[Cold-induced arrhythmias in the isolated rabbit atrium studied by mapping]

Area of Science:

• Cardiology
• Electrophysiology
• Cardiac Arrhythmia Research

Context:

• Investigating the electrophysiological effects of hypothermia on cardiac tissue.
• Utilizing isolated rabbit atria as a model system for studying arrhythmias.
• Employing multielectrode mapping to analyze cardiac electrical activity.

Purpose:

• To determine the incidence and mechanisms of arrhythmias induced by cooling in isolated rabbit atria.
• To explore the role of re-entry in the development of hypothermic arrhythmias.
• To assess the reversibility of cooling-induced arrhythmias.

Summary:

• Cooling isolated rabbit atria to 27°C induced arrhythmias in 10 out of 12 preparations.
• Multielectrode mapping revealed that 60% of these arrhythmias were caused by functional re-entry.
• In the remaining 40%, re-entry was not directly mapped, but arrhythmias correlated with decreased wavelength, suggesting a re-entry mechanism.
• The observed arrhythmias were reversible upon returning the tissue to normal temperature.

Impact:

• Provides evidence for re-entry as a primary mechanism underlying hypothermic arrhythmias in atrial tissue.
• Highlights the sensitivity of cardiac electrical activity to temperature changes.
• Offers insights into the pathophysiology of arrhythmias that may occur during hypothermic medical procedures.