An asymptomatic 25 year old male presents with an ECG pattern of bifasicular conduction block (left anterior hemi-block and right bundle branch block) after experiencing "extra/skipped beats".

The patient has no remarkable family or past medical history.

What are the potential causes of the bifasicular block in a male patient of this age and what tests should be done to differentiate these causes?

1 Answer 1


If the person is well, and investigations show no structural defects, then:

Early-onset cardiac conduction defects in the absence of structural heart disease should prompt consideration of CCD genetic testing, especially if a positive family history of conduction abnormalities and pacemaker implants is identified.

HRS/EHRA Expert Consensus Statement on the State of Genetic Testing for the Channelopathies and Cardiomyopathies

Some other causes not age specific some of which are listed here include ischemic heart disease, cardiomyopathies, hypertension, aortic stenosis, Lev’s disease, hyperkalemia, congenital heart disease, sarcoid cardiomyopathy, Chagas disease, and scleroderma.

  • Thanks that's helpful. What about when there is no family history?
    – Kenshin
    Commented Apr 12, 2016 at 8:12
  • Could be new mutation. But the point of genetic testing is to make sure no one else is affected Commented Apr 12, 2016 at 9:41
  • it could also be non-genetic, e.g. chagas disease, sarcoidosis maybe others?
    – Kenshin
    Commented Apr 12, 2016 at 11:23
  • Yes, but you said the patient was well. Commented Apr 12, 2016 at 20:54
  • Yes, but by well I meant asymptomatic. Chagas and primary sarcoidosis of the heart can often be asymptomatic.
    – Kenshin
    Commented Apr 13, 2016 at 7:45

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