We investigated whether the left ventricular filling profile, defined as the early to late diastolic left ventricular filling volume ratio, during the preceding control beats actually affects the pulse pressure during a ventricular premature contraction (PVC). Twenty patients underwent invasive electrophysiological study for sinus bradycardia. VPCs with various coupling intervals were induced by right ventricular electrical stimulation, and the mitral filling flow velocity by pulsed Doppler echocardiography, the femoral arterial pressure curve and the electrocardiogram were simultaneously recorded. The early to late diastolic velocity-time integral ratio (Ei/Ai ratio) of the mitral filling flow velocity during the control beats which preceded the VPC was measured as an index characterizing left ventricular filling profile. The coupling interval of each VPC and the extrasystolic beat pulse pressure were measured. The ratio of the extrasystolic beat pulse pressure to the control beat pulse pressure was expressed in % (% extrasystolic beat pulse pressure). The correlation between the coupling interval and the % extrasystolic beat pulse pressure was investigated. Coupling intervals of 0.80, 0.70, 0.60, 0.50, and 0.45 s were used. At a coupling interval of 0.80 or 0.45 s, the % extrasystolic beat pulse pressure showed no significant correlation with the Ei/Ai ratio. In contrast, the % extrasystolic beat pulse pressure with coupling intervals of 0.70, 0.60, and 0.50 s showed a significant positive correlation with the Ei/Ai ratio (r = 0.67, 0.74, and 0.66, P < 0.01, respectively). In addition to the prematurity and the site of origin of the VPCs, the left ventricular filling profile during the preceding control beats may significantly affect the height of the pulse pressure during extrasystoles with medium length coupling intervals.

Features of venousreturn in chronic pulmonarydiseases and factors determining such features were studied by analysis of respiration-related variation in the superior vena cava flow on pulsed Doppler echocardiography. Subjects of this study were 85 patients with chronic pulmonary diseases; 54 healthy subjects served as normal controls. In the healthy subjects, the velocity of the S and D waves increased during inspiration (type I pattern), and the velocity of the A wave increased during expiration. In the patients with pulmonary diseases, the pattern of the superior vena cava flow was either type I or type II (disappearance of the D wave or disappearance of both the D and S waves). The incidence of the type II pattern was significantly higher in the patients showing a reduction of both FEV10%and %VC. The respiration-related variation in the superior vena cava flow pattern was found to be determined by the pressure fall between right atrium and subclavian vein. A type II pattern was attributed to the elevation of right atrial pressure caused by positive pleural pressure. The velocity of the A wave increased during expiration, showing a good correlation with pulmonary vascular resistance. Venousreturn in the presence of chronic pulmonary disease was found to be affected by the type of ventilatory disturbance and intensity of pulmonaryvascular resistance.

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