Echocardiography in selecting pediatric and congenital heart disease patients for resynchronization therapy: a 4 years follow up study

Abstract

Background: There are no widely accepted selection criteria for cardiac resynchronization therapy (CRT) in the pediatric and congenital heart disease (CHD) population. Data on mechanical dyssynchrony as assessed by echocardiography and its predictive power are lacking. Aim: To assess in a long term follow up study the predictive value of echocardiographic dyssynchrony parameters in CHD and pediatric patients who underwent CRT. Methods: We studied 20 pediatric and CHD patients (median age 5.6 years, range 0.6- 39.8 years, all but one < 16 years) who received CRT at our Institution from 2002 to 2010. Echocardiographic dyssynchrony parameters were assessed on baseline echocardiographic examination, before CRT implantion, and their prognostic ability was assessed over a 4 year (range 1 – 7 years) follow up period. Patients were classified as responders if at the last visit their global systolic function assessed by ejection fraction (EF) or by fractional area change, increased ≥ 10%. Results: There were 12 (60%) responders and 8 (40%) non responders to CRT. None of the studied patients died during follow-up. The 2 groups were similar for EF, QRS and NYHA class, before CRT. Studied indexes of interventricular, longitudinal and radial intraventricular dyssynchrony before CRT were comparable. Only the presence of septal flash before CRT was significantly (p=0.0363) more frequent in responders (11/12, 91.7%) than in non responders (3/8, 37.5%), (sensitivity of 91.7%, specificity of 62.5%, accuracy of 80.2%). Conclusions: This is the largest and the longest follow-up study on CRT in pediatric and congenital heart disease patients. This study demonstates 3 major findings. First, mechanical dyssynchrony manifested by SF is a good predictor of response to CRT in pediatric and CHD patients. Second, electrical dyssynchrony is not an important contributor to mechanical dyssynchrony in children and CHD patients. Third, the survival over a median follow up period of 4 years in our cohort is excellent.