Our research team studies the physiological and pharmacological modulation of ion channels present in the plasma membrane of human cardiac myocytes. In order to assess this issue, we use the whole-cell configuration of the patch-clamp technique. Ionic channels are membrane proteins able to generate and maintain the action potential duration and also to maintain the resting membrane potential. Therefore, these molecules are responsible, among other functions, of muscle contraction, cardiac rhythm and synaptic transmission. We focus our resarch interest in the potassium channels present into the human myocardium. In the heart, IKur current represents the more important potassium outward currents during the atrial repolarization. The IKur is generated after the activation of Kv1.5 channels. Because these channels are responsible of the atrial cardic repolarization, they represent pharmacological targets of antiarrhythmic drugs useful in the treatment of cardiac arrhythmias.