Epicardial mapping of segmental myocardial function: an echocardiographic method applicable in man

Area of Science:

• Cardiology
• Medical Imaging
• Surgical Technology

Background:

• Assessing segmental myocardial function intraoperatively is crucial for guiding cardiac surgery.
• Existing methods may lack the resolution or real-time feedback needed for precise functional mapping.

Purpose of the Study:

• To develop and validate a high-resolution epicardial echocardiography technique for mapping segmental myocardial function.
• To assess the technique's utility in identifying myocardial ischemia and evaluating the effects of coronary artery bypass grafting.

Main Methods:

• Utilized a miniaturized, fingertip-worn M-mode echocardiographic transducer (7.5 MHz).
• Characterized the technique in a canine model of induced myocardial ischemia.
• Validated findings against Rhodamine fluorescence perfusion maps and human coronary bypass surgery data.

Main Results:

• The technique accurately detected reduced segmental thickening and systolic thinning in ischemic myocardium within seconds.
• Epicardial echocardiography identified akinetic transmural infarctions and hypokinetic segments distal to coronary stenosis.
• Demonstrated intraoperative assessment of functional changes post-coronary bypass grafting in human subjects.

Conclusions:

• Epicardial echocardiographic mapping is a practical tool for intraoperative assessment of myocardial function.
• This technique enhances understanding of coronary disease pathophysiology and surgical intervention effects.
• Offers potential for improved decision-making during cardiac surgery.