Stable CAD and Chronic Angina

A Clogged Water Pipe During Peak Demand

Imagine a house's water pipes: normally, the main supply line delivers enough steady flow at rest to fill the toilet and kitchen sink. But when you turn on the shower, washing machine, and garden hose at the same time (peak demand), a narrow section of pipe — clogged with calcium deposits and rust (plaque) — cannot expand to let more water through. The pressure drops, the shower sputters, and you feel the system strain (angina pain). Turn off the extra faucets (rest or nitroglycerin) and the pressure normalizes because demand drops back down. The fixed blockage is still there, but it is no longer choking the supply. The danger: if that clogged section gets completely plugged by a clot of sediment (like a sudden clog in the kitchen), all water stops and the system fails catastrophically (heart attack). The whole system runs fine at idle, which is why the clog goes unnoticed until you demand peak performance — just like stable CAD feels fine until you climb stairs.