Pediatric/Adult Congenital Heart Disease -> Pediatric Cardiology D-PO05 - Poster Session V (ID 39) Poster

D-PO05-034 - Is There A Role For Cardiac Resynchronization Therapy In Pediatric Idiopathic Pulmonary Hypertension?: A Study Of The Electrical Activation Patterns Utilizing 3d Mapping (ID 616)


Background: Cardiac Resynchronization Therapy (CRT) has been proposed as heart failure therapy for pulmonary hypertension (PH) patients. PH patients show evidence of mechanical and electrical dyssynchrony (ED) by QRS duration but a more detailed evaluation of the patterns of ED in this population has not been described.
Objective: To evaluate the patterns of ED in pediatric idiopathic PH patients using 3D mapping (3D-M) compared to normal subjects.
Methods: Using 3D-M, a minimum of 200 activation sites were sampled throughout the RV of PH and normal subjects. Local activation time (LAT) was defined as the time from surface ECG Q-wave onset to the onset of depolarization at each site. Average LATs at the Septum, Apex (RVA), Free Wall (FW), TV Annulus (TWA), and RVOT were analyzed for relative activation timing and sequence.
Results: There was no difference in age between the 10 PH and 7 control patients (10.7±3.8 vs 13.8±4.1 yrs, p=0.13). The average PVRi was 15.9 ± 11 WU and RVEF was 36 ± 12% in the PH group. PH patients had a longer QRSd (99.3±15.8 vs 83.5±6 msec, p=0.02) than controls but there was no difference in RV total activation time (55.7±10.8 vs 56.2±4.2 msec, p=0.9). The septum was the earliest activation site in both control and PH groups. In all normal subjects, septal activation was followed by RVA and then FW. In contrast, septal activation was followed by FW and then RVA in all PH subjects.
Conclusion: Pediatric PH patients have electrical dyssynchrony as evidenced by prolonged QRS duration and abnormal activation sequence in the RV compared to normal controls. This abnormal electrical activation may contribute to the development of RV failure and could be a potential target for CRT.