MATERNAL LEFT VENTRICULAR ADAPTATION IN TWIN PREGNANCY

Abstract

Objective: During pregnancy, a maternal left ventricular (LV) remodeling occurs to face significant hemodynamic changes. Although twin pregnancy can require greater modifications than in singleton, limited data are currently available. The aim of the study was to longitudinally investigate maternal changes of LV function and compliance in twin pregnancy. Design and method: 35 uncomplicated twin pregnancy women underwent transthoracic echocardiography at first (T1, 10-15 weeks) and third trimester (T3, 30-35 weeks) of gestation. Left atrial (LA) and LV dimensions, LV volumes, systolic and diastolic function were measured, LV mass was calculated. Speckle-tracking imaging was used to evaluate global longitudinal strain (GLS). Non-invasive pressure-volume curves (PV loops) were reconstructed using a dedicated software. Results: Maternal LA and LV dimensions, LV volumes and mass increased from T1 to T3. Ejection fraction and GLS showed no changes between visits. Assessment of diastolic function (at pulsed wave Doppler and tissue Doppler) showed no changes in E/A ratio, while E/e’ ratio was higher at T3. At PV loops analysis, ventricular-arterial coupling (VAC) was stable due to the reduction of both LV end-systolic elastance (Ees) and arterial elastance (Ea). An increase in stroke work was observed. The increase in LV end-diastolic volumes from T1 to T3 with no changes in LV end-diastolic filling pressure suggested enhanced LV cavity compliance (rightward shift of the end-diastolic pressure-volume relationship, EDPVR). Conclusions: Maternal heart in uncomplicated twin pregnancy adapts to the increased hemodynamic load with an increase in stroke work and enhancement of LV volumes without altering ventricular filling pressure.