title: The angiotensin-converting enzyme gene I/D polymorphism and heart rate variability following acute myocardial infarction.
abstract: OBJECTIVE
  Heart rate variability (HRV) is a measure of cardiac autonomic control and is therefore subject to regulation by the renin-angiotensin system. The primary objective of this study was to determine the effect of an insertion/deletion polymorphism within the angiotensin-converting enzyme (ACE) gene on HRV in the early stages after a myocardial infarction at a time when cardiac autonomic control is deranged. The secondary objective was to determine whether this polymorphism affected the HRV response to inhibition of ACE.
  
  
  RESULTS
  149 Caucasian subjects were studied 25 +/- 16 h following MI using time and frequency domain measures of HRV derived from two 5-minute ECG recordings. Recordings were repeated at 182 +/- 65 h following MI, when subjects had been stabilised on ramipril 2.5 mg bd. The study included 46 subjects with the DD genotype, 69 with the ID genotype, and 34 with the II genotype. No effect of the I/D polymorphism on short-term recordings of HRV was found. There was no difference in HRV response to the introduction of ramipril according to the genotypes.
  
  
  CONCLUSIONS
  The I/D polymorphism within the ACE gene does not influence HRV after MI or the HRV response to ACE inhibitor therapy with ramipril. These findings may reflect the relative lack of importance of the I/D polymorphism and ACE activity in determining plasma and tissue angiotensin II concentration after a major stimulus to the renin-angiotensin system as occurs after myocardial infarction.
authors.affiliation: Department of Cardiology, Royal Hallamshire Hospital, Sheffield, UK. R.P.Steeds@shef.ac.uk
authors.forename: Richard P
authors.initials: RP
authors.lastname: Steeds
authors.forename: Janine
authors.initials: J
authors.lastname: Fletcher
authors.forename: Helen
authors.initials: H
authors.lastname: Parry
authors.forename: Saquib
authors.initials: S
authors.lastname: Chowdhary
authors.forename: Kevin S
authors.initials: KS
authors.lastname: Channer
authors.forename: John
authors.initials: J
authors.lastname: West
authors.forename: John N
authors.initials: JN
authors.lastname: Townend
mesh_terms: D000368:Aged; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000008:administration & dosage; D005260:Female; D005838:Genotype; D006339:Heart Rate / Q000187:drug effects / Q000235:genetics*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000188:drug therapy / Q000235:genetics* / Q000503:physiopathology; D007703:Peptidyl-Dipeptidase A / Q000235:genetics*; D011110:Polymorphism, Genetic; D017257:Ramipril / Q000008:administration & dosage; D012084:Renin-Angiotensin System / Q000235:genetics
chemical_list: D000806:Angiotensin-Converting Enzyme Inhibitors; D007703:Peptidyl-Dipeptidase A; D017257:Ramipril