Circadian and gender effects on repolarization in healthy adults: a study using harmonic regression analysis.

Background: Sudden cardiac death and myocardial infarction have a circadian variation with a peak incidence in the early morning hours. Increased dispersion of repolarization facilitates the development of conduction delay necessary to induce sustained arrhythmia. Both QT-dispersion and T-wave peak to T-wave end (TpTe) have been proposed as markers of dispersion of myocardial repolarization.

Patients with recently diagnosed nonischemic cardiomyopathy benefit from implantable cardioverter-defibrillators.

Objectives: This study sought to determine whether the time from diagnosis to randomization was related to outcome in a clinical trial of implantable cardioverter-defibrillator (ICD) insertion in nonischemic cardiomyopathy.

Background: Whether the duration of nonischemic cardiomyopathy is related to arrhythmic risk and the possible benefit of ICD insertion is unknown.

Methods: The Defibrillators in Nonischemic Cardiomyopathy Treatment Evaluation (DEFINITE) trial randomized 458 patients with nonischemic dilated cardiomyopathy and a left ventricular ejection fraction <36% to receive standard medical therapy with or without an ICD.

Beta blocker therapy after acute myocardial infarction in patients with heart failure and systolic dysfunction.

The benefit of beta blockade has been well established in acute myocardial infarction for several decades, and its benefit in chronic heart failure has been proven since the early 1990's. Several large retrospective analyses suggested the benefit of beta blockers in post-MI systolic dysfunction. Only recently has the benefit of beta blockers been proven in addition to ACE inhibitors, antiplatelet agents, and reperfusion therapy.

Nesiritide does not improve renal function in patients with chronic heart failure and worsening serum creatinine.

Background: Nesiritide (synthetic human brain natriuretic peptide) is approved for the treatment of symptomatic heart failure. However, studies of brain natriuretic peptide in patients with heart failure have come to conflicting conclusions about effects on glomerular filtration rate (GFR), effective renal plasma flow, natriuresis, and diuresis.

Methods And Results: To identify a population at high risk of renal dysfunction with conventional treatment, we selected patients with a creatinine level increased from baseline (within 6 months).