Bradycardia causes

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Bradycardia Microchapters



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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: M.Umer Tariq [2]; Ogheneochuko Ajari, MB.BS, MS [3]


Pathologic bradycardias are caused by disorders of impulse generation (impaired automaticity at SA node), impulse conduction (heart block), or escape pacemakers and rhythms. Bradycardia can be underlain by several causes, which are best divided into cardiac and non-cardiac causes or based on the location of the abnormality.


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Life Threatening Causes

Life-threatening causes include conditions which may result in death or permanent disability within 24 hours if left untreated.

Common Causes

Causes by Organ System

Cardiovascular Acute coronary syndrome, Acute myocardial infarction, Acute rheumatic fever, Andersen cardiodysrhythmic periodic paralysis, Aspergillosis myocarditis, Atherosclerosis, Atrial septal defect, Atrioventricular block, Brugada syndrome, Calcific aortic stenosis, Cardiac arrhythmia, Cardiac catheterization, Cardiac glycosides, Cardiac transplantation, Cardiac tumor, Cardioinhibitory syncope, Cardiomyopathy, Cardioversion, Carotid sinus hypersensitivity, Complete heart block, Congenital heart block, Congenital heart disease, Congestive heart failure, Coronary artery bypass grafting, Coronary heart disease, Coronary ischemia, Coronary reperfusion therapy, Diabetes mellitus, Dilated cardiomyopathy, Ebstein’s anomaly, Electrophysiological studies, Endocardial cushion defect, Endocarditis, Enhanced vagal tone, Fontan procedure, High fitness level, Hypersensitive carotid sinus syndrome, Hypertension, Hypertensive heart disease, Hypertrophic cardiomyopathy alcohol septal ablation, Hypertrophic cardiomyopathy, Hypervagotonia, Idiopathic heart block, Idiopathic hypereosinophilic syndrome, Infraclavicular brachial plexus block, Ischemic heart disease, Isorhythmic a-v dissociation, Jervell and lange-nielsen syndrome, Junctional rhythms, Lateral medullary syndrome, Left ventricular noncompaction, Lenegre's disease, Lev's disease, Long qt syndrome, Lown-ganong-levine syndrome, Lqt type 4, Lqt4 mutation, Mahaim fiber tachycardia, Maze procedure, Micturition syncope, Mitral regurgitation, Mitral stenosis, Mitral valve prolapse, Myocardial bridging, Myocardial contusion, Myocardial infarction  , Myocardial ischaemia, Myocardial rupture, Myocarditis, Neurocardiogenic syncope, Noncompaction cardiomyopathy, Normal variants of pr prolongation, Normal variation in vagal tone, Nstemi, Pacemaker malfunction, Paroxysmal supraventricular tachycardia, Pericarditis, Permanent pacemaker, Peroneal muscular atrophy, Post aortic valve replacement, Post catheter ablation for arrhythmias, Post closure of a ventricular septal defect, Post mitral valve replacement, Preexcitation syndrome, Premature atrial beats, Pulmonary embolism, Pulmonary stenosis, Restrictive cardiomyopathy, Rheumatic mitral valve disease, Romano-ward syndrome, Sick sinus syndrome, Sinoatrial block, Sinus arrest, Sinus bradycardia, Sinus node disease, Sinus node fibrosis, Stemi, Subarachnoid hemorrhage, Sustained ventricular tachycardia, Tachycardia-bradycardia syndrome, Takotsubo cardiomyopathy, Tetralogy of fallot, Tilt testing, Timothy syndrome, Trained athletes, Transcatheter aortic valve implantation, Transposition of the great vessels, Vagal maneuvers, Vagal reaction, Valsalva maneuver, Valvular heart disease, Vasovagal syncope, Ventricular septal defect, Wolff-parkinson-white syndrome
Chemical/Poisoning 5-fluorouracil, Alcohol intoxication, All-trans retinoic acid, Carbamate poisoning, Carbamates, Crizotinib toxicity, Digitalis, Dimethyl sulfoxide, Disopyramide, Fentanyl, Heart block, Heart surgery, Heat exhaustion, Isoprenaline infusion, Lily of the valley poisoning, Magnesium, Organophosphate poisoning, Parathion poisoning, Poisonous spider bites, Pyrethroid poisoning, Scorpion toxin, Toluene sniffing
Dental No underlying causes
Dermatologic Dermatomyositis, Obstructive jaundice
Drug Side Effect Acetylcholine, Alfentanil, Ambenonium, Amiodarone, Amlodipine, Amphetamines, Anidulafungin, Anthracyclines, Antiarrhythmic drugs, Atenolol, Atetylcholine, Barbiturate, Berberine, Beta-blockers, Bethanechol, Bortezomib, Bupivacaine, Calcium channel blocker, Cannabis, Carbamazepine, Celecoxib, Ceritinib, Certain medications, Cilobradine, Cimetidine, Citalopram, Clonidine, Cocaine, Dapoxetine, Daunorubicin, Deserpidine, Dexmedetomidine, Digoxin, Diltiazem, Diphenhydramine, Distigmine, Dobutamine, Dolasetron, Donepezil, Doxorubicin, Dronedarone, Drugs, Edrophonium, Ephedrine, Epirubicin, Eslicarbazepine acetate, Febuxostat, Fesoterodine, Fingolimod, Flecainide, Flumazenil, Fluoxetine, Fluvoxamine, Fosphenytoin, Granisetron, Grayanotoxin, Guanethidine, Guanfacine, H2 receptor antagonist, Halothane, Hyoscyamine, Ibutilide, Idarubicin, Isoproterenol, Ivabradine, Labetalol, Lacosamide, Lanatoside c, Lanreotide, Lidocaine, Lithium, Lofexidine, Medications, Mefloquine, Mepivacaine, Mesalamine, Methyldopa, Methylprednisolone, Mexiletine, Morphine, Muscarine, Nadolol, Nefazodone, Nelfinavir, Neostigmine, Nerve agent, Nicorandil, Paclitaxel, Paliperidone, Palonosetron, Phenothiazine, Phenylephrine, Phenytoin, Physostigmine, Procainamide, Propafenone, Propanolol, Propofol, Propoxyphene, Propranolol, Pyridostigmine, Quinidine, Rabeprazole, Regadenoson, Remifentanil, Rescinnamine, Reserpine, Rilmenidine, Ropivacaine, Salbutamol, Sedative, Somatostatin, Sotalol, Sufentanil, Suxamethonium, Sympathomimetic agents, Tacrine, Tacrolimus, Terodiline, Theophylline, Thiamylal, Thiazides, Timolol, Tolterodine, Topical cocaine, Tramadol, Tricyclic antidepressants, Urapidil, Vecuronium, Verapamil, Veratridine (false hellebore), Zaleplon, Zatebradine
Ear Nose Throat Esophageal or nasopharyngeal stimulation, Sjogren's syndrome
Endocrine Cretinism, Cushing's syndrome, Hashimoto's thyroiditis, Hyperthyroidism, Hypothyroidism, Myxedema, Profound hypothyroidism, Thyrotoxic periodic paralysis, Thyrotoxicosis
Environmental No underlying causes
Gastroenterologic Nausea, Vomiting
Genetic Becker muscular dystrophy, Fabry disease, Hcm, Hcn4 mutation, Hereditary neuromuscular disease, Jervell and lange-nielsen syndrome, Kearns-sayre syndrome, Mitochondrial genome inherited conditions, Nail-patella syndrome, Scn5a mutation, Timothy syndrome, X-linked inherited conditions
Hematologic Anemia, Churg-strauss syndrome, Hemochromatosis, Hypercalcemia, Hypercapnia, Hyperkalemia, Hypermagnesemia, Hypocalcemia, Hypoglycemia, Hypokalemia, Hypomagnesemia, Hypoxia, Sepsis, Thalassemia major
Iatrogenic No underlying causes
Infectious Disease Aspergillosis myocarditis, Brucellosis, Chagas disease, Dengue fever, Diptheria, Legionellosis, Leptospirosis, Lyme disease, Malaria, Meningitis, Pneumonia, Protozoal infection, Q fever, Rabies, Rocky mountain spotted fever, Salmonellosis, Sepsis, Septic shock, Trichinosis, Tuberculosis, Typhoid fever, Typhus, Varicella zoster, Viral hemorrhagic fever, Yellow fever
Musculoskeletal/Orthopedic Arnold-chiari malformation, Dermatomyositis, Duchenne's muscular dystrophy, Emery-dreifuss muscular dystrophy, x-linked, Erb's dystrophy, Hereditary neuromuscular disease, Limb-girdle muscular dystrophy type 1b (lgmd1b), Mitochondrial myopathy, Muscular dystrophy, Myotonic dystrophy, Myotonic muscular dystrophy
Neurologic Bezold-jarisch reflex, Degenerative diseases, Diabetic neuropathy, Epilepsy, Friedreich ataxia, Increased intracranial pressure, Miller-dieker syndrome, Neurocardiogenic syncope, Raised intracranial pressure, Severe brain injury, Sleep apnea, Sleep, Timothy syndrome
Nutritional/Metabolic Cerebral edema, Diabetes mellitus, Diabetic ketoacidosis, Diabetic neuropathy, Glycogen storage disease type ii, Glycogenosis type 2b, Hypoglycemia, Kwashiorkor, Malnutrition, Metabolic acidosis, Obesity, Pompe disease, Severe anorexia nervosa, Starvation, Very low birth weight infants
Obstetric/Gynecologic Fetal distress, Pregnancy
Oncologic Hodgkin disease, Hodgkin lymphoma, Multiple myeloma, Pheochromocytoma, Tumor lysis syndrome, Tumor
Ophthalmologic No underlying causes
Overdose/Toxicity No underlying causes
Psychiatric Anorexia nervosa, Severe anorexia nervosa
Pulmonary Acute respiratory failure, Altitude sickness, Breath holding spells, Chronic obstructive pulmonary disease, Cough syncope, Decompression sickness, Drowning, Obstructive sleep apnea, Post lung transplantation, Pulmonary embolism, Pulmonary stenosis, Sarcoidosis, Sleep apnea, Tuberculosis
Renal/Electrolyte Acute renal failure, Amyloidosis, Chronic renal failure, Electrolyte disturbances, Hyperkalemia, Hypokalemia, Renal failure
Rheumatology/Immunology/Allergy Acute rheumatic fever, Ankylosing spondylitis, Churg-strauss syndrome, Neonatal lupus erythematosus, Reiter's syndrome, Relapsing polychondritis, Rheumatic fever, Rheumatic mitral valve disease, Rheumatoid arthritis, Sarcoidosis, Scleroderma, Sinus node fibrosis, Sjogren's syndrome, Systemic lupus erythematosus, Systemic sclerosis
Sexual No underlying causes
Trauma Cervical spine injury, Electric shock, Hypothermia, Pain, Septic shock, Severe brain injury, Spinal cord injury, acute, Starvation, Surgical trauma, Trauma
Urologic No underlying causes
Miscellaneous Aging, Defecation, Idiopathic

Causes Based on Pathophysiologic Origin of Impulse

From the Atria

Respiratory Sinus Arrhythmia

Sinus bradycardia

Sinoatrial block

Sinus arrest

Sick sinus syndrome

First degree AV block

Second degree AV block

Complete or third-degree AV block

Short PR interval

From the AV junction

Junctional bradycardia

From the Ventricles

Isorhythmic A-V dissociation

Idioventricular rhythm

Ventricular escape beat

Combined List of Causes in Alphabetical Order


  1. Boujnah MR, Jaafari A, Boukhris B, Boussabah I, Thameur M (2000). "[Sinoatrial block induced by therapeutic doses of diltiazem. Report of 3 cases]". Tunis Med. 78 (12): 735–7. PMID 11155380.
  2. 2.0 2.1 2.2 Malla RR, Sayami A (2007). "In hospital complications and mortality of patients of inferior wall myocardial infarction with right ventricular infarction". JNMA J Nepal Med Assoc. 46 (167): 99–102. PMID 18274563.
  3. 3.0 3.1 3.2 3.3 Van Bogaert, PP.; Pittoors, F. (2003). "Use-dependent blockade of cardiac pacemaker current (If) by cilobradine and zatebradine". Eur J Pharmacol. 478 (2–3): 161–71. PMID 14575801. Unknown parameter |month= ignored (help)
  4. 4.0 4.1 4.2 Bailey PL (1990). "Sinus arrest induced by trivial nasal stimulation during alfentanil-nitrous oxide anaesthesia". Br J Anaesth. 65 (5): 718–20. PMID 2248851.
  5. 5.0 5.1 5.2 5.3 5.4 5.5 5.6 5.7 5.8 Mills TA, Kawji MM, Cataldo VD, Pappas ND, O'Meallie LP, Breaux DM; et al. (2004). "Profound sinus bradycardia due to diltiazem, verapamil, and/or beta-adrenergic blocking drugs". J La State Med Soc. 156 (6): 327–31. PMID 15688675.
  6. 6.0 6.1 6.2 6.3 6.4 6.5 Lines D, Shipton EA (1991). "Severe bradycardia and sinus arrest after administration of vecuronium, fentanyl and halothane. A case report". S Afr Med J. 80 (4): 200–1. PMID 1678901.
  7. 7.0 7.1 7.2 Bonvini RF, Hendiri T, Anwar A (2006). "Sinus arrest and moderate hyperkalemia". Annales De Cardiologie Et D'angéiologie. 55 (3): 161–3. PMID 16792034. Unknown parameter |month= ignored (help)
  8. 8.0 8.1 8.2 Koay S, Dewan B (2013). "An unexpected Holter monitor result: multiple sinus arrests in a patient with lateral medullary syndrome". BMJ Case Rep. 2013. doi:10.1136/bcr-2012-007783. PMID 23386489.
  9. 9.0 9.1 van Cleef AN, Schuurman MJ, Busari JO (2011). "Third-degree atrioventricular block in an adolescent following acute alcohol intoxication". BMJ Case Rep. 2011. doi:10.1136/bcr.07.2011.4547. PMID 22679160.
  10. 10.0 10.1 Brvar M, Bunc M (2009). "High-degree atrioventricular block in acute ethanol poisoning: a case report". Cases J. 2: 8559. doi:10.4076/1757-1626-2-8559. PMC 2769457. PMID 19918387.
  11. 11.0 11.1 Wills BK, Liu JM, Wahl M (2010). "Third-degree AV block from extended-release diltiazem ingestion in a nine-month-old". J Emerg Med. 38 (3): 328–31. doi:10.1016/j.jemermed.2007.10.053. PMID 18403171. Unknown parameter |month= ignored (help)
  12. 12.0 12.1 Tian Z, Fang Q, Zhao DC; et al. (2010). "[The clinico-pathological manifestation of cardiac involvement in eosinophilic diseases]". Zhonghua Nei Ke Za Zhi (in Chinese). 49 (8): 684–7. PMID 20979789. Unknown parameter |month= ignored (help)
  13. Kertesz NJ, Fenrich AL, Friedman RA (1997). "Congenital complete atrioventricular block". Tex Heart Inst J. 24 (4): 301–7. PMC 325472. PMID 9456483.
  14. 14.0 14.1 Lionakis N, Moyssakis I, Gialafos E, Dalianis N, Votteas V (2008). "Aortic dissection and third-degree atrioventricular block in a patient with a hypertensive crisis". J Clin Hypertens (Greenwich). 10 (1): 69–72. PMID 18174773. Unknown parameter |month= ignored (help)
  15. 15.0 15.1 Amasyalı B, Barçın C, Kılıç A (2011). "[Supra-His complete atrioventricular block in a patient with subclinical hyperthyroidism]". Turk Kardiyol Dern Ars (in Turkish). 39 (8): 693–6. PMID 22257810. Unknown parameter |month= ignored (help)
  16. 16.0 16.1 Liu R, Qiao SB, Hu FH, Yang WX, Yuan JS (2012). "[Clinical features of five patients with delayed third degree atrioventricular block after ethanol septal ablation for hypertrophic obstructive cardiomyopathy]". Zhonghua Xin Xue Guan Bing Za Zhi (in Chinese). 40 (12): 1009–11. PMID 23363714. Unknown parameter |month= ignored (help)
  17. 17.0 17.1 Sykes JA, Lubega J, Ezetendu C, Verma R, O'Connor B, Kalyanaraman M (2011). "Asymptomatic complete atrioventricular block in a 13-year-old girl". Pediatr Emerg Care. 27 (11): 1081–3. doi:10.1097/PEC.0b013e3182360674. PMID 22068075. Unknown parameter |month= ignored (help)
  18. 18.0 18.1 18.2 "Idiopathic heart block: association with vitiligo, thyroid disease, pernicious anaemia, and diabetes mellitus". Retrieved 21 August 2013.
  19. 19.0 19.1 Bhattacharya IS, Dweck M, Francis M (2010). "Lyme carditis: a reversible cause of complete atrioventricular block". J R Coll Physicians Edinb. 40 (2): 121–2. doi:10.4997/JRCPE.2010.207. PMID 21125053. Unknown parameter |month= ignored (help)
  20. 20.0 20.1 Wagner V, Zima E, Gellér L, Merkely B (2010). "[Acute atrioventricular block in chronic Lyme disease]". Orv Hetil (in Hungarian). 151 (39): 1585–90. doi:10.1556/OH.2010.28965. PMID 20840915. Unknown parameter |month= ignored (help)
  21. 21.0 21.1 Semmler D, Blank R, Rupprecht H (2010). "Complete AV block in Lyme carditis: an important differential diagnosis". Clin Res Cardiol. 99 (8): 519–26. doi:10.1007/s00392-010-0152-8. PMID 20464556. Unknown parameter |month= ignored (help)
  22. 22.0 22.1 Facenda-Lorenzo M, Hernández-Afonso J, Rodríguez-Esteban M, de León-Hernández JC, Grillo-Pérez JJ (2012). "Cardiac Manifestations in Myotonic Dystrophy Type 1 Patients Followed Using a Standard Protocol in a Specialized Unit". Rev Esp Cardiol. doi:10.1016/j.recesp.2012.08.011. PMID 23194837. Unknown parameter |month= ignored (help)
  23. 23.0 23.1 Femenía F, Arce M, Arrieta M (2010). "[Systemic sclerosis complicated with syncope and complete AV block]". Medicina (B Aires) (in Spanish; Castilian). 70 (5): 442–4. PMID 20920962.
  24. 24.0 24.1 Maleki AR, Nikyar B, Hosseini SM (2012). "Third-Degree Heart Block in Thalassemia major: A Case Report". Iran J Pediatr. 22 (2): 260–4. PMC 3446065. PMID 23056897. Unknown parameter |month= ignored (help)
  25. 25.0 25.1 Thakar S, Chandra P, Pednekar M, Kabalkin C, Shani J (2012). "Complete heart block following a blow on the chest by a soccer ball: a rare manifestation of commotio cordis". Ann Noninvasive Electrocardiol. 17 (3): 280–2. doi:10.1111/j.1542-474X.2012.00518.x. PMID 22816548. Unknown parameter |month= ignored (help)
  26. 26.0 26.1 Portet N, Riu B, Bounes V, Minville V, Fourcade O (2012). "Left ventricular-right atrial communication with third-degree atrioventricular block after thoracic trauma". J Emerg Med. 43 (6): e385–8. doi:10.1016/j.jemermed.2010.11.059. PMID 21621364. Unknown parameter |month= ignored (help)
  27. 27.0 27.1 Frikha Z, Abid L, Abid D; et al. (2011). "Cardiac tamponade and paroxysmal third-degree atrioventricular block revealing a primary cardiac non-Hodgkin large B-cell lymphoma of the right ventricle: a case report". J Med Case Rep. 5: 433. doi:10.1186/1752-1947-5-433. PMC 3180417. PMID 21892927.
  28. 28.0 28.1 Houchaymi Z, Helou S, Ballout J (2010). "[Pericardial tamponade and third-degree atrioventricular block revealing a primary cardiac lymphoma]". Rev Med Interne (in French). 31 (11): e4–6. doi:10.1016/j.revmed.2010.01.014. PMID 20605278. Unknown parameter |month= ignored (help)
  29. 29.0 29.1 Perloff JK (1984). "Cardiac rhythm and conduction in Duchenne's muscular dystrophy: a prospective study of 20 patients". Journal of the American College of Cardiology. 3 (5): 1263–8. PMID 6707378. Unknown parameter |month= ignored (help)
  30. 30.0 30.1 Efthimiou J, McLelland J, Betteridge DJ (1986). "Short PR intervals and tachyarrhythmias in Fabry's disease". Postgraduate Medical Journal. 62 (726): 285–7. PMC 2418650. PMID 3086855. Unknown parameter |month= ignored (help)
  31. 31.0 31.1 Huang SK, Rosenberg MJ, Denes P (1984). "Short PR interval and narrow QRS complex associated with pheochromocytoma: electrophysiologic observations". Journal of the American College of Cardiology. 3 (3): 872–5. PMID 6693659. Unknown parameter |month= ignored (help)
  32. 32.0 32.1 Castellanos A, Castillo CA, Agha AS, Tessler M (1971). "His bundle electrograms in patients with short P-R intervals, narrow QRS complexes, and paroxysmal tachycardias". Circulation. 43 (5): 667–78. PMID 5578843. Unknown parameter |month= ignored (help)
  33. 33.0 33.1 McGregor A, Hurst E, Lord S, Jones G. "Bradycardia following retinoic acid differentiation syndrome in a patient with acute promyelocytic leukaemia". BMJ Case Rep. doi:10.1136/bcr.02.2012.5848. PMID 22778455.
  34. 34.0 34.1 Cannillo M, Frea S, Fornengo C, Toso E, Mercurio G, Battista S; et al. (2013). "Berberine behind the thriller of marked symptomatic bradycardia". World J Cardiol. 5 (7): 261–4. doi:10.4330/wjc.v5.i7.261. PMC 3722425. PMID 23888197.
  35. 35.0 35.1 Mehlsen J, Kaijer MN, Mehlsen AB (2008). "Autonomic and electrocardiographic changes in cardioinhibitory syncope". Europace. 10 (1): 91–5. doi:10.1093/europace/eum237. PMID 17971422.
  36. 36.0 36.1 Isbister GK (2002). "Delayed asystolic cardiac arrest after diltiazem overdose; resuscitation with high dose intravenous calcium". Emerg Med J. 19 (4): 355–7. PMC 1725910. PMID 12101159.
  37. 37.0 37.1 Brembilla-Perrot B, Muhanna I, Nippert M, Popovic B, Beurrier D, Houriez P; et al. (2005). "Paradoxical effect of isoprenaline infusion". Europace. 7 (6): 621–7. doi:10.1016/j.eupc.2005.06.012. PMID 16216767.
  38. 38.0 38.1 Guillén EL, Ruíz AM, Bugallo JB (1998). "Hypotension, bradycardia, and asystole after high-dose intravenous methylprednisolone in a monitored patient". Am J Kidney Dis. 32 (2): E4. PMID 10074612.
  39. 39.0 39.1 Landovitz RJ, Sax PE (1999). "Symptomatic junctional bradycardia after treatment with nelfinavir". Clin Infect Dis. 29 (2): 449–50. doi:10.1086/520237. PMID 10476763.
  40. 40.0 40.1 Zyśko D, Gajek J, Agrawal AK, Rudnicki J (2012). "[The relevance of junctional rhythm during neurocardiogenic reaction provoked by tilt testing]". Kardiol Pol. 70 (2): 148–55. PMID 22427080.
  41. 41.0 41.1 Cohen AS, Matharu MS, Goadsby PJ (2007). "Electrocardiographic abnormalities in patients with cluster headache on verapamil therapy". Neurology. 69 (7): 668–75. doi:10.1212/01.wnl.0000267319.18123.d3. PMID 17698788.

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