Pediatric Second-Degree Atrioventricular Block Clinical Presentation

Updated: Sep 11, 2019
  • Author: M Silvana Horenstein, MD; Chief Editor: Syamasundar Rao Patnana, MD  more...
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History and Physical Examination

In patients with second-degree atrioventricular (AV) block, a detailed history is important to estimate the severity of the block, the need for further testing, and possible interventions. A familial history of rhythm disturbances should be sought.

Children in whom second-degree AV block is identified may present with a history of syncope (ie, fainting), presyncope (ie, dizziness), or palpitations, or it may simply be identified during a physical examination because of the irregular pulse.

In case of a syncopal episode, its severity should be assessed, including any associated injury or need for resuscitation. A detailed history of associated illnesses or symptoms should be obtained, as well as family history, maternal illness, travel history, drug ingestion, or toxic exposure.

High vagal autonomic tone may correlate with second-degree Mobitz I (Wenckebach) AV block, as well as possible vasodepressor reaction, as a cause for dizziness or syncope.

According to each subtype of second-degree AV block, the following clinical history may be elicited. In general, patients with Mobitz I (Wenckebach) AV block are asymptomatic. Sometimes, Mobitz I (Wenckebach) AV block is secondary to increased vagal tone, such as in athletes.

Patients with Mobitz II (non-Wenckebach) AV block may also be asymptomatic; however, they should be followed periodically because of the possibility of development of third-degree AV block (complete AV block) with cardiovascular syncope or Stokes-Adams attacks. These patients may also be at risk for sudden death.

Physical examination

The most prominent physical finding is usually that of an irregular pulse, typically with the impression of dropped or skipped beats. Secondary signs of heart failure or low cardiac output should be assessed, including blood pressure, apical impulse, hepatomegaly, and peripheral edema.