<unk>  (or multiform)<unk><unk>  <unk>  is an abnormal heart rhythm, specifically a type of supraventricular<unk> , that is particularly common in older people and is associated with exacerbations of chronic obstructive pulmonary disease (COPD). Normally, the heart rate is controlled by a cluster of cells called the sinoatrial node (SA node). When a number of different clusters of cells outside the SA node take over control of the heart rate, and the rate exceeds 100 beats per minute, this is called<unk>  (if the heart rate is ≤100, this is technically not a<unk>  and it is then termed<unk><unk>  rhythm). 'Multiform' simply describes the variable P wave shapes and is an observation,<unk> ' is an inference about the underlying cause. Although these are interchangeable terms, some purists prefer the former nomenclature since it does not presume any underlying mechanism.
Multifocal atrial tachycardia
Wandering atrial pacemaker
Atrioventricular reentrant tachycardia
AV nodal reentrant tachycardia
Second-degree atrioventricular block
Third-degree atrioventricular block
First-degree atrioventricular block
Sinus arrhythmia