LAUSR

In extreme circumstances, pulsatile facial redness may result from the same pathophysiology that produces cannon A waves. An 89-year-old man presented with a complaint of decreased exertion tolerance. The electrocardiogram revealed complete atrioventricular block with a ventricular escape at 34 beats/ min. Echocardiography demonstrated normal ventricular function and no significant valvulopathy. On physical examination, there was pulsatile neck fullness and facial flushing, both coinciding with ventricular systole (see Videos 1 and 2). Cannon Awaves are seen during arrhythmias in which the atria and ventricles sometimes contract simultaneously, including complete heart block, ventricular tachycardia, and atrioventricular nodal reentry. The pressure generated by atrial contraction against a closed tricuspid valve is transmitted to the jugular veins, resulting in pulsatile fullness in the neck. This patient demonstrated a particularly pronounced example of this physiology, resulting in not only pulsatile neck fullness but also easily detectable cyclic changes in the color of his skin. These changes were especially obvious when the patient’s P waves coincided exactly with QRS complexes. The remarkable oscillation of facial color may have been particularly evident owing to his fair baseline complexion. After pacemaker implantation, cannon A waves were resolved.