UNLABELLED We have recently shown that exogenous nitric oxide (NO) elicits a positive chronotropic response by stimulating the hyperpolarization activated current, I(f). OBJECTIVE To examine whether L-arginine (L-Arg) can mimic the chronotropic effect of NO by enhancing its endogenous production. METHODS In spontaneously beating guinea pig atria we evaluated the heart rate (HR) response to ...

AIMS The aim of this study was to assess the association between resting heart rate (HR), chronotropic index (CI), and clinical outcomes in optimally treated chronic heart failure (HF) patients on β-blocker therapy. METHODS AND RESULTS We performed a sub-study in 1118 patients with HF and reduced ejection fraction (EF < 35%) included in the HF-ACTION trial. Patients in sinus rhythm who receiv...

INTRODUCTION Inhalation anesthetics have been shown to have electrical suppressant effects on excitable membranes such as the cardiac conduction system. Therefore, the anesthetized patient or laboratory animal may respond differently to cardiac drugs when compared with their conscious counterparts. The purpose of this study was to assess the effects of anesthesia with methoxyflurane (MF) on the...

It has been reported that some of H1 receptor antagonists have important effects on cardiovascular system. Terfenadine as a non-sedative H1 receptor antagonist has an arrhythmogenic activity. In this study we have shown the effects of four antihistamine drugs: terfenadine, loratadine, clemastine and diphenhydramine, on the rate and contractions of isolated rat atria. Terfenadine (1-10 µM) cause...

BACKGROUND Gender differences in the chronotropic effects of infused isoprenaline have previously been described. The aim of the present study was to investigate possible gender differences in hypokalaemic, chronotropic, and electrocardiographic effects of inhaled terbutaline. METHODS Twenty healthy volunteers (10 female) were recruited (mean age 24 years for women (F) and 22 years for men (M...

The use the aqueous decoction of Leonotis leonurus (L. leonurus) (Ll) R. Br. (Lamiaceae) in the treatment of hypertension (HPT) in traditional medicine is well documented. The effect of the aqueous extract of LI on the blood pressure (BP) and heart rate (HR) has been investigated in normotensive rats. The aim of this study was to investigate the effect of Ll aqueous extract on the in isolated p...

INTRODUCTION Erectile dysfunction (ED) and cardiovascular (CV) diseases share common risk factors and ED has been accepted as an early manifestation of CV disease. Exercise stress testing (EST) is used to evaluate CV functions in men with ED. Low exercise workload, a slower heart rate recovery (HRR) after exercise, and inability to increase heart rate during EST (chronotropic incompetence) are ...

1. In response to graded infusions of isoprenaline, adult spontaneously hypertensive rats (20-24 weeks old) showed diminished responses of left ventricular contractile indices, diminished chronotropic responses and impairment of left ventricular relaxation rate as compared with matched Kyoto-Wistar rats. 2. These findings suggest reduced capacity to increase contractility in response to stress.

OBJECTIVES An impaired heart rate response during exercise (chronotropic incompetence) and an impaired heart rate recovery (HRR) after exercise are predictors of cardiovascular risk and mortality. Cystatin C is a novel marker for cardiovascular disease. We aimed to investigate exercise electrocardiographic responses in patients with metabolic syndrome who were without overt diabetes mellitus, i...