Ventricular Tachycardia and Ventricular Fibrillation

Electrical wildfire in the heart's wiring

Imagine the heart's electrical system as a choreographed relay race where one runner (the SA node) triggers the next, and so on, in perfect sequence around the ventricles. Normally, the signal passes through the AV node (like a mandatory slow zone) so runners finish filling before the next leg starts. But when scar tissue or low potassium damages the track, a runner can loop backward and collide with the runner behind them, creating a chaotic pile-up that keeps repeating faster and faster (that's reentry creating VT). Or, if the whole stadium of runners suddenly starts sprinting in random directions with no starting gun—that's VF, total chaos with no forward progress. Meanwhile, the spectators (your organs) need blood flow like fans need to get in their seats; if the relay stops moving, everything backs up and suffocates. CPR is like manually pushing the runners along the track to keep some flow going, and the defibrillator shock is like a whistle that freezes everyone so the SA node can restart the race cleanly.