FIGURE 8-10.
Third-degree (complete) AV block.
Note the P waves (arrows) “marching through.”
Left Anterior Fascicular Block (LAFB)
HIGH-YIELD FACTS
ECG: Left axis deviation (LAD). QRS duration 0.10 to 0.12 second. Peak of terminal R in aVL precedes peak of terminal R in aVR. Deep S waves in II, III, and aVF. Lead I R wave > leads II or III.
Left Posterior Fascicular Block (LPFB)
Cardiovascular Emergencies
ECG: R axis deviation QRS duration 0.10 to 0.12 second Small R and deep S in lead I Lead III R wave > lead II Small Q in II, III, and aVF
Left Bundle Branch Block (LBBB)
Presence of new LBBB may indicate AMI.
Conduction blocked before anterior and posterior fascicles split (Figure 8-11).
FIGURE 8-11.
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Left bundle branch block.