Discrimination between His-bundle and the Right Bundle Branch during Electrophysiologic Studies

Background: The purpose of this study was to identify the His-bundle (HB) versus right bundle branch (RBB) during electrophysiologic studies, using the V3 phenomenon, and to compare the timing of HB versus RBB potentials of sinus cycles (His-ventricular [H-V] interval).
Methods: The study enrolled 16 patients without structural heart disease, who underwent electrophysiologic studies during which the H-V interval was within normal limits and the V3 phenomenon was induced during recordings of the HB and the RBB potentials by a multi-electrode catheter. The recording site of the earliest HB potential just before the V3 phenomenon was defined as the branching portion of His bundle (HBBP), the site immediately proximal to the HBBP as the HB, and the site immediately distal to the HBBP as the RBB.
Results: The HBBP was identified in all patients. In all cases but one patient, the H-V interval measured at the HB adjacent to the HBBP was ≥35 ms. However, in 12 patients, the H-V interval measured at the RBB adjacent to the HBBP was also ≥35 ms.
Conclusions: The electrophysiologic identification of HB versus RBB by simultaneous recordings of HB and RBB potentials during induction of the V3 phenomenon was feasible. When the discrimination between HB and RBB was based on the measurement of the H-V interval, the proximal portion of the RBB was frequently misidentified as the HB.     

CB1 Cannabinoid Receptor-Dependent and -Independent Inhibition of Depolarization-Induced Calcium Influx in Oiigodendrocytes

Ca2+稳态平衡的调节在少突胶质细胞功能和存活中起重要作用.大麻素CB1和CB2受体在许多细胞中调节Ca2+水平和/或K+电流.本文利用培养的少突胶质细胞中,通过增高细胞外K+浓度(50 mM诱导膜去极化,研究大麻素复合物在此过程引发钙内流中的作用.CB2受体激动剂ACEA导致去极化诱导的少突胶质细胞胞浆的Ca2+瞬变表达浓度依赖性抑制,最大效应为(94±3)%,半效应浓度(EC50)为(1.3±0.03)μM.这种作用可被CB2/CB2激动剂CP55、940、内源性大麻素类AEA和2-AG所模拟,但是CB2受体选择性激动剂JWH133没有作用.CB2受体拮抗剂AM251(1μM)也可减少细胞外高K+诱导的Ca2+反应.但不能防止ACEA(3 μM)诱发的抑制效应.然而,ACEA和AEA减少去极化诱导的Ca2+瞬变的能力在CB2受体敲除小鼠和经百日咳毒素预处理的少突胶质细胞中明显降低.内流性K2+通道阻断剂BaCI:(300 μM)和CsCl2(1 mM)降低电压诱导的Ca2+内流并部分阻断ACEA的抑制效应.本文表明,大麻素抑制少突胶质细胞中去极化诱导的Ca2+瞬变是通过包括PTX-敏感的Gi/o蛋白和阻断K2+内流通道的CB2受体依赖性和非依赖性机制.     

Assessment of body composition measured by bioelectrical impedance in children

Bioelectorical impedance methods have been found to be a valid and reliable way of estimating per cent body fat (%BF) in adults. We applied them to healthy children and compared them with conventional anthropometry methods. One thousand two hundred and sixteen children participated in this study. Impedance and skinfold thickness were measured, and %BF was estimated using these values. Bodyweight and height were measured, and per cent obesity (%OB) and body mass index (BMI) were obtained. The values of %BF by the bioelectrical impedance method (%BFi) were 8.6 ± 4.0% in the junior male group, 14.2±2.8% in the junior female group, 7.9±4.7% in the senior male group and 16.1 ±2.9% in the senior female group. The % BFi correlated strongly with skinfold thickness, %OB and BMI. Thus %BFi correlated strongly with variables from conventional methods. It was concluded that it is a reliable way of assessing lipid storage in children.     

Serum N-acetylglucosaminyltransferase III activities in hepatocellular carcinoma

N-Acetylglucosaminyltransferase III (GnT III) catalyses the addition of N-acetylglucosamine through a β 1–4 linkage to the mannose of the trimannosyl core, resulting in conversion of the concanavalin A (Con A)-reactive glycan into a non-reactive state. In this study, we measured GnT III activity to evaluate its diagnostic efficacy and its therapeutic effect on hepatocellular carcinoma (HCC). Concanavalin A-non-reactive fraction of serum transferrin (Tf) was also determined since the sugar chains of Tf are one of the possible candidates for the product of GnT III. Serum samples (159) were used from patients with HCC (89), liver cirrhosis (30), chronic hepatitis (19), alpha-fetoprotein (AFP) producing gastric carcinoma metastatic to the liver (five) and healthy controls (16). N-Acetyl-glucosaminyltransferase III activity was determined by high performance liquid chromatography. The reactivity of serum Tf to Con A was also analysed in 21 paired HCC samples before and after treatment by crossed immuno-affinoelectrophoresis. N-Acetylglucosaminyltransferase III activity from the HCC group (153 ± 72 pmol/mL/h) was significantly higher than that from liver cirrhosis (99 ± 67 pmol/mL per h), chronic hepatitis (84 ± 39pmol/mL per h) and the normal controls (62 ± 16pmol/mL per h). N-Acetylgiucosaminyltransferase III activity of 21 patients with HCC was significantly reduced after treatment such as transcatheter arterial chemoembolization and/or percutaneous ethanol infection therapy, (123 ± 77 to 100 ± 60pmol/mL per h). Commensurate decreases of AFP and des-γ-carboxy prothrombin with GnT III activity were also observed after treatment. The Con A-non-reactive fraction (n= 21; 6.4 ± 2.3%) in patients with HCC after treatment was significantly lower than before (8.2 ± 2.4%). The present study suggests that GnT III activity is a possible and in the diagnosis and evaluation of HCC, especially when other tumour markers are negative.     

Time- Versus Frequency-Domain Analysis in Predicting Cycle Length of Inducible Ventricular Tachycardia After Myocardial Infarction

To determine whether time- and frequency-domain analyses differ in their ability to predict sustained ventricular tachycardia (VT) induced by programmed ventricular stimulation, 60 consecutive patients with myocardial infarction and 30 healthy control subjects were evaluated. Programmed ventricular stimulation using three extrastimuli and signal-averaged ECG recordings were performed in patients with myocardial infarction. Of the 60 patients, sustained monomorphic VT (SMVT) with cycle length (CL) ± 250 ms (slow SMVT) was inducible in 9, and SMVT with CL < 250 ms (fast SMVT) was inducible in 9. The durations of the filtered QRS (f-QRS) at each high-pass filter (25, 40, and 80 Hz) and the low amplitude signal (LAS) at 25-Hz high-pass filtering were significantly longer in the slow SMVT group than in the fast SMVT, no VT, or normal control group. The root-mean- square voltages at 25-Hz and 8Q-Hz high-pass filters in the slow SMVT group were significantly lower than in the fast SMVT, no VT, or normal control group. There was no significant difference in time- domain variables among fast SMVT, no VT, and normal control groups. The CL of the induced sustained VT was significantly correlated with the durations of f-QRS and LAS, Concerning frequency-domain variables (area ratio and factor of normality), there was no significant difference between slow and fast SMVT groups. Both the slow and fast SMVT groups had a significantly higher area ratio and a significantly lower factor of normality than the group with no VT or the normal control subjects. In conclusion, there were significant correlations between time-domain variables and CL of SMVT, while there was no correlation when using frequency-domain parameters.     

Humidification during high-frequency oscillation ventilation is affected by ventilator circuit and ventilatory setting

Background:  High-frequency oscillation ventilation (HFOV) is an accepted ventilatory mode for acute respiratory failure in neonates. As conventional mechanical ventilation, inspiratory gas humidification is essential. However, humidification during HFOV has not been clarified. In this bench study, we evaluated humidification during HFOV in the open circumstance of ICU. Our hypothesis is that humidification during HFOV is affected by circuit design and ventilatory settings.
Methods/Materials:  We connected a ventilator with HFOV mode to a neonatal lung model that was placed in an infant incubator set at 37°C. We set a heated humidifier (Fisher & Paykel) to obtain 37°C at the chamber outlet and 40°C at the distal temperature probe. We measured absolute humidity and temperature at the Y-piece using a rapid-response hygrometer. We evaluated two types of ventilator circuit: a circuit with inner heating wire and another with embedded heating element. In addition, we evaluated three lengths of the inspiratory limb, three stroke volumes, three frequencies, and three mean airway pressures.
Results:  The circuit with embedded heating element provided significantly higher absolute humidity and temperature than one with inner heating wire. As an extended tube lacking a heating wire was shorter, absolute humidity and temperature became higher. In the circuit with inner heating wire, absolute humidity and temperature increased as stroke volume increased.
Conclusion:  Humidification during HFOV is affected by circuit design and ventilatory settings.     

Coronary risk factors in school children in relation to their family history of coronary heart disease and hyperlipidemia

A school-based study was implemented to assess the family history of coronary heart disease (CHD) and hyperlipidemia (HL) in relation to serum lipoprotein and apolipoprotein levels. One hundred and twenty-five elementary school students (aged9–10 years) and 297 junior high school students (aged12–13 years) participated. Family history was evaluated by the following scoring method: positive family history in a parent. 2 points: in a grandparent. 1 point: and onset of CHD before age 60, 1 additional point. Family history of HL was positive in 8.2% of elementary school students, and 4.2% in junior high school students. Family history of CHD was positive in 11.5% of elementary students, and 11.0% in junior students. Family history score (FHS) for HL was related to serum total cholesterol (TC), low density lipoprotein cholesterol (LDLC), high density lipoprotein cholesterol, apolipoprotein A-T, apolipoprotein B (apoB) and lipoprotein (a) in elementary students, and to TC, LDLC, triglyceride and apoB in junior students. There was no relationship between FHS for CHD and serum lipoprotein or apolipoprotein levels in any student. The children with a positive FH of HL already demonstrated an atherogenic lipid profile while those with FH of CHD did not. which was probably because lipid profiles in children are more genetically mediated by a FH of HL than of CHD.     

Liver transplantation in a case of hypoproteinemia and coagulopathy

A female infant with hypoproteinemia and coagulopathy associated with hypertyrosinemia was successfully treated with living-related liver transplantation (LRLT). On the 12th day of life plasma amino acid analysis revealed a marked elevation of tyrosine, so the patient was fed on a low-tyrosine and low-phenylalanine diet. However, hepatosplenomegaly. hypotonia, alopecia, eczema and psychomotor delay did not improve and recurrent episodes of disseminated intravascular coagulation (DIC) caused her condition to deteriorate. Liver biopsy on the 230th day revealed marked fatty change accompanied by mild to moderate cholestasis. Therefore. LRLT from her father was performed on the 286th day resulting in improvement of all the aforementioned signs and symptoms. Despite a thorough examination, no diagnosis of a known disorder could be established. However, her elder brother had also been born with severe hypoproteinemia and coagulopathy, and died of DIC on the second day of life. Thus, the disorder is designated as a new entity, namely ‘congenital hypoproteinemia and coagulopathy associated with hypertyrosinemia’.     

Long-Term Results of Cryoablation with a New Cryoprobe to Eliminate Chronic Atrial Fibrillation Associated with Mitral Valve Disease

The purpose of this study was to examine the performance of a new cryoprobe in the treatment of chronic atrial fibrillation (AF) associated with mitral valve disease. The study included 66 patients undergoing mitral valve replacement. The mean AF duration was 9.0 ± 9.0 years and mean left atrial (LA) was diameter 57 ± 10 mm. Cryoablation (−60°C) was applied to four pulmonary vein (PV) orifices over 2–3 minute. The spherical tip (2-cm in diameter) of the cryoprobe is capable of ablating the left atrium near the PV, as well as the PV ostium with a single cryoablation. After cryoablation, mitral valve surgery or a combined surgical procedure were performed in 66 patients. There were no intraoperative complications. Sinus rhythm was restored in 60 patients (91%) immediately after the operation. Recurrent AF was treated with antiarrhythmic drugs and/or direct current cardioversion in 43 patients (72%). At discharge, 48 patients (72%) were in sinus rhythm. During a mean follow-up period of 31 ± 16 months, 40 patients (61%) were in sinus rhythm with (29) or without antiarrhythmic drugs (11). In patients in sinus rhythm at the end of the follow-up period, the duration of preoperative AF duration was significantly shorter (P < 0.05) and the preoperative LA diameter and cardiothoracic ratio were significantly smaller than in patients who were in AF (both for P < 0.005). Using this new cryoprobe, sinus rhythm was restored and maintained in 61% of patients with chronic AF and mitral valve disease with a 12–15 minute cryoablation procedure.     

Conduction Delay in Right Ventricle as a Marker for Identifying High‐Risk Patients With Brugada Syndrome

Conduction Delay as a Marker for Brugada Syndrome. Objectives: To evaluate the significance of conduction delay (CD) in the right ventricle (RV) in Brugada syndrome (BS) as a marker for risk stratification of sudden death. Methods: Twenty‐five patients with BS (7 with documented ventricular fibrillation (VF), 8 with syncope, and 10 without symptoms) and 10 control subjects were paced from the RV apex using 8 beats of drive pacing and a single extra‐stimulus. CDs in the right ventricular outflow tract (RVOT) (CD‐RV) and in the lateral left ventricle (L‐LV) (CD‐LV), and the local electrogram durations at a single extra‐stimulus in RVOT (D‐RV) and L‐LV (D‐LV) were calculated. We also evaluated changes in 12‐lead ECG parameters in 16 patients with BS after pilsicainide challenge test (Pilsicainide‐test). Results: Maximal CD‐RV and maximal D‐RV were significantly larger than maximal CD‐LV and maximal D‐LV in BS (26 ± 10 and 105 ± 15 vs 20 ± 6 and 92 ± 15 ms, P < 0.05, respectively). Maximal CD‐RV and maximal D‐RV in patients with documented VF were the largest among the 3 groups. There was a significant positive correlation between maximal CD‐RV or maximal D‐RV and changes in QRS duration in leads V2 and V5 and in S wave duration in lead II and V5 after Pilsicainide‐test (CD‐RV; r = 0.54, 0.51, 0.56, and 0.53: D‐RV; r = 0.55, 0.5, 0.57, and 0.53, P < 0.05, respectively). In control subjects, there were no significant differences. Conclusions: CD in RV was a useful marker for identifying high‐risk patients with BS. CD in the RV, especially in the RVOT epicardium, may be related to arrhythmias in BS. (J Cardiovasc Electrophysiol, Vol. 21, pp. 688‐696, June 2010)