Abstract 15031: Defining a Coupling Ratio: Tissue Doppler Velocities in Systole and Diastole Predict Greater Diastolic Than Systolic Impairment in Hypertrophic Cardiomyopathy

Abstract

Introduction: Mitral annular velocities, E’ and S’, (cm/s) measured by Tissue Doppler Imaging, are used in clinical cardiology and in research as important descriptors of systolic and diastolic function. We hypothesized that the relationship between these velocities in normal individuals would be linear, and would define a ventricular systolic/diastolic coupling ratio. We further hypothesized that departure from this normal coupling ratio might provide insight into certain disease states. Methods: We reviewed consecutive ECHOs performed at our institution to define the coupling ratio in normal individuals (n=57) and in 2 disease states dilated cardiomyopathy (DCM) (n=20), and hypertrophic cardiomyopathy (HCM) (n=19). The average of peak septal and lateral velocities, obtained in systole and diastole were compared (ANOVA). Results: Baseline characters as depicted in the table. In normals, there is a linear relationship between S’ and E’. While the S’ and E’ velocities are lower in absolute terms in DCM, the coupling ratio is similar to that seen in Normals. HCM, by contrast shows a relatively lower coupling ratio than Normals or DCM (Figure attached). Conclusion: We have defined a simple coupling ratio of systolic and diastolic velocities in normal and cardiomyopathy. The greater relative impairment on diastolic velocities in HCM appears to reflect a greater relative impairment in diastolic filling than in systolic shortening. In other words, for a given degree of systolic fiber shortening, fiber lengthening/stretch and perhaps utilization of the Frank Starling mechanism would be disproportionately impaired.