Positron emission tomography absolute stress myocardial blood flow for risk stratification in nonischemic cardiomyopathy.

Introduction: Sudden cardiac death is a substantial cause of mortality in patients with cardiomyopathy, but evidence supporting implantable cardioverter-defibrillator (ICD) implantation is less robust in nonischemic cardiomyopathy (NICM) than in ischemic cardiomyopathy. Improved risk stratification is needed. We assessed whether absolute quantification of stress myocardial blood flow (sMBF) measured by positron emission tomography (PET) predicts ventricular arrhythmias (VA) and/or death in patients with NICM.

Optimal method of measuring the T-peak to T-end interval for risk stratification in primary prevention.

Aims: Several published investigations demonstrated that a longer T-peak to T-end interval (Tpe) implies increased risk for ventricular tachyarrhythmia (VT/VF) and mortality. Tpe has been measured using diverse methods. We aimed to determine the optimal Tpe measurement method for screening purposes.

Natural History and Implantable Cardioverter-Defibrillator Implantation After Revascularization for Stable Coronary Artery Disease With Depressed Ejection Fraction.

Background: Following revascularization, most payors require 3 months of medical therapy, followed by left ventricular ejection fraction (LVEF) reassessment, before implantable cardioverter-defibrillator (ICD) implantation possibly contributing to incomplete follow-up and suboptimal utilization of ICD therapy. The natural history of these patients, and their fate regarding ICD implantation, is unknown.

Hypothesis: We hypothesized that a waiting period after revascularization for stable CAD results in missed opportunities to provide care with regard to ICD implantation.

Lifestyle modification in the prevention and treatment of atrial fibrillation.

Atrial fibrillation (AF) is the most common arrhythmia worldwide and has a significant impact on morbidity and mortality. Additionally, the incidence and prevalence of AF is expected to increase in the United States and worldwide over the next few decades. While the pathophysiology concerning the development of AF is not completely understood, multiple modifiable, as well as non-modifiable risk factors, for AF development have been discovered.

T-peak to T-end interval for prediction of ventricular tachyarrhythmia and mortality in a primary prevention population with systolic cardiomyopathy.

Background: The electrocardiographic T-wave peak to T-wave end interval (Tpe) correlates with dispersion of ventricular repolarization (DVR). Increased DVR increases propensity toward electrical reentry that can cause ventricular tachyarrhythmia. The baseline rate-corrected Tpe (Tpec) has been shown to predict ventricular tachyarrhythmia and death in multiple patient populations but not among cardiomyopathic patients undergoing insertion of an implantable cardioverter-defibrillator (ICD) for primary prevention.

Cardiometabolic risk factors and atrial fibrillation.

Atrial fibrillation (AF) is the most common arrhythmia worldwide; it is a significant risk factor for stroke and embolization, and has an impact on cardiac function. Despite its impact on morbidity and mortality, our understanding of the etiology and pathophysiology of this disease process is still incomplete. Over the past several decades, there has been evidence to suggest that AF has a significant correlation with metabolic syndrome (MetS).

First experience with a novel robotic remote catheter system: Amigo™ mapping trial.

Introduction: Amigo™ (Catheter Robotics, Inc., Mount Olive, NJ) remote catheter system (RCS) was designed to provide a simple and relatively inexpensive system for remote catheter manipulation. The purpose of this study was to evaluate the performance and safety of Amigo in mapping the right side of the heart.

Effect of rate-adaptive pacing on performance and physiological parameters during activities of daily living in the elderly: results from the CLEAR (Cylos Responds with Physiologic Rate Changes during Daily Activities) study.

Aims: For most elderly pacemaker patients, evaluation of rate-adaptive pacing using treadmill and bicycle tests is impractical and not representative of typical daily activities. This study was designed to compare the performance and physiological response of the closed-loop stimulation (CLS) rate-adaptive sensor to accelerometer (XL) and no rate sensor (DDD) during typical daily activity testing.

Methods And Results: Subjects recently implanted with a Cylos pacemaker completed timed activities of daily life testing, which included walking, sweeping, and standing from a seated position.

Relationships between the T-peak to T-end interval, ventricular tachyarrhythmia, and death in left ventricular systolic dysfunction.

Aims: The interval between the T-wave's peak and end (Tpe), an electrocardiographic (ECG) index of ventricular repolarization, has been proposed as an indicator of arrhythmic risk. We aimed to clarify the clinical usefulness of Tpe for risk stratification.

Methods And Results: We evaluated 327 patients with left ventricular ejection fraction (LVEF) ≤ 35% (75% male, LVEF 23 ± 7%).

Cardiac implantable electrical devices: bioethics and management issues near the end of life.

Cardiac implantable electrical devices (CIEDs) are extremely sophisticated modern devices that provide patients with many beneficial effects, including increased survival and enhanced quality of life. CIEDs, however, may complicate and unnecessarily prolong the process of dying from terminal illnesses. A rational plan for CIED deactivation near the end of life should therefore be carefully drawn up well in advance by the patient in concert with loved ones and treating physicians.

Long-term mortality in patients with pauses in ventricular electrical activity.

Background: The long-term significance of ventricular pauses of > or =3.0 seconds observed on Holter monitor is unclear, as previously conducted retrospective studies have been poorly controlled. We compared the prognosis of patients with pauses > or =3.

Relation between left ventricular geometry and transmural dispersion of repolarization.

Studies have shown an association between left ventricular (LV) geometry and complex ventricular ectopic activity. Increased transmural dispersion of repolarization (TDR), which correlates to the interval from the peak to the end of the T wave (Tpe) on the surface electrocardiogram, is linked to ventricular tachyarrhythmias. The relation between LV geometry and TDR is unknown.

Repeated dual external direct cardioversions using two simultaneous 360-J shocks for refractory atrial fibrillation are safe and effective.

Failure of cardioversion of atrial fibrillation (AF) to sinus rhythm (SR) by standard external direct current cardioversion (DCC) may be due to failure of delivery of enough defibrillating energy rather than to the true refractoriness of AF. Ninety-nine patients with persistent AF (76 male; age 63.7 +/- 0.

Pacing techniques in heart failure: current concepts and future outlook.

In addition to the well established benefits of traditional pacing methods, newer, left ventricular-based pacing techniques appear to induce significant hemodynamic improvements, benefit cardiac remodeling, improve functional capacity, and may decrease hospitalizations in appropriately selected patients with advanced systolic heart failure and intraventricular conduction defects. Encouraging results have been suggested from preliminary observational studies as well as from controlled clinical trials. Despite the generally positive outlook, much remains to be learned about multisite pacing techniques, appropriate site and patient selection, and long-term effectiveness.