Medication Summary
In general, patients with second-degree atrioventricular (AV) block with symptomatic bradycardia may be medicated with intravenous isoproterenol or atropine acutely. However, these agents must be administered in a hospital setting with cardiac monitoring available. Patients with Mobitz I (Wenckebach) AV block secondary to increased vagal tone may respond to theophylline, glycopyrrolate, or scopolamine. Pacemaker therapy is required when medications fail to control symptoms.
Beta-adrenergic agonists
Class Summary
Isoproterenol has beta1-adrenergic and beta2-adrenergic receptor activity. It binds beta receptors of the heart, smooth muscle of bronchi, skeletal muscle, vasculature, and alimentary tract. Isoproterenol has positive inotropic and chronotropic actions.
Isoproterenol (Isuprel)
Isoproterenol is usually given as a continuous intravenous infusion for rate support. It is usually administered as a temporizing measure, initiated during the organization of temporary or permanent pacing system placement for symptomatic patients with bradycardia from heart block or sinus node disease.
Anticholinergics
Class Summary
The goal of anticholinergic therapy is to improve AV node conduction by reducing vagal tone via the muscarinic receptor blockade. This is effective only if the site of a block is within the AV node. Anticholinergic therapy is ineffective for patients with infranodal block.
Atropine
Atropine is administered to increase heart rate through vagolytic effects, causing an increase in cardiac output.
Berdajs D, Schurr UP, Wagner A, Seifert B, Turina MI, Genoni M. Incidence and pathophysiology of atrioventricular block following mitral valve replacement and ring annuloplasty. Eur J Cardiothorac Surg. May 14 2008;[Medline].
Suda K, Raboisson MJ, Piette E, Dahdah NS, Miro J. Reversible atrioventricular block associated with closure of atrial septal defects using the Amplatzer device. J Am Coll Cardiol. May 5 2004;43(9):1677-82. [Medline].
Khongphatthallayothin A, Chotivitayatarakorn P, Somchit S. Morbitz type I second degree AV block during recovery from dengue hemorrhagic fever. Southeast Asian J Trop Med Public Health. Dec 2000;31(4):642-5. [Medline].
Costedoat-Chalumeau N, Georgin-Lavialle S, Amoura Z, Piette JC. Anti-SSA/Ro and anti-SSB/La antibody-mediated congenital heart block. Lupus. 2005;14(9):660-4. [Medline].
Chang YL, Hsieh PC, Chang SD. Perinatal outcome of fetus with isolated congenital second degree atrioventricular block without maternal anti-SSA/Ro-SSB/La antibodies. Eur J Obstet Gynecol Reprod Biol. Oct 1 2005;122(2):167-71. [Medline].
Vantyghem MC, Pigny P, Maurage CA, Rouaix-Emery N, Stojkovic T, Cuisset JM, et al. Patients with familial partial lipodystrophy of the Dunnigan type due to a LMNA R482W mutation show muscular and cardiac abnormalities. J Clin Endocrinol Metab. Nov 2004;89(11):5337-46. [Medline].
Payne CE, Usher BW. Atrioventicular block in familial amyloidosis; revisiting an old debate. J S C Med Assoc. Jun 2007;103(5):119-22. [Medline].
Cui G, Kobashigawa J, Margarian A. Cause of atrioventricular block in patients after heart transplantation. Transplantation. Jul 15 2003;76(1):137-42. [Medline].
Niwa K, Warita N, Sunami Y. Prevalence of arrhythmias and conduction disturbances in large population-based samples of children. Cardiol Young. Feb 2004;14(1):68-74. [Medline].
Massin MM, Bourguignont A, Gérard P. Study of cardiac rate and rhythm patterns in ambulatory and hospitalized children. Cardiology. 2005;103(4):174-9. [Medline].
Zhao H, Cuneo BF, Strasburger JF, Huhta JC, Gotteiner NL, Wakai RT. Electrophysiological characteristics of fetal atrioventricular block. J Am Coll Cardiol. Jan 1 2008;51(1):77-84. [Medline].
Nagashima M, Matsushima M, Ogawa A, et al. Cardiac arrhythmias in healthy children revealed by 24-hour ambulatory ECG monitoring. Pediatr Cardiol. 1987;8(2):103-8. [Medline].
Fernandez P, Corfield VA, Brink PA. Progressive familial heart block type II (PFHBII): a clinical profile from 1977 to 2003. Cardiovasc J S Afr. May-Jun 2004;15(3):129-32. [Medline].
Horigome H, Nagashima M, Sumitomo N, et al. Clinical characteristics and genetic background of congenital long-QT syndrome diagnosed in fetal, neonatal, and infantile life: a nationwide questionnaire survey in Japan. Circ Arrhythm Electrophysiol. Feb 1 2010;3(1):10-7. [Medline].
Ruffatti A, Milanesi O, Chiandetti L, et al. A combination therapy to treat second-degree anti-ro/la-related congenital heart block. a strategy to avoid stable third-degree heart block?. Lupus. Dec 20 2011;[Medline].
Wilkoff BL, Auricchio A, Brugada J, et al. HRS/EHRA Expert Consensus on the Monitoring of Cardiovascular Implantable Electronic Devices (CIEDs): description of techniques, indications, personnel, frequency and ethical considerations: developed in partnership with the Heart Rhythm Society (HRS) and the European Heart Rhythm Association (EHRA); and in collaboration with the American College of Cardiology (ACC), the American Heart Association (AHA), the European Society of Cardiology (ESC), the Heart Failure Association of ESC (HFA), and the Heart Failure Society of America (HFSA). Endorsed by the Heart Rhythm Society, the European Heart Rhythm Association (a registered branch of the ESC), the American College of Cardiology, the American Heart Association. Europace. Jun 2008;10(6):707-25. [Medline].

