Quantitative Evaluation of Left Ventricle Performance from Two Dimensional Echo Images

Accuracy of cardiac function and volume status estimates using the bedside echocardiographic assessment in trauma/critical care

BACKGROUND

Critically ill patients often require invasive monitoring to evaluate and optimize cardiac function and preload. With questionable outcomes associated with pulmonary artery catheters (PACs), some have evaluated the role of less invasive monitors. We hypothesized that the Bedside Echocardiographic Assessment in Trauma (BEAT) examination would generate cardiac index (CI) and central venous pressure (CVP) estimates that correlate with that of a PAC.

METHODS

BEAT was performed on all SICU patients with a PAC in place. Prospective data included stroke volume and the inferior vena cava (IVC) diameter. The CI was calculated and correlated with that from the PAC. Each CI was then categorized as low, normal, or high. The IVC diameter was used to estimate the CVP. The association between the BEAT and PAC estimates of CI and CVP was evaluated using chi.

RESULTS

Eighty-five BEAT examinations were performed, 57% on trauma and 37% on general surgery patients. Fifty-nine percent of the CI examinations and 97% of the IVC examinations contained quality images. Of these, the overall correlation coefficient was 0.70 (p < 0.0001). When CI was categorized, there was a significant association between the BEAT and PAC (p = 0.021). There was a significant association between the CVP estimate from the BEAT examination and the PAC (p = 0.031).

CONCLUSION

Our data show a significant correlation between the CI and CVP estimates obtained from the BEAT examination and that from a PAC. BEAT provides a noninvasive method of evaluating cardiac function and volume status. Bedside echocardiography is teachable and should become a part of future critical care curricula.

Is echo-determined left ventricular geometry associated with ventricular filling and midwall shortening in hypertensive ventricular hypertrophy?

BACKGROUND

The correlation between left ventricular (LV) geometry, mass, diastolic function, and midwall fractional shortening (MFS) in hypertensive patients with left ventricular hypertrophy (LVH) is not well established owing to limited diffusion of MFS evaluation. The aim of the study was to evaluate this correlation in 1887 consecutive hypertensive patients, all affected by LVH (mean age 66 years, 924 males), with LV ejection fraction (LVEF) >45% for early detection of ventricular dysfunction rather than LVEF and diastolic function impairment.

METHODS AND RESULTS

All patients underwent M-B mode echocardiography and PW-Doppler evaluation. LV geometry and mass were compared with Doppler-determined mitral flow and tissue velocities. LV geometry was eccentric (E) for 1018 subjects (53.9%) and concentric (C) for 869 (46.1%). There was no difference concerning LV diastolic dysfunction (P: n.s.) between 576 (30.6%) of the ELVH and 368 (19.4%) of the CLVH patients. The following parameters showed significant statistical differences: LV MFS impairment (P < 0.01) between 86 (4.6%) of the ELVH and 177 (9.4%) of the CLVH patients. LV MFS impairment rate was higher in 171 patients without LV diastolic dysfunction (9.1%), than in 92 patients affected (4.9%, P < 0.02). In CLVH patients, a higher prevalence of LV MFS impairment was observed in 143 without LV diastolic dysfunction (7.6%), than in 34 patients affected (1.8%, P < 0.01). In ELVH patients, a lower prevalence of LV MFS impairment was observed in 28 without diastolic dysfunction (1.5%), than in 58 patients affected (3.1%, P < 0,03).

CONCLUSION

Midwall LV impairment, an independent predictor of cardiac death and morbidity in hypertensive patients, can allow early identification of patients with LV dysfunction even when LVEF or assessment of diastolic function are normal. LV MFS impairment rate is higher in CLVH patients, and even higher when considering only those CLVH patients with no diastolic dysfunction. These results suggest that the ventricular dysfunction with normal LVEF is not always due to diastolic dysfunction, but often to systolic dysfunction as assessed by MFS impairment, an important early sign of ventricular dysfunction in hypertensive patients, even when diastolic function is normal.