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Right Bundle Branch Block
- Criteria:
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AHA Criteria for RBBB (2009):
(MANDATORY #1-3. #4 is conditional)
1. QRS > 120 ms in adults (>100 ms in children 4-16yo, and > 90 ms <4yo
2. Leads V1 or V2:
- rsr' , rsR' , or rSR' pattern
- The R or r deflection is usually wider than the initial R wave.
- A wide and notched R wave pattern may be seen in lead V1 and/or V2.
3. Leads 1 and V6:
- S > R in duration OR >40 ms in leads I and V6 in adults.
4. R-wave Peak Time
(When a pure dominant R wave with or without a notch is present in V1)- Normal in V5/6, but >50 ms in V1
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- Reference: Surawicz (2009) "AHA/ACCF/HRS Recommendations for the Standardization and Interpretation of the Electrocardiogram", JACC, 53(11)
Incomplete Right Bundle Branch Block
- Criteria:
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AHA Criteria for Incomplete RBBB (2009):
1. Same criteria as RBBB except:
QRS 110-120ms (adults)
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- Reference: Surawicz (2009) "AHA/ACCF/HRS Recommendations for the Standardization and Interpretation of the Electrocardiogram", JACC, 53(11)
Left Bundle Branch Block
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AHA 2009 Guidelines for Left Bundle Branch Block:
1. QRS ≥ 120ms in adults (>100ms children 4-16, >90ms children <4yo)
2. Lateral Leads (I, aVL, V5, V6)
a.) Broad notched/slurred R-wave in LATERAL leads (I, aVL, V5, V6)
(Sometimes V5-6 can have RS pattern, due to displaced transition of QRS)
b.) Absent q-waves in LATERAL LEADS (I, V5, V6) (aVL may have q)
c.) R-wave peak-time WIDE in LATERAL > 60ms in V5-6 (Normal in V1-3)
3. ST and T-waves usually opposite direction of QRS
- Positive concordance can be normal (Positive T-wave in leads with upright QRS)
- NOTE: Negative concordance is abnormal. (Depressed ST or T-waves in leads with negative QRS)
4. Axis Deviation can be RIGHT, LEFT, or SUPERIOR
- NOTE: Usually lateral Q-waves represent fast (L-->R) septal depolarization (which is reversed in a LBBB)
- Reference: Surawicz (2009) "AHA/ACCF/HRS Recommendations for the Standardization and Interpretation of the Electrocardiogram", JACC, 53(11)
Incomplete Left Bundle Branch Block
- AHA Criteria for Incomlpete RBBB1. QRS 110 - 119ms (90 - 100ms in children 8-16yo, and 80-90ms in children <8yo)2. LVH Criteria Met3. R-wave Peak Time > 60ms4. No Q-waves in lateral leads: I, V5, and V6
- Reference: Surawicz (2009) "AHA/ACCF/HRS Recommendations for the Standardization and Interpretation of the Electrocardiogram", JACC, 53(11)
- Example of Incomplete LBBB:
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Left Anterior Fascicular Block
AHA 2009 Guidelines for Left Anterior Fascicular Block
1. Left Axis Deviation (-45° and -90°)
2. qR pattern in lead aVL.
3. R-peak time in lead aVL ≥45 ms.4. QRS < 120 ms.
Do not apply to patients with congenital heart disease with LAD since infancy.
- Reference: Surawicz (2009) "AHA/ACCF/HRS Recommendations for the Standardization and Interpretation of the Electrocardiogram", JACC, 53(11)
Left Posterior Fascicular Block
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Left Posterior Fascicular Block Criteria (AHA 2009)
1. Axis 90° to 180°
(Children up to 16 have more rightward axis, this criterion should only be applied to them when a distinct rightward change in axis is documented)
2. rS pattern in leads I and aVL.
3. qR pattern in leads III and aVF.
4. QRS duration < 120 ms
- Reference: Surawicz (2009) "AHA/ACCF/HRS Recommendations for the Standardization and Interpretation of the Electrocardiogram", JACC, 53(11)
Nonspecific Intraventricular Conduction Delay
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Nonspecific or Unspecified Intraventricular Conduction Disturbance DEFINITION:
- QRS > 110ms
- Does not meet criteria for LBBB or RBBB
OR - Limb leads have LBBB pattern and precordial limbs have RBBB pattern (or vice versa)
- Reference: Surawicz (2009) "AHA/ACCF/HRS Recommendations for the Standardization and Interpretation of the Electrocardiogram", JACC, 53(11)
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