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SUMARYTo determine the clinical significance of ST-segment depression observed in paroxysmal supraventricular tachycardia (PSVT), we evaluated the 12-lead electrocardiogram (ECG) during spontaneous PSVT in 54 patients (27 men and 27 women: mean ageSD; 4718 years), who came to our clinic for the treatment of PSVT. Coronary angiography was performed in 16 patients (16 to 74 years; mean=5018) and treadmill exercise testing was performed in 21 patients. A cardiac electrophysiological study was carried out in 24 patients. During PSVT, ST-segment score was calculated as the sum of the ST-segment depression in 12 leads. The correlations between the ST-segment score, PSVT rate and age of the patient were analyzed as follows: The most significant positive correlation was observed between the ST-segment score and the PSVT rate (r=0.615, p<0.000001). The next most significant correlation was found between the PSVT rate and the age of the patient (r=-0.500, p=0.00011). A negative correlation was also observed between the ST-segment score and the age of the patient (r=-0.429, p=0.0012). In 13 of 16 patients, coronary angiography did not reveal any significant 75% in area) stenosis. Exercise testing induced significant ST-segment depression in 3 patients, of whom two had significant coronary artery lesions. PSVT was due to atrioventricular reentry via an overt (n=3) or concealed accessory pathway (n=15), atrioventricular nodal reentry (n=5) and sinus node reentry (n=1). In conclusion, patients with a faster PSVT rate revealed more pronounced ST-segment depression than did those with a slower PSVT rate, possibly reflecting the modified repolarization process instead of coronary artery involvement. (Jpn Heart J 34: 269-278, 1993.)

Sympathetic stimulation of the Müller muscle may be responsible for most of the medically reversible cases of eyelid retraction in patients with Graves disease. The authors studied 21 patients with class I Graves ophthalmopathy (GO), 32 patients with Graves disease without ophthalmopathy (GD), and 12 control subjects. T1-weighted spin-echo magnetic resonance (MR) imaging was performed with a 0.5-T superconducting system. The thickness of the levator palpebrae superioris muscle was determined from sagittal MR images. The thickness of the levator muscles in patients with GD did not differ from the thickness in control subjects, but the levator muscles in patients with GO were significantly thickened (P < .01). The thickness of the levator muscles in patients with GO was significantly greater than in those of patients with GD (P < .01). In 64 orbits of patients with GD, 3% of levator muscles were thickened. In 33 of 40 (83%) orbits of patients with GO presenting with upper eyelid retraction, the levator muscles were thickened. Sagittal MR imaging demonstrated thickening of the levator muscles in patients with persistent upper eyelid retraction. The authors conclude that a thickened levator muscle probably causes upper eyelid retraction in patients with GO.

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