Noninvasive ambulatory monitoring of physiologic data: recording systolic time intervals

Adding physiologic data to ambulatory electrocardiographic monitoring data yields information with great potential for diagnostic and therapeutic use. The ear densitogram's stability, demonstrated during exercise and under laboratory conditions, indicates its applicability to ambulatory monitoring as a source of systolic time intervals. Circuitry has been developed to feed the output of an ear densitogram pickup into one channel of a two-channel Holter monitor. Baseline studies in different postures are used to establish pulse transmission time, which permits the ear densitogram pulse to be used as a delayed aortic pulse in measuring systolic time interval. Feasibility and field studies have shown that systolic time intervals can be precisely determined by this method.