Histological validation of atrial structural remodelling in patients with atrial fibrillation.

BACKGROUND AND AIMS: This study aimed to histologically validate atrial structural remodelling associated with atrial fibrillation. METHODS AND RESULTS: Patients undergoing atrial fibrillation ablation and endomyocardial atrial biopsy were included (n = 230; 67 ± 12 years old; 69 women). Electroanatomic mapping was performed during right atrial pacing. Voltage at the biopsy site (Vbiopsy), global left atrial voltage (VGLA), and the proportion of points with fractionated electrograms defined as ≥5 deflections in each electrogram (%Fractionated EGM) were evaluated. SCZtotal was calculated as the total width of slow conduction zones, defined as regions with a conduction velocity of <30 cm/s. Histological factors potentially associated with electroanatomic characteristics were evaluated using multiple linear regression analyses. Ultrastructural features and immune cell infiltration were evaluated by electron microscopy and immunohistochemical staining in 33 and 60 patients, respectively. Fibrosis, intercellular space, myofibrillar loss, and myocardial nuclear density were significantly associated with Vbiopsy (P = .014, P < .001, P < .001, and P = .002, respectively) and VGLA (P = .010, P < .001, P = .001, and P < .001, respectively). The intercellular space was associated with the %Fractionated EGM (P = .001). Fibrosis, intercellular space, and myofibrillar loss were associated with SCZtotal (P = .028, P < .001, and P = .015, respectively). Electron microscopy confirmed plasma components and immature collagen fibrils in the increased intercellular space and myofilament lysis in cardiomyocytes, depending on myofibrillar loss. Among the histological factors, the severity of myofibrillar loss was associated with an increase in macrophage infiltration. CONCLUSION: Histological correlates of atrial structural remodelling were fibrosis, increased intercellular space, myofibrillar loss, and decreased nuclear density. Each histological component was defined using electron microscopy and immunohistochemistry studies.

Ultrastructural features of cardiomyocytes in dilated cardiomyopathy with initially decompensated heart failure as a predictor of prognosis.

AIMS: The aim of the present study was to clarify the significance of myocardial ultrastructural changes in patients with dilated cardiomyopathy (DCM). METHODS AND RESULTS: Endomyocardial biopsy of the left ventricle was performed in 250 consecutive DCM patients (54.9 ± 13.9 years, 79% men), presenting initially as decompensated heart failure (HF). Myofilament changes of cardiomyocytes were evaluated by electron microscopy and compared with clinical and morphometric data. Mortality and HF recurrence were evaluated during the follow-up period. During the follow-up period (4.9 ± 3.9 years), 24 patients (10%) died and 67 (27%) were readmitted because of HF recurrence, including those who had died because of HF. Myofilament changes, classified as either focal derangement of myofilaments (sarcomere damage) or diffuse myofilament lysis (disappearance of most sarcomeres in cardiomyocytes), were identified in 164 patients (66%). Multivariate analysis identified a family history of DCM [hazard ratio (HR) 4.763; 95% confidence interval (CI) 1.012-12.518], atrial fibrillation (HR 6.132; 95% CI 2.188-17.180), haemoglobin level (HR 0.685; 95% CI 0.528-0.889), and diffuse myofilament lysis (HR 4.048; 95% CI 1.427-11.481) as independent predictors of mortality. A family history of DCM (HR 2.268; 95% CI 1.276-4.030), haemoglobin level (HR 0.876; 95% CI 0.785-0.979), focal derangement of myofilaments (HR 7.431; 95% CI 2.916-18.934), and diffuse myofilament lysis (HR 6.480; 95% CI 2.403-17.473) were predictors of readmission due to HF recurrence. CONCLUSIONS: In DCM patients with first-decompensated HF, myofilament changes are strongly associated with mortality and HF recurrence.

Histopathological and clinical characteristics of duodenal gastrointestinal stromal tumors as predictors of malignancy.

BACKGROUND: Although gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the gastrointestinal tract, they are very rare. This study evaluated clinical and histopathological characteristics of duodenal GISTs to identify factors useful in predicting prognosis for patients with these tumors. METHODS: A retrospective study was performed on 20 patients who had undergone surgery between 1987 and 2009 for duodenal GISTs. Clinical, histopathological, and immunohistochemical data were evaluated. Survival analyses were conducted using Kaplan-Meier estimates. RESULTS: In 12 patients (60%), duodenal GISTs were diagnosed incidentally. Eight cases (40%) were classified as high risk grade GISTs. Skeinoid fibers (SkF), which are eosinophilic globular hyaline deposits in the extracellular interstitium of the tumor, were found in 12 patients. Skeinoid fibers were not recognized in 8 cases, and these included 3 cases (37.5%) where tumors recurred after surgery and the patient died. Tumors without SkF were larger (81 ± 92 vs. 23 ± 8 mm, P < 0.001) and had a higher mitotic count (224.0 ± 336.6 vs. 0.0 ± 0.0 /50 high-power field, P < 0.001) than those with SkF. Survival time was shorter in patients with tumors lacking SkF (52.9 ± 50.7 vs. 108.9 ± 86.5 months, P = 0.019). CONCLUSIONS: We have identified clinical and histopathological characteristics that were useful in predicting the prognosis of patients with duodenal GISTs. In this study, 60% of the tumors were found incidentally, SkF were not recognized in tumors from 40% of patients, and all cases of post-operative tumor recurrence and death occurred in this subgroup of patients.

Myocardial ultrastructure can augment genetic testing for sporadic dilated cardiomyopathy with initial heart failure.

AIMS: The aim of the present study was to consider whether the ultrastructural features of cardiomyocytes in dilated cardiomyopathy can be used to guide genetic testing. METHODS AND RESULTS: Endomyocardial biopsy and whole-exome sequencing were performed in 32 consecutive sporadic dilated cardiomyopathy patients [51.0 (40.0-64.0) years, 75% men] in initial phases of decompensated heart failure. The predicted pathogenicity of ultrarare (minor allele frequency ≤0.0005), non-synonymous variants was determined using the American College of Medical Genetics guidelines. Focusing on 75 cardiomyopathy-susceptibility and 41 arrhythmia-susceptibility genes, we identified 404 gene variants, of which 15 were considered pathogenic or likely pathogenic in 14 patients (44% of 32). There were five sarcomeric gene variants (29% of 17 variants) found in five patients (16% of 32), involving a variant of MYBPC3 and four variants of TTN. A patient with an MYBPC3 variant showed disorganized sarcomeres, three patients with TTN variants located in the region encoding the A-band domain showed sparse sarcomeres, and a patient with a TTN variant in encoding the I-band domain showed disrupted sarcomeres. The distribution of diffuse myofilament lysis depended on the causal genes; three patients with the same TMEM43 variant had diffuse myofilament lysis near nuclei (P = 0.011), while two patients with different DSP variants had lysis in the peripheral areas of cardiomyocytes (P = 0.033). CONCLUSIONS: Derangement patterns of myofilament and subcellular distribution of myofilament lysis might implicate causal genes. Large-scale studies are required to confirm whether these ultrastructural findings are related to the causative genes.

Long-term prognostic value of ultrastructural features in dilated cardiomyopathy: comparison with cardiac magnetic resonance.

AIMS: This study aims to determine the implications associated with long-term prognosis of heart failure (HF) in patients with dilated cardiomyopathy (DCM) presenting initially as decompensated HF. We stratified the phase of DCM patients without late gadolinium enhancement (LGE) based on ultrastructural changes in cardiomyocytes. METHODS AND RESULTS: Left ventricular (LV) endomyocardial biopsy was performed in 55 consecutive DCM patients with initial decompensated HF. Ultrastructural changes in cardiomyocytes detected by electron microscopy were compared with data including LGE with cardiac magnetic resonance and HF recurrence. Of the 55 DCM patients, 24 (44%) showed LGE, and 26 (47%) showed recurrence decompensated HF, while 23 patients (42%) showed autophagic vacuoles in cardiomyocytes by electron microscopy. Multivariate analysis identified atrial fibrillation [hazard ratio (HR), 3.40; 95% confidence interval (CI), 1.45-7.98], haemoglobin level (HR, 0.82; 95% CI, 0.68-0.99), beta-blocker use (HR, 0.18; 95% CI, 0.05-0.74), and autophagic vacuoles (HR, 0.25; 95% CI, 0.09-0.65) as predictors of HF recurrence in the total patient population. In patients without LGE, only autophagic vacuoles were independent predictors of readmission because of HF (HR, 0.29; 95% CI, 0.09-0.90). In patients with LGE, atrial fibrillation (HR, 19.10; 95% CI, 2.97-123.09), and mid-linear LGE (HR, 12.96; 95% CI, 2.02-82.94) were independent predictors of readmission because of HF. CONCLUSIONS: In DCM patients with LGE, characterised by progression of LV remodelling, the LGE pattern was a predictor of HF recurrence, whereas in patients without LGE, absence of autophagic vacuoles was a predictor of HF recurrence.

Histopathological evaluation of left atrial appendage thrombogenesis removed during surgery for atrial fibrillation.

BACKGROUND: In this study, we histopathologically assessed left atrial appendages (LAAs) resected during surgical treatment for atrial fibrillation (AF) to elucidate the mechanism of intra-LAA thrombus formation in valvular AF. METHODS: The clinicopathological study of resected LAA was made on 56 valvular AF cases: 28 with mitral regurgitation (MR), 3 with mitral stenosis, and 25 with mitral stenosis and MR. Pathological findings of thrombi in LAA were compared with clinical features, including history of valvular diseases and embolism, and findings of echocardiography. Results were analyzed using chi2 test, Fisher exact method, or Welch t test. RESULTS: Two types of mural thrombi were found in LAA: membranous (M)-thrombi and polypoid-shape (P)-thrombi. M-thrombi were found on LAA endocardium in 48 (86%) patients. All of the P-thrombi were observed on preexisting M-thrombi. More patients showed thrombi in the LAA orifice than in the tip (P < .001), especially in cases of MR (21 patients; P < .01). By echocardiography, MR flow was classified into 3 directions: toward the roof, anteroseptal, or posterolateral wall of the left atrium. Patients with MR jet flow against the posterolateral wall near the LAA entrance had a higher risk of LAA thrombi (P = .007). CONCLUSIONS: Instability of M-thrombi, including surface rupture before complete organization, relates to P-thrombi formation that results in high incidence of embolism in AF patients.

Superiority of the extracellular volume fraction over the myocardial T1 value for the assessment of myocardial fibrosis in patients with non-ischemic cardiomyopathy.

PURPOSE: This study aimed to assess the efficacies of the myocardial T1 value and the extracellular volume fraction (ECV) for determining the severity of myocardial fibrosis in patients with non-ischemic cardiomyopathy. MATERIALS AND METHODS: Myocardial fibrosis is considered the most important indicator of cardiac damage associated with non-ischemic cardiomyopathy. Recently, modified Look-Locker inversion recovery imaging (MOLLI) has been used for T1 mapping and measurement of the ECV for the assessment of myocardial fibrosis. The present study included 22 patients (mean age, 61.5±12.7; 21 male) with non-ischemic heart failure. Motion corrected myocardial T1 mapping was automatically performed using a MOLLI sequence, and the ECV was estimated from the pre- and post-contrast blood and myocardial T1 values corrected for the hematocrit level. All endomyocardial biopsy specimens were obtained from the inferoposterior left ventricular wall. The percentage of myocardial fibrosis (%F) was determined after Elastica Masson-Goldner staining as follows: (fibrosis area/[fibrosis area+myocardial area])×100. RESULTS: No correlation was noted between the %F and the pre- (r=0.290, p=0.191) or post-contrast T1 values (r=-0.190, p=0.398); however, a significant correlation was noted between the %F and ECV (r=0.750, p<0.001). CONCLUSIONS: In this study, the ECV reflected the extent of myocardial fibrosis, but the pre- and post-contrast T1 values did not. The ECV may be used to estimate the severity of myocardial fibrosis in patients with non-ischemic cardiomyopathy.

Autophagic vacuoles in cardiomyocytes of dilated cardiomyopathy with initially decompensated heart failure predict improved prognosis.

Autophagy is a process of bulk protein degradation and organelle turnover, and is a current therapeutic target in several diseases. The present study aimed to clarify the significance of myocardial autophagy of patients with dilated cardiomyopathy (DCM). Left ventricular endomyocardial biopsy was performed in 250 consecutive patients with DCM (54.9±13.9 years; male, 79%), initially presenting with decompensated heart failure (HF). The association of these findings with HF mortality or recurrence was examined. Myofilament changes, which are apparent in the degenerated cardiomyocytes of DCM, were recognized in 164 patients (66%), and autophagic vacuoles in cardiomyocytes were identified in or near the area of myofilament changes in 86 patients (34%). Morphometrically, fibrosis (odds ratio [OR], 0.96; 95% confidence interval [CI], 0.93 to 0.99) and mitochondrial abnormality (OR, 2.24; 95% CI, 1.23 to 4.08) were independently related with autophagic vacuoles. During the follow-up period of 4.9±3.9 y, 24 patients (10%) died, including 10 (4%) who died of HF, and 67 (27%) were readmitted for HF recurrence. Multivariate analysis identified a family history of DCM (hazard ratio [HR], 2.117; 95% CI, 1.199 to 3.738), hemoglobin level (HR, 0.845; 95% CI, 0.749 to 0.953), myofilament changes (HR, 13.525; 95% CI, 5.340 to 34.255), and autophagic vacuoles (HR, 0.214; 95% CI, 0.114 to 0.400) as independent predictors of death or readmission due to HF recurrence. In conclusion, autophagic vacuoles in cardiomyocytes are associated with a better HF prognosis in patients with DCM, suggesting autophagy may play a role in the prevention of myocardial degeneration.

Myocardial alterations and clinical implications associated with recovery of cardiac function in dilated cardiomyopathy with obesity.

BACKGROUND: Obesity is associated with an increased risk of heart failure (HF) but the relationship between changes in cardiac function and the specific pathological features of dilated cardiomyopathy (DCM) with obesity, remains unknown. METHODS: Endomyocardial biopsies from the left ventricle (LV) were obtained from 50 patients with DCM, at the first-onset of decompensated HF. Thirty patients were obese (obese-group: body mass index >30 kg/m(2)) and 20 were non-obese (lean-group). Clinical data were acquired at the admission, after one month and one year. RESULTS: The obese-group had higher systolic blood pressure (142.8 ± 33.9 vs 113.6 ± 18.7 mm Hg; p<0.001) and serum troponin-T level (0.049 ± 0.07 vs 0.020 ± 0.03 ng/mL; p=0.022) than the lean-group. LV ejection fraction (LVEF) was not significantly different between groups, but after one year the obese-group had an improved LVEF (57.0 ± 11.4 vs 44.3 ± 17.1; p=0.003). Light microscopy revealed that the obese-group had larger cardiomyocytes (17.2 ± 1.7 vs 16.4 ± 1.4 µm; p=0.033) and less myofilament lysis (37 vs 75%; p=0.008) with a higher density of lipid droplets (1.93 ± 0.8 vs 0.94 ± 0.7 /µm(2); p<0.001). Multivariate regression analysis revealed that independent predictors of LVEF improvement after 12 months were diuretics use, nuclear diameter, and absence of myofilament lysis (p=0.024, 0.012 and 0.028, respectively). CONCLUSIONS: Cardiac function in most patients with DCM with obesity is reversible and myocardial structural changes are trivial even at the ultrastructural level.

Coincidence of multiple endocrine neoplasia type 2A with acromegaly.

Medullary thyroid carcinoma (MTC) occurs as a part of multiple endocrine neoplasia (MEN) type 2. Acromegaly, a pituitary adenoma, occurs as a part of MEN1. Rarely, MEN2 and MEN1 coexist in a single patient simultaneously. A 40-year-old man with a history of pituitary adenomectomy for acromegaly had a surgical resection of thyroid carcinoma clinically diagnosed as MTC. His mother, who had MTC and pheochromocytoma, had a germline mutation in the RET gene that could cause the subtype, MEN2A. Identification of gene mutations in RET and MEN1 were examined in the subject. The resected tumor was pathologically diagnosed as MTC. Genomic examinations revealed the RET mutation C634F, which was identical to the mutation of his mother, but no MEN1 gene mutation was found. Although the simultaneous occurrence of both MEN2A and sporadic acromegaly may be accidental, there is evidence to suggest a genetic interaction between MEN2 and acromegaly.

Effects of long-term treatment for obstructive sleep apnea on pulse wave velocity.

Continuous positive airway pressure (CPAP) treatment improves endothelial function and sympathetic activity in patients with obstructive sleep apnea (OSA). However, the long-term effects of CPAP on pulse wave velocity (PWV), which reflects arterial stiffness that is associated with cardiovascular events, have not been evaluated in OSA patients with or without hypertension (HT). In this study, 212 male OSA patients who had been receiving CPAP treatment for 2 years and were divided into two groups, those with HT (n=114) and those without (n=98), were studied. In both HT and normotensive (NT) patients, PWV decreased significantly over the first 6 months of treatment (P=0.005 and 0.010, respectively), before increasing gradually from 6 to 24 months. Body mass index (BMI), body weight, heart rate (HR), systolic blood pressure (SBP) and diastolic blood pressure (DBP) levels decreased significantly in the HT group over the 2 years of CPAP treatment (P<0.001 for all). In contrast, only HR decreased significantly in the NT group over the 2 years of treatment (P<0.001). Multivariate regression analysis revealed that age (P=0.008), decreases in DBP (P<0.001) and HR (P<0.001) and higher initial levels of serum high-density lipoprotein-cholesterol (P=0.040) were independent factors related to changes in PWV over the 2 years of CPAP treatment in all patients. In conclusion, we found a significant decrease in PWV in both NT and HT patients after 6 months of CPAP treatment. In HT patients, long-term CPAP treatment significantly decreases blood pressure, which may contribute to explain the PWV improvement.