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.
ECG Features of Premature Atrial Complex (PAC) PACs usually have the following features: An abnormal (non-sinus) P wave is followed by a QRS complex. The P wave typically has a different morphology and axis to the sinus P waves.