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.
Back to TopCauses. Acute tubular necrosis (ATN) is usually caused by a lack of oxygen to the kidney tissues (ischemia of the kidneys). It may also occur if the kidney cells are damaged by a poison or harmful substance. The internal structures of the kidney, particularly the tissues of the kidney tubule, become damaged or destroyed.