Abstract 11194: Classic Pattern Dyssynchrony is Associated With Left Bundle Branch Block in Pediatric Dilated Cardiomyopathy
Classic pattern dyssynchrony (CPD) has been associated with > 90% response to cardiac resynchronization therapy (CRT) in adults with dilated cardiomyopathy (DCM), but has not been evaluated in pediatric DCM. CPD is defined by early septal contraction (figure 1 yellow curve) opposed by early LV wall stretch with delayed contraction (red curve). As some DCM children may benefit from CRT, our goal was to determine the frequency and associations of CPD in this population. We hypothesized that CPD is present in a minority of pediatric DCM subjects.
Subjects ≤ 20 years old with DCM (LV end diastolic diameter Z score > 2 & LVEF < 40%) had 2D longitudinal speckle tracking echo strain analysis (EchoPAC) analyzed for CPD. ECG was evaluated for strict adult LBBB morphologic criteria modified with QRS duration > 98th% for age/sex. Continuous variables reported as mean ± SD. Groups were compared with Fisher’s exact, t-tests and Pearson’s correlation (p ≤ 0.05 significant).
Mean age was 5.3 years (29 infants, 16 toddlers/children, 13 adolescents) with 47% male. DCM diagnoses were 32 idiopathic, 14 familial, 5 post-chemotherapy, 5 post-myocarditis and 2 with arrhythmia. LV indexed end-diastolic diameter was 5.0 ± 1.4 mm/m2 (Z score 6.4 ± 2.5); LVEF was 24 ± 9%. CPD was seen in 8 (15%) subjects and was associated with prolonged QRS in 6/8 (p=0.005) and a LBBB pattern in 4/8 (p<0.001). QRS duration was prolonged in 11 (19%), but only 4 (7%) met strict LBBB criteria (4/4 with CPD). Trends in the CPD group towards younger female with lower LVEF and increased LV dilation were not statistically significant (p 0.14-0.68). One CPD infant underwent CRT and responded by LVEF and clinical status.
In this pediatric DCM cohort with moderate-severe disease, 15% had CPD pattern, which was statistically associated with LBBB and prolonged QRS. As CPD has been associated with high response to CRT in adults, further research is needed to determine its contribution to LV dysfunction and CRT response in pediatric DCM.
- © 2013 by American Heart Association, Inc.