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. The heart has four chambers. The upper two chambers are the atria, and the lower two chambers are the ventricles.
When Can I See the Perseids? The Perseid meteor shower, one of the brighter meteor showers of the year, occurs every year between July 17 and August 24. The shower tends to peak around August 9-13. The best time to view the Perseids, and most other meteor showers, is when the sky is the darkest.
A meteor shower is a spike in the number of meteors or shooting stars that streak through the night sky. Most meteor showers are spawned by comets. As a comet orbits the Sun it sheds an icy, dusty debris stream along its orbit. If Earth travels through this stream, we will see a meteor shower.