title: Cardiac resynchronization therapy guided by late gadolinium-enhancement cardiovascular magnetic resonance.
abstract: BACKGROUND
  Myocardial scarring at the LV pacing site leads to incomplete resynchronization and a suboptimal symptomatic response to CRT. We sought to determine whether the use of late gadolinium cardiovascular magnetic resonance (LGE-CMR) to guide left ventricular (LV) lead deployment influences the long-term outcome of cardiac resynchronization therapy (CRT).
  
  
  METHODS
  559 patients with heart failure (age 70.4 ± 10.7 yrs [mean ± SD]) due to ischemic or non-ischemic cardiomyopathy underwent CRT. Implantations were either guided (+CMR) or not guided (-CMR) by LGE-CMR prior to implantation. Fluoroscopy and LGE-CMR were used to localize the LV lead tip and and myocardial scarring retrospectively. Clinical events were assessed in three groups: +CMR and pacing scar (+CMR+S); CMR and not pacing scar (+CMR-S), and; LV pacing not guided by CMR (-CMR).
  
  
  RESULTS
  Over a maximum follow-up of 9.1 yrs, +CMR+S had the highest risk of cardiovascular death (HR: 6.34), cardiovascular death or hospitalizations for heart failure (HR: 5.57) and death from any cause or hospitalizations for major adverse cardiovascular events (HR: 4.74) (all P < 0.0001), compared with +CMR-S. An intermediate risk of meeting these endpoints was observed for -CMR, with HRs of 1.51 (P = 0.0726), 1.61 (P = 0.0169) and 1.87 (p = 0.0005), respectively. The +CMR+S group had the highest risk of death from pump failure (HR: 5.40, p < 0.0001) and sudden cardiac death (HR: 4.40, p = 0.0218), in relation to the +CMR-S group.
  
  
  CONCLUSIONS
  Compared with a conventional implantation approach, the use of LGE-CMR to guide LV lead deployment away from scarred myocardium results in a better clinical outcome after CRT. Pacing scarred myocardium was associated with the worst outcome, in terms of both pump failure and sudden cardiac death.
authors.affiliation: Centre for Cardiovascular Sciences, Queen Elizabeth Hospital, University of Birmingham, UK. cardiologists@hotmail.com
authors.forename: Francisco
authors.initials: F
authors.lastname: Leyva
authors.forename: Paul W X
authors.initials: PW
authors.lastname: Foley
authors.forename: Shajil
authors.initials: S
authors.lastname: Chalil
authors.forename: Karim
authors.initials: K
authors.lastname: Ratib
authors.forename: Russell E A
authors.initials: RE
authors.lastname: Smith
authors.forename: Frits
authors.initials: F
authors.lastname: Prinzen
authors.forename: Angelo
authors.initials: A
authors.lastname: Auricchio
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D058406:Cardiac Resynchronization Therapy / Q000009:adverse effects / Q000401:mortality; D058409:Cardiac Resynchronization Therapy Devices; D009202:Cardiomyopathies / Q000150:complications / Q000175:diagnosis / Q000401:mortality / Q000503:physiopathology / Q000628:therapy*; D002318:Cardiovascular Diseases / Q000209:etiology / Q000401:mortality; D016009:Chi-Square Distribution; D016757:Death, Sudden, Cardiac / Q000209:etiology / Q000517:prevention & control; D005260:Female; D006333:Heart Failure / Q000175:diagnosis / Q000209:etiology / Q000401:mortality / Q000503:physiopathology / Q000628:therapy*; D006760:Hospitalization; D006801:Humans; D053208:Kaplan-Meier Estimate; D053783:Magnetic Resonance Imaging, Interventional; D008297:Male; D008875:Middle Aged; D009206:Myocardium / Q000473:pathology; D016016:Proportional Hazards Models; D018570:Risk Assessment; D012307:Risk Factors; D013997:Time Factors; D016896:Treatment Outcome; D016277:Ventricular Function, Left; D020257:Ventricular Remodeling