Figure 14

Atrial fibrillation complicated by repetitive aberrant ventricular conduction. The impulses that end the shortest ventricular cycles (0.28 to 0.32s) are anomalous, widened complexes. These almost certainly represent a right bundle branch block type of ventricular aberration rather than ventricular ectopy. In other words, the widened QRS complexes are due to different routes of conduction in the ventricles, but actually arose from impulses in the atria as did the predominant, narrower, downwardly directed QRS's, rather than arising from irritated foci in the ventricles (ventricular ectopy).

Myerburg, R.J., M.D., Castellanos, A., M.D., Kessler, K.M., M.D., Recognition, Clinical Assessment and Management of Arrhythmias and Conduction Disturbances, Hurst's The Heart, 8th ed, p 726.