Where Would You Go?
CONGENITAL HEART DISEASE SERIES
"Where Would You Go?"
(c) 2017 Dr. Sherry-Ann Brown
I've always felt there should be a "Congenital Heart Disease for Dummies" (like me) or "Congenital Heart Disease Made Simple" (for people like me). So far, I am yet to come across it. If you know of it and I missed it, please send it to me. For now, here is Installment 1 of my version. The series is entitled, "Where Would You Go?"
Image credit: www.wikipedia.org
Part 1: Spinning Around in Circles
If you were oxygenated blood coming out of the pulmonary veins from the lungs into the left atrium and you have no left ventricle of any useful size to head into, where would you go? If you can't backtrack into the pulmonary veins, and you can't bore your way into the left ventricle, but maybe you could make a hole somewhere else, where would you go? How would you get to the lungs? What might be the most natural way?
Spinning around in circles in the left atrium, you might decide to create a hole in the atrial septum and make your way into the right atrium. Then where would you go from there? Well, naturally, you would head through the tricuspid valve into the right ventricle, then voila! You are in the pulmonary artery on your way to the lungs.
Then what? You find yourself again - oxygenated blood coming out of the pulmonary veins from the lungs into the left atrium and you have a left ventricle which is so tiny that it is of no useful size (ok, let's call it a 'hypoplastic left heart') to head into, where would you go?
You might head through the hole in the atrial septum (let's call it an 'atrial septal defect' or ASD) into the right atrium, down through the tricuspid valve into the right ventricle, and voila! Into the pulmonary artery to be oxygenated again.
You realize that you are in a cycle of blood flow that never gets to the rest of the body. You are stuck in the heart and the lungs alone. Where might you go? First of all, you think back to your roots. Where did you go before you left your mother's womb. The PATENT DUCTUS ARTERIOSUS (PDA)!!!! In the womb, you went from the pulmonary artery to the aorta carrying oxygenated blood. Why can't you do it again?
So, this time, you find yourself again - oxygenated blood coming out of the pulmonary veins from the lungs into the left atrium; you head through the hole in the atrial septum (the ASD) into the right atrium, down through the tricuspid valve into the right ventricle, into the pulmonary artery to be oxygenated again. While you send some of your portion off to be re-oxygenated in the lungs and come around again, for now you head from the pulmonary artery through the PDA into the aorta, and to the rest of the body!
Eventually, you make your way back from the rest of the body, having thoroughly enjoyed that adventure, back to the right heart from the superior and inferior vena cavae, into the right atrium, down through the tricuspid valve into the right ventricle, and into the pulmonary artery. Some of your portion ends up recycling to the body again inefficiently, but much of you heads into the lungs for oxygenation and back through the pulmonary veins into the left atrium and through the ASD, and....you see how this goes.
That's how the human body survives with a hypoplastic left heart.
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Dr. Sherry-Ann Brown