title: A prospective pilot study to evaluate the relationship between acute change in left ventricular synchrony after cardiac resynchronization therapy and patient outcome using a single-injection gated SPECT protocol.
abstract: BACKGROUND
  There are ongoing efforts to optimize patient selection criteria for cardiac resynchronization therapy (CRT). In this regard, the relationship between acute change in left ventricular synchrony (LV) after CRT and patient outcome remains undefined.
  
  
  RESULTS
  A novel protocol was designed to evaluate acute change in left LV synchrony after CRT using phase analysis of standard gated single-photon emission computed tomography (SPECT) myocardial perfusion imaging with a single injection of radiotracer and prospectively applied to 44 patients undergoing CRT. Immediately after CRT, 18 (41%), 11 (25%), and 15 (34%) patients had an improvement, no change, or a worsening in LV synchrony. An algorithm incorporating the presence of baseline dyssynchrony, myocardial scar burden, and lead concordance predicted acute improvement or no change in LV synchrony with 72% sensitivity, 93% specificity, 96% positive predictive value, and 64% negative predictive value and had 96% negative predictive value for acute deterioration in synchrony. Over a follow-up period of 9.6 ± 6.8 months, patients who had an acute deterioration in synchrony after CRT had a higher composite event rate of death, heart failure hospitalizations, appropriate defibrillator discharges, and CRT device deactivation for worsening heart failure symptoms, compared with patients who had an improvement or no change [hazard ratio, 4.6 (1.3 to 16.0); log rank test; P=0.003].
  
  
  CONCLUSIONS
  In this single-center pilot study, phase analysis of gated SPECT was successfully used to predict acute change in LV synchrony and patient outcome after CRT.
authors.affiliation: Cardiovascular Institute, University of Pittsburgh Medical Center, Pittsburgh, PA, USA.
authors.forename: Mati
authors.initials: M
authors.lastname: Friehling
authors.forename: Ji
authors.initials: J
authors.lastname: Chen
authors.forename: Samir
authors.initials: S
authors.lastname: Saba
authors.forename: Raveen
authors.initials: R
authors.lastname: Bazaz
authors.forename: David
authors.initials: D
authors.lastname: Schwartzman
authors.forename: Evan C
authors.initials: EC
authors.lastname: Adelstein
authors.forename: Ernest
authors.initials: E
authors.lastname: Garcia
authors.forename: William
authors.initials: W
authors.lastname: Follansbee
authors.forename: Prem
authors.initials: P
authors.lastname: Soman
mesh_terms: D000368:Aged; D058406:Cardiac Resynchronization Therapy / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006333:Heart Failure / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000628:therapy; D006801:Humans; D007275:Injections, Intravenous; D008297:Male; D010865:Pilot Projects; D011446:Prospective Studies; D019275:Radiopharmaceuticals / Q000008:administration & dosage*; D020127:Recovery of Function / Q000502:physiology*; D012720:Severity of Illness Index; D013318:Stroke Volume; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*; D016896:Treatment Outcome; D016277:Ventricular Function, Left / Q000502:physiology*
chemical_list: D019275:Radiopharmaceuticals