The heartbeat rate is a vital patient measurement. The following procedure isused to obtain this measurement. Whiledeflating a cuff that is attached to a person’sarm, slight variations in the overall cuffpressure may be detected (Figure 1-2b).This variation in the cuff’s pressure is due tothe pressure change from blood circulation.This variation is amplified through a filterdesigned at 1 Hz, and set to an offset.This new signal is the heartbeat signal.