A answered. Atrial fibrillation can be caused by a number of different things that predispose the heart to arrhythmias. Most commonly, longstanding high blood pressure is the cause. Other causes include heart disease such as blockage in the coronary vessels or diseases such as pneumonia or COPD.
Definition: When an artist deliberately restricts the number of colors they use in a painting, they're said to be using a limited palette. (A palette being what paints are squeezed out onto, ready for use.). Also Known As: Restricted palette.
Speed painting is an artistic technique where the artist has a limited time to finish the work. The time can vary, usually a duration is set from several minutes to a few hours. Unlike sketches, speed paintings may be considered finished after the time limit is up- it is generally accepted among painters that if a piece is altered after the allotted time, it can no longer be truly considered a speedpainting.