Sinus Tachycardia, Heart Palpitations. What Are The Risks?

What do you think about frequent Sinus Tachycardia and heart palpitations in a 23 year old male? Palpitations are assumed to be caused by PVCs in the left Ventricle as its corrective contraction is so extremely powerful... However, my local ER declined any request for confirmation as I have a history of mental illness. It is also notable that because of the sheer energy of this beat, it can sometimes trigger another, and have both preceeded and succeeded one Normal Sinus Cycle. Again, never three or more consecutive PVCs or history of any type of Ventricular Dysrhythmia. I should also note that there is no ST elevation before I forget. What risks are there for a 23 year old male with frequent PVCs and many other risk factors for Coronary Artery Disease , such as smoking, anxiety, alcohol use, and heredity, to actually have cardiovascular complications, such as Myocardial Infarction, a Stroke, or otherwise? Lastly, what important questions should I ask my Primary Care Provider, and for that matter, did I miss any questions just now...? Thanks, doc. - Bruce History: Bipolar Disorder, Mixed Lipidemia, Panic Disorder, Generalized Anxiety Disorder