Nuclear Imaging Guidance for Ablation of Ventricular Arrhythmias.

Due to an increase in the number of patients with heart failure and ventricular arrhythmias, ventricular tachycardia ablation has a growing clinical role. Long-term success rates remain suboptimal and require creating a detailed electroanatomic map during the procedure to identify fibrotic areas responsible for arrhythmias. Nuclear imaging can identify areas of abnormal myocardial perfusion, metabolism, and innervation, which all may enhance our ability to identify ablation targets, thus decreasing procedure time and improving success rates. Myocardial scar, as assessed by single-photon emission computed tomography (SPECT) perfusion imaging, has been shown to correlate with abnormal areas found during electroanatomic mapping. Abnormal metabolism as identified by (18)fluorodeoxyglucose-positron-emission tomography (PET) imaging has been shown to predict successful ablation sites and help correct errors made in the creation of the electroanatomic map. Abnormal cardiac sympathetic innervation can be identified using the purpose (123)I-meta-iodobenzylguanidine SPECT imaging, which may help in identifying triggers that initiate ventricular tachycardia and also predict successful ablation sites within an otherwise normal myocardium. In conclusion, these imaging modalities can not only offer new insights into the pathophysiology of ventricular arrhythmias but also have the potential to improve outcomes from ventricular tachycardia ablation procedures.