Position of Subcutaneous Implantable Cardioverter-Defibrillators and Possible Interference on Myocardial Perfusion Imaging

Abstract

Implanted cardioverter-defibrillators can prevent sudden cardiac death in at-risk patients. In comparison with conventional transvenous systems, entirely subcutaneous implantable cardioverter-defibrillators have produced similar reductions in the rate of sudden cardiac death but with fewer sequelae. An infrequently reported drawback of subcutaneous devices, however, is the potential for generating attenuation artifact during nuclear myocardial perfusion imaging. We had concerns about potential attenuation artifact in a 65-year-old man with coronary artery disease but found that having positioned the pulse generator in the midaxillary zone avoided problems.

Keywords: Arrhythmias, cardiac/therapy; artifacts; coronary artery disease/diagnostic imaging; death, sudden, cardiac/prevention & control; defibrillators, implantable; equipment safety; myocardial perfusion imaging/methods.

Fig. 1.

Computed tomographic fusion image shows our patient's pulse generator along the midaxillary line (arrows). Most of the myocardium is spared from potential attenuation artifact.

Fig. 2.

Illustrative chest radiograph (lateral view) in a different patient shows a pulse generator implanted too far anteriorly, so that it obscures the inferolateral wall.

Fig. 3.

Illustrative chest radiograph (lateral view) in a third patient shows optimal positioning of the pulse generator, with the heart borders minimally obscured. Shown are the cardiac silhouette (oval), midaxillary borderline (dashed line), subcutaneous implantable cardioverter-defibrillator lead (arrow), and shock coil (arrowhead). The double arrow spans the length of the pulse generator and its center intersects the midaxillary line.

Fig. 4.

Raw computed tomogram in our patient (79° left anterior oblique projection) shows the myocardial borders (large circle) and the external dimensions of the pulse generator (small circle).

Fig. 5.

Raw computed tomogram in our patient (82° left anterior oblique projection) clearly shows the eclipse of the posterolateral wall, along with the myocardial borders (large circle) and the external dimensions of the pulse generator (small circle).