Reduced diurnal variation of heart rate is associated with increased plasma B-type natriuretic peptide level in patients with atrial fibrillation.

Background: The plasma B-type natriuretic peptide (BNP) level has been shown to be increased in patients with chronic atrial fibrillation (AF) independent of left ventricular ejection fraction (LVEF). The purpose of this study is to evaluate the relationship between the plasma BNP level and heart rate variation in patients with AF.

Hypothesis: The plasma BNP level is associated with heart rate variation in patients with AF.

Intermittent arm ischemia induces vasodilatation of the contralateral upper limb.

Intermittent arm ischemia before percutaneous coronary intervention induces remote ischemic preconditioning (RIPC) and attenuates myocardial injury in patients with myocardial infarction. Several studies have shown that intermittent arm ischemia increases coronary flow and is related to autonomic nerve system. The aim of this study was to determine whether intermittent arm ischemia induces vasodilatation of other arteries and to assess changes in the autonomic nerve system during intermittent arm ischemia in humans.

Abnormal transmural repolarization process in patients with Brugada syndrome.

Background: Repolarization abnormality, especially during bradycardia, might be critical for initiation of ventricular fibrillation (VF) in patients with Brugada syndrome (BrS), but the contribution of the rate-dependent repolarization dynamics to the occurrence of VF is still unknown.

Objective: The aim of our study was to determine the differences in rate-dependent repolarization dynamics between BrS with and without spontaneous VF and between BrS with and without SCN5A mutation.

Methods: The subjects were 37 BrS patients with VF (VF(+) group: 10 male subjects) and without VF (VF(-) group: 27 male subjects) and 20 control subjects.

Nicorandil reduces the incidence of minor cardiac marker elevation after coronary stenting.

Background: Minor cardiac marker elevation after percutaneous coronary intervention has long-term prognostic significance. We examined whether nicorandil, a nicotinamide-nitrate ester, reduces the incidence of minor cardiac marker elevation after coronary stenting.

Methods: Patients (n=192) undergoing coronary stenting were randomly assigned to receive nicorandil (nicorandil group, n=91) or vehicle (control group, n=101).

Intense response of heart rate with pronounced suppression of high-frequency power of heart rate variability to early morning exercise with high-intensity load.

Autonomic nerve activity shows circadian variation. Therefore, we put forward the hypothesis that the responses of heart rate (HR) and high-frequency (HF) power of HR variability to exercise would be different between early morning and daytime exercise. We performed ergometer constant load exercise tests [50 watts (low), 100 watts (high load)] in the early morning and during the day in 6 healthy volunteers.