Intrinsic | Idiopathic degenerative disorder | Ischemic heart disease | Chronic ischemia | Acute myocardial infarction | Hypertensive heart disease | Cardiomyopathy | Trauma | Surgery for congenital heart disease | Heart transplant | Inflammation | Collagen vascular disease | Rheumatic fever | Pericarditis | Infection | Viral myocarditis | Lyme disease (Borrelia burgdorfer I) | Neuromuscular disorder | Friedreich ataxia | X-linked muscular dystrophy | Familial disorder | | Extrinsic | Drugs | Antiarrhythmic agents | Class IA - quinidine, procainamide | Class IC - propafenone, flecainide | Class II - β-blockers | Class III - sotalol, amiodarone, dronedarone | Class IV - diltiazem, verapamil | Cardiac glycosides | Antihypertensive agents | Clonidine, reserpine, methyldopa | Antipsychotic agents | Lithium, phenothiazines, amitriptyline | Autonomically mediated | Vasovagal syncope (cardioinhibitory) | Carotid sinus hypersensitivity | Hypothyroidism | Intracranial hypertension | Hypothermia | Hyperkalemia | Hypoxia | Anorexia nervosa | |