Dextrocardia, Left Bundle Branch Block and Atrial Fibrillation

ECGs from a patient with dextrocardia and left bundle branch block, recorded with standard lead positions and then with right sided leads to correct for the reversal of the depolarization vector.

Images in this series

Dextrocardia, Left Bundle Branch Block and Atrial Fibrillation

by: Kathryn E. Lichtenfels, B.S.N., R.N.; Joe B. Calkins, Jr., M.D.

The ECG in Image 1 is recorded with the leads in the standard positions. In the presence of dextrocardia, ventricular depolarization is directed to the patient’s right side. As a result, right axis deviation is present and low R wave amplitude and deep S waves are recorded in the anterior, anterolateral and lateral leads. QRS prolongation (130 msec) is present as a result of left bundle branch block (LBBB). The rhythm is atrial fibrillation.

Dextrocardia, Left Bundle Branch Block and Atrial Fibrillation

by: Kathryn E. Lichtenfels, B.S.N., R.N.; Joe B. Calkins, Jr., M.D.

The ECG in Image 2 is recorded using right chest leads, which results in the usual upright, wide (132 msec) and monophasic QRS complexes of LBBB in leads V4-6. Because the limb leads are in the standard positions, right axis deviation is present due to the rightward direction of ventricular depolarization. Secondary ST and T wave abnormality due to LBBB is present in leads V5 and V6. The rhythm is atrial fibrillation.

Dextrocardia, Left Bundle Branch Block and Atrial Fibrillation

by: Kathryn E. Lichtenfels, B.S.N., R.N.; Joe B. Calkins, Jr., M.D.

Image 3 is recorded with all leads reversed. The rightward ventricular depolarization is recorded as positive deflections in the anterolateral and lateral leads, resulting in the usual pattern of LBBB. Secondary ST and T wave abnormality due to LBBB is present in leads V5, V6, I and aVL. The rhythm is atrial fibrillation.