This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by CHIONG, M. A. Articles by PARKER, J. O. Search for Related Content PubMed PubMed Citation Articles by CHIONG, M. A. Articles by PARKER, J. O.

(Circulation. 1974;49:283.)
© 1974 American Heart Association, Inc.

---

Myocardial Balance of Inorganic Phosphate and Enzymes in Man

Effects of Tachycardia and Ischemia

MIGUEL A. CHIONG M.D., PH.D.¹; ROXROY WEST M.D.¹; JOHN O. PARKER M.D.¹

¹ From the Division of Cardiology, Department of Medicine, Queen's University and Kingston General Hospital, Kingston, Ontario, Canada.

The effects of atrial pacing on the cardiac balance of inorganic phosphate (P_i) were studied during control, atrial pacing, and recovery periods in 29 patients. Group A (n = 18) who had roentgenographically demonstrated coronary artery disease (CAD) developed angina during pacing, and showed mean myocardial lactate (L) production, abnormal left ventricular end-diastolic pressure (LVEDP) and ST segment depression. Group NA (n = 11), composed of six patients with CAD and five subjects with no demonstrable cardiac disease, had normal lactate metabolism, LVEDP, and ST segments during pacing. In addition, blood levels of two enzymes were determined: creatine phosphokinase (CPK) in nine patients of Group A and six patients of Group NA, and glutamic oxaloacetic transaminase (GOT) in eight patients of each group.

During control, small uptake of P_i was observed in both groups. During pacing, Group A showed first a fall and then abolition of mean P_i uptake, and during the early recovery period, a small loss of this ion was observed. Although there was a good correlation between L and P_i uptakes (r = 0.86, P < 0.001) throughout the study, P_i loss, which occurred in 55% of patients in Group A, appeared to be a less reliable index of myocardial anaerobiosis than L production, which occurred in 72%. No consistent changes in P_i balance were observed in Group NA. The only significant enzymatic change was the small but sudden and significant rise of mean CPK levels in coronary sinus (CS) blood above the arterial levels in five patients of Group A during the first 6 min of pacing. These data show that during pacing-induced angina the human heart loses P_i. In addition, these preliminary observations on the CS CPK levels during pacing in the angina patients suggest that the stress of tachycardia and ischemia may facilitate the escape of this enzyme from the heart.

Key Words: Atrial pacing • Creatine phosphokinase • Left ventricular end-diastolic pressure • Coronary artery disease • Angina • ST segments • Myocardial anaerobiosis • Glutamic oxaloacetic transaminase • Lactate

Submitted on July 2, 1973
Accepted on September 4, 1973

This article has been cited by other articles:

				L. Coudrey The Troponins Arch Intern Med, June 8, 1998; 158(11): 1173 - 1180. [Full Text] [PDF]

				A. E. Abdelmeguid and E. J. Topol The Myth of the Myocardial `Infarctlet' During Percutaneous Coronary Revascularization Procedures Circulation, December 15, 1996; 94(12): 3369 - 3375. [Full Text]