Atrial fibrillation is diagnosed with the electrocardiogram, an investigation performed routinely whenever irregular heartbeat is suspected.  Characteristic findings are the absence of P waves, with unorganized electrical activity in their place, and irregularity of R-R interval due to irregular conduction of impulses to the ventricles. If paroxysmal atrial fibrillation is suspected and 12-lead ECG is normal, usage of a 24-hour ambulatory ECG monitor is recommended. Typical electrocardiogram findings in a patient with atrial fibrillation are absent P waves, irregularly irregular ventricular response rate, and an atrial rate that ranges from 400 to 700 BPM. A rapid, irregular, sustained, wide-QRS-complex tachycardia strongly suggests atrial fibrillation (AF) with conduction over an accessory pathway or atrial fibrillation (AF) with underlying bundle-branch block.
Atrial fibrillation electrocardiogram
Ventricular fibrillation electrocardiogram
Atrial flutter electrocardiogram
Left ventricular aneurysm electrocardiogram
Ventricular tachycardia electrocardiogram
Atrial fibrillation physical examination
Pacemaker syndrome electrocardiogram
Atrial flutter physical examination