Physiologic correlates of echocardiographic pulmonary valve motion in diastole.
It has been shown that the echographic motion of the posterior aortic wall in diastole is closely related to the underlying left atrial events, possibly due to the anatomical proximity of the two structures. We observed that the pulmonary artery shares a similar close anatomical relationship with the left atrium. The present study in 55 consecutive patients with adequate echocardiographic recordings of the aortic root and the pulmonary valve demonstrates that the diastolic waveforms of the pulmonary valve and the posterior aortic wall are nearly identical in early diastole. The pulmonary valve e-f slope correlated with the posterior aortic wall O-R slope (r = 0.95) and the S2-f interval (second heart sound to f on the pulmonary valve) correlated closely with the S2-R interval (second heart sound to R on the posterior aortic root) (r = 0.94)). No significant correlation was found between the pulmonary valve e-f slope and the pulmonary artery pressures. The presence and amplitude of the maximum "a dip," on the other hand, correlated with the presence of pulmonary hypertension, with some notable exceptions. In addition, the "a dip" on the pulmonary valve and the depth of the A wave on the posterior aortic wall were significantly correlated (r = 0.85). It appears that the "a dip" on the pulmonary valve is influenced by dual mechanisms: pressure differences between the pulmonary artery and the right ventricle in late diastole and the left atrial events. Thus, the early diastolic waveform of the pulmonary valve, like the posterior aortic wall waveform, may primarily reflect underlying left atrial events and is not a measure of pulmonary artery pressure. The late diastolic waveform "a dip" has a dual mechanism, related in part to the underlying left atrial events, and also reflecting the instantaneous pressure differences across the pulmonary valve following atrial systole.
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