Ventricular Premature Beats
Ventricular premature beats, or VPBs (also called VPCs or PVCs for premature ventricular contractions), are a common cause of palpitations. They are similar to atrial premature beats since they disrupt the heart rhythm and result in an irregular pulse. However, APBs arise from the atria, while VPBs arise from the ventricles. Since the abnormal heart beat arises from the bottom chambers of the heart it is accompanied by reversal of the normal timing of the heart chambers. In other words, instead of the atria contracting first and the ventricles following, the ventricles contract first. Often, the atrial contraction follows, but because the AV valves are in a closed position during ventricular contraction the blood stored in the atrium has no where to go except backwards into the veins. This can cause a fullness in the neck and chest (often described as "my heart is in my throat"). For you trivia fanatics, the jugular venous pulsation in the neck often shoots up briefly when this happens and the medical term for this is a "cannon A-wave" (because it shoots up like a cannon). The compensatory pause that occurs after a VPB may be longer than after an ABP and so the overfilling of the ventricles and the resultant "heavy" beat following the pause can be exaggerated. Ventricular premature beats occur normally in most people, and they usually increase with age. Sometimes VPBs do not cause symptoms (those patients should consider themselves lucky!). If they cause severe palpitations, medical therapy can be used to suppress most of them. However, VPBs are usually benign, and they don't require therapy unless the symptoms are intolerable. Sometimes VPBs are associated with heart disease such as coronary artery blockages or heart muscle problems, so it is reasonable for a physician to send the patient with VPBs for further cardiac testing. Generally, if there is no other heart disease, VPBs should not be treated unless the symptoms are severe. If significant heart disease is present, VPBs can be a marker of increased risk of more severe rhythm problems such as ventricular tachycardia (see the next chapter), and further testing may be beneficial to see if that patient could get in trouble in the future.