Recommendations: diagnostic criteria with initial evaluation

^aClass of recommendation.

^bLevel of evidence.

AV = atrioventricular; BBB = bundle branch block; ECG = electrocardiogram; ICD = implantable cardioverter defibrillator; OH = orthostatic hypotension; SVT = supraventricular tachycardia; VVS = vasovagal syncope; VT = ventricular tachycardia.