The Malposition of the Pacing Lead in the Left Ventricle through an Atrial Septal Defect.

A 54-year-old woman with a history of unknown childhood cardiac surgery underwent dual-chamber pacemaker implantation due to an advanced atrioventricular block in our center. One week later, we were asked to further evaluate tricuspid regurgitation via transthoracic echocardiography (TTE). The postoperative TTE demonstrated a left ventricular ejection fraction of 45%, as well as moderate mitral regurgitation, a severely dilated right atrium, a moderately dilated right ventricle, a dilated main pulmonary artery (38 mm), a mildly stenotic pulmonary artery (peak gradient=30 mmHg), and moderate-to-severe tricuspid regurgitation, with a right ventricular systolic pressure of 40 mmHg. The right atrial pacemaker lead was in its proper place, the ventricular lead in the right ventricle was undetectable due to very poor TTE views. Electrocardiography (ECG) showed a pacing rhythm with no other abnormalities (Figure 1).