Is there a specific role for technetium-99m sestaMIBI in the assessment of cardiac arrhythmias?

In a small number of patients, cardiac arrhythmias are treated by transcoronary chemical ablation [1, 2]. Selective intracoronary injection of low amounts of pure ethanol results in permanent damage of the myocardial cells, being the substrate of the arrhythmia. Destroying the substrate can, however, result in deterioration of left ventricular function, especially in patients with ventricular tachycardia after myocardial infarction and a pre-existing low ejection fraction. However, assessment of the presence of viable tissue in and around infarcted areas is very difficult. We have studied the value of selective injections of technetium-99m (Tc-99m) sestaMIBI into main coronary arteries and into small arteries providing blood supply to the substrate of cardiac arrhythmias to detect the flow areas and to estimate the area at risk for chemical ablation. In a previous study [3, 4], we demonstrated that Tc-99m sestaMIBI is able to detect short episodes of ischemia, without the need for studying the patient immediately after injection of the radioactive tracer, which obviously is a prerequisite, when the nuclear agent is administered in the catheterization laboratory. The first part of the study was performed to determine whether intracoronary injection of Tc-99m sestaMIBI could demonstrate the flow area of the myocardium perfused by that artery. In the second part, we studied the value of selective injection of Tc-99m sestaMIBI into the artery providing blood supply to the substrate of the arrhythmia.