Pectus excavatum: uncommon electrical abnormalities caused by extrinsic right ventricular compression.

We report a case of pectus excavatum associated with ventricular tachycardia provoked by exercise in a 19-year-old man. Although this chest deformity has been associated with supraventricular dysrhythmias, documented ventricular tachycardia has only been reported once. Our patient's ventricular dysrhythmia was treated by surgical correction of his pectus excavatum only, and at 3 years follow-up he has had no recurrence of his ventricular tachycardia.

Catheter ablation of ventricular fibrillation storm in a long QT syndrome genotype carrier with normal QT interval.

Patients with long QT syndrome can sometimes present with a ventricular fibrillation (VF) storm. Catheter ablation of culprit premature ventricular complexes responsible for the triggering of the VF episodes may be required in rare cases of electrical storm that do not respond to conventional measures, and this can be life-saving. We describe a case of emergency catheter ablation in a young woman with a normal corrected QT interval, who presented with malignant VF storm for the first time.

Catheter ablation of ventricular fibrillation triggers and electrical storm.

Ventricular fibrillation (VF) and electrical storm remain challenging conditions to manage despite the availability of various treatment modalities. Insertion of an implantable cardioverter defibrillator (ICD) remains the gold standard method for lowering the risk of sudden cardiac death in patients deemed to be at greatest risk of ventricular arrhythmias. However, ICDs do not alter the underlying substrate responsible for the arrhythmic events and a significant proportion of patients with ICDs may experience VF storm which may be life threatening and difficult to control with medication.

Complete atrioventricular block complicating acute anterior myocardial infarction can be reversed with acute coronary angioplasty.

Introduction: A retrospective case series of acute anterior myocardial infarction (MI) patients complicated by complete atrioventricular block (AVB) treated with acute percutaneous transluminal coronary angioplasty (PTCA).

Clinical Picture: Eight patients with anterior MI and complete AVB underwent acute PTCA between 2000 and 2005. Mean onset of complete AVB was 16.

Outcomes of long-standing persistent atrial fibrillation ablation: a systematic review.

Background: Ablation of long-standing persistent atrial fibrillation (AF) is highly variable, with differing techniques and outcomes.

Objective: The purpose of this study was to undertake a systematic review of the literature with regard to the impact of ablation technique on the outcomes of long-standing persistent AF ablation.

Methods: A systematic search of the contemporary English scientific literature (from January 1, 1990 to June 1, 2009) in the PubMed database identified 32 studies on persistent/long-standing persistent or long-standing persistent AF ablation (including four randomized controlled trials).

Comprehensive mutation scanning of KCNQ1 in 111 Han Chinese patients with lone atrial fibrillation.

Objective: To determine the extent to which genetic variation in the potassium channel gene KCNQ1 causes atrial fibrillation (AF).

Design: Case-control study.

Setting: National University Hospital, Singapore.

Implantation of lumenless pacing leads at the inter-atrial septum and right ventricular outflow tract with deflectable catheter-sheath.

Current permanent right ventricular and right atrial endocardial pacing leads are implanted utilizing a central lumen stylet. Right ventricular apex pacing initiates an abnormal asynchronous electrical activation pattern, which results in asynchronous ventricular contraction and relaxation. When pacing from right atrial appendage, the conduction time between two atria will be prolonged, which results in heterogeneity for both depolarization and repolarization.

Complete isolation of the pulmonary veins and posterior left atrium in chronic atrial fibrillation. Long-term clinical outcome.

Aims: To evaluate the contribution of the posterior left atrium (LA) to chronic atrial fibrillation (AF).

Methods And Results: Twenty-seven patients with chronic-AF were studied. After pulmonary vein (PV) isolation, the posterior-LA was isolated by ablation joining the right- and left-PVs using an irrigated-tip catheter.

Loss-of-function mutations in the cardiac calcium channel underlie a new clinical entity characterized by ST-segment elevation, short QT intervals, and sudden cardiac death.

Background: Cardiac ion channelopathies are responsible for an ever-increasing number and diversity of familial cardiac arrhythmia syndromes. We describe a new clinical entity that consists of an ST-segment elevation in the right precordial ECG leads, a shorter-than-normal QT interval, and a history of sudden cardiac death.

Methods And Results: Eighty-two consecutive probands with Brugada syndrome were screened for ion channel gene mutations with direct sequencing.

Impact of left ventricular epicardial and biventricular pacing on ventricular repolarization in normal-heart individuals and patients with congestive heart failure.

Aims: Malignant ventricular arrhythmias can arise in a subset of congestive heart failure (CHF) patients after they undergo cardiac resynchronization therapy (CRT), thus counteracting the haemodynamic benefits typically associated with biventricular pacing. This study seeks to assess whether alteration of the ventricular transmural repolarization and conduction due to reversal of the depolarization sequence during epicardial or biventricular pacing facilitate the development of ventricular arrhythmias.

Methods And Results: ECGs and monophasic action potential (MAP) were recorded during programmed stimulation from right ventricle (RV) endocardium (RV-Endo), left ventricle (LV) epicardium (LV-Epi), or both (biventricular, Bi-V) in 15 individuals without structural heart diseases.

Frequency mapping of the pulmonary veins in paroxysmal versus permanent atrial fibrillation.

Introduction: The pulmonary veins (PVs) are a dominant source of triggers initiating atrial fibrillation (AF). While recent evidence implicates these structures in the maintenance of paroxysmal AF, their role in permanent AF is not known. The current study aims to compare the contribution of PV activity to the maintenance of paroxysmal and permanent AF.

Characterization of conduction recovery across left atrial linear lesions in patients with paroxysmal and persistent atrial fibrillation.

Background: Left atrial (LA) linear lesions are effective in substrate modification for atrial fibrillation (AF). However, achievement of complete conduction block remains challenging and conduction recovery is commonly observed. The aim of the study was to investigate the localization of gap sites of recovered LA linear lesions.

Fibrillating areas isolated within the left atrium after radiofrequency linear catheter ablation.

Introduction: Nonpulmonary vein sources have been implicated as potential drivers of atrial fibrillation (AF). This observational study describes regions of fibrillating atrial tissue isolated inadvertently from the left atrium (LA) following linear catheter ablation for AF.

Methods And Results: We report four patients with persistent/permanent AF who underwent pulmonary vein isolation with additional linear lesions and who presented with recurrent AF (mean AF cycle length [AFCL] 175-270 ms).

Phrenic nerve injury after atrial fibrillation catheter ablation: characterization and outcome in a multicenter study.

Objectives: The purpose of this study was to characterize the occurrence of phrenic nerve injury (PNI) and its outcome after radiofrequency (RF) ablation of atrial fibrillation (AF).

Background: It is recognized that extra-myocardial damage may develop owing to penetration of ablative energy.

Methods: Between 1997 and 2004, 3,755 consecutive patients underwent AF ablation at five centers.

Flutter localized to the anterior left atrium after catheter ablation of atrial fibrillation.

Introduction: Organized atrial arrhythmias following atrial fibrillation (AF) ablation are typically due to recovered pulmonary vein (PV) conduction or reentry at incomplete ablation lines. We describe the role of nonablated anterior left atrium (LA) in arrhythmias observed after AF ablation.

Methods: A total of 275 consecutive patients with paroxysmal (n = 200) or chronic (n = 75) AF had PV isolation with/without additional linear ablation at the mitral isthmus (n = 106), LA roof (n = 23), or both (n = 88).

Shortening of fibrillatory cycle length in the pulmonary vein during vagal excitation.

Objectives: The goal of the present prospective study is to evaluate the impact of vagal excitation on ongoing atrial fibrillation (AF) during pulmonary vein (PV) isolation.

Background: The role of vagal tone in maintenance of AF is controversial in humans.

Methods: Twenty-five patients (18 with paroxysmal AF, 7 with chronic AF) were selected by occurrence of vagal excitation during AF (atrioventricular [AV] block: R-R interval >3 s) produced by PV isolation.

Localized sources maintaining atrial fibrillation organized by prior ablation.

Background: Endocardial mapping of localized sources driving atrial fibrillation (AF) in humans has not been reported.

Methods And Results: Fifty patients with AF organized by prior pulmonary vein and linear ablation were studied. AF was considered organized if mapping during AF showed irregular but discrete atrial complexes exhibiting consistent activation sequences for >75% of the time using a 20-pole catheter with 5 radiating spines covering 3.

Long-term evaluation of atrial fibrillation ablation guided by noninducibility.

Background: Pulmonary vein (PV) isolation and linear lesions are effective in eliminating paroxysmal atrial fibrillation (AF), but linear lesions probably are not required in all patients. Noninducibility of AF has been shown to be associated with freedom from arrhythmia in 87% of patients.

Objectives: The purpose of this study was to prospectively evaluate the role of noninducibility in guiding a stepwise approach tailored to the patient.

Clinical predictors of noninducibility of sustained atrial fibrillation after pulmonary vein isolation.

Background: Noninducibility of sustained atrial fibrillation (AF) after pulmonary vein isolation (PVI) has been shown to be associated with a better clinical outcome. We evaluated the role of clinical variables that could predict noninducibility of sustained AF after PVI.

Methods And Results: Data were collected prospectively from 181 patients (153 male; age 54 +/- 9 years) referred for ablation of drug-refractory symptomatic paroxysmal AF (duration < or =7 days).

High-density activation mapping of fractionated electrograms in the atria of patients with paroxysmal atrial fibrillation.

Background: Areas of complex fractionated atrial electrograms (CFAEs) have been implicated in the atrial substrate of atrial fibrillation (AF). The mechanisms underlying CFAE in humans are not well investigated.

Objectives: The purpose of this study was to investigate the regional activation pattern associated with CFAE using a high-density contact mapping catheter.