High Risk of Sustained Ventricular Arrhythmia Recurrence After Acute Myocarditis.

Acute myocarditis is associated with cardiac arrhythmia in 25% of cases; a third of these arrhythmias are ventricular tachycardia (VT) or ventricular fibrillation (VF). The implantation of a cardiac defibrillator (ICD) following sustained ventricular arrhythmia remains controversial in these patients. We sought to assess the risk of major arrhythmic ventricular events (MAEs) over time in patients implanted with an ICD following sustained VT/VF in the acute phase of myocarditis compared to those implanted for VT/VF occurring on myocarditis sequelae.

Atrial premature activity detected after an ischaemic stroke unveils atrial myopathy.

Background: Recent publications suggest that left atrial (LA) myopathy is a potential source of thromboembolism, independent of atrial fibrillation.

Aims: We sought to investigate whether the presence of atrial premature activity after an ischaemic stroke is associated with LA remodelling and dysfunction, and might be a surrogate marker of LA myopathy.

Methods: After an ischaemic stroke or a transient ischaemic attack, patients without known atrial fibrillation or overt heart disease were included prospectively in the study.

Flecainide is a safe and effective treatment for pre-excited atrial fibrillation rapidly conducted to the ventricle in pregnant women: a case series.

Background: Pregnancy is associated with an increased incidence of cardiac arrhythmias likely due to hormonal, haemodynamic, and autonomic changes. Yet, there is little data available regarding the efficacy and safety of anti-arrhythmic agents to prevent pre-excited atrial fibrillation (AF) in pregnant women.

Case Summary: We report on three pregnant women who developed AF rapidly conducted to the ventricle through an overt accessory pathway as the first manifestation of Wolff-Parkinson-White syndrome.

Atrial Structural Remodeling Gene Variants in Patients with Atrial Fibrillation.

Atrial fibrillation (AF) is a common arrhythmia for which the genetic studies mainly focused on the genes involved in electrical remodeling, rather than left atrial muscle remodeling. To identify rare variants involved in atrial myopathy using mutational screening, a high-throughput next-generation sequencing (NGS) workflow was developed based on a custom AmpliSeq™ panel of 55 genes potentially involved in atrial myopathy. This workflow was applied to a cohort of 94 patients with AF, 76 with atrial dilatation and 18 without.

First identification of homozygous truncating CSRP3 variants in two unrelated cases with hypertrophic cardiomyopathy.

Hypertrophic cardiomyopathy (HCM) is the most common inherited cardiovascular disease with an estimated prevalence of 1/500. More than 40 genes have been reported to cause HCM. Among them, CSRP3 is usually included on HCM gene panels used for molecular diagnosis by next-generation sequencing (NGS).

Delayed diagnosis of Brugada syndrome in a patient with aborted sudden cardiac death and initial negative flecainide challenge.

A negative flecainide challenge does not rule out Brugada syndrome even in the presence of nonfatal cardiac arrest as the first manifestation of the disease. This should prompt clinicians to ensure long-term ECG follow-up and consider repeating a drug test with another sodium channel blocker.

Additional coronary sinus shocking lead as rescue therapy after multiple internal and external defibrillation failures.

High defibrillation threshold (DFT) and defibrillation failure can lead to intractable ventricular arrhythmias. Additional coronary sinus coil is an effective strategy to achieve marked reduction in DFT. However, physicians should retain this might prevent future coronary sinus lead placement in case the patient would develop complete left bundle branch block.

Induced Pluripotent Stem Cell-Derived Cardiomyocytes Provide In Vivo Biological Pacemaker Function.

Background: Although multiple approaches have been used to create biological pacemakers in animal models, induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) have not been investigated for this purpose. We now report pacemaker function of iPSC-CMs in a canine model.

Methods And Results: Embryoid bodies were derived from human keratinocytes, their action potential characteristics determined, and their gene expression profiles and markers of differentiation identified.

Increased Late Sodium Current Contributes to the Electrophysiological Effects of Chronic, but Not Acute, Dofetilide Administration.

Background: Drugs are screened for delayed rectifier potassium current (IKr) blockade to predict long QT syndrome prolongation and arrhythmogenesis. However, single-cell studies have shown that chronic (hours) exposure to some IKr blockers (eg, dofetilide) prolongs repolarization additionally by increasing late sodium current (INa-L) via inhibition of phosphoinositide 3-kinase. We hypothesized that chronic dofetilide administration to intact dogs prolongs repolarization by blocking IKr and increasing INa-L.

Interventricular dispersion in repolarization causes bifid T waves in dogs with dofetilide-induced long QT syndrome.

Background: Long QT2 (LQT2) syndrome is characterized by bifid (or notched) T waves, whose mechanism is not understood.

Objective: The purpose of this study was to test whether increased interventricular dispersion of repolarization induces bifid T waves.

Methods: We simultaneously recorded surface ECG and unipolar electrograms at baseline and after dofetilide in a canine model of dofetilide-induced LQT2 (6 male mongrel dogs).

Stem cell-based biological pacemakers from proof of principle to therapy: a review.

Electronic pacemakers are the standard therapy for bradycardia-related symptoms but have shortcomings. Over the past 15 years, experimental evidence has demonstrated that gene and cell-based therapies can create a biological pacemaker. Recently, physiologically acceptable rates have been reported with an adenovirus-based approach.

Periatrial epicardial fat is associated with markers of endothelial dysfunction in patients with atrial fibrillation.

Background: Epicardial adipose tissue (EAT) is associated to atrial fibrillation (AF) burden and outcome after AF ablation. We intended to determine whether global or local EAT is associated with systemic and/or left atrial (LA) inflammation and markers of endothelial dysfunction in AF patients.

Methods And Results: Total, atrial, and ventricular EAT volume (EAT total, EAT atrial, EAT ventricular) were measured by multislice cardiac CT in 49 patients with paroxysmal (PAF, n=25) or persistent AF (PeF, n=24).

Persistent abnormal intraventricular conduction after myocarditis revealed by recurrent syncopes.

A 24-year-old male was admitted to our hospital for recurrent syncopes. Several ECG showed paroxysmal second degree atrioventricular block with the QRS axis changing between conducted beats and escape beats. Transvenous cardiac pacing was performed until permanent recapture of atrioventricular conduction (day 4).