Determination of systolic intervals utilizing the carotid first derivative

Left ventricular ejection time (LVET) is a useful parameter of cardiac function which may be difficult to measure in restless, dyspneic, and uncooperative patients. Certain well-defined points of the first time derivative of the carotid displacement pulse are suitable to determine LVET and appear more reliable than the corresponding points in the carotid pulse itself under technically adverse situations. Systolic time intervals thus obtained correlate well with those determined by utilizing the undifferentiated carotid pulse wave. Thus the carotid first time derivative (dD/dt) serves as a more versatile and convenient method for such measurements, because of greater freedom from motion artifact and better definition of points.