Scintigraphic evidence that the right ventricular myocardium tolerates ischaemia better than the left ventricular myocardium

To study the incidence of right ventricular infarction and theeffect of intracoronary thrombolysis on the ischaemic rightventricular myocardium, we performed intracoronary myocardialthallium scintigraphy in 18 patients with complete occlusionof the right coronary artery who underwent intracoronary thrombolysis.In 15 of these patients, intracoronary thallium-201 and technetium-99m pyrophosphate scintigrams were performed simultaneously. All18 patients had a right ventricular thallium defect before thrombolysis,and all had new thallium uptake after thrombolysis. 17 out of18 patients had a left ventricular thallium defect before thrombolysis,but only 10 of them showed new thallium uptake after thrombolysis.14 out of 15 patients had a left ventricular technetium-99 mpyrophosphate spot after thrombolysis and some diffuse pyrophosphateaccumulation in the area of the right ventricle. In one patientpyrophosphate accumulation was found only in the area of theright ventricle. Thus, right ventricular thallium defects weredetected by intracoronary thallium scintigraphy in the majorityof patients with inferior acute myocardial infarction due toright coronary artery occlusion. Right ventricular thalliumdefects were always reversible in contrast to left ventricularthallium defects in the same patients, suggesting that rightventricular myocardium tolerates ischaemia better than leftventricular myocardium.