High prevalence of septal thickness overestimation in hypertensive subjects and controls

The aim of our study was to assess the frequency of important problems in the ultrasonic estimate of septal thickness as a consequence of multiple endocardial lines inside the septum in echocardiographic tracings of otherwise good technical quality. We performed an echocardiographic study in a population composed of 311 subjects (131 essential hypertensive subjects and 180 normotensive healthy controls) by using M-mode echocardiography under two-dimensional control, according to the recommendations of the American Society of Echocardiography. We observed the presence of one or more continuous lines inside the septum, each of them simulating an endocardial border and thus producing the appearance of two or more superimposed septal thicknesses differing by 2 mm or more in greater than 50% of the subjects (54% normotensive and 56% hypertensive). Furthermore, within the group of subjects with multiple septal lines, we found the disappearance of at least one of the farthest linear echoes, with resulting septal thinning of almost 2 mm in 58% of the normotensive and 61% of the hypertensive subjects. These findings suggest the need for caution when interpreting echocardiographic measurements of left ventricular septal thickness. We suggest that in the presence of multiple lines inside the septum, the echocardiographic examination should be continued up to the appearance of the thinnest septal image, possibly devoid of multiple lines inside the septum.