Myocardial ischemia due to vasospasm of small coronary arteries detected by methylergometrine maleate stress myocardial scintigraphy

BACKGROUND

Recently, several case reports have implicated vasospasm of small coronary arteries in vasospastic angina pectoris. Vasospasm of small coronary arteries was also considered from angiographic findings in patients with atypical chest pain. In Syrian hamster, vasospasm in small coronary arteries was considered to be the cause of dilated cardiomyopathy.

HYPOTHESIS

This study was undertaken to determine whether vasospasm in small coronary arteries can be induced by methylergometrine maleate stress thallium-201 (201Tl) myocardial scintigraphy.

METHODS

Twenty-five patients with chest pain, all of whom had intact coronary arteries, were studied. After intracoronary methylergometrine maleate injection, coronary arteriograms also looked normal in all cases. Thallium-201 myocardial scintigraphy was carried out immediately after intracoronary methylergometrine maleate injection in four patients with chest pain. In the remaining 21 patients with chest pain, methylergometrine maleate was given intravenously within up to 2 weeks before 201Tl myocardial scintigraphy.

RESULTS

In the intracoronary injection study, one patient had chest discomfort after methylergometrine maleate injection, and ST-segment elevation was observed on electrocardiogram (ECG). Of the 21 patients with chest pain, 11 patients felt angina-like chest pain after intravenous injection of methylergometrine maleate, but their ECGs showed no ischemic changes. Stress 201Tl myocardial scintigrams showed methylergometrine maleate-induced perfusion defects with complete redistribution in 3 of 4 patients in the intracoronary injection study and in 12 of 21 patients in the intravenous injection study. These findings suggest that vasospasm in small coronary arteries caused myocardial ischemia in 15 of 25 patients (60%) with chest pain.

CONCLUSION

Vasospasm in small coronary arteries may be involved in the myocardial ischemia of some patients with chest pain who do not show any large coronary artery vasospasm.

Diagnosis of cardiac sarcoidosis and evaluation of the effects of steroid therapy by gadolinium-DTPA-enhanced magnetic resonance imaging

BACKGROUND

Cardiac involvement is an important prognostic factor in patients with sarcoidosis. In this study, we evaluated the usefulness of gadolinium-DTPA (diethylene triamine pentaacetic acid)-enhanced magnetic resonance imaging (Gd-MRI) for diagnosing cardiac sarcoidosis and evaluating the effects of steroid therapy.

METHODS

Sixteen patients with sarcoidosis diagnosed by histology or by Japanese Ministry of Health and Welfare criteria for cardiac sarcoidosis underwent Gd-MRI with a 1.5-Tesla superconducting magnet system using a T1-weighted spin-echo sequence.

RESULTS

Gd-MRI showed localized enhancement of signal intensity, indicating interstitial edema, in the left ventricle in 8 of the 16 patients. Two patients with enhancement also had thinning of the left ventricular septal wall. After 1 month of prednisolone therapy (60 mg every other day or 30 to 40 mg every day), the localized high-intensity signals were markedly diminished in all 8 patients.

CONCLUSIONS

Images of the heart obtained by Gd-MRI may reflect active inflammation with interstitial edema in patients with sarcoidosis. Gd-MRI may be a useful noninvasive method for early detection of cardiac sarcoidosis and for evaluating the effects of steroid therapy.

A probable relationship between an endogenous digitalis-like substance and concentric cardiac hypertrophy in primary aldosteronism

A 44-year-old woman was admitted to our hospital due to severe hypertension. An electrocardiogram (ECG) and an echocardiogram showed severe left ventricular hypertrophy. Her plasma aldosterone level was elevated. Magnetic resonance imaging revealed a small mass in the right adrenal gland. Before removal of the tumor, plasma endogenous digitalis-like substance (EDLS) levels were elevated. After removal of the tumor, EDLS levels quickly returned to the normal level. A series of echocardiograms and ECGs over a 6- year period after removal of the tumor showed marked regression of cardiac hypertrophy. These findings suggest that EDLS may be closely related to the development of concentric cardiac hypertrophy in primary aldosteronism.

[Changes in gadolinium-DTPA enhanced magnetic resonance signal intensity ratio in hypertrophic cardiomyopathy]

Serial gadolinium-diethylene-triamine-pentaacetic acid (Gd-DTPA) enhanced magnetic resonance (MR) signal intensity ratios were measured in 6 normal subjects and 20 hypertrophic cardiomyopathy (HCM) patients to try to differentiate normal from disorganized myocardial tissue. Images were obtained at 10-minute intervals 5-60 minutes after Gd-DTPA (0.1 mmol/kg) injection. The signal intensity ratio (myocardial signal intensity/skeletal muscle signal intensity) was measured at both hypertropic and nonhypertrophic regions in each image at the apex and mid-ventricular levels. The signal intensity ratio was standardized to compare each case. Hypertrophic myocardium was classified into two types. Type I in 11 of 20 patients was visualized as a homogeneous image, while type II in the other 9 patients was revealed as a mixed isointensity and high intensity area. The peak value of the standardized signal intensity ratio at the apex level was 1.28 +/- 0.09 in HCM patients and 1.23 +/- 0.06 in normal subjects, and at the mid ventricular level was 1.26 +/- 0.07 in hypertrophic regions, 1.17 +/- 0.12 in non-hypertrophic regions, and 1.16 +/- 0.07 in normal subjects. Thirty minutes after Gd injection, the standardized signal intensity ratio at the apex level was 1.21 +/- 0.08 in HCM patients and 1.07 +/- 0.08 in normal subjects, and those at the mid ventricular level was 1.20 +/- 0.09 in hypertrophic regions, 1.11 +/- 0.11 in non-hypertrophic regions, and 1.04 +/- 0.06 in normal subjects. The delayed decay of the signal intensity ratio and high signal intensity ratio in Gd-DTPA enhanced MR images are useful in myocardial tissue characterization in hypertrophic cardiomyopathy.

Evaluating coronary reperfusion during acute myocardial infarction in a canine model by gadolinium-DTPA-enhanced magnetic resonance imaging

In previous studies, magnetic resonance imaging (MRI) using contrast agents was found to be useful in distinguishing reperfused infarcts from nonreperfused infarcts. However, there have been only a few detailed studies using consecutive MR images for the assessment of myocardial reperfusion during an acute myocardial infarction and also no studies have been performed using a percutaneous transluminal coronary occlusion model (closed chest model). We induced acute myocardial infarction in dogs by occluding and then reperfusing the coronary artery with a balloon catheter. ECG-gated MR images were taken using the spin-echo technique before and after Gd-DTPA injection during both coronary artery occlusion and after reperfusion. We defined the intensity ratio (IR) as the signal intensity at the ischemic area divided by that at the nonischemic area on MR images and compared each image by the IR. Without Gd-DTPA, there was no difference between infarcted and normally perfused myocardium. Infarcted myocardium had a low signal intensity (IR = 0.68 +/- 0.14) soon after Gd-DTPA injection. This difference diminished with time. After reperfusion the infarcted myocardium had a high signal intensity (IR:1.76 +/- 0.34). We conclude that Gd-DTPA- enhanced MRI can distinguish reperfused from nonreperfused infarcts soon after Gd-DTPA administration.

Angina pectoris due to possible vasospasm of small coronary arteries

Recently, the presence of vasospasm in small coronary arteries is speculated in animals and humans. A 40-year-old female patient complained of chest pain at rest. Left ventriculogram showed normal wall motions. Left and right coronary arteries were also normal. After methylergometrine maleate was selectively administered to a right coronary artery, she complained of chest pain, and ST-segment elevation was detected in leads II, III, and aVF of ECG. Right coronary arteriography was performed immediately, but no coronary stenosis was found. The next day, methylergometrine maleate was again administered intravenously and the patient complained of chest pain, but no ischemic changes were observed in ECG. Thallium-201 myocardial scintigraphy followed immediately. Apical perfusion defect was detected in stress image. In the delayed image, it showed complete redistribution. Three days later, catheterization and scintigraphy were performed at the same time. When methylergometrine maleate was administered to the left coronary artery, she complained of chest pain within a few minutes of the injection; however, ECG remained unchanged. 201Tl myocardial scintigraphy was performed immediately. In the stress image, it showed apical perfusion defect as shown in the intravenous methylergometrine maleate injection study. It also showed complete redistribution in the delayed image. Apical perfusion defect can be attributed to myocardial ischemia of left coronary artery, which are too small to be detected by conventional coronary arteriography. Vasospasm in small coronary arteries may be involved in this phenomenon.