Search Results (3,761)

Scimitar syndrome is a rare congenital form of partial anomalous pulmonary venous return characterized by right pulmonary venous drainage into the inferior vena cava, causing right-sided volume overload and increased risk of supraventricular arrhythmias, particularly in adolescents and adults. However, existing studies do not clearly describe reported arrhythmia patterns or how heart rhythm changes over time. This structured literature review aimed to characterize the reported atrial and supraventricular arrhythmias and conduction disturbances in patients with Scimitar syndrome and examine their relationship with atrial remodeling, hemodynamic burden, associated structural abnormalities, and surgical or catheter-based intervention. PubMed, Embase, Web of Science, and the Cochrane Library were searched from September 2026. Of 308 abstracts, 42 articles met the inclusion criteria (Scimitar syndrome patients, with broader PAPVR populations included as contextual evidence; literature reviews, abstract only publications, animal studies and non-English articles were excluded). Studies consistently showed that Scimitar syndrome is associated with right-sided volume overload linked to increased atrial and supraventricular arrhythmias, most commonly atrial fibrillation and flutter, with greater risk in patients with associated atrial septal defects or pulmonary hypertension. Because Scimitar syndrome can remain undiagnosed until adulthood, future studies should identify specific predictors of arrhythmia development to improve long-term electrophysiological outcomes. Full article

Atrial fibrillation (AFib) is the most prevalent sustained cardiac arrhythmia, yet most deep learning detectors are validated on a single cohort and few report uncertainty. We developed a compact 14M-parameter convolutional neural network for binary AFib classification from 10 s, 12-lead ECG at 500 Hz, trained exclusively on the HDXML dataset (67,432 ECGs; 9628 AFib) with on-the-fly augmentation for noise, drift and missing channels. Using one unchanged checkpoint, we evaluated six independently sourced public cohorts totaling over 1.25 million recordings, including MIMIC-IV critical care and two ambulatory Holter cohorts. All metrics are reported with 95% confidence intervals from a cluster bootstrap at the patient, recording or subject levels. ROC–AUC exceeded 0.95 in every cohort, from 0.960 (95% CI 0.956–0.963) on CODE-15 to 0.999 (0.998–0.999) on SPH, including 0.966 (0.965–0.967) on MIMIC-IV with 75.3% sensitivity and 97.7% specificity, 0.963 (0.929–0.987) on CPSC 2021 and 0.995 (0.988–0.999) on MIT-BIH. Performance was stable under progressive lead masking without retraining, and median inference took 110 ms per segment on a server-class CPU without a GPU. A compact network trained on one curated source can therefore generalize across hospitals, countries and recording hardware. This study is retrospective; prospective validation is required before clinical use. Full article

Atrial fibrillation (AF) is the most commonly encountered arrhythmia, with a rapidly growing prevalence and significant cost to the global healthcare system. Left untreated, AF progresses over time from paroxysmal AF to persistent AF (perAF) and long-standing persistent AF (LS-perAF). AF is associated with significant mortality and morbidity by increasing the risk of developing cardiomyopathy, heart failure, dementia, stroke and systemic embolization. Endocardial catheter ablation (CA) targeting pulmonary vein isolation (PVI) alone is the most commonly employed treatment strategy for patients undergoing invasive treatment for all forms of AF. Despite technological improvements such as pulsed field ablation (PFA), procedural success rates in preventing AF recurrences in patients with perAF and LS-perAF remain suboptimal. A lack of lesion transmurality gives rise to epicardial–endocardial dissociation, which may contribute to AF recurrences. Hybrid ablation (HA) combines epicardial surgical ablation with endocardial CA. HA leads to greater freedom from AF in advanced AF compared to CA, and while existing data support the safety of HA, HA inherently is more invasive, requires a multidisciplinary approach, and has a 5–7.8% risk of major adverse events. HA is reasonable in patients with symptomatic, drug-refractory perAF or LS-perAF. Future directions include evaluating the role of novel operative technologies in HA. Full article

Background and Clinical Significance: Multivessel coronary artery spasm (CAS) is an uncommon, high-risk form of vasospastic angina that can produce transient ST-segment elevation mimicking acute myocardial infarction. Evidence to guide management when calcium channel blockers and nitrates fail is scarce, and renal sympathetic denervation (RSD) has been reported in very few patients; Case Presentation: A 53-year-old man with hypertension, type 2 diabetes, and dyslipidemia presented with nocturnal chest pain and inferior ST-segment elevation. Coronary angiography showed severe spontaneous spasm of the right coronary and left anterior descending arteries that resolved completely with intracoronary nitrate; the coronary arteries were otherwise angiographically normal. High-sensitivity cardiac troponin I remained below 10 ng/L (reference 0–34 ng/L), and echocardiography was normal, fulfilling the criteria for definite vasospastic angina without myocardial infarction. The same two-vessel spasm was documented at a second angiogram three months later. Despite maximally tolerated dual calcium channel blockade, nitrates, and statin therapy, he required more than ten further admissions. A self-terminating accelerated idioventricular rhythm lasting about two minutes was recorded. No syncope or malignant arrhythmia occurred, and an electrophysiology review found no current indication for an implantable cardioverter–defibrillator. Radiofrequency RSD was performed off-label for refractory symptoms without complications, but at six months, his symptoms and admissions were unchanged; Conclusions: Our case highlights the diagnostic and therapeutic difficulties in refractory CAS. Accelerated idioventricular rhythm after relief of spasm is a reperfusion rhythm and does not by itself indicate device therapy. In this patient, RSD did not control refractory multivessel CAS, a negative observation that adds to the very limited evidence on autonomic modulation in this setting. Full article

The obese patient with arrhythmia represents a major challenge in cardiology. In these patients, multiple mechanisms converge to create a pro-arrhythmic milieu that remains poorly understood and only partially controllable. The anatomical and functional remodeling of adipose tissue, local inflammation, metabolic alterations, and the frequent presence of associated comorbidities lead to structural, functional, and electrical cardiac changes, resulting in a pro-arrhythmic substrate. The coexistence of these multiple contributing factors may reduce the efficacy of currently available antiarrhythmic therapies in this specific population. Although these obesity-related alterations are not currently established therapeutic targets, they may represent promising targets for future interventions to improve patients’ outcomes. In this narrative review, we summarize the main scientific evidence regarding the pro-arrhythmic cardiac alterations associated with obesity, focusing separately on structural and electrical remodeling and on the role of epicardial and visceral adipose tissue. We conclude by discussing recent evidence suggesting that several therapeutic strategies may reverse this pro-arrhythmic milieu, with a particular focus on established anti-obesity treatments and emerging experimental therapeutic approaches. Full article

Respiratory syncytial virus (RSV) and human metapneumovirus (hMPV) are major causes of respiratory tract infections across different age groups. Although primarily regarded as respiratory pathogens, both viruses have been associated with cardiac complications, whose clinical spectrum remains incompletely characterized. We systematically reviewed published cases of RSV- and hMPV-associated cardiac involvement and compared their clinical characteristics and outcomes. PubMed, Scopus, and EMBASE were systematically searched for reports describing cardiac complications associated with laboratory-confirmed RSV or hMPV infection. Individual patient data were pooled and analyzed using descriptive and univariate analyses. Multivariable logistic regression was used to identify characteristics associated with hMPV versus RSV diagnosis, while multiple correspondence analysis (MCA) was performed to explore multivariate patterns of clinical presentation. Age-stratified sensitivity analyses were additionally performed. Overall, 102 cases were included, comprising 71 RSV (69.6%) and 31 hMPV (30.4%). hMPV cases were significantly older than RSV cases (41.5 years, interquartile range 3.5–63.0 vs. 1.5 years, interquartile range 0.2–31.0; p < 0.001) and had a higher burden of comorbidities. Myocarditis was the most frequently reported cardiac complication in both groups (87.1% hMPV vs. 74.6% RSV), followed by heart failure and pericarditis. ICU admission was more frequent among hMPV cases (96.8% vs. 77.5%; p = 0.034), whereas overall clinical outcomes did not significantly differ between groups. In exploratory multivariable analyses, dyspnea (aOR 16.280, 95% CI 1.370–193.475) and cough (aOR 6.059, 95% CI 1.062–34.552) were associated with hMPV diagnosis, whereas rhinorrhea (aOR 0.031, 95% CI 0.003–0.286) and lethargy/altered mental status (aOR 0.103, 95% CI 0.015–0.712) were associated with RSV diagnosis. ICU admission was also associated with hMPV diagnosis (aOR 11.033, 95% CI 1.125–108.173). These estimates were characterized by wide confidence intervals and should be interpreted cautiously. MCA showed substantial overlap between RSV and hMPV cases, without clear separation of their overall clinical presentation, while most between-group differences were attenuated in age-stratified analyses. In conclusion, both RSV and hMPV can be associated with a broad spectrum of potentially severe cardiac complications, with myocarditis representing the predominant reported manifestation. Despite some differences in demographic and clinical characteristics, their overall cardiac and clinical phenotypes substantially overlap. These findings support greater awareness of potential cardiac involvement during severe RSV and hMPV infections, while highlighting the need for prospective, systematically investigated cohorts to establish the incidence, mechanisms, and long-term outcomes of these complications. Full article

The CACNA1C gene encodes the α_1C subunit of voltage-gated Ca_V1.2 calcium channels, serving many pivotal functions throughout the body, including in the heart and brain. Clinical and genetic evidence implicates altered expression and/or function of CACNA1C/Ca_V1.2 in both cardiac and neuropsychiatric disease, including hypertension, cardiac arrhythmias, coronary artery disease, schizophrenia, bipolar disorder, depression, and autism. Gain-of-function mutations in CACNA1C cause Timothy syndrome, a potentially lethal multi-organ disorder with severe cardiac and neuropsychiatric defects. Conversely, the complete loss of Cacna1c is lethal in mice. The development of viable mouse and rat models with Cacna1c haploinsufficiency has allowed us to study the consequences of reduced expression and function of Cacna1c/Ca_V1.2 for heart and brain function from the molecular and cellular to the behavioral level. We review recent findings from these rodent models, revealing (i) alterations in behavior and (ii) in neuronal and non-neuronal function, as well as (iii) an impaired ability of the heart and its cardiomyocytes to adapt to (sympathetic) stress. Results lend further support to the notion that CACNA1C/Ca_V1.2 dysfunction represents a common link between cardiac and neuropsychiatric disorders and that appropriately targeting CACNA1C/Ca_V1.2 in selected patients may hold the promise of treating both conditions effectively with a single drug. Full article

Postoperative atrial fibrillation remains one of the most common complications after cardiac surgery. Although it is often transient, it can complicate recovery, prolong hospitalization, and identify patients at higher risk of future atrial fibrillation. In daily practice, however, management remains largely reactive, as most patients are recognized only after the arrhythmia has already occurred. This creates an important opportunity for earlier risk stratification. Cardiac surgery is a particularly attractive setting because the event is common, perioperative monitoring is dense, and preoperative 12-lead electrocardiograms are routinely available. Many of these electrocardiograms are recorded in sinus rhythm and may appear normal on clinical review, yet they may still contain subtle signs of latent atrial vulnerability. In this perspective, we argue that postoperative atrial fibrillation after cardiac surgery is a promising use case for clinically meaningful artificial intelligence in 2026. The most compelling next step is to test whether preoperative electrocardiograms add useful information to clinical and biomarker-based risk assessment before the first postoperative episode occurs. Full article

Continuous electrocardiogram (ECG) monitoring in wearable biomedical devices requires processing architectures that balance computational simplicity with hardware efficiency. This paper presents a compact, silicon-proven System-on-Chip (SoC) integrating a PicoRV32 (RV32I) RISC-V processor core with a dedicated multiplierless 1D convolution accelerator for real-time binary ECG anomaly detection. The accelerator implements a hard-wired three-tap Laplacian kernel ($[-1,2,-1]$) coupled with a programmable threshold comparator. By replacing hardware multipliers with a shift-add-negate tree, the datapath requires $O\left(N\right)$ full-adder equivalents for N-bit samples, compared with $O\left(N^2\right)$ for a multiplier-based 3-tap filter, and executes deterministically in a single clock cycle. The accelerator interfaces with the RISC-V core through a memory-mapped handshake bus. Fabricated in a 180-nm CMOS process, the SoC occupies an active core area of 0.936 mm² (9373 standard-cell instances at 75.2% density) and was validated on a custom PCB using a UART host interface streaming MIT-BIH Arrhythmia Database records. On five records (10,393 beats) with per-patient threshold calibration, the chip achieves 95.88% Normal/Abnormal accuracy. At 1.8 V and 100 MHz the measured active power is 25.2 mW, and the measured sleep-mode leakage is 44 nW (44 nA at 1.0 V). These results provide a compact, area-efficient ASIC platform for wearable cardiac monitoring, whose power consumption can be further reduced by operating at lower clock frequencies. Full article

Background: Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia. While pulmonary vein isolation (PVI) remains the cornerstone of AF ablation, the optimal method for confirming complete acute isolation remains uncertain. This study evaluated the diagnostic value of pulmonary vein (PV) pacing compared with repeat three-dimensional (3D) electroanatomical mapping following wide antral circumferential ablation (WACA). Methods: In this prospective observational study, 58 patients with paroxysmal or persistent AF undergoing bilateral WACA at the University Heart Center Ulm between November 2023 and April 2025 were included. Following successful PVI, pacing was performed from each PV and the corresponding carina region using a maximal stimulation output of 20 mA. Subsequently, comprehensive 3D re-mapping was performed to reassess electrical conduction. Results obtained from pacing maneuvers were compared with repeat mapping findings. Results: The study population had a median age of 73 (62.7–78.2) years and a median body mass index of 26.8 (24.0–29.9) kg/m². Median left atrial diameter was 4.8 (4.3–5.5) cm, and moderate to advanced atrial fibrosis was present in approximately one-third of patients. For the left-sided PVs, pacing assessment alone was associated with a significantly higher proportion of false-negative results compared with 3D re-mapping (left upper PV: p = 0.039; left inferior PV: p = 0.012). In contrast, no significant differences were observed for the right PVs. Evaluation of the carina regions showed a similar pattern, with a significant discrepancy on the left side (p = 0.002) but not on the right side (p = 0.453). Conclusions: PV pacing alone may not reliably identify residual conduction within the left PVs and left carina after WACA. Additional 3D re-mapping appears valuable in these regions to detect persistent conduction gaps that could otherwise remain unnoticed. For right-sided PVs, pacing-based assessment may provide sufficient confirmation of acute isolation in many cases. These findings support a complementary use of both techniques to improve procedural verification of PVI. Larger prospective studies are warranted to confirm the observed results and determine their clinical implications. Full article

Mitral valve prolapse (MVP) and mitral annular disjunction (MAD) are common comorbidities that can lead to serious cardiac arrhythmias and sudden cardiac death (SCD). Arrhythmic MVP is characterized by the presence of MVP with frequent (over 5% ventricular extra beats) and/or complex ventricular arrhythmias, such as ventricular tachycardia (VT), non-sustained VT, or ventricular fibrillation in the absence of other causes of arrhythmia, e.g., post-infarction scar, recent ischemia, channelopathy, or cardiomyopathy. The mechanisms of the development of serious cardiac arrhythmias in patients with MVP and MAD are not fully understood. Arrhythmic MVP may be an indication for cardioverter defibrillator implantation. Considering the increased risk of SCD in this group of patients, the pathophysiology of this valvular dysfunction and characteristic deviations in diagnostic tests that indicate a higher risk of SCD are presented. The issue of tailored risk stratification in individual patients is crucial. Full article

Background/Objectives: New-onset atrial fibrillation is a common complication of acute myocardial infarction and is associated with increased mortality, heart failure, and recurrent cardiovascular events. Prediction models for the occurrence of atrial fibrillation may facilitate early risk stratification, improve patient monitoring, and support personalized therapeutic decision-making in clinical practice. Methods: A prospective study included 150 patients with acute myocardial infarction admitted within 24 h of symptom onset. Clinical, laboratory, electrocardiographic, and echocardiographic data were collected, and a machine learning model was developed to predict new-onset atrial fibrillation. Model performance was evaluated using ROC-AUC, while SHAP analysis was applied to identify and quantify the contribution of individual predictors. Results: The machine learning model demonstrated excellent predictive performance, achieving an accuracy of 97.0%, ROC-AUC of 0.991, and precision–recall AUC of 0.991 in the independent test set. SHapley Additive Explanations (SHAP) and permutation importance analyses identified the E/e’ ratio, left ventricular mass index, left ventricular ejection fraction, left atrial volume index, oxidative stress markers (malondialdehyde and superoxide dismutase), NT-proBNP, and complete revascularization as the most influential predictors of new-onset atrial fibrillation after acute myocardial infarction. Conclusions: Machine learning combined with SHAP-based explainability showed high potential for predicting new-onset atrial fibrillation after acute myocardial infarction. This approach may improve individualized risk assessment and clinical decision-making, pending validation in larger multicenter cohorts. Full article

Background: Sudden unexpected death in infancy (SUDI) may occasionally be attributable to neoplasms that were clinically unrecognised before the terminal event and diagnosed or confirmed during post-mortem investigation. These occult neoplasms are exceptionally rare and remain poorly characterised. This scoping review identifies published reports of neoplasms not diagnosed or strongly suspected before the terminal event in infants who died suddenly and unexpectedly, and systematically collects data on pathological features, diagnostic modalities, mechanisms of death, and the extent to which the neoplasm contributed to death. Methods: A search of PubMed/MEDLINE and Scopus was conducted without a lower publication-date restriction through 19 July 2026, in accordance with Joanna Briggs Institute guidance and PRISMA-ScR. Publications describing sudden unexpected deaths in infants younger than 12 months with a previously undiagnosed neoplasm were selected and reviewed. Findings were extracted, and deaths were classified according to whether the neoplasm was causal, contributory, or incidental to death. Results: Twenty-five studies comprising 32 infant cases were included in the review. The median age at death was 2.5 months. The most frequent lesions were cardiovascular or thoracic neoplasms (16/32), followed by haematological or lymphoid neoplasms (6/32). Sixteen lesions were benign, ten were malignant, and six were intermediate, uncertain, or tumour-like. Twenty-five neoplasms were evident on macroscopic examination, whereas seven were identified only histologically. Reported mechanisms of death included arrhythmia, mechanical obstruction, respiratory failure, haemodynamic compromise, haemorrhage, leukostasis, and diffuse infiltration. Within the published cases included in this review, the review team classified the neoplasm as causal in 16 cases (16/32, 50.0%), contributory in 13 cases (13/32, 40.6%), and incidental in three cases (3/32, 9.4%). Conclusions: Autopsy examination is critical for identifying previously undiagnosed neoplasms, which are rare but potentially important findings in the investigation of SUDI. Among the selected published cases included in this review, the review team classified the neoplasm as causal in half of cases; this proportion should not be extrapolated to the broader SUDI population. Comprehensive autopsy assessment of SUDI cases, including thorough histological sampling and ancillary testing, is therefore essential for determining the role of a tumour in infant death. Full article

Background: Implantable cardioverter defibrillators (ICDs) are essential for the primary prevention of sudden cardiac death in heart failure (HF); however, appropriate shocks increase mortality and impair quality of life. The electrical risk score (ERS) is an electrocardiographic (ECG)-based composite index with proven prognostic value, but its ability to predict ventricular arrhythmias in HF remains unclear. This study aims to evaluate the predictive value of the ERS for ventricular arrhythmia-related ICD shocks in HF patients undergoing primary prevention ICD implantation. Methods: In this study, 91 patients with HF were followed for 12 months after ICD implantation. The ERS was calculated from baseline ECGs. Patients were grouped based on ERS (<3 vs. ≥3), according to receiver operating characteristic curve analysis. Multivariate logistic regression was used to evaluate predictors of appropriate ICD shocks, and predictive performance was compared using the DeLong test. Results: Thirty-five patients (38.5%) experienced at least one appropriate ICD shock. The median ERS was significantly higher in the shock group compared to the non-shock group (p < 0.001). Patients with ERS ≥ 3 had significantly higher rates of the anti-tachycardia pacing therapy (p < 0.001) and HF-related hospitalization (p = 0.004). ERS was an independent predictor of ICD shocks (p < 0.001), with superior discriminative performance (AUC 0.882) compared to most ECG markers, including frontal QRS T angle, QRS duration, Tp-e interval, and heart rate. Conclusions: The ERS was associated with ventricular arrhythmia-related ICD shocks in HF patients undergoing primary prevention ICD implantation. The ERS may identify patients at increased arrhythmic risk and guides follow-up and ICD management. Full article

Background/aim: Hemodialysis patients face a high burden of cardiovascular diseases, which account for over 40% of mortality in this population. In these patients, approximately two-thirds of cardiovascular deaths are due to arrhythmia. The aim of this study was to determine whether the ultrafiltration rate is associated with morphological and functional parameters of the left heart and arrhythmias. Methods: This work was a cross-sectional observational clinical study, with 75 hemodialysis patients. Patients were divided into two groups based on ultrafiltration rate (UFR): higher-UFR group, ultrafiltration rate ≥ 10 mL/kg/h (n = 37); lower-UFR group, ultrafiltration rate < 10 mL/kg/h (n = 38). All patients were analyzed for myocardial morphological and functional parameters and arrhythmias. Results: Statistically significant higher values were observed for the left atrium diameter (LAD) (47.56 ± 4.82 vs. 44.75 ± 2.33 mm, p = 0.0019), the left atrial volume index (LAVI) (43.28 ± 7.13 vs. 36.43 ± 8.52 mL/m², p = 0.0003), and the left ventricular mass index (LVMI) (138.47 ± 29.32 vs. 116.04 ± 31.64 g/m², p = 0.0021) in the higher-UFR group. UFR was associated with LAD (OR: 3.6000, 95% CI: 1.3780–9.4053, p = 0.0089), LAVI (OR: 4.1067, 95% CI: 1.5478–10.8956, p = 0.0045), and LVMI (OR: 4.7619, 95% CI: 1.6825–13.4774, p = 0.0033). The frequency of ventricular and supraventricular arrhythmias was similar between the analyzed patient groups. Conclusions: Higher UFR was associated with structural changes in the left heart (LAVI, LAD, and LVMI), but not with other echocardiographic parameters or arrhythmias in hemodialysis patients. Full article