"After clinical death, which is characterized by the cessation of blood circulation"
WAT. So it’s beating but zero bp etc, so it’s like a human going into A-fib?
Cool article. I don’t entirely understand
It’s not atrial fibrillation. That just stops normal sinus rhythm (NSR) where their sinoatrial node causes atrial contraction to fill the ventricle in diastole prior to systolic contraction of the ventricle and systemic circulation of blood. So the rhythm is irregular because the intrinsic “pacemaker” of the heart isn’t working and ventricular filling is often impaired
the only way a heart continues to contract without any circulation would be one of two ways. Total coagulation of the circulating blood, so contraction cannot cause circulation due to total obstruction of blood flow, or PEA, pulse less electrical activity. PEA can look very similar to NSR on an EKG, and if you look directly at a beating heart (actually visualize the heart) it appears to be still contracting but it produces no or little systemic circulation. Humans do this too. I don’t know how long a human heart can maintain this, but PEA is still dead. The SA node has some spontaneous activity that allows depolarization and contraction without any outside stimulus from the rest of the body
Days seems like a long time, but animals that can maintain life during torpor may have a stronger drive to keep the heart beating intrinsically to the heart. For keeping humans alive, it requires oxygen. We can keep lungs moving and hearts beating in completely dead people (brain dead). We use mechanical ventilation and blood pressure support medications to make blood go round and round and lungs going up and down in humans all the time prior to their organ donation for transplant
But beating with no circulation is different, it would be interesting to understand the pacemaker physiology in reptiles. I guess I’ll dig up the reptile medicine texts again and read about it more
Thanks
@kinyonga
