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Title: Restart heart? Post by: CarbonRobot on Jan 11, 2023 Is there anyway to restart a heart that has completely stopped? Or just defibrillation when beats are chaotic? How does a heart start in the first place?
Title: Re: Restart heart? Post by: duddy on Jan 11, 2023 A defibrillator cannot shock a heart back to life once it has completely stopped. In fact, a defib. stops the heart temporarily to bring it back to normal, but if it's already dead, it won't restart it.
Quote How does a heart start in the first place? If the cardiac tissue doesn't get the oxygen it needs, it will stop working. If enough of it doesn't receive oxygen, it throws the heart beat off balance, leading to cardiac arrest. Title: Re: Restart heart? Post by: CarbonRobot on Jan 13, 2023 A defibrillator cannot shock a heart back to life once it has completely stopped. In fact, a defib. stops the heart temporarily to bring it back to normal, but if it's already dead, it won't restart it. Quote How does a heart start in the first place? If the cardiac tissue doesn't get the oxygen it needs, it will stop working. If enough of it doesn't receive oxygen, it throws the heart beat off balance, leading to cardiac arrest. Yes, but in the womb. What starts the heart? Title: Re: Restart heart? Post by: bio_man on Jan 14, 2023 Interesting follow-up!
A baby's cardiovascular system begins developing three weeks after conception. Before then, the following occurs: The cardiovascular system's embryological development begins with cardiac progenitor cells' migration in the epiblast, just lateral to the primitive streak. These cardiac progenitor cells eventually develop into cardiac myoblasts. Within this same splanchnic layer of the mesoderm, so-called "blood islands" eventually undergo a period of vasculogenesis to form vascular structures. Coalescence of the blood islands eventually forms a region known as the cardiogenic field. The cardiogenic field is initially horseshoe-shaped and surrounded by cardiac myoblasts with the cardiogenic field's apex, eventually developing into primitive ventricles along with their respective outflow tracts. Ultimately, the cardiogenic field changes its configuration by cephalocaudal rotation. By doing so, it forms a primitive heart tube continuous with vascular structures. https://www.ncbi.nlm.nih.gov/books/NBK537313/ At around six weeks, the embryo develops a tube that generates sporadic electrical impulses that eventually coordinate into rhythmic pulses. I am assuming those electrical impulses are produced by the pacemaker cells. The pacemaker activity develops in the inflow tract of the primary heart tube and is the first element to function in the cardiac conduction system. Action potentials spread from the posterior inflow tract to the anterior outflow tract of the heart generating a wave of contraction. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1768983/ Title: Re: Restart heart? Post by: CarbonRobot on Jan 14, 2023 So hypothetically couldn't pacemaker cells or something in the brain be stimulated to start the heart indirectly since defibrillation can't help from a dead stop?
Title: Re: Restart heart? Post by: bio_man on Jan 14, 2023 Cells are considerably sensitive to hypoxia; some can't survive a few minutes without being replenished with oxygen. This is why heart attacks are time-sensitive I suppose because once those tissues are damaged, they have no more use
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