Is glycated haemoglobin a sensitive index to identify left ventricular dysfunction two months after acute myocardial
Abdul-Majeed Salmasi1, Peter Frost, Mark Dancy
1Cardiac Research Unit, Cardiology Department, Pathology, Central Middlesex Hospital, Acton Lane, London NW10 7NS, United Kingdom. majeed.salmasi@nwlh.nhs.uk
Insights
Glycated haemoglobin (HbA1c) levels correlate with left ventricular (LV) systolic and diastolic function two months after acute myocardial infarction (AMI). Higher HbA1c predicts impaired LV relaxation and is specific for non-restrictive LV filling.
Area of Science:
- Cardiology
- Metabolic Disorders
- Cardiac Imaging
Background:
- Glycated haemoglobin (HbA1c) reflects glucose metabolism.
- Glucose intolerance is linked to left ventricular (LV) dysfunction post-acute myocardial infarction (AMI).
- This study investigates HbA1c in relation to LV function in non-diabetic patients after AMI.
Purpose of the Study:
- To assess the relationship between HbA1c and LV function.
- To evaluate HbA1c as a predictor of diastolic and systolic dysfunction post-AMI.
- To analyze HbA1c in normotensive patients without prior diabetes diagnosis following AMI.
Main Methods:
- Oral glucose tolerance test (GTT) and HbA1c measurements.
- Echocardiography and Doppler-cardiography to assess LV function parameters (E/A, DT, LVEF, LV mass index).
- Evaluation of LV diastolic function at rest and during isometric exercise (IME).
Main Results:
- HbA1c >6.0% was observed in 67% of patients with impaired LV relaxation during IME.
- HbA1c showed 68% sensitivity and 37% specificity for predicting impaired LV relaxation.
- HbA1c was significantly related to LVEF, DT, and E/A, but not LV mass index or other clinical factors.
Conclusions:
- HbA1c correlates with both systolic and diastolic LV function two months post-AMI.
- HbA1c is a sensitive predictor of impaired LV relaxation.
- HbA1c is highly specific for ruling out non-restrictive LV filling post-AMI.
Background:
Glycated haemoglobin concentration (HbA1c) is a marker of glucose metabolism. Glucose intolerance is associated with a high incidence of left ventricular (LV) dysfunction after acute myocardial infarction (AMI). This study was carried out in order to relate HbA1c to LV function two months following AMI in 171 normotensive patients who were not previously known to have had diabetes mellitus.
Methods:
Oral glucose tolerance test (GTT) and HbA1c. Echo and Doppler-cardiography were used to measure the E/A (peak velocity of the early filling/atrial contraction waves) at rest and at peak isometric exercise (IME), deceleration time (DT) of E wave, LV ejection fraction (LVEF), LV mass index and diastolic LV function.
Results:
GTT was diabetic in 20, impaired in 35 and normal in 116 subjects. HbA1c was >6.0% (cut off level for high risk subjects) in 76 patients (67%) with impaired relaxation (E/A<1) during IME and in 30 patients (27%) with restrictive LV filling (identified by E/A=1-2, DT<140 ms). The sensitivity and specificity of HbA1c to predict underlying impaired LV relaxation were 68% and 37%, respectively, and to predict restrictive LV filling were 27% and 98%, respectively. Whereas in univariate analysis, DT.3 was linearly related to HbA1c only (p=0.0002), multiple regression analysis showed that HbA1c was related to LVEF, DT and E/A but not to LVH, LVMI, smoking habit, age, gender and creatinine kinase level during admission for AMI.
Conclusion:
At 2 months after admission for AMI, HbA1c is related to systolic and diastolic LV function but not to LVMI or LVH. HbA1c is a sensitive predictor of impaired relaxation but highly specific to rule out underlying non-restrictive LV filling.
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