title: Electrical alternans induced by a brief period of myocardial ischemia during percutaneous coronary intervention: The characteristic ECG morphology and relationship to mechanical alternans.
abstract: BACKGROUND
  Electrical alternans (EA) has not been fully studied in the current percutaneous coronary intervention (PCI) procedure.
  
  
  OBJECTIVE
  The purpose of this study was to evaluate visible EA and the morphology of ST segment during PCI.
  
  
  METHODS
  The incidence of visible EA and ST-segment morphology were studied while the coronary artery was occluded for 20 seconds. When data were available, the relationship between EA and blood pressure was analyzed. The clinical and electrocardiographic data were compared with those of the age- and sex-matched controls.
  
  
  RESULTS
  During balloon inflation, visible EA was observed in 5 of 306 patients (1.6%) in the last 2 years. EA was limited to PCI in the proximal left anterior descending artery. The ST segment elevated to 10.1 ± 3.2 mm, followed by an alternating QRS complex with a lower ST segment (5.6 ± 1.9 mm; P = .0047) with characteristic ST-segment morphology, which is known as lambda pattern. The mean age of the 5 patients was 68 ± 20 years, and 4(80%). were men. After the release of inflation, the ST-segment level returned rapidly to baseline, followed by normalization of J point. Compared with controls, the maximal elevated ST segment was significantly higher in patients with EA (5.7 ± 2.7 mm; P = .0028). The occlusion of the proximal left anterior descending artery with more severe ischemia seemed to be a prerequisite for developing EA. A higher ST segment was associated with a lower blood pressure and vice versa.
  
  
  CONCLUSIONS
  A short period of ischemia during PCI may induce visible EA and alternating QRS complexes with a characteristic ST-segment morphology. A higher ST segment was associated with a lower blood pressure and vice versa.
authors.affiliation: Department of Cardiology, Tachikawa General Hospital, Nagaoka, Japan.
authors.forename: Takeo
authors.initials: T
authors.lastname: Oguro
authors.affiliation: Department of Cardiology, Tachikawa General Hospital, Nagaoka, Japan.
authors.forename: Masatsune
authors.initials: M
authors.lastname: Fujii
authors.affiliation: Department of Cardiology, Tachikawa General Hospital, Nagaoka, Japan.
authors.forename: Koichi
authors.initials: K
authors.lastname: Fuse
authors.affiliation: Department of Cardiology, Tachikawa General Hospital, Nagaoka, Japan.
authors.forename: Minoru
authors.initials: M
authors.lastname: Takahashi
authors.affiliation: Department of Cardiology, Tachikawa General Hospital, Nagaoka, Japan.
authors.forename: Satoru
authors.initials: S
authors.lastname: Fujita
authors.affiliation: Department of Cardiology, Tachikawa General Hospital, Nagaoka, Japan.
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Kitazawa
authors.affiliation: Department of Cardiology, Tachikawa General Hospital, Nagaoka, Japan.
authors.forename: Masahito
authors.initials: M
authors.lastname: Sato
authors.affiliation: Department of Cardiology, Tachikawa General Hospital, Nagaoka, Japan.
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Ikeda
authors.affiliation: Department of Cardiology, Tachikawa General Hospital, Nagaoka, Japan.
authors.forename: Masaaki
authors.initials: M
authors.lastname: Okabe
authors.affiliation: Department of Research and Development Tachikawa Medical Center, Nagaoka, Japan. Electronic address: aizaways@med.niigata-u.ac.jp.
authors.forename: Yoshifusa
authors.initials: Y
authors.lastname: Aizawa
mesh_terms: D015906:Angioplasty, Balloon, Coronary / Q000009:adverse effects / Q000379:methods*; D001145:Arrhythmias, Cardiac / Q000209:etiology*; D016022:Case-Control Studies; D003327:Coronary Disease / Q000175:diagnosis / Q000401:mortality / Q000628:therapy*; D004562:Electrocardiography / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D017202:Myocardial Ischemia / Q000175:diagnosis* / Q000401:mortality / Q000628:therapy*; D062645:Percutaneous Coronary Intervention / Q000009:adverse effects / Q000379:methods; D012016:Reference Values; D018570:Risk Assessment; D012720:Severity of Illness Index; D015996:Survival Rate; D016896:Treatment Outcome
keywords: Electrical alternans; Percutaneous coronary intervention; ST-T morphology