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Autonomic correlates of late infarct artery patency after first myocardial infarction
O Odemuyiwa1, P Jordaan, M Malik
1Department of Cardiological Sciences, St. George's Hospital Medical School, London, England.
Insights
Occluded infarct arteries and poor left ventricular function are linked to higher risks of sudden death after myocardial infarction. Depressed heart rate variability (HRV) also indicates increased risk in these patients.
Area of Science:
- Cardiology
- Clinical Medicine
- Mocardial Infarction Research
Background:
- Artery occlusion post-myocardial infarction (MI) is linked to sudden death risk, especially with impaired left ventricular function.
- Depressed heart rate variability (HRV) is a known risk factor for sudden cardiac death in post-MI patients.
Purpose of the Study:
- To investigate the relationship between infarct-related artery patency, left ventricular function, and HRV in myocardial infarction survivors.
Main Methods:
- 186 survivors of a first myocardial infarction underwent predischarge coronary angiography and Holter monitoring.
- Coronary angiography was indicated by abnormal exercise test findings.
- Left ventricular ejection fraction (EF) and HRV were assessed.
Main Results:
- Patients with occluded infarct arteries had significantly lower mean ejection fraction (49% vs 55%, p < 0.001).
- A higher proportion of patients with EF < 40% had reduced HRV (< 20 U) compared to those with EF > 40% (18% vs 5%, p < 0.02).
Conclusions:
- Infarct artery patency is associated with better left ventricular function post-MI.
- Reduced HRV is more prevalent in patients with poorer left ventricular function after myocardial infarction.
Abstract:
Occlusion of the infarct-related artery has recently been associated with an increased risk of sudden death, particularly in patients with poor left ventricular function. Depressed heart rate variability (HRV) also identifies postinfarction patients at an increased risk of sudden death. The correlation between infarct artery patency, left ventricular function, and HRV was therefore examined in 186 survivors of a first myocardial infarction. Predischarge coronary angiography and Holter monitoring were carried out in 186 patients with a first acute myocardial infarction. Coronary angiography was performed because of abnormal predischarge exercise test findings. Mean age (56 +/- 9 years) and the proportions of type and site of infarction did not differ between patients with occluded or patent arteries or between patients who did or did not undergo coronary angiography. The mean left ventricular ejection fraction (EF) was 55 +/- 15% in patients with patent and 49 +/- 14% in those with occluded infarct arteries (p < 0.001), and the EF was < 40% in 17% and 28% of the respective groups (p < 0.05). HRV was < 20 U in 7 (18%) of the 39 patients with an EF < 40% but in only 7 (5%) of the 147 patients with an EF > 40% (p < 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)