Loss of Capture by Myocardial Ischemia: A Case Report

We report the case of a patient with pacemaker who presented chest pain during exercise followed by fainting. He has a history of arterial hypertension and diabetes. The initial examination was normal; the ventricular stimulation threshold was 1.125 volts (V) and cardiac enzymes were normal. Stress test has reproduced chest pain followed by loss of pacemaker capture and asystole (figure n◦1). Coronary angiography showed a tight stenosis of the proximal anterior interventricular artery dilated by a drug-eluting stent. The control of stress test was normal (figure n◦2). A stent thrombosis eight days later led to an acute coronary syndrome with recurrent syncope due to the loss of ventricular capture. The ventricular pacing threshold was then2.25 V. After revascularization and stabilization of the patient’s clinical status, this threshold returned to 1.125 V. This clinic case has confirmed that coronary artery disease could increase pacing threshold. It also highlights the usefulness of automatic capture algorithms in coronary patients. The stress test cannot only help to detect coronary artery disease but also allows the optimization of programming the pacemaker.