Ventricular fibrillation during cardiopulmonary bypass

Area of Science:

• Cardiovascular Science
• Cardiac Electrophysiology
• Myocardial Ultrastructure

Background:

• Induced ventricular fibrillation (VF) can cause myocardial damage.
• Understanding ultrastructural changes is crucial for assessing cardiac injury and recovery.
• The canine heart model is frequently used to study cardiac events.

Purpose of the Study:

• To investigate the ultrastructural changes in the canine myocardium following induced ventricular fibrillation.
• To compare subendocardial and subepicardial layers for differential injury patterns.
• To evaluate the reversibility of observed ultrastructural changes.

Main Methods:

• Utilized a transmural myocardial biopsy method in normothermic, nonhypertrophic canine hearts.
• Quantitatively evaluated ultrastructural changes in mitochondria and glycogen granules.
• Compared subendocardial and subepicardial myocardial layers.

Main Results:

• Ventricular fibrillation induced slight myocardial abnormalities including interstitial edema, mitochondrial derangement, contraction bands, and capillary endothelium swelling.
• No significant ultrastructural differences were observed between subendocardial and subepicardial layers.
• Observed pathological changes were at least partially reversible.
• Mitochondria and glycogen granules were quantified and found to be well preserved.

Conclusions:

• Myocardial ultrastructure is affected by ventricular fibrillation but demonstrates reversibility.
• The canine myocardium may exhibit resilience to the no-reflow phenomenon post-VF, evidenced by preserved mitochondria and glycogen.
• These findings suggest potential therapeutic targets for mitigating ischemia-reperfusion injury after cardiac arrest.