Impaired right and left ventricular function and relaxation induced by pulmonary regurgitation are not reversed by tardive antifibrosis treatment

Adverse remodelling in tetralogy of Fallot: From risk factors to imaging analysis and future perspectives

Although contemporary outcomes of initial surgical repair of tetralogy of Fallot (TOF) are excellent, the survival of adult patients remains significantly lower than that of the normal population due to the high incidence of heart failure, ventricular arrhythmias, and sudden cardiac death. The underlying mechanisms are only partially understood but involve an adverse biventricular response, so-called remodelling, to key stressors such as right ventricular (RV) pressure-and/or volume-overload, myocardial fibrosis, and electro-mechanical dyssynchrony. In this review, we explore risk factors and mechanisms of biventricular remodelling, from histological to electro-mechanical aspects, and the role of imaging in their assessment. We discuss unsolved challenges and future directions to better understand and treat the long-term sequelae of this complex congenital heart disease.

PR and QRS interval changes after transcatheter pulmonary valve replacement in children

BACKGROUND

Changes in PR intervals after transcatheter pulmonary valve replacement (TCPVR) have not been thoroughly evaluated in children. This study evaluated the changes in PR and QRS intervals six months after TCPVR in children with congenital heart disease.

RESULTS

This study included 41 patients who underwent TCPVR from 2010 to 2022. ECG of patients was reviewed before and six months after TCPVR, and the PR and QRS intervals were reported. Right ventricular systolic pressure (RVSP) was retrieved indirectly from echocardiography and compared pre- and 6-months after TPVR. The median age was 13 years (25th-75th percentiles: 11-16), and 61% were males. The preoperative diagnosis was tetralogy of Fallot (n = 29, 71%), transposition of great vessels (n = 4, 10%), common arterial trunk (n = 3, 7%), pulmonary valve stenosis (n = 3, 7%) and pulmonary atresia (n = 2, 5%). The Melody valve was used in 30 patients, and Edwards Sapien was used in 11 patients. RVSP was significantly reduced six months after the procedure (pre-RVSP 40 (30-55) mmHg vs. post-RVSP 25 (20-35) mmHg; P < 0.001). The PR interval was 142 (132-174) msec before TPVR and 146 (132-168) msec post-TCPVR (P = 0.442). Post-TPVR PR was positively related to the pre-PR (β: 0.79 (0.66-0.93), P < 0.001) and inversely related to the right ventricular outflow tract size (- 1.48 (- 2.76 to - 0.21), P = 0.023). The pre-TPVR QRS was 130 (102-146) msec, and the post-TPVR QRS was 136 (106-144) msec (P = 0.668).

CONCLUSIONS

In children undergoing TCPVR, the PR and QRS intervals did not change significantly during a 6-month follow-up.

The right ventricle in tetralogy of Fallot: adaptation to sequential loading

Right ventricular dysfunction is a major determinant of outcome in patients with complex congenital heart disease, as in tetralogy of Fallot. In these patients, right ventricular dysfunction emerges after initial pressure overload and hypoxemia, which is followed by chronic volume overload due to pulmonary regurgitation after corrective surgery. Myocardial adaptation and the transition to right ventricular failure remain poorly understood. Combining insights from clinical and experimental physiology and myocardial (tissue) data has identified a disease phenotype with important distinctions from other types of heart failure. This phenotype of the right ventricle in tetralogy of Fallot can be described as a syndrome of dysfunctional characteristics affecting both contraction and filling. These characteristics are the end result of several adaptation pathways of the cardiomyocytes, myocardial vasculature and extracellular matrix. As long as the long-term outcome of surgical correction of tetralogy of Fallot remains suboptimal, other treatment strategies need to be explored. Novel insights in failure of adaptation and the role of cardiomyocyte proliferation might provide targets for treatment of the (dysfunctional) right ventricle under stress.

Losartan attenuates acetic acid enema-induced visceral hypersensitivity by inhibiting the ACE1/Ang II/AT1 receptor axis in enteric glial cells

Enteric glial cells (EGCs) play an important role in visceral hypersensitivity associated with irritable bowel syndrome (IBS). Losartan (Los) is known to reduce pain; however, its function in IBS is unclear. The present study aimed to investigate Los's therapeutic effect on visceral hypersensitivity in IBS rats. Thirty rats were randomly divided into control, acetic acid enema (AA), AA + Los low, medium and high dose groups in vivo. EGCs were treated with lipopolysaccharide (LPS) and Los in vitro. The molecular mechanisms were explored by assessing the expression of EGC activation markers, pain mediators, inflammatory factors and angiotensin-converting enzyme 1(ACE1)/angiotensin II (Ang II)/Ang II type 1 (AT1) receptor axis molecules in colon tissue and EGCs. The results showed that the rats in the AA group showed significantly higher visceral hypersensitivity than the control rats, which was alleviated by different doses of Los. The expression of GFAP, S100β, substance P (SP), calcitonin gene-related peptide (CGRP), transient receptor potential vanilloid 1 (TRPV1), tumor necrosis factor (TNF), interleukin-1β (IL-1β) and interleukin-6 (IL-6) was considerably increased in colonic tissues of AA group rats and LPS-treated EGCs compared with control rats and EGCs, and reduced by Los. In addition, Los reversed ACE1/Ang II/AT1 receptor axis upregulation in AA colon tissues and LPS-treated EGCs. These results show that Los inhibits ACE1/Ang II/AT1 receptor axis upregulation by suppressing EGC activation, resulting in reduced expression of pain mediators and inflammatory factors, thereby alleviating visceral hypersensitivity.

Rodent Models of Dilated Cardiomyopathy and Heart Failure for Translational Investigations and Therapeutic Discovery

Even with modern therapy, patients with heart failure only have a 50% five-year survival rate. To improve the development of new therapeutic strategies, preclinical models of disease are needed to properly emulate the human condition. Determining the most appropriate model represents the first key step for reliable and translatable experimental research. Rodent models of heart failure provide a strategic compromise between human in vivo similarity and the ability to perform a larger number of experiments and explore many therapeutic candidates. We herein review the currently available rodent models of heart failure, summarizing their physiopathological basis, the timeline of the development of ventricular failure, and their specific clinical features. In order to facilitate the future planning of investigations in the field of heart failure, a detailed overview of the advantages and possible drawbacks of each model is provided.

Multimodality Imaging of the Neglected Valve: Role of Echocardiography, Cardiac Magnetic Resonance and Cardiac Computed Tomography in Pulmonary Stenosis and Regurgitation

The pulmonary valve (PV) is the least imaged among the heart valves. However, pulmonary regurgitation (PR) and pulmonary stenosis (PS) can occur in a variety of patients ranging from fetuses, newborns (e.g., tetralogy of Fallot) to adults (e.g., endocarditis, carcinoid syndrome, complications of operated tetralogy of Fallot). Due to their complexity, PR and PS are studied using multimodality imaging to assess their mechanism, severity, and hemodynamic consequences. Multimodality imaging is crucial to plan the correct management and to follow up patients with pulmonary valvulopathy. Echocardiography remains the first line methodology to assess patients with PR and PS, but the information obtained with this technique are often integrated with cardiac magnetic resonance (CMR) and computed tomography (CT). This state-of-the-art review aims to provide an updated overview of the usefulness, strengths, and limits of multimodality imaging in patients with PR and PS.