Pediatric Third-Degree Acquired Atrioventricular Block Treatment & Management

Updated: Dec 23, 2019
  • Author: Charles I Berul, MD; Chief Editor: Howard S Weber, MD, FSCAI  more...
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Approach Considerations

Treatment is focused on restoring atrioventricular (AV) sequential activation and/or maintaining a heart rate tolerated by the patient, which is assessed by the absence of symptoms. [30]  Other measures include resuscitation, diagnostic testing, treating potential reversible causes, monitoring for progression, and assessing whether definitive pacemaker placement is required. [31]

Asymptomatic patients require no immediate pacemaker treatment, although these individuals should be closely monitored. If the escape rhythm slows, they may become symptomatic and require permanent pacemaker therapy. Indications for permanent pacing are outlined in detail in the American College of Cardiology Foundation, American Heart Association Task Force on Practice Guidelines, and the Heart Rhythm Society.(ACCF/AHA/HRS) expert consensus documents. [32, 33, 34, 35]

Recognizing Lyme disease is important, because appropriate antibiotic therapy for 10-20 days with tetracyclines, erythromycin, intravenous penicillin, or ceftriaxone can often revert the complete AV block (in addition to preventing rheumatologic and neurologic symptoms).


Temporary Cardiac Pacing

In symptomatic patients with atrioventricular (AV) block, perform cardiac compressions, and administer catecholaminergic agonists (to accelerate the escape rhythm) while preparing for temporary cardiac pacing. Permanent cardiac pacing will be required if the AV block does not resolve.

Acquired AV block (AVB) from myocarditis, Lyme disease, and surgically induced trauma caused by adjacent tissue edema in patients with structurally normal hearts is usually transient and may not require therapy or may require only temporary pacing. However, in 40-55% of postsurgical patients, complete AV block persists beyond 7-14 days, and pacemaker therapy is indicated. [36]

In postoperative patients with intermittent AV block, externalized temporary cardiac pacing wires that can be attached to an external temporary pulse generator set at a predetermined rate to maintain adequate cardiac output is typically required.

In postoperative patients with persistent complete AV block lasting more than 7 days within or below the bundle of His, permanent pacemaker therapy is currently indicated. [37]

If the escape rhythm is less than 60 bpm in infants or 45 bpm in adolescents, permanent pacemaker therapy may be indicated to prevent symptoms, congestive heart failure, ventricular arrhythmias, or sudden cardiac death.

Temporary external cardiac pacing can also be performed in emergency situations, but it is not as effective as transvenous pacing and can also be uncomfortable if the patient is conscious.


Permanent Pacing

Patients with postoperative complete atrioventricular (AV) block (AVB) and those with Kearns-Sayre syndrome require prophylactic pacemaker therapy before symptoms develop because of the high risk for sudden death from asystole (> 60% in some series).

Regardless of symptoms or underlying escape rate, patients with postoperative complete AV block should always receive a permanent pacemaker system if the AV block persists more than 8-14 days and if no contraindications to pacemaker implantation are noted. [37] However, the overall prevalence of postsurgical complete AV block lasting over 10 days has been reduced to 5%. Most patients with postoperative complete AV block recover AV conduction within the first 7-10 postoperative days. These pediatric patients do not require a permanent pacemaker if conduction has fully recovered.

Stanner et al evaluated the midterm results of epicardial pacemakers implanted in a retrospective review of 71 infants who underwent implantation between 2000 and 2017. They concluded epicardial pacemakers are safe for infants at least 5 years. However, battery depletion is a frequent occurrence due to stimulation at higher heart rates in infancy. [38]

Prophylactic pacemaker therapy is indicated for any patient with complete AV block with a wide QRS escape rhythm. [37] Pacing is also indicated in patients with complete AV block who have exercise intolerance or other symptoms of chronotropic incompetence.

Dual-chamber pacemakers are currently preferred for patients who require life-time pacing. The preferred pacemaker modalities in most centers include the single-chamber pacing and dual-chamber sensing (VDD) [39] and the dual-chamber pacing and sensing (DDD). [40] These allow physiologic ventricular tracking of the atrial rate.

The long-term effects of asynchronous cardiac activation induced by right ventricular (RV) apical pacing have been described in patients with congenital complete AV block and normal cardiac anatomy. [41] These effects included deleterious left ventricular (LV) remodeling, LV dilatation and asymmetric LV hypertrophy. [42] However, pacing from the RV outflow tract decreases or slows adverse cardiac remodeling [43] and improves hemodynamics. [44]

Cardiac resynchronization pacing (biventricular pacing) may reduce or reverse the effects of left ventricular dysfunction induced by chronic right ventricular apical pacing. [45]