Second degree AV block causes

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Cafer Zorkun, M.D., Ph.D. [2] Mahmoud Sakr, M.D. [3]

Overview

Atrioventricular (AV) block is defined as an interruption in the transmission of an impulse, either transient or permanent, from the atria to the ventricles 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.

Common Causes

Causes by Organ System

Cardiovascular	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
Chemical / poisoning	No underlying causes
Dermatologic	No underlying causes
Drug Side Effect	Amiodarone, beta-blockers, digitalis, calcium channel blockers, cholinesterase inhibitors, disopyramide, dofetilide, dolasetron, donepezil, eslicarbazepine acetate, fesoterodine, fingolimod, flecainide, ibutilide, lacosamide, magnesium, paliperidone, procainamide, propafenone, propoxyphene, quinidine, sotalol, terodiline
Ear Nose Throat	No underlying causes
Endocrine	Hyperthyroidism, myxedema, thyrotoxic periodic paralysis
Environmental	Hypothermia
Gastroenterologic	Hemochromatosis
Genetic	Emery-Dreifuss muscular dystrophy, Fabry disease, glycogenosis type 2b, hereditary neuromuscular disease, Kearns-Sayre syndrome
Hematologic	Multiple myeloma
Iatrogenic	Post aortic valve replacement, post catheter ablation for arrhythmias, post closure of a ventricular septal defect, post mitral valve replacement
Infectious Disease	Acute rheumatic fever, Chagas disease, diphtheria, Lyme disease, myocarditis, neonatal lupus erythematosus, protozoal infection, sarcoidosis, SLE, tuberculosis
Musculoskeletal / Ortho	Ankylosing spondylitis, hereditary neuromuscular disease, Kearns-Sayre syndrome, mitochondrial genome inherited conditions, muscular dystrophy
Neurologic	No underlying causes
Nutritional / Metabolic	Fabry disease, glycogenosis type 2b
Obstetric/Gynecologic	No underlying causes
Oncologic	Multiple myeloma
Opthalmologic	No underlying causes
Overdose / Toxicity	No underlying causes
Psychiatric	No underlying causes
Pulmonary	Sarcoidosis
Renal / Electrolyte	Hyperkalemia, hypokalemia
Rheum / Immune / Allergy	Ankylosing spondylitis, dermatomyositis, rheumatoid arthritis, scleroderma, SLE
Sexual	No underlying causes
Trauma	No underlying causes
Urologic	No underlying causes
Dental	No underlying causes
Miscellaneous	Amyloidosis, degenerative diseases, Enhanced vagal tone, normal variants, pain, sleep , trauma

Causes in Alphabetical Order

References

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