Stroke volume calculated from the mitral valve echogram in patients with and without ventricular dyssynergy.

Abstract

A formula was derived for calculating mitral valve stroke volume (MVSV) using the rate of mitral valve (MV) opening (DE slope on the MV echogram), the vertical disease between the mitral leaflet echoes early in diastole (EE), the electrocardiographic PR interval and heart rate. The formula was tested prospectively on 80 consecutive patients from whom 95 simultaneous MV echograms and either thermodilution (45) or Fick (50) cardiac outputs were obtained. Sixteen patients were normal; 54 had coronary artery disease; three had cardiomyopathy; and seven had nonrheumatic mitral regurgitation (MR). Linear regression for stroke volume was r = 0.90, SEE +/- 6, and for cardiac output r = 0.83, SEE +/- 0.5 liter for the 73 patients without MR. The presence or absence of ventricular dyssynergy did not alter statistical findings. MVSV consistently overestimated forward stroke volume for the seven patients with MR. This study shows that the MV echogram provides an accurate, widely applicable method for calculating MVSV.

Functional mitral stenosis after surgical annuloplasty for ischemic mitral regurgitation: Importance of subvalvular tethering in the mechanism and dynamic deterioration during exertion

“…Decreased mitral leaflet opening in patients with LV dys-function7 has been widely attributed to decreased transmitral flow volume. However, mitral leaflet opening is independent of inflow volume,8,9 and reduced leaflet opening in LV dys-function reflects diastolic leaflet restriction caused by subvalvular tethering 9,10.…”

“…Therefore, systolic leaflet closure is restricted in these patients. Reduced diastolic leaflet opening in patients with LV dysfunction has also been observed and was long interpreted as reflecting a reduction in mitral inflow volume 7. However, mitral leaflet opening is independent of inflow volume,8,9 and reduced leaflet opening in LV dysfunction is now understood as reflecting a restriction in diastolic leaflet mobility by subvalvular tethering (Figure 1, A , middle) 9,10.…”

Urinary Calcium Excretion at Extremes of Sodium Intake in Normal Man

“…The same manometers, cuffs and observers were uti lized for these measurements throughout the study. Cardiac index, stroke index, and end-systolic left ventricular volume were measured noninvasively on the final day at each level of sodium intake by means of echocardiography [22][23][24], Daily 24-hour urine collections were obtained for the determina tion of sodium, potassium, calcium, creatinine, norepinephrine and cAMP concentrations. Acetic acid was used as the preservative to protect against urinary norepinephrine loss during storage.…”

Asymmetric Septal Hypertrophy in Uremic-Normotensive Patients on Regular Hemodialysis

“…Left ventricular (LV) chamber dimensions and the thickness of interventricular septum (IVST) and the posterior wall (PWT) were measured at the level of the chordae tendineae, both in end-di astole and in end-systole, according to the standard convention of the European Association of Cardiology [20], The LV performance was assessed by the following parameters: (I) systolic percentage of thickening of interventricular septum (A-IVST%) and of the poste rior wall (A-PWT%); (2) fractional shortening of LV (FS%): (3) normalized mean circumferential shortening (mean Vcf): (4) LV end-diastolic volume (LVEDV), according to the Teicholz formula [21]; (5) stroke volume (SV), calculated by an average of the values obtained both with Rasmussen [22] and Teicholz formulas: the mean difference between the two measurements was 4.9 ± 3.0 cm3; (6) cardiac output was calculated by multiplying the SV by the heart rate (HR), derived from the ECG recorded simultaneously with the echocardiogram; (7) cardiac index (Cl) was calculated by dividing the cardiac output by the body surface area. The ejection fraction (EP/o) was obtained by dividing SV by LVEDV; (8) arterial blood pressure (BP) was measured using a mercury sphygmomanometer on the arm without A-V fistula.…”