This Article Abstract Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Chen, C.-H. Articles by Kass, D. A. Search for Related Content PubMed PubMed Citation Articles by Chen, C.-H. Articles by Kass, D. A.

Noninvasive single-beat determination of left ventricular end-systolic elastance in humans

^a Division of Cardiology, Taipei Veterans General Hospital, Taipei, Taiwan, R.O.C. Taiwan
^b National Yang-Ming University, Taipei, Taiwan, R.O.C. Taiwan
^c Division of Cardiology, Department of Internal Medicine, The Johns Hopkins Medical Institutions, Baltimore, Maryland, USA

View larger version (21K): [in a new window]   Figure 1 Estimation of normalized time-varying elastance value at the onset of ejection for individual subjects. The estimate is based on the group-averaged value (14), resting ejection fraction and the ratio of diastolic to systolic arterial pressure (equation 2). Plot shows correlation between predicted normalized left ventricular elastance at the onset of ejection (ENd) and directly measured value.

View larger version (45K): [in a new window]   Figure 2 (A) Invasive pressure-volume loops and analysis used to derive (Ees). Multiple beats are recorded before and during transient obstruction of the inferior vena cava. (B) Noninvasive assessment of (Ees(sb)) displayed in pressure-volume plane from the same example. Two sets of (volume, pressure) data points are measured and used to predict Ees(sb). The dotted area represents a schematic pressure-volume loop based on these points. From these data, Ees(sb) is estimated using equation 4. (C) Example of pressure-volume data at rest and after dobutamine stimulation. (D) Corresponding noninvasive Ees(sb) for the same example displayed in C. Darkened areas are schematic loops from the two points. Pd = diastolic arterial pressure at the onset of ejection; Pes = left ventricular end-systolic pressure; SV = stroke volume; Ved = left ventricular end-diastolic pressure; Ves = left ventricular end-systolic volume.

View larger version (27K): [in a new window]   Figure 3 (A) Linear regression (solid line) and 95% confidence intervals (dotted lines) comparing noninvasive left ventricular elastance at end-systole derived by single-beat technique (Ees(sb)) and invasive (multi-beat) left ventricular end-systolic elastance (Ees) at baseline for 43 subjects. (B) Bland-Altman plot of Ees(sb)-Ees difference versus mean value. Mean and 99% confidence interval of the mean difference is shown. (C and D) Same analysis as in A and B but including data after dobutamine stimulation, which expanded the range of Ees comparisons. The correlation between measurements is very good and falls along the line of identity.

View larger version (22K): [in a new window]   Figure 4 Paired comparison of change in left ventricular end-systolic elastance (Ees) induced by dobutamine determined by noninvasive estimation versus the directly assessed value derived from invasive pressure-volume loops. The noninvasive method provided a good estimate of Ees (n = 29, r = 0.88, p < 0.0001, with a regression slope and intercept that were not statistically different from 1.0 and 0, respectively. Ees(sb) = change in left ventricular end-systolic elastance by single-beat technique.

View larger version (17K): [in a new window]   Figure 5 Comparison of resting end-systolic pressure/volume ratio (Pes/Ves) as an estimate of elastance to directly measured left ventricular end-systolic elastance (Ees) by invasive analysis. Unlike Ees(sb) (Fig. 3B), the pressure-volume ratio consistently overestimated directly measured Ees, and the regression had a non-zero bias (2.2 mm Hg/ml) as demonstrated in the lower Bland-Altman plot.