Conduction disturbances and pacemaker

The most frequent clinical conditions complicated by bradyarrhythmias or atrioventricular (AV) blocks seen in an emergency setting are degeneration of the conduction system, acute myocardial infarction, drug toxicity, and hyperkalaemia. Pacemaker malfunction is another cause of potentially life-threatening bradyarrhythmias. The presence of signs/symptoms of hypoperfusion and the localization of the block condition the therapeutic approach. Treatment of bradyarrhythmias and AV blocks in a critical care setting may be preventive or therapeutic. A preventive approach is necessary when the risk of a sudden block with an inadequate ventricular escape rhythm is present, but the patient is asymptomatic. Symptomatic patients require immediate treatment. If the block is located at His bundle level or at bundle branch level atropine may be ineffective and may even worsen the degree of block. If drug administration is ineffective, transvenous temporary pacing is indicated. Transcutaneous cardiac pacing is another temporary method of pacing indicated in various critical clinical settings.