Performance of an automatic arrhythmia classification algorithm: comparison to the ALTITUDE electrophysiologist panel adjudications.

Introduction: Adjudication of thousands of implantable cardioverter defibrillator (ICD)-treated arrhythmia episodes is labor intensive and, as a result, is most often left undone. The objective of this study was to evaluate an automatic classification algorithm for adjudication of ICD-treated arrhythmia episodes.

Methods: The algorithm uses a machine learning algorithm and was developed using 776 arrhythmia episodes.

Impact of shock energy and ventricular rhythm on the success of first shock therapy: the ALTITUDE first shock study.

Background: The efficacy of shock in converting different ventricular tachyarrhythmias has not been well characterized in a large natural-practice setting.

Objective: To determine shock success rate by energy and ventricular rhythm in a large cohort of patients with implantable cardioverter-defibrillators.

Methods: Two thousand patients with 5279 shock episodes were randomly sampled for analysis from the LATITUDE remote monitoring system.

Noise, artifact, and oversensing related inappropriate ICD shock evaluation: ALTITUDE noise study.

Background: Approximately 12-21% of implantable cardioverter defibrillator (ICD) patients receive inappropriate shocks. We sought to determine the incidence and causes of noise/artifact and oversensing (NAO) resulting in ICD shocks.

Methods: A random sample of 2,000 patients who received ICD and cardiac resynchronization therapy defibrillator shocks and were followed by a remote monitoring system was included.

Impact of relaxation training on patient-perceived measures of anxiety, pain, and outcomes after interventional electrophysiology procedures.

Background: Electrophysiology procedures vary in invasiveness, duration, and anesthesia utilized. While complications are low and efficacy high, cases are elective and patient experiences related to anxiety, pain, and perceived outcomes are not well studied. We sought to determine if a 30-minute audio compact disc (CD) that teaches relaxation techniques and wellness perception prior to an elective procedure impacts validated measures of anxiety, pain, and procedural outcomes.

Implantable cardioverter defibrillator electrogram adjudication for device registries: methodology and observations from ALTITUDE.

Background: The increasing use of remote monitoring with the associated large retrievable databases provides a unique opportunity to analyze observations on implantable cardioverter-defibrillator (ICD) therapies. Adjudication of a large number of stored ICD electrograms (EGMs) presents a unique challenge. The ALTITUDE study group was designed to use the LATITUDE remote monitoring system to evaluate ICD patient outcomes across the United States.

Ventricular tachycardia in the era of ventricular assist devices.

Sustained ventricular tachycardia (VT) in patients with advanced cardiomyopathy is a potentially life-threatening arrhythmia. Newer treatment strategies have evolved that combine the use of catheter ablation to target the substrate for VT and ventricular assist devices (VADs) to hemodynamically support the failing ventricle. This editorial is targeted to the practicing clinician caring for these difficult patients.

Novel use of a vascular plug to anchor an azygous vein ICD lead.

We describe the case of a young patient with severe hypertrophic cardiomyopathy and marginal defibrillation thresholds (DFTs) at implant of a standard transvenous implantable cardioverter-defibrillator (ICD) system. The patient subsequently experienced multiple failed ICD shocks during a prolonged episode of spontaneous ventricular tachycardia/fibrillation. Placement of a second single-coil shocking lead in the azygous vein resulted in acceptable DFTs, but the new lead migrated superiorly within hours of the procedure.

Supraventricular tachycardia after orthotopic cardiac transplantation.

Objectives: The purpose of this study was to define the incidence, mechanisms, and management, including catheter ablation, of supraventricular tachycardia (SVT) in a large series of patients after orthotopic heart transplantation (OHT).

Background: Supraventricular arrhythmias are frequently encountered after OHT, but their characteristics in this population have not been well established.

Methods: We analyzed the incidence, clinical course, and management of SVTs in a cohort of 729 adult patients who underwent OHT.

Biventricular pacing and defibrillator use in chronic heart failure.

Since the 1970s when the implantable cardioverter defibrillator (ICD) was developed, multiple clinical trials have documented survival benefits in certain high-risk subsets of heart failure patients. Over the past decade, cardiac resynchronization therapy (CRT) emerged as an important therapy in carefully selected patients with ongoing symptoms despite optimized pharmacological therapy. ICDs should be considered first-line therapy for survivors of life-threatening ventricular arrhythmic events.

Cardiac resynchronization therapy response is associated with shorter duration of atrial fibrillation.

Background: Atrial fibrillation (AF) is commonly associated with heart failure. The benefit of cardiac resynchronization therapy (CRT) on atrial remodeling has been demonstrated. However, biventricular pacing did not reduce the global incidence of AF.

Left ventricular apical wall motion abnormality is associated with lack of response to cardiac resynchronization therapy in patients with ischemic cardiomyopathy.

Background: Many patients with appropriate indications fail to respond to cardiac resynchronization therapy (CRT).

Objective: The purpose of our study was to determine the relationship between CRT response and preimplantation apical wall motion abnormality.

Methods: We analyzed data from 83 patients with ischemic cardiomyopathy who underwent CRT.

Changes and predictive value of dispersion of repolarization parameters for appropriate therapy in patients with biventricular implantable cardioverter-defibrillators.

Background: The impact of cardiac resynchronization therapy (CRT) on dispersion of repolarization is controversial. The benefit of CRT on sudden cardiac death has been demonstrated only after 3 years follow-up.

Objective: The purpose of this study was to explore the immediate effect of CRT on dispersion of repolarization and to define the value of dispersion of repolarization parameters as predictors of appropriate implantable cardioverter-defibrillator (ICD) therapy.

Usefulness of preimplantation B-type natriuretic peptide level for predicting response to cardiac resynchronization therapy.

Nearly 1/3 of patients with heart failure (HF) fail to respond to cardiac resynchronization therapy (CRT). The purpose of this study was to evaluate the value of preimplantation brain natriuretic peptide (BNP) in predicting the clinical response to CRT. We retrospectively analyzed 164 patients who underwent CRT.

A novel method for preventing phrenic nerve injury during catheter ablation.

Epicardial catheter ablation is increasingly important in the treatment of ventricular arrhythmias. Collateral damage to adjacent structures like the phrenic nerve is an important concern with epicardial ablation. This report describes the use of a novel method to prevent phrenic nerve injury during epicardial ablation of ventricular tachycardia.

Percutaneous intrapericardial echocardiography during catheter ablation: a feasibility study.

Background: Percutaneous pericardial access, epicardial mapping, and ablation have been used successfully for catheter ablation procedures.

Objectives: The purpose of this study was to evaluate the safety and feasibility of closed-chest direct epicardial ultrasound imaging for aiding cardiac catheter ablation procedures.

Methods: An intracardiac ultrasound catheter was used for closed-chest epicardial imaging of the heart in 10 patients undergoing percutaneous epicardial access for catheter ablation.

Alterations in ion channel physiology in diabetic cardiomyopathy.

Diabetes mellitus is one of the most common chronic illnesses worldwide. This article focuses on a subgroup of diabetic patients with a specific cardiac complication of this disease--diabetic cardiomyopathy. This article initially gives some general background on diabetic cardiomyopathy and ion channels.

Catheter ablation of right ventricular outflow tract tachycardia: value of defining coronary anatomy.

Introduction: Thermal damage to coronary arteries during catheter ablation has been previously reported. Coronary artery damage during LV outflow tract ventricular tachycardia is well recognized. However, the relationship of the coronary arteries to the RV outflow tract during catheter ablation has not been delineated.

Left ventricular lead stabilization utilizing a coronary stent.

Cardiac resynchronization therapy has been recently demonstrated to have a mortality and morbidity benefit in heart failure (HF) patients with cardiac dyssynchrony. Currently, the most widely used method of left ventricular (LV) lead placement involves transvenous placement of leads via the coronary sinus (CS) and into a tributary branch. Lead dislodgement is a common cause for reoperation, and continues to be a common problem despite advances in equipment and operator techniques.

Implantable cardioverter-defibrillator therapy in clinical practice.

Pharmacologic treatment of heart failure has led to dramatic improvements in survival and quality of life. Nonetheless, heart failure often progresses despite treatment with diuretics, angiotensin-converting enzyme inhibitors, beta-adrenergic blockers, aldosterone antagonists, and digoxin. Further, despite a steady decline in the risk of death from pump failure, many patients remain at high risk for sudden cardiac death.

Value of high-density endocardial and epicardial mapping for catheter ablation of hemodynamically unstable ventricular tachycardia.

Background: Percutaneous epicardial mapping has been used for ablation of recurrent ventricular tachycardia (VT).

Objectives: The purpose of this study was to use a combined epicardial and endocardial mapping strategy to delineate the myocardial substrate for recurrent VT in both ischemic (n = 12) and nonischemic cardiomyopathy (n = 8), and to define the role of epicardial ablation.

Methods: Electroanatomic mapping was performed in 20 patients.

Impedance monitoring during catheter ablation of atrial fibrillation.

Background: Delivery of radiofrequency energy in proximity of a pulmonary vein can cause vein stenosis. A sudden decrease in impedance as the catheter is moved from the vein into the left atrium (LA) has been used to define the pulmonary vein-LA transition during ablation procedures.

Objectives: The purpose of this study was to define the variables affecting impedance measurement.