View source for Second degree AV block causes

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{{Second degree AV block}}
{{CMG}}; {{AE}} {{CZ}}; {{MS}}

==Overview==
Atrioventricular (AV) block is defined as an interruption in the transmission of an impulse, either transient or permanent, from the [[atria]] to the [[ventricle]]s due to an anatomic or functional impairment in the conduction system.  In second degree AV block, some atrial impulses fail to reach the ventricles.  Wenckebach described progressive delay between atrial and ventricular contraction and the eventual failure of an atrial beat to reach the ventricles.  Mobitz subsequently divided second degree AV block into two subtypes, as determined by the findings on the [[electrocardiogram]].  In Mobitz type I AV block, progressive [[PR interval]] prolongation precedes a non-conducted [[P wave]].  While in Mobitz type II AV block, the PR interval remains unchanged prior to a P wave that suddenly fails to conduct to the ventricles.

==Causes==
===Life Threatening Causes===
Life-threatening conditions  can result in death or permanent disability within 24 hours if left untreated<ref name="pmid29493981">{{cite journal |vauthors=Mangi MA, Jones WM, Napier L |title= |journal= |volume= |issue= |pages= |date= |pmid=29493981 |doi= |url=}}</ref>.
* [[Acute myocardial infarction]]<ref name="pmid30227965">{{cite journal |vauthors=Misumida N, Ogunbayo GO, Kim SM, Abdel-Latif A, Ziada KM, Elayi CS |title=Frequency and Significance of High-Degree Atrioventricular Block and Sinoatrial Node Dysfunction in Patients With Non-ST-Elevation Myocardial Infarction |journal=Am. J. Cardiol. |volume=122 |issue=10 |pages=1598–1603 |date=November 2018 |pmid=30227965 |doi=10.1016/j.amjcard.2018.08.001 |url=}}</ref><ref name="pmid23224264">{{cite journal |vauthors=Barold SS, Herweg B |title=Second-degree atrioventricular block revisited |journal=Herzschrittmacherther Elektrophysiol |volume=23 |issue=4 |pages=296–304 |date=December 2012 |pmid=23224264 |doi=10.1007/s00399-012-0240-8 |url=}}</ref>
* [[Acute rheumatic fever]]
* [[Bacterial endocarditis]]
* [[Myocarditis]]
* [[hypothermia|Severe hypothermia]]

===Common Causes=== 
* [[Acute rheumatic fever]]
* [[Bacterial endocarditis]]<ref name="pmid27585419">{{cite journal |vauthors=Kamatani T, Akizuki A, Kondo S, Shirota T |title=Second-Degree Atrioventricular Block Occurring After Tooth Extraction |journal=Anesth Prog |volume=63 |issue=3 |pages=156–9 |date=Fall 2016 |pmid=27585419 |pmc=5011958 |doi=10.2344/15-00042.1 |url=}}</ref>
* [[aortic stenosis|Calcific aortic stenosis]]
* [[Digoxin]]
* [[Dilated cardiomyopathy]]
* [[Diltiazem]]
* [[Vasovagal syncope#Cardioinhibitory Response|Enhanced vagal tone]]
* [[HCM]]
* [[Hypertension]]
* [[Iatrogenic]] after surgical correction of [[VSD]], [[tetralogy of Fallot]], and [[endocardial cushion defect]]
* [[ST elevation MI|Inferior ST elevation MI]]
* [[mitral valve sclerosis|Massive calcification of the mitral annulus]]
* [[Myocarditis]]
* [[PR interval|Normal variants]]<ref name="pmid8445186">{{cite journal |vauthors=Wogan JM, Lowenstein SR, Gordon GS |title=Second-degree atrioventricular block: Mobitz type II |journal=J Emerg Med |volume=11 |issue=1 |pages=47–54 |date=1993 |pmid=8445186 |doi=10.1016/0736-4679(93)90009-v |url=}}</ref>
* [[chest trauma|Penetrating and non-penetrating trauma of the chest]]
* [[Lev's disease|Sclerodegenerative disease of the electrical conduction system]]
* [[Verapamil]]
* [[Beta blocker|β blockers]]

===Causes by Organ System===
{|style="width:80%; height:100px" border="1"
|style="height:100px"; style="width:25%" border="1" bgcolor="LightSteelBlue" | '''Cardiovascular'''
|style="height:100px"; style="width:75%" border="1" bgcolor="Beige" | [[Acute myocardial infarction]], [[acute rheumatic fever]], [[ASD]], [[dilated cardiomyopathy]], [[Ebstein's anomaly]], [[Carotid sinus hypersensitivity|hypersensitive carotid sinus syndrome]], [[hypertension]], [[hypertrophic cardiomyopathy]], [[Lev's disease]], [[myocardial bridging]], [[myocarditis]], [[PR interval|normal variants]], [[Aortic valve replacement|post aortic valve  replacement]], [[catheter ablation|post catheter ablation for arrhythmias]], [[ventricular septal defect surgery|post closure of a ventricular septal defect]], [[mitral valve replacement|post mitral valve replacement]], [[tetralogy of Fallot]], [[endocardial cushion defect]], [[transposition of the great vessels]], [[valvular heart disease]], [[VSD]]
|-
|-bgcolor="LightSteelBlue"
| '''Chemical / poisoning'''
|bgcolor="Beige"| No underlying causes
|-
|-bgcolor="LightSteelBlue"
| '''Dermatologic'''
|bgcolor="Beige"| No underlying causes
|-
|-bgcolor="LightSteelBlue"
| '''Drug Side Effect'''
|bgcolor="Beige"| [[Amiodarone]], [[beta-blockers]], [[digitalis]], [[calcium channel blockers]], [[cholinesterase inhibitor|cholinesterase inhibitors]], [[disopyramide]], [[dofetilide]], [[dolasetron]], [[donepezil]], [[eslicarbazepine acetate]], [[fesoterodine]], [[fingolimod]], [[flecainide]], [[ibutilide]], [[lacosamide]], [[magnesium]], [[paliperidone]], [[pramipexole]], [[procainamide]], [[propafenone]], [[propoxyphene]], [[quinidine]], [[sotalol]], [[terodiline]]
|-
|-bgcolor="LightSteelBlue"
| '''Ear Nose Throat'''
|bgcolor="Beige"| No underlying causes
|- 
|-bgcolor="LightSteelBlue"
| '''Endocrine'''
|bgcolor="Beige"| [[Hyperthyroidism]], [[myxedema]], [[periodic  paralysis|thyrotoxic periodic paralysis]]
|- 
|-bgcolor="LightSteelBlue"
| '''Environmental'''
|bgcolor="Beige"| [[Hypothermia]]
|-
|-bgcolor="LightSteelBlue"
| '''Gastroenterologic'''
|bgcolor="Beige"| [[Hemochromatosis]]
|-
|-bgcolor="LightSteelBlue"
| '''Genetic'''
|bgcolor="Beige"| [[Emery-Dreifuss muscular dystrophy]], [[Fabry disease]], [[glycogenosis type 2b]], [[Neuromuscular disease|hereditary neuromuscular disease]], [[Kearns-Sayre syndrome]]
|-
|-bgcolor="LightSteelBlue"
| '''Hematologic'''
|bgcolor="Beige"| [[Multiple myeloma]] [[Lymphoma]]<ref name="pmid27200273">{{cite journal |vauthors=Menicagli F, Lanza A, Sbrocca F, Baldi A, Spugnini EP |title=A case of advanced second-degree atrioventricular block in a ferret secondary to lymphoma |journal=Open Vet J |volume=6 |issue=1 |pages=68–70 |date=2016 |pmid=27200273 |pmc=4833871 |doi=10.4314/ovj.v6i1.10 |url=}}</ref>
|-
|-bgcolor="LightSteelBlue"
| '''Iatrogenic'''
|bgcolor="Beige"| [[aortic valve  replacement|Post aortic valve  replacement]], [[catheter ablation|post catheter ablation for  arrhythmias]], [[ventricular septal defect surgery|post closure of a  ventricular septal defect]], [[mitral valve  replacement|post mitral valve  replacement]]
|-
|-bgcolor="LightSteelBlue"
| '''Infectious Disease'''
|bgcolor="Beige"| [[Acute rheumatic fever]], [[Chagas disease]], [[diphtheria]], [[Lyme disease]], [[myocarditis]], [[neonatal lupus erythematosus]], [[protozoa|protozoal infection]], [[sarcoidosis]], [[SLE]], [[tuberculosis]]
|-
|-bgcolor="LightSteelBlue"
| '''Musculoskeletal / Ortho'''
|bgcolor="Beige"| [[Ankylosing spondylitis]], [[Neuromuscular disease|hereditary neuromuscular disease]], [[Kearns-Sayre syndrome]], [[mitochondrial DNA|mitochondrial genome inherited conditions]], [[muscular dystrophy]]
|-
|-bgcolor="LightSteelBlue"
| '''Neurologic'''
|bgcolor="Beige"| [[Vasovagal syncope#Cardioinhibitory Response|Enhanced vagal tone]]
|-
|-bgcolor="LightSteelBlue"
| '''Nutritional / Metabolic'''
|bgcolor="Beige"| [[Fabry disease]], [[glycogenosis type 2b]]
|-
|-bgcolor="LightSteelBlue"
| '''Obstetric/Gynecologic'''
|bgcolor="Beige"| No underlying causes
|-
|-bgcolor="LightSteelBlue"
| '''Oncologic'''
|bgcolor="Beige"| [[Multiple myeloma]]
|-
|-bgcolor="LightSteelBlue"
| '''Opthalmologic'''
|bgcolor="Beige"| No underlying causes
|-
|-bgcolor="LightSteelBlue"
| '''Overdose / Toxicity'''
|bgcolor="Beige"| No underlying causes
|-
|-bgcolor="LightSteelBlue"
| '''Psychiatric'''
|bgcolor="Beige"| No underlying causes
|-
|-bgcolor="LightSteelBlue"
| '''Pulmonary'''
|bgcolor="Beige"| [[Sarcoidosis]]
|-
|-bgcolor="LightSteelBlue"
| '''Renal / Electrolyte'''
|bgcolor="Beige"| [[Hyperkalemia]], [[hypokalemia]]

|-bgcolor="LightSteelBlue"
| '''Rheum / Immune / Allergy'''
|bgcolor="Beige"| [[Ankylosing spondylitis]], [[dermatomyositis]], [[rheumatoid arthritis]], [[scleroderma]], [[SLE]]
|-
|-bgcolor="LightSteelBlue"
| '''Sexual'''
|bgcolor="Beige"| No underlying causes
|-
|-bgcolor="LightSteelBlue"
| '''Trauma'''
|bgcolor="Beige"| No underlying causes
|-
|-bgcolor="LightSteelBlue"
| '''Urologic'''
|bgcolor="Beige"| No underlying causes
|-
|-bgcolor="LightSteelBlue"
| '''Dental'''
|bgcolor="Beige"| No underlying causes
|-
|-bgcolor="LightSteelBlue"
| '''Miscellaneous'''
|bgcolor="Beige"|  [[Amyloidosis]], [[degenerative diseases]]
|-
|}

===Causes in Alphabetical Order===
{{col-begin|width=80%}}
{{col-break|width=33%}}
* [[Acute  myocardial infarction]]
* [[Acute rheumatic fever]]
* [[Amyloidosis]]
* [[Ankylosing spondylitis]]
* [[ASD]]
* [[Bacterial endocarditis]]
* [[Beta-blockers]]
* [[Calcific aortic stenosis]]
* [[Calcium channel blockers]]
* [[Cardiac glycosides]]
* [[Cardiac tumors]]
* [[Chagas disease]]
* [[Cholinesterase inhibitors]]
* [[Clonidine]]
* [[Degenerative diseases]]
* [[Dermatomyositis]]
* [[Digitalis]]
* [[Digoxin]]
* [[Dilated cardiomyopathy]]
* [[Diltiazem]]
* [[Diphtheria]]
* [[Disopyramide]]
* [[Dolasetron]]
* [[Donepezil]]
* [[Ebstein's anomaly]]
* [[Electrolyte disturbances]]
* [[Emery-Dreifuss muscular dystrophy]]
* [[Endocarditis]]
* [[vagus nerve|Enhanced vagal tone in athletes]] 
{{col-break|width=33%}}
* [[Eslicarbazepine acetate]]
* [[Fabry disease]]
* [[Fesoterodine]]
* [[Fingolimod]]
* [[Glycogenosis type 2b]]
* [[HCM]]
* [[Neuromuscular disease|Hereditary neuromuscular disease]]
* [[Hodgkin lymphoma]]
* [[Hyperkalaemia]]
* [[Carotid sinus hypersensitivity|Hypersensitive carotid  sinus syndrome]]
* [[Hyperthyroidism]]
* [[Hypokalaemia]]
* [[Hypothermia]]
* [[Ibutilide]]
* [[Ischemic heart disease]]
* [[Kearns-Sayre syndrome]]
* [[Labetalol]]
* [[Lacosamide]]
* [[Lanatoside C]]
* [[Lenegre's disease]]
* [[Lev's disease]]
* [[Lyme disease]]
* [[Mitochondrial DNA|Mitochondrial genome inherited conditions]]
* [[Multiple myeloma]]
* [[Muscular dystrophy]]
* [[Myocardial bridging]]
* [[Myocarditis]]
* [[Myotonic dystrophy]]
* [[Myxedema]]
{{col-break|width=33%}}
* [[Neonatal lupus erythematosus]]
* [[prolonged PR interval|Normal variants of PR prolongation]]
* [[Paliperidone]]
* [[aortic valve  replacement|Post aortic valve replacement]]
* [[catheter ablation|Post catheter ablation for  arrhythmias]]
* [[Ventricular septal defect surgery|Post closure of a  ventricular septal defect]]
* [[mitral valve  replacement|Post mitral valve  replacement]]
* [[Procainamide]]
* [[Propoxyphene]]
* [[Propranolol]]
* [[Protozoa|Protozoal infection]]
* [[Quinidine]]
* [[Quinine]]
* [[Rheumatic fever|Rheumatic mitral valve disease]]
* [[Sarcoidosis]]
* [[SLE]]
* [[Systemic sclerosis]]
* [[Terodiline]]
* [[Tetralogy of Fallot]]
* [[periodic  paralysis|Thyrotoxic periodic paralysis]]
* [[Tolterodine]]
* [[Transposition of the great vessels]]
* [[vagus nerve|Vagal maneuvers]]
* [[Valsalva maneuvers]]
* [[Valvular heart disease]]
* [[Verapamil]]
* [[VSD]]
* [[sex linkage|X-linked inherited  conditions]]
{{col-end}}

==References==
{{Reflist|2}}

[[Category:Cardiology]]
[[Category:Up-To-Date]]
[[Category:Up-To-Date cardiology]]
[[Category:Arrhythmia]]
[[Category:Electrophysiology]]
[[Category:Disease]]

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