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

D-PO05-033 - Relations Between Ventricular Arrhythmia And Electromechanical Window In Children And Young Adults With Hypertrophic Cardiomyopathy - A Novel Parameter For A Risk Stratification Of Sudden Cardiac Death (ID 1327)

 M.K. Song: Nothing relevant to disclose.


Background: Hypertrophic cardiomyopathy (HCM) is a leading cause of death in the young, largely due to ventricular arrhythmia. Prolonged action potential duration and increased mechanical dispersion of myocardium have been identified in patients with HCM and they might be related to ventricular arrhythmia. Electromechanical window (EMW), which reflects the relationship between the duration of electrical systole and the duration of mechanical systole, was studied in patients with long QT syndrome as a risk factor for arrhythmic events. However, EMW was not evaluated in patients with HCM.
Objective: We evaluated ECM in pediatric and young adults with HCM and the relationship between ECM and life-threatening events.
Methods: EMW was defined as the time interval between the Q wave and aortic valve closure (QAVC) minus QT interval (QAVC - QT interval), which was measured using continuous Doppler by echocardiography in left ventricular outflow tract.
Results: We identified 54 children and young adults (male 38, 70%) with HCM at a single tertiary center. The median age at study was 12.5 years (I.Q. 5.3 - 19.3 years). Fourteen patients with Noonan syndrome, 3 patients with Pompe disease and 2 patients with Danon disease were included. EMW of HCM patients were compared to 30 age-matched control. HCM patients had negative EMW while normal control had positive EMW (-54.8 ± 52.7 vs. 16.6±15.7ms, p<0.001). Life-threatening event (LTE) was in 13 patients (24%) and aborted sudden cardiac death or ventricular fibrillation was in 8 (15%). HCM patients with LTE had more negative EMW (-96.4±57.6 vs. -41.6±44.1ms, p=0.001). LTE was associated with the z-score of interventricular septal thickness, nonsyndromic HCM and EMW (p=0.009, 0.033, and 0.001, respectively. On multivariate analysis, EMW was an independent risk factor for LTE (Odds ratio 0.98, 95% C.I. 0.966-0.995, p=0.008).
Conclusion: Patients with HCM had negative EMW while healthy individuals had positive EMW. Profound EMW negativity correlates with life-threatening events in HCM.