Combination of real time three-dimensional echocardiography with diagnostic catheterization to derive left ventricular pressure-volume relations

Aims: The aim of this study was to investigate the left ventricular (LV) myocardial contractility index- Emax using transesophageal real time three-dimensional echocardiography (RT3DE) combined with catheterization. Methods: Transesophageal RT3DE (single beat, X7-2 × matrix, iE33, Philips) was used to obtain real time LV volumes in pigs. Volumes were integrated with LV pressures from conductance catheterization (CC) to create RT3DE pressure-volume relations. At the same time, CC was used for measuring conventional pressure-volume relations that served as reference. The slope Emax was determined from RT3DE and CC end-systolic pressure-volume relations. All measurements were made at rest and during dobutamine infusion. Results: In six pigs, the mean ± SD (mmHg/mL) values were Emax- CC 1.86 ± 1.1 and Emax-RT3DE 1.78 ± 1.2 (P = 0.502) at baseline. On dobutamine, mean Emax-CC was 3.43 ± 1.5 and Emax-RT3DE 3.60 ± 1.23 (P = 0.171). Bland-Altman analysis showed good agreements between the RT3DE- and CC-derived Emax for measurements performed at baseline and on dobutamine. Conclusions: Emax can be determined from RT3DE integrated with catheterizationderived pressures. RT3DE is a promising method for enhancing clinical applicability of pressure-volume relations for assessment of myocardial contractility.