Video narration
After stairs, you feel your pulse: your heartbeat is moving blood. But how does blood reach the lungs when no heart chamber pumps it there? Normally, the heart sends blood to the lungs for oxygen. It returns, then gets pumped out to your body. Fontan circulation is a rerouted blood path used when there's only one working pumping chamber: no ventricle pumps blood toward the lungs. Here's the flip: blood still gets there. Veins bringing blood back from the body connect directly to the arteries leading to the lungs. Blood returning from the lungs reaches the single ventricle, which pumps it to the body. Without a dedicated pump, lung flow depends on pressure differences, with breathing helping. That flow is less directly powered; pressure can rise in the veins, and exercise may be harder. So veins connect to the lung arteries, while the single ventricle pumps to your body.