About 10 distinct potassium channels in the heart are involved in shaping the action potential. Some of the K+ channels are primarily responsible for early repolarization, whereas others drive late repolarization and still others are open throughout the cardiac cycle. Three main K+ channels drive the late repolarization of the ventricle with some redundancy, and in atria this repolarization res...

BACKGROUND More accurate and reliable stroke risk prediction tools are needed to optimize anticoagulation decision making in patients with atrial fibrillation (AF). We developed a new AF stroke prediction model using the original Anticoagulation and Risk Factors in Atrial Fibrillation (ATRIA) AF cohort and externally validated the score in a separate, contemporary, community-based inception AF ...

BACKGROUND An imbalance of sympathetic and parasympathetic drive to the heart is an important risk factor for cardiac death in patients with coronary heart disease, diabetes, and renal insufficiency. The amount of neurotransmitter released from peripheral autonomic nerves is modulated by presynaptic receptor systems. In analogy to alpha-autoreceptors on sympathetic nerves, muscarinic autorecept...

Dilation and hypertrophy of the atria occur in patients with valvular heart disease especially in mitral regurgitation, mitral stenosis or tricuspid abnormalities. In sub-saharan Africa, rheumatic fever is still the leading cause of valvular heart disease. We report a case of an unusual giant right atrium in context of rheumatic stenosis and severe tricuspid regurgitation in a 58-year-old woman.

Small-conductance Ca2+-activated K+ channels (SK channels, KCa channels) have been reported in excitable cells, where they aid in integrating changes in intracellular Ca2+ with membrane potential. We recently reported for the first time the functional existence of SK2 (KCa2.2) channels in human and mouse cardiac myocytes. Here, we report cloning of SK1 (KCa2.1) and SK3 (KCa2.3) channels from mo...

The hyperpolarization-activated cyclic nucleotide-gated (HCN) channels are expressed in pacemaker cells very early during cardiogenesis. This work aimed at determining to what extent these channels are implicated in the electromechanical disturbances induced by a transient oxygen lack which may occur in utero. Spontaneously beating hearts or isolated ventricles and outflow tracts dissected from...

In this study, semiquantitative reverse transcription-PCR analysis showed that estrogen receptor alpha (ERalpha) and beta (ERbeta) mRNAs are developmentally regulated in the rat heart. We found that ERalpha mRNA was low in all heart chambers of 4-day-old rats, but was elevated in the atria (6- to 18-fold) and ventricles (3- to 4-fold) of adult rats. Western blotting analysis confirmed that thes...

AIMS Several cardiac resident progenitor cell types have been reported for the adult mammalian heart. Here we characterize their frequencies and distribution pattern in non-ischaemic human myocardial tissue and after ischaemic events. METHODS AND RESULTS We obtained 55 biopsy samples from human atria and ventricles and used immunohistological analysis to investigate two cardiac cell types, ch...

Imidazoline receptors are divided into I(1) and I(2) subtypes. I(1)-imidazoline receptors are distributed in the heart and are upregulated during hypertension or heart failure. The aim of this study was to define the possible role of I(1)-imidazoline receptors in the regulation of atrial natriuretic peptide (ANP) release in hypertrophied atria. Experiments were performed on isolated, perfused, ...

BACKGROUND In patients with chronic heart failure (CHF), plasma endothelin-1 (ET-1) levels are increased. We studied whether the cardiac ET-receptor system is altered in CHF patients. METHODS AND RESULTS We assessed ET-evoked inositol phosphate (IP) formation in slices from right atria and left ventricles from 6 potential heart transplant donors (NFH) and 15 patients with end-stage CHF; in me...