Vigorous Exercise in Patients With Congenital Long QT Syndrome: Results of the Prospective, Observational, Multinational LIVE-LQTS Study.

Background: Whether vigorous exercise increases risk of ventricular arrhythmias for individuals diagnosed and treated for congenital long QT syndrome (LQTS) remains unknown.

Methods: The National Institutes of Health-funded LIVE-LQTS study (Lifestyle and Exercise in the Long QT Syndrome) prospectively enrolled individuals 8 to 60 years of age with phenotypic and/or genotypic LQTS from 37 sites in 5 countries from May 2015 to February 2019. Participants (or parents) answered physical activity and clinical events surveys every 6 months for 3 years with follow-up completed in February 2022.

Mast Cell Activation Disorder and Postural Orthostatic Tachycardia Syndrome: A Clinical Association.

Background Recently there has been increased interest in a possible association between mast cell activation (MCA) disorder and postural orthostatic tachycardia syndrome (POTS). This study examined the frequency with which symptoms and laboratory findings suggesting MCA disorder occurred in patients diagnosed with POTS. Methods and Results Data were obtained from patients in whom symptoms and orthostatic testing were consistent with a POTS diagnosis.

Safety of Sports for Young Patients With Implantable Cardioverter-Defibrillators: Long-Term Results of the Multinational ICD Sports Registry.

Background: Despite safety concerns, many young patients with implantable cardioverter-defibrillators (ICDs) participate in sports. We undertook a prospective, multinational registry to determine the incidence of serious adverse events because of sports participation. The primary end points were death or resuscitated arrest during sports or injury during sports because of arrhythmia or shock.

Mortality reduction in relation to implantable cardioverter defibrillator programming in the Multicenter Automatic Defibrillator Implantation Trial-Reduce Inappropriate Therapy (MADIT-RIT).

Background: The benefit of novel implantable cardioverter defibrillator (ICD) programming in reducing inappropriate ICD therapy and mortality was demonstrated in Multicenter Automatic Defibrillator Implantation Trial-Reduce Inappropriate Therapy (MADIT-RIT). However, the cause of mortality reduction remains incompletely evaluated. We aimed to identify factors associated with mortality, with focus on ICD therapy and programming in the MADIT-RIT population.

Survival with cardiac-resynchronization therapy in mild heart failure.

Background: The Multicenter Automatic Defibrillator Implantation Trial with Cardiac Resynchronization Therapy (MADIT-CRT) showed that early intervention with cardiac-resynchronization therapy with a defibrillator (CRT-D) in patients with an electrocardiographic pattern showing left bundle-branch block was associated with a significant reduction in heart-failure events over a median follow-up of 2.4 years, as compared with defibrillator therapy alone.

Methods: We evaluated the effect of CRT-D on long-term survival in the MADIT-CRT population.

Amiodarone reduces the amount of ablation during catheter ablation for persistent atrial fibrillation.

Aims: The step-wise approach to catheter ablation for persistent atrial fibrillation (AF) requires considerable substrate modification targeting at complex fractionated atrial electrograms (CFAEs) in addition to pulmonary vein (PV) isolation. An alternative strategy that minimizes the amount of ablation would be desirable. The aim of this study was to investigate whether the use of pre-procedural amiodarone affects: (i) the amount of ablation required to achieve procedural success, and (ii) long-term outcomes.

History of syncope in the cardiac literature.

The rich cardiology literature of the past 100 years in which the most important forms of syncope are described - including vasodepressor syncope, postural orthostatic hypotension, and Morgagni-Stokes-Adams syncope - is fascinating. These conditions were of interest to some of our most astute clinicians who were also excellent writers. We thus have available for review the remarkable description of patients with these entities written by clinicians such as Soma Weiss, Sir Thomas Lewis, Laurence Ellis, David Sherf, Milton Shy, and Glenn Drager.

Reduction in inappropriate therapy and mortality through ICD programming.

Background: The implantable cardioverter-defibrillator (ICD) is highly effective in reducing mortality among patients at risk for fatal arrhythmias, but inappropriate ICD activations are frequent, with potential adverse effects.

Methods: We randomly assigned 1500 patients with a primary-prevention indication to receive an ICD with one of three programming configurations. The primary objective was to determine whether programmed high-rate therapy (with a 2.

Improved outcome with preventive cardiac resynchronization therapy in the elderly: a MADIT-CRT substudy.

Background: Elderly patients comprise a large portion of patients with heart failure (HF). Limited data exist on the effectiveness of cardiac resynchronization therapy with defibrillator (CRT-D) in patients with mild HF symptoms in this population.

Methods And Results: The benefit of CRT-D compared with ICD-only therapy in reducing HF or death was assessed by age categories (prespecified as <60 [n = 548], 60-74 [n = 941], and ≥75 [n = 331] years) among 1,820 patients in MADIT-CRT.

The use of balloon atrial septostomy to facilitate difficult transseptal access in patients undergoing catheter ablation for atrial fibrillation.

Introduction: With the increasing number of patients undergoing repeat catheter ablation procedures for atrial fibrillation, it is not uncommon to encounter a fibrotic interatrial septum that resists the conventional manual advancement of the transseptal sheath. Forceful advancement of the transseptal apparatus can reduce fine control and potentially lead to a higher rate of perforation.

Case: We report a case where adjunctive balloon atrial septostomy was used to facilitate transseptal access in a patient with fibrotic interatrial septum.

Comparison of the point-by-point versus catheter dragging technique for curative radiofrequency ablation of atrial fibrillation.

Background: The relationship between the applied techniques and clinical outcomes after radiofrequency (RF) ablation of atrial fibrillation (AF) remains unclear. We compared the results of ablation by RF delivered via a point-by-point versus catheter dragging technique for the treatment of AF.

Methods: This study included 66 patients with drug-refractory AF who underwent circumferential pulmonary vein (PV) ablation.