title: FDG PET as a predictor of response to resynchronisation therapy in patients with ischaemic cardiomyopathy.
abstract: OBJECTIVE
  Although resynchronisation therapy (CRT) is a promising addition to heart failure therapy, a substantial number of patients do not respond to CRT. As FDG PET has routinely been used for prediction of improvement after revascularisation in ischaemic cardiomyopathy, it was hypothesised that there is also a relationship between the extent of viable tissue and improvement as a result of CRT.
  
  
  METHODS
  Thirty-nine patients with ischaemic cardiomyopathy (ejection fraction 27 +/- 9%) and a wide QRS complex underwent temporary pacing to determine the optimal pacing combination, i.e. that with the highest increase in cardiac index (CI) compared with baseline (measured by Doppler echocardiography). All patients also underwent FDG PET imaging. In 19 patients, CI measurements were repeated 10-12 weeks after permanent biventricular pacemaker implantation.
  
  
  RESULTS
  Echocardiography (13-segment model) showed a mean of 9.8 +/- 1.6 dyssynergic segments, with preserved FDG uptake in 4.1 +/- 2.4 segments. CI improvement at the optimal pacing site was 20 +/- 9%. There was a linear relationship between the extent of viable tissue and CI improvement during pacing (p < 0.001). Using a cut-off value of more than three viable segments (ROC analysis), FDG PET had a sensitivity of 72% and a specificity of 71% for detection of the presence of haemodynamic improvement (i.e. a CI improvement >15%). The relation between CI improvement and viable tissue was similar at follow-up.
  
  
  CONCLUSIONS
  A correlation was found between the extent of viable tissue and the haemodynamic response to CRT in patients with ischaemic cardiomyopathy, suggesting that FDG PET imaging may be useful to discriminate between responders and non-responders to CRT.
authors.affiliation: Department of Cardiology, VU University Medical Centre, Amsterdam, The Netherlands.
authors.forename: C M C
authors.initials: CM
authors.lastname: van Campen
authors.forename: Frans C
authors.initials: FC
authors.lastname: Visser
authors.forename: Arno P
authors.initials: AP
authors.lastname: van der Weerdt
authors.forename: Paul
authors.initials: P
authors.lastname: Knaapen
authors.forename: Emile F I
authors.initials: EF
authors.lastname: Comans
authors.forename: Adriaan A
authors.initials: AA
authors.lastname: Lammertsma
authors.forename: Carel C
authors.initials: CC
authors.lastname: de Cock
authors.forename: Cees A
authors.initials: CA
authors.lastname: Visser
mesh_terms: D000368:Aged; D002304:Cardiac Pacing, Artificial / Q000379:methods*; D009202:Cardiomyopathies / Q000150:complications* / Q000000981:diagnostic imaging*; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008297:Male; D017202:Myocardial Ischemia / Q000000981:diagnostic imaging* / Q000628:therapy*; D018579:Patient Selection; D049268:Positron-Emission Tomography / Q000379:methods*; D011379:Prognosis; D015203:Reproducibility of Results; D018570:Risk Assessment / Q000379:methods; D012307:Risk Factors; D012680:Sensitivity and Specificity; D016896:Treatment Outcome
chemical_list: D019788:Fluorodeoxyglucose F18