Cardiac reflections and natural vibrations: force-frequency relation recording system in the stress echo lab
Tonino Bombardini1, Vincenzo Gemignani, Elisabetta Bianchini
1Department of Echocardiography (Echo Lab), IFC, CNR, Pisa, Italy. tbombardini@yahoo.it
Cardiovascular Ultrasound
|November 23, 2007
Summary
A new precordial cutaneous sensor can accurately measure the cardiac force-frequency relation (FFR), offering an objective, noninvasive alternative to stress echocardiography for assessing contractile reserve. This method shows promise for daily exercise and home monitoring applications.
Area of Science:
- Cardiology
- Biomedical Engineering
- Medical Diagnostics
Background:
- The cardiac force-frequency relation (FFR) describes the myocardium's ability to increase contraction force with higher heart rates.
- Current FFR assessment relies on stress echocardiography, which is invasive and operator-dependent.
- An ideal FFR assessment would be noninvasive, objective, and imaging-independent.
Purpose of the Study:
- To assess the feasibility of measuring cardiac force using a precordial cutaneous sensor.
- To develop a heart rate-dependent force variation curve using the sensor.
- To compare sensor-derived FFR with standard stress echocardiography FFR measurements.
Main Methods:
- A transcutaneous force sensor was applied to the precordial region in 88 patients undergoing various stress tests.
- Myocardial vibration amplitude during isovolumic contraction measured cardiac force.
- FFR was calculated as force variation versus heart rate, with concurrent echocardiographic FFR measurements.
Main Results:
- Consistent FFR measurements were achieved in all patients using the sensor.
- Both sensor and echo-derived FFR correctly identified normal and abnormal contractile reserve.
- The sensor-derived FFR demonstrated high sensitivity (0.85) and specificity (0.77) with a cut-off value of 15.5 g * 10-3.
Conclusions:
- A precordial cutaneous sensor provides a feasible and operator-independent method for assessing cardiac FFR.
- This noninvasive approach accurately reflects myocardial contractile reserve and mirrors pressure/volume dynamics during stress.
- The technology is adaptable for daily exercise monitoring and potential home-based healthcare systems.
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