Computed Tomography Density Change in the Thyroid Gland Before and After Radiation Therapy.

BACKGROUND/AIM: Hypothyroidism is an established adverse effect of radiation therapy for head and neck cancer, and computed tomography (CT) density of the thyroid gland is lower in hypothyroid than euthyroid individuals. No previous studies have evaluated changes in CT densities of the thyroid gland caused by radiation therapy. The aim was to investigate the relationship between the change in CT density of the thyroid gland before and after radiation therapy for head and neck cancer and hypothyroidism. MATERIALS AND METHODS: This retrospective study analyzed data of 24 patients treated by radiation therapy for head and neck cancers. After dosimetric analysis of received radiation therapy, a Picture Archiving and Communication System was used to manually contour the thyroid on pre-treatment CT images to enable determination of mean thyroid gland CT densities and received radiation doses. Pre- and post-treatment thyroid function was assessed on the basis of serum TSH concentrations. Multivariate and univariate analyses were used to determine what clinical factors are associated with post-radiation therapy decrease in CT density of the thyroid and Pearson's χ2 test was used to assess correlations between these densities and TSH concentrations. RESULTS: Mean CT densities of the thyroid gland decreased from before to after radiation therapy in 73.9% of our patients (median decrease 16.8 HU). Serum TSH concentrations were significantly higher in patients with greater then median decreases in CT density than in those with lesser or no decreases. CONCLUSION: Post-radiation therapy hypothyroidism may be predicted by significant decreases in CT density of the thyroid gland.

The Mechanical Analysis of the Biofilm Streamer Nucleation and Geometry Characterization in Microfluidic Channels.

Bacteria can form biofilm streamers in microfluidic channels with various geometries. Experiments show that the streamer geometry, such as its shape or thickness, depends on the fluid velocity and the geometry and curvature of the microfluidic channel. In the paper, a mechanical analysis of the flow field is made in different channels, which shows that the secondary flow in the channel is the reason for streamer nucleation and that the shear stress distribution decides the streamer geometry including shape and thickness. Through a finite elements simulation, we obtain the secondary flow forming positions in both static and rotating channels: positions that are the location of nucleation of the streamer. Thick or wide biofilm streamers occur at the points of minimum shear stress in static channels. Furthermore, in rotating channels, spiral-like streamers form, due to the helical shape of the minimum shear stress distribution. The findings may allow the prevention of biofilm formation and also the removal of bacteria adhered onto certain surfaces in channels with small cross sections. The analysis also indicates how one can obtain desirable biofilm streamers by control of the channel geometry and the loading conditions.

Coronary angioscopic findings eight months after sirolimus-eluting stent implantation: a comparison between ST-elevation myocardial infarction and stable angina pectoris.

AIMS: Conflicting data exist about the safety of the sirolimus-eluting stent (SES) for patients with ST-elevation myocardial infarction (STEMI). Previous studies have reported delayed neointimal proliferation over SES with high incidence of adhering thrombus. This study was undertaken to assess the neointimal coverage and thrombus formation after SES implantation between patients with STEMI and those with stable angina pectoris (SAP). METHODS AND RESULTS: We studied 23 patients with STEMI who underwent primary percutaneous coronary intervention (PCI) with SES and 18 patients with SAP who were treated with SES. Coronary angioscopic examination was performed 8.1+/-2.4 months after PCI. Neointimal coverage of the stent was classified into four grades (grade 0 to 3). Uncovered stent strut was defined as grade 0 or 1. All the patients with STEMI and 94% of patients with SAP had uncovered stent struts. There was no significant difference in minimum, maximum, and dominant neointimal coverage grade between STEMI and SAP. 96% of patients with STEMI and all the patients with SAP showed heterogeneous neointimal coverage. Thrombus adhering to uncovered stent struts was observed in eight patients after STEMI and in four patients after SAP (35% vs. 22%, p=0.38). There was no significant difference in the maximum colour grade of the plaques between STEMI and SAP (2.1+/-0.8 vs. 1.8+/-0.9, p=0.33). Most thrombus was observed at the site of yellow plaques (83%). CONCLUSIONS: There was no significant difference in the neointimal coverage and thrombus formation between STEMI and SAP.

Effect of prodromal angina pectoris on the infarct progression in patients with first ST-elevation acute myocardial infarction.

BACKGROUND: Prodromal angina pectoris (AP) has a cardioprotective effect by the mechanism of ischemic preconditioning, and the QRS score on the admission electrocardiogram (ECG) reflects myocardial damage at presentation. This study was undertaken to investigate the effect of prodromal AP on infarct progression after the onset of acute myocardial infarction (AMI). METHODS AND RESULTS: The study group comprised 291 patients with a first ST-elevation AMI who underwent coronary angiography within 24 h of symptom onset. QRS score was calculated from the admission ECG. Patients were divided into 3 groups according to elapsed time from onset of AMI to angiography: early group (<2 h), intermediate group (2-6 h) and late group (6-24 h). Prodromal AP was defined as angina occurring 24 h before the onset of AMI. Patients with prodromal AP (n=101; 35%) had a significantly lower QRS score than those without (2.4+/-2.4 vs 3.2+/-3.0, P=0.02). In patients without prodromal AP, the QRS score linearly increased as elapsed time increased: 2.6+/-2.8, 3.0+/-3.0 and 5.5+/-2.9 in the early, intermediate and late groups, respectively. In patients with prodromal AP, the QRS score remained low until 6 h after onset and then increased: 2.0+/-1.8, 2.0+/-2.1, and 4.1+/-3.3, respectively. CONCLUSIONS: The findings suggested that prodromal AP might delay infarct progression during the early hours after the onset of AMI and extend the window of time for reperfusion therapy.

Accidental connection between the atrial and ventricular stylets during a stimulation threshold test for pacemaker implantation.

This report describes a case of atrioventricular crosstalk during a stimulation threshold test. This phenomenon was likely due to the accidental connection between the atrial and ventricular stylets. Electrocardiologists should recognize atrioventricular crosstalk during a stimulation threshold test to avoid repositioning the atrial lead unnecessarily or inducing ventricular arrhythmia.

Therapeutic hypothermia in combination with percutaneous coronary intervention in out-of-hospital cardiac arrest due to left main coronary artery disease.

A 59-year-old man had a witnessed collapse while driving a car. Approximately 10 min after the call to emergency services, paramedics arrived and initiated cardiopulmonary resuscitation. The first electrocardiogram (ECG) obtained by paramedics showed pulseless electrical activity. Review of his prehospital records documented that he experienced approximately 13 min of no flow or low flow before return of spontaneous circulation. On admission, he was still comatose with midrange dilated pupils. Electrocardiogram showed sinus rhythm, ST segment elevation in lead aVR, and ST segment depression in leads I, II, and V4-6. Coronary angiography showed 99% narrowing of the left main coronary artery (LMCA), but did not show any disease in the right coronary artery. A bare-metal stent was placed in the LMCA, and postdilated at 20 atmospheres. Immediately after return to the coronary care unit, therapeutic hypothermia was initiated. Hypothermia with a target temperature of 33.0 degrees C was maintained for 30 h. During this period, no significant hemodynamic instability occurred under intra-aortic balloon pumping (IABP) and intravenous catecholamines. Subsequently, he was slowly rewarmed at a rate of 0.3 degrees C/h up to 36.0 degrees C. Next day, the neurological condition improved and IABP was stopped. Creatine kinase increased to 2182 IU/l. Stent thrombosis did not occur despite the ad hoc loading of antiplatelet drugs. Follow-up echocardiography 9 days later showed mild hypokinesia of the anterior wall with an ejection fraction of 77%. He was discharged with no neurologic complications 18 days later.

History of diabetes mellitus as a neurologic predictor in comatose survivors of cardiac arrest of cardiac origin treated with mild hypothermia.

AIM: To investigate the impact of a history of diabetes mellitus on the neurologic outcome in comatose survivors of cardiac arrest of cardiac origin treated with mild hypothermia. METHODS: A prospective observational study was performed between September 2003 and July 2008. Eighty comatose survivors of cardiac arrest of cardiac origin were treated with mild hypothermia. Neurologic outcome at the time of hospital discharge, 30-day survival, and complications were assessed. RESULTS: Twenty-four of the 80 patients (30%) had a history of diabetes. The rate of favorable neurologic outcome was significantly lower in diabetic (17%) than in nondiabetic patients (46%) (p=0.01). The rate of 30-day survival was lower in diabetic (33%) than in nondiabetic patients (54%), but the difference was not significant (p=0.10). Multivariate analysis suggested that a history of diabetes was an independent predictor of unfavorable neurologic outcome (odds ratio 7.00, 95% confidence interval 1.42-46.19, p=0.03), but not for 30-day survival. There was no significant difference in the prevalence of complications. CONCLUSION: A history of diabetes is associated with poor neurologic outcome in comatose survivors of cardiac arrest treated with mild hypothermia.

The decrease in QRS amplitude after aortic valve replacement in patients with aortic valve stenosis.

PURPOSE: The purpose of this study was to evaluate the effect of aortic valve replacement on electrocardiogram (ECG) in patients with aortic valve stenosis. METHODS: Serial 12-lead ECGs were obtained in 15 patients with aortic valve stenosis who underwent aortic valve replacement. Three ECG indexes for left ventricular hypertrophy were manually measured in each ECG: Sokolow-Lyon index (sum of S wave in V(1) and R wave in V(5)), Cornell voltage index (sum of R wave in aVL and S wave in V(3)), and Gubner index (sum of R wave in I and S wave in III). RESULTS: After aortic valve replacement, Sokolow-Lyon index gradually decreased during 2 years (51.1 +/- 17.9 to 34.8 +/- 12.5 mm, P < .01). Cornell voltage index (25.6 +/- 7.0 to 15.0 +/- 4.8 mm, P < .01) and Gubner index (15.8 +/- 7.6 to 10.3 +/- 5.5 mm, P < .01) also gradually decreased during 2 years. ST depression in V(6) was found in 14 patients (93%) before aortic valve replacement. It resolved in 9 of 14 patients during 2 years. CONCLUSIONS: Electrocardiographic evidence of left ventricular hypertrophy gradually resolved after aortic valve replacement in patients with aortic valve stenosis.

Prevalence of incidental coronary artery disease in tako-tsubo cardiomyopathy.

OBJECTIVE: Earlier studies have often required the absence of obstructive coronary artery disease (CAD) as the criteria. However, it is probable that patients with tako-tsubo cardiomyopathy have an incidental CAD because most patients are elderly. We assessed the prevalence of incidental CAD. METHODS: We reviewed coronary angiograms of 97 Japanese patients with tako-tsubo cardiomyopathy. A wrapped left anterior descending artery (LAD) was defined as a LAD that perfused at least one-quarter of the inferior wall of the left ventricle in the 30 degrees right anterior oblique projection. RESULTS: Ten patients (10%) had definitively incidental CAD defined as greater than 75% reduction in the luminal diameter of the major epicardial coronary artery. All patients had ST-segment elevation, and five patients had T-wave inversion on admission. Nine patients had single vessel disease, and one patient had double vessel disease. Six patients had CAD in the nonwrapped LAD, and they were judged to be definitively incidental. Three patients had CAD in the left circumflex artery, and two patients had CAD in the right coronary artery. CONCLUSION: This study showed that incidental CAD was found in 10% of Japanese patients with tako-tsubo cardiomyopathy. In patients with CAD in the LAD, it should be carefully judged whether the CAD causes left ventricular apical ballooning to avoid performing coronary revascularization unnecessarily.

Assessment of medications in patients with tako-tsubo cardiomyopathy.

BACKGROUND: Tako-tsubo cardiomyopathy has been gradually recognized worldwide. However, medications for the prevention remain not to be investigated in part because the precise mechanism is unclear. We sought to examine medications before the onset of tako-tsubo cardiomyopathy, and to prove the limitation of these medications for the prevention. METHODS AND RESULTS: This study consisted of 21 patients with tako-tsubo cardiomyopathy who received one or more medications for hypertension or suspected angina pectoris. Each patient was assessed with history, medications, coronary angiography and left ventriculography. All patients but 1 were female, and age ranged 41 to 87 years (73+/-11 years). Twelve patients received calcium channel blockers, 7 patients received nitrates, and one patient received beta blocker. Three patients received angiotensin coverting enzyme inhibitors, and 4 patients received angiotensin II receptor blockers. One patient died of serious pneumonia, but there was no patient who died of tako-tsubo cardiomyopathy itself. During the 3 year follow-up, one patient receiving angiotensin receptor blocker had the recurrence of tako-tsubo cardiomyopathy due to recurrent epileptic seizure. CONCLUSIONS: Tako-tsubo cardiomyopathy can occur despite treatment with calcium channel blockers, nitrates or beta-blockers, suggesting limitation of these medications to prevent tako-tsubo cardiomyopathy.

Electrocardiographic prediction of short-term prognosis in patients with acute myocardial infarction associated with the left main coronary artery.

PURPOSE: The purpose of this study was to assess the usefulness of electrocardiogram on admission to predict short-term prognosis in patients with acute myocardial infarction (AMI) associated with left main coronary artery (LMCA). METHODS: Electrocardiogram was obtained on admission in 41 patients with AMI associated with LMCA who underwent reperfusion therapy. Electrocardiographic findings were compared between nonsurvivors and survivors. RESULTS: There were 24 nonsurvivors and 17 survivors during 30-day follow-up. Nonsurvivors had ST-segment elevation in both leads aVR and aVL (54% vs 18%, P < .05), left anterior fascicular block (83% vs 41%, P < .05), and right bundle-branch block (54% vs 18%, P < .05) more frequently, and ST-segment depression in lead V(5) (17% vs 59%, P < .05) less frequently than survivors among patients with AMI associated with LMCA. CONCLUSIONS: Our data suggested that electrocardiogram on admission might be useful to predict short-term prognosis in patients with AMI associated with LMCA.

Trends in gender difference in mortality after acute myocardial infarction.

BACKGROUND: Progress in management of acute myocardial infarction (AMI) might have changed the effect of gender on mortality. METHODS: From May 1981 to November 2002, 1984 consecutive patients with AMI underwent emergency coronary angiography. They were divided into three groups in chronological order: group I (1981-1988, n=564); group II (1989-1995, n=678); and group III (1997-2002, n=742). Multi-variable analysis was performed using Cox's proportional hazard regression, adjusting baseline clinical and angiographical variables. RESULTS: There were 405 women (20%). Thrombolysis was most frequently performed in group I (50%), balloon angioplasty in group II (71%), and stent in group III (66%), with no difference in the allocation of reperfusion therapy between men and women. Three-year mortality was significantly higher in women than in men in group I (27% vs 18%, p=0.03) and group II (23% vs 15%, p=0.048). In group III, there was no significant difference in 3-year mortality (12% vs 10%, p=0.66) between women and men. Women were associated with higher age, more diabetes, more hypertension, fewer current smokers, and less previous infarction than men. Multi-variable analysis showed that sex was not an independent predictor of 3-year mortality in the three groups. CONCLUSIONS: Women with AMI who were treated mostly with primary intervention using stent in the contemporary era had similar mortality to men.

Therapeutic hypothermia after out-of-hospital cardiac arrest due to Brugada syndrome.

A 56-year-old man was admitted to our hospital after successful resuscitation for out-of-hospital cardiac arrest. Electrocardiogram on admission showed right bundle branch block and ST segment elevation in leads V1-3. Subsequent intravenous infusion of isoproterenol rapidly resolved ST segment elevation, suggesting Brugada syndrome. Therapeutic hypothermia, that was performed with a target temperature of 34.0 degrees C did not induce ST segment elevation in leads V1-3. The J-ST segment elevation rather became much more normal, suggesting a beneficial effect of mild therapeutic hypothermia. Serial ECG showed the temporal variation of ST segment elevation, and pilsicainide challenge test showed the occurrence of ST segment elevation, confirming the diagnosis of Brugada syndrome. Clinical observation suggested that mild therapeutic hypothermia reversed the Brugada phenotype through the prevention of fever as well as being indicated for cerebral protection after cardiac arrest. In conclusion, therapeutic hypothermia with a temperature of 34.0 degrees C can be used safely in Brugada syndrome.

[Right ventricular perforation by screw-in lead after permanent pacemaker implantation: a case report].

A 93-year-old man received a permanent implanted pacemaker(VVI mode) to treat completed atrioventricular block in our hospital. However, pacing failure appeared 4 days later. Computed tomography showed right ventricular perforation by the screw-in lead. There was no evidence of cardiac tamponade or symptoms, so we inserted another lead into the right ventricular outflow tract without removing the first lead. This patient still has the pacing lead that perforated the right ventricle, so careful observation will be needed even after discharge.

[Influence of deficit in top-of-the-head CT images on STI dose calculation].

In 54 cases of stereotactic irradiation (STI) seen at our hospital from April 2000 to March 2001, we examined the deficit in top-of-the-head computed tomography (CT) images and the influence that this deficit had on calculation of the STI dose. Results showed a slice deficit of more than 5 mm in 16 of the 54 cases and a maximum deficit of 25 mm. In most cases, the Gill-Thomas-Cosman (GTC) frame was used. The error in total dose monitor unit (DMU) calculation can be ignored if the top-of-the-head CT image deficit is less than 10 mm. If the deficit is more than 20 mm, it is possible that the total DMU calculation error will exceed 2 . In cases in which the deficit was greater than 30 mm, the average calculation error was 2.00 , and, in one case, the error was more than 7 . The GTC frame tends to produce CT image deficits in top-of-the-head images, whereas such images do not suffer this loss when a Brown-Roberts-Wells (BRW) head ring is used. When the CT image deficit is large, it is necessary to reduce the ratio of the arc that passes the area of the CT image deficit and to decrease the dose weight of the arc.