Positive influence of aging on the occurrence of fat replacement in the right ventricular myocardium determined by multislice-CT in subjects with atherosclerosis

Severe Myocardial Steatosis: Incidental Finding or a Significant Anatomic Substrate for Sudden Cardiac Arrest?

Myocardial steatosis, also known as lipomatosis cordis, is characterized by adipose tissue within the myocardium without significant fibrosis. Evidence suggests that accumulation of fat can disturb the normal electromechanical physiology of the myocardium. Herein, we discuss the case of a 60-year-old woman with a history of chronic obstructive pulmonary disease who died because of anoxic encephalopathy after a sudden cardiac arrest (SCA). An electrocardiogram showed QRS fragmentation noted as notched R in inferior leads. The autopsy revealed a very small thromboembolus in a distal subsegmental branch of the pulmonary artery, which could not explain the SCA. There was an extensive intramyocardial accumulation of adipose tissue involving the right ventricle and interventricular septum, which split the myocardium into discrete bundles. Arrhythmogenic right ventricular cardiomyopathy was ruled out based on the absence of typical fibrofatty changes. The mechanism of fat replacement was likely secondary to redistribution of visceral fat in the setting of Cushing syndrome. We propose that severe myocardial steatosis can create an anatomic substrate to facilitate the development of SCA. Myocardial steatosis should be reported to identify patients who are at risk for developing cardiovascular events secondary to extreme cardiac adiposity.

Age-related histomorphometric and immunohistochemical changes of the moderator band in Egyptian Baladi cattle

The moderator band (MB) is a common fibromuscular anatomical structure for the right ventricle of most animals. The histomorphometric and immunohistochemical analysis of the MBs of Egyptian Baladi cattle in relation to age was the aim of this study. Eighteen clinically healthy animals of both sexes were used for this study. The animals were divided into three groups depending on age, group I (N = 4, <1 year), group II (N = 8, 1-2 years) and group III (N = 6, 4-8 years). Cross sections of the MBs from all groups were stained with H&E, Masson's trichrome and anti-connexin43 (Cx43) antibody for histological and immunohistochemical examinations. Also, measurements for the thickness of the endocardium of the MB as well as, the wall of its muscular artery were conducted. Bundles of Purkinje fibres (PFs) were identified peripherally in the endocardial layer and among the myocardial fibres in the core of each MB. The infiltration of endocardial adipocytes was the characteristic for MBs of old animals. All morphometric data showed a significant increase with the advancement of age. Immunohistochemical findings revealed the localization and distribution of Cx43 in the PFs and intercalated discs of all examined MBs. However, variation of Cx43 immunoreactivity was found among the groups depending on the age. On the basis of this study, this conclusion of different histomorphometry and Cx43 expression of the MBs in relation to age was drawn. These interesting findings provide further insight into age-related physiological and pathological heart conditions.

Fatty foci within the heart diagnosed with ECG-gated multi-slice computed tomography: frequency and morphology

BACKGROUND

The purpose of our study was to analyze the frequency of focal fatty replacement (FR) of the heart, as well as the distribution and detailed morphology of FR in a large group of patients referred to multi-slice computed tomography with ECG-gating examinations (ECG-MSCT) for various clinical reasons.

MATERIAL AND METHODS

The ECG-MSCT examinations of 1830 consecutive patients were analyzed. The examinations were performed using 8-row (1015 patients) and 64-row (815 patients) MSCT, in pre- and post-contrast scanning. We analyzed the morphology of FR, the dimensions and densities of changes, as well as the morphology and localization of FR with regard to clinical diagnosis.

RESULTS

204 subjects (11.1%) had FR within the heart (113 men; 91 women; mean age 57.8 years); 66% of fatty foci were seen only in the native scanning. The distribution of the fat was: right ventricle (RV) 31.9%, left ventricle (LV) 21.5%, biventricular 39.7%, interventricular or atrial septum 5.9%, and atria 1%. In the RV, fat was localized mainly in the papillary muscles, while in the LV fat was mainly subendocardial (p<0.001). The morphology of the fat was: linear 61.6%, oval 14.8%, punctuate 10.6%, irregular 10.2%, and bilobular 2.8%. Fat was primarily located subendocardially in the LV in patients after myocardial infarction. In patients with suspected coronary artery disease, it was mainly observed subpericardially in the RV and in papillary muscles (p<0.001).

CONCLUSIONS

The incidental frequency of FR within the heart in patients diagnosed with the ECG-MSCT examinations is about 11%. Pre-contrast scanning is the most valuable for FR assessment.

Diagnostic accuracy of 320-slice computed-tomography for detection of significant coronary artery stenosis in patients with various heart rates and heart rhythms compared with conventional coronary-angiography

PURPOSE

To evaluate the diagnostic accuracy of 320-slice CT for detection of significant coronary artery stenosis in patients with various heart rates (HR) and heart rhythms, including tachycardia and chronic atrial-fibrillation (CAF) compared with conventional-coronary-angiography (CAG).

MATERIALS AND METHODS

One-hundred-six consecutive patients underwent both 320-slice CT and CAG within 3 months (normal-sinus-rhythm [NSR] 91.5%, CAF 8.5%, mean HR 65 ± 15 beats/min). There were no cardiac events between the 2 procedures. Patients were divided in 2 groups: Group 1 (HR <65 with NSR at CT scan, n=62), and Group 2 (HR >64 with NSR or heart rhythm irregularities at CT scan, n=44). Patients with >50% or >75% luminal stenosis on CT were compared with those with >50% or >75% stenosis on CAG, respectively.

RESULTS

In a segment-by-segment analysis, in all patients, sensitivity, specificity, positive (PPV) and negative predictive value (NPV) of >50% stenosis on CT for predicting >50% stenosis on CAG were 69, 98, 78, and 97%, respectively, and those of >75% stenosis on CT for predicting >75% stenosis on CAG were 78, 98, 64, and 99%, respectively. Sensitivity, specificity, PPV, and NPV of >50% and 75% stenosis on CT for predicting >50% and >75% stenosis, respectively, on CAG were comparable. Diagnostic accuracy was essentially the same in both groups.

CONCLUSION

320-slice CT had high diagnostic accuracy for the detection of significant coronary artery stenosis compared with CAG. Even though the numbers were small, patients with high HR or heart rhythm irregularities might have essentially equivalent results to those with low HR with NSR.