Continuous and Autonomous Monitoring of Changes in Left Ventricular dP/dt_max Using an Epicardial Accelerometer.

Area of Science:

• Biomedical Engineering
• Cardiovascular Physiology
• Medical Device Technology

Background:

• Assessing cardiac contractile function typically relies on invasive or intermittent methods, limiting continuous monitoring.
• Epicardial accelerometers offer potential for cardiac function monitoring but often underutilize signal data.
• Existing techniques lack the spatial and temporal resolution for reliable, continuous clinical assessment.

Purpose of the Study:

• To develop a method for reconstructing epicardial accelerometer position in 3D space.
• To enable the extraction of cardiac function indices in a Lagrangian frame of reference.
• To introduce a novel surrogate indicator for cardiac contractility using accelerometer data.

Main Methods:

• Reconstruction of epicardial accelerometer 3D position.
• Extraction of cardiac function indices in a Lagrangian frame.
• Calculation of the standard deviation of Lagrangian acceleration (${\sigma }_{\mathrm{Acc}}$) per heartbeat.

Main Results:

• The standard deviation of Lagrangian acceleration (${\sigma }_{\mathrm{Acc}}$) was identified as a novel indicator of contractility.
• Changes in ${\sigma }_{\mathrm{Acc}}$ strongly correlated with changes in maximum rate of change of left ventricular pressure.
• Strong correlation observed in animal data (n=29) across diverse hemodynamic conditions.

Conclusions:

• This proof-of-principle study introduces a new method for assessing cardiac contractility using epicardial accelerometers.
• The findings suggest potential for long-term, continuous monitoring of heart function.
• Epicardial accelerometers can be utilized as versatile, autonomous monitoring devices for cardiac health.