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| | __NOTOC__ |
| | {| class="infobox" style="float:right;" |
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| | |[[File:Siren.gif|30px|link= Bradycardia resident survival guide]]||<br>||<br> |
| | |[[Bradycardia resident survival guide|'''Resident'''<br>'''Survival'''<br>'''Guide''']] |
| | |} |
| | {| class="infobox" style="float:right;" |
| {{Infobox_Disease | | | {{Infobox_Disease | |
| Name = Bradycardia | | | Name = Bradycardia | |
| Image = Lead II rhythm generated sinus bradycardia.JPG| | | Image = Lead II rhythm generated sinus bradycardia.JPG| |
| ICD10 = {{ICD10|R|00|1|r|00}} |
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| ICD9 = {{ICD9|427.81}}, {{ICD9|659.7}}, {{ICD9|785.9}}, {{ICD9|779.81}} |
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| }} | | }} |
| | {{Bradycardia}} |
| | {{CMG}}; {{AE}} {{MUT}} {{Ibtisam}} |
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| {{SI}} | | {{SK}} Abnormally slow heartbeat, slow heartbeat |
| | | ==[[Bradycardia overview|Overview]]== |
| {{CMG}}; '''Associate Editor-In-Chief:''' {{MUT}}
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| ==Overview==
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| Bradycardia is defined as a resting [[heart rate]] of under 60 beats per minute.
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| ==Pathophysiology==
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| Pathologic bradycardias are caused by disorders of impulse generation (impaired automaticity at [[SA node]]), impulse conduction ([[heart block]]) or [[escape pacemaker]]s and rhythms. Bradycardia can be underlain by several causes, which are best divided into cardiac and non-cardiac causes. Non-cardiac causes are usually secondary, and can involve recreational drug use, [[endocrine]] disorders ([[hypothyroid]]); [[electrolyte]] imbalance ([[hyperkalemia]]); autonomic reflexes; situational factors (prolonged [[bed rest]]); infections [[lyme disease]], medications, and [[autoimmune|autoimmunity]] disorders. Cardiac causes include acute or chronic [[ischemic heart disease]], vascular [[heart disease]], [[valvular heart disease]], or degenerative primary electrical disease (fibrosis and calcification of the [[sinus node]] and [[conduction system]]).
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| ==Natural History, Complications, Prognosis==
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| Slower sinus rates are often very well tolerated. Asymptomatic resting bradycardias, particularly in trained athletes and young individuals are not pathological and doesn't not require treatment.
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| == Causes ==
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| It is difficult and sometimes impossible to assign a mechanism to any particular bradycardia. However, the underlying mechanism is not clinically relevant to treatment, which is the same in both cases of sick sinus syndrome: a permanent [[artificial pacemaker|pacemaker]].
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| There are generally two types of problems that result in bradycardias:
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| ===Disorders of the [[sinus node]] === | |
| * Impaired automaticity - Sinus node dysfunction/[[sick sinus syndrome]])
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| * Exit block - Impaired conduction of the impulse from the sinus node into the surrounding atrial tissue
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| ===Disorders of the [[atrioventricular node]] (AV node)===
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| * Atrioventricular conduction disturbances ([[First degree AV block|1<sup>o</sup> AV block]], [[Second degree AV block|2<sup>o</sup> type I AV block]], [[Second degree AV block|2<sup>o</sup> type II AV block]], [[Third degree AV block|3<sup>o</sup> AV block]]) may result from impaired conduction in the AV node, or anywhere below it, such as in the bundle of HIS.
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| ===Causes of Bradycardia By Organ System===
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| {|style="width:70%; height:100px" border="1"
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| |style="height:100px"; style="width:25%" border="1" bgcolor="LightSteelBlue" | '''Cardiovascular'''
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| |style="height:100px"; style="width:75%" border="1" bgcolor="Beige" |
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| [[Atrioventricular Block]],
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| [[Cardiac arrhythmia]],
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| [[Cardiac Dysrhythmias]],
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| [[Cardiomegaly]],
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| [[Right Bundle Branch Block]],
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| [[Second Degree AV Block]],
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| [[ST Elevation Myocardial Infarction Complications]],
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| [[Sinoatrial Block]],
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| [[Pulseless ventricular tachycardia]],
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| [[Sick sinus syndrome]],
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| |-
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| |-bgcolor="LightSteelBlue"
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| | '''Chemical / poisoning'''
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| |bgcolor="Beige"| No underlying causes
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| |-
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| |-bgcolor="LightSteelBlue"
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| | '''Dermatologic'''
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| |bgcolor="Beige"| No underlying causes
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| |-
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| |-bgcolor="LightSteelBlue"
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| | '''Drug Side Effect'''
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| |bgcolor="Beige"|
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| [[Aceclidine]],
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| [[Acepromazine]],
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| [[Acetylcholinesterase inhibitor]],
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| [[Adenosine]],
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| [[Amiodarone]],
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| [[Amodiaquine]],
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| [[Atenolol]],
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| [[Barbiturates]],
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| [[Beta-blockers]],
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| [[Bupivacaine]],
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| [[Calcium channel blocker]],
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| [[Clomipramine]],
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| [[Detomidine]],
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| [[Digitalis]],
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| [[Diltiazem]],
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| [[Diphenhydramine]],
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| [[Donepezil]],
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| [[Doxepin]],
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| [[Glyceryl trinitrate ]],
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| [[Hydrocodone]],
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| [[Ibuprofen]],
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| [[Isosorbide dinitrate]],
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| [[Ivabradine]],
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| [[Levobetaxolol]],
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| [[Levobupivacaine]],
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| [[Lidocaine]],
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| [[Lithium]],
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| [[Medetomidine]],
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| [[Mefloquine]],
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| [[Mepivacaine]],
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| [[Methacholine]],
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| [[Methoxamine]],
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| [[Methyldopa]],
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| [[Morphine]],
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| [[Moxonidine]],
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| [[Nadolol]],
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| [[Nalbuphine]],
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| [[Nalmefene]],
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| [[Opioid]],
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| [[Oxymorphone]],
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| [[Phenobarbital]],
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| [[Phenylephrine]],
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| [[Phenytoin]],
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| [[Pilocarpine]],
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| [[Propafenone]],
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| [[Propranolol]],
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| [[Quinidine]],
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| [[Reserpine]],
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| [[Ropivacaine]],
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| [[Sulpiride]],
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| [[Suxamethonium chloride]],
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| [[Tacrine]],
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| [[Timolol]],
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| [[Trazodone]],
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| [[Uncaria tomentosa]],
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| [[Xylazine]],
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| |-
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| |-bgcolor="LightSteelBlue"
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| | '''Ear Nose Throat'''
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| |bgcolor="Beige"| No underlying causes
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| |-
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| |-bgcolor="LightSteelBlue"
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| | '''Endocrine'''
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| |bgcolor="Beige"| [[Hypothyroidism]],
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| |-
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| |-bgcolor="LightSteelBlue"
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| | '''Environmental'''
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| |bgcolor="Beige"|
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| [[Grayanotoxin]],
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| [[Hellebore]],
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| [[Hypothermia]],
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| |-
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| |-bgcolor="LightSteelBlue"
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| | '''Gastroenterologic'''
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| |bgcolor="Beige"| No underlying causes
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| |-
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| |-bgcolor="LightSteelBlue"
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| | '''Genetic'''
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| |bgcolor="Beige"|
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| [[Congenital Long QT Syndrome]],
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| [[Catecholaminergic polymorphic ventricular tachycardia]],
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| [[Emery-Dreifuss muscular dystrophy]],
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| |-
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| |-bgcolor="LightSteelBlue"
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| | '''Hematologic'''
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| |bgcolor="Beige"| No underlying causes
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| |-
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| |-bgcolor="LightSteelBlue"
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| | '''Iatrogenic'''
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| |bgcolor="Beige"|
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| [[Enema]],
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| [[Gastric lavage]],
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| [[PCI Complications: Radiocontrast toxicity]],
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| [[Rapid sequence induction]],
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| |-
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| |-bgcolor="LightSteelBlue"
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| | '''Infectious Disease'''
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| |bgcolor="Beige"|
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| [[Chagas' disease]],
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| [[Hantavirus pulmonary syndrome]],
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| [[Legionella pneumonia and Mycoplasma pneumonia]],
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| [[Tularaemia]],
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| [[Colorado tick fever]],
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| [[Brucellosis]],
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| [[Trypanosoma cruzi]],
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| [[Typhoid fever]],
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| |-
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| |-bgcolor="LightSteelBlue"
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| | '''Musculoskeletal / Ortho'''
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| |bgcolor="Beige"|
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| [[Holt-Oram syndrome]],
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| [[Vertebral subluxation]],
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| |-
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| |-bgcolor="LightSteelBlue"
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| | '''Neurologic'''
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| |bgcolor="Beige"|
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| [[Vasovagal syncope]],
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| [[Vagal episode]],
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| [[Neurogenic shock]],
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| Subarachanoid hemorrhage,
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| [[Raised Intracranial pressure]],
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| [[Autonomic neuropathy]],
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| [[Cerebral hemorrhage]],
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| [[Cerebral venous sinus thrombosis]],
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| Cushing triad,
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| [[Cushing reaction]],
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| [[Cushing reflex]],
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| [[Neurocardiogenic Syncope]],
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| |-
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| |-bgcolor="LightSteelBlue"
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| | '''Nutritional / Metabolic'''
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| |bgcolor="Beige"|
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| [[Hypercalcemia]],
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| [[Hyperkalemia]],
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| [[Hypokalemia]],
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| [[Anorexia Nervosa]],
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| |-
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| |-bgcolor="LightSteelBlue"
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| | '''Obstetric/Gynecologic'''
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| |bgcolor="Beige"|
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| [[Fetal distress]],
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| [[Neonatal lupus erythematosus]],
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| [[Vasa previa]],
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| |-
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| |-bgcolor="LightSteelBlue"
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| | '''Oncologic'''
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| |bgcolor="Beige"| No underlying causes
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| |-
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| |-bgcolor="LightSteelBlue"
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| | '''Opthalmologic'''
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| |bgcolor="Beige"| [[Oculocardiac reflex]],
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| |-
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| |-bgcolor="LightSteelBlue"
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| | '''Overdose / Toxicity'''
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| |bgcolor="Beige"|
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| [[Gamma-Hydroxybutyric acid]],
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| [[Hydroxyethyl starch]]
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| [[Speedball (drug)]],
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| [[Theobromine poisoning]],
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| |-
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| |-bgcolor="LightSteelBlue"
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| | '''Psychiatric'''
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| |bgcolor="Beige"| [[Anorexia Nervosa]],
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| |-
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| |-bgcolor="LightSteelBlue"
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| | '''Pulmonary'''
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| |bgcolor="Beige"| [[Apnea of prematurity]],
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| |-
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| |-bgcolor="LightSteelBlue"
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| | '''Renal / Electrolyte'''
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| |bgcolor="Beige"| No underlying causes
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| |-
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| |-bgcolor="LightSteelBlue"
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| | '''Rheum / Immune / Allergy'''
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| |bgcolor="Beige"| No underlying causes
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| |-
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| |-bgcolor="LightSteelBlue"
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| | '''Sexual'''
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| |bgcolor="Beige"| No underlying causes
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| |-
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| |-bgcolor="LightSteelBlue"
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| | '''Trauma'''
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| |bgcolor="Beige"| No underlying causes
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| |-
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| |-bgcolor="LightSteelBlue"
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| | '''Urologic'''
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| |bgcolor="Beige"| No underlying causes
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| |-
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| |-bgcolor="LightSteelBlue"
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| | '''Miscellaneous'''
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| |bgcolor="Beige"|
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| [[Drowning]],
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| [[Mammalian diving reflex]],
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| |- | | ==[[Bradycardia historical perspective|Historical Perspective]]== |
| |}
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| ===Causes in Alphabetical Order=== | | ==[[Bradycardia classification|Classification]]== |
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| ==Epidemiology and Demographics== | | ==[[Bradycardia pathophysiology|Pathophysiology]]== |
| Bradycardia is more common in older patients.
| | ==[[Bradycardia causes|Causes]]== |
| | ==[[Bradycardia differential diagnosis|Differentiating Bradycardia from other Conditions]]== |
| | ==[[Bradycardia epidemiology and demographics|Epidemiology and Demographics]]== |
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| | ==[[Bradycardia risk factors|Risk Factors]]== |
| | ==[[Bradycardia screening|Screening]]== |
| | ==[[Bradycardia natural history, complications and prognosis|Natural History, Complications and Prognosis]]== |
| ==Diagnosis== | | ==Diagnosis== |
| Evaluation of bradycardia includes assessment of the heart rhythm, symptoms, medications, and associated medical conditions (reversible and irreversible). Symptomatic bradycardias are treated by removal of the underlying causes, medications (atropine) or insertion of a temporary or permanent pacemaker. The term ''relative bradycardia'' is used to explain a heart rate that, while not technically below 60 beats per minute, is considered too slow for the individual's current medical condition.
| | [[Bradycardia history and symptoms|History and Symptoms]] | [[Bradycardia physical examination|Physical Examination]] | [[Bradycardia laboratory findings|Laboratory Findings]] | [[Bradycardia electrocardiogram|Electrocardiogram]] | [[Bradycardia chest x ray|Chest X Ray]] | [[Bradycardia CT|CT]] | [[Bradycardia echocardiography or ultrasound|Echocardiography]] | [[Bradycardia other diagnostic studies|Other Diagnostic Studies]] |
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| ===Symptoms=== | | ==Treatment== |
| * [[Presyncope]]
| | [[Bradycardia medical therapy|Medical Therapy]] | [[Bradycardia surgery|Surgery]] | [[Bradycardia primary prevention|Primary Prevention]] | [[Bradycardia secondary prevention|Secondary Prevention]] | [[Bradycardia cost-effectiveness of therapy|Cost-Effectiveness of Therapy]] | [[Bradycardia future or investigational therapies|Future or Investigational Therapies]] |
| * [[Syncope]]
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| * [[Fatigue]]
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| * [[Angina]]
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| * Symptoms of [[congestive heart failure]]
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| ===Resting EKG=== | | ==Case Studies== |
| The [[heart rate]] is < 60 beats per minute.
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|
| <div align="left">
| | :[[Bradycardia case study one|Case #1]] |
| <gallery heights="175" widths="275">
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| Image:Lead II rhythm generated sinus bradycardia.JPG
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| </gallery>
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| </div>
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| ===24 Hour Ambulatory Electrocardiogram Monitoring=== | | ==Related Chapter== |
| The diagnosis is usually made with the help of a [[24-hour ambulatory electrocardiogram]] (ECG) or telemetry.
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| ==Treatment==
| | *[[AV Block]] |
| ===Urgent Treatment===
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| * Check drug list and remove drugs predisposing to bradycardia like [[beta blockers]], [[calcium channel blocker]], anti-arrhythmic drug. | |
| * Drug treatment for bradycardia is typically not indicated for patients who are asymptomatic.
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| * In symptomatic patients, underlying electrolyte or [[acid-base disorders]] or [[hypoxia]] should be corrected first.
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| * IV [[atropine]] may provide temporary improvement in symptomatic patients, although its use should be balanced by an appreciation of the increase in myocardial oxygen demand this agent causes. [[Atropine]] 0.5-1 mg IV or ET q3-5min up to 3 mg total (0.04 mg/kg)
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| ====Indications For a Temporary Pacemaker====
| | {{WikiDoc Help Menu}} |
| Advanced [[heart block]] such as [[complete heart block]] is an indication for a temporary [[pacemaker]] insertion.
| | {{WikiDoc Sources}} |
| | | [[CME Category::Cardiology]] |
| ===Chronic Management===
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| There are two main reasons for treating brandycardia:
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| #With bradycardia, the first is to address the associated symptoms, such as [[Fatigue (physical)|fatigue]], limitations on how much an individual can physically exert, [[fainting]] (syncope), [[dizziness]] or [[lightheadedness]], or other vague and non-specific symptoms.
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| #The other reason to treat bradycardia is if the person's ultimate outcome (prognosis) will be changed or impacted by the bradycardia.
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| Treatment in this vein depends on whether any symptoms are present, and what the underlying cause is.
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| Primary or [[idiopathic]] bradycardia is treated symptomatically if it is significant, and the underlying cause is treated if the bradycardia is secondary.
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| ==See also==
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| * [[AV Block]]
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| ==References==
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| {{reflist}} | |
| [[de:Bradykardie]] | |
| [[es:Bradicardia]]
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| [[fr:Bradycardie]]
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| [[it:Bradicardia]]
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| [[nl:Bradycardie]]
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| [[nn:Bradykardi]]
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| [[pl:Bradykardia]]
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| [[pt:Bradicardia]]
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| [[ru:Брадикардия]]
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| [[sk:Bradykardia]]
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| [[sv:Bradykardi]]
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| [[Category:Cardiology]] | | [[Category:Cardiology]] |
| [[Category:Symptoms]] | | [[Category:Medical signs]] |
| | [[Category:Signs and symptoms]] |
| [[Category:Emergency medicine]] | | [[Category:Emergency medicine]] |
| | | [[Category:Arrhythmia]] |
| {{WikiDoc Help Menu}}
| | [[Category:Electrophysiology]] |
| {{WikiDoc Sources}}
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