The effects of glucose and insulin on J-ST-segment elevation were evaluated in seven men (mean age 45 +/- 10 years) with Brugada syndrome. Six patients had been reanimated from VF and one patient had experienced syncope. The effects of intavenous (1) pilsicainide 50 mg, (2) glucose 50 g, and (3) glucose 50 g plus regular insulin 10 IU on the precordial ECG leads were examined. Pilsicainide significantly enhanced J-ST elevation in all patients and induced VF in 1 patient. A significant accentuation of the abnormal J-ST configuration was observed in all patients at a mean of 51 +/- 40 minutes after glucose and insulin infusion. Changes in blood glucose and serum potassium concentration were 111 +/- 158 mg/dL and -0.30 +/- 0.48 mEq/L, respectively. These changes were not directly related to the ECG changes. Glucose infusion without insulin caused a subtle increase in J-ST elevation. In conclusion, the administration of glucose and insulin safely unmasked or accentuation the J-ST-segment elevation in Brugada syndrome. Blood glucose and insulin concentrations may be factors modulating the circadian or day-to-day ECG variations in this syndrome.

SUMMARYMyocardial stunning with hyperthyroidism is rare. A 79-year old woman with hyperthyroidism was admitted to our hospital complaining of palpitations due to paroxysmal atrial fibrillation. An echocardiogram showed akinesis of the apical wall which was not observed 2 weeks before admission. Cardiac catheterization performed in the acute phase showed normal coronary arteries and no evidence of provocative spasms. The wall motion abnormality disappeared entirely after 1 week in hospital. We report a case of transient left ventricular dysfunction, so called "takotsubo" cardiomyopathy, associated with hyperthyroidism. (Jpn Heart J 2004; 45: 889-894)

atent foramen ovale (PFO) and atrial septal aneurysm (ASA) have been identified as potential risk factors for stroke; 1-5 when transesophageal echocardiography (TEE) is used, the prevalence of PFO in the normal population is as high as 22-38%. 6 However, it is often difficult to prove that the mechanism of systemic embolism was paradoxical embolism in stroke patients with PFO. 1 We present a case of impending paradoxical cerebral embolism diagnosed by TEE and contrast echocardiography. Case ReportAn 89-year-old man was admitted to the Hokushin General Hospital with hemiparesis of the left limbs and impaired consciousness. On physical examination, he had normal heart sounds, left hemiparesis, and no swelling of the lower limbs. Computed tomography (CT) and magnetic resonance imaging (MRI) of the brain showed cerebral infarction in the area of the right middle cerebral artery (Fig 1). Magnetic resonance angiography (MRA) showed no atherosclerotic changes in the large cerebro-vascular walls. Electrocardiogram showed sinus rhythm and he had an episode of chronic atrial fibrillation before admission. The chest X-ray and laboratory data presented no abnormalities.Because there was no definite evidence of artery to artery stroke, we performed transthoracic echocardiography (TTE) to rule out a cardiac source of the emboli. TTE showed a slightly enlarged right ventricle, mild tricuspid regurgitation (max pressure gradient =34 mmHg), atrial septal aneurysm, and a floating mass in the left atrium (Fig 2A). To further examine that mass, we performed TEE, which showed a large string-like mass transiting from the right atrium (RA) to the left atrium (LA) through the atrial septum (Fig 2B), and the absence of any thrombus on the left atrial appendage (Fig 2C).We diagnosed paradoxical cerebral embolism caused by intra-atrial thrombus. Peripheral Doppler echocardiography of the lower extremities revealed normal flow velocities and no existence of deep vein thrombosis. A hypercoagulability profile for intravascular blood stasis was also negative.We chose anticoagulation therapy rather than surgical embolectomy because of the patient's age and poor general condition. After 4 weeks of warfarin therapy, the atrial mass had completely disappeared from the TEE images. Right-to-left shunt flow was not identified with color flow Doppler, although it was proved with a contrast study under the provocative maneuver (Fig 3). We used a microbubble contrast agent (Levovist R , Shering Co Ltd) instead of hand-agitated saline to avoid possible systemic air Circ J 2005; 69: 246 -248 (Received September 10, 2003; revised manuscript received January 19, 2004; accepted February 18, 2004) Departments of Cardiology and *Neurology, Hokushin General Hospital, Nagano, Japan Mailing address: Toshihiko Takamoto, MD, FACC, Department of Cardiology, Hokushin General Hospital, 1-5-63 Nishi, Nakano, Nagano 383-8505, Japan. E-mail: ttakamoto-circ@umin.ac.jp Impending Paradoxical Cerebral Embolism in a PatientWith Atrial Septal Aneurysm

Serum thyrotropin (TSH) concentrations in normal young men were measured by a high-sensitivity immunoradiometric assay before and after intravenous administration of 500 micrograms of TSH-releasing hormone (TRH). A kinetic model was applied to evaluate the secretion rate both before (V0) and after (V0 + V* at maximum rate) the administration of TRH, the elimination constant (K), the latent time (L) between TRH administration and start of the stimulated secretion, and the total amount of TSH (T) released in response to TRH. V0, V* and T varied widely from individual to individual, but correlated well with TSH before TRH administration (r = 0.93, 0.80 and 0.87, respectively). A few minutes (1.89 +/- 1.30 min) after the administration of TRH, the secretion of TSH (0.025 +/- 0.016 microU/min ml) was stimulated, and the total release over about 1 h was 12.5 +/- 5.6 microU/ml. Serum TSH was maximum at 31.5 +/- 5.7 min. The half-time of disappearance of TSH was 42 +/- 9 min. These data confirm that the stimulated secretion continues for more than 30 min, and that the pituitary releases 43.2 +/- 22.9 mU of TSH (assuming the distribution volume of TSH is 5.8% of body weight) in response to TRH, an amount which correlates closely (r = 0.91) with TSH before TRH administration.