First degree AV block causes

Common causes of first-degree AV block include ischemic heart disease, congenital heart disease, electrolyte abnormalities (particularly hypokalemia and hypomagnesemia), inflammation, infections (endocarditis, rheumatic fever, Chagas disease, Lyme disease, diphtheria), drugs (antiarrhythmic Ia, Ic, II, III, IV and digoxin, β-blockers, calcium channel blockers ), infiltrative diseases (sarcoidosis), collagen vascular diseases (SLE, rheumatoid arthritis, scleroderma), idiopathic degenerative diseases (Lenegre and Lev diseases) and neuromuscular disorders and increased vagal tone in younger patients.

Life-threatening causes include conditions which may result in death or permanent disability within 24 hours if left untreated.

• Acute myocardial infarction
• Acute rheumatic fever
• Bacterial endocarditis
• Myocarditis

• Hyperkalemia
• Hyperthyroidism
• Hypothyroidism
• Increased vagal tone (e.g. sleep, athletes)
• Ischemic heart disease
• Medications ( e.g. adenosine, amiodarone, beta-blockers, diltiazem, procainamide, verapamil)

Template:WikiDoc Sources