[Interrelationships among cardiohaemodynamic parameters in human postnatal ontogenesis]

Area of Science:

• Cardiovascular Physiology
• Human Development

Context:

• The transition from infancy to adulthood involves significant physiological changes in the cardiovascular system.
• Understanding these developmental changes is crucial for assessing cardiac health and function across the lifespan.

Purpose:

• To quantify the changes in stroke volume (SV), arterial systolic pressure (ASP), and heart rate from one day old to 20 years of age.
• To analyze the developmental trend of the N coefficient (SV/ASP ratio) and peripheral resistance.
• To evaluate the impact of reduced afterload on the heart's mechanical work during this developmental period.

Summary:

• Stroke volume increases from 5.4 to 70 ml, and arterial systolic pressure rises from 60 to 120 mm Hg.
• Heart rate decreases from 136 to 70 beats/min, while the N coefficient (SV/ASP) improves from 0.1 to 0.6.
• Peripheral resistance drops from 76 to 28 mm Hg x ml(-1) x min(-1), leading to a six-fold reduction in the heart's mechanical workload.

Impact:

• Provides normative data for cardiovascular parameters during human growth and development.
• Highlights the significant decrease in cardiac afterload and its beneficial effect on myocardial efficiency.
• Offers insights into the physiological adaptations that support increased circulatory demands throughout adolescence.