Natural History of Implantable Cardioverter-Defibrillator Implanted at or after the Age of 70 years in a Veteran Population: A Single Center Study.

Background: The median age of patients in major Implantable Cardioverter-defibrillator (ICD)trials (MUSTT, MADIT-I, MADIT-II, and SCD-HeFT) was 63-67 years; with only 11% ≥70 years. There is little follow-up data on patients over 70 years of age who received an ICD for primary/secondary prevention of sudden cardiac death, particularly for veterans.

Objective: The aim of this study was to study the natural history of ICD implantation for veterans over 70 years of age.

Circadian variability patterns predict and guide premature ventricular contraction ablation procedural inducibility and outcomes.

Background: Infrequent intraprocedural premature ventricular complexes (PVCs) may impede radiofrequency catheter ablation (RFA) outcome, and pharmacologic induction is unpredictable.

Objective: The purpose of this study was to determine whether PVC circadian variation could help predict drug response.

Methods: Consecutive patients referred for RFA with detailed Holter monitoring and frequent monomorphic PVCs were included.

Electrocardiographic Localization of Ventricular Tachycardia in Patients with Structural Heart Disease.

The 12-lead electrocardiogram (ECG) during ventricular tachycardia (VT) in patients with structural heart disease contains information that helps to narrow the electrophysiologist's search for target sites for ablation. Although replacement of myocardium by scar might be expected to produce variability in the spread of activation during VT, nonetheless reasonably consistent ECG patterns exist that can regionalize exit sites from VT circuits in up to 75% of cases. Most experience with this comes from patients with prior myocardial infarction, but a growing body of data exists concerning patients with nonischemic cardiomyopathies.

Relation of short-term heart rate variability to incident heart failure (from the Multi-Ethnic Study of Atherosclerosis).

Whether autonomic dysfunction predates the development of symptomatic heart failure (HF) or is simply a consequence of severe HF is unknown. We hypothesized that reduced heart rate variability (a marker of abnormal autonomic function) at baseline is associated with incident HF in subjects free of clinically recognized cardiovascular disease. In the Multi-Ethnic Study of Atherosclerosis (MESA), a population-based study of subclinical cardiovascular disease in adults aged 45 to 84 years, we measured the heart rate variability using a standard 30-second, 12-lead electrocardiogram to measure the standard deviation of normal-to-normal intervals (SDNN) and the root mean square of successive differences in RR intervals (RMSSD).