title: Do collaterals affect heart rate variability in patients with acute myocardial infarction?
abstract: BACKGROUND
  The protective effects and the prognostic importance of collaterals during and after acute myocardial infarction (MI) are under debate and heart rate variability (HRV) is a strong predictor of risk of mortality and arrhythmic events after acute MI. We aimed to examine the effects of collateral circulation on HRV in the early period after acute MI.
  
  
  METHODS
  Sixty-four patients admitted to our clinics who were diagnosed with acute anterior MI and underwent thrombolytic therapy were enrolled in this study. We applied 24 h Holter monitoring for HRV analysis to all patients and compared the patients with and without collaterals to the infarct-related artery.
  
  
  RESULTS
  Mean heart rate, low frequency (LF) (day, night and 24 h) and LF/high frequency (HF) (day, night and 24 h) were higher, SD of all NN intervals (SDNN), root mean square of successive differences (RMSSD), number of NN intervals that differed by more than 50 ms from the adjacent interval divided by the total number of all NN intervals (PNN50) and HF night values were lower in patients without collaterals than in those with collaterals. SDNN was negatively correlated with left anterior descending coronary artery (LAD) stenosis, ventricle score indices and left ventricular ejection fraction (LVEF); LF/HF ratio was positively correlated with ventricle score indices and negatively correlated with LVEF and Thrombolysis in Myocardial Infarction flow grade. Linear regression analysis showed that ventricle score index and coronary collaterals affect HRV and LAD stenosis, ventricle score, LVEF and coronary collaterals affect LF/HF ratio. A SDNN <80 ms increased the development of ventricular arrhythmias in the early period by 4.7 fold, a LF/HF ratio >2.7 increased it by 9.8 fold and a LVEF <35% increased it by 12.8 fold, whereas the presence of well-developed collaterals decreased the arrhythmia development by 2.5 fold.
  
  
  CONCLUSIONS
  The collaterals to the infarct-related artery have great impact on HRV, autonomic nervous system activity and the development of ventricular arrhythmias in patients with acute anterior MI. Our results suggest a protective role of collaterals on myocardial electrophysiology in the early period after acute MI.
authors.affiliation: Cardiology Clinics, Yüksek Ihtisas Hospital, Ankara, Turkey. drozdemir75@yahoo.com
authors.forename: Ozcan
authors.initials: O
authors.lastname: Ozdemr
authors.forename: Mustafa
authors.initials: M
authors.lastname: Soylu
authors.forename: Ahmet Duran
authors.initials: AD
authors.lastname: Demr
authors.forename: Bilal
authors.initials: B
authors.lastname: Geyk
authors.forename: Omer
authors.initials: O
authors.lastname: Alyan
authors.forename: Gökhan
authors.initials: G
authors.lastname: Chan
authors.forename: Serkan
authors.initials: S
authors.lastname: Topaloglu
authors.forename: Dursun
authors.initials: D
authors.lastname: Aras
authors.forename: Yücel
authors.initials: Y
authors.lastname: Balbay
authors.forename: Hatice
authors.initials: H
authors.lastname: Sasmaz
mesh_terms: D003097:Collateral Circulation / Q000502:physiology*; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000503:physiopathology*