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.
slide 1 of 9. What are PVCs? Premature ventricular complexes are irregular heartbeats caused by the ventricles (the lower heart chambers) contracting earlier than normal. When the heart beats normally, the sinoatrial node in the right atrium (upper chamber) sends an electrical impulse across the atria to the ventricles, causing them to contract.