Medical University of South Carolina

Shahryar Chowdhury, MD, Primary Investigator
Charleston, SC
Research project: Validation of Non-Invasive Measures of Contractility in the Pediatric and Congenital Heart Disease Population
Amount funded: $15,000

Advances in medical and surgical therapy have advanced to the point where even children with the most severe heart disease are living well into middle age. Focus has shifted from preventing mortality to preserving cardiac function. In order to protect myocardial contractility we must be able to accurately measure it. Measurement of myocardial function is currently done qualitatively or using measurements that have proven to be unreliable. The gold-standard measurements of myocardial function are obtained through pressure-volume loop analysis. With the development of pediatric-sized conductance catheters we can now perform these measurements in children. The proposed study will compare non-invasive measures of function, such as those derived from non-invasive pressure-volume loop (PVL) analysis and 3D-speckle-tracking echocardiography (3D-STE), against the gold-standard measures of contractility.

Specific Aim # 1: Assess agreement and correlation of non-invasively derived indices of contractility against invasive measures of contractility obtained via conductance in children.

Specific Aim # 2: Assess the application and provide reference values for these same non-invasive indices in a large cross-sectional pediatric population.

There will be two arms to this study, 1) validation arm and 2) outpatient arm. In the validation arm, patients with biventricular anatomy undergoing left heart catheterization in the pediatric catheterization laboratory will be enrolled prospectively to have PVL analysis of the left ventricle. Measures of correlation between invasive and non-invasive measures of contractility will then be calculated. We estimate 30 subjects in this arm with subgroup of 10 patients with left sided obstructive lesions. The second, outpatient arm of patients will be recruited prospectively from our pediatric cardiology outpatient clinic. All patients with a normal echocardiogram will be approached for enrollment. We expect to enroll a minimum of 200 patients into this arm. We will propose reference values based on these results and assess for inter- and intra-observer variability.

The ideal tool for measuring myocardial contractility in children would be non-invasive, quick, load independent, with low intra- and inter-observer variability, and be validated invasively in children against the gold standard. The indices examined in the proposed study have the potential to meet these criteria and could be moved from the laboratory to the bedside. Applying these newly validated measures could significantly advance our ability to extend and enrich the lives of children born with congenital heart defects.