Right Ventricular Wall “Ischemia” Findings Using a Dual Isotope Protocol

A 74-year-old man with a history of diabetes and arterial hypertension, presented with right ventricular failure, remarkable jugular venous distension, hepatomegaly, and swelling of the lower extremities. He was complaining of atypical chest pain and was referred for an echocardiogram and a myocardial perfusion SPECT imaging study. The echocardiogram showed normal left ventricular function with a dilated right atrium and right ventricle, severe tricuspid regurgitation, pulmonary hypertension, and an atrial septal defect with bidirectional shunt. The SPECT images showed normal left ventricular function with no areas of induced ischemia but an impressive right ventricle with severe dilatation and hypertrophy. A right ventricular “perfusion abnormality,” consistent with ischemic changes, seen on stress but less evident on rest images was demonstrated on the dual isotope (Tl-201 rest/Tc-99m MIBI stress) protocol but not seen on the single isotope study (rest/stressTc-99m MIBI). Coronary angiogram showed diffuse coronary atherosclerosis but without significant obstruction.