Longitudinal Assessment of Left and Right Myocardial Function in Preterm Infants Using Strain and Strain Rate Imaging

Area of Science:

• Neonatal cardiology
• Pediatric cardiovascular research
• Fetal and neonatal medicine

Background:

• Limited longitudinal data exist on left ventricular (LV) and right ventricular (RV) function in extremely preterm infants (<29 weeks gestation).
• Understanding cardiac adaptation in this vulnerable population is crucial for clinical management.

Purpose of the Study:

• To describe longitudinal changes in LV and RV myocardial function using tissue Doppler-derived strain and strain rates.
• To assess the influence of systemic vascular resistance (SVR), patent ductus arteriosus (PDA), and chronic lung disease (CLD) on cardiac function from birth to 36 weeks postmenstrual age (PMA).

Main Methods:

• Echocardiographic assessments including basal longitudinal strain (BLS), systolic (SRs), early (SRe), and late (SRa) diastolic strain rates were performed at multiple time points (days 1, 2, 5-7, and 36 weeks PMA).
• Correlations with SVR, PDA severity, and the presence of CLD were analyzed.

Main Results:

• In 105 extremely preterm infants (median gestation 27.1 weeks), myocardial function generally improved over time.
• Day 1: Weak negative correlations were observed between SVR and LV BLS/septal BLS, and LV SRe.
• Days 5-7: Infants with PDA >1.5 mm showed higher LV BLS. At 36 weeks PMA, CLD was associated with lower RV BLS and RV SRa.

Conclusions:

• Myocardial function exhibits significant longitudinal development in preterm infants.
• Left heart strain appears relatively insensitive to acute changes in preload and afterload.
• Chronic lung disease is associated with impaired right ventricular function in extremely preterm infants.