[Transesophageal echocardiography for determining left-ventricular end-diastolic myocardial tension]

Left ventricular end-diastolic wall stress (EDWS) ist an index for left ventricular preload. Utilising transoesophageal echocardiography, left ventricular dimensions can be obtained by two-dimensional (2d-) as well as M-Mode measurements, and each can be combined with pulmonary capillary wedge pressure (PCWP) for the calculation of EDWS. In the present examination, both methods were compared with regard to their technical accomplishment and reproducibility under clinical conditions.

EDWS was obtained in 24 ventilated patients by 2d-echocardiography (2d-EDWS) and M-mode-echocardiography (M-EDWS) before and after a change in PCWP by 3mmHg. In 12 patients, volume therapy with hydroxyethylstarch (HAES) was started when PCWP < 11 mmHg; in another 12 patients, continuous intravenous administration of nitroglycerine was begun, when PCWP > 14 mmHg. 2d-EDWS and M-EDWS were compared and their relation to thermodilution stroke volume and stroke work index analysed.

2d-EDWS and M-EDWS correlated well in both groups (HAES: r = 0.91; NITRO: r = 0.93), with M-EDWS being systematically lower than 2d-EDWS. The relative difference between 2d-EDWS and M-EDWS, and their mean value--calculated as the mean per cent error--was 11.2%. Directional changes in preload were reflected in all patients by 2d-EDWS and M-EDWS in accordance. Both correlated better with stroke volume and stroke work index than PCWP. Determination of 2d-EDWS showed better inter- and intraobserver variability in the echocardiographic measurements.

With regard to direction and quantity, changes of preload as seen with echocardiographic EDWS were according reflected by the 2d- and the M-mode technique. Determination of 2d-EDWS compared to M-EDWS was superior in reproducibility and more useful for the estimation of stroke volume changes.