Abstract
A pilot study was performed to reveal the potentials of new echo Doppler techniques for the detection of myocardial changes due to congenital valvar aortic stenosis. A total of 24 patients, (age range 0.1 to 17 years), with various degrees of aortic stenosis, and 24 age- and gender-matched, healthy children were enrolled in this study. Conventional echo Doppler, tissue velocity imaging (TVI) and strain-rate imaging (StRI) measurements were carried out using the apical four-chamber view and transthoracic long-axis view. All patients had normal fractional shortening of the left ventricle (> 28%). Although the sum of septal and ventricular wall thicknesses was significantly increased in the patients (p < 0.001), only 6 of the 24 patients showed left ventricular hypertrophy. In tissue velocity mode, systolic and early diastolic wall velocity acceleration was significantly reduced in both views. Peak systolic and early diastolic wall velocities, as well as strain rate values, in the four-chamber view were significantly reduced in the patient group. The decrease was highest for the strain-rate values in all cases. In conclusion, strain rate values at different moments within the heart cycle might become important parameters in the assessment of myocardial impairment. Further studies are indicated to assess the correlation of these parameters with the severity of stenosis, left ventricular hypertrophy and irreversible myocardial function changes.
