A 52-year-old man with a dual-chamber pacemaker implanted because of intermittent, symptomatic, high-degree atrioventricular block presented with short episodes of dizziness and near fainting. A detailed history revealed that the symptoms occurred exclusively during self-prescribed therapy with a Zapper device. The Zapper, which is available worldwide, is a simple, battery-powered, direct-current-offset pulse generator with square-wave output at a constant frequency of 33.33 kHz ± 10%. These electronic pulse frequencies are applied to both hands. The Zapper is used regularly ‘to eliminate cancer, other chronic illnesses, self-diagnosed parasites and germs’.