under contract means there is an offer on it already and the buyer and seller are negotiating back and forth to come to an agreement. if ya need any more help just e-mail me. Lori lspalletta Â· 1 decade ago
Premature atrial complexes are caused by abnormal electrical impulses transmitted by the atria (either of the upper chambers of the heart). The abnormal electrical impulses cause contractions of the upper chamber of the heart earlier than expected. Such premature beats are generally harmless. slide 1 of 7.
Paroxysmal atrial tachycardia may be caused by several different things. The fast rate may be triggered by a premature atrial beat that sends an impulse along an abnormal electrical path to the ventricles.Other causes stem from anxiety, stimulants, overactive thyroid, and in some women, the onset of menstruation.aroxysmal atrial tachycardia may be caused by several different things. The fast rate may be triggered by a premature atrial beat that sends an impulse along an abnormal electrical path to the ventricles.