Systolic Heterogeneity of Transmural Myocardial Function in Normal Subjects: Physiological Functional Heterogeneity.

Abstract

Because of the lack of a clinical method for assessing the transmural myocardial function, few studies on the heterogeneity during the myocardial contraction/relaxation sequence inside the human ventricular wall have been reported, despite the fact that the importance of the pathophysiology in the transmural heterogeneity has been stressed in previous experimental studies. We studied the transmyocardial functional heterogeneity of the basal anteroseptal segment in normal subjects (n = 8, 40.0 +/- 12.8 year, male), adopting the novel high resolution Doppler measurement "Phased Tracking Method". Each transmural layer of 0.75 mm thickness showed functional heterogeneity (physiological transmural functional heterogeneity), namely larger thickening occurred in the left ventricular endocardial side (right side 1/3: 26.1 +/- 5.2% of the total wall thickness, middle 1/3: 31.9 +/- 2.7%, left side 1/3: 42.1 +/- 6.4%) and the peak thickening shifted smoothly in time from the middle layers to the left subendocardial side during the contraction period. We concluded that transmural functional heterogeneity does exist in normal subjects as well as in the experimental animals of previous reports. Smooth and coordinate myocardial layer contraction across the ventricular wall (physiological transmural functional heterogeneity) is fundamental to maintain the normal ventricular function.

Noninvasive early detection of anthracycline‐induced cardiotoxicity in patients with hematologic malignancies using the phased tracking method

“…The PTM, which was employed in this study, has been applied to clinical studies by many researchers, that is, noninvasive evaluation of the myocardial property of contraction and relaxation [5,30,31], elasticity of the arterial wall [32][33][34][35][36], and fatal cardiac or artery [7,8,37]. Although in this study, we reported only V ave during systolic time at the left ventricular septum, we hypothesize that the development of more detailed myocardial damaging process becomes clear by analyzing the continuous temporal relationship with V ave , V max , and color image.…”

“…The development of noninvasive, reproducible, easy‐to‐use, sensitive diagnostic techniques would greatly improve the detection of early pathological changes associated with treatment regimens . One such technique is the phased tracking method (PTM) , a high‐resolution Doppler measurement that is useful for detecting cardiac transmural changes , the PTM is measured on minute amplitude on the order of several tens of micrometers up to several hundred Hertz, which has neither been recognized in TDI nor standard M‐mode, B‐mode, 2D‐strain echocardiography. These fine measurement characteristics and the rapid minute amplitude have allowed measurement of the fetal heart and the fetal descending aorta of normal and growth‐restricted fetuses .…”

“…The development of noninvasive, reproducible, easy-to-use, sensitive diagnostic techniques would greatly improve the detection of early pathological changes associated with treatment regimens [2,3]. One such technique is the phased tracking method (PTM) [4], a highresolution Doppler measurement that is useful for detecting cardiac transmural changes [5,6], the PTM is measured on minute amplitude on the order of several tens of…”