When is systolic pressure recorded during a blood pressure measurement?

Systolic pressure is recorded at the point when the first sharp tapping sound is heard through a sphygmomanometer. This tapping, known as Korotkoff sounds, indicates that blood is beginning to flow through the artery after being temporarily occluded by the cuff. When the cuff pressure is gradually released, the first sound corresponds to the pressure in the artery when the heart is contracting, which is why this sound marks the systolic reading.

This methodology is based on the principle that the blood pressure in the arteries rises during heartbeats (systole) and falls during resting periods between beats (diastole). Identifying the first tapping sound accurately is crucial for determining the systolic blood pressure while ensuring the assessment reflects the patient's cardiovascular state at the moment the heart is actively pumping.