Table 1 Classification of syncope

Aortic stenosis, hypertrophic cardiomyopathy, pulmonary embolism, aortic dissection, myocardial infarction, left atrial myxoma, cardiac tamponade, atrioventricular block, sick sinus syndrome, tachyarrhythmia, bradyarrhythmia

Neurally mediated (reflex mechanisms)

Vasovagal, situational (micturition, laughter, tussive, defecation, postprandial, sneeze, swallow), orthostatic syncope, carotid sinus syncope

Neurologic

Transient ischemic attack, subclavian steal syndrome, Takayasu disease, seizure

Metabolic

Hypoxia, hypoglycemia, hyperventilation

Psychiatric

Panic disorder, conversion reaction, hysteria

Drug-induced

Vasodilators (nitrates, calcium channel blockers, angiotensin-converting enzyme inhibitors), phenothiazines, antidepressants (tricyclic agents, monoamine oxidase inhibitors), central nervous system depressants (barbiturates), drugs associated with torsades de pointes (quinidine, procainamide, disopyramide, amiodarone, sotalol, flecainide), diuretics, digitalis, insulin, marijuana, alcohol, cocaine

Unknown origin