Abstract 14036: Impaired Diastolic Reserve During Exercise in Children After Anthracycline Therapy With Normal Left Ventricular Ejection Fraction
Background Anthracycline cardiotoxicity is a late complication of chemotherapy for childhood cancer and has an impact on exercise performance. We evaluated left ventricular systolic and diastolic function in children after anthracycline chemotherapy with preserved left ventricular ejection fraction during exercise using two-dimensional echocardiography and speckle tracking imaging, to explore the determinants of exercise impairment.
Methods Ten patients (median age 15 yrs, range 8 -19 yrs, 6 male) performed incremental cycle exercise testing to measure peak aerobic power (peak VO2). Echocardiography of the basal short axis was performed at 3 stages: 1) resting baseline (supine), 2) sitting on cycle ergometer, and 3) peak exercise. End diastolic cavity area (EDCA), end systolic cavity area (ESCA) and fractional area change (FAC) as well as circumferential strain and strain rate (SR) were measured. Data (median, [range]) was compared between stages using Wilcoxon matched-pairs signed rank test (p<0.05).
Results The median time from chemotherapy was 6 years, [2 to 16]. Systolic SR increased from supine to sitting (-1.26 s-1 [-1.58 to -0.9] vs. -1.43 s-1 [-1.83 to -0.8]; p<0.05), and from sitting to exercise (-1.43 s-1 [-1.83 to -0.8] vs. -2.42 s-1 [-3.47 to -1.98]; p<0.01). Both EDCA and ESCA decreased from supine to sitting (EDCA: 17 cm2 [10 to 23] vs. 10.7 cm2 [7 to 20]; p<0.01, ESCA 8.2 cm2 [4.5 to12.3] vs. 5.4 cm2 [4 to 11]; p<0.01). FAC increased from sitting to peak exercise (48% [37 to 55] vs. 59% [45 to 72]; p<0.01) due to a decrease in ESCA (5.4 cm2 [4.1 to 11.1] vs. 4.4 cm2 [3.2 to 9.0]; p<0.05) and no change in EDCA (10.7 cm2 [7 to 20] vs. 10.8 cm2 [6.4 to 24.4]; p=0.43). No change in strain occurred between stages. Peak VO2 ranged from 28.1 to 60.2 (median 42.5) ml/kg/min and is 12% lower than healthy age matched predictions. No echocardiography parameters correlated with peak VO2.
Conclusion Children after anthracycline had impaired exercise tolerance. Ventricular FAC and SR increased appropriately with peak exercise, consistent with preserved systolic function. Failure to increase EDCA from sitting to peak exercise suggests reduced diastolic reserve and may contribute to impaired exercise performance.
- © 2011 by American Heart Association, Inc.