Risk factors for the ventricular tachycardia as a cause of<unk><unk>  tachycardia include a history of prior myocardial infarction, a history of congestive heart failure, and a history of recent angina pectoris.  These three historical features have positive predictive values for VT of > 95% in a small study, but sensitivities of 66%, 24%, and 24%, respectively. <unk><unk>  tachycardia will be due to VT in 98% of cases if there's a history of structural heart disease.  Only 7% of patients with SVT with aberrancy will have had a prior myocardial infarction (MI).
Wide complex tachycardia risk factors
Pulseless ventricular tachycardia risk factors
Catecholaminergic polymorphic ventricular tachycardia risk factors
Supraventricular tachycardia risk factors
Junctional tachycardia other diagnostic studies
Second degree AV block other diagnostic studies
Third degree AV block other diagnostic studies
Premature atrial contraction risk factors