With the first ribs fixed by neck muscles (scalene muscles and sternocleidomastoid muscle), the intercostals muscles (especially external intercostal muscles and interchondral part of internal intercostal muscles of opposite side), elevate the 2nd to 12th ribs and thus act as inspiratory muscles.
Medical Dictionary. arrhythmia. play. noun arÂ·rhythÂ·mia \Ä-Ërith-mÄ-É\. Medical Definition of arrhythmia. : an alteration in rhythm of the heartbeat either in time or force.
An arrhythmia describes an irregular heartbeat - the heart may beat too fast (tachycardia), too slowly (bradycardia), too early (premature contraction), or irregularly (fibrillation). Arrhythmias occur when the electrical signals to the heart that coordinate heartbeats are not working properly. Many heart arrhythmias are harmless.