Pediatric Left Bundle Branch Block Clinical Presentation

Updated: May 25, 2018
  • Author: Bahram Kakavand, MD, FACC, FHRS, CEPS-PC; Chief Editor: Stuart Berger, MD  more...
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History and Physical Examination


Important points to cover when one obtains a history from a child with left bundle branch block (LBBB) include known congenital heart disease, previous cardiac surgery, or both. Questions regarding fatigue, exercise intolerance, presyncope, and syncope may further indicate the clinical significance of the LBBB.

Note that in athletes with asymptomatic LBBB, this is not associated with normal exercise physiology and is more likely indicating an underlying cardiac pathology. [11]

Physical examination

Upon physical examination, auscultatory findings in patients with LBBB include an absent or diminished first heart sound and reversed splitting of the second heart sound. That is, the second heart sound is split in expiration and single in inspiration.