My dr has just told me that i have a rare pvcs that is benign but he doesn't know where its coming from. how can it be benign if he don't know where fro?

Benign PVCs: Intermittent, sporadic pvcs are extremely common and most people will get them some time or other, usually at times of stress. They are called "benign" because they are not associated with any particular pathologic cause. The cause is stress and excessive activation of your Adrenalin system. Intermittent Adrenalin discharges associated with stress are a normal part of the human experience.

Depnds: Pvcs can be benign or very serious, it depends if the left ventricle is normal or not, history of syncope etc., in a healthy patient with normal ventricle just noting a PVC is usually benign.