**1.1 Types of AF**

To be considered as AF, the arrhythmia must be documented by ECG and lasts >30 seconds [3]. If these two features are met, the arrhythmia is called clinical AF, and if not, the arrhythmia is considered as an rapid atrial rate episode or subclinical AF.

Based on the time of evolution, the AF is classified as [4]:


## **1.2 Predisposing factor for AF**

There are a number of factors that predispose to AF, including [5–7]:


These risk factors contribute to the damage in the atrial as changes in the structure, architecture, contractility, and electrophysiology that may lead to the dilatation, fibrosis, dysfunction, and distortion conduction in the left atrial. This cumulative damage is the substrate on which atrial fibrillation develops [8].
