Myocardial perfusion imaging in a case of cardiac strangulation: A novel approach to detect pacemaker-induced ischemia

Abstract

Cardiac strangulation is a rare phenomenon in children following epicardial pacemaker implantation, caused by compression of the heart and great vessels by the epicardial pacemaker wires. We report a rare case of cardiac strangulation presenting after 8 years of epicardial pacemaker implantation. On routine follow-up, computed tomography angiography showed significant extrinsic compression of the mid-left anterior descending (LAD) artery by the epicardial pacing wire. She was referred to our department for myocardial perfusion imaging (MPI), which showed significant inducible ischemia in the LAD territory. Following this, she underwent a successful pacemaker reimplantation. MPI can, thus, act as a good tool to assess the functional significance of the compression caused by strangulation of the heart by pacemaker leads in asymptomatic patients.

Keywords: Congenital heart block; myocardial ischemia; pacing in children.

Figure 1

Computed tomography angiography: (a) Three-dimensional reconstructed image showing status postcardiac pacemaker implantation with epicardial pacemaker wires encircling the heart and causing significant extrinsic compression of the mid left anterior descending; and (b) axial section showing right ventricular lateral wall and left ventricular apical and lateral wall aneurysms

Figure 2

(a) STEP10 images of myocardial perfusion imaging – short, vertical, and long axis showing mild-to-moderate hypoperfusion in apex (green arrows), apical anterior (red arrows), apical inferior (blue errors), and anterolateral wall (yellow areas) on stress images, which show partial improvement on resting images, (b) polar map showing summed difference score (summed stress score – summed rest score) of 6

Figure 3

(a) Preoperative chest X-ray (CXR) shows looping of pacemaker wires around the heart and (b) postoperative CXR shows successful pacemaker change