Prognostic Implications of the Systolic to Diastolic Duration Ratio in Children With Idiopathic or Familial Dilated Cardiomyopathy
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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.
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