Abstract and Introduction
Abstract
Background: We tested the hypothesis that the apical myocardial mechanics differ from those of other ventricular segments in hypertensive patients with and without apical hypertrophic cardiomyopathy (ApHCM).
Methods: We retrospectively studied hypertensive patients with and without ApHCM. Left ventricular longitudinal, circumferential, and radial strains were examined by two-dimensional speckle-tracking echocardiography at the basal, middle, and apical walls of the parasternal short-axis and apical 2-, 3- and 4-chamber views.
Results: Fourteen consecutive patients with hypertension and ApHCM and 14 patients with hypertension without ApHCM were studied. Lower mitral annular peak systolic velocity and greater diastolic dysfunction were present in hypertensive patients with ApHCM than in hypertensive patients without ApHCM. Compared with hypertensive patients without ApHCM, hypertensive patients with ApHCM had significantly lower apical longitudinal (−13.9% vs −21.9%, p = 0.010) and radial strains (4.4% vs 11.5%, p = 0.017) without the base-to-apex gradient. The global longitudinal (−15.6% vs −18.8%, p = 0.027) and circumferential strains (−16.1% vs −19.2%, p = 0.019) were significantly lower in hypertensive patients with ApHCM than in hypertensive patients without ApHCM. Among systolic parameters, the global longitudinal strain was independently associated with hypertension with ApHCM (odds ratio, 1.457; 95% confidence interval, 1.002–2.119; p = 0.049).
Conclusions: Reduced apical longitudinal and radial strains without a base-to-apex gradient were present in hypertensive patients with ApHCM. The global longitudinal strain was independently associated with ApHCM in hypertensive patients.
Introduction
Apical hypertrophic cardiomyopathy (ApHCM), in which the myocardial wall thickening is localized at the apex of the left ventricle, is comparatively rare in western countries in comparison with Asia. ApHCM is described as an electrocardiographic pattern of giant negative T waves and an angiographic feature of end-diastolic left ventricular cavity structure resembling an 'ace of spades'. It has a benign clinical course in terms of cardiovascular mortality; however, it may be associated with serious complications, such as myocardial infarction and arrhythmias. Less benign clinical outcomes of patients with ApHCM and hypertension have been observed recently. The presentation of ApHCM in the setting of chronic hypertension is recognized as an important issue because an accurate diagnosis has an impact on prognosis and management.
Echocardiographic strain imaging is an innovative approach recently developed for the assessment of left ventricular myocardial mechanics. Myocardial strain can be determined using tissue Doppler imaging or two-dimensional speckle tracking. Doppler-based techniques are limited by the angle-dependence of the signal, precluding the assessment of apical left ventricular function. In contrast, two-dimensional speckle tracking studies orthogonal components of strain independent of the insonation angle because it tracks deformation between acoustic markers in the ultrasonic image in two dimensions. Few studies have addressed regional myocardial mechanics in patients with ApHCM, and 2-dimensional deformation imaging studies of hypertensive patients with and without ApHCM are lacking. For the present study, we hypothesized that regional myocardial mechanics of the apex differed from those of the other ventricular segments in hypertensive patients with and without ApHCM. Therefore, in this retrospective 2-dimensional echocardiographic study, we investigated left ventricular deformation in hypertensive patients with and without ApHCM.