Dictionary entry overview: What does spiny mean? â¢ SPINY (adjective) The adjective SPINY has 2 senses: 1. having spines 2. having or covered with protective barbs or quills or spines or thorns or setae etc. Familiarity information: SPINY used as an adjective is rare.
Atrial Flutter Overview. Atrial flutter is an abnormality of the heart rhythm, resulting in a rapid and sometimes irregular heartbeat. Such abnormalities, whether in the rate or regularity of the heartbeat, are known as arrhythmias. The beating of the heart is controlled by electrical impulses.
1 Atrial fibrillation. 2  Atrial fibrillation is a very common irregular heart rhythm that causes the atria, the upper chambers of the heart, to contract abnormally. 3  Atrial flutter. 4  This is an arrhythmia caused by one or more rapid circuits in the atrium.