Age-dependent ventricular response to pressure overload. Considerations for the arterial switch operation

Area of Science:

• Pediatric Cardiology
• Cardiac Physiology
• Developmental Biology

Background:

• The arterial switch operation is a key intervention for D-transposition of the great arteries.
• Assessing left ventricular suitability for systemic workload is crucial for surgical success.
• Understanding age-dependent cardiac growth is essential for optimizing surgical timing and outcomes.

Purpose of the Study:

• To review age-dependent mechanisms of normal cardiac growth.
• To examine age-dependent mechanisms of pressure-induced left ventricular hypertrophy.
• To correlate these mechanisms with surgical strategies for D-transposition of the great arteries.

Main Methods:

• Literature review of studies on cardiac growth and hypertrophy.
• Analysis of hemodynamic influences on myocardial development.
• Examination of cellular and molecular changes during cardiac adaptation to pressure overload.

Main Results:

• Normal postnatal cardiac growth involves early myocyte and capillary hyperplasia, followed by myocyte hypertrophy.
• Neonatal pressure overload induces hyperplasia/hypertrophy and angiogenesis; later age induces only hypertrophy.
• The capacity and speed of left ventricular hypertrophy diminish significantly with increasing age.

Conclusions:

• Age-dependent changes in left ventricular hypertrophy capacity support primary arterial switching in neonates.
• The findings support "rapid" two-stage arterial switching for infants older than 3-4 weeks.
• Concerns are raised regarding late left ventricular retraining after failed atrial inversion operations.