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.
The following causes of Atrial fibrillation are diseases or conditions that affect more than 1 million people in the USA: 1  Atrial fibrillation. 2  Congenital heart defects. 3  Graves' disease. 4  Heart failure. 5  Myocardial infarction. 6  Rheumatic fever.7  more causes...Â».he following causes of Atrial fibrillation are diseases or medical conditions that affect more than 10 million people in the USA: 1  Coronary heart disease. 2  Diabetes Mellitus. 3  Hypertension, systemic. 4  Ischaemic heart disease. 5  more causes...Â».