Premature ventricular contractions (PVC) are premature heartbeats originating from the ventricles of the heart. PVC’s are premature because they occur before the regular heartbeat. Symptoms are often not presented with premature ventricular contractions.
During a pvc, the ventricle electrically discharges (and contracts) prematurely before the normal electrical signals arrive from the SA node. These premature discharges are due to electrical “irritability” of the heart muscle of the ventricles, and can be caused by heart attacks, electrolyte imbalances, lack of oxygen, or medications. Immediately after a premature ventricular contraction, the electrical system of the heart resets. This resetting causes a brief pause (called a ‘compensatory pause’) in the heartbeat and some patients report feeling the heart briefly stopping after a pvc. PVC’s without any other electrical or structural abnormality are of virtually no diagnostic nor prognostic value at all. They occur in everyone in various sorts of patterns, and again, absent any structural or neurocardiological disease, they have no real meaning. They can, however, be very alarming when they occur, and can provoke a good deal of anxiety which, unfortunately causes the release of adrenaline, which in turn makes the heart muscle more irritable, and often thus sets off yet more PVC’s sometimes making the sufferer a nervous wreck. This is truly unfortunate, because without significant left ventricular dysfunction PVC’s have no meaning at all (and even with LV dysfunction they are only an indicator, not a cause, of potential trouble).
