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Myocardial release of citrate and lactate during atrial pacing-induced angina pectoris
Insights
Plasma citrate differences in coronary artery disease (CAD) patients during pacing recovery indicate myocardial ischemia. This citrate wash-out is a more sensitive marker than lactate release for detecting heart ischemia.
Area of Science:
- Cardiology
- Biochemistry
- Medical Diagnostics
Background:
- Coronary artery disease (CAD) poses significant health risks.
- Assessing myocardial ischemia is crucial for patient management.
- Current markers for ischemia, like lactate release, have limitations.
Purpose of the Study:
- To investigate arterio-coronary sinus (A-Cs) plasma differences of metabolites during pacing.
- To evaluate plasma citrate as a potential marker for myocardial ischemia in CAD patients.
- To compare the sensitivity of plasma citrate changes versus lactate release in detecting ischemia.
Main Methods:
- Measured A-Cs plasma differences of citrate, glucose, free fatty acids, and lactate.
- Included 19 CAD patients and 8 control subjects.
- Subjects underwent atrial pacing to induce potential ischemia.
Main Results:
- In CAD patients, A-Cs plasma citrate differences became increasingly negative during recovery from pacing.
- Lactate producers (LP) showed a significant negative shift (-5 vs. -12 mumol/l), as did lactate non-producers (LNP) (-6 vs. -8 mumol/l).
- Control subjects showed an inverse change in citrate difference (-8 vs. -2 mumol/l).
Conclusions:
- An increasingly negative A-Cs plasma citrate difference during recovery reflects citrate washout from ischemic heart cells.
- Plasma citrate changes appear to be a more sensitive marker of myocardial ischemia than lactate release in humans.
- This finding suggests a novel diagnostic approach for detecting heart ischemia.
Abstract:
Arterio-coronary sinus (A-Cs) differences of plasma citrate, glucose, free fatty acids and blood lactate were measured in 19 patients with coronary artery disease (CAD) and in eight control subjects exposed to atrial pacing. Among patients with CAD 11 showed a myocardial release of lactate during pacing (lactate producers, LP) while myocardial lactate extraction was unchanged in the remaining eight patients (lactate non-producers, LNP). In patients with CAD, (A-Cs) plasma citrate differences became increasingly negative during recovery from pacing, values at rest and at 3-5 min of recovery were: -5 +/- 2 mumol/l (mean +/- SD) vs. -12 +/- 5 mumol/l in LP (P less than 0.001) and -6 +/- 3 mumol/l vs. -8 +/- 4 mumol/l in LNP (P less than 0.01). In controls, (A-Cs) citrate difference varied inversely, from -8 +/- 4 mumol/l at rest to -2 +/- 4 mumol/l at 3-5 min of recovery (P less than 0.001). An increasingly negative (A-Cs) plasma citrate difference during recovery from pacing-induced angina pectoris is suggested to reflect a wash-out of accumulated citrate from ischaemic heart cells; and is proposed as a more sensitive marker of ischaemia in man than a myocardial release of lactate.