title: Feasibility and safety of adenosine cardiovascular magnetic resonance in patients with MR conditional pacemaker systems at 1.5 Tesla.
abstract: BACKGROUND
  Cardiovascular Magnetic Resonance (CMR) with adenosine stress is a valuable diagnostic tool in coronary artery disease (CAD). However, despite the development of MR conditional pacemakers CMR is not yet established in clinical routine for pacemaker patients with known or suspected CAD. A possible reason is that adenosine stress perfusion for ischemia detection in CMR has not been studied in patients with cardiac conduction disease requiring pacemaker therapy. Other than under resting conditions it is unclear whether MR safe pacing modes (paused pacing or asynchronous mode) can be applied safely because the effect of adenosine on heart rate is not precisely known in this entity of patients. We investigate for the first time feasibility and safety of adenosine stress CMR in pacemaker patients in clinical routine and evaluate a pacing protocol that considers heart rate changes under adenosine.
  
  
  METHODS
  We retrospectively analyzed CMR scans of 24 consecutive patients with MR conditional pacemakers (mean age 72.1 ± 11.0 years) who underwent CMR in clinical routine for the evaluation of known or suspected CAD. MR protocol included cine imaging, adenosine stress perfusion and late gadolinium enhancement.
  
  
  RESULTS
  Pacemaker indications were sinus node dysfunction (n = 18) and second or third degree AV block (n = 6). Under a pacing protocol intended to avoid competitive pacing on the one hand and bradycardia due to AV block on the other no arrhythmia occurred. Pacemaker stimulation was paused to prevent competitive pacing in sinus node dysfunction with resting heart rate >45 bpm. Sympatho-excitatory effect of adenosine led to a significant acceleration of heart rate by 12.3 ± 8.3 bpm (p < 0.001), no bradycardia occurred. On the contrary in AV block heart rate remained constant; asynchronous pacing above resting heart rate did not interfere with intrinsic rhythm.
  
  
  CONCLUSIONS
  Adenosine stress CMR appears to be feasible and safe in patients with MR conditional pacemakers. Heart rate response to adenosine has to be considered for the choice of pacing modes during CMR.
authors.affiliation: Deptartment of Cardiology, Katholisches Klinikum Essen, University of Witten/Herdecke, Hülsmannstraße 17, 45355, Essen, Germany. o.klein-wiele@kk-essen.de.
authors.forename: Oliver
authors.initials: O
authors.lastname: Klein-Wiele
authors.affiliation: Department of Radiology, Grönemeyer Institut Bochum, University of Witten/Herdecke, Universitätsstraße 142, 44799, Bochum, Germany. garmer@groenemeyer.com.
authors.forename: Marietta
authors.initials: M
authors.lastname: Garmer
authors.affiliation: Deptartment of Cardiology, Katholisches Klinikum Essen, University of Witten/Herdecke, Hülsmannstraße 17, 45355, Essen, Germany. r.urbien@kk-essen.de.
authors.forename: Rhyan
authors.initials: R
authors.lastname: Urbien
authors.affiliation: Department of Radiology, Grönemeyer Institut Bochum, University of Witten/Herdecke, Universitätsstraße 142, 44799, Bochum, Germany. busch@groenemeyer.com.
authors.forename: Martin
authors.initials: M
authors.lastname: Busch
authors.affiliation: Cardiovascular Centre, Josef Hospital, University of Bochum, Gudrunstr. 56, 44791, Bochum, Germany. k.kara@klinikum-bochum.de.
authors.forename: Kaffer
authors.initials: K
authors.lastname: Kara
authors.affiliation: Department of Radiology, Grönemeyer Institut Bochum, University of Witten/Herdecke, Universitätsstraße 142, 44799, Bochum, Germany. mateiescu@groenemeyer.com.
authors.forename: Serban
authors.initials: S
authors.lastname: Mateiescu
authors.affiliation: Department of Radiology, Grönemeyer Institut Bochum, University of Witten/Herdecke, Universitätsstraße 142, 44799, Bochum, Germany. dr.groenemeyer@groenemeyer.com.
authors.forename: Dietrich
authors.initials: D
authors.lastname: Grönemeyer
authors.affiliation: Deptartment of Cardiology, Katholisches Klinikum Essen, University of Witten/Herdecke, Hülsmannstraße 17, 45355, Essen, Germany. Michael.Schulte-Hermes@prosper-hospital.de.|Department of Cardiology, Prosper-Hospital Recklinghausen, University of Witten/Herdecke, Mühlenstraße 27, 45659, Recklinghausen, Germany. Michael.Schulte-Hermes@prosper-hospital.de.
authors.forename: Michael
authors.initials: M
authors.lastname: Schulte-Hermes
authors.affiliation: Deptartment of Cardiology, Katholisches Klinikum Essen, University of Witten/Herdecke, Hülsmannstraße 17, 45355, Essen, Germany.
authors.forename: Marc
authors.initials: M
authors.lastname: Garbrecht
authors.affiliation: Deptartment of Cardiology, Katholisches Klinikum Essen, University of Witten/Herdecke, Hülsmannstraße 17, 45355, Essen, Germany. b.hailer@kk-essen.de.
authors.forename: Birgit
authors.initials: B
authors.lastname: Hailer
mesh_terms: D000241:Adenosine / Q000008:administration & dosage* / Q000009:adverse effects; D000368:Aged; D000369:Aged, 80 and over; D001145:Arrhythmias, Cardiac / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy*; D001783:Blood Flow Velocity; D002304:Cardiac Pacing, Artificial / Q000009:adverse effects / Q000379:methods; D003287:Contrast Media; D003324:Coronary Artery Disease / Q000175:diagnosis* / Q000503:physiopathology; D003326:Coronary Circulation; D003331:Coronary Vessels / Q000503:physiopathology*; D004867:Equipment Design; D005240:Feasibility Studies; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D019028:Magnetic Resonance Imaging, Cine / Q000009:adverse effects / Q000379:methods*; D008297:Male; D008875:Middle Aged; D055414:Myocardial Perfusion Imaging / Q000379:methods*; D010138:Pacemaker, Artificial / Q000009:adverse effects; D061214:Patient Safety; D011237:Predictive Value of Tests; D012039:Regional Blood Flow; D012189:Retrospective Studies; D012307:Risk Factors; D014665:Vasodilator Agents / Q000008:administration & dosage* / Q000009:adverse effects
chemical_list: D003287:Contrast Media; D014665:Vasodilator Agents; D000241:Adenosine