587 Cardiac function in children exposed to chemotherapy during intra-uterine life

Introduction: Mid-term effects of cardiac resynchronization therapy (CRT) in congenital heart disease (CHD) have so far rarely been demonstrated. Methods: CRT was applied in 15 pts aged 2.6 -29.2 (median 12.2) yrs with CHD, systemic left (N=7) or right (N=8) ventricular dysfunction and spontaneous (N=4) or pacing induced (N=I 1, mean pacing duration 5.83.3 yrs) ventricular desynchronization using thoracotomy (N=8), transvenous (N=I) or mixed (N=6) lead systems. Concurrent cardiac surgery was performed in 6/15 pts. Follow-up ranged from 1.1-32.4 (mean 16.7) months. Results: There were no major procedure related complications or death. CRT was associated with following acute changes: QRS duration decreased from 16122 to 11517 ms (p<0.001) and interventricular mechanical delay from median 60 to 33 ms (p=0.002). Systemic ventricular max. +dP/dt increased from median 514 to 715 mmHg/s (p=0.002) and aortic velocity-time integral from mean 16.17.3 to 16.87.6 cm (p=0.047). At the end of follow-up Z-score of systemic ventricular enddiastolic dimension (indexed to a normal left ventricle) decreased from median +2.6 to +0.8 (p=0.002). Changes in Z-score tended to be smaller for systemic right (-0.8) than left (-2.0) ventricle (p=0.072). Ejection fraction or fractional area of change increased from mean 2012 to 3712% (p<0.001) and Tei index decreased from mean 0.740.29 to 0.440.21 (p=0.001). Acute and chronic response to CRT was not significantly different between pts with and without concurrent cardiac surgery for any variable. Conclusion: CRT is associated with positive acute hemodynamic changes and significant reverse systemic (left or right) ventricular remodeling in the mid-term.