Fig 14Heart · one beatHover ↔ time in the beat0.00 s · isovol. contraction · LV 8 / Ao 79 mmHg
Oxygenated blood (left heart), 1 dot = 5 mL; aortic pressureVenous blood (right heart)Valve leafletsLV pressure (catheter tip), black on the monitorThe back half of an adult human heart cut in the frontal plane, through all four chambers (ruler: 1 tick = 5 mm). The outflow tracts and great vessels, which really lie in front of the atria, are folded into the same section so all four valves show at once. One beat at 75 per minute, from a lumped model (time-varying elastance chambers, pressure-driven valves, Windkessel arteries): the left ventricle fills to 122 mL and ejects 74 mL (ejection fraction 60%), peaking at 122 mmHg against an aortic pressure of 122/79; the right ventricle moves the same volume at 22/2 mmHg. Each valve opens only when the pressure behind it is higher than the pressure ahead: the mitral and tricuspid close as the ventricles start to squeeze, the aortic and pulmonary open once ventricular pressure passes arterial pressure and close as it falls back. The apex stays still while the valve plane slides about 14 mm (mitral) and 21 mm (tricuspid) toward it, so the atria refill while the ventricles empty. The dual-sensor catheter reads LV pressure at its pigtail tip and aortic pressure 5 cm back; the monitor sweeps both with left-atrial pressure dashed. The tour plays the beat 4× slower than life; hover to scrub through it.