DDx -1. Arrythmias - VTach/VFib, AV Block, bradycardia, Sick Sinus Syndrome, PSVT, WPW, Prolonged QT Syn., PM related
2. Cardiac - Aortic Stenosis, Mitral Stenosis, IHSS, Left Atrial Myxoma, Prosthetic Valve Dysfunction, Pulmonary Stenosis, PPH, MVP , Tamponade, Congenital (Fallot, Eisenmenger), PE
3. Meds - ETOH, diuretics, vasodilators, antiarhythmics, antihypertenisves, antianginal, antipsychotic, cocaine, drug overdose
4. Metabolic - Hypoglycemia, hypoxia, hyperventilation
5. Other - Vasovagal, valsalva, post-micturation or defecation, orthostatic, post prandial, gastic distension, vertigo, cough, seizure, migraine, carotid sinus, TIA-CVA, subclavian steal, anxiety, panic disorder, fluid loss, bed rest