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Aims: In this study, we investigated the clinical usefulness of ultrasonic tissue characterization with integrated backscatter for the evaluation of myocardial histological abnormalities in comparison with endomyocardial biopsy findings in patients with hypertrophic cardiomyopathy. Methods: Twenty patients with hypertrophic cardiomyopathy and 20 normal subjects were enrolled in this study. We measured two parameters for the ultrasonic tissue characterization with integrated backscatter: the magnitude of the cardiac-cycle-dependent variation in integrated backscatter signals (cdv-IB) and the mean value of integrated backscatter signals calibrated by the pericardium (cal-IB). These parameters were measured at both the interventricular septum and the left ventricular posterior wall. Histological findings of right ventricular endomyocardial biopsy specimens were analyzed by computer image analyzer. Results: cdv-IB was significantly lower and cal-IB significantly higher in both the interventricular septum and the left ventricular posterior wall in patients with hypertrophic cardiomyopathy compared with normal subjects. In patients with hypertrophic cardiomyopathy, the degree of myocardial disarray, interstitial fibrosis, and nonhomogeneity of myocyte size showed positive correlations with cal-IB and negative correlations with cdv-IB. Conclusions: Ultrasonic tissue characterization with IB enables the noninvasive evaluation of myocardial histological abnormalities in patients with hypertrophic cardiomyopathy.

Apoptotic myocardial cell death occurs in the setting of ARVC and may contribute to the loss of myocardial cells.

CV-IB was correlated with both the extent of fibrosis in myocardial tissue and the myocyte diameter. These findings suggest that ultrasonic tissue characterization is a good indicator of the severity of fibrosis and myocyte atrophy in patients with DCM.

Atrial fibrillation (AF) is a risk factor for cerebral embolism, with the left atrial appendage (LAA) being considered as the source of emboli. However, the relationship between the histologic properties of LAA thrombi and the occurrence of cerebral embolism is not known. Seventy-six hearts from patients who died within 1 month after cerebral embolism were studied at autopsy. Patients were grouped according to the presence of AF and the presence of valvular disease (VD). We determined whether the LAA thrombi adhered to the trabecular region or the remainder of the LAA. LAA thrombi were grouped into three stages: a fresh stage in which thrombi consisted of fibrin and platelets, an organizing stage in which angiogenesis was observed in the thrombi, and an organized stage in which endothelial cells covered the surface of the thrombi. The AF+/VD– group included 19 patients (25.0%), the AF+/VD+ group 8 (10.5%), the AF–/ VD– group 37 (48.7%), and the AF–/VD+ group included 12 patients (15.8%). LAA thrombi were observed in 15 patients (78.9%) in the AF+/VD– group, and all of the thrombi adhered to the trabecular region. Thrombi in the fresh and the organizing stages were observed in 10 patients (66.7%). Patients in the AF+/VD– group accounted for about 25% of the cases of cerebral embolism. All of these thrombi were attached to the trabecular region, and about 70% of them could represent an embolic source.