Ventricular pressure–volume loops obtained by 3D real-time echocardiography and mini pressure wire—a feasibility study

Introduction Pressure–volume relations (PVR) provide vital information regarding ventricular performance and cardiac pathophysiology. Acquiring PVR by conductance catheter technology is invasive and laborious, which explains why the assessment of PVR is not used in clinical practice. Real-time three-dimensional echocardiography (3DE) allows almost instantaneous capture of ventricular volume changes throughout the cardiac cycle. The aim of the study was to assess the feasibility of 3DE combined with pressure data to calculate PVR in children and adolescents. Methods In 31 patients with congenital heart disease (age 3 days–22.7 years, weight 2.75–80.0 kg), ventricular pressure was recorded by a mini pressure wire during routine catheterization. Simultaneously, 3D datasets of the left or right ventricle were acquired for calculation of volume. PVR were generated from contemporaneous 3D volume and pressure data. Systolic myocardial elastance, ventriculo-arterial coupling, diastolic relaxation constant Tau and end-diastolic PVR were determined using a single-beat approach. Results Computation of PVR using non-invasive 3D volume data and pressure curves obtained by mini pressure wire was easy, feasible and reproducible. On average, 6 [3–11] PVR, needing an additional examination time of 6.5 ± 3.5 min, were acquired. Both intra- and interobserver variability were good for all measured parameters (coefficient of variation <10%). Conclusions Calculation of PVR from 3DE volume curves and simultaneous pressure data obtained by a mini pressure wire is a feasible method to assess cardiac function. Due to the tiny size of the pressure wire used, PVR can be acquired even in small neonates with congenital heart disease.