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.
There are four main characteristics of premature ventricular contractions (PVCs): 1  They are premature. That is they occur earlier than you would expect if you were to measure the previous R to R intervals.  They are ectopic. Meaning originating outside of the SA node.