Relative ventricular volume measurements by intracardiac impedance

Area of Science:

• Cardiovascular Physiology
• Biomedical Engineering
• Medical Instrumentation

Background:

• Accurate monitoring of right ventricular volumes is crucial for assessing cardiac function.
• Current methods for measuring these volumes can be invasive or limited in real-time application.
• Electrical impedance techniques offer a potential non-invasive alternative for hemodynamic monitoring.

Purpose of the Study:

• To determine if DC-coupled electrical intracardiac impedance signals can detect changes in right ventricular end-diastolic and end-systolic volumes.
• To evaluate different measurement configurations for their effectiveness in detecting these volume changes.

Main Methods:

• Investigated DC-coupled electrical intracardiac impedance signals in 13 pacemaker patients.
• Tested various measurement configurations (quadrupolar, tripolar, intraventricular bipolar).
• Induced right ventricular volume changes via incremental overpacing and postural alterations.
• Used peripheral blood pressure pulse contour systolic integral as a stroke volume marker.

Main Results:

• DC-coupled impedance successfully detected right ventricular volume changes.
• Quadrupolar configurations provided superior amplitude resolution for impedance signals.
• Tripolar and intraventricular bipolar configurations demonstrated better correlation with hemodynamic changes.

Conclusions:

• DC-coupled electrical impedance is a viable method for detecting right ventricular volume variations.
• Configuration choice impacts signal resolution and hemodynamic relevance.
• Further research into optimal configurations could enhance non-invasive cardiac monitoring.