Bradyarrhythmias: AV conduction disturbances.
When conduction block is located in the AV node, the QRS complex is narrow, and the escape rate is near normal. The patient is frequently minimally or not symptomatic. More often, however, the site of block is below the AV node, and the prognosis is much graver. It should be remembered that "high-grade" Type II block is not usually the result of a transient process, but rather of a chronic, progressive infranodal disease. This means that it is more likely to progress to complete heart block and require permanent pacing.
D000368:Aged; D001919:Bradycardia / Q000209:etiology* / Q000503:physiopathology; D004562:Electrocardiography; D006327:Heart Block / Q000145:classification / Q000150:complications* / Q000175:diagnosis; D006801:Humans