Читать книгу Manual of Equine Anesthesia and Analgesia - Группа авторов - Страница 85

 Ventricular pressure rapidly drops below the pressure in the aorta and pulmonary artery, causing a reversal of the direction of blood flow and closure of the semilunar valves.This produces the high‐frequency second heart sound (S2).In horses, the pulmonary valve may close either slightly after or slightly before the aortic valve, resulting in an audible “splitting” of S2. This splitting is normal but can be dramatic in horses with pulmonary disease.Along with aortic recoil, valve closure produces the incisura of the arterial pressure curve.

Comment: The volume of blood ejected during systole is called SV, and the ratio of the SV to the end‐diastolic volume is the ejection fraction, which is a commonly used measure of systolic function.