Two-dimensional echocardiography is useful for demonstrating abnormal contractility of human left ventricular papillary muscles. Papillary muscle contractility should be analyzed in each case to elucidate the mechanism of mitral regurgitation in patients with papillary muscle dysfunction.
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.
This study was designed to investigate whether the left ventricular filling profile during preceding control beats significantly affects the pulse deficit caused by ventricular premature contractions (VPCs). The study group consisted of 18 patients (10 men, eight women, 15-85 years old) who underwent electrophysiological catheterization because of sinus bradycardia. Using a temporary pacing lead inserted in the right ventricular apex, isolated VPCs with various coupling intervals were produced by electrical stimulation of the right ventricle. During the production of the VPCs, the mitral filling flow velocity using pulsed wave Doppler echocardiography, the femoral arterial pressure curve and the electrocardiogram were simultaneously recorded. The right ventricle was stimulated 800, 750, 700, 650, 600, 550, 500, 450 and 400 ms after the triggered control beat QRS complex. Pulse pressures during VPCs gradually decreased in relation to the shortening of the extrasystolic beat coupling interval. The longest coupling interval for each subject, which caused complete abolition of the pressure pulse during the VPC, was defined as the pulse deficit coupling interval. The early to late diastolic velocity-time integral ratio (Ei/Ai ratio) of the mitral filling flow velocity during the control beats which precede the VPC was obtained as an index expressing the left ventricular filling profile. The Ei/Ai ratio of the mitral filling flow velocity ranged from 0.7 to 4.5 (1.8 +/- 1.0). The pulse deficit coupling interval ranged from 440 to 640 ms (510 +/- 60 ms).(ABSTRACT TRUNCATED AT 250 WORDS)
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