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.
A board, typically with a hole for the thumb, which an artist can hold while painting and on which colors are mixed. 2. a. The range of colors used in a visual medium, in a picture, or by an artist: a limited palette.
The meaning of the word palette has extended beyond actual colors to include figurative colors. A musician can use a palette of tones and modes. Either way it is a limited selection from all things available. Don't confuse this word with the homophone palate which refers to your sense of taste. Both words come to English through Old French but have different Latin roots.