Electrical Ventricular Remodeling in Dilated Cardiomyopathy

Cardiac arrhythmias during and after thoracic irradiation for malignancies

BACKGROUND

Cardiac arrhythmia has been reported as a significant complication of thoracic radiotherapy. Both bradyarrhythmias and tachyarrhythmias have been reported, highlighting the arrhythmia-modulating potential of radiation in certain oncologic therapies. This study aimed to analyse the arrhythmic burden in patients with cardiac implantable electrical devices (CIEDs) undergoing thoracic irradiation, examining both immediate effects of radiotherapy and long-term sequelae post-therapy.

METHODS AND RESULTS

A retrospective cohort study was conducted involving patients with CIEDs who received thoracic radiotherapy between January 2012 and December 2022. Two distinct analyses were performed involving (1) daily CIED follow-ups during radiotherapy and (2) long-term arrhythmic outcomes post-therapy. For long-term outcomes, Patients were matched in a 1:2 ratio with non-irradiated controls based on age, sex, cardiovascular risk factors, cardiac disease, and beta-blocker use. Statistical analyses included negative binomial regression and propensity score matching. A total of 186 patients underwent daily CIED monitoring during radiotherapy, with 79 receiving thoracic irradiation. Thoracic irradiation was negatively associated with atrial arrhythmia (OR 0.11 [0.02;0.70, 95% CI], adjusted p = 0.0498) and there was a tendency towards less ventricular events (OR 0.14 [0.02;1.41, 95% CI], adjusted p = 0.3572) during radiotherapy in a univariate regression analysis. This association was not significant in the multivariate (OR 0.44 [0.10;1.80, 95%-CI], p = 0.16) model including a history of atrial fibrillation, diabetes and beta-blocker use. Coronary artery disease was associated with an increase in atrial and ventricular arrhythmia. For the long-term analysis, 122 patients were followed up after thoracic (N = 33) and non-thoracic radiation (N = 89) and compared to 244 matched controls drawn from approximately 10.000 CIED-patients. There was no significant increase in arrhythmic events compared to controls over a median follow-up of 6.6 months. A previous history of ventricular or atrial arrhythmic events was the strongest predictor for events during the follow-up.

CONCLUSION

Thoracic radiotherapy can be safely administered in patients with CIEDs. However, patients with a history of arrhythmia are more prone to arrhythmic events during and after radiation. These findings highlight the need for personalized arrhythmia management strategies and further research to understand the mechanisms underlying the antiarrhythmic effects of thoracic radiation.

MicroRNA‑378: An important player in cardiovascular diseases (Review)

Cardiovascular disease (CVD) is a common chronic clinical condition and is the main cause of death in humans worldwide. Understanding the genetic and molecular mechanisms involved in the development of CVD is essential to develop effective prevention strategies and therapeutic measures. An increasing number of CVD‑related genetic studies have been conducted, including those on the potential roles of microRNAs (miRs). These studies have demonstrated that miR‑378 is involved in the pathological processes of CVD, including those of myocardial infarction, heart failure and coronary heart disease. Despite the potential importance of miR‑378 CVD, a comprehensive summary of the related literature is lacking. Thus, the present review aimed to summarize the findings of previous studies on the roles and mechanisms of miR‑378 in a variety of CVDs and provide an up‑to date basis for further r research targeting the prevention and treatment of CVDs.

Genome-wide association study of dilated cardiomyopathy-induced heart failure associated with renal insufficiency in a Chinese population

BACKGROUND

As it is unclear whether there is genetic susceptibility to cardiorenal syndrome (CRS), we conducted a genome-wide association study of dilated cardiomyopathy (DCM)-induced heart failure (HF) associated with renal insufficiency (RI) in a Chinese population to identify putative susceptibility variants and culprit genes.

METHODS

A total of 99 Han Chinese patients with DCM-induced chronic HF were selected and divided into one of three groups, namely, HF with normal renal function (Group 1), HF with mild RI (Group 2) and HF with moderate to severe RI (Group 3). Genomic DNA was extracted from each subject for genotyping.

RESULTS

According to Gene Ontology (GO) function and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis, top 10 lists of molecular function, cell composition and biological process of differential target genes and 15 signalling pathways were discriminated among the three groups. Additionally, sequencing results identified 26 significantly different single-nucleotide polymorphisms (SNPs) in the 15 signalling pathways, including three SNPs (rs57938337, rs6683225 and rs6692782) in ryanodine receptor 2 (RYR2) and two SNPs (rs12439006 and rs16958069) in RYR3. The genotype and allele frequencies of the five SNPs in RYR2 and RYR3 were significantly differential between HF (Group 1) and CRS (Group 2 + 3) patients.

CONCLUSION

Twenty-six significantly different SNP loci in 17 genes of the 15 KEGG pathways were found in the three patient groups. Among these variants, rs57938337, rs6683225 and rs6692782 in RYR2 and rs12439006 and rs16958069 in RYR3 are associated with RI in Han Chinese patients with heart failure, suggesting that these variants may be used to identify patients susceptible to CRS in the future.

A Rare Case of Coexisting Mutation in Desmin and Thioredoxin Reductase 2 Genes Causing Dilated Cardiomyopathy

Desmin (DES) maintains the overall structure of cardiomyocytes and cytoskeletal organization within striated muscle cells. Mitochondrial thioredoxin reductase 2 (TXNRD-2) is essential for mitochondrial oxygen radical scavenging. We describe a rare case of dilated cardiomyopathy (DCM) in an 18-year-old female with a heterozygous mutation involving both DES and TXNRD-2 genes.

Simple screening model based on electrocardiogram for patients with dilated cardiomyopathy

Dilated cardiomyopathy (DCM) is one of the most common causes of heart failure. Therefore, screening and early diagnosis of potential DCM patients is beneficial. Electrocardiogram (ECG) can be an inexpensive and easily available screening tool. We aimed to construct a simple screening model for DCM based on electrocardiogram. In this retrospective observational study, we consecutively enrolled 117 DCM patients between July 1, 2016 and July 1, 2021 as the DCM group, while 117 patients hospitalized in the same period with normal echocardiography and ECG were selected as the non-DCM group. Patients were randomly assigned to the training and validation sets at 8:2. ECG parameters of left ventricular related leads were exacted. Logistic regression was performed to evaluate screening indicators of ECG parameters and a nomogram was conducted. The screening ability of the model was evaluated using receiver operating characteristic analysis. Furthermore, the nomogram was assessed using calibration curve and decision curve analysis. Screening indicators included in the nomogram were the amplitude of S wave in V1 and V3 leads, the amplitude of R wave in aVF and V6 leads, and PR interval. The nomogram performed satisfactory discrimination in the training (area under the receiver operating characteristic curve = 0.904) and validation (area under the receiver operating characteristic curve = 0.878) sets and good calibration (Hosmer-Lemeshow P = .066). Decision curve analysis demonstrated the model can generate a net benefit of 0.33 when the threshold probability was 0.543. The nomogram based on electrocardiogram is a simple and practical screening tool for potential DCM patients.

Identification of BMP10 as a Novel Gene Contributing to Dilated Cardiomyopathy

Dilated cardiomyopathy (DCM), characterized by left ventricular or biventricular enlargement with systolic dysfunction, is the most common type of cardiac muscle disease. It is a major cause of congestive heart failure and the most frequent indication for heart transplantation. Aggregating evidence has convincingly demonstrated that DCM has an underlying genetic basis, though the genetic defects responsible for DCM in a larger proportion of cases remain elusive, motivating the ongoing research for new DCM-causative genes. In the current investigation, a multigenerational family affected with autosomal-dominant DCM was recruited from the Chinese Han population. By whole-exome sequencing and Sanger sequencing analyses of the DNAs from the family members, a new BMP10 variation, NM_014482.3:c.166C > T;p.(Gln56*), was discovered and verified to be in co-segregation with the DCM phenotype in the entire family. The heterozygous BMP10 variant was not detected in 268 healthy volunteers enrolled as control subjects. The functional measurement via dual-luciferase reporter assay revealed that Gln56*-mutant BMP10 lost the ability to transactivate its target genes NKX2.5 and TBX20, two genes that had been causally linked to DCM. The findings strongly indicate BMP10 as a new gene contributing to DCM in humans and support BMP10 haploinsufficiency as an alternative pathogenic mechanism underpinning DCM, implying potential implications for the early genetic diagnosis and precision prophylaxis of DCM.

Electrical Remodelling in Cardiac Disease

The human heart responds to various diseases with structural, mechanical, and electrical remodelling processes [...].

Impact of myeloid differentiation protein 1 on cardiovascular disease

Cardiovascular disease remains the leading cause of disability and mortality worldwide and a significant global burden. Many lines of evidence suggest complex remodeling responses to cardiovascular disease, such as myocardial ischemia, hypertension and valve disease, which lead to poor clinical outcomes, including heart failure, arrhythmia and sudden cardiac death (SCD). The mechanisms underlying cardiac remodeling are closely related to reactive oxygen species (ROS) and inflammation. Myeloid differentiation protein 1 (MD1) is a secreted glycoprotein known as lymphocyte antigen 86. The complex of MD1 and radioprotective 105 (RP105) is an important regulator of inflammation and is involved in the modulation of vascular remodeling and atherosclerotic plaque development. A recent study suggested that the expression of MD1 in hypertrophic cardiomyopathy (HCM) patients is decreased compared with that in donor hearts. Therefore, MD1 may play an important role in the pathological processes of cardiovascular disease and have potential clinical value. Here, this review aims to discuss the current knowledge regarding the role of MD1 in the regulation of cardiac pathophysiology.