Prognostic implications of the systolic to diastolic duration ratio in children with idiopathic or familial dilated cardiomyopathy.

BACKGROUND

Childhood dilated cardiomyopathy (DCM) carries high morbidity and mortality. The echocardiographic systolic to diastolic (S:D) duration ratio, an indicator of global cardiac performance, is elevated in DCM; however, its prognostic implications have not been investigated in this population.

METHODS AND RESULTS

We investigated systolic and diastolic durations and the resultant S:D ratio using pulsed tissue Doppler imaging in children with idiopathic or familial DCM. We studied serial echocardiograms from presentation until the last follow-up echo. Results were compared with heart rate-matched controls and between DCM subgroups based on an acute or insidious presentation. The association between S:D ratio and death or need for transplant was analyzed. All analyses were adjusted for repeated measures per patient. We studied 200 serial echocardiograms of 48 children with DCM (7.0±6.0 years) and 25 controls. Adjusted for repeated measures through a compound symmetry covariance structure, the S:D ratio was higher in DCM patients (-0.425 [0.072]; P<0.001) because of shortened diastole. A S:D ratio >1.2 at presentation and on serial evaluation was associated with a hazard ratio of 10.5 (95% confidence interval, 3.9-27.8; P<0.001) for death or transplant. In combined multivariable analysis, a S:D ratio >1.2 remained significantly associated with hazard of death/transplant (hazard ratio, 9.1; P=0.04) after adjustment for ejection fraction (hazard ratio: 2.2 per -10%; P<0.001).

CONCLUSIONS

A high S:D ratio is associated with increased risk for death or need for transplant in children with DCM across the spectrum of heart rates and may be a useful prognostic index for serial evaluation of children with DCM.