Abstract 16793: Association of Impairment of Myocardial Metabolism and Ventricular Arrhythmic Events in Patients With Hypertrophic Cardiomyopathy by Single Photon Emission Computed Tomography With A Solid-state Dedicated Cardiac Camera

Abstract

Background: Ventricular arrhythmic events have adverse implications for patients with hypertrophic cardiomyopathy (HCM). However, little has been reported on the relationship between myocardial metabolic abnormalities and ventricular arrhythmia. Iodine-123-beta-methyl iodophenyl-pentadecanoic acid (BMIPP) is used to assess myocardial metabolic abnormalities. A solid-state dedicated cardiac camera (D-SPECT) provides precise assessment of abnormal uptake and reduction of radiation dose in HCM by high sensitivity and high spatial resolution. Objective: The aim of this study was to evaluate the utility of BMIPP using D-SPECT for prediction of ventricular arrhythmic events in patients with HCM. Methods: We studied 125 consecutive HCM patients who underwent dual SPECT with D-SPECT using BMIPP and technetium-99m sestamibi (MIBI) or thallium-201 (TL). Reduced uptake on the BMIPP image compared with the MIBI / TL perfusion image was defined as perfusion-metabolic mismatch. In quantitative analysis, a polar map was divided into 17 segments and the score of each segment was derived from the average percent uptake. Mismatch scores (MS) were calculated from the differences between the BMIPP and MIBI / TL scores. Ventricular arrhythmic events were defined as ventricular tachycardia, appropriate ICD therapy and sudden cardiac death. Results: Patients with the obstructive type of HCM had a significantly higher MS than those with the non-obstructive type. Significant correlation between the MS and left ventricular mass (r = 0.28, p < 0.01) and maximal wall thickness (r = 0.27, p < 0.01) were observed. MS was significantly higher in patients with ventricular arrhythmic events than in those without events (p < 0.05). In ROC analysis, patients with a higher MS had significantly more arrhythmic events than those with a lower MS (cutoff value: 74.5, AUC: 0.644, p < 0.01). In multivariate analysis, the MS was identified as an independent factor associated with ventricular arrhythmic events (p < 0.01). Conclusions: Abnormal uptake of BMIPP in patients with HCM is associated with ventricular arrhythmic events. Dual SPECT with D-SPECT using BMIPP and MIBI / TL is a useful modality for risk stratification and may reveal the existence of substrate for ventricular arrhythmia.