Effects of posture on heart rate and systolic time intervals in normal man

The Valsalva maneuver is a commonly practiced technique for the assessment of cardiac function. 1–5 Elisberg 2 found that heart rate response reliably reflects the hemodynamic change during the Valsalva maneuver. However, because many patients with congestive heart failure have an impaired response to catecholamine stimulation, heart rate response does not always reflect the change in left ventricular filling. Ear densitography is an ideal noninvasive technique to evaluate beat-to-beat hemodynamic change during the Valsalva maneuver, because it is reported to track the aortic pressure pulse pattern very closely during strain and release. 5 Since the Valsalva maneuver is frequently performed during daily activity, it is desirable to assess the cardiac response to the Valsalva maneuver in the more natural upright position. The present investigation evaluates the time course changes of heart rate and systolic time intervals during the Valsalva maneuver in the sitting and supine positions.