Glucose-Insulin-Potassium (GIP) as a tool for prevention and treatment of myocardial ischaemia

Recent times are witnessing a resurge of metabolic interventions in order to preserve myocardial tissue and improve cardiac function after hypoxic or ischaemic events. The basic principle of this therapeutic approach which differs completely from surgical and radiological revascularisation techniques as well as from direct pharmacologic stimulation of contractility by catecholamines or phosphodiesterase inhibitors is illustrated by the effect of glucose-insulin-potassium (GIK) infusions. Physiology of myocardial metabolism and its pathophysiology in hypoxia and ischaemia are discussed in their relation to the administration of GIK with its main effect of switching from the preferential fat oxydation under normal conditions to a greater percentage of glucose utilisation. GIK can be used in therapeutic intention after an ischaemic insult (myocardial infarction, preoperatively) or as a preventive measure (pre-ischaemic) e.g. prior to a planned intervention (cardiac surgery). GIK improves myocardial energy supply, economizes oxygen utilisation, stabilizes hypoxic cells, diminishes the area of infarction, and increases myocardial contractility and coronary blood flow. Both in controlled trials and in metaanalyses, GIK administration resulted in reduced mortality from myocardial infarction. In conclusion, metabolic interventions present a promising alternative or adjunctive therapeutic tool for the restitution or maintenance of myocardial integrity and cardiac function impaired or threatened by ischaemic events.