without having your EKG in front of me I'd guess that you have something called a "right bundle branch block", which is just as you described--something going on with the conduction system by which electrical impulses are transmitted to your ventricles.

A stress test is a good idea as RBBB can be caused by coronary artery disease. The prognosis is usually very good if there is no evidence for significant coronary disease. I suspect that if you ride a bicycle regularly without any symptoms of chest pressure, trouble breathing, lightheadedness that you will probably do fine on your stress test.

One of the symptoms that you should take seriously is fainting or severe lightheadedness/dizziness as it may indicate more significant problems with heart conduction.

good luck.