title: Continuous vectorcardiographic monitoring of ischemia during coronary angioplasty in patients with bundle-branch block.
abstract: BACKGROUND
  Patients with the combination of bundle-branch block and ischemic heart disease have a poor outcome. There is no established criterion for detection of transient ischemia when bundle-branch block is present.
  
  
  OBJECTIVE
  To elucidate vectorcardiographic changes during coronary angioplasty of patients with bundle-branch block.
  
  
  METHODS
  The QRS complex and ST-segment changes of 29 patients with bundle-branch block were studied during elective coronary angioplasty using continuous vectorcardiography. Data for the patients with bundle-branch block were compared with data for narrow-QRS-complex controls, matched for the vessel dilated, sex, and age.
  
  
  RESULTS
  Patients with bundle-branch block were found to have more pronounced changes in the QRS-vector difference as a response to coronary occlusion than did controls. ST-vector magnitude responded in a similar way during coronary occlusion of patients with and without bundle-branch block but from different baselines. ST change-vector magnitude was found to be the most sensitive parameter for detection of ischemia in patients with bundle-branch block as well as for controls.
  
  
  CONCLUSIONS
  Monitoring of transient ischemia during coronary angioplasty for patients with bundle-branch block is feasible using continuous vectorcardiography. A change in ST vector magnitude > 100 microV is suggested to indicate significant ischemia in the presence of bundle-branch block.
authors.affiliation: Clinical Experimental Research Laboratory, Sahlgrenska University Hospital, Ostra, Sweden.
authors.forename: P
authors.initials: P
authors.lastname: Eriksson
authors.forename: P
authors.initials: P
authors.lastname: Albertsson
authors.forename: L
authors.initials: L
authors.lastname: Ekström
authors.forename: M
authors.initials: M
authors.lastname: Dellborg
mesh_terms: D000368:Aged; D015906:Angioplasty, Balloon, Coronary / Q000379:methods*; D002037:Bundle-Branch Block / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008151:Lown-Ganong-Levine Syndrome / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000379:methods*; D017202:Myocardial Ischemia / Q000503:physiopathology*; D012680:Sensitivity and Specificity; D013616:Tachycardia, Sinus / Q000503:physiopathology; D014672:Vectorcardiography / Q000379:methods*