title: Circadian Rhythm of Infarct Size and Left Ventricular Function Evaluated with Tissue Doppler Echocardiography in ST Elevation Myocardial Infarction.
abstract: We aimed to investigate the circadian rhythm on left ventricular (LV) function and infarct size, according to the onset of ST elevation myocardial infarction (STEMI), with echocardiography in patients with first STEMI successfully revascularised with primary percutaneous coronary intervention (PCI).
  
  
  
  We conducted a retrospective analysis of 252 STEMI patients. Patients were divided into the four, six-hour periods of the day. Conventional and tissue Doppler imaging (TDI) echocardiography were performed within 48hours after onset of chest pain. The average of peak systolic myocardial velocities (Sm) in each of the four myocardial segments and LV ejection fraction (LVEF) were calculated.
  
  
  
  A negative linear correlation was shown between CK-MB levels and Sm (r= -0.209, p=0.001). There was an oscillation between time of day and average of Sm. The lowest Sm and largest infarct size were in the period of 06:00-noon compared with period of noon-18:00 and 18:00-midnight (p=0.029 and p=0.031, respectively). A secondary analysis showed that both LVEF and Sm were lower in the midnight-noon group compared with the noon-midnight group (44.9±7.3% versus 47.3±7.9%, p=0.018, and 7.6±1.4cm/s versus 8.2±1.6cm/s, p=0.003, respectively).
  
  
  
  This study has shown that there was a circadian rhythm of infarct size and LV function evaluated by echocardiography according to time of STEMI onset. The largest infarct size and poor LV function occurred in the midnight-noon period, in particular in the 06:00-noon period.
authors.affiliation: Suleyman Demirel University, Faculty of Medicine, Cardiology Department, Isparta/Turkey.
authors.forename: Hatem
authors.initials: H
authors.lastname: Arı
authors.affiliation: Bezmialem Vakif University, Faculty of Medicine, Cardiology Department, Istanbul/Turkey.
authors.forename: Osman
authors.initials: O
authors.lastname: Sonmez
authors.affiliation: Selcuk University, Faculty of Medicine, Cardiology Department, Konya/Turkey.
authors.forename: Fatih
authors.initials: F
authors.lastname: Koc
authors.affiliation: Selcuk University, Faculty of Medicine, Cardiology Department, Konya/Turkey.
authors.forename: Yusuf
authors.initials: Y
authors.lastname: Alıhanoglu
authors.affiliation: Selcuk University, Faculty of Medicine, Cardiology Department, Konya/Turkey.
authors.forename: Kurtulus
authors.initials: K
authors.lastname: Ozdemır
authors.affiliation: Bezmialem Vakif University, Faculty of Medicine, Cardiology Department, Istanbul/Turkey. Electronic address: vatankulu@hotmail.com.
authors.forename: Mehmet Akif
authors.initials: MA
authors.lastname: Vatankulu
mesh_terms: D000328:Adult; D000368:Aged; D002940:Circadian Rhythm; D015150:Echocardiography, Doppler; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D062645:Percutaneous Coronary Intervention; D012189:Retrospective Studies; D013318:Stroke Volume; D016277:Ventricular Function, Left
keywords: Circadian; Echocardiography; Left ventricular function; Myocardial infarct size; Myocardial infarction; Tissue Doppler