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| ==Overview== | | ==Overview== |
| An atrioventricular block (or AV block) is a type of [[heart block]] involving an impairment of the conduction between the [[atria]] and the [[ventricles]] of the heart. It usually involves the [[atrioventricular node]], but it can involve other structures too. AV block is categorized according to the degree and the site of conduction block. In first-degree AV block, all atrial impulses are conducted to the ventricles; however, there is a delay in conduction within the [[AV node]] resulting in a [[prolonged PR interval]] on [[ECG]] (>200 msec or >5 small blocks). In other words, first degree block is a slowed conduction without loss of atrioventricular synchrony.
| | Common causes of [[first-degree AV block]] include [[ischemic heart disease]], degenerative [[conduction]] system disease, [[congenital heart disease]], [[connective tissue disease]], [[inflammatory diseases]], [[medications]] and [[healthy individuals] in the absence of acute [[cardiovascular]] disease. |
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| ==Causes== | | ==Causes== |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Cafer Zorkun, M.D., Ph.D. [2]; Raviteja Guddeti, M.B.B.S. [3]
Overview
Common causes of first-degree AV block include ischemic heart disease, degenerative conduction system disease, congenital heart disease, connective tissue disease, inflammatory diseases, medications and [[healthy individuals] in the absence of acute cardiovascular disease.
Causes
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
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Acute myocardial infarction, acute rheumatic fever, ASD, dilated cardiomyopathy, Ebstein's anomaly, hypersensitive carotid sinus syndrome, hypertension, hypertrophic cardiomyopathy, Lev's disease, myocardial bridging, myocarditis, post aortic valve replacement, post catheter ablation for arrhythmias, post closure of a ventricular septal defect, post mitral valve replacement, tetralogy of Fallot, endocardial cushion defect, transposition of the great vessels, valvular heart disease, VSD
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| Chemical / poisoning
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No underlying causes
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| Dermatologic
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No underlying causes
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| Drug Side Effect
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Amiodarone, beta-blockers, digitalis, calcium channel blockers, cholinesterase inhibitors, disopyramide, dofetilide, dolasetron, donepezil, eslicarbazepine acetate, fesoterodine, fingolimod, flecainide, ibutilide, lacosamide, magnesium, paliperidone, pramipexole, procainamide, propafenone, propoxyphene, quinidine, sotalol, terodiline
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| Ear Nose Throat
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No underlying causes
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| Endocrine
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Hyperthyroidism, myxedema, thyrotoxic periodic paralysis
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| Environmental
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Hypothermia
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| Gastroenterologic
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Hemochromatosis
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| Genetic
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Emery-Dreifuss muscular dystrophy, Fabry disease, glycogenosis type 2b, hereditary neuromuscular disease, Kearns-Sayre syndrome
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| Hematologic
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Multiple myeloma
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| Iatrogenic
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Post aortic valve replacement, post catheter ablation for arrhythmias, post closure of a ventricular septal defect, post mitral valve replacement
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| Infectious Disease
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Acute rheumatic fever, Chagas disease, diphtheria, Lyme disease, myocarditis, neonatal lupus erythematosus, protozoal infection, sarcoidosis, SLE, tuberculosis
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| Musculoskeletal / Ortho
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Ankylosing spondylitis, hereditary neuromuscular disease, Kearns-Sayre syndrome, mitochondrial genome inherited conditions, muscular dystrophy
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| Neurologic
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No underlying causes
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| Nutritional / Metabolic
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Fabry disease, glycogenosis type 2b
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| Obstetric/Gynecologic
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No underlying causes
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| Oncologic
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Multiple myeloma
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| Opthalmologic
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No underlying causes
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| Overdose / Toxicity
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No underlying causes
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| Psychiatric
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No underlying causes
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| Pulmonary
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Sarcoidosis
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| Renal / Electrolyte
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Hyperkalemia, hypokalemia
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| Rheum / Immune / Allergy
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Ankylosing spondylitis, dermatomyositis, rheumatoid arthritis, scleroderma, SLE
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| Sexual
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No underlying causes
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| Trauma
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No underlying causes
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| Urologic
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No underlying causes
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| Dental
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No underlying causes
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| Miscellaneous
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Amyloidosis, degenerative diseases, enhanced vagal tone, normal variants
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Causes in Alphabetical Order
References
Template:WikiDoc Sources