Monitoring of cardiac function by miniaturized accelerometers attached to the heart is becoming more frequently used, for example, these sensors can be found in pacing electrodes for cardiac resynchronization therapy1–3. Similarly, accelerometers may also be incorporated in the temporary pacemaker leads that are attached to the heart during cardiac surgery and later retracted through the chest after a few days. Addition of such a sensor to the pacemaker lead will allow measurements of cardiac motion without adding complexity to the surgical procedure, thus providing a new method for continuous monitoring of cardiac function in these patients. This can be useful for assessing the response to medication and may lead to earlier detection of cases with myocardial dysfunction.
In order to assess cardiac function by using accelerometers, functional indices need to be extracted from the sensor signal. Our group has performed several studies with epicardially attached accelerometers and demonstrated that such accelerometer recordings can be used for monitoring cardiac function. Velocity and displacement, calculated by integrating the acceleration signal once and twice, respectively, have been shown to give valuable functional information. Another functional index can be derived by combining displacement with measurements of left ventricular (LV) pressure to generate pressure–displacement loops. This builds on the classical pressure–volume loop principle for analysis of cardiac function which also has inspired other novel loop-analysis methods such as the pressure-strain loop method.
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Automatic detection of valve events by epicardial accelerometer allows estimation of the left ventricular pressure trace and pressure-displacement loop area - PubMed (nih.gov)
Sci Rep. 2020 Nov 18;10(1):20088.
Ali Wajdan, Magnus Reinsfelt Krogh, Manuel Villegas-Martinez, Per Steinar Halvorsen, Ole Jakob Elle, Espen Wattenberg Remme