The electrode array measures electrical conductance within the ventricular chamber, using blood conductivity as the basis for estimating volume. Because the catheter also records pressure at the same time, the system aligns volume changes with pressure changes during the cardiac cycle. This synchronized measurement allows investigators to examine ventricular performance continuously rather than relying on isolated pressure or volume readings.
Electrical signals do not arise exclusively from blood inside the ventricle; surrounding tissues also contribute to the measured conductance. This contribution, called parallel conductance, can distort volume estimates if it is ignored. Calibration accounts for that external component, improving the accuracy of calculated ventricular volumes and making subsequent pressure-volume analysis more reliable.
Pressure-volume loops display how ventricular pressure and volume change throughout each cardiac cycle. Their shape and measured characteristics support evaluation of stroke volume, contractility, and ventricular compliance, which describes how the chamber responds to filling. The recordings can also be used to derive load-independent indices of performance, helping distinguish intrinsic ventricular function from changing loading conditions.
A catheter containing pressure sensors and multiple electrodes is positioned inside the ventricle. The system then records intracardiac pressure and electrical conductance while the heart beats, generating synchronized pressure and volume data. Calibration is performed to account for conductance from surrounding tissues before investigators interpret ventricular volumes, pressure-volume loops, or derived measures of cardiac performance.
The combined recordings provide quantitative measures of stroke volume, contractility, and ventricular compliance, along with load-independent indices of performance. These outcomes allow researchers to assess both the amount of blood ejected and the ventricle’s mechanical behavior during filling and contraction. Examining several measures together gives a broader picture of cardiac function than a single pressure or volume value.
The technique is useful for studying heart failure, cardiac remodeling, and the effects of drugs or other interventions on ventricular function. Repeated pressure-volume measurements can show how an intervention changes contractility, compliance, stroke volume, or related performance indices. This makes the method relevant for evaluating functional consequences of disease progression and treatment within cardiovascular research.