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April 1919


Author Affiliations

Mayo Clinic, Rochester, Minn.

Arch Intern Med (Chic). 1919;23(4):431-440. doi:10.1001/archinte.1919.00090210025003

Arborization block or impaired intraventricular conduction is dependent on graphic records for its recognition. It is now generally accepted to indicate disease of the subendocardial myocardium1 and evidences serious functional cardiac disturbance.2 The involvement occurs in the subendocardial or Purkinje plexus.

The deflections constituting the initial ventricular complex of the electocardiogram are termed Q, R, S, and indicate the passage of the electrical impulse through the main divisions of the auriculoventricular bundle and their arborizations. These deflections comprise a graphic record which is upright in all leads, is abruptly pointed, and has a narrow base. The normal base width does not exceed 0.10 second.3

Arborization block is recognized by abnormal deviations of the Q, R, S group. These are increased width, notching of the apex, and splintering of the ascending and descending limbs.

The bizarre complex of arborization block is probably due either to impulse transmission through circuitous and aberrant

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