Following acute myocardial infarction (AMI) there is evidence of sustained sympathetic overactivity. This has been shown to contribute to left ventricular (LV) remodelling in animals. Increased tissue levels of noradrenaline lead to a reduction of β-adrenoceptor (βAR) density, which can be measured non invasively with positron emission tomography (PET). The aim of this study was to assess 1- if there is a reduction of myocardial βAR density 1 month after AMI and 2- if this βAR density correlates with changes in LV volumes at 6 months. We studied 42 patients (mean age 53±12 years) who suffered AMI. They had no previous angina, diabetes, hypertension or renal disease and all had single vessel disease. LV end systolic (ESV) and end diastolic (EDV) volumes were determined at 1 week and 6 months after AMI using echocardiography. Changes (d) in ESV and EDV were calculated by dividing the 6 month by the 1 week result. Myocardial βAR density and the coronary vasodilator reserve (CVR, dipyridamole) were measured 1 month after AMI using PET with 11CGP 12177 and H215O respectively. Results: The average ESV at 1 week was 61±20 ml compared to 64±28 ml at 6 months (p=ns) while the respective EDV values were 111±31 and 121±40 ml (p=ns). The patients had significantly reduced βAR density (5.95±0.99 pmol/g) compared to controls (8.35±2.00 pmol/g, p=0.0001). The CVR was also lower in patients (1.81±0.75) compared to controls (3.22±1.19, p=0.0001). In patients there was a significant correlation between lower βAR and higher dEDV (r=0.42, p=0.006). There was a significant correlation between lower CVR and higher dESV (r=0.33, p=0.04) and dEDV (r=0.98, p=0.05). Conclusion: 1. We have shown a significant reduction in βAR density post AMI patients compared to controls. 2. There is significant correlation between lower βAR and deterioration in ESV at 6 months post AMI. 3. There is a significant correlation between lower CVR and deterioration in ESV and EDV post AMI.
|Issue number||SUPPL. 1|
|Publication status||Published - May 1998|
ASJC Scopus subject areas
- Cardiology and Cardiovascular Medicine