Ten subjects with normal hemodynamics were studied during elective cardiac catheterization with right and left heart multisensor micromanometry to assess hemodynamic responses to the Mueller maneuver. Simultaneous right and left circulatory hemodynamics and left ventricular, pulmonary arterial, and aortic pressures were recorded, in addition to pulmonary arterial and aortic flow velocities. Steady-state cardiac outputs were determined by thermal dilution. Aortic systolic and mean pressures were not significantly changed during the Mueller maneuver, in contrast to a lower diastolic (p = .019) and higher pulse pressure (p = .016). Mean right atrial pressure (± SE) decreased from 7 1 to -17 + 4 mm Hg (p = .0002) and the right atrial "x" descent was markedly accentuated. Left ventricular end-diastolic pressure decreased from 12 + 4 to -3 ± 13 mm Hg (p = .0025). Systemic vascular resistance and left ventricular peak positive dP/dt were increased during the Mueller maneuver (p < .02), cardiac output and stroke volume were reduced (p < .05), and there was no significant change in heart rate. Right and left peak flow velocities showed a trend toward a bilateral decrease (right, p = .054; left, p > .1), and times to peak flow velocity were increased in the pulmonary artery (p = .007) and reduced in the aortic root (p = .03). Normal subjects were studied separately by pulsed Doppler echocardiography. During the sustained Mueller maneuver, the internal jugular and right ventricular dimensions decreased, and superior vena cava Doppler flow was reduced. These data demonstrate reduced flow through the right and left heart chambers during a sustained Mueller maneuver in humans, in contrast to prior theory and animal data suggesting that right heart flow is increased during sustained forced inspiratory effort.

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