Pediatric Cardiovascular System – Detailed Information

I. Origin and Development of the Cardiovascular System

• Origin: The heart and blood vessels develop from the mesoderm, a layer of embryonic tissue.
• Start of Contraction: The heart begins to contract on the 22nd day of pregnancy.
• Heart Development:
  • During pregnancy: The right ventricle has a cardiac output 1.3 times that of the left ventricle due to the non-functioning lungs.
  • After birth: The left ventricle gradually dominates as the lungs become functional, providing oxygen to the body.

II. Characteristics of the Newborn Cardiovascular System

• Average Blood Pressure: 75/50 mmHg in full-term newborns.
• Heart Weight:
  • Newborn: Approximately 25g, accounting for 0.9% of body weight.
  • The heart is slightly round, horizontally positioned, and high.
  • The heart grows significantly in weight during the first few years of life, reaching adult size by puberty.
  • Left ventricle to right ventricle mass ratio: 1.4 in newborns, 2.76 in adults.

III. Comparison of Newborn Circulation and Older Children’s Circulation

IV. Other Important Characteristics

• Foramen Ovale (FO): Closes within 1-2 years after birth.
• Patent Ductus Arteriosus (PDA): Closes within 1-2 weeks after birth; failure to close can cause cardiovascular disease.
• Heart Structure:
  • Left Ventricle: Develops more strongly than the right ventricle.
  • Myocardium: Develops robustly in two phases: after birth and pre-puberty.
• Electrocardiogram (ECG) by Age:
  • 0-1 years:
  • 2-7 years:
  • 7-12 years:
• Aortic (Ao) and Pulmonary Artery (PA) Diameter:
  • Children under 10 years old: PA larger than Ao.
  • 10-12 years old: PA equal to Ao.
  • Over 12 years old: Ao larger than PA.
• Blood Vessels:
  • Newborn: Arterial diameter nearly equal to Ao.
  • Femoral Artery: Difficult to palpate or weaker than the radial artery in case of coarctation of the aorta.
• Heart Sounds S1, S2:
  • At the heart base: S1 louder than S2.
  • At the heart apex: S2 louder than S1.
• Cardiovascular Changes:
  • Heart Rate: Varies with age, physical activity, and health status.
  • Blood Pressure: Gradually increases with age.
  • Cardiac Output: Gradually increases with age.
• Blood Pressure Measurement in Children:
  • Use a cuff appropriate for the child’s arm size.
  • Measure in a sitting or lying down position.
  • Perform at least three measurements, 1-2 minutes apart.
  • Record the obtained blood pressure for each measurement.
• Blood Volume:
  • Newborn: Approximately 2-3 liters.
  • Breastfed: Approximately 4-5 liters.
  • 6-7 years old: Approximately 6-7 liters.
  • Older children: Approximately 8-9 liters.
• Pulse Rate by Age:
  • Newborn: 120-160 beats/minute.
  • 1 year old: 100-140 beats/minute.
  • 5 years old: 80-120 beats/minute.
  • 10 years old: 70-100 beats/minute.
• Heart Width: 7-8% of body height.
• Fetal Cardiac Output: 450 ml/kg/minute.
• Blood from Ao to Placenta: Approximately 65% of blood volume.
• Blood Flow from Ao Up Through Coarctation of the Aorta Into Descending Ao: Approximately 10% of cardiac output.

Note:

• The above information is for reference only.
• For accurate information on your child’s health, consult a cardiologist.
• Monitoring and caring for your child’s cardiovascular health is crucial for their overall development.

Conclusion:

The cardiovascular system plays a vital role in human life. Understanding the development and characteristics of the cardiovascular system in children helps us effectively care for their health.