Background: Truncating variants in the TTN gene (TTNtv) are the commonest cause of heritable dilated cardiomyopathy. This study aimed to study the phenotypes and outcomes of TTNtv carriers. Methods: Five hundred thirty-seven individuals (61% men; 317 probands) with TTNtv were recruited in 14 centers (372 [69%] with baseline left ventricular systolic dysfunction [LVSD]). Baseline and longitudinal clinical data were obtained. The primary end point was a composite of malignant ventricular arrhythmia and end-stage heart failure. The secondary end point was left ventricular reverse remodeling (left ventricular ejection fraction increase by ≥10% or normalization to ≥50%). Results: Median follow-up was 49 (18–105) months. Men developed LVSD more frequently and earlier than women (45±14 versus 49±16 years, respectively; P =0.04). By final evaluation, 31%, 45%, and 56% had atrial fibrillation, frequent ventricular ectopy, and nonsustained ventricular tachycardia, respectively. Seventy-six (14.2%) individuals reached the primary end point (52 [68%] end-stage heart failure events, 24 [32%] malignant ventricular arrhythmia events). Malignant ventricular arrhythmia end points most commonly occurred in patients with severe LVSD. Male sex (hazard ratio, 1.89 [95% CI, 1.04–3.44]; P =0.04) and left ventricular ejection fraction (per 10% decrement from left ventricular ejection fraction, 50%; hazard ratio, 1.63 [95% CI, 1.30–2.04]; P <0.001) were independent predictors of the primary end point. Two hundred seven of 300 (69%) patients with LVSD had evidence of left ventricular reverse remodeling. In a subgroup of 29 of 74 (39%) patients with initial left ventricular reverse remodeling, there was a subsequent left ventricular ejection fraction decrement. TTNtv location was not associated with statistically significant differences in baseline clinical characteristics, left ventricular reverse remodeling, or outcomes on multivariable analysis ( P =0.07). Conclusions: TTNtv is characterized by frequent arrhythmia, but malignant ventricular arrhythmias are most commonly associated with severe LVSD. Male sex and LVSD are independent predictors of outcomes. Mutation location does not impact clinical phenotype or outcomes.

The aim of this study was to determine the frequency of heterozygous truncating ALPK3 variants (ALPK3tv) in patients with hypertrophic cardiomyopathy (HCM) and confirm their pathogenicity using burden testing in independent cohorts and family co-segregation studies. In a discovery cohort of 770 index patients with HCM, 12 (1.56%) were heterozygous for ALPK3tv [odds ratio(OR) 16.11, 95% confidence interval (CI) 7.94–30.02, P = 8.05e−11] compared to the Genome Aggregation Database (gnomAD) population. In a validation cohort of 2047 HCM probands, 32 (1.56%) carried heterozygous ALPK3tv (OR 16.17, 95% CI 10.31–24.87, P < 2.2e−16, compared to gnomAD). Combined logarithm of odds score in seven families with ALPK3tv was 2.99. In comparison with a cohort of genotyped patients with HCM (n = 1679) with and without pathogenic sarcomere gene variants (SP+ and SP−), ALPK3tv carriers had a higher prevalence of apical/concentric patterns of hypertrophy (60%, P < 0.001) and of a short PR interval (10%, P = 0.009). Age at diagnosis and maximum left ventricular wall thickness were similar to SP− and left ventricular systolic impairment (6%) and non-sustained ventricular tachycardia (31%) at baseline similar to SP+. After 5.3 ± 5.7 years, 4 (9%) patients with ALPK3tv died of heart failure or had cardiac transplantation (log-rank P = 0.012 vs. SP− and P = 0.425 vs. SP+). Imaging and histopathology showed extensive myocardial fibrosis and myocyte vacuolation. Heterozygous ALPK3tv are pathogenic and segregate with a characteristic HCM phenotype. Truncating variants in ALPK3 are a cause of 1–2% of autosomal dominant hypertrophic cardiomyopathy and are associated with a phenotype characterized by extensive fibrosis and a predominantly concentric or apical pattern of left ventricular hypertrophy without left ventricular outflow tract obstruction. (A) Main phenotype characteristics and outcomes. ALPK3tv, alpha-protein kinase 3-truncating variants; CK, creatine kinase; HCM, hypertrophic cardiomyopathy; ICD, implantable cardioverter–defibrillator; LVH, left ventricular hypertrophy; LVSD, left ventricular systolic dysfunction; SCD, sudden cardiac death. (B) Cardiac magnetic resonance imaging showing the prevalent phenotype of severe mid to apical hypertrophy and extensive late gadolinium enhancement in three patients. Left to right: 4-chamber view end-diastole cine image, 4-chamber view late gadolinium enhancement image, short axis late gadolinium enhancement image. (C) Kaplan–Meier analysis comparing incidence of an outcome of heart failure death and transplant between ALP3tv patients, sarcomere positive and sarcomere negative. SARC+: sarcomere positive; SARC−: sarcomere negative.

Dilated cardiomyopathy (DCM) is the third most common cause of heart failure. The multidisciplinary nature of testing — involving genetics, imaging, or cardiovascular techniques — makes its diagnosis challenging. Novel and reliable biomarkers are needed for early identification and tailored personalized management. Peripheral circular RNAs (circRNAs), a leading research topic, remain mostly unexplored in DCM. We aimed to assess whether peripheral circRNAs are expressed differentially among etiology-based DCM. The study was based on a case–control multicentric study. We enrolled 130 subjects: healthy controls (n = 20), idiopathic DCM (n = 30), ischemic DCM (n = 20), and familial DCM patients which included pathogen variants of (i) LMNA gene (n = 30) and (ii) BCL2-associated athanogene 3 (BAG3) gene (n = 30). Differentially expressed circRNAs were analyzed in plasma samples by quantitative RT-PCR and correlated to relevant systolic and diastolic parameters. The pathophysiological implications were explored through bioinformatics tools. Four circRNAs were overexpressed compared to controls: hsa_circ_0003258, hsa_circ_0051238, and hsa_circ_0051239 in LMNA-related DCM and hsa_circ_0089762 in the ischemic DCM cohort. The obtained areas under the curve confirm the discriminative capacity of circRNAs. The circRNAs correlated with some diastolic and systolic echocardiographic parameters with notable diagnostic potential in DCM. Circulating circRNAs may be helpful for the etiology-based diagnosis of DCM as a non-invasive biomarker. Key messages: The limitations of cardiac diagnostic imaging and the absence of a robust biomarker reveal the need for a diagnostic tool for dilated cardiomyopathy (DCM). The circular RNA (circRNA) expression pattern is paramount for categorizing the DCM etiologies. Our peripheral circRNAs fingerprint discriminates between various among etiology-based DCM and correlates with some echocardiographic parameters. We provide a potential non-invasive biomarker for the etiology-based diagnosis of LMNA-related DCM and ischemic DCM.

Treatment of heart failure and reduced ejection fraction (HFrEF) using angiotensin receptor-neprilysin inhibitor demonstrates beneficial effects on cardiac remodeling (CR). We assessed the impact of sacubitril/valsartan on the concentrations of HF biomarkers in relation to parameters of CR using imaging techniques in patients with HFrEF. In a prospective single-center open-label study, 68 patients with symptomatic HFrEF were treated with sacubitril/valsartan and followed-up every three months for 12 months. Soluble suppression of tumorigenicity 2 (sST2), N-terminal pro-B-type natriuretic peptide (NT-proBNP), and high-sensitivity cardiac troponin I (hs-cTnI) were measured in blood samples. Additionally, echocardiography and cardiac magnetic resonance imaging (cMRI) were performed to assess heart structural and functional changes. Following treatment initiation, follow-up visits revealed an improved NYHA functional class in these patients, alongside significant decreases in all circulating biomarkers, increases in left ventricular ejection fraction (LVEF), and reductions in volume- and diameter-related LV parameters. Sustained gradual decreases in sST2 concentrations over time correlated with NT-proBNP concentrations (rho=+0.26, P < 0.001). Both biomarkers were inversely correlated with LVEF, and positively correlated with volume- and diameter-related LV parameters from echocardiography and cMRI. However, NT-proBNP concentrations exhibited stronger correlations with these LV parameters and were associated with the number of LV segments showing fibrosis, unlike sST2. Sacubitril/valsartan treatment in HFrEF leads to reduced sST2 and NT-proBNP concentrations with distinct decreasing curves, which are linked to reverse CR through LV-related parameters. In contrast to sST2, NT-proBNP is also associated with fibrosis, suggesting that both biomarkers unveil distinct mechanisms during CR in patients treated with sacubitril/valsartan.

Cardiovascular diseases (CVDs) remain the leading cause of morbidity and mortality worldwide. Increasing evidence indicates that sex differences significantly influence the development, progression, and outcomes of CVDs. Recent advances have highlighted the central role of mitochondria, not only as cellular energy hubs but also as key regulators of oxidative stress, inflammation, and apoptosis, in mediating sex-specific cardiovascular responses. This review explores sexual dimorphism in cardiovascular disease, focusing on the interplay between mitochondrial function and sex hormones in cardiovascular tissues. We summarize current evidence on the molecular, hormonal, and cellular mechanisms contributing to sex-based disparities in cardiovascular outcomes. Preclinical studies suggest that female cardiac mitochondria may exhibit greater antioxidant capacity and produce fewer reactive oxygen species than male mitochondria, contributing to enhanced cardioprotection. Estrogen has been shown to influence mitochondrial bioenergetics and gene expression, affecting vascular tone, inflammation, and cardiac remodelling, whereas the role of testosterone remains less well defined. Additionally, sex-specific mitochondrial signalling responses have been reported under cardiac stress conditions, which may underlie differences in disease presentation and progression. A better understanding of how sex modulates mitochondrial function could improve risk stratification and support the development of personalized prevention and treatment strategies. Further research is needed to translate these mechanistic insights into clinical practice.