Characterization of Left Ventricular Diastolic Function by Tissue Doppler Imaging and Clinical Status in Children with Hypertrophic Cardiomyopathy

Background-Conventional transmitral Doppler indices are unreliable in assessing clinical status in patients with hypertrophic cardiomyopathy (HCM) because they are affected by loading conditions. This study sought to determine whether tissue Doppler velocities are predictive of adverse clinical outcomes including death, cardiac arrest, ventricular tachycardia (VT), significant cardiac symptoms, and exercise capacity in children with HCM. Methods and Results-We studied 80 consecutive children (median age 12 years, median follow-up 26 months) evaluated at 1 hospital from January 1999 to August 2003 compared with 80 age- and gender-matched controls. Patients underwent echocardiography, ambulatory Holter monitoring, and upright exercise testing. Children with HCM had significantly decreased early diastolic tissue Doppler velocities at the lateral mitral (13.2 versus 19.3 cm/s), tricuspid (13.3 versus 16.3 cm/s), and septal (9.4 versus 13.5 cm/s) annuli compared with controls (P<0.001 for each comparison). By forward stepwise regression analysis, early transmitral left ventricular filling velocity (E)/septal Ea ratio predicted death, cardiac arrest, or VT (r=0.610, R²=0.37, P<0.001). Peak oxygen consumption (Vo₂) was most predictive of children who developed symptoms (r=0.427, R²=0.182, P<0.001). Peak Vo₂ correlated inversely with E/Ea septal ratio (r=-0.740, P<0.01). Conclusions-Transmitral E/septal Ea ratio predicts children with HCM who are at risk of adverse clinical outcomes including death, cardiac arrest, VT, and significant cardiac symptoms. Peak Vo₂ correlated with peak exercise capacity in HCM patients.