First degree AV block causes
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First degree AV block Microchapters |
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Diagnosis |
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Treatment |
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Case Studies |
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First degree AV block causes On the Web |
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American Roentgen Ray Society Images of First degree AV block causes |
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Risk calculators and risk factors for First degree AV block 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]
Synonyms and keywords:; AV block, atrioventricular block, heart block
Overview
An atrioventricular block (or AV block) is a type of heart block involving an impairment of the conduction between the atria and ventricles of the heart.[1] It usually involves the atrioventricular node, but it can involve other structures too. AV block is categorized by degree and site of conduction block. In first-degree AV block, all atrial impulses are conducted to the ventricle. However, there is a delay within the AV node, resulting in a prolonged PR interval on ECG (>200 msec or >5 small blocks). In other words, first degree clock is a slowed conduction without loss of atrioventricular synchrony.
Causes
Life Threatening Causes
Life-threatening conditions can result in death or permanent disability within 24 hours if left untreated.
Common Causes
- Hyperkalemia
- Hyperthyroidism
- Increased vagal tone (e.g. sleep, athletes)
- Ischemic heart disease
- Medications ( e.g. adenosine, amiodarone, beta-blockers, diltiazem, procainamide, verapamil
Causes by Organ System
| Cardiovascular | AV nodal disease, Myocarditis, Acute myocardial infarction (especially acute inferior MI), Hypertension, Acute rheumatic fever, Dilated cardiomyopathy, HCM, Myocarditis, Valvular heart disease, Transposition of the great vessels, ASDs, Ebstein's anomaly, VSD, Tetralogy of Fallot, Endocardial cushion defect, Lev's disease |
| Chemical / poisoning | No underlying causes |
| Dermatologic | No underlying causes |
| Drug Side Effect | Calcium channel blockers, Beta-blockers, Digitalis, Cardiac glycosides, Cholinesterase inhibitors, Quinidine, Procainamide, Disopyramide, Flecainide, Encainide, Propafenone, Amiodarone, Sotalol, Dofetilide, Ibutilide, Magnesium |
| Ear Nose Throat | No underlying causes |
| Endocrine | No underlying causes |
| Environmental | No underlying causes |
| Gastroenterologic | Hemochromatosis |
| Genetic | No underlying causes |
| Hematologic | No underlying causes |
| Iatrogenic | No underlying causes |
| Infectious Disease | Acute rheumatic fever, Chagas disease, Diphtheria, Lyme disease, Myocarditis, Tuberculosis |
| Musculoskeletal / Ortho | Ankylosing spondylitis, Muscular dystrophy |
| Neurologic | No underlying causes |
| Nutritional / Metabolic | No underlying causes |
| Obstetric/Gynecologic | No underlying causes |
| Oncologic | No underlying causes |
| Opthalmologic | No underlying causes |
| Overdose / Toxicity | No underlying causes |
| Psychiatric | No underlying causes |
| Pulmonary | Sarcoidosis |
| Renal / Electrolyte | No underlying causes |
| Rheum / Immune / Allergy | Ankylosing spondylitis, Dermatomyositis, Scleroderma, SLE, Rheumatoid arthritis |
| Sexual | No underlying causes |
| Trauma | No underlying causes |
| Urologic | No underlying causes |
| Dental | No underlying causes |
| Miscellaneous | Amyloidosis, Enhanced vagal tone (for example in athletes), Normal variants |
Causes in Alphabetical Order
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