ECG Findings
• Wide QRS complex, at least 120 ms (three small blocks).
• QRS complex has sR’ or rsR’ in leads V1 and V2.
• Slurred S wave leads V6 and I.
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Important Points:
1. The signal exiting the AV node is carried rapidly to the LV through the intact left bundle, but is delayed into the right ventricle, where depolarization must propagate cell-to cell. Since the RV myocardial mass is much smaller than that of the LV, this delay in depolarization is best seen in the leads overlying the right ventricle, leads V1 and V2.
2. Acute right heart strain, as may occur with pulmonary embolism, may result in new onset right bundle branch block (RBBB).
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rsR’ pattern in V1 (arrowheads), with T wave downgoing (arrow). QRS duration greater than 120 ms (double arrow).
• Wide QRS complex, at least 120 ms (three small blocks).
• QRS complex has sR’ or rsR’ in leads V1 and V2.
• Slurred S wave leads V6 and I.
Important Points:
1. The signal exiting the AV node is carried rapidly to the LV through the intact left bundle, but is delayed into the right ventricle, where depolarization must propagate cell-to cell. Since the RV myocardial mass is much smaller than that of the LV, this delay in depolarization is best seen in the leads overlying the right ventricle, leads V1 and V2.
2. Acute right heart strain, as may occur with pulmonary embolism, may result in new onset right bundle branch block (RBBB).
