Makoto Hoyano

Thromboembolism in Takotsubo cardiomyopathy

BACKGROUND Most patients with Takotsubo cardiomyopathy show a favorable outcome. Although several complications have been reported, the frequency of thromboembolism has not been clarified. METHODS Clinical characteristics and complications of 21 consecutive patients (18 female, aged 72 years) with Takotsubo cardiomyopathy during the past 9 years were investigated. RESULTS The most major complication was heart failure (52%). Thromboembolism was found in 3 patients (14%) and this was the second most frequent cardiovascular complication. One of the 3 patients showed left ventricular thrombus and the other 2 experienced cardioembolic stroke. All 3 patients visited the emergency department more than 48 h after initial chest pain occurred. CONCLUSIONS This study indicates that thromboembolism is a common complication in the acute phase of Takotsubo cardiomyopathy, and anticoagulation therapy should be performed in all patients until wall motion abnormalities improve. Takotsubo cardiomyopathy should be considered one of the important causes of cardioembolic stroke.

Role of mineralocorticoid receptor on atrial structural remodeling and inducibility of atrial fibrillation in hypertensive rats

Hypertension is well known to increase atrial fibrillation (AF) and the development of AF is associated with atrial chamber remodeling. Although mineralocorticoid receptor (MR) inhibition provides cardiovascular protection, the role of MR on atrial structural remodeling and inducibility of AF in hypertension remains unclear. Here, we investigated roles of the MR on atrial structural remodeling and inducibility of AF in hypertensive rats by using MR antagonist eplerenone (EPL). Dahl salt-sensitive (DS) rats were fed a normal-salt or a high-salt (HS) diet from 7 weeks, and a non-antihypertensive dose of EPL or vehicle was administrated from 13 weeks, at which time myocytes hypertrophy, interstitial fibrosis in the atrium and AF inducibility had increased, until 20 weeks. There was no significant difference in systolic blood pressure between DS+HS (186±4 mm Hg) and DS+HS+EPL (184±5 mm Hg) at 20 weeks. Burst atrial pacing demonstrated decreased AF inducibility in DS+HS+EPL (0 of 10) compared with DS+HS (7 of 10). Fibrosis and myocytes hypertrophy in the atrium were decreased in DS+HS+EPL with the reduction of atrial inflammatory cytokines. These beneficial effects of EPL were associated with less atrial oxidative stress, as assessed by 4-hydroxy-2-nonenal staining, and reduced activation of the Rho GTPase Rac1 in the atrium. Thus, MR has important roles in atrial structural remodeling and AF inducibility in Dahl rats. The effects of MR are associated, at least in part, with activation of Rac1-oxidative stress/inflammatory axis.

Therapeutic Role of Pericardiocentesis for Acute Necrotizing Eosinophilic Myocarditis With Cardiac Tamponade

We describe a patient with acute necrotizing eosinophilic myocarditis who recovered rapidly after pericardial drainage and without corticosteroid therapy. The 25-year- old man was referred to our hospital with suspected acute myocardial infarction on the basis of severe epigastralgia, abnormal Q waves and ST elevation on electrocardiography, and an increase in cardiac enzymes. Echocardiography disclosed pericardial effusion that compressed the right ventricle, left ventricular dysfunction in conjunction with posterolateral hypokinesis, and a thickened ventricular wall but no mural thrombus. The eosinophil count in the peripheral blood was slightly increased. Coronary angiography showed normal arteries and thus prompted an endomyocardial biopsy. The patient was transferred to the intensive care unit with a clinical diagnosis of myocarditis associated with cardiac tamponade. Emergency pericardiocentesis relieved symptoms immediately. The cells in the pericardial effusion were mainly eosinophils; interleukin 5 and interleukin 13 levels were predominantly elevated, and the effusion was drained for 5 days. The biopsy specimen revealed necrotizing eosinophilic myocarditis. Left ventricular function recovered within a week without corticosteroid therapy. No relapse was observed as of 8 months after diagnosis.

Inducibility of atrial fibrillation depends not on inflammation but on atrial structural remodeling in rat experimental autoimmune myocarditis

INTRODUCTION There is increasing evidence to support a link between inflammation and atrial fibrillation (AF). However, the role of inflammation on new-onset AF is still to be elucidated. METHODS Rats underwent induction of experimental autoimmune myocarditis (EAM). Atrial structural change was evaluated by echocardiography and histological analysis. Electrophysiological data and the in vivo atrial response to burst atrial pacing were evaluated in the acute (2 weeks after EAM induction) and chronic phases (8 weeks after induction). In addition, atrial pacing after 2, 4, and 6 h after lipopolysaccharide (LPS) infusion, when the expression of gap junctions was modified, were challenged with young healthy rats. RESULTS AF was induced in 11 of 15 chronic phase EAM rats but not in either acute phase EAM rats or LPS infusion rats (P<.01). Echocardiography showed dilatation of both atrium and ventricle and a decrease in the ejection fraction in the chronic phase. Histology revealed severe inflammatory lesions only in the acute phase. Interstitial atrial fibrosis as well as the area of atrial myocyte increased in the chronic phase but not in the acute phase. CONCLUSIONS AF could be induced in the chronic phase of myocarditis rats, but not in the acute phase of myocarditis rats or in rats with LPS infusion. Acute inflammation per se did not increase the occurrence of AF induction. Atrial structural remodeling caused by inflammation and hemodynamic effects is necessary to induce AF.

Sulfated Polysaccharide Fucoidan Ameliorates Experimental Autoimmune Myocarditis in Rats

Homing of cardiac myosin-specific CD4-positive T cells into the myocardium is the initial pathologic event of experimental autoimmune myocarditis (EAM). Subsequently, various bystander inflammatory cells are recruited into the myocardium crossing vascular endothelial cell walls. Sulfated polysaccharide fucoidan binds selectin nonselectively and blocks its function. Therefore, this study was designed to evaluate whether in vivo fucoidan treatment can improve EAM. A 21-day infusion of physiological saline or fucoidan was administrated intraperitoneally to the rats with sham operation (sham-saline, n = 5; sham-fucoidan, n = 6) or those with cardiac myosin injection (EAM-saline, n = 10; EAM-fucoidan, n = 10). After 3 weeks, fucoidan treatment improved left ventricular ejection fraction (79.04 ± 2.81 vs 65.94% ± 3.22%; P < .01 vs EAM-saline) with a reduced ratio of heart weight to body weight (4.016 ± 0.239 vs 4.975 ± 0.252 mg/g; P < .05 vs EAM-saline) in EAM. Furthermore, fucoidan treatment decreased serum levels of BNP (292.0 ± 53.4 vs 507.4 ± 89.2 ng/mL; P < .05 vs EAM-saline) and the myocarditis area (31.66 ± 1.53 vs 42.51% ± 3.24%; P < .01 vs EAM-saline) in EAM. These beneficial effects of fucoidan were accompanied by inhibition of both macrophage and CD4-positive T-cell infiltration into the myocardium. Fucoidan, a nonselective selectin blocker, attenuates the progression of EAM. This observation may be explained, at least in part, by blocking the extravasation of inflammatory cells into the myocardium.

Long-term carperitide treatment attenuates left ventricular remodeling in rats with heart failure after autoimmune myocarditis.

The effect of carperitide, recombinant human atrial natriuretic peptide, on chronic heart failure (HF) has not been clarified. We investigated the beneficial effects of chronic carperitide treatment in rats with HF after experimental autoimmune myocarditis. A 28-day infusion of carperitide (n = 14) or vehicle (n = 14) was administrated to the rats 4 weeks after experimental autoimmune myocarditis induction. After 4 weeks, the myocardial levels of cyclic guanosine monophosphate (cGMP), left ventricular function, myocyte hypertrophy, interstitial fibrosis, myocardial capillary vessel density, and activity of one prominent substrate of cGMP, vasodilator-stimulated phosphoprotein (VASP) that may enhance angiogenesis, were measured. Carperitide treatment increased the myocardial levels of cGMP and attenuated the functional severity along with a decreased myocyte cross-sectional area, interstitial fibrosis, and an increased capillary to myocyte ratio. Furthermore, carperitide treatment enhanced the phosphorylation of VASP at Ser239, which was preferentially phosphorylated by cGMP-dependent protein kinase but not Ser157, which was preferentially phosphorylated by cyclic adenosine monophosphate-dependent protein kinase. Long-term carperitide treatment attenuates ventricular remodeling and ameliorates the progression of chronic HF. The effects of carperitide treatment are associated with increased neovascularization among the residual myocytes and an increase of VASP activation.

Bidirectional Shunt Trajectory in Ventricular Septal Defect With Eisenmenger’s Syndrome

Received March 19, 2018; revised manuscript received April 13, 2018; accepted April 18, 2018; released online May 25, 2018 Time for primary review: 23 days Department of Cardiovascular Biology and Medicine (H.K., T. Kashimura, N.K., Y.I., T.T., T. Okubo, M.H., T.Y., T. Ozawa, K.O., T.M.), Department of Advanced Cardiopulmonary Vascular Therapeutics (T. Kashimura, M.H.), Department of Radiology (Y.H., T. Kanazawa), Niigata University Graduate School of Medical and Dental Sciences, Niigata; Division of Cardiology, Nagaoka Red-Cross Hospital, Nagaoka (T.F.), Japan Mailing address: Takeshi Kashimura, MD, PhD, Department of Cardiovascular Biology and Medicine, Niigata University Graduate School of Medical and Dental Sciences, 1-754 Asahimachi, Niigata 951-8510, Japan. E-mail: kashi@med.niigata-u.ac.jp ISSN-1346-9843 All rights are reserved to the Japanese Circulation Society. For permissions, please e-mail: cj@j-circ.or.jp Bidirectional Shunt Trajectory in Ventricular Septal Defect With Eisenmenger’s Syndrome