title: J-waves in patients with an acute ST-elevation myocardial infarction who underwent successful percutaneous coronary intervention: prevalence, pathogenesis, and clinical implication.
abstract: OBJECTIVE
  The prevalence, clinical significance, and pathogenesis of J-waves were studied in the patients with an ST-elevation myocardial infarction (MI) after percutaneous coronary intervention (PCI).
  
  
  RESULTS
  One hundred and fifty-two consecutive patients with an acute ST-elevation MI were included. The mean age was 68.6 ± 13.5 years, and 78.3% of the patients were male. Following successful PCI, 12-lead electrocardiograms (ECGs) were monitored, and J-waves were measured 1 week after the MI and analysed in relation to the location of the MI and arrhythmias. Clinical and ECG parameters were compared between the groups with and without J-waves. The rate dependency of the J-wave amplitude was analysed in the conducted atrial premature beats (APBs). J-waves were present in 60.5% (≥0.1 mV) or 48.9% (≥0.2 mV) of the 152 patients. The J-waves were more often located in the inferior leads and more frequently in an inferior MI. The presence of J-waves was associated with ventricular arrhythmias, including ventricular fibrillation. The J-wave amplitude increased in the conducted APB, mechanistically suggesting a phase 3 block.
  
  
  CONCLUSIONS
  Many patients in the early recovery phase after an acute MI had J-waves. This ECG phenomenon was associated with an increased incidence of ventricular arrhythmias. The tachycardia-dependent augmentation of the J-wave amplitude suggested a mechanistic role of conduction delay.
authors.affiliation: Tachikawa General Hospital, Cardiovascular Center, Nagaoka,  Japan.
authors.forename: Masafumi
authors.initials: M
authors.lastname: Nakayama
authors.forename: Masahito
authors.initials: M
authors.lastname: Sato
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Kitazawa
authors.forename: Atsushi
authors.initials: A
authors.lastname: Saito
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Ikeda
authors.forename: Satoru
authors.initials: S
authors.lastname: Fujita
authors.forename: Koichi
authors.initials: K
authors.lastname: Fuse
authors.forename: Minoru
authors.initials: M
authors.lastname: Takahashi
authors.forename: Ken
authors.initials: K
authors.lastname: Takarada
authors.forename: Takeo
authors.initials: T
authors.lastname: Oguro
authors.forename: Hirooki
authors.initials: H
authors.lastname: Matsushita
authors.forename: Masaaki
authors.initials: M
authors.lastname: Okabe
authors.forename: Akira
authors.initials: A
authors.lastname: Yamashina
authors.forename: Yoshifusa
authors.initials: Y
authors.lastname: Aizawa
mesh_terms: D000368:Aged; D015897:Comorbidity; D004562:Electrocardiography / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D015994:Incidence; D007564:Japan / Q000453:epidemiology; D008297:Male; D009203:Myocardial Infarction / Q000453:epidemiology* / Q000601:surgery*; D062645:Percutaneous Coronary Intervention / Q000706:statistics & numerical data*; D011183:Postoperative Complications / Q000453:epidemiology*; D012307:Risk Factors; D017180:Tachycardia, Ventricular / Q000453:epidemiology*; D014693:Ventricular Fibrillation / Q000453:epidemiology*