QRS duration on electrocardiography and cardiovascular mortality (from the National Health and Nutrition Examination Survey-III).

The relation of bundle branch block (BBB) with adverse outcome is controversial. We hypothesized that increased QRS duration is an independent predictor of cardiovascular (CV) mortality in a cross-sectional US population. This is a retrospective cohort study on prospectively collected data to assess the relationship between QRS duration on routine ECG and CV mortality.

Comparison of rate versus rhythm control in patients with atrial fibrillation and a pacemaker.

The effect of rate versus rhythm control in patients with atrial fibrillation who have undergone previous pacemaker (PM) implantation is unknown. We evaluated the mortality in patients with atrial fibrillation and a PM randomized to rate or rhythm control treatment strategies. The Atrial Fibrillation Follow-up Investigation of Rhythm Management data set was stratified by the presence (n = 250) or absence (n = 3,810) of a PM at randomization into the rate or rhythm control arm.