Papillary Muscle Action Potential Alterations After Abdominal Ischemia-Reperfusion

Abdominal aortic aneurysm (AAA) has a high prevalence and surgical treatment is still the best option for many reasons. Surgical treatment needs abdominal blood flow to be discontinued, which leads to secondary complications caused by ischemia-reperfusion (I/R) in different organs. Since distant organ damages are seen after surgery, abdominal ischemia reperfusion results in post-treatment deaths especially due to heart based problems. In this study, we aimed to investigate the possible alterations in action potential parameters of papillary muscle after abdominal I/R injury. Adult Wistar-Albino rats were divided into two groups randomly: SHAM group (only laparotomy was performed) and I/R group (abdominal aorta was clamped for 1 hour and reperfused for 2 hours). After the operational period, left ventricle papillary muscles were isolated and action potential (AP) recording experiments were carried out in-vitro. Significant hyperpolarization was seen in resting membrane potential in I/R group. There was no alteration in the general shape of the action potential after I/R. Some delayed-after-depolarizations were recorded, that suggests an impaired persistent Na+ channel activity when interpreted with resting membrane potential findings. This study shows that I/R does not affect the AP parameters except for resting membrane potential. However, it is also likely that the sodium-calcium exchanger (NCX) causes delayed arrhythmias after depolarization due to dysfunction of unknown causes