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The influence of age on cardiac refractory periods in man
Insights
Cardiac refractory periods change significantly with age. Younger individuals, from infants to adults, generally exhibit shorter refractory periods compared to older individuals, impacting cardiac electrophysiology.
Area of Science:
- Cardiology
- Electrophysiology
- Pediatric Cardiology
Background:
- Age is a known factor influencing cardiac refractory periods.
- Understanding age-related changes in cardiac electrophysiology is crucial for clinical practice.
Purpose of the Study:
- To investigate the relationship between age and cardiac refractory periods across a wide age spectrum.
- To document changes in refractory periods from infancy through adulthood.
Main Methods:
- Seventy patients with normal atrioventricular (A-V) conduction were analyzed.
- Patients were stratified into six age groups (7 months to 77 years).
- The extrastimulus technique was employed to determine refractory periods at various cycle lengths.
Main Results:
- Younger age groups demonstrated a trend towards shorter cardiac refractory periods compared to older groups.
- Statistical analysis revealed significant differences (p < 0.05-0.001) in refractory periods across age groups.
- Full recovery times of the A-V node were assessed within pediatric groups.
Conclusions:
- Cardiac refractory periods exhibit significant age-dependent variations.
- Age-related changes in refractory periods are evident from infancy into adulthood.
- These findings contribute to understanding normal electrophysiological development and aging.
Abstract:
As age is a determinant of cardiac refractory periods, this communication describes changes of refractory periods in an age continuum of infants, children and adults, 7 months through 77 years. Seventy patients with evidence of normal A-V conduction on scalar electrocardiogram were included. The patients were divided into six age groups: less than 2 years, 3-5 years, 6-10 years, 11-15 years, 16-30 years, and greater than 30 years. Extrastimulus technique was used to determine refractory periods in sinus rhythm or at longest cycle length assuring atrial capture, then at shorter cycle lengths. Cycle lengths (CL) for each age group were divided into ranges: CL1, 1,000-600 msec; CL2, 599-460 msec; CL3, less than 459 msec. Refractory periods at the three CL's within each age group were determined. Full recovery times of the A-V node within groups of children were determined. Statistical significance of the data was found by analysis of variance. The younger group tended to have shorter values than the older groups (F less than 0.05-0.001).