Atrial cardiomyocytes contribute to the inflammatory status associated with atrial fibrillation in right heart disease.

AIMS: Right heart disease (RHD), characterized by right ventricular (RV) and atrial (RA) hypertrophy, and cardiomyocytes' (CM) dysfunctions have been described to be associated with the incidence of atrial fibrillation (AF). Right heart disease and AF have in common, an inflammatory status, but the mechanisms relating RHD, inflammation, and AF remain unclear. We hypothesized that right heart disease generates electrophysiological and morphological remodelling affecting the CM, leading to atrial inflammation and increased AF susceptibility. METHODS AND RESULTS: Pulmonary artery banding (PAB) was surgically performed (except for sham) on male Wistar rats (225-275 g) to provoke an RHD. Twenty-one days (D21) post-surgery, all rats underwent echocardiography and electrophysiological studies (EPS). Optical mapping was performed in situ, on Langendorff-perfused hearts. The contractility of freshly isolated CM was evaluated and recorded during 1 Hz pacing in vitro. Histological analyses were performed on formalin-fixed RA to assess myocardial fibrosis, connexin-43 levels, and CM morphology. Right atrial levels of selected genes and proteins were obtained by qPCR and Western blot, respectively. Pulmonary artery banding induced severe RHD identified by RV and RA hypertrophy. Pulmonary artery banding rats were significantly more susceptible to AF than sham. Compared to sham RA CM from PAB rats were significantly elongated and hypercontractile. Right atrial CM from PAB animals showed significant augmentation of mRNA and protein levels of pro-inflammatory interleukin (IL)-6 and IL1ß. Sarcoplasmic-endoplasmic reticulum Ca2+-ATPase-2a (SERCA2a) and junctophilin-2 were decreased in RA CM from PAB compared to sham rats. CONCLUSIONS: Right heart disease-induced arrhythmogenicity may occur due to dysfunctional SERCA2a and inflammatory signalling generated from injured RA CM, which leads to an increased risk of AF.

Inhibition of transglutaminase 2 (TG2) ameliorates ventricular fibrosis in isoproterenol-induced heart failure in rats.

AIMS: Transglutaminase (TG) inhibitors represent promising therapeutic interventions in cardiac fibrosis and related dysfunctions. However, it remains unknown how TG inhibition, TG2 in particular, affects the signaling systems that drive pathological fibrosis. This study aimed to examine the effect TG inhibition by cystamine on the progression of isoproterenol (ISO)-induced cardiac fibrosis and dysfunction in rats. MATERIALS AND METHODS: Cardiac fibrosis was established by intraperitoneal injection of ISO to rats (ISO group), followed by 6 weeks of cystamine injection (ISO + Cys group). The control groups were administered normal saline alone or with cystamine. Hemodynamics, lipid profile, liver enzymes, urea, and creatinine were assessed in conjunction with heart failure markers (serum NT-proANP and cTnI). Left ventricular (LV) and atrial (LA) fibrosis, total collagen content, and mRNA expression of profibrotic markers including TG2 were quantified by Masson's trichrome staining, LC-MS/MS and quantitative PCR, respectively. KEY FINDINGS: Cystamine administration to ISO rats significantly decreased diastolic and mean arterial pressures, total cholesterol, triglycerides, LDL, liver enzymes, urea, and creatinine levels, while increasing HDL. NT-proANP and cTnI serum levels remained unchanged. In LV tissues, significant reductions in ISO-induced fibrosis and elevated total collagen content were achieved after cystamine treatment, together with a reduction in TG2 concentration. Reduced mRNA expression of several profibrotic genes (COL1A1, FN1, MMP-2, CTGF, periostin, CX43) was also evidenced in LV tissues of ISO rats upon cystamine administration, whereas TGF-ß1 expression was depressed in LA tissues. Cystamine decreased TG2 mRNA expression in the LV of control rats, while LV expression of TG2 was relatively low in ISO rats irrespective of cystamine treatment. SIGNIFICANCE: TG2 inhibition by cystamine in vivo exerted cardioprotective effects against ISO-induced cardiac fibrosis in rats decreasing the LV abundance of several profibrotic markers and the content of TG2 and collagen, suggesting that TG2 pharmacological inhibition could be beneficial to alleviate cardiac fibrosis.

Comparison of Doty and McGoon techniques for surgical reconstruction of congenital supravalvular aortic stenosis.

BACKGROUND: We aimed to compare the results of two surgical methods for the treatment of congenital supravalvular aortic stenosis. METHODS: From May 2004 to January 2020, 29 patients underwent surgical repair for supravalvular aportic stenosis in a single centre. The perioperative evaluation of the patients was retrospectively reviewed. RESULTS: Fifteen (51.7%) and 14 (48.2%) patients were treated with the Doty and the McGoon methods, respectively. The median age of our cohort was 4.5 (3.0-9.9) years. Ten (34.5%) patients had Williams-Beuren syndrome, and pulmonary stenosis was observed in 12 (41.3%) patients. The median follow-up time was 2.5 (0.7-7.3) years. On follow-up, five patients had residual stenosis with the McGoon technique and one with the Doty technique (p = 0.05). One patient died early in the post-operative period in the Doty group, and three patients were re-operated on due to restenosis in the McGoon group. Freedom from re-operation in the Doty group at 1, 3, 5, and 10 years was 100%. In the McGoon group, freedom from re-operation rates at the 1-, 3-, and 7-year follow-up were 100, 88.9, and 44.4%, respectively (p = 0.08). CONCLUSION: Our results with both surgical techniques suggest that supravalvular aortic stenosis can be treated with good results. The Doty method provided better relief for the supravalvular aortic segment, considering the residual stenosis and the re-operation rates.

High incidence of fever in patients after biointegral pulmonic valved conduit implantation.

OBJECTIVE: To describe our short- and medium-term outcomes using the BioIntegral pulmonic conduit. METHODS: Between August 2018 and September 2019, the BioIntegral pulmonic valved conduit was used for right ventricular outflow tract reconstruction in 48 patients. The data were retrospectively retrieved from the patient charts. RESULTS: The median age at surgery was 36 months (interquartile range [IQR] = 18-62 months). The diagnoses were pulmonary atresia-ventricular septal defect in 28 patients, absent pulmonary valve in four patients, truncus arteriosus in six patients, TGA-VSD-PS in five patients, conduit stenosis in three patients, and left venticular outflow tract obstruction requiring a Ross operation in two patients. In the postoperative short-term follow-up, 15 patients out of 48 had a high fever. Of these, 12 patients had concomitantly elevated C-reactive protein levels. There were no patients with blood culture positivity. The median postoperative length of hospital stay was 14 days (IQR = 8-21 days). The overall mortality was 4% in two patients, one died of right ventricular failure and multiple organ failure and one died of pulmonary embolism. The two patients who died were not among the 15 patients with fever. However, four patients with fever underwent balloon angioplasty for conduit restenosis in their medium-term follow-up. CONCLUSION: There was a high incidence of fever and adverse outcomes in the short-term postoperative follow-up of patients in whom the BioIntegral pulmonic valved conduit was implanted. Caution is advisable in using these conduits until there is convincing evidence about the sterilization and storage standards of these grafts.

The choice of palliative arterial switch operation as an alternative for selected cases in a single center: Experience and mid term results.

INTRODUCTION AND OBJECTIVE: There are various management options for newborns with single ventricle physiology, ventriculoarterial discordance and subaortic stenosis, classically involving the early pulmonary banding and aortic arch repair, the restricted bulboventriculer foramen enlargement or the Norwood and the Damus-Kaye-Stansel procedures. The aim of this study is to evaluate our preferred technique and comment on the midterm results of our clinical experience with palliative arterial switch operation (pASO) for a certain subset of patients. METHOD: We hereby retrospectively evaluate the charts of patients who went through pASO, as initial palliation through Fontan pathway, starting from 2014 till today. RESULTS: Ten patients underwent an initial palliative arterial switch procedure. Eight of 10 patients survived the operation and discharged. Seven of 10 patients completed Stage II and 1 patient reached the Fontan completion stage and the other six of ten (6/10) patients are doing well and waiting for the next stage of palliation. There are two mortalities in the series (2/10) and one patient lost to follow-up (1/10). CONCLUSION: In our opinion, the pASO can be considered as an alternative palliation option for patients with single ventricle physiology, transposition of the great arteries and systemic outflow tract obstruction despite longer cross clamp times compared to other methods, but It not only preserves systolic and diastolic ventricular function, but also provides a superior anatomic arrangement for following stages.

Single-Stage Fontan Operation in a Patient With Coronary Sinus Ostium Atresia.

An eight-year-old boy with tricuspid atresia was found to have atretic coronary sinus ostium during cardiac catheterization. Single-stage extracardiac fenestrated Fontan operation was performed with surgical unroofing of the coronary sinus into the left atrium to avoid the risk of cardiac congestion.