[Early recognition of exercise-induced myocardial ischemia by plasma free fatty acid]

To investigate whether or not myocardial free fatty acid (FFA) uptake is useful for early recognition of exercise-induced myocardial ischemia compared with myocardial lactate uptake, we studied in 8 patients with stable effort angina pectoris by measuring hemodynamic and metabolic parameters during supine multistage bicycle ergometer exercise (BEx). Analysis of FFA composition was performed by high performance liquid chromatography. The exercise endpoint in the control study was moderate chest pain in all cases. In all cases, BEx testing using the same method, duration and workload was repeated 1.5 hours after the oral administration of 6 mg of nilvadipine (a new calcium antagonist). Exercise time of the subjects studied was 463 +/- 40 sec (mean +/- SE, 180-540 sec). After administration of nilvadipine, chest pain was not induced in 6 patients and was lessened in severity in 2 patients. Mean ST segment depression was 0.21 +/- 0.05 mV in the control period and it was significantly reduced to 0.08 +/- 0.03 mV after nilvadipine administration (p less than 0.05). Myocardial FFA uptake decreased from 21.1 +/- 4.4% at rest to 8.1 +/- 2.1% at peak exercise in the control study (p less than 0.05). Myocardial lactate uptake was unchanged at rest and peak exercise in the control study (21.6 +/- 2.7 vs 22.2 +/- 3.3%). After administration of nilvadipine, myocardial FFA uptake did not change during BEx (25.3 +/- 2.7 at rest and 21.3 +/- 3.6% at peak exercise). At peak exercise, myocardial FFA uptake increased significantly after administration of nilvadipine (21.3 +/- 3.6 vs 8.1 +/- 2.1%, p less than 0.05). In FFA composition, the percentage of each of 12 FFA did not change during myocardial passage at rest and peak exercise.(ABSTRACT TRUNCATED AT 250 WORDS)