Determination of Systolic Time Intervals from the First Derivative of the Indirect Brachial Arterial Pulse

Technical difficulties occasionally preclude adequate recording of the indirect carotid pulsations needed for measuring the systolic time intervals by the conventional method. Accordingly, in 81 subjects with a wide spectrum of heart diseases, an alternative method was tested based on substituting the first time derivative of the indirect brachial arterial pulse for the carotid pulse. The observed differences between systolic time intervals measured by the two methods were small enough, and their correlation coefficients high enough, to inspire confidence in the use of the proposed method as an alternative way for determining systolic time intervals.