Gestational changes in left ventricular myocardial contractile function: new insights from two-dimensional speckle...

Area of Science:

• Cardiology
• Physiology
• Obstetrics

Background:

• Pregnancy induces significant hormonal and hemodynamic changes affecting cardiac function.
• The precise impact on left ventricular (LV) myocardial mechanics during pregnancy and labor remains incompletely understood.

Purpose of the Study:

• To investigate the effects of pregnancy and labor on LV myocardial mechanics.
• To assess changes in global longitudinal, circumferential, and radial strain using speckle tracking echocardiography (STE).

Main Methods:

• A prospective, longitudinal study involving 35 pregnant women and 20 age-matched controls.
• Serial echocardiographic evaluations including 2D STE were performed throughout pregnancy and at labor.
• Measurements of global LV longitudinal strain (GLS), circumferential strain (GCS), and radial strain (GRS) were analyzed.

Main Results:

• Pregnancy led to increased heart rate, blood pressure, cardiac output, and LV stroke-work.
• LV end-diastolic and end-systolic volumes increased, while ejection fraction remained stable.
• GLS and GCS were reduced from the first trimester, persisting through labor.
• GRS increased during pregnancy, peaking in the second trimester.

Conclusions:

• Pregnancy-induced alterations in cardiac loading conditions are met by counterbalancing changes in myocardial mechanics.
• Reduced longitudinal and circumferential strain with increased radial strain maintain LV ejection performance.
• These adaptive myocardial changes enable the maternal heart to cope with the physiological demands of pregnancy and labor.