The diseases have been categorized as patches (cause dead spots or patches in the lawn), rings (cause rings of dead or affected grass), or leaf blight (affect individual blades of grass, often over a wide area and no distinct patch or ring pattern may be noticeable).
PVR, abbreviation for pulmonary vascular resistance. To measure changes in blood vessel size or changes in gas volume in the lungs to assist in diagnosing diseases such as deep vein thrombosis (DVT), chronic obstructive pulmonary disease (COPD), and some peripheral vascular disorders. Veins, arteries, and lungs. None.
Definition. A premature ventricular beat (PVB) is an extra heartbeat caused by abnormal electrical activity. It starts in the ventricles (the lower chambers of the heart) before a normal heartbeat occurs. PVB interferes with the heartâs normal rhythm and causes a pause before the next heartbeat. It may feel like a heartbeat is skipped. PVBs are common, especially among the elderly.