Action potential shortening rescues atrial calcium alternans

Alternans in human atrial monophasic action potenial.

This report describes the case of a patient with a supraventricular tachycardia with a ventricular rate of 109/min and no visible P waves in the electrocardiogram. The recording of the monophasic action potential of the right atrium disclosed an atrial tachycardia with a rate of 218/min. There was an alternans of the phase 2 of repolarisation in the action potential. This report emphasises the ...

Inhibition of Atrial Action Potentials Alternans by Calcium-Activated Chloride Current Blockade - Simulation Study

Atrial fibrillation (AF) is the most common cardiac arrhythmia. Atrial action potential (AP) alternans appearance during atrial flutter play a determinant role as AF precursor. AP alternans involves intracellular calcium concentration alternation that affects calcium dependent currents like INaCa and IClCa. In this study, a modified rabbit atrial AP mode, that includes ICl,Ca formulation is use...

Chronic myocardial infarction promotes atrial action potential alternans, afterdepolarizations, and fibrillation

AIMS Atrial fibrillation (AF) is increased in patients with heart failure resulting from myocardial infarction (MI). We aimed to determine the effects of chronic ventricular MI in rabbits on the susceptibility to AF, and underlying atrial electrophysiological and Ca(2+)-handling mechanisms. METHODS AND RESULTS In Langendorff-perfused rabbit hearts, under β-adrenergic stimulation with isoprote...

Sympathetic Nervous Regulation of Calcium and Action Potential Alternans in the Intact Heart

Rationale: Arrhythmogenic cardiac alternans are thought to be an important determinant for the initiation of ventricular fibrillation. There is limited information on the effects of sympathetic nerve stimulation (SNS) on alternans in the intact heart and the conclusions of existing studies, focused on investigating electrical alternans, are conflicted. Meanwhile, several lines of evidence impli...

Spatio-temporal Evolution and Prediction of Action Potential Duration and Calcium Alternans in the Heart