Systolic time intervals in children: normal standards for clinical use

Area of Science:

• Pediatric Cardiology
• Cardiovascular Physiology

Background:

• Accurate assessment of left ventricular performance is crucial in pediatric cardiology.
• Establishing reliable reference standards for systolic time intervals in children is necessary for clinical evaluation.

Purpose of the Study:

• To derive regression equations for systolic time intervals in normal children.
• To establish reliable clinical standards for assessing left ventricular performance in pediatric patients.

Main Methods:

• Measurement of systolic time intervals in 253 normal children.
• Utilized stepwise regression analysis to identify relevant variables (heart rate, age).
• Developed regression equations for electromechanical systole (QS2), left ventricular ejection time (LVET), and pre-ejection period (PEP).

Main Results:

• Heart rate was the primary determinant for QS2 and LVET in both sexes.
• Heart rate was the main determinant for PEP in males; age had a minor influence in females.
• The PEP/LVET ratio was largely independent of heart rate and age, with a consistent mean value (0.30 ± 0.04).

Conclusions:

• Regression equations based on heart rate offer practical clinical standards for pediatric systolic time intervals.
• The PEP/LVET ratio can be used universally across children, independent of age and heart rate.
• The described methods are practical for routine clinical use in children, providing a reliable basis for assessment.