Long-Term Outcomes of Brugada Substrate Ablation: A Report from BRAVO (Brugada Ablation of VF Substrate Ongoing Multicenter Registry).

Background: Treatment options for high-risk Brugada syndrome (BrS) with recurrent ventricular fibrillation (VF) are limited. Catheter ablation is increasingly performed but a large study with long-term outcome data is lacking. We report the results of the multicenter, international BRAVO (Brugada Ablation of VF Substrate Ongoing Registry) for treatment of high-risk symptomatic BrS.

Device-device interaction between cardiac implantable electronic devices and continuous-flow left ventricular assist devices.

The current design of an innovative left ventricular assist device (LVAD) makes use of magnetic levitation technology, which enables the rotors of the device to be completely suspended by magnetic force, reducing friction and blood or plasma damage. However, this electromagnetic field can result in electromagnetic interference (EMI), which can interfere with proper functioning of another cardiac implantable electronic device (CIED) in its direct proximity. Approximately 80% of patients with an LVAD have a CIED, most frequently an implantable cardioverter-defibrillator (ICD).

Comparison of and Frequency of Mortality, Left Ventricular Assist Device Implantation, Ventricular Arrhythmias, and Heart Transplantation in Patients With Familial Versus Nonfamilial Idiopathic Dilated Cardiomyopathy.

We postulated that familial idiopathic dilated cardiomyopathy (F-IDC) is associated with a worse prognosis than nonfamilial IDC (nonF-IDC). Patients with F-IDC had either a strong family history and/or proved genetic mutations. We studied long-term prognosis (mean follow-up: 6.

Clinical Benefit of Ablating Localized Sources for Human Atrial Fibrillation: The Indiana University FIRM Registry.

Background: Mounting evidence shows that localized sources maintain atrial fibrillation (AF). However, it is unclear in unselected "real-world" patients if sources drive persistent atrial fibrillation (PeAF), long-standing persistent atrial fibrillation (LPeAF), or paroxysmal atrial fibrillation (PAF); if right atrial sites are important; and what the long-term success of source ablation is.

Objectives: The aim of this study was to analyze the role of rotors and focal sources in a large academic registry of consecutive patients undergoing source mapping for AF.

Supraventricular tachycardia and sinus rhythm with contralateral bundle branch block patterns.

A contralateral bundle branch block (BBB) aberration during tachycardia with a preexisting BBB strongly suggests the presence of ventricular tachycardia. We report on a middle-aged, female patient presented with wide QRS tachycardia. The patient had orthodromic atrioventricular tachycardia with a left BBB aberration in the presence of a preexisting right BBB due to an abnormal His-Purkinje system.

Fragmented ECG as a risk marker in cardiovascular diseases.

Various noninvasive tests for risk stratification of sudden cardiac death (SCD) were studied, mostly in the context of structural heart disease such as coronary artery disease (CAD), cardiomyopathy and heart failure but have low positive predictive value for SCD. Fragmented QRS complexes (fQRS) on a 12-lead ECG is a marker of depolarization abnormality. fQRS include presence of various morphologies of the QRS wave with or without a Q wave and includes the presence of an additional R wave (R') or notching in the nadir of the R' (fragmentation) in two contiguous leads, corresponding to a major coronary artery territory.

Bi-ventricular pacing improves pump function only with adequate myocardial perfusion in canine hearts with pseudo-left bundle branch block.

Bi-ventricular (BiV) pacing is an effective therapy for the treatment of cardiac electromechanical (EM) dysfunction. The reason(s), however, for therapy non-response in approximately one-third of the subjects remains unclear, especially as it relates to myocardial perfusion and pacing location. In this study, we examined how acute BiV pacing response may be related to underlying myocardial perfusion coupled with pacing near or distant to the area of perfusion.

Simulation of mechanical environment in active lead fixation: effect of fixation helix size.

The risk of myocardial penetration due to active-fixation screw-in type pacing leads has been reported to increase as the helix electrodes become smaller. In order to understand the contributing factors for lead penetration, we conducted finite element analyses of acute myocardial micro-damage induced by a pacemaker lead screw-in helix electrode. We compared the propensity for myocardial micro-damage of seven lead designs including a baseline model, three modified designs with various helix wire cross-sectional diameters, and three modified designs with different helix diameters.

Delayed and indirect effects of antiarrhythmic drugs in reducing sudden cardiac death.

In the USA, two-thirds of sudden cardiac deaths (SCDs) are caused by sustained ventricular tachycardia and ventricular fibrillation. Implantable cardioverter defibrillator (ICD) therapy has been demonstrated to decrease mortality caused by these arrhythmias, when used both for primary and secondary prevention. However, ICD use is expensive, has proarrhythmic effects and does not prevent ventricular arrhythmias.

Simulation of LV pacemaker lead in marginal vein: potential risk factors for acute dislodgement.

Although left ventricular (LV) coronary sinus lead dislodgement remains a problem, the risk factors for dislodgement have not been clearly defined. In order to identify potential risk factors for acute lead dislodgement, we conducted dynamic finite element simulations of pacemaker lead dislodgement in marginal LV vein. We considered factors such as mismatch in lead and vein diameters, velocity of myocardial motion, branch angle between the insertion vein and the coronary sinus, degree of slack, and depth of insertion.

A novel approach to differentiating orthodromic reciprocating tachycardia from atrioventricular nodal reentrant tachycardia.

Background: Various diagnostic maneuvers have been proposed to help differentiate orthodromic reciprocating tachycardia (ORT) from atrioventricular nodal reentrant tachycardia (AVNRT) prior to ablation. However, not all criteria are applicable in every situation as each has limitations.

Objective: The purpose of this study was to determine whether the behavior of tachycardia during onset of right ventricular (RV) pacing would help differentiate ORT from AVNRT.

Segmental wall-motion abnormalities of the left ventricle predict arrhythmic events in patients with nonischemic cardiomyopathy.

Background: Nonischemic dilated cardiomyopathy (NICM) is associated with diffuse global hypokinesia on echocardiography. However, NICM also may be associated with segmental wall-motion abnormalities (SWMAs) even in the presence of global hypokinesia, probably secondary to patchy myocardial scars.

Objective: Because myocardial scars serve as substrate for reentry, the purpose of this study was to determine whether SWMA is a predictor of ventricular arrhythmic events in NICM.

Antiarrhythmic and nonantiarrhythmic drugs for sudden cardiac death prevention.

Life-threatening ventricular arrhythmias such as sustained ventricular tachycardia and ventricular fibrillation are responsible for two thirds of sudden cardiac deaths annually in the United States. Implantable cardioverter-defibrillator (ICD) therapy prevents mortality from arrhythmic death but is expensive and has some associated morbidity from proarrhythmia and mechanical malfunction. Furthermore, ICDs treat ventricular arrhythmias but do not prevent them.

Fragmented QRS on twelve-lead electrocardiogram predicts arrhythmic events in patients with ischemic and nonischemic cardiomyopathy.

Background: Myocardial scar is a substrate for reentrant ventricular arrhythmias and is associated with poor prognosis. Fragmented QRS (fQRS) on 12-lead ECG represents myocardial conduction delays due to myocardial scar in patients with coronary artery disease (CAD).

Objective: The purpose of this study was to determine whether fQRS is associated with increased ventricular arrhythmic event and mortality in patients with CAD and nonischemic dilated cardiomyopathy (DCM).

Focal mechanism of ventricular tachycardia in coronary artery disease.

Background: Re-entry is the most common mechanism of sustained monomorphic ventricular tachycardia (VT) in patients with coronary artery disease and prior myocardial infarction (MI).

Objective: This study sought to report the electrophysiological properties of a series of patients with prior MI who underwent radiofrequency ablation (RFA) for VT originating instead from a focal source.

Methods: The electrophysiological properties of 46 patients with prior MI (male 89%, age 64.

Usefulness of fragmented QRS on a 12-lead electrocardiogram in acute coronary syndrome for predicting mortality.

Electrocardiographic signs of a non-ST elevation myocardial infarction (NSTEMI) are nonspecific, and therefore the diagnosis of NSTEMI during acute coronary syndromes (ACS) depends mainly on cardiac biomarker levels. Fragmented QRS (fQRS) represents myocardial conduction abnormalities due to myocardial infarction (MI) scars in patients with coronary artery disease. However, the time of appearance of fQRS during ACS has not been investigated.

Mechanisms of sinoatrial node dysfunction in a canine model of pacing-induced atrial fibrillation.

Background: The mechanism of sinoatrial node (SAN) dysfunction in atrial fibrillation (AF) is unclear.

Objective: The purpose of this study was to test the hypothesis that defective spontaneous sarcoplasmic reticulum (SR) Ca(2+) release (Ca(2+) clock) is in part responsible for SAN dysfunction in AF.

Methods: Arrhythmic events and SAN function were evaluated in pacing-induced AF dogs (n = 7) and in normal dogs (n = 19) with simultaneous intracellular calcium (Ca(i)) and membrane potential recording.

Fragmented QRS and other depolarization abnormalities as a predictor of mortality and sudden cardiac death.

Purpose Of Review: Several invasive and noninvasive tests for risk stratification of sudden cardiac death (SCD) have been studied. Tests such as microwave T wave alternans (repolarization abnormality) and signal-averaged ECG (depolarization abnormality) have high negative predictive values but low positive predictive values in patients with heart disease. The presence of a fragmented QRS (fQRS) complex on a routine 12-lead ECG is another marker of depolarization abnormality.

Fragmented wide QRS on a 12-lead ECG: a sign of myocardial scar and poor prognosis.

Background: Fragmented QRS (duration <120 ms) on a 12-lead ECG represents myocardial scar in patients with coronary artery disease. However, the significance of fragmented QRS has not been defined in the presence of a wide QRS (wQRS; duration >or=120 ms). We postulate that fragmented wQRS (f-wQRS) due to bundle branch block, premature ventricular complexes, or paced rhythms (f-pQRS) signify myocardial scar and higher mortality.

Fragmented QRS complexes on 12-lead ECG: a marker of cardiac sarcoidosis as detected by gadolinium cardiac magnetic resonance imaging.

Background: Fragmented QRS complexes (fQRS) on a 12-lead ECG are a marker of myocardial scar in patients with coronary artery disease. Cardiac sarcoidosis is also associated with myocardial granuloma formation and scarring. We evaluated the significance of fQRS on a 12-lead ECG compared to Gadolinium-delayed enhancement images (GDE) in cardiac magnetic resonance imaging (CMR).