Twenty patients with angina pectoris associated with obstructive coronary arterial disease were investigated by stressing the heart by atrial pacing. Arterial and coronary sinus blood was sampled and the time taken to provoke angina (pacing time) measured. Nine of the patients acted as a control group and did not receive beta-blocking drugs. In this group both pacing time and myocardial lactate extraction were reproducible provided that 45 minutes rest was allowed between pacing tests: we have called this period the myocardial recovery time. The 11 remaining patients were paced before and after beta-blockade, the rate being kept constant for each patient. In contrast to the control group, beta-blockade improved myocardial metabolism as shown by increased myocardial lactate extraction (P<002) and decreased glucose extraction (P
616BRITISH MEDICAL JOURNAL 13 SEPTEMBER 1975 matory conditions such as thrombophlebitis. Objective evidence of the beneficial effects of such treatment, however, has hitherto been lacking.In our trial, the radioactivity disappeared significantly more rapidly from the site of the thrombophlebitis in the heparinoidtreated patients than in those treated with the placebo (P <0-001). Furthermore, the disappearance or persistence of local symptoms and signs of thrombophlebitis closely followed the decline or increase in radioactivity.When 125I-labelled fibrinogen is injected intravenously it is incorporated into a forming thrombus. Repeated counts of radioactivity over the site of the thrombus and over areas where there are no thrombi allow a quantitative assessment of the fate of the thrombus.7 The decrease in the percentage difference of radioactivity over these two sites indicates the rate of thrombus dissolution; this has been confirmed by repeated phlebography. It is therefore reasonable to suggest that the rapid decline in radioactivity observed in the patients treated with the heparinoid cream probably represented lysis of thrombi and disappearance of radioactive fibrin/fibrinogen from locally accumulated inflammatory exudate.A drawback of this trial was that it did not provide clear evidence of the true extent of thrombolysis and the nature of residual intimal damage. Phlebography before and after treatment was not performed because of the risk that injection of contrast medium might produce further damage to the already inflamed intima and thus induce extension of the thrombotic process. Another objective method would have been to remove a small segment of affected vein under local anaesthesia and study it histologically to assess residual thrombus and intimal damage; such investigations were, however, considered unethical.In view of the clear evidence of symptomatic relief and objective evidence of rapid decline in local radioactivity it is hard to deny that the beneficial effects observed in patients receiving heparinoid ointment were due to the drug itself. Practice, 1970, 24, 197.°B uchtela, K., Arzneimittel-Forschung, 1967, 17, 591. "Hastbacka, J., and Tammisto, T., Nordisk Medicin, 1967, 77, 444. 12 Lipecz, J., and Bihler, K., Medizinische Welt, 1969, 2, 1662 13 Schmidt, G., Hippokrates, 1960, 31, 699. 14 Walther, C., Koestering, H., and Cordes, V., Arzneimittel-Forschung, 1969, 19, 75 Journal, 1975, 3, 616-618 Summary Twenty-one patients with angina pectoris were treated with adrenergic beta-receptor antagonists. Previously the resting heart rate had been used as a guide to treatment, a reduction in the rate to 55-60 beats/min without symptomatic improvement indicating failure of medical treatment. These patients were re-evaluated before coronary arteriography using the peak-exercise heart rate as an index of adrenergic beta-receptor antagonism.The dose of beta-blocking drugs was increased to produce a peak-exercise heart rate of less than 100 beats/min or a consistent rate of 100-125 beats/m...
SUMMARY In an attempt to assess the value of coronary sinus lactate estimation before and during atrial pacing for the diagnosis of obstructive coronary artery disease, 70 patients with angina were investigated in this way and by selective coronary arteriography. Thirty-five had radiologically normal coronary arteries and 35 had coronary artery disease. When the change in coronary arteriovenous lactate difference was less than 0-09 mmol/l (0.8 mg/100 ml) between the control and the peak atrial pacing sample, the coronary arteries were normal except in one patient who had distal disease of a single vessel. When the change was greater than 0-22 mmol/l (2.0 mg/100 ml) coronary artery disease was always found, and when the change was greater than 0 39 mmol/l (3.5 mg/100 ml) there was always disease of two or three vessels. Unfortunately, the presence or absence of coronary artery disease could not be predicted when the change fell between 0 09 and 0-22 mmol/l (0.8 and 2-0 mg/100 ml). Estimation of coronary sinus lactate before and during atrial pacing can thus frequently distinguish patients with normal coronary arteries from those with coronary artery disease.
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