The Cardiovascular Engine
Your heart beats approximately 100,000 times per day, pumping about 7,000 liters of blood through a network of vessels that, laid end to end, would stretch over 100,000 kilometers. The cardiovascular system is a masterpiece of biological engineering — a pressure-driven fluid circuit that delivers oxygen and nutrients to every cell while removing waste products. This simulation models its core hemodynamics.
Cardiac Output and Blood Pressure
The two fundamental variables of cardiovascular function are cardiac output (CO = heart rate × stroke volume) and blood pressure (MAP = CO × total peripheral resistance). These are linked by the cardiovascular equivalent of Ohm's law: pressure equals flow times resistance. The body continuously adjusts heart rate, stroke volume, and vascular tone to maintain adequate perfusion of vital organs.
The Pressure Waveform
Each heartbeat generates a characteristic pressure wave that travels through the arterial system. The systolic peak occurs when the left ventricle contracts, ejecting 60-80 mL of blood into the aorta. The diastolic trough represents the minimum pressure between beats, maintained by elastic recoil of the arterial walls. The dicrotic notch (a small bump on the downslope) marks the closing of the aortic valve. Watch the animated waveform respond in real-time as you change heart rate and stroke volume.
Clinical Significance
Hypertension (high blood pressure) affects over 1 billion people worldwide and is the leading modifiable risk factor for cardiovascular disease. This simulation helps visualize why: increasing peripheral resistance or cardiac output directly raises MAP. Beta-blockers reduce heart rate and stroke volume; vasodilators reduce peripheral resistance; diuretics reduce blood volume. Understanding these hemodynamic relationships is fundamental to managing the world's most common chronic disease.