Physiological adaptation of the left ventricle during the second and third trimesters of a healthy pregnancy: a speckle tracking echocardiography study.

BACKGROUND: During a healthy pregnancy women experience cardiovascular and hemodynamic changes and normal ranges of left ventricular (LV) function on two-dimensional speckle tracking echocardiography (STE) are not well defined. The aim of this study was to describe the cardiovascular changes that occur during the second and third trimesters of a healthy pregnancy using STE.

METHODS: Pregnant subjects were enrolled retrospectively if they underwent a transthoracic echocardiography (TTE) between 2011-2014. Subjects with abnormal TTE findings, hypertension, diabetes, preeclampsia, prior cardiac surgery, poor imaging quality or in the 1st trimester were excluded. A total of 74 pregnant subjects were categorized into the 2nd or 3rd trimesters. Twenty-one healthy age-matched females were selected as a control group.

RESULTS: The heart undergoes extensive remodeling during pregnancy with increased LV septal thickness, posterior wall thickness, cavity size and mass (p=0.045, p=0.002, p<0.001, p=0.018, respectively). However, myocardial mechanical function measured by: global longitudinal strain, radial strain, circumferential strain, systolic and diastolic global longitudinal strain rate (GLSR), global radial strain rate (GRSR) and global circumferential strain rate, remains preserved. Only time to peak strain rate corrected for heart rate for diastolic GRSR and diastolic GLSR were significantly increased in the third trimester (p=0.016 for both).

CONCLUSION: Despite extensive heart remodeling, many STE derived parameters of LV function in healthy pregnant women remain unchanged and valid for women in the 2nd and 3rd trimester. Future studies investigating early detection of pregnancy related heart disease can refer to these parameters as reference ranges.