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Background Wide QRS complex (QRS) tachycardia in patients with atrial fibrillation (AF) or atrial flutter treated with antiarrhythmic drugs can occur for a variety of reasons and needs careful evaluation for appropriate management of the patient. Case summary We report a case of wide QRS complex tachycardia in a patient with AF treated with Flecainide who received multiple external cardioversion attempts for a presumed diagnosis of ventricular tachycardia. Intravenous Diltiazem and an oral beta-blocker led to the resolution of wide QRS complex tachycardia. Discussion Wide QRS tachycardia due to pro-arrhythmic effect or rate-dependency phenomenon of antiarrhythmic agents should be included in the differentials. In this brief report, we discuss the differential diagnosis and outline a practical approach for acute and long-term management of these patients. [ABSTRACT FROM AUTHOR]

Introduction: Pharmaceutical residues are widely detected in aquatic environment and can be taken up by nontarget species such as fish. The cytochromes P450 (CYP) represent an important detoxification mechanism in fish, like in humans. In the present study, we assessed the correlation of the substrate selectivities of rainbow trout CYP1A and CYP3A homologues with those of human, through determination of the half-maximal inhibitory concentrations (IC50) of a total sixteen human pharmaceuticals toward CYP1A-like ethoxyresorufin O-deethylase (EROD) and CYP3A-like 7-benzyloxy-4-trifluoromethylcoumarin O-debenzylase (BFCOD) in rainbow trout (Oncorhynchus mykiss) liver S9 fractions (RT-S9). Methods: The inhibitory impacts (IC50) of atomoxetine, atorvastatin, azelastine, bimatoprost, clomethiazole, clozapine, desloratadine, disulfiram, esomeprazole, felbinac, flecainide, orphenadrine, prazosin, quetiapine, sulpiride, and zolmitriptan toward the EROD and BFCOD activities in RT-S9 were determined using the IC50 shift assay, capable of identifying time-dependent inhibitors (TDI). Additionally, the nonspecific binding of the test pharmaceuticals to RT-S9 was assessed using equilibrium dialysis. Results: Most test pharmaceuticals were moderate to weak inhibitors of both EROD and BFCOD activity in RT-S9, even if most are noninhibitors of human CYP1A or CYP3A. Only bimatoprost, clomethiazole, felbinac, sulpiride, and zolmitriptan did not inhibit either activity in RT-S9. EROD inhibition was generally stronger than that of BFCOD and some substances (atomoxetine, flecainide, and prazosin) inhibited selectively only EROD activity. The strongest EROD inhibition was detected with azelastine and esomeprazole (unbound IC50 of 3.8 ± 0.5 µM and 3.0 ± 0.8 µM, respectively). None of the test substances were TDIs of BFCOD, but esomeprazole was a TDI of EROD. Apart from clomethiazole and disulfiram, the nonspecific binding of the test pharmaceuticals to the RT-S9 was extensive (unbound fractions <0.5) and correlated well (R2 = 0.7135) with their water-octanol distribution coefficients. Discussion: The results indicate that the P450 interactions in RT-S9 cannot be explicitly predicted based on human data, but the in vitro data reported herein can shed light on the substrate selectivity of rainbow trout CYP1A1 and CYP3A27 in comparison to their human homologues. The IC50 concentrations are however many orders of magnitude higher than average environmental concentrations of pharmaceuticals. The time-dependent EROD inhibition by esomeprazole could warrant further research to evaluate its possible interlinkages with hepatotoxic impacts on fish. [ABSTRACT FROM AUTHOR]

BACKGROUND: In severely affected patients with catecholaminergic polymorphic ventricular tachycardia, beta-blockers are often insufficiently protective. The purpose of this study was to evaluate whether flecainide is associated with a lower incidence of arrhythmic events (AEs) when added to beta-blockers in a large cohort of patients with catecholaminergic polymorphic ventricular tachycardia. METHODS: From 2 international registries, this multicenter case cross-over study included patients with a clinical or genetic diagnosis of catecholaminergic polymorphic ventricular tachycardia in whom flecainide was added to beta-blocker therapy. The study period was defined as the period in which background therapy (ie, beta-blocker type [beta1-selective or nonselective]), left cardiac sympathetic denervation, and implantable cardioverter defibrillator treatment status, remained unchanged within individual patients and was divided into pre-flecainide and on-flecainide periods. The primary end point was AEs, defined as sudden cardiac death, sudden cardiac arrest, appropriate implantable cardioverter defibrillator shock, and arrhythmic syncope. The association of flecainide with AE rates was assessed using a generalized linear mixed model assuming negative binomial distribution and random effects for patients. RESULTS: A total of 247 patients (123 [50%] females; median age at start of flecainide, 18 years [interquartile range, 14-29]; median flecainide dose, 2.2 mg/kg per day [interquartile range, 1.7-3.1]) were included. At baseline, all patients used a beta-blocker, 70 (28%) had an implantable cardioverter defibrillator, and 21 (9%) had a left cardiac sympathetic denervation. During a median pre-flecainide follow-up of 2.1 years (interquartile range, 0.4-7.2), 41 patients (17%) experienced 58 AEs (annual event rate, 5.6%). During a median on-flecainide follow-up of 2.9 years (interquartile range, 1.0-6.0), 23 patients (9%) experienced 38 AEs (annual event rate, 4.0%). There were significantly fewer AEs after initiation of flecainide (incidence rate ratio, 0.55 [95% CI, 0.38-0.83]; P=0.007). Among patients who were symptomatic before diagnosis or during the pre-flecainide period (n=167), flecainide was associated with significantly fewer AEs (incidence rate ratio, 0.49 [95% CI, 0.31-0.77]; P=0.002). Among patients with ≥1 AE on beta-blocker therapy (n=41), adding flecainide was also associated with significantly fewer AEs (incidence rate ratio, 0.25 [95% CI, 0.14-0.45]; P

Background: Intravenous (IV) flecainide is recommended for the pharmacological cardioversion of recent-onset atrial fibrillation (AF). The aim of this study was to study the efficacy and safety of IV flecainide, co-administered with oral b-blockers, for the cardioversion of paroxysmal AF. Methods: Single-center registry, initiated in the “Skylitseion” General Hospital of Chios in January 2020. The main inclusion criterion was IV flecainide administration plus oral b-blocker for recent-onset AF (≤48 h). The primary outcome was conversion to sinus rhythm at 2 h. Results: A total of 121 (73 males and 48 females, with mean age 61.4 years) consecutive, unselected patients who complied with the study protocol were included. A successful conversion to sinus rhythm at 2 h was achieved in 99 patients (success rate: 81.8%). The median conversion time was 11.7 min (varied from 3 to 23 min). Duration of hospitalization was significantly shorter in patients who were successfully cardioverted with IV flecainide (10.9 vs. 30.7 h, p < 0.001). No serious adverse events were recorded. Conclusion: This is one of the largest registries worldwide, evaluating the effectiveness and safety of IV flecainide co-administered with a b-blocker in the acute management of recent-onset AF. The successful conversion rate at 2 h is very high and quick with no serious adverse events.

Background: Flecainide is an anti-arrhythmic medication with a narrow therapeutic index and a high mortality rate, when overdosed. Few cases of flecainide toxicity in neonates and children due to medication error have been reported in the literature. A case of an accidental flecainide overdose in a neonate in Oman was presented. Case Presentation: A 19-day-old newborn girl developed persistent supra ventricular tachycardia (SVT) after receiving nebulized albuterol for acute bronchitis. After unsuccessful treatment with adenosine, she was given flecainide 5.6 mg orally every 24 hours for resolution of the SVT. On day four of admission, the child inadvertently received 100 mg of flecainide orally due to a dose calculation error. The child developed wide complex tachyarrhythmia followed by pulseless ventricular tachycardia (VT) requiring cardiopulmonary resuscitation. Sodium bicarbonate IV bolus followed by an infusion was administered. The patient developed two additional episodes of pulseless VT that coincided temporally with two interruptions of the sodium bicarbonate infusion, and required high dose of inotropic support. The patient developed convulsions but her brain ultrasound was normal. Her condition stabilized on day three after the toxicity occurred. Repeated echo showed a normal EF. The patient was discharged on propranolol and levetiracetam and was doing well on outpatient follow up. Conclusion: Flecainide is a potentially lethal medication in overdose due to its sodium channel blocking properties. Sodium bicarbonate remains an essential component of treatment. [SJEMed 2024; 5(1.000): 049-054]

Background: Intravenous (IV) flecainide is recommended for the pharmacological cardioversion of recent-onset atrial fibrillation (AF). The aim of this study was to study the efficacy and safety of IV flecainide, co-administered with oral b-blockers, for the cardioversion of paroxysmal AF. Methods: Single-center registry, initiated in the "Skylitseion" General Hospital of Chios in January 2020. The main inclusion criterion was IV flecainide administration plus oral b-blocker for recent-onset AF (≤48 h). The primary outcome was conversion to sinus rhythm at 2 h. Results: A total of 121 (73 males and 48 females, with mean age 61.4 years) consecutive, unselected patients who complied with the study protocol were included. A successful conversion to sinus rhythm at 2 h was achieved in 99 patients (success rate: 81.8%). The median conversion time was 11.7 min (varied from 3 to 23 min). Duration of hospitalization was significantly shorter in patients who were successfully cardioverted with IV flecainide (10.9 vs. 30.7 h, p < 0.001). No serious adverse events were recorded. Conclusion: This is one of the largest registries worldwide, evaluating the effectiveness and safety of IV flecainide co-administered with a b-blocker in the acute management of recent-onset AF. The successful conversion rate at 2 h is very high and quick with no serious adverse events. [ABSTRACT FROM AUTHOR]

Aims A mechanistic link between depression and risk of arrhythmias could be attributed to altered catecholamine metabolism in the heart. Monoamine oxidase-A (MAO-A), a key enzyme involved in catecholamine metabolism and longstanding antidepressant target, is highly expressed in the myocardium. The present study aimed to elucidate the functional significance and underlying mechanisms of cardiac MAO-A in arrhythmogenesis. Methods and results Analysis of the TriNetX database revealed that depressed patients treated with MAO inhibitors had a lower risk of arrhythmias compared with those treated with selective serotonin reuptake inhibitors. This effect was phenocopied in mice with cardiomyocyte-specific MAO-A deficiency (cMAO-Adef), which showed a significant reduction in both incidence and duration of catecholamine stress-induced ventricular tachycardia compared with wild-type mice. Additionally, cMAO-Adef cardiomyocytes exhibited altered Ca2+ handling under catecholamine stimulation, with increased diastolic Ca2+ reuptake, reduced diastolic Ca2+ leak, and diminished systolic Ca2+ release. Mechanistically, cMAO-Adef hearts had reduced catecholamine levels under sympathetic stress, along with reduced levels of reactive oxygen species and protein carbonylation, leading to decreased oxidation of Type II PKA and CaMKII. These changes potentiated phospholamban (PLB) phosphorylation, thereby enhancing diastolic Ca2+ reuptake, while reducing ryanodine receptor 2 (RyR2) phosphorylation to decrease diastolic Ca2+ leak. Consequently, cMAO-Adef hearts exhibited lower diastolic Ca2+ levels and fewer arrhythmogenic Ca2+ waves during sympathetic overstimulation. Conclusion Cardiac MAO-A inhibition exerts an anti-arrhythmic effect by enhancing diastolic Ca2+ handling under catecholamine stress. [ABSTRACT FROM AUTHOR]

Background: Atrial fibrillation (AF) is associated with an increased risk of hospital admission, but few data on reasons for hospitalization and on the role of anti-arrhythmic drugs are available. Objectives: The purpose of this study was to investigate the incidence rate and factors associated with all-cause, cardiovascular, and AF-related hospitalizations. Methods: Prospective ongoing ATHERO-AF (Atherosclerosis in Atrial Fibrillation) cohort study enrolling AF patients on oral anticoagulants. Primary end points were all-cause, cardiovascular, and AF-related hospitalization, the latter defined as AF recurrences for paroxysmal AF and high-rate symptomatic AF episodes for persistent/permanent AF patients. Results: 2,782 patients were included (43.5% female; mean age was 74.6 ± 9.1 years). During a mean follow-up of 31 ± 26.8 months, 1,205 (12.1%/year) all-cause, 533 cardiac (5.7%/year), and 180 (2.0%/year) AF-related hospitalizations occurred. Predictors of AF-related hospitalizations were the use of flecainide/propafenone in both paroxysmal and persistent/permanent AF patients (HR: 1.861; 95% CI: 1.116 to 3.101 and 1.947; 95% CI: 1.069 to 3.548, respectively). Amiodarone (HR: 3.012; 95% CI: 1.835-4.943), verapamil/diltiazem (HR: 2.067; 95% CI: 1.117-3.825), and cancer (HR: 1.802; 95% CI: 1.057-3.070) but not beta-blockers and digoxin were associated with an increased risk of AF-related hospitalizations in persistent/permanent AF patients. Conclusions: Elderly AF patients frequently undergo hospitalizations for both cardiovascular and noncardiovascular causes. The use of anti-arrhythmic drugs was associated with an increased risk of AF-related hospitalization suggesting a scarce effect of these drugs in preventing AF episodes. Therefore, their use should be carefully considered and reserved for symptomatic patients with frequent AF recurrences.

Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a severe hereditary arrhythmia syndrome predominantly affecting children and young adults. It manifests through bidirectional or polymorphic ventricular arrhythmia, often culminating in syncope triggered by physical exertion or emotional stress which can lead to sudden cardiac death. Most cases stem from mutations in the gene responsible for encoding the cardiac ryanodine receptor (RyR2), or in the Calsequestrin 2 gene (CASQ2), disrupting the handling of calcium ions within the cardiac myocyte sarcoplasmic reticulum. Diagnosing CPVT typically involves unmasking the arrhythmia through exercise stress testing. This diagnosis emerges in the absence of structural heart disease by cardiac imaging and with a normal baseline electrocardiogram. Traditional first-line treatment primarily involves β-blocker therapy, significantly reducing CPVT-associated mortality. Adjunctive therapies such as moderate exercise training, flecainide, left cardiac sympathetic denervation and implantable cardioverter-defibrillators have been utilized with reasonable success. However, the spectrum of options for managing CPVT has expanded over time, demonstrating decreased rates of arrhythmic events. Furthermore, ongoing research into potential new therapies including gene therapies has the potential to further enhance treatment paradigms. This review aims to succinctly encapsulate the contemporary understanding of the clinical characteristics, diagnostic approach, established therapeutic interventions and the promising future directions in managing CPVT. [ABSTRACT FROM AUTHOR]

Background: Supraventricular tachycardia (SVT) is one of the most common non-benign arrhythmias in neonates, potentially leading to cardiac decompensation. This study investigated the early risk factors of acute heart failure (AHF) secondary to SVT in neonates, and explored their value in guiding the selection of effective anti-arrhythmic treatment. Methods: A total of 43 newborns diagnosed with and treated for SVT between January 2017 and December 2022 were analyzed. According to the presence of AHF after restoring sinus rhythm in newborns with SVT, they were divided into SVT with AHF group and SVT without AHF group. Clinical data and anti-arrhythmic therapies were analyzed. Risk factors of AHF secondary to SVT in neonates were determined using logistic regression. The cut-off value for predictors of AHF secondary to SVT and demanding of a second-line anti-arrhythmic treatment was determined through receiver operating characteristic (ROC) analysis. Results: Time to initial control of tachycardia > 24 h, hyperkalemia, anemia, and plasma B-type natriuretic peptide (BNP) were identified as risk factors of AHF secondary to SVT in neonates. BNP exhibited AUC of 0.80 in predicting AHF, and BNP > 2460.5pg/ml (OR 2.28, 95% CI 1.27 ~ 45.39, P = 0.03) was an independent predictor, yielding sensitivity of 70.6% and specificity of 84.6%. Neonates with BNP > 2460.5pg/ml (37.5% versus 7.4%, P = 0.04) had a higher demand for a second line anti-arrhythmic treatment to terminate SVT, with sensitivity and specificity for BNP in predicting at 75.0%, 71.4%, respectively. Conclusions: BNP could be used to predict an incident of AHF secondary to SVT and a demand of second-line anti-arrhythmic treatment to promptly terminate SVT and prevent decompensation in neonates. [ABSTRACT FROM AUTHOR]

Background: Tumour necrosis factor superfamily protein 14 (TNFSF14), also called LIGHT, is an important regulator of immunological and fibrosis diseases. However, its specific involvement in cardiac fibrosis and atrial fibrillation (AF) has not been fully elucidated. The objective of this study is to examine the influence of LIGHT on the development of myocardial fibrosis and AF. Methods: PCR arrays of peripheral blood mononuclear cells (PBMCs) from patients with AF and sinus rhythm was used to identify the dominant differentially expressed genes, followed by ELISA to evaluate its serum protein levels. Morphological, functional, and electrophysiological changes in the heart were detected in vivo after the tail intravenous injection of recombinant LIGHT (rLIGHT) in mice for 4 weeks. rLIGHT was used to stimulate bone marrow-derived macrophages (BMDMs) to prepare a macrophage-conditioned medium (MCM) in vitro. Then, the MCM was used to culture mouse cardiac fibroblasts (CFs). The expression of relevant proteins and genes was determined using qRT-PCR, western blotting, and immunostaining. Results: The mRNA levels of LIGHT and TNFRSF14 were higher in the PBMCs of patients with AF than in those of the healthy controls. Additionally, the serum protein levels of LIGHT were higher in patients with AF than those in the healthy controls and were correlated with left atrial reverse remodelling. Furthermore, we demonstrated that rLIGHT injection promoted macrophage infiltration and M2 polarisation in the heart, in addition to promoting atrial fibrosis and AF inducibility in vivo, as detected with MASSON staining and atrial burst pacing respectively. RNA sequencing of heart samples revealed that the PI3Kγ/SGK1 pathway may participate in these pathological processes. Therefore, we confirmed the hypothesis that rLIGHT promotes BMDM M2 polarisation and TGB-β1 secretion, and that this process can be inhibited by PI3Kγ and SGK1 inhibitors in vitro. Meanwhile, increased collagen synthesis and myofibroblast transition were observed in LIGHT-stimulated MCM-cultured CFs and were ameliorated in the groups treated with PI3Kγ and SGK1 inhibitors. Conclusion: LIGHT protein levels in peripheral blood can be used as a prognostic marker for AF and to evaluate its severity. LIGHT promotes cardiac fibrosis and AF inducibility by promoting macrophage M2 polarisation, wherein PI3Kγ and SGK1 activation is indispensable. [ABSTRACT FROM AUTHOR]

We present a case of bidirectional ventricular tachycardia in a 15-year-old boy asymptomatic for arrhythmias, whose major complaint was muscle weakness. At our first evaluation he was receiving sotalol for his ventricular arrhythmias. In addition to bidirectional tachycardia, electrocardiogram during sinus rhythm showed prominent U waves and prolonged QT-U interval. These electrocardiographic signs, along with the evidence of clinodactyly and mild hypertelorism, led us to the diagnosis of Andersen-Tawil syndrome, confirmed by genetic analysis that revealed a "de novo" missense mutation of KCNJ2 gene. Monotherapy with flecainide was rapidly effective and almost eliminated ventricular arrhythmias. After a 4-year follow-up there were no adverse events, flecainide has been well tolerated without significant modification of the QRS or repolarization, and ventricular arrhythmias have not been relapsed to date. The case highlights the importance of a correct clinical diagnosis, which is crucial for the optimal selection of the most appropriate drug therapy, which is expected not to be harmful, before being beneficial. [ABSTRACT FROM AUTHOR]

Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a rare inherited cardiac ion channelopathy where the initial disease presentation is during childhood or adolescent stages, leading to increased risks of sudden cardiac death. Despite advances in medical science and technology, several gaps remain in the understanding of the molecular mechanisms, risk prediction, and therapeutic management of patients with CPVT. Recent studies have identified and validated seven sets of genes responsible for various CPVT phenotypes, including RyR2, CASQ-2, TRDN, CALM1, 2, and 3, and TECRL, providing novel insights into the molecular mechanisms. However, more data on atypical CPVT genotypes are required to investigate the underlying mechanisms further. The complexities of the underlying genetics contribute to challenges in risk stratification as well as the uncertainty surrounding nongenetic modifiers. Therapeutically, although medical management involving beta-blockers and flecainide, or insertion of an implantable cardioverter defibrillator remains the mainstay of treatment, animal and stem cell studies on gene therapy for CPVT have shown promising results. However, its clinical applicability remains unclear. Current gene therapy studies have primarily focused on the RyR2 and CASQ-2 variants, which constitute 75% of all CPVT cases. Alternative approaches that target a broader population, such as CaMKII inhibition, could be more feasible for clinical implementation. Together, this review provides an update on recent research on CPVT, highlighting the need for further investigation of the molecular mechanisms, risk stratification, and therapeutic management of this potentially lethal condition. [ABSTRACT FROM AUTHOR]

Background: Palpitations represent a common cause for consultation in the pediatric Emergency Department (ED). Unlike adults, palpitations in children are less frequently dependent from the heart, recognizing other causes. Case presentation: A 11-year-old male came to our pediatric ED for epigastric pain, vomiting and palpitations. During the previous 6 month the patient was affected by SARS-CoV-2 (Severe Acute Respiratory Syndrome Coronavirus). Electrocardiogram (ECG) revealed supraventricular tachycardia. Therefore, adenosine was administered unsuccessfully. The administration of adenosine, however, allowed us to make diagnosis of atypical atrial flutter. Multiple attempts at both electrical cardioversion, transesophageal atrial overdrive, and drug monotherapy were unsuccessful in our patient. Consequently, a triple therapy with amiodarone, flecainide, and beta-blocker was gradually designed to control the arrhythmic pattern with the restoration of a left upper atrial rhythm. There was not any evidence of sinus rhythm in the patient clinical history. Conclusions: The present study underlines the rarity of this type of dysrhythmia in childhood and the difficulties in diagnosis and management, above all in a patient who has never showed sinus rhythm. Raising awareness of all available treatment options is essential for a better management of dysrhythmia in children [ABSTRACT FROM AUTHOR]

Background Ryanodine receptor 1 (RYR1)-related myopathies are a group of congenital muscle diseases caused by RYR1 mutations. These mutations may cause centronuclear myopathy, a congenital neuromuscular disorder characterized by clinical muscle weakness and pathological presence of centrally placed nuclei on muscle biopsy. Mutations in RYR2 cause ventricular arrhythmias that can be treated with flecainide; however, reports of ventricular arrhythmias in RYR1 -related myopathies are rare. Herein we report a case of centronuclear myopathy with RYR1 mutations who exhibited frequent premature ventricular contractions (PVCs) and non-sustained ventricular tachycardia (NSVT), which was successfully treated with verapamil and flecainide. Case summary At 7 months, the patient presented neurological manifestations of hypotonia and delayed motor development. A skeletal muscle biopsy performed at age 4 years led to the diagnosis of centronuclear myopathy. At age 15 years, frequent PVCs and NSVT were identified on the electrocardiogram and 24 h Holter monitoring. Treatment with verapamil was initiated; however, it was not beneficial. Therefore, flecainide was added to the treatment, decreasing the frequency of PVCs and NSVT. Non-sustained ventricular tachycardia disappeared at the age of 21, and PVCs almost disappeared at the age of 22. Genetic testing revealed c.13216delG (p.E4406Rfs*35), c.14874G>C (p.K4958N), and c.9892G>A (p.A3298T) in RYR1 , and the compound heterozygosity of variants was confirmed by analysis of the parents. Discussion This is the first report of ventricular arrhythmia associated with RYR1 -related myopathy that was successfully treated with verapamil and flecainide. The combination of verapamil and flecainide may be a useful treatment option for ventricular arrhythmias in patients with RYR1 -related myopathies. [ABSTRACT FROM AUTHOR]

Background: Beta‐blockers (BB) or dihydropyridine calcium channel blockers (CCBs) are still the first choices in the treatment of idiopathic premature ventricular complexes (PVCs), with low‐modest efficacy. Antiarrhythmic drugs (AADs) of Ic class are moderate to highly efficient but the evidence on their benefits is still limited. Aim: To compare effectiveness and safety of flecainide, propafenone, and sotalol in the treatment of symptomatic idiopathic PVCs. Methods: Our single‐center retrospective study analyzed 104 consecutive patients with 130 medication episodes of frequent idiopathic PVCs treated with AADs flecainide, propafenone (Ic class) or sotalol (III class). The primary outcome was complete/near complete reduction of PVCs after medication episode (PVCs burden reduction >99%), and the secondary outcome was significant PVC burden reduction (≥80%). Results: The complete/near complete PVCs burden reduction occurred in 31% and was significant in 43% of treated patients. A reduction of PVC burden for >99% was achieved in 56% of patients on flecainide, in 11% of patients on propafenone (p =.002), and in 21% of patients receiving sotalol (p =.031). There was no difference between propafenone and sotalol (p =.174). A reduction of PVC burden for ≥80% was achieved in 64% of patients on flecainide, in 30% of patients on propafenone (p =.009), and 33% of patients on sotalol (p =.020). There was no difference between propafenone and sotalol (p =.661). Conclusions: The efficacy of AADs class Ic and III in the treatment of idiopathic PVCs was modest. Flecainide was the most effective AAD in the achievement of complete/near complete or significant PVC burden reduction, compared to propafenone and sotalol. [ABSTRACT FROM AUTHOR]

Atrial fibrillation (AF) is the most common cardiac arrhythmia. Its treatment includes antiarrhythmic drugs (AADs) to modulate the function of cardiac ion channels. However, AADs have been limited by proarrhythmic effects, non-cardiovascular toxicities as well as often modest antiarrhythmic efficacy. Theoretical models showed that a combined blockade of Nav1.5 (and its current, INa) and Kv1.5 (and its current, IKur) ion channels yield a synergistic anti-arrhythmic effect without alterations in ventricles. We focused on Kv1.5 and Nav1.5 to search for structural similarities in their binding site (BS) for flecainide (a common blocker and widely prescribed AAD) as a first step for prospective rational multi-target directed ligand (MTDL) design strategies. We present a computational workflow for a flecainide BS comparison in a flecainide-Kv1.5 docking model and a solved structure of the flecainide-Nav1.5 complex. The workflow includes docking, molecular dynamics, BS characterization and pattern matching. We identified a common structural pattern in flecainide BS for these channels. The latter belongs to the central cavity and consists of a hydrophobic patch and a polar region, involving residues from the S6 helix and P-loop. Since the rational MTDL design for AF is still incipient, our findings could advance multi-target atrial-selective strategies for AF treatment.

Background: Despite successful mitral valve replacement (MVR), many patients remain in AF. Flecainide can be useful in these patients but has not been used because of underlying structural heart disease. Methods: We assessed oral flecainide for conversion and maintenance of SR in 25 patients of chronic rheumatic AF following MVR (age 34.4 yrs, mean AF duration: 3.6 yrs). Non-converters underwent DC cardioversion at 24 h and 4 weeks. Patients received flecainide and bb/diltiazem at discharge. Results: Single oral dose of Flecainide achieved SR in 6/25 (24%) while 19/25 achieved SR after DCC; at 24 h 21/25 (84%) were in SR. With mean flecainide dose (93.10 ± 9.40 mg), successful maintenance of SR at 6 months was seen in 16/23 (69.5%). No significant changes in PR interval, QRS duration or QTc were noted; flecainide was well tolerated. Patients in SR had significantly better functional status, QOL scores and higher LA strain at 6 months (25.25 vs 17.43%, p 21% for predicting SR were 87.5/71.43% and 100/85.71% respectively. Conclusion: Oral flecainide was safe and effective in post MVR rheumatic AF patients; maintenance of SR was achieved in 76% of initial converters and 64% of overall population, with better LA strain values. More studies are needed to validate these results.

Abstract Background Atrial flutter with 1:1 conduction to the ventricles is a dangerous cardiac arrhythmia. Contemporary guidelines recommend atrioventricular nodal blocking agents should be co-administered with class 1C anti-arrhythmics, as prophylaxis against 1:1 flutter. No guidance is provided on the type or strength of atrioventricular nodal blockade required, and in practice, these agents are frequently prescribed at low dose, or even omitted, due to their side effect profile. Case presentation A 62 year old Caucasian man with a history of paroxysmal atrial fibrillation treated with flecainide, presented with atrial flutter with 1:1 conduction to the ventricles and was cardioverted. Diltiazem was added to prevent this complication and he again presented with atrial flutter with 1:1 conduction to the ventricles, despite prophylaxis with coadministration of diltiazem. Conclusions This case report demonstrates failure of diltiazem to prevent 1:1 flutter in a patient chronically treated with flecainide for paroxysmal atrial fibrillation.

It is imperative to develop better approaches to predict how antiarrhythmic drugs with multiple interactions and targets may alter the overall electrical and/or mechanical function of the heart. Safety Pharmacology studies have provided new insights into the multi-target effects of many different classes of drugs and have been aided by the addition of robust new in vitro and in silico technology. The primary focus of Safety Pharmacology studies has been to determine the risk profile of drugs and drug candidates by assessing their effects on repolarization of the cardiac action potential. However, for decades experimental and clinical studies have described substantial and potentially detrimental effects of Na+ channel blockers in addition to their well-known conduction slowing effects. One such side effect, associated with administration of some Na+ channel blocking drugs is negative inotropy. This reduces the pumping function of the heart, thereby resulting in hypotension. Flecainide is a well-known example of a Na+ channel blocking drug, that exhibits strong rate-dependent block of INa and may cause negative cardiac inotropy. While the phenomenon of Na+ channel suppression and resulting negative inotropy is well described, the mechanism(s) underlying this effect are not. Here, we set out to use a modeling and simulation approach to reveal plausible mechanisms that could explain the negative inotropic effect of flecainide. We utilized the Grandi-Bers model [1] of the cardiac ventricular myocyte because of its robust descriptions of ion homeostasis in order to characterize and resolve the relative effects of QRS widening, flecainide off-target effects and changes in intracellular Ca2+ and Na+ homeostasis. The results of our investigations and predictions reconcile multiple data sets and illustrate how multiple mechanisms may play a contributing role in the flecainide induced negative cardiac inotropic effect.

Abstract Background Mothers requiring the antiarrhythmic agent flecainide are often advised not to breastfeed, because of the lack of data concercing neonatal effects and flecainide plasma concentrations following maternal exposure as well as via lactation. This is the first report on combined maternal, fetal, neonatal and breastmilk flecainide concentrations in a breastfed infant of a mother requiring flecainide treatment. Case presentation A 35-year old Gravida 2 Para 1, known with ventricular arrhythmia, was referred to our tertiary center at 35 + 4 weeks of gestation. Because of an increase of ventricular ectopy, oral metoprolol 11.9 milligrams once daily was switched to oral flecainide 87.3 milligrams twice daily. Weekly collected maternal flecainide plasma trough concentrations fell within the therapeutic range of 0.2 to 1.0 mg/L and no further clinically significant arrhythmias occurred during the study period. A healthy son was born at 39 weeks of gestation and had a normal electrocardiogram. The fetal to maternal flecainide ratio was 0.72 and at three different timepoints, the flecainide concentration was higher in breastmilk than in maternal plasma. The relative infant dose received via breastmilk compared to maternal dose was 5.6%. Neonatal plasma concentrations were not detectable, despite the flecainide passage into breastmilk. All electrocardiograms to assess the neonatal antiarrhytmic effect were normal. Conclusions Our results assume that flecainide can be prescribed safely to lactating mothers. Quantification of drug concentrations in neonatal blood in addition to measurements in maternal and fetal blood, and breastmilk, are helpful to evaluate the effects and safety of maternal medication use during pregnancy and lactation.

Arrhythmogenic cardiomyopathy (ACM) is a genetic disorder that may lead patients to sudden cell death through the occurrence of ventricular arrhythmias. ACM is characterised by the progressive substitution of cardiomyocytes with fibrofatty scar tissue that predisposes the heart to life-threatening arrhythmic events. Cardiac mesenchymal stromal cells (C-MSCs) contribute to the ACM by differentiating into fibroblasts and adipocytes, thereby supporting aberrant remodelling of the cardiac structure. Flecainide is an Ic antiarrhythmic drug that can be administered in combination with β-adrenergic blockers to treat ACM due to its ability to target both Nav1.5 and type 2 ryanodine receptors (RyR2). However, a recent study showed that flecainide may also prevent fibro-adipogenic differentiation by inhibiting store-operated Ca2+ entry (SOCE) and thereby suppressing spontaneous Ca2+ oscillations in C-MSCs isolated from human ACM patients (ACM C-hMSCs). Herein, we briefly survey ACM pathogenesis and therapies and then recapitulate the main molecular mechanisms targeted by flecainide to mitigate arrhythmic events, including Nav1.5 and RyR2. Subsequently, we describe the role of spontaneous Ca2+ oscillations in determining MSC fate. Next, we discuss recent work showing that spontaneous Ca2+ oscillations in ACM C-hMSCs are accelerated to stimulate their fibro-adipogenic differentiation. Finally, we describe the evidence that flecainide suppresses spontaneous Ca2+ oscillations and fibro-adipogenic differentiation in ACM C-hMSCs by inhibiting constitutive SOCE. [ABSTRACT FROM AUTHOR]

Background: Atrial flutter with 1:1 conduction to the ventricles is a dangerous cardiac arrhythmia. Contemporary guidelines recommend atrioventricular nodal blocking agents should be co-administered with class 1C anti-arrhythmics, as prophylaxis against 1:1 flutter. No guidance is provided on the type or strength of atrioventricular nodal blockade required, and in practice, these agents are frequently prescribed at low dose, or even omitted, due to their side effect profile. Case presentation: A 62 year old Caucasian man with a history of paroxysmal atrial fibrillation treated with flecainide, presented with atrial flutter with 1:1 conduction to the ventricles and was cardioverted. Diltiazem was added to prevent this complication and he again presented with atrial flutter with 1:1 conduction to the ventricles, despite prophylaxis with coadministration of diltiazem. Conclusions: This case report demonstrates failure of diltiazem to prevent 1:1 flutter in a patient chronically treated with flecainide for paroxysmal atrial fibrillation. [ABSTRACT FROM AUTHOR]

Abstract Brugada syndrome (BrS) may cause a spectrum of symptoms from asymptomatic patients to those who experience cardiac arrest and sudden cardiac death. The diagnosis is confirmed after observation of type I Brugada pattern on the electrocardiogram. Following the diagnosis, risk stratification can help select therapeutic options. Cascade screening should be started to find other family members with BrS. We present a 41-year-old woman diagnosed with BrS, and cascade screening of her relatives unveiled a pedigree of BrS among their family.

Atrial fibrillation has progressively become a more common reason for emergency department visits, representing 0.5% of presenting reasons. Registry data have indicated that about 60% of atrial fibrillation patients who present to the emergency department are admitted, emphasizing the need for more efficient management of atrial fibrillation in the acute phase. Management of atrial fibrillation in the setting of the emergency department varies between countries and healthcare systems. The most plausible reason to justify a conservative rather than an aggressive strategy in the management of atrial fibrillation is the absence of specific guidelines from diverse societies. Several trials of atrial fibrillation treatment strategies, including cardioversion, have demonstrated that atrial fibrillation in the emergency department can be treated safely and effectively, avoiding admission. In the present study, we present the epidemiology and characteristics of atrial fibrillation patients presenting to the emergency department, as well as the impact of diverse management strategies on atrial-fibrillation-related hospital admissions. Lastly, the design and initial data of the HEROMEDICUS protocol will be presented, which constitutes an electrophysiology-based aggressive rhythm control strategy in patients with atrial fibrillation in the emergency department setting.

Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a severe hereditary arrhythmia syndrome predominantly affecting children and young adults. It manifests through bidirectional or polymorphic ventricular arrhythmia, often culminating in syncope triggered by physical exertion or emotional stress which can lead to sudden cardiac death. Most cases stem from mutations in the gene responsible for encoding the cardiac ryanodine receptor (RyR2), or in the Calsequestrin 2 gene (CASQ2), disrupting the handling of calcium ions within the cardiac myocyte sarcoplasmic reticulum. Diagnosing CPVT typically involves unmasking the arrhythmia through exercise stress testing. This diagnosis emerges in the absence of structural heart disease by cardiac imaging and with a normal baseline electrocardiogram. Traditional first-line treatment primarily involves β-blocker therapy, significantly reducing CPVT-associated mortality. Adjunctive therapies such as moderate exercise training, flecainide, left cardiac sympathetic denervation and implantable cardioverter-defibrillators have been utilized with reasonable success. However, the spectrum of options for managing CPVT has expanded over time, demonstrating decreased rates of arrhythmic events. Furthermore, ongoing research into potential new therapies including gene therapies has the potential to further enhance treatment paradigms. This review aims to succinctly encapsulate the contemporary understanding of the clinical characteristics, diagnostic approach, established therapeutic interventions and the promising future directions in managing CPVT.

A 28-year-old female patient diagnosed with Ehlers-Danlos syndrome type III (hypermobile EDS, hEDS) was admitted to the cardiology clinic due to a 3-year history of symptomatic ventricular arrhythmia in the form of multiple premature ventricular contractions (PVCs). Attempts at antiarrhythmic treatment with beta-blockers, propafenone, and verapamil were unsuccessful. Due to the diagnosis of hEDS and the high risk of vascular complications related to the ablation procedure, invasive treatment was abandoned, and it was decided to implement flecainide. After the flecainide treatment initiation, a spectacular improvement in the number of ventricular arrhythmias was observed, along with the disappearance of the complaints previously reported by the patient. To the best of our knowledge, this is the first described case of spectacular flecainide antiarrhythmic effect in a patient with numerous PVCs also diagnosed with EDS. Flecainide treatment in the EDS group could be a successful alternative to ablation, which can lead to serious vascular and even life-threatening complications, especially after the failure of propafenone and beta-blockers treatment.

Pharmacologic cardioversion is a well-established alternative to electric cardioversion for hemodynamically stable patients, as it skips the risks associated with anesthesia. A recent network meta-analysis identifies the most effective antiarrhythmics for pharmacologic cardioversion with flecainide exhibiting a more efficacious and safer profile towards faster cardioversion. Moreover, the meta-analysis of class Ic antiarrhythmics revealed an absence of adverse events when used for pharmacologic cardioversion of AF in the ED, including patients with structural heart disease. The primary goals of this clinical trial are to prove the superiority of flecainide over amiodarone in the successful cardioversion of paroxysmal atrial fibrillation in the Emergency Department and to prove that the safety of flecainide is non-inferior to amiodarone in patients with coronary artery disease without residual ischemia, and an ejection fraction over 35%. The secondary goals of this study are to prove the superiority of flecainide over amiodarone in the reduction in hospitalizations from the Emergency Department due to atrial fibrillation in the time taken to achieve cardioversion, and in the reduction in the need to conduct electrical cardioversion. [ABSTRACT FROM AUTHOR]