Hidden in Plain Sight

Transvenous implantation of permanent pacemakers has been used to manage bradycardia and atrioventricular block since the 1960s. In the present case, a 65-year-old man with a transvenously implanted dual-chamber pacemaker arrived at a primary care clinic complaining of lightheadedness and “near blacking-out.” Occurrence of these presyncopal episodes had no relation to his level of activity (rest or exertion) or his position (upright or supine). No symptoms of nausea, shortness of breath, diaphoresis, or visual disturbances accompanied these episodes, and they resolved over the course of a few minutes. The patient stated that the presyncopal symptoms were similar to those he had experienced prior to his pacemaker placement 4 years ago for syncope and complete heart block.