MedGen

An electrocardiographic finding of a wide QRS complex with evidence of delayed conduction to the right ventricle, manifested by a widened initial portion of the QRS in V1 and V2, a widened S wave in V5, V6, I and aVL, and with QRS duration less than 120 ms. (CDISC) [from NCI]

An electrocardiographic finding of a wide QRS complex with evidence of delayed conduction to the right ventricle, manifested by a widened initial portion of the QRS in V1 and V2, a widened S wave in V5, V6, I and aVL, and with QRS duration greater than or equal to 120 ms. An RsR'' complex is typically present in leads V1 and V2. (CDISC) [from NCI]

Right bundle branch block (RBBB) represents an abnormality in the intraventricular electrical conduction system of the human heart, generating enlarged QRS and modified vectors on the electrocardiogram (ECG). Incomplete RBBB (IRBBB) is defined by (i) QRS duration between 110 and 120 ms in adults; (ii) rsr, rsR, or rSR in leads V1 or V2. The R or r deflection is usually wider than the initial R wave. In a minority of patients, a wide and often notched R wave pattern may be seen in leads V1 and/or V2; (iii) S wave of greater duration than R wave or greater than 40 ms in leads I and V6 in adults; and (iv) Normal R peak time in leads V5 and V6 but greater than 50 ms in lead V1. The first 3 criteria should be present to make the diagnosis. When a pure dominant R wave with or without a notch is present in V1, criterion 4 should be satisfied. [from HPO]