<unk>  is characterized by a heart rate more than 100 beats per minute associated with a QRS interval of more than 120 ms.  When<unk>  is present, it is important to determine whether the tachycardia is ventricular tachycardia or supraventricular tachycardia with aberrancy.  The diagnosis of<unk>  is very challenging as there is no fixed criteria to accurately determine the cause and type of the<unk> . Hemodynamically unstable patients should receive urgent synchronized cardioversion unless the patient has polymorphic ventricular tachycardia for which unsynchronized cardioversion should be performed.  If the QRS complex and the T wave can't be distinguished in unstable patients, then the patient should receive unsynchronized cardioversion.
Wide complex tachycardia
Narrow complex tachycardia
Fascicular VT
Supraventricular arrhythmias
Junctional tachycardia
Ventricular escape beat
Second degree AV block
Sinus arrhythmia