Wide complex tachycardias. Differential diagnosis and management.

The majority of wide complex tachycardias are secondary to VT. The differential diagnosis of wide complex tachycardia also includes SVT with aberrancy or underlying bundle branch block and antegrade SVT conduction over an accessory pathway (antidromic SVT). VT is usually the result of reentry and most commonly arises in an area of diseased myocardium in the setting of previous myocardial infarction or cardiomyopathy. VT, however, can also occur in patients with structurally normal hearts. Criteria useful in diagnosis of wide complex tachycardia include clinical criteria (presence of structural heart disease or a history of previous myocardial infarction) and electrocardiographic criteria (the presence of capture or fusion beats, relation of atrial or ventricular activity, QRS duration and axis, and morphology). The acute management of wide complex tachycardia includes cardioversion and intravenous pharmacologic therapy. Almost all patients with VT require chronic therapy, although in rare patients treatment of acute precipitating factors may be sufficient. While pharmacologic therapy has been the mainstay of treatment for these patients, there have been many exciting advances using surgical, device, and ablative therapies.