Effect of insulin infusion on electrocardiographic findings following acute myocardial infarction: importance of glycaemic control

Clinical, Electrocardiographic, and Echocardiographic Features in Hospitalized Nonagenarians (90+): Comparison between the Genders

OBJECTIVES

We investigated the clinical, electrocardiographic, and echocardiographic determinants of the cardiac status in nonagenarian patients.

METHODS

We consecutively examined 654 Caucasian patients (232 males and 422 females) aged ≥90 years. All patients underwent clinical examination, ECG, and transthoracic echocardiography.

RESULTS

Their average age was 92.5 ± 2.5 years. Patients were predominately female of older age (p < 0.0001 and p = 0.02, respectively). A history of cardiovascular disease was present in 78.4% of the participants. One third of the patients was hospitalized for cardiovascular causes, with females being twice as many (p < 0.0001). Females showed higher levels of serum cholesterol, triglycerides, and glycemia (p < 0.0001, p< 0.0001, and p = 0.04 respectively). Sinus rhythm was detected in 65%, and atrial fibrillation in 31% of the overall population. Heart rate, PR and corrected QT (QTc) intervals, right bundle branch block (RBBB) and RBBB associated with left anterior fascicular block (LAFB) were higher in males (p < 0.0001, p = 0.036, p = 0.009, p = 0.001, and p = 0.004, respectively). Aortic root dimension, left ventricular (LV) mass index, and indexed LV systolic-diastolic volumes were higher in males (p < 0.001, p < 0.0001, p < 0.001, and p < 0.0001, respectively). Women showed fewer LV segmental kinetic disorders (p = 0009) and higher LV ejection fraction (LVEF; p< 0.0001). Hyperuricemia was positively associated with a history of cardiovascular disease (r = 0.15), glycemia (r = 19), creatininemia (r = 0.50), uremia (r = 0.51), triglycerides (r = 0.19), PR interval (r = 0.14), and left bundle branch block (r = 0.11), and inversely associated with sinus rhythm (r = -0.14) and LVEF (r = -0.17). Diabetes was positively correlated with PR and QTc intervals (r = 0.14 and r = 0.10, respectively), and RBBB with LFAB (r = 0.10), and inversely correlated with LVEF (r = -0.10).

CONCLUSIONS

We found a remarkable presence of cardiovascular risk factors, ECG, and structural alterations in hospitalized nonagenarians, which presents more commonly in males.

Glucose control in acute myocardial infarction: a pilot randomized study controlled by continuous glucose monitoring system comparing the use of insulin glargine with standard of care

BACKGROUND

This pilot study aimed to verify if glycemic control can be achieved in type 2 diabetes patients after acute myocardial infarction (AMI), using insulin glargine (iGlar) associated with regular insulin (iReg), compared with the standard intensive care unit protocol, which uses continuous insulin intravenous delivery followed by NPH insulin and iReg (St. Care).

PATIENTS AND METHODS

Patients (n=20) within 24 h of AMI were randomized to iGlar or St. Care. Therapy was guided exclusively by capillary blood glucose (CBG), but glucometric parameters were also analyzed by blinded continuous glucose monitoring system (CGMS).

RESULTS

Mean glycemia was 141±39 mg/dL for St. Care and 132±42 mg/dL for iGlar by CBG or 138±35 mg/dL for St. Care and 129±34 mg/dL for iGlar by CGMS. Percentage of time in range (80-180 mg/dL) by CGMS was 73±18% for iGlar and 77±11% for St. Care. No severe hypoglycemia (≤40 mg/dL) was detected by CBG, but CGMS indicated 11 (St. Care) and seven (iGlar) excursions in four subjects from each group, mostly in sulfonylurea users (six of eight patients).

CONCLUSIONS

This pilot study suggests that equivalent glycemic control without increase in severe hyperglycemia may be achieved using iGlar with background iReg. Data outputs were controlled by both CBG and CGMS measurements in a real-life setting to ensure reliability. Based on CGMS measurements, there were significant numbers of glycemic excursions outside of the target range. However, this was not detected by CBG. In addition, the data indicate that previous use of sulfonylurea may be a potential major risk factor for severe hypoglycemia irrespective of the type of insulin treatment.

High-dose insulin in experimental myocardial infarction in rabbits: protection against effects of hyperglycaemia

INTRODUCTION

Hyperglycaemia at the time of acute myocardial infarction (AMI) is a predictor of survival and is associated with increased mortality and morbidity in patients with or without diabetes mellitus. On the other hand, insulin has been shown to reduce myocardial injury in experimental studies but its benefits have not been confirmed in clinical studies.

METHODS

The isolated perfused heart model was used to examine the direct effect of incremental doses of insulin and varying degrees of hyperglycaemia on infarct size and cardiomyocyte apoptosis in rabbit hearts. The rabbit hearts were subjected to 30-min ischaemia and 2.5-h reperfusion.

RESULTS

Insulin, given alone just before reperfusion, dramatically reduced infarct size in a dose-dependent manner (75-300 μU/ml) during experimental myocardial infarction (46%±2% to 10.9%±3%, P<.001). Acutely elevated glucose levels (33 mmol/L) induced a significantly greater infarct size and cardiomyocyte apoptosis compared to hearts subjected to normal glucose levels. On the other hand, high-dose insulin (300 μU/ml) given 5 min before reperfusion attenuated the extent of infarction and reduced apoptosis in hearts that were exposed to high glucose levels.

CONCLUSION

Acutely elevated levels of glucose induced larger infarct area during ischaemia-reperfusion, and this is mediated through proapoptotic pathways. Insulin, when given just before reperfusion, confers cardioprotection in a dose-dependent manner and reverses the detrimental effect of acute hyperglycaemia. High-dose insulin as well as maintaining normoglycaemia remain important factors that improve outcomes following myocardial infarction.