Yasuo Futagami

Serial change of iodine-123 metaiodobenzylguanidine (MIBG) myocardial concentration in patients with dilated cardiomyopathy

Serial change of the metaiodobenzylguanidine iodine-123 (123I-MIBG) myocardial concentration was investigated in patients with dilated cardiomyopathy (DCM). Eight DCM patients and 6 control subjects were examined. After the injection of thallium-201 and 123I-MIBG, planar chest images were obtained simultaneously for both tracers in every 30–60 min over 5 h. Serial changes of myocardial uptake ratio (MUR) were compared for both tracers. In DCM, the initial MUR of 123I-MIBG did not differ significantly from that of the controls. The washout of 123I-MIBG from the myocardium, however, was significantly increased in DCM. In particular, the decrease in the early phase (15–45 min) was significantly larger in DCM than in the controls (21.2%±7.5% vs. 5.3%±4.0%, P <0.01), showing a significant negative correlation with the left ventricular ejection fraction (r = −0.72 P < 0.05). For 201TI, neither the initial MUR nor the washout rate different significantly between the two. Thus, an early rapid decrease of the 123I-MIBG myocardial concentration might characterize DCM and reflect the severity of this disease.

Isolated Congenital Left Ventricular Diverticulum in an Adult: A Case Report

A sixty-three-year-old man presented himself with atrial flutter and congestive heart failure. Cardiac catheterization revealed that left ventricular diverticulum was located on the anterobasal wall with narrow connection to the left ventricular cavity. Coronary angiography revealed normal coronary arteries. The patient had been asymptomatic until adult life with no other thoracoabdominal or cardiac anomalies. This is an extremely rare finding in the adult population.

Exercise-induced coronary spasm: comparison of treadmill and bicycle exercise in patients with vasospastic angina.

Background We investigated whether exercise-induced coronary spasms are influenced by the different exercise modes.Methods We compared ischaemic ECG responses in 67 patients with vasospastic angina who underwent both treadmill and bicycle ergometer exercise and also coronary angiography.Results ECG ST-segment elevation was provoked more frequently during treadmill exercise than it was during bicycle exercise (19 versus 9%, P<0.05). Of 45 patients without significant coronary stenosis (coronary artery luminal diameter narrowing < 75%), 19 patients manifested ST-segment depression during treadmill exercise, whereas only seven patients did during bicycle exercise (42 versus 16%, P<0.01). All patients with ST-segment elevation or depression during bicycle ergometer exercise also had ST-segment changes during treadmill exercise. Although higher systemic blood pressure levels and lower heart rates were found during bicycle exercise compared with during treadmill exercise, the pressure-rate products at peak exercise did not differ between the two exercise tests.Conclusions It seems that treadmill and bicycle exercise are different stressors in patients with vasospastic angina, and that coronary spasms are provoked more frequently during treadmill exercise than they are during bicycle exercise. The cause of this difference is not known, but it may be related in part to the difference in systemic haemodynamic or neurohumoral response.

Incidence and Clinical Course of Right Ventricular Infarction: Assessment with Radionuclide Ventriculography

The incidence and prognosis of right ventricular infarction were studied by radionuclide ventriculography (RNV) in 50 consecutive cases of acute myocardial infarction. RNV was performed within thirty-six hours of symptoms and one month after onset. Right ventricular infarction was absent in all 25 patients with anterior infarction. It was found in 15 of the 25 patients with inferior infarction, accompanied by a marked reduction in right ventricular ejection fraction (28 ± 8%), but was notably alleviated one month later with normalization of right ventricular ejection fraction (39 ± 7%) and wall motion. These phenomena seem to be specific in right ventricular infarction.

Dipyridamole radionuclide ventriculography in patients with coronary artery disease : comparison with ergometer exercise

Intravenous administration of dipyridamole during radionuclide ventriculog raphy (RNV) was performed in 26 consecutive patients with symptomatic coro nary artery disease. The authors compared the results of dipyridamole-RNV with those of ergometer exercise-RNV in detecting myocardial ischemia. During exercise, ST depression, regional wall motion (RWM) abnormalities, and de creased left ventricular ejection fraction (LVEF) were observed in 21 (81%), 23 (88%), and 20 (77%) patients, respectively. However, after intravenous di pyridamole, ST depression, RWM abnormalities, and decreased LVEF were observed in 14 (54%), 15 (58%), and 2 (8%) patients, respectively. Although LVEF usually decreases during myocardial ischemia, LVEF did not decrease (57 ± 11% to 58 ± 10%), even in patients with ST depression, after intravenous dipyridamole. Maintained left ventricular ejection fraction is considered to be a hemodynamic effect of the potent arterial vasodilatation induced by di pyridamole. These results from dipyridamole-RNV in myocardial ischemia seem to con flict with the results from dipyridamole-thallium studies carried out to deter mine the capacity to detect coronary artery disease. Unknown mechanisms of dipyridamole other than the coronary steal phenomenon may be operative in the genesis of myocardial ischemia.