Pressure Flow Studies in Patients Having a Pressor Response to the Valsalva Maneuver

Blood pressure and flow were measured in the ascending aorta by means of the pressure-gradient technique in five patients with congestive heart failure manifesting a pressor response to the Valsalva maneuver. Beat-to-beat changes in stroke volume, blood pressure, pulse pressure, peak blood flow, duration of systole, duration of ejection, and heart rate were calculated. Stroke volume and blood pressure rose with the onset of straining; blood pressure rose slightly further as stroke volume fell to below control levels at the end of the straining period. Pulse pressure, peak blood flow, and duration of ejection tended to follow stroke volume. Heart rate was unchanged throughout. All parameters returned toward control after release of the strain. Additional Indexing Words: Pulsus alternans Congestive heart failure THE ABNORMAL circulatory response to the Valsalva maneuver, which occurs in some patients having heart failure, has been recognized for over 20 years,1 ' 2 yet despite the continued interest of circulatory physiologists, its mechanism remains incom-pletely understood. The abnormal response is characterized either by an unchanged or an increased pulse pressure during straining, and by either a "square wave " pattern in the arterial pressure tracing, or by a fall in the diastolic blood pressure following release of the strain. There is no associated change in the heart rate. It has been suggested that the increase in pulse pressure during the strain-ing phase in some patients may be due to an increased stroke volume.3 However, observa