changes in PI that occur during exercise in patients with repaired tetralogy of Fallot (rTOF) and the association of these changes with exercise performance using stress echocardiography. Methods: Subjects with rTOF (n = 32) and healthy controls (n=10) were prospectively enrolled and underwent rest and peak exercise echocardiograms during standard CPET protocol on cycle ergometer or treadmill. RV contractile reserve was defined as the change in RV global longitudinal strain (RVGLS) from rest to peak exercise. PI was assessed with the diastolic systolic time velocity integral ratio (DSTVI) and diastolic/systolic velocity ratio (D/S Ratio) from pulmonary artery Doppler interrogation. Exercise measures included heart rate reserve, percent-predicted maximum oxygen consumption (%mVO2), percent-predicted maximum work (%mWork) and oxygen pulse. Results: Right ventricular contractile reserve was impaired in rTOF compared to controls with a significant drop in the absolute value of RVGLS from 17% (range 8-27) at rest to 13% (range 5-28) at peak exercise. Similarly, PI decreased at peak exercise, with a drop in DSTVI and D/S ratios. Reduction in PI was directly associated with %mVO2, %mWork, and greater oxygen pulse. Heart rate reserve was directly associated with %mVO2 and %mWork. RV contractile reserve was not associated with any exercise parameters. Conclusions: Patients with rTOF have an abnormal myocardial response to exercise with impaired RV contractile reserve compared to control subjects. Heart rate reserve and reduction in PI at peak exercise are associated with better exercise performance and appear to be significant contributors to exercise performance in rTOF. Measures to improve chronotropic health in rTOF should be explored.

Echocardiographic assessment of the tricuspid and pulmonary valves: a practical guideline from the British Society of Echocardiography

“…Normal resting RV longitudinal function may therefore be falsely reassuring in the context of RV dilatation. Other studies have utilised a variety of exercise measurements, including TAPSE, RV fractional area change, and RV longitudinal strain, to demonstrate impaired RV functional reserve in tetralogy of Fallot repair patients with residual PR ( 55 , 56 ). Further studies such as these are needed to help refine surgical criteria, by identifying patients that will benefit from earlier intervention due to occult RV dysfunction seen only during stress, or conversely those with irreversible RV damage in whom operative risk might outweigh any potential gains.…”

Right ventricular strain rate during exercise accurately identifies male athletes with right ventricular arrhythmias

“…Previous studies assessing RV functional reserve have predominantly looked at the relative change in peak strain from rest-to-exercise. 24,25 Vitarelli et al identified ΔSL as the most accurate parameter to identify subjects with ARVC. 12 However, in these studies cardiac function was already impaired in the rested state, as opposed to our cohort in which RV function was ostensibly normal at rest.…”

Echocardiographic strain analysis reflects impaired ventricular function in youth with pediatric‐onset systemic lupus erythematosus

“…While LS A4C and CS mid are more limited components of strain, published pediatric reference values for calculation of standard deviation scores (SDS) by body surface area (BSA) are available, 24 and there are also data to suggest they are good approximations of global measures based on averages of three views 25 . Strain measurements were analyzed offline using Image Arena Version 4.6 (TomTec Imaging Systems) by an experienced research sonographer (YW) with proven intra‐observer reliability 26,27 …”

“…with proven intra-observer reliability. 26,27 Standard measures of LV systolic function were assessed, including ejection fraction (LVEF) and shortening fraction (LVSF). We also assessed measures of LV diastolic function, including mitral E/A ratio (peak early over peak late diastolic filling velocity), septal and lateral e′ (early diastolic mitral annular tissue velocity), E/e′ ratio (peak early diastolic filling velocity over early diastolic mitral annular tissue velocity), isovolumetric relaxation time (IVRT), deceleration time (DT), and left atrial volume index (LAVI).…”