Heart rate effects on strain and strain rate in healthy children.

Based on myocardial Doppler echocardiography, regional strain (S) and strain rate (SR) can be evaluated as regional parameters of ventricular function. The use of these techniques in clinical pediatric cardiology remains a challenge. This study establishes reference values for S and SR in both systole and diastole in healthy children over a large age range and evaluates the potential relationships of demographic and echocardiographic parameters on S and SR, and, in particular, assesses the clinical effect of heart rate on S and SR in healthy children. It is shown that heart rate changes in children during growth have an important impact on both systolic and diastolic myocardial S and late diastolic SR. Therefore, to evaluate regional myocardial function in children, heart rate at rest should be considered an important factor.