In atrial fibrillation, the electrical impulse of the heart is not regular. 1  Parts of the heart cannot contract in an organized pattern. 2  As a result, the heart cannot pump enough blood to meet the body's needs.
Synonyms, crossword answers and other related words for IN A NUTSHELL. summed up briefly; gave the facts in a nutshell; just tell me the story in a nutshell; explained the situation in a nutshell.
Definition of NUT. 1. a (1) : a hard-shelled dry fruit or seed with a separable rind or shell and interior kernel (2) : the kernel of a nut b: a dry indehiscent one-seeded fruit with a woody pericarp.2. a: a hard problem or undertaking b: core, heart.3.efinition of NUT for Kids. 1. : a dry fruit or seed with a firm inner kernel and a hard shell. 2. : the often edible kernel of a nut. 3. : a small piece of metal with a hole through it that can be screwed onto a bolt for tightening or holding something.