A detailed history should be obtained from patients with wide complex tachycardia, with special focus on ischemic heart diseases, structural cardiac diseases, presence of a pacemaker and current medications. In addition, the patient should be asked about any family history of sudden cardiac death, channelopathy and other inherited arrhythmias.

The patient should be asked about drugs that are associated with ventricular tachycardia and if there is a history of ischemic heart disease which would dramatically increase the odds that the rhythm is VT. Wide complex tachycardia will be due to VT in 80% of cases and will be due to VT in 98% of cases if there’s a history of either acute MI or structural heart disease. Only 7% of patients with SVT will have had a prior myocardial infarction (MI). VT or an accelerated idioventricular rhythm can be seen following reperfusion in STEMI. Digoxin, antiarrhythmics, phenothiazines, tricyclic antidepressants, and pheochromocytoma may also cause VT. Recent procedures such as cardiac catheterization, DC countershock, repair of congenital lesions are all associated with VT. A family history of sudden cardiac death, a history of a channelopathy associated with arrhythmias, and the hereditary long QT syndrome, and Brugada syndrome are all associated with VT.

• Shortness of breath
• Syncope
• Sudden cardiac death would suggest a diagnosis of ventricular tachycardia