Acute Hemodynamic Effects of Biventricular Pacing After Left Ventricular Assist Device.

Background: Despite cardiac resynchronization therapy (CRT), some patients with heart failure progress and undergo left ventricular assist device (LVAD) implantation. Management of CRT after LVAD implantation has not been well studied. The purpose of this study was to determine whether RV pacing or biventricular pacing measurably affects acute hemodynamics in patients with an LVAD and a CRT device.

Safety and Efficacy of Uninterrupted Apixaban Therapy Versus Warfarin During Atrial Fibrillation Ablation.

Thromboembolic cerebrovascular accident remains a rare but potentially devastating complication of catheter-based atrial fibrillation (AF) ablation. Uninterrupted oral anticoagulant therapy with warfarin has become the standard of care when performing catheter-based AF ablation. Compared with warfarin, apixaban, a factor Xa inhibitor, has been shown to reduce the risk of stroke and major bleeding in nonvalvular AF.

Significant Discrepancy Between Estimated and Actual Longevity in St. Jude Medical Implantable Cardioverter-Defibrillators.

Background: Real-time estimated longevity has been reported in pacemakers for several years, and was recently introduced in implantable cardioverter-defibrillators (ICDs).

Objective: We sought to evaluate the accuracy of this longevity estimate in St. Jude Medical (SJM) ICDs, especially as the device battery approaches depletion.

Prevalence and Electrocardiographic and Electrophysiological Characteristics of Idiopathic Ventricular Arrhythmias Originating From Intramural Foci in the Left Ventricular Outflow Tract.

Backgrounds: Idiopathic ventricular arrhythmias (VAs) originating from the left ventricular outflow tract (LVOT) sometimes require catheter ablation from both the endocardial and epicardial sides for their elimination, suggesting the presence of intramural VA foci. This study investigated the prevalence and electrocardiographic and electrophysiological characteristics of these idiopathic intramural LVOT VAs when compared with the idiopathic endocardial and epicardial LVOT VAs.

Methods And Results: We studied 82 consecutive VAs with origins in the aortomitral continuity (n=30), LV summit (n=34), and intramural site (n=18).

Radiofrequency catheter ablation of idiopathic ventricular arrhythmias originating from intramural foci in the left ventricular outflow tract: efficacy of sequential versus simultaneous unipolar catheter ablation.

Backgrounds: Idiopathic ventricular arrhythmias (VAs) originating from the left ventricular outflow tract (LVOT) sometimes require catheter ablation from the endocardial and epicardial sides for their elimination, suggesting the presence of intramural VA foci. This study investigated the efficacy of sequential and simultaneous unipolar radiofrequency catheter ablation from the endocardial and epicardial sides in treating intramural LVOT VAs.

Methods And Results: Fourteen consecutive LVOT VAs, which required sequential or simultaneous irrigated unipolar radiofrequency ablation from the endocardial and epicardial sides for their elimination, were studied.

A novel electrocardiographic criterion for differentiating a left from right ventricular outflow tract tachycardia origin: the V2S/V3R index.

Introduction: Although several ECG criteria have been proposed for differentiating between left and right origins of idiopathic ventricular arrhythmias (VA) originating from the outflow tract (OT-VA), their accuracy and usefulness remain limited. This study was undertaken to develop a more accurate and useful ECG criterion for differentiating between left and right OT-VA origins.

Methods And Results: We studied OT-VAs with a left bundle branch block pattern and inferior axis QRS morphology in 207 patients who underwent successful catheter ablation in the right (RVOT; n = 154) or left ventricular outflow tract (LVOT; n = 53).

Prevalence and clinical, electrocardiographic, and electrophysiologic characteristics of ventricular arrhythmias originating from the noncoronary sinus of Valsalva.

Background: Idiopathic ventricular arrhythmias (VAs) can be rarely ablated from the noncoronary cusp (NCC) of the aorta.

Objective: The purpose of this study was to investigate the prevalence and the clinical, electrocardiographic, and electrophysiologic characteristics of idiopathic NCC VAs.

Methods: We studied 90 consecutive patients who underwent successful catheter ablation of idiopathic aortic root VAs (left coronary cusp [LCC] 33, right coronary cusp [RCC] 32, junction between LCC and RCC 19, NCC = 6).

Cardiovascular implantable electronic device implantation with uninterrupted dabigatran: comparison to uninterrupted warfarin.

Background: While continuation of oral anticoagulation (OAC) with warfarin may be preferable to interruption and bridging with heparin for patients undergoing cardiovascular implantable electronic device (CIED) implantation, it is uncertain whether the same strategy can be safely used with dabigatran.

Objective And Methods: To determine the risk of bleeding and thromboembolic complications associated with uninterrupted OAC during CIED implantation, replacement, or revision, the outcomes of patients receiving uninterrupted dabigatran (D) were compared to those receiving warfarin (W).

Results: D was administered the day of CIED implant in 48 patients (age 66 ± 12.

Dabigatran versus warfarin therapy for uninterrupted oral anticoagulation during atrial fibrillation ablation.

Background: Uninterrupted oral anticoagulant (OA) therapy with warfarin has become the standard of care at many centers performing catheter ablation of atrial fibrillation (AF). Compared with warfarin, dabigatran, a direct thrombin inhibitor, has been demonstrated to reduce the risk of stroke in nonvalvular AF with similar bleeding risk. Few data exist on the safety profile of uninterrupted dabigatran therapy during AF ablation.

Arrhythmias in Fabry cardiomyopathy.

Background: Prior studies suggest that the incidence of ventricular arrhythmias is high in patients with Fabry cardiomyopathy. This study evaluated the incidence of significant arrhythmias in a series of patients with Fabry cardiomyopathy.

Hypothesis: Arrhythmias are important causes of morbidity and mortality in Fabry Cardiomyopathy.

Successful reduction of a high defibrillation threshold by a combined implantation of a subcutaneous array and azygos vein lead.

A 72-year-old man with nonischemic cardiomyopathy was referred because his implantable cardioverter defibrillator had failed to terminate spontaneous ventricular fibrillation (VF). Defibrillation threshold (DFT) testing confirmed that 830-V shocks failed to defibrillate VF despite optimization of the biphasic waveform and reversal of shock polarity. The placement of a new right ventricular lead and the addition of a subcutaneous array failed to defibrillate VF at 830 V.

Successful epicardial catheter ablation of a septal ventricular tachycardia after myocardial infarction.

A 55-year-old man underwent catheter ablation of ventricular tachycardia (VT) after anterior myocardial infarction. Although electrophysiological study suggested that the VT originated from the septum, biventricular endocardial irrigated radiofrequency ablation failed to interrupt the VT. Epicardial ablation at the site located halfway between the lesions in the right and left ventricles via a pericardial approach eliminated the VT, suggesting that the VT likely originated from the top of the septum.

Demonstration of a right ventricular substrate of ventricular tachycardia after myocardial infarction.

A 57-year-old man with prior anteroseptal myocardial infarction underwent catheter ablation of ventricular tachycardia (VT) exhibiting a left bundle branch block QRS morphology. After failed left ventricular ablation, catheter ablation from the right ventricle (RV) eliminated the VT. An RV voltage map demonstrated an area of low voltage around the successful ablation site that likely allowed for a VT substrate.

Idiopathic ventricular arrhythmias originating from the left ventricular summit: anatomic concepts relevant to ablation.

Background: The summit of the left ventricle (LV) is the most superior portion of the epicardial LV bounded by an arc from the left anterior descending coronary artery, superior to the first septal perforating branch to the left circumflex coronary artery. Ventricular arrhythmias (VAs) originating from this region may present challenges for catheter ablation.

Methods And Results: We studied 27 consecutive patients with VAs originating from the LV summit.

Focal ventricular arrhythmias originating from the left ventricle adjacent to the membranous septum.

Aims: We report the features of focal ventricular arrhythmias (VAs) arising from the left ventricle (LV) adjacent to the membranous septum.

Methods And Results: We studied eight patients (five men, 65 ± 10 years) with (n = 2) or without structural heart disease (n = 6) who had ventricular tachycardia (n = 4) or premature ventricular contractions (n = 4) originating from the LV septum underneath the aorta. Ventricular arrhythmias exhibited a focal activation pattern, left (n = 4) or right bundle branch block (n = 4), respectively, left superior (n = 4) or inferior axis QRS morphology (n = 4), negative QRS polarity in lead III and early or no precordial transition in all.

Electrocardiographic and electrophysiological characteristics in idiopathic ventricular arrhythmias originating from the papillary muscles in the left ventricle: relevance for catheter ablation.

Background: Idiopathic ventricular arrhythmias (VAs) can originate from the left ventricular papillary muscles (PAMs). This study investigated the electrophysiological characteristics of these VAs and their relevance for the results of catheter ablation.

Methods And Results: We studied 19 patients who underwent successful catheter ablation of idiopathic VAs originating from the anterior (n=7) and posterior PAMs (n=12).

Idiopathic ventricular tachycardia originating from the left ventricle near the His bundle.

A 62-year-old man with idiopathic ventricular tachycardia (VT) exhibiting left bundle branch block and left inferior axis QRS morphology with a Qr in lead III underwent electrophysiological testing. Successful ablation was achieved in the left ventricle (LV) at a site with an excellent pace map, adjacent to the His bundle electrogram recording site. At that site, the sequence of the ventricular electrogram and late potential recorded during sinus rhythm reversed during spontaneous premature ventricular contractions with the same QRS morphology as the VT.

Biventricular pacing improves cardiac function and prevents further left atrial remodeling in patients with symptomatic atrial fibrillation after atrioventricular node ablation.

Background: Randomized trials have demonstrated benefits of biventricular (BiV) pacing in patients with advanced heart failure, intraventricular conduction delay, and atrial fibrillation (AF) post-atrioventricular (AV) node ablation. The AV Node Ablation with CLS and CRT Pacing Therapies for Treatment of AF trial (AVAIL CLS/CRT) was designed to demonstrate superiority of BiV pacing in patients with AF after AV node ablation, to evaluate its effects on cardiac structure and function, and to investigate additional benefits of Closed Loop Stimulation (CLS) (BIOTRONIK, Berlin, Germany).

Methods: Patients with refractory AF underwent AV node ablation and were randomized (2:2:1) to BiV pacing with CLS, BiV pacing with accelerometer, or right ventricular (RV) pacing.

Successful catheter ablation of epicardial ventricular tachycardia worsened by cardiac resynchronization therapy.

Soon after an upgrade from a single-chamber implantable cardioverter-defibrillator (ICD) to cardiac resynchronization therapy (CRT) with an ICD, a 64-year-old man with non-ischaemic cardiomyopathy began to have increasingly frequent ICD shocks for slow ventricular tachycardia (VT). At electrophysiological study, no clinical VT was induced by endocardial right ventricular pacing, but was easily induced by epicardial left ventricular (LV) pacing via a subxiphoid pericardial approach. The VT was successfully ablated on the LV epicardial surface.

Limited response to cardiac resynchronization therapy in patients with concomitant right ventricular dysfunction.

Introduction: Patients with left ventricular dysfunction (LVD) and LV dyssynchrony may respond to cardiac resynchronization therapy (CRT). However, right ventricular dysfunction (RVD) is a predictor of decreased survival in patients with LVD, and its influence on clinical response to CRT is unknown. The purpose of this study was to examine the effect of RVD on the clinical response to CRT.