How are cases in which third-degree atrioventricular (AV) block results from a calcium channel blocker managed?

Updated: Jul 05, 2018
  • Author: Akanksha Agrawal, MBBS; Chief Editor: Jeffrey N Rottman, MD  more...
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Answer

Cases in which complete heart block results from a calcium channel blocker should be managed in much the same fashion as cases involving other causes of third-degree block (eg, pacemaker), but affected patients should also receive appropriate treatment for toxicity from calcium channel blockers. This therapy includes the administration of intravenous (IV) fluids, calcium, glucagons, vasopressors, and high-dose insulin (hyperinsulinemic euglycemia [HIE] therapy). (See Toxicity, Calcium Channel Blocker.)

Overdoses of beta-blockers are managed similarly to overdoses of calcium channel blockers, although HIE therapy for beta-blocker overdoses is less well established. (See Toxicity, Beta-blocker.)

Medical treatment of complete heart block is limited to patients with conduction disease in the AVN. Patients with block at the AVN level, in the absence of ischemia, can benefit from sympathomimetic agents or vagolytic agents.

Initial efforts should focus on assessing the need for temporary pacing and initiating the pacing. Except in the case of AV block caused by medications that can be withdrawn or infections that can be treated, most patients with acquired complete heart block will require a permanent pacemaker or an implantable cardioverter defibrillator (ICD).

A study by Zhao et al in 38 patients who underwent dual-chamber pacemaker implantation for third-degree AV block found that compared with those who underwent implantation in the right ventricular apex, patients whose pacemaker was implanted in the right ventricular outflow tract exhibited better results with regard to systolic function and systolic dyssynchronization, at 12-month follow-up. [19]


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