Evaluation of changes in left ventricular myocardial function observed in canine myocardial dysfunction model using a...

Area of Science:

• Cardiovascular Physiology
• Echocardiography
• Biomedical Engineering

Background:

• Sustained high electrical pacing can alter myocardial function.
• Assessing these changes requires sensitive and accurate measurement techniques.
• Left ventricular (LV) function is critical for cardiac output.

Purpose of the Study:

• To evaluate the efficacy of two-dimensional tissue tracking (2DTT) in assessing myocardial function changes.
• To investigate the impact of sustained high electrical pacing on LV myocardial function in a canine model.
• To quantify global and regional strain alterations and pacing-induced dyssynchrony.

Main Methods:

• Implanted pacemakers at the right ventricular (RV) apex in five female Beagles.
• Performed sustained high electrical pacing at 250 beats per minute (bpm) for three weeks.
• Utilized conventional echocardiography and 2DTT at baseline and weekly intervals.

Main Results:

• Three weeks of pacing significantly reduced global radial and circumferential strains (p < 0.001).
• Regional analysis showed decreased segmental strains and increased radial dyssynchrony (p = 0.0007).
• 2DTT successfully measured strain changes and assessed myocardial function and dyssynchrony.

Conclusions:

• Two-dimensional tissue tracking (2DTT) is a valuable tool for evaluating myocardial function during high electrical pacing.
• Sustained high pacing significantly impairs both global and regional left ventricular (LV) myocardial function.
• 2DTT can quantify pacing-induced cardiac dyssynchrony, offering insights into cardiac adaptation and dysfunction.