Prognostic value of cardiopulmonary exercise testing in children with heart failure secondary to idiopathic dilated cardiomyopathy in a non-beta-blocker therapy setting.
BACKGROUND
Peak oxygen consumption and resting left ventricular ejection fraction (LVEF) are independent predictors of survival in adult heart failure (HF) patients.


OBJECTIVE
To evaluate these factors in children.


METHODS
We prospectively studied 31 children with NYHA class I to III HF (mean LVEF 26+/-10%; mean age 8.6+/-1.9 years). All had dilated cardiomyopathy and were awaiting heart transplantation. A cardiopulmonary treadmill exercise test was performed and LVEF determined by radionuclide ventriculography.


RESULTS
During a median follow-up of 1282 days, 20 children reached at least one end-point (death or heart transplantation). Clinical data from the 11 children without events and the 20 children with events are as follows: NYHA class 1+/-0 vs. 2+/-0.9 (p<0.01); SBP 118+/-17 vs. 102+/-16 (p=0.01); DBP 70+/-10 vs. 61+/-10 (p=0.02); heart rate 165+/-22 vs. 148+/-22 (NS); double-product 19+/-4 vs. 15+/-4 (p=0.01); end-tidal carbon dioxide tension (PetCO2) 35+/-5 vs. 30+/-6 (NS); oxygen consumption (VO2) 22+/-5.4 vs. 18.3+/-5.7 (NS); exercise time 19+/-4 vs. 13+/-6 (p<0.003), and LVEF 31+/-8 vs. 22+/-10 (p=0.02). These variables all correlated with prognosis on univariate analysis. In multivariate analysis, only decreasing exercise time and LVEF were predictive of events during follow-up (p<0.001 and 0.04).


CONCLUSIONS
These findings suggest that reduction in LVEF and exercise tolerance in children with heart failure is predictive of functional status.
Guimarães
Guilherme Veiga
GV
InCor - Instituto do Coração - HC/FMUSP, São Paulo, Brazil. gvguima@usp.br <gvguima@usp.br>
d'Avila
Veridiana Moraes
VM
Camargo
Paulo Roberto
PR
Moreira
Luiz Felipe Pinho
LF
Lanz
Jose Ramon
JR
Luces
Jose Ramon Lanz
JR
Bocchi
Edimar Alcides
EA
D002311:Cardiomyopathy, Dilated / Q000150:complications* / Q000401:mortality / Q000503:physiopathology; D002648:Child; D015331:Cohort Studies; D018572:Disease-Free Survival; D005080:Exercise Test; D017079:Exercise Tolerance / Q000502:physiology*; D005260:Female; D006333:Heart Failure / Q000209:etiology / Q000401:mortality* / Q000503:physiopathology*; D016027:Heart Transplantation; D006801:Humans; D008297:Male; D011237:Predictive Value of Tests; D012146:Rest / Q000502:physiology; D013318:Stroke Volume / Q000502:physiology*; D015996:Survival Rate