Abstract
Stunned myocardium of right ventricle was studied by radionuclide angiography (RNA) and Thallium myocardial scintigraphy (TL) in 39 patients with inferior myocardial infarction with and without right ventricular myocardial infarction (RVMI). RNA was performed within 1 week of the onset (acute phase) and after 1 month, when exercise cardiac scintigraphy (EX-TL) was also performed. The ejection fraction (EF) of each ventricle calculated from RNA and the phase and amplitude evaluated visually and quantitatively by Fourier analysis were compared between the acute phase and 1 month after the onset of myocardial infarction. The degree of visualization of right ventricle was examined in EX-TL 1 month after the oneset. (1) In RNA obtained in the acute myocardial infarction, abnormalities in the right ventricle (delayed phase or low amplitude image) were observed in 18 (46%) but not in 21 (54%) of the 39 patients (N group). Of those 18 patients, the abnormalities in the right ventricle alleviated in 11 (RVMI-A group) but persisted in 7 (RVMI-B group) in RNA obtained 1 month after the onset. (2) In the acute phase, the right ventricular ejection fraction (RVEF) was 39.4±10.4% in N group, 30.8±5.3% in RVMI-A group, and 29.68.9% in RVMI-B group, with significant differences between N group and the other two groups (P<0.05) but no significant difference between RVMI-A and RVMI-B groups. (3) After 1 month. RVEF was 40.1±10.1% in N group. 42.2±8.4% in RVMI-A group, and 32.2±9.8% in RVMI-B group, being improved in RVMI-A group and showing a significant difference as compared with RVMI-B group (p<0.05). (4) In EX-TL of RVMI-A group, the right ventricle was visible although the uptake of TL was reduced in the en-tire right ventricle. In RVMI-B group, only part of the right ventricular free wall was visible with defects in the other areas of right ventricle. The sign of RVMI showed improvements in many of the patients after the acute phase, and their condition was considered to have been so-called stunned myocardium, which is a complex of symptoms of reversible myocardial ischemia, rather than RVMI.
