Assessing arrhythmic risk with ¹²³I-mIBG and analogous tracers: Image interpretation from a different viewpoint

Excerpt

In patients with chronic heart failure (HF), the most catastrophic outcome is sudden cardiac death (SCD), particularly in a patient who is otherwise doing relatively well. SCD accounts for up to 50% of HF deaths.1 While there are a variety of etiologies, it is most often a ventricular tachycardia progressing to ventricular fibrillation (VT/VF). Numerous large prospective multicenter studies have demonstrated improved patient survival with primary preventive use of an implantable cardioverter defibrillator (ICD) that in guidelines has been assigned a Class IA indication for “primary prevention of SCD to reduce total mortality in selected patients with nonischemic [dilated cardiomyopathy] or ischemic heart disease at least 40 days post-MI with [a left ventricular rejection fraction] (LVEF) of 35% or less and NYHA class II or III symptoms on [guideline directed medical therapy], who have a reasonable expectation of meaningful survival for more than 1 year.”2 Yet, in spite of such a strong recommendation, it is widely acknowledged that basing primary prevention ICD use on a LVEF threshold, particularly 35%, is not well supported by clinical experience,3 or when findings of the randomized studies upon which guidelines are based are examined more closely.4 With current practice, >80% of primary prevention patients do not use their ICD over a duration of as long as 8 years, with the device costing as high as $235,000 per year of life saved, and with a significant potential for serious device complications.5 It is clear that a better approach to selecting HF patients for primary prevention ICD implantation is needed. …