Search results for "Atrial Function"
showing 2 items of 22 documents
Tetrodotoxin slightly shortens action potential duration in ventricular but not in atrial heart muscle.
1988
Tetrodotoxin (TTX), at concentrations significantly decreasing maximal upstroke velocity (dV/dtmax) of the action potential, exerted variable effects on action potential duration (APD) in different myocardial preparations. APD was virtually unchanged by tetrodotoxin in the guinea pig atrium, but slightly shortened in the guinea pig ventricle at maximally effective concentrations. In the human ventricle, both dV/dtmax and APD were reduced in the same concentration range of TTX. These results suggest that a TTX-sensitive sodium current significantly contributes to the repolarization phase of the action potential in ventricular but not in atrial heart muscle.
The controversial relationship between exercise and atrial fibrillation: clinical studies and pathophysiological mechanisms
2015
Atrial fibrillation is the most common clinically significant arrhythmia observed both in the general population and in competitive athletes. The most important risk factors are all preventable by regular physical activity. However, although the benefits of moderate physical activity in controlling cardiovascular risk factors and decreasing the risk of atrial fibrillation have been extensively proved, concerns have arisen about the potential negative effects of vigorous exercise, particularly in endurance athletes. Furthermore, in a subset of patients with atrial fibrillation younger than 60 years, routine evaluation does not reveal any cardiovascular disease or any other known causal facto…