title: Impaired hyperemic myocardial blood flow is associated with inducibility of ventricular arrhythmia in ischemic cardiomyopathy.
abstract: BACKGROUND
  Risk stratification for ventricular arrhythmias (VAs) is important to refine selection criteria for primary prevention implantable cardioverter defibrillator therapy. Impaired hyperemic myocardial blood flow (MBF) is associated with increased mortality rate in ischemic and nonischemic cardiomyopathy, which may be attributed to electric instability inducing VAs. The aim of this pilot study was to assess whether hyperemic MBF impairment may be related with VA inducibility in patients with ischemic cardiomyopathy.
  
  
  RESULTS
  Thirty patients with ischemic cardiomyopathy referred for primary prevention implantable cardioverter defibrillator implantation were prospectively included (26 men; 65±8 years old; left ventricular ejection fraction, 29±6%). [15O]H2O positron-emission tomography was performed to quantify resting MBF, hyperemic MBF, and coronary flow reserve. Left ventricular dimensions, function, and scar burden were assessed with cardiovascular magnetic resonance imaging. An electrophysiological study was performed to test VA inducibility. Positive electrophysiological study patients (n=12) showed reduced hyperemic MBF (1.25±0.30 versus 1.66±0.38 mL·min(-1)·g(-1); P<0.01) and coronary flow reserve (1.59±0.49 versus 2.12±0.48; P<0.01) compared with electrophysiological study negative patients (n=18). In electrophysiological study positive patients, the number of scar segments>75% transmurality was higher (P<0.05), although scar size and border zone did not differ. Receiver-operating characteristic curve analysis indicated that impaired hyperemic MBF (area under the curve, 0.84; 95% confidence intervals [0.69-0.99]) and coronary flow reserve (area under the curve, 0.77; 95% confidence intervals [0.57-0.96]) were associated with VA inducibility.
  
  
  CONCLUSIONS
  In this pilot study, impaired hyperemic MBF and coronary flow reserve were associated with VA inducibility in patients with ischemic cardiomyopathy. These results are hypothesis generating for a potential role of quantitative positron-emission tomography perfusion imaging in risk stratification for VAs.
authors.affiliation: Department of Cardiology and Institute for Cardiovascular Research, Departments of Radiology and Nuclear Medicine, Epidemiology and Biostatistics, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Mischa T
authors.initials: MT
authors.lastname: Rijnierse
authors.forename: Stefan
authors.initials: S
authors.lastname: de Haan
authors.forename: Hendrik J
authors.initials: HJ
authors.lastname: Harms
authors.forename: Lourens F
authors.initials: LF
authors.lastname: Robbers
authors.forename: LiNa
authors.initials: L
authors.lastname: Wu
authors.forename: Ibrahim
authors.initials: I
authors.lastname: Danad
authors.forename: Aernout M
authors.initials: AM
authors.lastname: Beek
authors.forename: Martijn W
authors.initials: MW
authors.lastname: Heymans
authors.forename: Albert C
authors.initials: AC
authors.lastname: van Rossum
authors.forename: Adriaan A
authors.initials: AA
authors.lastname: Lammertsma
authors.forename: Cornelis P
authors.initials: CP
authors.lastname: Allaart
authors.forename: Paul
authors.initials: P
authors.lastname: Knaapen
mesh_terms: D000368:Aged; D019540:Area Under Curve; D001145:Arrhythmias, Cardiac / Q000175:diagnosis / Q000209:etiology* / Q000503:physiopathology; D009202:Cardiomyopathies / Q000175:diagnosis / Q000209:etiology* / Q000503:physiopathology; D003326:Coronary Circulation; D022062:Electrophysiologic Techniques, Cardiac; D005260:Female; D006801:Humans; D006940:Hyperemia / Q000503:physiopathology*; D016015:Logistic Models; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000150:complications* / Q000175:diagnosis / Q000503:physiopathology; D055414:Myocardial Perfusion Imaging / Q000379:methods; D016017:Odds Ratio; D010865:Pilot Projects; D049268:Positron-Emission Tomography; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012372:ROC Curve; D018570:Risk Assessment; D012307:Risk Factors; D013318:Stroke Volume; D016277:Ventricular Function, Left
keywords: defibrillators, implantable; ischemic cardiomyopathy; perfusion imaging; positron-emission tomography; tachycardia, ventricular