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Background: Several trials have been performed in the past using glucose, insulin, and potassium infusion (GIK) for the treatment of acute myocardial infarction (AMI). Because of continuing uncertainty about the potential role of this therapeutic intervention, we conducted a randomized trial to evaluate the impact of a GIK solution during the first hours of AMI., Methods and Results: Four hundred seven patients with suspected AMI admitted within 24 hours of symptoms onset were enrolled. In a ratio of 2:1, 268 patients were allocated to receive GIK (high- or low-dose) and 139 to receive control. Phlebitis and serum changes in the plasma concentration of glucose or potassium were observed more often with GIK. A trend toward a nonsignificant reduction in major and minor in-hospital events was observed in patients allocated to GIK. In 252 patients (61.9%) treated with reperfusion strategies, a statistically significant reduction in mortality (relative risk [RR] 0.34; 95% CI: 0.15 to 0.78; 2P=0.008) and a consistent trend toward fewer in-hospital events in the GIK group were observed., Conclusions: Our results confirm that a metabolic modulation strategy in the first hours of an AMI is feasible, applicable worldwide, and has mild side effects. The statistically significant mortality reduction in patients who underwent a reperfusion strategy might have important implications for the management of AMI patients. It is now essential to perform a large-scale trial to reliably determine the magnitude of benefit.

To determine whether or not the previously reported association between alcohol intake and high blood pressure is influenced by differential intake of calcium and potassium in drinkers compared with nondrinkers and to assess the magnitude of the independent contributions of alcohol, calcium, and potassium to blood pressure, these associations were evaluated in 7,011 men of Japanese descent. Categorical analyses and multiple linear regression techniques were used to test the hypotheses that alcohol, calcium, and potassium were independent predictors of blood pressure. Alcohol consumption above a threshold of approximately 20 ml/day was found to be positively, strongly, and independently correlated with systolic and diastolic pressures, and this effect was completely independent of the effects of calcium and potassium. Calcium and potassium intake were highly correlated (r = 0.59) and were inversely related to blood pressure, and their combined effect was greater than the effect of either alone. However, in the subgroup of moderate and heavier drinkers, only potassium was inversely related to blood pressure. This finding is compatible with previous reports of malabsorption and increased excretion of calcium at higher levels of alcohol intake, and it indicates that a small portion of the alcohol-induced blood pressure elevation may be mediated through calcium depletion. In the range of dietary intake in this cohort, the effect of alcohol on blood pressure was stronger than was either the separate or combined effects of calcium and potassium.

Left ventricular function was evaluated by single pass Tc-99m radionuclide ventriculography when potassium cardioplegia was combined with hypothermia. In 35 patients undergoing myocardial revascularization (3 CABG/patient) in which potassium cardioplegia at 4 degrees C was used, no patient developed a myocardial infarction either by electrocardiogram or Tc-99m pyrophosphate imaging in the postoperative period. In 22 patients, aortic cross-clamp time was greater than 60 min, and the ejection fraction by the single pass radionuclide technique was 50% preoperatively and 53% postoperatively (NS). Wall motion in the single RAO view was not worse postoperatively. No patient required any inotropic agents in the immediate postoperative period. It appears that no significant ventricular impairment occurred in the immediate postoperative period (48 to 72 hours) when potassium cardioplegia combined with hypothermia was used for a 60-minute period.

The long-term effects of cold potassium cardioplegic arrest was examined in 40 patients who underwent myocardial revascularization. Comparisons between resting ejection fraction (EF), end diastolic volume (EDV), and segmental wall motion were made between the preoperative and postoperative catheterization (mean postoperative recatheterization, 6 months). A 2.93 graft per patient ratio was found in this group of patients, with 108/117 grafts visualized at the time of recatheterization. The EF was 60% +/- 3% before surgery and 62% +/- 3% after surgery. A correlation coefficient of 0.91 was determined for the entire series. The EDV was 151 +/- 16 cc before coronary artery bypass graft (CABG) and was unchanged post CABG at an end diastolic volume of 137 +/- 15 cc. Analysis of preoperative wall motion of 33 patients demonstrated 111 depressed segments, 68 normal, and 52 hypercontractile; at recathetrization, there were 100 depressed, 66 normal, and 65 hypercontractile segments. Although there was essentially no deterioration of myocardial function for 37 out of 40 patients, three demonstrated a reduction in EF, the largest reduction being 15%. These three patients had a cardioplegic arrest time greater than 70 minutes. An inverse relationship between percent change in EF and the length of cardioplegic arrest was observed, with an r value o - 0.57 (p less than 0.01). These data suggest that prolonged cardioplegic arrest times may be associated with mild dysfunction. Cold potassium cardioplegic arrest up to 70 minutes was associated with no change in EF, EDV, or wall motion in this series of patients.