Body Surface Mapping of the Mechanical Cardiac Activity

Abstract

Introduction: Studies of the movement of the chest wall show their potential in the diagnosis of heart diseases. Few studies have focused on mapping these movements especially in the lower inaudible frequency band.Aims: This study evaluates Body Surface Mapping (BSM) as a method for describing mechanical cardiac activity.Methods: The chest wall's velocity was measured with a Laser Doppler Vibrometer (LDV) on six healthy subjects. The measuring procedure was repeated for 30 points positioned in a grid at the subjects chest. An electrocardiogram (ECG) and respiration was measured to support the signal processing. The heart movement were described using amplitude maps, constructed from the integrated LDV signal components of 1-20 Hz.Results: The impact of the cardiac motion on the displacement of the chest wall was shown as a typical pattern of the changes of the amplitude maps as a function of time.Conclusion: The results had a high reproducibility and were in concordance with existing evidence, thus indicating BSM to be a valid method for characterization of the mechanical cardiac activity.

Multichannel seismocardiography: an imaging modality for investigating heart vibrations

“…Laser Doppler vibrometry (LDV) has also been used to record mechanical vibration of the chest (Morbiducci et al 2007). Heart beats where recorded asynchronously using LDV from multiple sites to obtain vibration maps, where the signals were synchronized using the R-peaks of simultaneously recorded ECG (Munck et al 2016). Shirkovskiy et al (2018), found that using airborne ultrasound waves, chest vibrations could be recorded at a high spatial resolution (Shirkovskiy et al 2018).…”

“…Limitations of these systems are either a low spatial resolution (⩽5 channels) (Di Rienzo et al 2016, Lin et al 2018), asynchronous sampling (Munck et al 2016), or low temporal resolution (⩽157 samples per second) (Shirkovskiy et al 2018). To gain better insight in cardiac-induced chest surface vibrations, we designed and validated an accelerometer-based mchSCG system with 16 three-axis accelerometers with a synchronized maximum sample rate at 1000 Hz.…”

Airborne ultrasound surface motion camera: Application to seismocardiography

“…Although some initial work has been done on array-acquisition of SCG [10,11], physiological interpretation of these data remain either absent, or tenuously linked to individual valve events. This study's proposed system uses airborne ultrasonic waves to detect movement in a roughly 30×40 cm 2 area of interest without direct contact.…”

“…This study's proposed system uses airborne ultrasonic waves to detect movement in a roughly 30×40 cm 2 area of interest without direct contact. Some other methods were explored to achieve a similar purpose, namely laser speckle imaging [12,13], scanning laser vibrometry [11,14] and stereoscopic video [15]. These latter methods were dismissed due to their respective limitations: the lower sensitivity for techniques using video cameras [16], the necessity to synchronize heart beat ECG with laser vibrometer in the sequential scanning mode, the need to have a good reflective surface for all optical based systems.…”

“…These latter methods were dismissed due to their respective limitations: the lower sensitivity for techniques using video cameras [16], the necessity to synchronize heart beat ECG with laser vibrometer in the sequential scanning mode, the need to have a good reflective surface for all optical based systems. Furthermore, due to implementation difficulties all these techniques have usually been limited to 30 acquisition channels on ~ 25×25 cm 2 area [10,11].…”