Cardiac arrhythmia induced by hypothermia in a cardiac model in vitro

Patients that have survived Out-of-Hospital Cardiac Arrest usually develop some degree of neurological problems. A common treatment to mitigate neurological damage is mild therapeutic hypothermia (MTH). However, MTH has adverse effects, including arrhythmia. In order to explore the mechanisms of arrhythmia linked to MTH, we took measures on a temperature controlled experimental model which simulates MTH. These measures consisted of extracellular potential of cardiac culture on a multi-electrode array and we analysed them in terms of nonlinear dynamics. The results showed that cardiac arrhythmia is induced around temperature 35°C (spiral waves at T~35°C against plane waves at other temperatures). A period-doubling phenomenon is also observed around T=35°C, confirmed with the analysis methods. All results showed that 35°C is a critical temperature triggering arrhythmia. This suggests that the re-warming / cooling speed could affect the arrhythmia generation after MTH.