Heart Rhythm: the Official Journal of the Heart Rhythm Society

BACKGROUND: Recurrences of atrial fibrillation (AF) after ablation have been attributed to conduction gaps and non-transmural ablation lesions OBJECTIVE: To assess the feasibility of adjunctive percutaneous mapping of the epicardial regions of the left atrium to characterize the transmural extent of substrate and ablation lesions. METHODS: Between 2014-2018, combined epi-endo mapping of AF was performed in 18 patients via inferior subxiphoid percutaneous approach (16 with previously failed ablations, and 2 patients with long-standing persistent AF) at 2 centers...

No abstract text is available yet for this article.

BACKGROUND: Atrial fibrillation (AF) is common after pacemaker implantation. Nevertheless, the impact of pacemaker algorithms in AF prevention is not well understood. OBJECTIVES: To evaluate the role of pacing algorithms in preventing AF progression. METHODS: A systematic search of articles using PUBMED and EMBASE database resulted in a total of 754 references. After exclusions, 21 randomized controlled trials (8,336 patients) were analysed, comprising studies reporting ventricular pacing percentage (VP%) (AAI vs DDD, n=1; and reducing ventricular pacing (RedVP) algorithms, n=2), atrial pacing therapies (atrial preference pacing (APP), n=14; antitachycardia pacing (aATP)+APP,n=3; and RedVP+APP+aATP,n=1)...

BACKGROUND: Internal insulation breaches (IBR) may result ICD lead failure and adverse clinical events. Concerns exist that the Durata lead may be prone to IBR. OBJECTIVE: Assess Durata failures in the FDA MAUDE database and compare them to failures in MAUDE for Endotak Reliance (ER) and Sprint Quattro Secure (QS) leads. METHODS: We searched the MAUDE database from 2008-2018 for IBR and other failure modes. Included were explanted leads whose manufacturers found an insulation or conductor defect not caused by extrinsic factors...

Cardiac K+ -channelopathies account for a significant proportion of arrhythmias and sudden cardiac death (SCD) in subjects without structural heart disease. It is well recognized that genetic defects are key factors in many cases and in practice, the term cardiac channelopathies currently coincides with that of inherited cardiac channelopathies. However, mounting evidence demonstrate that not only genetic alterations but also autoimmune and inflammatory factors can cause cardiac K+ -channel dysfunction and arrhythmias in the setting of a structurally normal heart...

No abstract text is available yet for this article.

BACKGROUND: Fasciculoventricular fibers (FVFs) are responsible for 1-5% of cases of asymptomatic pre-excitation on surface electrocardiogram (ECG). Unlike ventricular pre-excitation seen in Wolff-Parkinson-White (WPW) syndrome, FVFs are not associated with sudden cardiac death from pre-excited atrial fibrillation. OBJECTIVE: To identify surface ECG variables that differentiate FVFs from true WPW syndrome. METHODS: Retrospective case-control study comparing surface ECG characteristics in patients diagnosed with a FVF (cases) to WPW patients with anteroseptal accessory pathways (APs; controls) via intracardiac electrophysiology (EP) testing at a single institution from 2005-2017...

BACKGROUND: Atrial fibrillation (AF) triggers within the coronary sinus (CS)/great cardiac vein (GCV) and the left atrial appendage (LAA) have been recognized as non-pulmonary veins (PV) triggers of AF. OBJECTIVE: The aim of our study is to report unusual pattern of LAA electrical isolation (LAAEI). METHODS: 488 consecutive patients undergoing catheter ablation for persistent or long standing persistent AF who showed firing from the LAA and or from the CS/GCV have been enrolled in this multicenter prospective study...

BACKGROUND: Catecholamingergic polymorphic ventricular tachycardia (CPVT) is characterized by adrenergically-induced VT, syncope, and sudden cardiac arrest (SCA). In the absence of structural disease, exercise-provoked premature ventricular contractions in bigeminy/couplets and non-sustained VT are highly predictive of CPVT. OBJECTIVE: To determine the number of missed/delayed CPVT diagnoses attributable to exercise testing oversights in a cohort of young SCA survivors...

No abstract text is available yet for this article.

No abstract text is available yet for this article.

No abstract text is available yet for this article.

No abstract text is available yet for this article.

Much has been written about arrhythmias in structurally normal hearts. Here we have focused on rapid ventricular arrhythmias that occur in hearts where a pathogenic genetic variant has been found in families in which arrhythmias occur. We discuss these mutations in terms of their effect on cardiac cell electrical function and initiation of arrhythmias (see Supplement). In addition, we have focused on the Purkinje cell, their anatomic networks and molecular signatures as the sites of origin of arrhythmias. We discuss therapeutic options for these potentially life-threatening arrhythmias...

BACKGROUND: Triggers for discrete atrial fibrillation (AF) events remain poorly studied and incompletely characterized. OBJECTIVE: The present study describes common triggers for AF and their relationships with patient characteristics. METHODS: We invited symptomatic, paroxysmal AF patients enrolled in the Health eHeart Study and through the patient-centered advocacy organization StopAfib.org to complete a questionnaire regarding their AF triggers and cardiovascular risk factors...

BACKGROUND: Dofetilide is a commonly used class III anti-arrhythmic drug for atrial fibrillation. Drug guidelines mandates waiting for 3-month prior to initiating dofetilide after amiodarone use. It is not known if patients with implantable cardioverter defibrillator (ICD) can be rapidly switched from amiodarone to dofetilide. OBJECTIVE: We aimed to evaluate if rapid switching of amiodarone to dofetilide is safe in atrial fibrillation patients with ICD. METHODS: In this retrospective observational study, we assessed the feasibility as well as short- and long-term safety of rapid switching from amiodarone to dofetilide in hospitalized patients with atrial fibrillation with an ICD...

BACKGROUND: Catheter ablation for polymorphic ventricular tachycardia and ventricular fibrillation (PMVT/VF) may target triggering premature ventricular contractions (PVCs). Targeting ventricular scar has also been suggested but data are limited. OBJECTIVE: Characterize the electrophysiologic findings and ablation outcomes for patients with PMVT/VF and structural heart disease, compared to those with idiopathic VF. METHODS: Data from 32 consecutive patients (13 idiopathic VF and 19 structural heart disease (SHD)) with recurrent PMVT/VF who underwent catheter ablation were reviewed...

BACKGROUND: Increased CO2 levels in general circulation and/or in the myocardium are common under pathological conditions. OBJECTIVE: To test the hypothesis that an increase in CO2 levels, but not just the subsequent extra- or intra-cellular acidosis, would augment late sodium current (INa,L ), and contribute to arrhythmogenesis in hearts with reduced repolarization reserve. METHODS: Monophasic action potential durations at 90% completion of repolarization (MAPD90 ) from isolated rabbit hearts, INa,L and extra- (pHo ) and intra-cellular pH (pHi ) values from cardiomyocytes using the whole-cell patch-clamp techniques and BCECF-AM, respectively, were measured...

BACKGROUND: Cardiac resynchronization therapy (CRT) reduces morbidity and mortality in selected heart failure patients but decision-making regarding selection of CRT-defibrillator or CRT-pacemaker is an ongoing debate. OBJECTIVE: Aim was to construct predictive models and scoring systems for "ICD-therapy" and "death without ICD-therapy (prior death)". METHODS: We pooled two prospective cohorts of CRT-D patients with primary prevention indication and used Fine and Gray models to develop independent prognostic models for time to first ICD-therapy (event of interest) or death without prior ICD-therapy (competing event)...

BACKGROUND: The left atrial myocardium (LAM) and coronary sinus (CS) musculature (CSM) generate atrial electrograms recorded inside the CS (AECSs). The vein of Marshall (VOM) courses the mitral isthmus (MI) and VOM ethanol infusion (EI-VOM) is useful to ablate it. Its detailed effect on the MI, which contains LAM, CSM and those connections, is unknown. OBJECTIVE: To investigate the impact of EI-VOM on the MI by assessing the AECS. METHODS: Eighty-four consecutive patients with atrial fibrillation undergoing MI ablation with successful EI-VOM were included...