title: Impact of Heart Rate on Myocardial Salvage in Timely Reperfused Patients with ST-Segment Elevation Myocardial Infarction: New Insights from Cardiovascular Magnetic Resonance.
abstract: BACKGROUND
  Previous studies evaluating the progression of the necrotic wave in relation to heart rate were carried out only in animal models of ST-elevated myocardial infarction (STEMI). Aim of the study was to investigate changes of myocardial salvage in relation to different heart rates at hospital admission in timely reperfused patients with STEMI by using cardiovascular magnetic resonance (CMR).
  
  
  METHODS
  One hundred-eighty-seven patients with STEMI successfully and timely treated with primary coronary angioplasty underwent CMR five days after hospital admission. According to the heart rate at presentation, patients were subcategorized into 5 quintiles: <55 bpm (group I, n = 44), 55-64 bpm (group II, n = 35), 65-74 bpm (group III, n = 35), 75-84 bpm (group IV, n = 37), ≥85 bpm (group V, n = 36). Area at risk, infarct size, microvascular obstruction (MVO) and myocardium salvaged index (MSI) were assessed by CMR using standard sequences.
  
  
  RESULTS
  Lower heart rates at presentation were associated with a bigger amount of myocardial salvage after reperfusion. MSI progressively decreased as the heart rates increased (0.54 group I, 0.46 group II, 0.38 group III, 0.34 group IV, 0.32 group V, p<0.001). Stepwise multivariable analysis showed heart rate, peak troponin and the presence of MVO were independent predictor of myocardial salvage. No changes related to heart rate were observed in relation to area at risk and infarct size.
  
  
  CONCLUSIONS
  High heart rates registered before performing coronary angioplasty in timely reperfused patients with STEMI are associated with a reduction in salvaged myocardium. In particular, salvaged myocardium significantly reduced when heart rate at presentation is ≥85 bpm.
authors.affiliation: Department of Cardiology, Sapienza University of Rome, Rome, Italy.
authors.forename: Luca
authors.initials: L
authors.lastname: Arcari
authors.affiliation: Department of Cardiology, Sapienza University of Rome, Rome, Italy.
authors.forename: Sara
authors.initials: S
authors.lastname: Cimino
authors.affiliation: Department of Cardiology, Sapienza University of Rome, Rome, Italy.
authors.forename: Laura
authors.initials: L
authors.lastname: De Luca
authors.affiliation: Department of Radiology, Sapienza University of Rome, Rome Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Francone
authors.affiliation: Department of Radiology, Sapienza University of Rome, Rome Italy.
authors.forename: Nicola
authors.initials: N
authors.lastname: Galea
authors.affiliation: Department of Cardiology, Sapienza University of Rome, Rome, Italy.
authors.forename: Manuela
authors.initials: M
authors.lastname: Reali
authors.affiliation: Department of Radiology, Sapienza University of Rome, Rome Italy.
authors.forename: Iacopo
authors.initials: I
authors.lastname: Carbone
authors.affiliation: Department of Cardiology, Sapienza University of Rome, Rome, Italy.
authors.forename: Carlo
authors.initials: C
authors.lastname: Iacoboni
authors.affiliation: Department of Cardiology, Sapienza University of Rome, Rome, Italy.
authors.forename: Luciano
authors.initials: L
authors.lastname: Agati
mesh_terms: D015906:Angioplasty, Balloon, Coronary / Q000379:methods; D003326:Coronary Circulation / Q000502:physiology; D004562:Electrocardiography / Q000379:methods; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000473:pathology*; D015425:Myocardial Reperfusion / Q000379:methods; D009206:Myocardium / Q000473:pathology*; D011379:Prognosis; D016879:Salvage Therapy / Q000379:methods; D013997:Time Factors