Real-time three-dimensional echocardiography integrated with diagnostic catheterization to derive left ventricular pressure–volume relations: a feasibility study

We investigated the left ventricular (LV) myocardial contractility index-Emax using transoesophageal real-time three-dimensional echocardiography (RT3DE) combined with catheterization.

Transoesophageal RT3DE (single beat, X7-2 X matrix, iE33, Philips) was used to obtain real-time LV volumes in pigs. Volumes were integrated with LV pressures from conductance catheterization (CC) with micromanometer 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. Six pigs were studied. At baseline, the mean ± SD (mmHg/mL) values were Emax-CC 1.86 ± 1.1 and Emax-RT3DE 1.78 ± 1.2 (P = 0.502). 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.

Emax can be determined from RT3DE integrated with catheterization-derived pressures. RT3DE is a promising method for enhancing clinical applicability of pressure–volume relations for assessment of myocardial contractility.