1. INTRAVENTRICULAR CONDUCTION DISTURBANCES AHA/ACCF/HRS RECOMMENDATIONS FOR THE STANDARDIZATION AND INTERPRETATION OF IVCD JACC 2009 VOL 53

2. Normal QRS Duration  ↑with ↑ heart size  Wider - precordial > limb leads  Age- and gender-dependent  Children <4 yrs -QRS ≥90 ms prolonged  4 -16 yrs –QRS ≥ 100 ms prolonged  Adult males – N-QRS up to 110 ms J. Am. Coll. Cardiol. 2009;53;976-981;

3. Mean Frontal Plane Axis J. Am. Coll. Cardiol. 2009;53;976-981;

4. Shifts to the left with increasing age

5. Complete RBBB  QRS ≥120 ms (>16 yrs), >100 ms (4-16 yrs), >90 ms (<4 yrs)  rsr’, rsR’, or Rsr’ - V1 or V2. R’/r’ - Usually wider than initial R/r  S duration > R or >40 ms (I&V6)  Normal R peak time (V5 & V6) but >50 ms (V1)  First 3 should be present to make diagnosis o V1- pure dominant R wave ± notch → C riterion 4 should be satisfied J. Am. Coll. Cardiol. 2009;53;976-981;

6. Incomplete RBBB  QRS duration 110 -120 ms (adults), 90 - 100 ms (8 -16 yrs), 86 - 90 ms (<8 yrs)  Other criteria - Same as for complete RBBB.  Children –incomplete RBBB when terminal rightward deflection is less than 40 ms and greater than or equal to 20 ms  In the absence of heart disease –incomplete RBBB can occu rwhen V1 is placed higher or to the right from normal posistion J. Am. Coll. Cardiol. 2009;53;976-981;

7. Complete LBBB 1. QRS ≥120 ms (Adults),>100 ms (4-16), >90 ms ( <4) 2. Broad notched /slurred R wave - I, aVL, V5, V6 3. Absent q waves - I, V5, V6 (±q Avl) 4. R peak time > 60 ms in V5 & V6 but Normal in V1, V2,& V3 (when r is present) 5. ST & T - Usually opposite in direction to QRS 6. + T wave with upright QRS may be N (+ concordance) 7. ST depression and/or − T with − QRS (- concordance) -ABN J. Am. Coll. Cardiol. 2009;53;976-981;

8. Criteria for infarction in the presence of complete left bundle-branch block(GUSTO)  ST↑≥0.1 mV in leads with +QRS (concordant ST)  ST ↑≥ 0.5 mV in leads with −QRS (discordant ST)  ST ↓≥ 0.1 mV in V1-V3 (concordant ST)  Concordant ST changes -↑specificity but ↓ sensitivity  Discordant ST changes - ↓↓ specificity ↓↓ sensitivity  LBBB + concordant ST > 30-d mortality > LBBB + enzyme -- concordant ST changes J. Am. Coll. Cardiol. 2009;53;976-981;

9. Incomplete LBBB  1. QRS 110 -120ms (adults),90 - 100ms(8 -16), 80 - 90ms (<8)  2. Presence of LVH pattern  3. R peak time >60 ms in leads V4, V5, and V6  4. Absent q in I, V5, V6 J. Am. Coll. Cardiol. 2009;53;976-981;

10. Nonspecific/Unspecified Intraventricular Conduction Disturbance  QRS >110ms (adults), >90ms (8 -16), >80ms (<8) without criteria for RBBB or LBBB Also  RBBB criteria in precordial leads and LBBB criteria in limb leads, and vice versa J. Am. Coll. Cardiol. 2009;53;976-981;

11. Left Anterior Fascicular Block  1. Frontal plane axis -45°to -90°  2. qR pattern in aVL  3. R-peak time in aVL of ≥45 ms  4. QRS duration <120 ms These criteria do not apply to patients with CHD in whom LAD is present in infancy J. Am. Coll. Cardiol. 2009;53;976-981;

12. Left Posterior Fascicular Block  1. Frontal plane axis +90°to 180° (adults)  2. rS pattern in I and aVL  3. qR pattern in III and aVF  4. QRS <120 ms J. Am. Coll. Cardiol. 2009;53;976-981;

13. Terms Not Recommended  Mahaim-type preexcitation -because ∆ cannot be made with certainty with surface ECG  Atypical LBBB, bilateral bundle-branch block, bifascicular block, and trifascicular block -because of great variation in anatomy and pathology producing such patterns  Recommends that each conduction defect be described separately in terms of the structure or structures involved J. Am. Coll. Cardiol. 2009;53;976-981;

14. Peri-infarction block  abnormal Q wave generated by a MI in Inf/lat leads, terminal portion of QRS- wide and directed opposite to Q wave (i.e., a QR complex in the inferior or lateral leads) J. Am. Coll. Cardiol. 2009;53;976-981;