Their high calcium content is usually the star of the show, but donât let it blind you to everything else in the can. 1  Sardines also deliver: 2  Selenium (69%) 3  Phosphorus (45%) 4  Iron (15%) 5  Magnesium (9%) 6  Copper (9%) 7  Zinc (8%)
Premature ventricular contractions (PVCs, PVC) are premature heartbeats originating from the ventricles of the heart. Premature ventricular contractions are premature because they occur before the regular heartbeat. Normal function of the heart. The heart has four chambers.
slide 1 of 9. What are PVCs? Premature ventricular complexes are irregular heartbeats caused by the ventricles (the lower heart chambers) contracting earlier than normal. When the heart beats normally, the sinoatrial node in the right atrium (upper chamber) sends an electrical impulse across the atria to the ventricles, causing them to contract.