Single-photon cardiac imaging in patients with cardiac implantable electrical devices.

Nuclear imaging techniques like single-photon emission computed tomography (SPECT) and radionuclide angiography have wide applications in patients receiving a cardiac implantable electrical device (CIED), who cannot usually undergo cardiac magnetic resonance. Our aim was to provide an update of single-photon imaging clinical applications, with a specific focus on CIED recipients. SPECT imaging is commonly used in CIED patients to assess myocardial perfusion, but it can also be used to evaluate myocardial viability, which is an important predictor of LV function improvement by cardiac resynchronization therapy (CRT). Radionuclide angiography has shown higher temporal resolution and reproducibility than SPECT in the evaluation of cardiac function and dyssynchrony. Left ventricular dyssynchrony as assessed by radionuclide angiography with phase analysis may be reliably used for CRT patient selection and evaluation of CRT response. SPECT imaging with meta-iodo-benzyl-guanidine allows for cardiac sympathetic innervation examination, which may be used for prognostic stratification of heart failure patients and prediction of ventricular tachyarrhythmias. Finally, promising results in CIED infection diagnosis have been shown by SPECT with radiolabeled autologous white blood cells.