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.
Premature Ventricular Contractions. Description. Premature ventricular contractions (PVCs) are beats which are initiated in the ventricles or lower chambers of the heart, prematurely. As opposed to PACs, when the SA node (the natural pacemaker of the heart) gets interrupted, PVCs do not interrupt the SA node.