Sonomicrometer method Pressure-volume loop experiments
assortment of sonomicrometer crystals ventricular volume computed directly (either in micro-liters or milli-liters) combining axial length measurements in standard spherical or ellipsoidal volume equations: v o l u m e = 4 3 × π × r 3 {\displaystyle volume={\frac {4}{3}}\times \pi \times r^{3}} (for single-axis measurement) v o l u m e = π 6 × l 1 × l 2 2 {\displaystyle volume={\frac {\pi }{6}}\times l_{1}\times l_{2}^{2}}...