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Influence of maturation on diastolic events of left ventricle in children
1Department of Pediatrics, National Taiwan University Hospital, Taipei, R.O.C.
Insights
Cardiac maturation significantly impacts diastolic filling patterns. While isovolumic relaxation period is age-independent, early diastolic filling velocity increases with age, suggesting altered relaxation in younger hearts.
Area of Science:
- Cardiology
- Pediatric Cardiology
- Cardiac Physiology
Background:
- Cardiac diastolic function is crucial for heart health.
- Understanding age-related changes in diastolic events is vital for diagnosing pediatric cardiac conditions.
Purpose of the Study:
- To investigate how the maturation process influences diastolic events in the cardiac cycle.
- To establish age-specific correlations for diastolic periods and filling dynamics.
Main Methods:
- M-mode and Doppler echocardiography performed on 120 healthy subjects (1 hour to 16 years).
- Analysis of isovolumic relaxation period (IVRP), diastolic total period (DTP), and early diastolic filling (D-F) in relation to cardiac cycle length (CL).
- Assessment of early (E) and atrial (A) diastolic filling velocity ratios across different age groups.
Main Results:
- Isovolumic relaxation period (IVRP) showed no statistical difference across age groups but correlated positively with cardiac cycle length (CL) within age-specific equations.
- Diastolic total period (DTP) and early diastolic filling (D-F) demonstrated linear correlations with CL and DTP, respectively, applicable across all ages (DTP = 0.58 x CL - 75.2; D-F = 0.57 x DTP + 0.11).
- The ratio of early (E) to atrial (A) diastolic filling velocities increased with age, primarily due to increased E velocity, indicating potentially depressed early diastolic filling in younger individuals.
Conclusions:
- Diastolic relaxation and filling patterns are significantly influenced by maturation.
- Age-related changes in diastolic function result from complex interactions between cellular properties and loading conditions.
- Early diastolic filling may be less efficient in younger hearts compared to older individuals.
Abstract:
To delineate the influence of maturation process on diastolic events of cardiac cycle, we had performed M-mode and Doppler echocardiography in 120 normal subjects aged from 1 hour to 16 years. The isovolumic relaxation period (IVRP, msec), defined as the time interval between the aortic valve closure to the mitral valve opening, was not statistically different in various age groups. Different equations based on individual ranges of cycle length (CL) were disclosed for each of three different age groups, demonstrating a positive linear correlation between IVRP and CL. On the contrary, an equation showing a linear correlation between diastolic total period (DTP, msec) and CL could be applied to all age groups: DTP = 0.58 x CL-75.2 (r = 0.89, p less than 0.001). Similarly applicable to all age groups, the duration of early diastolic filling (D-F, msec) changed with DTP in all age groups by an equation: D-F = 0.57 x DTP + 0.11 (r = 0.93, p less than 0.001). Ratios between the maximal velocity of early (E) and atrial (A) diastolic filling increased gradually with age. This was largely due to an increase in E with maturation, suggesting a depressed early diastolic filling in the young hearts. We conclude that the patterns of diastolic relaxation and filling are heterogeneously affected by the degree of maturation and represent the net results of complex interactions between changing inactivation properties and loading status at various stages.