Expert: doctornihil replied 6 years ago. Hi, The hypoplasia of A1 segment of the right anterior cerebral artery and of the P1 segment of the right posterior cerebral artery is a congenital variation ('birth defect'), which increases the chances of ischemic stroke (reduced blood circulation in the brain). Ask Your Own Medical Question.
Premature ventricular contractions (PVCs) are extra, abnormal heartbeats that begin in one of your heart's two lower pumping chambers (ventricles).These extra beats disrupt your regular heart rhythm, sometimes causing you to feel a flip-flop or skipped beat in your chest.remature ventricular contractions (PVCs) are extra, abnormal heartbeats that begin in one of your heart's two lower pumping chambers (ventricles).
1 Photovoltaic (PV) systems, which convert sunlight directly to electricity by means of PV cells made of semiconductor materials. 2  Concentrating solar power (CSP) systems, which concentrate the sun's energy using reflective devices such as troughs or mirror panels to produce heat that is then used to generate electricity.