Atrial fibrillation (A-tre-al fi-bri-LA-shun), or AF, is the most common type of arrhythmia (ah-RITH-me-ah). An arrhythmia is a problem with the rate or rhythm of the heartbeat. During an arrhythmia, the heart can beat too fast, too slow, or with an irregular rhythm.
Detailed Synonyms for also known as in English. also known as: also known as adv. also known as so called; alias; known as; named; what they call; going by the name of; also known as; called so called adj. alias adv. known as adj. named adj. what they call adj.
The other in- is a Latin negative prefix, equivalent to English un-. Some of its other forms are im-, il-, and ir-. This prefix is used to indicate a negative or the absence of something. The word infamous uses the negative prefix. It does not mean 'not famous'; it means 'having an extremely bad repuatation' and hence 'wicked'. This is because it's not an English formation of in- and famous, but a borrowing of Latin infamis 'without a reputation', formed from the sense of famis in Latin meaning 'a reputation'.