Bunji Kaku

Effects of Troglitazone on Frequency of Coronary Vasospastic-Induced Angina Pectoris in Patients With Diabetes Mellitus

This study investigates the effects of troglitazone, an insulin sensitizer, on the clinical manifestation of coronary vasospastic angina pectoris in patients with diabetes mellitus. Troglitazone reduces frequency of angina pectoris and improves endothelial function.

High Incidence of Sudden Cardiac Death With Conduction Disturbances and Atrial Cardiomyopathy Caused by a Nonsense Mutation in the STA Gene

Background—The STA gene encodes emerin and is one of the genes that is affected in Emery-Dreifuss muscular dystrophy (EDMD). Although it has been reported that EDMD caused by the STA gene mutation is associated with X-linked recessive inheritance, the genotype-phenotype correlations, with special reference to cardiac manifestations, are not well defined. Methods and Results—We identified 16 carriers (7 male and 9 female) with a nonsense mutation in exon 6 of the STA gene in 2 EDMD families. Pacemakers were required for treatment of bradyarrhythmias in all 7 male carriers and in 2 of the 9 female carriers. In addition, 2 of the 9 female carriers displayed atrial fibrillation. In these 2 families, 3 males without pacemaker implantation, who were not tested genetically, had died suddenly. In these family members, the majority of carriers with the mutation had not been clinically diagnosed as having EDMD before genetic testing because of extremely mild or nonexistent skeletal myopathy. Conclusions—EDMD caused by this mutation is characterized by atypical clinical features and incomplete penetrance of the clinical phenotype and may result in serious cardiac complications, including sudden death. Approaches to preventing possible sudden death in carriers with the STA gene mutation require further study.

Effects of short-term aminophylline administration on cardiac functional reserve in patients with syndrome X

OBJECTIVES This study sought to evaluate the effect of adenosine receptor blockade by aminophylline on cardiac functional reserve in patients with syndrome X. BACKGROUND Aminophylline may have a potentially antiischemic effect through the inhibition of adenosine and, thus, the coronary steal phenomenon in patients with syndrome X. METHODS A single-blind, placebo-controlled study of an intravenous infusion of aminophylline (6 mg/kg body weight over 15 min) or placebo (20 ml of saline solution over 15 min) was performed during continuous radionuclide monitoring of left ventricular ejection fraction in 12 patients performing supine bicycle ergometric exercise. RESULTS Aminophylline increased exercise time (aminophylline 400 s vs. placebo 355 s, p < 0.01), decreased degree of ST segment depression (aminophylline 1.6 mm vs. placebo 2.4 mm, p < 0.01) and either abolished (seven patients) or diminished (five patients) chest pain during exercise. Aminophylline also increased left ventricular ejection fraction at rest (aminophylline 66.5% vs. placebo 62.3%, p < 0.05) but did not improve its deterioration at peak exercise (aminophylline 60.1% vs. placebo 56.6%, p = NS) or shorten the abnormally prolonged interval between the end of exercise and the overshoot (aminophylline 115 s vs. placebo 130 s, p = NS). CONCLUSIONS Aminophylline infusion increases ischemic threshold and prolongs exercise duration in patients with syndrome X. It is hypothesized that aminophylline acts by inhibiting the coronary steal phenomenon through adenosine receptor blockade. It does not improve the deterioration in left ventricular function at peak exercise or the delayed response in ejection fraction in the recovery period, presumably because the beneficial effects of aminophylline that result from the redistribution of coronary blood flow are limited.

Abnormal sympathetic innervation of the heart in a patient with Emery-Dreifuss muscular dystrophy

A 33-year-old man was admitted for general malaise and vomiting. An electrocardiogram showed a complete atrioventricular block and an echocardiogram showed right atrial dilatation and normal wall motion of left ventricle (LV). Gene analysis showed nonsense mutation in the STA gene, which codes for emerin, and Emery-Dreifuss muscular dystrophy was diagnosed. An endomyocardial biopsy of right ventricle showed mild hypertrophy of myocytes. Myocardial scintigraphic studies with Tc-99m methoxyisobutylisonitrile (MIBI) and I-123-betamethyl-p-iodophenylpentadecanoic acid (BMIPP) scintigrams showed no abnormalities. In contrast, I-123 metaiodobenzylguanidine (MIBG) scintigrams showed a diffuse and severe decrease in accumulation of MIBG in the heart. Six months later, his LV wall motion on echocardiograms developed diffuse hypokinesis. These results suggest that the abnormality on I-123 MIBG myocardial scintigrams may predict LV dysfunction in Emery-Dreifuss muscular dystrophy.

Life-threatening ventricular arrhythmia due to silent coronary artery spasm: usefulness of I-123 metaiodobenzylguanidine scintigraphy for detecting coronary artery spasm in the era of automated external defibrillators: a case report.

IntroductionCardiac arrhythmia is sometimes life-threatening, and automated external defibrillators are presently used in some countries. Coronary artery spasm is one of the primary causes of life-threatening arrhythmia. In general, chest symptoms are key indicators of possible coronary artery spasm; however, if chest symptoms are not present, clinicians may not suspect this disease. We encountered a patient who had recovered from ventricular fibrillation treated by using an automated external defibrillator, and silent coronary artery spasm was considered to be the cause of this life-threatening arrhythmia. In this case, I-123 metaiodobenzylguanidine scintigraphy was a useful screening tool for a silent coronary artery spasm.Case presentationA 72-year-old Japanese man was transferred to our hospital after recovering from ventricular fibrillation treated by using an automated external defibrillator. He had never complained of chest symptoms previously. Decreased uptake of I-123 metaiodobenzylguanidine was observed in the inferolateral and anteroseptal walls of the left ventricle. A spasm provocation test of the coronary artery was performed, and silent coronary artery spasm was diagnosed as the underlying disease.ConclusionNon-invasive I-123 metaiodobenzylguanidine scintigraphy was a useful screening tool for silent coronary artery spasm as a possible cause of cardiopulmonary arrest in a patient with no chest symptoms.

Localized Right Subclavian Artery Dissection Detected by Accident on an Ultrasound Examination: A Case Report and Literature Review

Right subclavian artery dissection was detected in a 78-year-old female victim of the Kumamoto earthquake during a carotid artery ultrasound examination. She was subsequently taken to hospital and diagnosed with localized subclavian artery dissection (LSAD) by contrast-enhanced computed tomography. There have been no previous reports of LSAD detected at a medical checkup. LSAD may progress and become severe, even in asymptomatic patients or patients with mild symptoms, and careful long-term follow-up is therefore required in all patients diagnosed with LSAD.

Hereditary Hemorrhagic Telangiectasia with SMAD4 Mutations is Associated with Fatty Degeneration of the Left Ventricle, Coronary Artery Aneurysm, and Abdominal Aortic Aneurysm

A 52-year-old man with recurrent epistaxis and palpebral conjunctival telangiectasia visited our hospital for a follow-up checkup for gastrointestinal polyposis. At 48 years of age, he underwent Y-graft replacement for an abdominal aortic aneurysm. Arteriovenous malformation was detected in his lungs, and a genetic test revealed an SMAD4 mutation. Eventually, he was diagnosed with juvenile polyposis-hereditary hemorrhagic telangiectasia (JP-HHT) syndrome. In addition, fatty degeneration of the left ventricle and a coronary aneurysm were detected. This is the first report suggesting the possibility of an association between these manifestations and JP-HHT due to SMAD4 mutations. Examining cardiovascular disorders in JP-HHT patients is imperative.

Ultrasound Vasography Evaluation of Radial Arterial Grafts used for Coronary Arterial Bypass Surgery

OBJECTIVES For coronary bypass surgery, radial arteries are often used as bypass grafts. Some of these arteries however, have arteriosclerotic lesions. We attempted to evaluate the relationship between arteriosclerosis and vasodilation. METHODS Prior to bypass surgery, 20 patients underwent ultrasound vasography to determine the condition of their radial and brachial arteries. Flow-mediated dilation, which is the same as endothelium-dependent vasodilation, was measured in the brachial artery of the nondominant arm by reactive hyperemia after 5-minute forearm ischemia. Vasodilation after application of a sublingual glyceryl trinitrate spray was also measured. RESULTS During surgery, 4 of 20 radial arteries demonstrated calcification, and 3 of the 4 could be used by removing the calcified part. However, the other artery, which had extensive calcification that could not be detected by ultrasound vasography, was discarded. The amount of vasodilation seen after the administration of sublingual glyceryl trinitrate had no correlation with calcified grafts. Calcified radial arteries demonstrated significantly poor brachial artery vasodilation by an endothelial-dependent vasodilation test. CONCLUSIONS Calcification in radial arteries can thus only be evaluated by flow-mediated dilation.