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Patients with diabetes mellitus, prior myocardial infarction, older age, and a relatively preserved left ventricular ejection fraction remain at risk for sudden cardiac death that is potentially amenable by the subcutaneous implantable cardioverter defibrillator with a good risk-benefit profile. The launched MADIT S-ICD study is designed to test the hypothesis that post-myocardial infarction diabetes patients with relatively preserved ejection fraction of 36%-50% will have a survival benefit from a subcutaneous implantable cardioverter defibrillator., (Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.)

Background: Pulmonary vein antrum isolation (PVI) as a treatment of paroxysmal atrial fibrillation (AF) is associated with a high rate of success; however, outcomes for treating persistent and long-standing persistent AF with PVI alone are substantially lower and often require multiple procedures to maintain long-term freedom from atrial arrhythmias. Foci and/or substrate outside the pulmonary veins, particularly in the left atrial appendage (LAA), has been identified as a key mechanism in the maintenance of persistent AF and long-standing persistent AF., Objective: The goals of the study are to evaluate the safety and effectiveness of the LARIAT System to percutaneously isolate and ligate the LAA and to determine if LAA ligation as adjunctive therapy to PVI improves maintenance of sinus rhythm in patients with persistent and long-standing persistent AF., Study Design: The trial is a prospective, multicenter, randomized controlled study. The trial design incorporates a Bayesian adaptive design that will randomize a maximum of 600 patients with persistent or long-standing persistent AF to LAA ligation and PVI vs PVI alone in a 2:1 randomization. The primary end points include 30-day safety of the LARIAT procedure and freedom from documented AF, atrial flutter, or atrial tachycardia of more than 30 seconds at 12 months after the PVI off antiarrhythmic drugs. Key secondary outcomes include a composite of cardiovascular death and stroke, as well as quality of life., Conclusion: The aMAZE trial will determine if LAA ligation as adjunctive therapy to PVI increases the efficacy of maintaining sinus rhythm in patients with persistent and long-standing persistent AF., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Atrial fibrillation (AF) is a major public health problem in the United States that is associated with increased mortality and morbidity. Of the therapeutic modalities available to treat AF, the use of percutaneous catheter ablation of AF is expanding rapidly. Randomized clinical trials examining the efficacy and safety of AF ablation are currently underway; however, such trials can only partially determine the safety and durability of the effect of the procedure in routine clinical practice, in more complex patients, and over a broader range of techniques and operator experience. These limitations of randomized trials of AF ablation, particularly with regard to safety issues, could be addressed using a synergistically structured national registry, which is the intention of the SAFARI. To facilitate discussions about objectives, challenges, and steps for such a registry, the Cardiac Safety Research Consortium and the Duke Clinical Research Institute, Durham, NC, in collaboration with the US Food and Drug Administration, the American College of Cardiology, and the Heart Rhythm Society, organized a Think Tank meeting of experts in the field. Other participants included the National Heart, Lung and Blood Institute, the Centers for Medicare and Medicaid Services, the Agency for Healthcare Research and Quality, the Society of Thoracic Surgeons, the AdvaMed AF working group, and additional industry representatives. The meeting took place on April 27 to 28, 2009, at the US Food and Drug Administration headquarters in Silver Spring, MD. This article summarizes the issues and directions presented and discussed at the meeting., (Copyright 2010 Mosby, Inc. All rights reserved.)

Background: Prior reports describing magnetic resonance (MR) imaging abnormalities in arrhythmogenic right ventricular dysplasia (ARVD/C) were limited by nonuniform inclusion criteria. The aim of our study was to define the prevalence, sensitivity, and specificity of quantitative MR imaging findings in the probands of multidisciplinary study of right ventricular dysplasia., Methods: Individuals with ventricular arrhythmias of left bundle-branch block morphology meeting the Task Force criteria for ARVD/C underwent MR imaging. The MR images were compared with 10 patients with idiopathic ventricular tachycardia (VT) and 25 controls. Of the 42 study probands, 40 met the Task Force criteria exclusive of MR imaging findings. All MR images were interpreted in a blinded fashion., Results: Right ventricle fat infiltration was reported in 24 (60%) probands and none of the patients with idiopathic VT or controls. Six patients (15%) had fat infiltration of the left ventricle. Right ventricle regional dysfunction was observed in 32 probands (80%) and none of the patients with idiopathic VT or controls. Qualitative RV function was abnormal in 26 probands (60%); however, quantitative RV ejection fraction was abnormal in 85% (24/28) of the probands. An RV ejection fraction <50% had a sensitivity of 73% and a specificity of 95% in diagnosis of ARVD/C., Conclusions: Fat infiltration is seldom the only MR imaging abnormality and is less sensitive for ARVD/C diagnosis compared with RV regional dysfunction. Qualitative estimates of RV function may underestimate the prevalence of RV dysfunction in ARVD/C. Quantitative evaluation of RV by MR imaging may have a high sensitivity and specificity for ARVD/C diagnosis.

Background: More than 200,000 permanent pacemakers will be implanted in the United States in 2000 at a cost of more than $2 billion. Sick sinus syndrome (SSS) will likely account for approximately half of all cases necessitating implantation. Pacemaker technology permits the selection of ventricular (single-chamber) or dual-chamber devices. However, clinical and outcomes data are inadequate to support a clear recommendation that one or the other type of device be used., Methods: The Mode Selection Trial (MOST) is a single-blind study supported by the National Heart, Lung, and Blood Institute designed to enroll 2000 patients with SSS. All patients will receive a DDDR pacemaker programmed to VVIR or DDDR before implantation. The average time of follow-up will be 3 years. MOST has a >90% power to detect a 25% reduction in the primary end point-nonfatal stroke or total (all cause) mortality-in the DDDR-treated group. Secondary end points will include health-related quality of life and cost effectiveness, atrial fibrillation, and development of pacemaker syndrome. Prespecified subgroups for analysis will include women and the elderly. Enrollment was completed in October 1999, with a total of 2010 patients., Results: The median age of the first 1000 enrolled patients is 74 years, with 25% of patients 80 years or older. Women comprise 49%, and 17% are nonwhite, predominantly black (13%). Before pacemaker implantation, 22% of patients reported a history of congestive heart failure, 11% coronary angioplasty, and 25% coronary bypass surgery. Supraventricular tachycardia including atrial fibrillation was present in 53% of patients. A prior stroke was reported by 12%. Antiarrhythmic therapy was in use in 18% of patients., Conclusions: MOST will fill the clinical need for carefully designed prospective studies to define the benefits of dual-chamber versus single-chamber ventricular pacing in patients with SSS. The MOST population is typical of the overall pacemaker population in the United States. Thus the final results of MOST should be clinically generalizable.

Over a 2-year period, 110 patients underwent attempted implantation of an automatic cardioverter-defibrillator using the nonthoracotomy lead system. Indications included sustained monomorphic ventricular (n = 62), nonsustained with poor ventricular function (n = 7), ventricular fibrillation (n = 21), ventricular tachycardia/fibrillation (n = 18), and familial long QT syndrome (n = 2). There were 90 male and 20 female patients. Mean age was 57 +/- 15 years. Sixty percent had previous coronary bypass or valve operations, or both. Mean left ventricular ejection fraction was 30% +/- 14%, cardiac index was 2.4 +/- 0.9 L/m2, and systolic pulmonary artery pressure was 41 +/- 14 mm Hg. Under general anesthesia, the nonthoracotomy lead was introduced through the left subclavian vein. The subcutaneous patch and generator were placed posteriorly on the serratus muscle and left upper quadrant, respectively. The length of the procedure was 116 +/- 44 minutes and the mean number of defibrillation shocks for a successful implant was 8 +/- 4. Eighty-five patients (77%) had successful implantations. Failures were due to high defibrillation threshold (n = 23) and inability to place a right ventricular lead (n = 2). Predictors of failure included preoperative antiarrhythmic drugs and cardiac index of 1.8 +/- 4 L/m2 or less (p = 0.004). Three patients (2.7%) died after the operation of heart failure (n = 2) and chronic heart transplant rejection (n = 1). Complications included lead migration or dislodgment (n = 8), infection (n = 1), and hematoma (n = 3). In summary, the nonthoracotomy lead system may provide an alternative in patients undergoing cardioverter-defibrillator implantation.

Approximately 30% of deaths among patients with IDCM are sudden. Although ventricular tachyarrhythmias are responsible for many of these deaths, bradyarrhythmias may also play a significant role. Patients with a previous history of sustained ventricular arrhythmias are at high risk for sudden death. In patients without prior symptomatic ventricular arrhythmias a history of unexplained syncope, severely impaired right ventricular hemodynamics, frequent spontaneous ventricular ectopy or NSVT, and inducible SMVT may help identify those at greatest risk of dying suddenly. With the exception of angiotensin-converting enzyme inhibitor therapy, attempts at pharmacologic prevention of sudden death have had limited efficacy. The implantable defibrillator offers promising results in survivors of previous sustained ventricular arrhythmias; its prophylactic use in other high-risk subgroups is the subject of active investigation.

The relationship between inducible ventricular tachycardia in the convalescent phase of myocardial infarction and subsequent spontaneous ventricular fibrillation is uncertain. Thirty conscious instrumented dogs underwent programmed ventricular stimulation 5 days after anterior infarction; 15 had inducible ventricular tachycardia and 15 were noninducible. Following programmed ventricular stimulation, the application of a 150 uA current to the intima of the proximal circumflex artery initiated intimal damage, thrombosis, and acute ischemia of the posterolateral wall. After 20 minutes of ischemia, 73% inducible and 15% noninducible animals developed ventricular fibrillation (p less than 0.005) without previous hypotension. At 24 hours, 7% inducible and 85% noninducible animals survived (p less than 0.001). Anterior infarct size (percentage of left ventricular mass) was much larger in inducible (24.7 +/- 1.7%) than in noninducible (5.3 +/- 1.1%) (p less than 0.001) animals. Inducible ventricular tachycardia following infarction was highly predictive of spontaneous ventricular fibrillation during a later ischemic episode in this model. The mass of previously injured myocardium was a critical determinant of both.