The measurement of wall stress allows study of morphological adaptation of the left ventricle, especially in conditions associated with symmetric hypertrophy (hypertension, aortic stenosis). The calculation is performed in hypertensive heart disease but not in aortic stenosis because of the ventriculo-aortic pressure gradient. In a preliminary study, the authors validated the peak systolic left ventricular pressure calculated by adding the systolic brachial artery pressure to the maximal transvalvular pressure gradient by comparing the value with that obtained by catheterization in 21 patients with aortic stenosis. The second phase of the study was to measure meridian and circumferential wall stress prospectively in 35 patients with aortic stenosis (29 symptomatic, 6 asymptomatic) and to compare the results with those observed in 21 normal subjects. In the latter group, the values were 151 +/- 22 and 311 +/- 37 10(3) dynes/cm2 respectively, whereas in asymptomatic aortic stenosis the stresses were 136 +/- 28 and 303 +/- 41 10(3) dynes/cm2 respectively (NS) and in symptomatic aortic stenosis 210 +/- 55 and 437 +/- 94 10(3) dynes/cm2 respectively (p < 0.0001). None of the cases of asymptomatic aortic stenosis had raised wall stress values whereas only 6 symptomatic aortic stenosis patients had normal wall stress. The values of wall stress obtained using the method proposed were comparable to those reported by other authors with invasive investigations. Non-invasive measurement of wall stress by Doppler echocardiography may be proposed as a method of evaluation of left ventricular adaptation, especially in severe stenosis and in patients with a patent geometric abnormality (abnormal dilatation or even an inadequately hypertrophied wall).