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- Svedjeholm, Rolf, et al.
(författare)
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Are electrocardiographic Q-wave criteria reliable for diagnosis of perioperative myocardial infarction after coronary surgery?
- 1998
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Ingår i: European Journal of Cardio-Thoracic Surgery. - 1010-7940 .- 1873-734X. ; 13:6, s. 655-661
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Tidskriftsartikel (refereegranskat)abstract
- Objective: A major assumption in cardiovascular medicine is that Q-waves on the electrocardiogram indicate major myocardial tissue damage. The appearance of a new Q-wave has therefore been considered the most reliable criterion for diagnosis of perioperative myocardial infarction (PMI) in cardiac surgery. In a study, originally intended to evaluate troponin-T as a marker of PMI, analysis of our data aroused the need to address the reliability of Q-wave criteria for diagnosis of PMI.Methods: In 302 consecutive patients undergoing coronary surgery, Q-wave and other electrocardiogram (ECG) criteria were compared with biochemical markers of myocardial injury and the postoperative course. All ECGs were analysed by a cardiologist blinded to the biochemical analyses and the clinical course.Results: The incidence of positive Q-wave criteria was 8.1%. Combined biochemical (CK-MB≥70 μg/l) and Q-wave criteria were found in 1.0%. Patients with new Q-waves did not have CK-MB or troponin-T levels significantly different from those without Q-waves. More than 25% of the Q-waves were associated with plasma troponin-T below the reference level (<0.2 μg/l) on the fourth postoperative day. Q-wave criteria alone did not influence the postoperative course. In contrast, biochemical markers correlated with clinical outcome.Conclusions: The majority of Q-waves appearing after coronary surgery were not associated with major myocardial tissue damage, and according to troponin-T one-fourth of the Q-waves were not associated with myocardial necrosis. Furthermore, the appearance of Q-waves had little influence on short term clinical outcome. Therefore, the use of Q-wave criteria as the gold standard for diagnosis of PMI may have to be questioned.
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- Svedjeholm, Rolf, et al.
(författare)
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Metabolic and hemodynamic effects of intravenous glutamate infusion early after coronary operations
- 1996
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Ingår i: Journal of Thoracic and Cardiovascular Surgery. - 0022-5223 .- 1097-685X. ; 112:6, s. 1468-77
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Tidskriftsartikel (refereegranskat)abstract
- Amino acids, particularly glutamate, have been proposed to play an important role in the recovery of cardiac oxidative metabolism after ischemia. In this investigation, the metabolic and hemodynamic effects of glutamate infusion after coronary operations were studied. From 220 to 240 ml 0.1 mol/L l-glutamic acid solution was infused in 10 patients during 1 hour starting 2 hours after operation. A control group of 10 patients received an infusion of 240 ml saline solution. During glutamate infusion, there were significant increases in the uptake of glutamate (from 0.7 +/- 0.2 micromol/min in the basal state to a peak of 5.7 +/- 1.2 micromol/min at 20 minutes) and lactate (from 4.9 +/- 2.0 micromol/min in the basal state to 14.1 +/- 4.4 micromol/min at 60 minutes; p < 0.01), whereas the uptake and release of other substrates remained essentially unaffected. Arterial glutamate levels (in whole blood) increased from 103 +/- 10 micromol/L to 394 +/- 20 micromol/L at 60 minutes. Thirty minutes after discontinuation of the glutamate infusion, arterial levels had decreased to 129 +/- 17 micromol/L. The markedly improved utilization of lactate and the unchanged release of alanine together suggest that the oxidative metabolism of the heart was stimulated by glutamate. The metabolic changes were associated with improved myocardial performance. Left ventricular stroke work index increased from 26.8 +/- 2.1 gm x beat(-1) x m(-2) body surface area to 31.3 +/- 3.1 gm x beat(-1) x m(-2) body surface area during glutamate infusion. Metabolic support with amino acids may provide a means to improve recovery of metabolic and hemodynamic function of the heart early after cardiac operations.
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- Vanhanen, Ingemar, et al.
(författare)
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Assessment of myocardial glutamate requirements early after coronary artery bypass surgery
- 1998
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Ingår i: Scandinavian Cardiovascular Journal. - : Informa UK Limited. - 1401-7431 .- 1651-2006. ; 32:3, s. 145-152
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Tidskriftsartikel (refereegranskat)abstract
- Glutamate is an important substrate for the intermediary metabolism of the heart, particularly in association with ischemia. Early after coronary artery bypass surgery (CABG) myocardial uptake of glutamate seems to be limited by substrate availability (arterial levels). However, glutamate is not an innocuous substrate. As arterial levels of glutamate are important both for myocardial uptake and adverse effects, an attempt was made to determine a minimum dose of glutamate sufficient to supply the needs of the heart after CABG. Ten patients received and infusion of 220-240 ml of 0.1 M L-glutamic acid solution at varying rates during two 30-min periods, starting 2 h after uncomplicated elective CABG. Intravenous glutamate infusion caused a dose-dependent linear increase in arterial glutamate and an increased myocardial uptake of glutamate. However, myocardial uptake of glutamate correlated with arterial levels only at lower infusion rates. Although maximal peak uptake in individual patients (6.6 ± 1.1 μmol/min) occurred at an average increase of arterial whole blood glutamate of 172 ± 34 μmol/L, the greatest impact on myocardial glutamate uptake was achieved by increasing arterial whole blood glutamate by less than 100 μmol/L. This implies that an infusion rate of 30-40 mg glutamate/kg BW/h could suffice to achieve a maximal or near maximal myocardial glutamate uptake in most patients after CABG. The adequacy of this dosage remains to be confirmed in high-risk patients.
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