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Effects of glucose-insulin-potassium infusion on chronic ischaemic left ventricular dysfunction
V K Khoury1, B Haluska, J Prins
1University of Queensland, Brisbane, Queensland, Australia.
Insights
Glucose-insulin-potassium (GIK) infusion improves cardiac function in patients with chronic ischaemic left ventricular dysfunction. This benefit is linked to viable myocardium and enhances wall motion and myocardial velocity.
Area of Science:
- Cardiology
- Cardiovascular Research
- Ischaemic Heart Disease
Background:
- Glucose-insulin-potassium (GIK) infusion is known to improve cardiac function during acute ischaemia.
- Chronic ischaemic left ventricular dysfunction poses a significant clinical challenge.
Purpose of the Study:
- To evaluate the efficacy of GIK infusion in patients with chronic ischaemic left ventricular dysfunction.
- To determine if the benefits of GIK are associated with the presence and characteristics of viable myocardium.
Main Methods:
- 30 patients with chronic ischaemic left ventricular dysfunction underwent dobutamine echocardiography.
- A four-hour GIK infusion was administered, with segmental and global cardiac function assessed.
- Wall motion score index, peak systolic velocity, left ventricular volume, and ejection fraction were measured.
Main Results:
- GIK infusion significantly improved wall motion score index and peak systolic velocity.
- Improvements in wall motion were predominantly observed in myocardial segments identified as viable by dobutamine echocardiography.
- End systolic volume improved in patients with viable myocardium, independent of haemodynamic changes or catecholamine levels.
Conclusions:
- GIK infusion offers benefits for patients with chronic ischaemic left ventricular dysfunction and viable myocardium.
- The positive effects on cardiac function, including improved wall motion and myocardial velocity, are independent of haemodynamic alterations.
- The study highlights the potential of GIK as a therapeutic option for specific patient populations with heart dysfunction.
Background:
Glucose-insulin-potassium (GIK) infusion improves cardiac function and outcome during acute ischaemia.
Objective:
To determine whether GIK infusion benefits patients with chronic ischaemic left ventricular dysfunction, and if so whether this is related to the presence and nature of viable myocardium.
Methods:
30 patients with chronic ischaemic left ventricular dysfunction had dobutamine echocardiography and were given a four hour infusion of GIK. Segmental responses were quantified by improvement in wall motion score index (WMSI) and peak systolic velocity using tissue Doppler. Global responses were assessed by left ventricular volume and ejection fraction, measured using a three dimensional reconstruction. Myocardial perfusion was determined in 15 patients using contrast echocardiography.
Results:
WMSI (mean (SD)) improved with dobutamine (from 1.8 (0.4) to 1.6 (0.4), p < 0.001) and with GIK (from 1.8 (0.4) to 1.7 (0.4), p < 0.001); there was a similar increment for both. Improvement in wall motion score with GIK was observed in 55% of the 62 segments classed as viable by dobutamine echocardiography, and in 5% of 162 classed as non-viable. There was an increment in peak systolic velocity after both dobutamine echocardiography (from 2.5 (1.8) to 3.2 (2.2) cm/s, p < 0.01) and GIK (from 3.0 (1.6) to 3.5 (1.7) cm/s, p < 0.001). The GIK effects were not mediated by changes in pulse, mean arterial pressure, lactate, or catecholamines, nor did they correlate with myocardial perfusion. End systolic volume improved after GIK (p = 0.03), but only in 25 patients who had viable myocardium on dobutamine echocardiography.
Conclusions:
In patients with viable myocardium and chronic left ventricular dysfunction, GIK improves wall motion score, myocardial velocity, and end systolic volume, independent of effects on haemodynamics or catecholamines. The response to GIK is observed in areas of normal and abnormal perfusion assessed by contrast echocardiography.