Search Results (218)

A 2-year-old Aberdeen Angus cow was presented with lethargy and decreased appetite at the VA-MA College of Veterinary Medicine Large Animal Teaching Hospital. Initial clinical examination revealed cyanosis, tachycardia, polycythemia, and a significant increase in lactate levels. The heifer experienced spontaneous death while hospitalized, prompting a postmortem examination. Gross evaluation demonstrated that the aorta arose entirely from the right ventricle, while the main pulmonary artery maintained its normal position, consistent with a diagnosis of double-outlet right ventricle. Additional cardiac abnormalities were identified, including an atrial septal defect, ventricular septal defect and marked right ventricular hypertrophy. These defects fall under the category of double-outlet right ventricle malformation. While congenital heart defects are a more recognized cause of cardiac failure and mortality in calves, they should remain a consideration in cases of sudden death, even in adult cattle. Full article

Background: Acute SARS-CoV-2 infection may induce cardiac arrhythmias associated with viral myocarditis, which typically disappear in the convalescent phase after healing of the myocardial inflammation. Methods: We report the case of a 37-year-old woman with a childhood history of atrial septal defect repair and stable normofrequent atrial rhythm, who presented two months post-COVID-19 with palpitations and dizziness. Diagnostic evaluation included cardiac magnetic resonance imaging (CMR), 24 h Holter electrocardiogram (ECG) monitoring, and laboratory assessments over a 3-year period. Results: CMR suggested subacute myocarditis, and Holter ECG revealed multiple discernible complex cardiac arrhythmias including atrial bradycardia, intermittent junctional rhythm (JR), atrial fibrillation (AF), and non-sustained ventricular tachycardia. Laboratory results showed a moderate but transient increase in lactate dehydrogenase, persistently mildly elevated N-terminal pro–B-type natriuretic peptide (NT-proBNP), and immunoglobulin A (IgA), with all other cardiac, inflammatory, immunologic, and organ function parameters remaining normal. In spite of chaotic cardiac rhythm with alternating JR, AF, and atrial normofrequent rhythm with frequent blocked supraventricular beats and increasing atrioventricular conduction time, no therapeutic intervention was necessary during follow-up, and a conservative treatment approach was agreed with the patient. Two years post-COVID-19 infection, the patient returned to a normofrequent atrial rhythm with a markedly prolonged PQ time (500 ms) and a different P wave morphology compared to pre-COVID, without other rhythm disturbances. Conclusions: This case demonstrates a rare pattern of post-viral arrhythmias first emerging in the convalescent phase and resolving spontaneously after two years. It underscores the need for long-term rhythm surveillance following COVID-19, even in patients with prior structural heart disease and a stable baseline rhythm. Full article

Background and Clinical Significance: Heart failure with reduced ejection fraction (HFrEF) and atrial fibrillation (AF) frequently coexist, creating a complex clinical interplay that exacerbates morbidity and mortality. AF can directly precipitate or worsen HFrEF through mechanisms such as tachycardia-induced cardiomyopathy, loss of atrial contribution to ventricular filling, and irregular ventricular response. The use of evidence-based therapies improves clinical outcomes in patients with HFrEF. Case Presentation: We present a clinical case of a 58-year-old man with left bundle branch block (LBBB), tachysystolic AF, and the aforementioned induced HFrEF. The patient’s medical treatment was optimized according to recent guidelines. Subsequent to the improvements in HF treatment, the patient’s echocardiographic data showed a higher left ventricle ejection fraction (LVEF); however, it remained below 35%. Moreover, tachysystolia persisted and was not sufficiently controlled with medications. Therefore, an upgrade of the pacemaker to cardiac resynchronization therapy (CRT) following the destruction of the AV node was performed to control tachysystolic AF and worsening of HF. After the treatment adjustments, the patient’s symptoms regressed, and echocardiography showed improved LVEF up to 41%. Conclusions: This case highlights the successful identification and timely application of intensive heart rate control management and heart failure induced by AF treatment. Full article

Background: The influence of the initial ablation modality on pulmonary vein (PV) reconnection and substrate characteristics in redo procedures for recurrent atrial fibrillation (AF) remains unclear. We assessed how different thermal strategies—ablation index (AI)-guided radiofrequency (RF) versus cryoballoon (CB) ablation—affect remapping findings during redo pulmonary vein isolation (PVI). Methods: We included patients undergoing redo ablation between 2015 and 2024 with high-density electroanatomic mapping. Initial PVI modalities were retrospectively classified as low-power, long-duration (LPLD) RF; high-power, short-duration (HPSD) RF; or second-/third-generation CB. Reconnection sites were mapped using multielectrode catheters. Redo PVI was performed using AI-guided RF. Segments showing PV reconnection were reisolated; if all PVs remained isolated and AF persisted, posterior wall isolation was performed. Results: Among 195 patients (LPLD: 63; HPSD: 30; CB: 102), complete PVI at redo was observed in 0% (LPLD), 23.3% (HPSD), and 10.1% (CB) (p < 0.01 for LPLD vs. HPSD). Reconnection patterns varied by technique; LPLD primarily affected the right carina, while HPSD and CB showed reconnections at the LSPV ridge. Organized atrial tachycardia was least frequent after CB (12.7%, p < 0.002). Conclusion: Initial ablation strategy significantly influences PV reconnection and post-PVI arrhythmia patterns, with implications for redo procedure planning. Full article

Fetal tachyarrhythmias, particularly supraventricular tachycardia (SVT) and atrial flutter (AFL), pose significant clinical challenges, especially when complicated by hydrops fetalis. This article provides a comprehensive review of the tachyarrhythmia types, the diagnostic modalities applied, and the therapeutic strategies followed in fetal tachyarrhythmias. Diagnostic techniques such as M-mode echocardiography and fetal magnetocardiography (fMCG) are highlighted for their capacity to provide real-time, high-quality assessments of fetal cardiac rhythms. The review, also, focuses on pharmacologic management via transplacental therapy, discussing the safety and efficacy of the key agents including digoxin, flecainide, and sotalol, under different clinical scenarios, such as hydropic fetus and renal impairment. In addition to transplacental administration, alternative approaches such as direct fetal intramuscular or intravascular injections are examined. These direct methods, while potentially more effective in refractory cases, carry risks that necessitate specialized expertise and careful consideration of maternal and fetal safety. The limitations of current evidence, largely based on small case studies and retrospective analyses, underscore the need for larger, prospective multicenter observational studies and randomized control trials to establish standardized protocols for fetal tachyarrhythmia management. Overall, this review advocates for a personalized, multidisciplinary approach, emphasizing early fetal tachyarrhythmias diagnosis, tailored treatment regimens that balances efficacy with safety, and rigorous monitoring to optimize outcomes for both the fetus and the mother. Full article

Cardiac arrhythmias remain a major source of morbidity and mortality, often stemming from molecular and structural abnormalities that are insufficiently addressed by current pharmacologic and interventional therapies. Gene therapy has emerged as a transformative approach, offering precise and durable interventions that directly target the arrhythmogenic substrate. Across the spectrum of inherited and acquired arrhythmias—including long QT syndrome, Brugada syndrome, catecholaminergic polymorphic ventricular tachycardia, atrial fibrillation, and post-infarction ventricular tachycardia—gene-based strategies such as allele-specific silencing, gene replacement, CRISPR-mediated editing, and suppression-and-replacement constructs are showing growing translational potential. Advances in delivery platforms, including cardiotropic viral vectors, lipid nanoparticle-encapsulated mRNA, and non-viral reprogramming tools, have further enhanced the specificity and safety of these approaches. Additionally, innovative applications such as biological pacemaker development and mutation-agnostic therapies underscore the versatility of genetic modulation. Nonetheless, significant challenges remain, including vector tropism, immune responses, payload limitations, and the translational gap between preclinical models and human electrophysiology. Integration of patient-derived cardiomyocytes, computational simulations, and large-animal studies is expected to accelerate clinical translation. This review provides a comprehensive synthesis of the mechanistic rationale, therapeutic strategies, delivery platforms, and translational frontiers of gene therapy for cardiac arrhythmias. Full article

Background and Objectives: The perioperative use of beta-blockers remains controversial due to conflicting evidence of their risks and benefits. The aim of this study was to evaluate the association between chronic beta-blocker (bb) therapy and perioperative cardiac events in non-cardiac surgeries using 24 h continuous Holter monitoring. Materials and Methods: A prospective observational study was conducted on patients undergoing elective or emergency non-cardiac surgery at a Romanian tertiary care hospital. The patients were divided into two groups: G1 (not receiving Bb) and G2 (on chronic Bb). The incidences of perioperative cardiac events, such as severe bradycardia (<40 b/min), new-onset atrial fibrillation (AF), extrasystolic arrhythmia (Ex), and sustained ventricular tachycardia (sVT) and arterial hypotension, were compared between the two groups using clinical, electrocardiography (ECG), and Holter ECG data. Beta-blocker indications, complications, and outcomes were analyzed using chi-squared tests and logistic regression. Results: A total of 100 consecutive patients (63% men, mean age of 53.7 years) were enrolled in the study. G2 included 30% (n = 30) of patients on chronic beta-blocker therapy. The indications included atrial fibrillation (46.7%, n = 14), arterial hypertension (36.7%, n = 11), extrasystolic arrhythmias (10%, n = 3), and chronic coronary syndrome (6.6%, n = 2). Beta-blocker use was significantly associated with severe bradycardia (n = 6; p < 0.001) in G2, whereas one patient in G1 had bradycardia, and 15 and 1 patients had hypotension (p < 0.001) in G1 and G2, respectively. The bradycardia and arterial hypotension cases were promptly treated and did not influence the patients’ prognoses. The 14 patients with AF in G2 had a 15-fold higher odds of requiring beta-blockers (p < 0.001, odds ratio (OR) = 15.145). No significant associations were found between beta-blocker use and the surgery duration (p = 0.155) or sustained ventricular tachycardia (p = 0.857). Ten patients developed paroxysmal postoperative atrial fibrillation (AF), which was related to longer surgery durations (165 (150–180) vs. 120 (90–150) minutes; p = 0.002) and postoperative anemia [hemoglobin (Hg): 10.4 (9.37–12.6) vs. 12.1 (11–13.2) g/dL; p = 0.041]. Conclusions: Patients under chronic beta-blocker therapy undergoing non-cardiac surgery have a higher risk of perioperative bradycardia and hypotension. Continuous Holter monitoring proved effective in detecting transient arrhythmic events, emphasizing the need for careful perioperative surveillance of these patients, especially the elderly, in order to prevent cardiovascular complications These findings emphasize the necessity of tailored perioperative beta-blocker strategies and support further large-scale investigations to optimize risk stratification and management protocols. Full article

Background/Objectives: Catheter ablation has become the standard of care for patients with symptomatic and drug-refractory atrial fibrillation (AF). Both Class IC and Class III antiarrhythmic drugs (AADs) are effective in preventing early recurrences of AF, but not late recurrences, compared with the usual care. We aimed to compare the effects of two months of Class IC versus Class III AADs following AF catheter ablation on clinical outcomes, including arrhythmia recurrence and safety endpoints. Methods: All patients undergoing AF catheter ablation between January 2015 and November 2024 were screened, and cases meeting the inclusion criteria were included. Primary outcome was defined as atrial tachycardia recurrence-free survival. Results: A total of 98 patients (mean age 54.2 ± 14.0 years; 55.1% male) were enrolled, with 66.3% presenting with paroxysmal atrial fibrillation (AF). The mean left atrial diameter was 38.7 ± 5.1 mm, and 78.6% underwent cryoballoon ablation. Class IC AADs were administered to 62 cases, while the remaining 36 patients received amiodarone following catheter ablation. The rate of atrial tachycardia (ATa) recurrence was comparable between the patients treated with Class IC and Class III AADs (9.7% vs. 19.4%; p = 0.169). Predictors of ATa recurrence were identified as history of direct current cardioversion—DCCV (HR: 5.86; 95%CI: 1.44–23.82)—and LA diameter (HR: 1.17; 95%CI: 1.04–1.31). The most frequent AAD-related adverse event was symptomatic bradycardia (6.1%), which resolved in all cases following dose reduction. Conclusions: Class IC and Class III antiarrhythmics show comparable efficacy in terms of preventing ATa recurrence following AF catheter ablation. AAD-related adverse event rates are negligible for short-term use. Full article

Background/Objectives: Left atrial function can be a tool for risk stratification for hypertrophic cardiomyopathy (HCM). Over the past decade, there has been growing interest in the application of strain analysis for earlier and more accurate prediction of cardiovascular disease prognosis. This study aimed to investigate the performance of left atrial strain analysis compared to conventional left atrial measures in predicting clinical outcomes in Asian patients with HCM. Methods and Results: This was a retrospective study involving 291 patients diagnosed with HCM between 2010 and 2017. Left atrial volumes were assessed using the method of discs in orthogonal plans at both end diastole and end systole. Left atrial (LA) strain was obtained using a post-hoc analysis with TOMTEC software. We tested the various left atrial parameters against outcomes of (1) heart failure hospitalization and (2) event-free survival from a composite of adverse events, including all-cause mortality, ventricular tachycardia (VT)/ventricular fibrillation (VF) events, appropriate device therapy if an implantable cardioverter defibrillator (ICD) was implanted, stroke, and heart failure hospitalization. The patients had a mean age of 59.0 ± 16.7 years with a male preponderance (71.2%). The cumulative event-free survival over a follow-up of 3.9 ± 2.7 years was 55.2% for patients with an abnormal LA strain versus 82.4% for patients without one (p < 0.001). Multivariable Cox regression analyses were performed separately for each LA parameter, adjusting for age, sex, LV mass index, LV ejection fraction (EF), E/e’, the presence of LV outflow tract (LVOT) obstruction at rest, and atrial fibrillation. An analysis showed that all parameters except for LAEF demonstrated an independent association with heart failure hospitalization. Left atrial strain outperformed the rest of the parameters by demonstrating an association with a composite of adverse events. Conclusions: In Asian patients with HCM, measures of left atrial strain were independently associated with heart failure hospitalization and a composite of adverse outcomes. Left atrial strain may be used as a tool to predict adverse outcomes in patients with HCM. Full article

The anatomical arrangement of the atrioventricular node has been likened to a riddle wrapped up in an enigma. There are several reasons for this alleged mystery, not least the marked variability in structure between different species. Lack of detailed knowledge of the location of the node relative to the atrial and ventricular septal structures has also contributed to previous misunderstandings. Recent studies comparing the findings of gross dissection with virtual dissection of living datasets, combined with access to a large number of serially sectioned human and animal hearts, have served to provide the evidence to solve the riddle. We summarise these findings in this review. We explain how the node is located within the atrial walls of the inferior pyramidal space. It becomes the non-branching component of the atrioventricular conduction axis as the axis extends through the plane of atrioventricular insulation to enter the infero-septal recess of the left ventricular outflow tract. The node itself is formed by contributions from the tricuspid and mitral vestibules, with extensive additional inputs from the base of the atrial septum. We show how knowledge of development enhances the appreciation of the arrangements and offers an explanation as to why, on occasion, there can be persisting nodoventricular connections. We discuss the findings relative to the circuits producing atrioventricular re-entry tachycardia. We conclude by emphasising the significance of the variation of the anatomical arrangements within different mammalian species. Full article

Hereditary transthyretin amyloidosis (ATTRv) is an autosomal dominant disorder caused by pathogenic variants in the TTR gene. The destabilized mutant form of the transport protein transthyretin (TTR) leads to the extracellular deposition of amyloid fibrils. Materials and Methods: A 65-year-old female patient with suspected clinical diagnosis of ATTR was referred for genetic testing for pathogenic variants in the TTR gene after physical, neurological and cardiac testing. Results: The patient had had cardiac dysfunction, atrial fibrillation and supraventricular tachycardia for around 10 years before the suspected and confirmed cardiac amyloidosis. The molecular genetic testing showed a heterozygous pathogenic variant in exon 3 of the TTR gene NM_000371.4(TTR): c.258A>C, p.(Glu86Asp). This variant in the TTR gene is classified as pathogenic in accordance with ACMG/AMP for the interpretation of variants. Conclusions: The presented case of a very rare pathogenic variant in the TTR gene displays the valuable role of genetic testing on the way to clarifying a diagnosis. Full article

Enterovirus (EV) infections in neonates can be transmitted vertically or horizontally, with symptoms ranging from mild to severe, including myocarditis, meningoencephalitis, and hepatitis. Neonates with EV-induced myocarditis may present severe cardiovascular disease with sudden onset of arrhythmia. Neonatal arrhythmias, particularly in low birth weight or critically ill infants, can impair cardiac function and worsen outcomes. EV targets cardiomyocyte receptors, inducing apoptosis pathways and triggering cardiac conduction disturbances. We present an extremely low-birth-weight preterm infant (GW 27 + 6) who developed EV-induced myocarditis, complicated with a sudden onset of supraventricular tachycardia (SVT), pericardial effusion and bi-atrial enlargement. Despite multi-agent regimen, including propranolol, flecainide, and amiodarone, the infant showed persistent junctional rhythm until seven months of age, later transitioning to atrial rhythm with stable cardiac function. A review of previously published rhythm disturbances due to EV-induced myocarditis is presented. Newborns with EV-induced arrhythmia may require a multi-modal treatment such as a multi-agent medical regimen or, in severe non-responsive cases, an electrophysiological approach. EV infections may cause long-term cardiovascular comorbidities (such as left ventricular dysfunction or mitral valve regurgitation), necessitating continuous monitoring through echocardiography and ECG. Collaboration between neonatologists and pediatric cardiologists is crucial for effective treatment and follow-up. Full article

This study aims to analyze electrocardiogram (ECG) data for the classification of five cardiac rhythms: sinus bradycardia (SB), sinus rhythm (SR), atrial fibrillation (AFIB), supraventricular tachycardia (SVT), and sinus tachycardia (ST). While SR is considered normal, the other four represent types of cardiac arrhythmias. A range of methods is utilized, including the supervised learning technique K-Nearest Neighbors (KNNs), combined with dimensionality reduction approaches such as Principal Component Analysis (PCA) and Uniform Manifold Approximation and Projection (UMAP), a modern method based in Riemannian topology. Additionally, logistic regression was applied using both maximum likelihood and Bayesian methods, with two distinct prior distributions: an informative normal prior and a non-informative Jeffreys prior. Performance was assessed using evaluation metrics such as positive predictive value (PPV), negative predictive value (NPV), specificity, sensitivity, accuracy, and F1-score. Ultimately, the UMAP-KNN method demonstrated the best overall performance. Full article

Background: Patients with arrhythmias, particularly paroxysmal supraventricular tachycardia (PSVT), face an increased risk of cardiac complications. Currently, non-parenteral medications for rapid PSVT cessation are lacking. Etripamil, a novel intranasal, short-acting calcium channel blocker, offers a rapid onset and the potential for unsupervised PSVT management. However, data on its use in arrhythmia management remain limited. Aims: We aimed to assess the efficacy and safety of 70 mg of etripamil compared with placebo in the treatment of PSVT. Methods: We systematically searched PubMed, Embase, Web of Science, Scopus, and the Cochrane Library for randomized controlled trials (RCTs) from inception to April 2025. We calculated pooled risk ratios (RRs) with 95% confidence intervals (CIs) using random or common effects models, depending on the heterogeneity. Results: Four RCTs including 540 patients were analyzed. Etripamil demonstrated higher conversion rates to the sinus rhythm at 15 min (RR 1.84 [95% CI: 1.32–2.48]), 30 min (RR 1.80 [95% CI: 1.38–2.35]), and 60 min (RR 1.24 [95% CI: 1.04–1.48]). PSVT recurrence rates were similar between groups (RR 0.52 [95% CI: 0.20–1.34]). Adverse events (AEs) and severe AEs were comparable between etripamil and the placebo. Etripamil was associated with higher rates of nasal discomfort, nasal congestion, rhinorrhea, and epistaxis but not with increased bradyarrhythmia, atrial fibrillation, or non-sustained ventricular tachycardia. Conclusions: Etripamil appears to be a promising treatment for cardiac arrhythmias. Larger long-term RCTs are needed to confirm its safety and efficacy in clinical practice. Full article

Echocardiographic values can vary between dog breeds, making breed-specific reference intervals (RIs) preferable. Two-dimensional speckle tracking echocardiography (2-D STE) is an advanced imaging technique that enables the measurement of myocardial deformation parameters, contributing to the assessment of systolic function. The objective was to determine breed-specific RIs for 2-D, M-mode, and Doppler-derived echocardiographic parameters for Dutch Sheepdogs, and to obtain 2-D STE-derived strain and strain rate values in this breed. Apparently healthy, purebred Dutch Sheepdogs (1–7 years) were recruited. Each dog underwent a physical examination and transthoracic echocardiography. Conventional 2-D, M-mode, and Doppler measurements were obtained; strain analysis was performed with 2-D STE software. RIs were established for conventional echocardiographic parameters; clinically relevant parameters were compared with commonly used RIs. The effects of gender, age, body weight (BW) and heart rate were tested. Sixty dogs were included. Panting and/or tachycardia were observed in 24 dogs, which affected the quality of the analysis to varying degrees (e.g., out-of-sector movement, lung artefacts). The selected parameters for left ventricular (LV) and atrial dimension showed good agreement with published RIs. BW was an independent variable influencing LV dimensions. This study provides RIs for conventional echocardiographic measurements and reports 2-D STE-derived strain and strain rate values obtained in Dutch Sheepdogs. The selected parameters of LV and left atrial dimension showed good agreement with commonly used RIs. Anxious behavior could represent a breed peculiarity to take into account when performing echocardiography, as it can affect image quality. Full article