Epicardial surface dynamics in the closed-chest normal canine

Area of Science:

• Cardiovascular physiology
• Biomedical imaging
• Medical physics

Background:

• Previous heart motion studies were limited to few locations and often invasive.
• Surgical procedures can alter the natural cardiac cycle measurements.
• Accurate, non-invasive methods are needed for detailed cardiac dynamics assessment.

Purpose of the Study:

• To develop and validate a non-invasive imaging technique for precise cardiac surface motion measurement.
• To investigate the three-dimensional heart shape changes during the cardiac cycle.
• To provide data for biomechanical models of heart deformation.

Main Methods:

• Utilized Compton backscatter imaging for high-precision displacement and velocity measurements.
• Acquired data from over 200 epicardial locations at 13 ms intervals.
• Achieved measurement precision of 0.1 mm (S.D.) without surgical intervention or contrast agents.

Main Results:

• Demonstrated vigorous inward motion of left ventricle (LV) and right ventricle (RV) surfaces during isovolumic relaxation and early rapid refill.
• Observed velocities during relaxation that equal or exceed those during ejection.
• Detailed spatial and temporal patterns of LV motion during ejection, with posterior motion significantly greater than anterior.

Conclusions:

• Compton backscatter imaging provides undisturbed, precise measurements of cardiac dynamics in a closed chest.
• This technique has potential as a non-invasive clinical tool for assessing cardiac surface motion abnormalities.
• The collected data can inform biomechanical models of heart deformation.