A new echocardiographic approach for the detection of non-ischaemic fibrosis in hypertrophic myocardium.

Abstract

Regional myocardial fibrosis detected by magnetic resonance imaging (MRI) using late enhancement (LE) indicates an unfavorable prognosis. We investigated in a prospective study whether regional non-ischaemic fibrosis in hypertrophic myocardium can also be detected by ultrasonic strain-rate imaging based on specific visual features of the myocardial deformation traces. This diagnostic study aimed to define left ventricular fibrotic segments in 30 patients with hypertrophic cardiomyopathy (n = 10), severe aortic valve stenosis (n = 10), Fabry disease cardiomyopathy (n = 10), and 10 healthy controls. MRI and strain-rate imaging (=deformation imaging) was performed in all patients and controls to detect LE. In total, 42 segments showed LE according to MRI criteria. Using strain-rate imaging, all LE positive segments displayed a characteristic pattern consisting of a first peak in early systole followed by a rapid fall in strain rate close to zero and a second peak during isovolumetric relaxation. This 'double peak sign' was never seen in segments of healthy controls. However, it was detected in 10 segments without LE. These 'false-positive' segments belonged to Fabry patients who often develop a fast progressing fibrosis. In a follow-up MRI study after 2 years (available for 6/10 segments), all these segments had developed LE. The 'double peak sign' in strain-rate imaging tracings seems to be a reliable tool to diagnose regional fibrosis.