Analyzing PV Loops has never been easier: New features in PV Loop v1.1 for LabChart

The PV Loop Module for LabChart for Windows allows you to record and analyze left ventricular pressure and volume data for assessing cardiac performance. Analyses can be conducted during sampling or on pre-recorded data.

You can display the pressure-volume loops, decide which loops to include and exclude from your analyses, and compute end-systolic and end-diastolic pressure volume relationships. A wide range of hemodynamic parameters can be calculated including pressure volume area, stroke work, and cardiac output. The module allows you to convert data to absolute volumes using cuvette calibration and to correct for parallel conductance using saline calibration.

New features in this version include:

Cuvette Calibration Settings now integrate with Analysis Manager allowing users to compare uncalibrated, RVU and cuvette calibrated volume data.

Plot regression information can now be copied as text to the Windows clipboard for a more straightforward approach to export the slope, intercept and model coefficient parameters into other documents.

Check and Uncheck All buttons (right) have been added to the Haemodynamics Table options to allow users to select the parameters they require faster.

EDPVR in Loop View now defaults to the exponential model (right). Passive stretch-tension during the early ventricular filling phase is largely determined by the elastic properties of the polypeptide filament titin, which spans from one M-line to another inside the cardiac myofibril. Passive stretch-tension during late ventricular filling, however, is determined by the polypeptide filament collagen which resides in the extracellular connective tissue and prevents overstretching.

Since the elastic modulus properties of each filament differ, this explains why the passive stretch-tension relationship during the filling phase is non-linear and why the default curve fit should be exponential, rather than linear.

Warnings for negative volumes and negative pressures (right) in an analysis are provided to alert users. Left-ventricular volume values that are negative result in the incorrect detection of end of systole. Negative pressure values prevent the use of an exponential model to describe the EDPVR.

Other haemodynamics parameters such as cardiac efficiency, pressure volume area, and potential energy will fail to be computed if volume or pressure data are negative. 

New script commands, “ApplyPVLoopCalibration” and “DisablePVLoopCalibration”, have been to the Macro editor to control Cuvette Calibration.

PV Loop Help File is now also available in Japanese and is now available with Japanese installs of LabChart.