Acute hyperkalemia and failure of pacemaker stimulus.

Acute hyperkalemia may induce well-known serious cardiac arrhythmia. However, ventricular aberration including concealed conduction may also occur. We report the case of a 35-year-old woman who had a previous history of late-operated ventricular septal defect communication and DDD pacemaker was admitted for dyspnea. During hospitalization, an acute hyperkalemia induced sinoatrial block despite correct pacemaker programming. Sodium bicarbonate allowed to restore sinus rhythm. Our report highlights that acute hyperkalemia may increase thresholds of pacemaker stimulus and physicians should be aware that complete block of conduction may occur despite correct pacemaker programming.