Angina with normal coronary arteriograms. Value of coronary sinus lactate estimation in diagnosis and treatment.

Abstract

Thirty-five patients with chest pain of sufficient severity to warrant coronary arteriography had normal coronary arteriograms.In each of them coronary sinus lactate was measured before and during atrial pacing.In 16 the lactate metabolism was normal as shown by a change between resting and peak pacing arteriovenous lactate difference of less than 0-09 mmol/l (0.8 mg/100 ml).Nineteen patients had abnormal lactate metabolism, the change being greater than 0-09 mmol/l (0.8 mg/100 ml).Sixteen (84%) of the group with abnormal lactate metabolism responded symptomatically to oral beta-blockade in contrast to only one patient in the normal group (P < 0.001).After 1 year all 16 patients with abnormal lactate metabolism who had responded to beta-blockade worsened when placebo was substituted.Fifteen of the 16 patients with normal lactate metabolism had become free of symptoms on no specific drug therapy; it is thus unlikely that their original pain was of cardiac origin.By estimating the coronary sinus lactate, it is, therefore, possible to divide patients with chest pain and normal coronary arteriograms into two groups.Those with pain ofnon-cardiac origin have normal lactate metabolism, are unlikely to respond to beta-blockade, and improve spontaneously.The group with abnormal lactate metabolism have genuine angina, usually respond to beta-blockade, and deteriorate when treatment is discontinued.Further observation is required to determine the prognosis of the two groups and to estimate the frequency of development of coronary artery disease.