title: Resting perfusion MPI-SPECT combined with cardiac 123I-mIBG sympathetic innervation imaging improves prediction of arrhythmic events in non-ischemic cardiomyopathy patients: sub-study from the ADMIRE-HF trial.
abstract: BACKGROUND
  Delayed Iodine-123 meta-iodobenzylguanidine heart/mediastinum (H/M) uptake ratio predicted arrhythmic events in patients with heart failure (HF) and significant left ventricular dysfunction in ADMIRE-HF. We tested the hypothesis that resting perfusion defects on MPI-SPECT, representing scar, would further risk stratify patients beyond H/M ratio in the prediction of ventricular arrhythmic events in both ischemic (ICM) and non-ischemic cardiomyopathy (NICM) patients.
  
  
  METHODS
  Patients from the ADMIRE-HF database were classified as ICM and NICM and were stratified by delayed H/M ratio (<1.6/≥1.6) and by summed rest score (SRS) (≤8/>8) on MPI-SPECT. The entire cohort was also classified as high risk (H/M <1.6, SRS >8) and low risk (H/M ≥1.6, SRS ≤8). Scores were from visual interpretation of individual and derived consensus (average) reads per ASNC guidelines.
  
  
  RESULTS
  There were 612 (66%) ICM and 317 (34%) NICM patients. ICM patients had higher mean SRS than NICM patients (25 ± 13 vs 12 ± 10). Sixty-three arrhythmic events occurred over a median follow-up of 17 months. SRS had incremental predictive value among NICM patients with low H/M ratio (<1.6). There was no risk stratification in patients with ICM. Multivariable analysis for NICM with H/M ratio <1.6 demonstrated SRS score >8 as the only independent predictor of arrhythmic events (hazard ratio 3.3, 95% CI 1.1-9.8, P = .03). Patients classified in high-risk subgroup had statistically significant increased risk of arrhythmic events (hazard ratio 2.080, 95% CI 1.112-3.894, P = .022). There was only one event in low-risk subgroup with a trend towards lower risk of arrhythmic events (P = .07).
  
  
  CONCLUSIONS
  Resting perfusion defects provide independent risk stratification in addition to Iodine-123 meta-iodobenzylguanidine sympathetic innervation imaging in predicting arrhythmic events in patients with NICM and HF. High and potentially low-risk groups for arrhythmic events can be identified based on the severity of resting perfusion defect score and H/M ratio.
authors.affiliation: Southcoast Health System, 75 Station Landing, Unit 407, Fall River, MA, 02155, USA, dr.nitesh.sood@gmail.com.
authors.forename: Nitesh
authors.initials: N
authors.lastname: Sood
authors.forename: Firas
authors.initials: F
authors.lastname: Al Badarin
authors.forename: Matthew
authors.initials: M
authors.lastname: Parker
authors.forename: Raja
authors.initials: R
authors.lastname: Pullatt
authors.forename: Arnold F
authors.initials: AF
authors.lastname: Jacobson
authors.forename: Timothy M
authors.initials: TM
authors.lastname: Bateman
authors.forename: Gary V
authors.initials: GV
authors.lastname: Heller
mesh_terms: D019797:3-Iodobenzylguanidine; D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D001145:Arrhythmias, Cardiac / Q000473:pathology; D009202:Cardiomyopathies / Q000000981:diagnostic imaging*; D002986:Clinical Trials as Topic; D015331:Cohort Studies; D005260:Female; D006321:Heart / Q000000981:diagnostic imaging*; D006801:Humans; D008297:Male; D008875:Middle Aged; D055414:Myocardial Perfusion Imaging / Q000379:methods*; D009206:Myocardium / Q000473:pathology*; D010477:Perfusion; D011446:Prospective Studies; D012044:Regression Analysis; D012306:Risk; D013564:Sympathetic Nervous System / Q000473:pathology; D013997:Time Factors; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*; D016896:Treatment Outcome; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging
chemical_list: D019797:3-Iodobenzylguanidine