Analysis of the Left Ventricular Contractile Reserve Using End-systolic Pressure-Volume Relation (ESPVR) in Idiopathic Dilated Cardiomyopathy: Its Correlation with Pathologic Findings

ABSTRACT

BACKGROUND: Left ventricular (LV) end-systolic pressure volume relation (ESPVR) is considered as a load independent contractile index. However, its application in human beings has been limited by the difficulty in the accurate real time measurement of the LV volume changes. With introduction of the echocardiographic automatated edge detection method, on-line generation of multiple LV pressure volume-loops has become possible to assess ESPVR. This study was performed to investigate the correlation of the degree of myocardial damages with myocardial contractility and contractile reserve assessed by ESPVR as a surrogate of contractility index. METHODS: Studies were attempted in ten patients with idiopathic dilated cardiomyopathy. Baseline two-dimensional and Doppler echocardiography, cardiac catheterization for hemodynamic assessment and endomyocardial biopsy were performed. Generation of multiple LV pressure-volume loops during occlusion and release of the inferior vena cava by a balloon catheter was performed using the volume signals from the echocardiographic automatated edge detection method and the pressure signals from a 5F fluid-filled lumen catheter. ESPVR was measured at the baseline and after 3 minutes of dobutamin infusion (10 microgram/Kg/min). RESULTS: No correlation was observed between the degree of myocyte hypertrophy change or interstitial fibrosis and the two-dimensional echocardiographic or hemodynamic data. However, restrictive LV filling pattern was more common in the patients with severe degree of myocyte hypertrophy change. Myocardial contractility and contractile reserve were also significantly reduced in this patient group. The degree of interstitial fibrosis did not affect myocardial contractility or contractile reserve in this particular patient group. CONCLUSION: Assessment of ESPVR using the echocardiographic automatated edge detection method was feasible in the patients with idiopathic dilated cardiomyopathy. The degree of myocardial hypertrophy change was prominent in the patients with reduced contractility and contractile reserve.