Abstract 2433: Single-Beat Estimation of the Left Ventricular End-Diastolic Pressure-Volume Relationship in Heart Failure Patients
A previously proposed method to predict the end-diastolic pressure-volume relationship (EDPVR) from a single pressure-volume point was tested in heart failure patients. Patients (NYHA III–IV) scheduled for mitral annuloplasty (n=9) or surgical ventricular restoration (n=10) and patients with normal left ventricular function undergoing CABG (n=12) were instrumented with pressure-conductance catheters. Pressure- volume loops were measured pre- and post-surgery. Data obtained during gradual vena cava occlusion provided directly-measured EDPVRs. Baseline end-diastolic pressure (Pm) and volume (Vm) were used for single-beat prediction of EDPVRs. Accuracy, quantified by root-mean-squared-error (RMSE) between measured and predicted EDPVRs, was 2.79±0.21mmHg. Measured vs. predicted end-diastolic volumes at fixed pressure levels (5–20mmHg) showed tight linear correlations (R2: 0.687–0.886). End-diastolic volumes were significantly different between groups, but two-way ANOVA indicated that differences between groups were not dependent on the method (i.e. measured vs. predicted). RMSEs were not different between groups or dependent on Vm or Pm, indicating that EDPVR prediction was equally accurate over a wide volume range. Single-beat derived EDPVRs obtained from hearts spanning a wide range of sizes correlated well with directly-measured EDPVRs. The single-beat method facilitates less invasive estimation of the EDPVR, particularly when coupled with emerging noninvasive techniques to measure pressures and volumes.