In a total of 12 pigs studied (6 Dpigs; 6 Cpigs), 83% of the Dpigs (5 out of 6) and 17% of the Cpigs (1 out of 6) there developed a sustained ventricular tachyarrhythmias within 5 minutes after the infusion of DADLE or sham control into the localized segment of myocardium (Table 1).
Nonetheless, it is important to note that the average DP/dt (an indicator of contractility) fell significantly during the occlusion and infusion period for the Cpigs (-20%) while it remained stable for the Dpigs receiving DADLE during this same period.
This is in stark contrast to prior evidence demonstrating a lack of arrhythmogenesis and no effect on the electrocardiogram during coronary occlusion when DADLE is infused systemically and has the opportunity for global effects (5).
It is possible that the increased contractility and heart rate also increased the basal myocardial oxygen demand in the DADLE group and resulted in relatively more ischemia during the occlusion period.
If the effects of the DADLE were present within the whole heart then this dispersion would be less likely to develop.
However, the overwhelming propensity of the dysrhythmic events to occur after the DADLE infusion, as opposed to the control period, makes that consideration very improbable.
It is well recognized that DADLE may be protective against ischemia in a variety of organs other than the heart.