.... Images obtained at five slice positions from 2 mm anterior to 2 mm posterior to the AV valve. (B) Area changes of the ventricles during two cardiac cycles. The ventricle areas were normalized by the area at end-diastole. All of the measurements were conducted within 4.5 h of placing the mussel...

... peristaltically rear-to-front(`peristaltic heart'), followed by nearly synchronous front-to-rear constrictions in the contralateral heart segments (`synchronous heart'). Using optical recordings from intact leeches, we now characterize the hemodynamic properties of the cardiac cycle of individual heart segments...

..., compared with those in the right aorta or pulmonary arteries, and the foramen of Panizza has very little significance in the cardiac cycle. If the systemic blood pressures are low, the second stage of systole in the right ventricle gives rise to pressures that are higher than those in the left aorta...