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Relation of left ventricular mass, preload, afterload and contractility in pediatric patients with essential
T R Kimball1, S R Daniels, J M Loggie
1Department of Pediatrics, Children's Hospital Medical Center, Cincinnati, Ohio 45229.
Insights
In hypertensive children, left ventricular mass is not significantly linked to contractility. Elevated preload and systemic vascular resistance may contribute to left ventricular hypertrophy development.
Area of Science:
- Pediatric Cardiology
- Cardiovascular Physiology
- Hypertension Research
Background:
- Left ventricular hypertrophy (LVH) in adults is associated with decreased contractility and increased preload.
- Understanding LVH correlates in pediatric hypertension is crucial for early intervention.
Purpose of the Study:
- To investigate the relationship between left ventricular (LV) preload, afterload, and contractility with LV mass index in pediatric hypertensive patients.
Main Methods:
- Echocardiography was used to assess LV mass, preload (diastolic dimension/volume), and afterload (end-systolic wall stress, vascular resistance, blood pressure) in 90 pediatric hypertensive patients.
- Contractility was evaluated using the end-systolic stress/volume ratio and the difference between measured and predicted velocity of circumferential fiber shortening.
- Univariate and multivariate analyses were performed to identify significant correlates.
Main Results:
- Univariate analysis revealed significant correlations between LV mass and body mass, black race, diastolic dimension, diastolic volume, and the stress/volume ratio.
- Contractility, assessed by the difference between measured and predicted velocity of circumferential fiber shortening, was not significantly correlated with LV mass.
- A multivariate model identified body mass, age at diagnosis, diastolic dimension, wall stress, and vascular resistance as significant factors, but not contractility measures.
Conclusions:
- Contractility does not appear to be a significant correlate of left ventricular mass in hypertensive pediatric patients.
- The observed correlation between LV mass and the stress/volume ratio may be influenced by loading conditions.
- Elevated preload and systemic vascular resistance are hypothesized to play a role in the development of left ventricular hypertrophy in this population.
Objectives:
The aim of this study was to determine if left ventricular preload, afterload or contractility is a correlate of left ventricular mass index in hypertensive pediatric patients.
Background:
It is believed that decreased contractility and increased preload are associated with left ventricular hypertrophy in adult hypertensive patients.
Methods:
Ninety pediatric hypertensive patients underwent echocardiography to assess left ventricular mass, preload (diastolic dimension and volume) and afterload (end-systolic wall stress, vascular resistance and blood pressure). Contractility was assessed by 1) the end-systolic stress/volume ratio, and 2) the difference between measured and predicted velocity of circumferential fiber shortening. Univariate and multivariate analyses were performed.
Results:
Univariate analysis showed significant correlations between left ventricular mass and 1) body mass (r = 0.33, p < 0.001), 2) black race (r = 0.37, p < 0.0003), 3) diastolic dimension (r = 0.26, p < 0.01), 4) diastolic volume (r = 0.20, p < 0.05), and 5) stress/volume ratio (r = -0.53, p < 0.0001) but not the difference between measured and predicted velocity of circumferential fiber shortening. A multivariate model included body mass, age at diagnosis, diastolic dimension, wall stress and vascular resistance but not the difference between measured and predicted velocity of circumferential fiber shortening.
Conclusions:
Contractility is not significantly related to left ventricular mass. The positive correlation between mass and stress/volume may be due to the dependence of the latter variable on loading conditions. We speculate that both elevated preload and systemic vascular resistance may have a role in the development of hypertrophy in hypertensive pediatric patients.