Subclinical Left Ventricular Dysfunction in Preeclamptic Women With Preserved Left Ventricular Ejection Fraction A 2D Speckle-Tracking Imaging Study

Preeclampsia is a common hypertensive disorder of pregnancy. It is associated with both immediate, as well as long-term postpartum morbidity and mortality due to cardiac-related issues.1, 2 Even in clinically asymptomatic patients, subtle echocardiographic changes in left ventricular function have been observed in preeclampsia.3 Of the conventional echocardiographic indices, ejection fraction remains relatively preserved until later in the course of the disease process, making it less useful as a screening tool to follow patients over time.3 For this reason, the current assessment of pregnancy-related changes in myocardial function is based on either two-dimensional linear and volumetric chamber quantifications or Doppler indices of diastolic function.4 The availability of more sensitive and sophisticated non-invasive techniques may enhance our understanding of global ventricular function in the women with preeclampsia. Speckle tracking is a recently developed echocardiographic technique that analyzes the degree of myocardial deformation, known as strain, throughout the cardiac cycle. Speckle tracking, is obtained, by an automated measurement of the distance between speckles, in a specific ventricular segment in a two-dimensional echocardiographic image. Speckles are created by the irregular reflection of ultrasound that can be tracked throughout the cardiac cycle. Because, it is based on tracking the course of a speckle of the image over time in relation to its original location it is angle-independent and is less prone to operator-related measurement errors. Speckle tracking allows for the measurement of longitudinal, radial and circumferential strain and these have been used to prognosticate changes in left ventricular function and geometry.5–8 Strain is a parameter representing deformation of an object, relative to its original shape, and is expressed as a percentage change from the original dimension. Strain using speckle tracking is calculated by assessing the differences in distance and velocity of the speckle during the cardiac cycle. Positive values reflect lengthening, negative values reflect contraction. Cardiac Myofibrils can be oriented in the radial, circumferential and longitudinal plane, giving them a helical nature. In contrast with left ventricular ejection fraction, which is a measure of global function, strain with speckle tracking measures both regional and global function and also identifies the myocyte group that is affected. Moreover, the calculation for left ventricular ejection fraction includes geometric assumptions that speckle tracking does not. In this study we examined changes in myocardial strain as measured by speckle-tracking echocardiography in women with preeclampsia, women with nonproteinuric hypertension and women without a hypertensive disorder. We hypothesized that global left systolic strain measures would prove more sensitive than conventional left ventricular ejection fraction in detecting early changes in systolic left ventricular function manifesting as subclinical disease prior to overt progression.