Long-term effectiveness of right septal pacing vs. right apical pacing in patients with atrioventricular block

AbstractBackgroundLong-term right ventricular apical (RVA) pacing increases the risk of heart failure (HF) by inducing ventricular dyssynchronization. Although recent studies suggest that right ventricular septal (RVS) pacing results in improved short-term outcomes, its long-term effectiveness remains unclear.Methods and resultsThis study investigated 149 consecutive patients who underwent implantation of a dual chamber pacemaker for atrioventricular block with either RVS-pacing between July 2007 and June 2010 or RVA-pacing between January 2003 and June 2007. The endpoint was defined as death and hospitalization due to heart failure (HF). The rates of mortality and hospitalization due to HF were significantly lower in the RVS-pacing group than that in the RVA-pacing group (event free RVS: 1 year, 98% and 2 years, 98%; RVA: 1 year, 85% and 2 years, 81%; p<0.05). None of the patients died from HF in the RVS-pacing group, while 4 patients died from HF in the RVA-pacing group within 2 years after pacemaker implantation. The paced QRS interval was significantly shorter with RVS pacing than with RVA pacing at different times after pacemaker implantation (RVS: immediately 157.8±24.0ms, after 3 months 157.3±17.5ms, after 6 months 153.6±21.7ms, after 12 months 153.6±19.4ms, after 24 months 149.3±24.0ms vs. RVA: immediately 168.3±23.7ms, after 3 months 168.7±26.0ms, after 6 months 168.0±22.8ms, after 12 months 171.2±22.3ms, after 24 months 176.1±25.5ms; p<0.05).ConclusionsRVS pacing is feasible and safe with more favorable clinical benefits than RVA pacing

Scanning Electron Microscopic Investigations of the Shape of Toothbrush Filaments with Various Brushing Techniques I. The most effective case of plaque removal

Using 30 second-year students of the Matsumoto Dental College, School of Dental Hygiene as subjects, we performed investigations on toothbrush filament shape changes while using 4 test toothbrushes and 4 different brushing techniques over 2 week periods. Also, observation by scanning electron microscopy was done for the toothbrush which yielded the best plaque removal. The results were as follows: 1. The edge of the brush filament was worn almost rectangularly along the longitudinal axis after 2 weeks of using the Bass and scrub techniques. 2. The filament edge tended to become sharper with the rolling and modified Stillman techniques. The round-cut and moving area of the toothbrush body were worn significantly using the rolling and modified Stillman techniques. 3. The toothbrush filaments with every brushing technique were worn significantly. Deep ditches, scratches and peeling were frequently observed with the rolling and modified Stillman techniques

Effect of Implantable Cardioverter-defibrillator Therapy for Ventricular Fibrillation Patients with Out-of-hospital Cardiac Arrest

Survivors of ventricular fibrillation out-of-hospital cardiac arrest（VF-OHCA）due to potentially reversible causes such as acute coronary syndrome（ACS）, vasospastic angina and electrolyte abnormalities are considered low risk for recurrent arrhythmia. Accordingly, implantable cardioverter-defibrillator therapy is not routinely recommended in such patients. We investigated the risk of mortality and the value of ICD therapy for VF-OHCA. Among 2,248 cardiopulmonary arrest patients presenting at our hospital, we retrospectively investigated 110 patients with VF-OHCA who were admitted for treatment. We divided the patients based on ICD（n＝71） or No-ICD status（n＝39）, and on reversible cause（n＝70） or irreversible cause（n＝40）. The groups were compared for baseline characteristics, mortality and ICD therapies. Patients with a reversible cause had a significantly lower rate of ICD implantation than those with an irreversible cause（P＝0.03）. Males in the ICD group presented more frequently than those in the No-ICD group, and cardiac mortality in patients with acute coronary syndrome was significantly lower with ICD therapy than without ICD（P＝0.04）. The rate of appropriate ICD therapies with a reversible cause was 28％, and the first ICD therapy was highest within 1 year post-implantation. Patients with VF-OHCA due to a reversible cause remain at high risk of recurrent ventricular arrhythmias, suggesting that ICD implantation is a reasonable approach in such cases

Relationship between sintering temperature and transformation of phase for Y2O3 partially stabilized zirconia

The objective of this study was to verify the stability of Y2O3 partially stabilized zirconia (zirconia) sintered at 1,350℃ and 1,450℃ in a simulated oral environment over a long period of time. After sintering, zirconia was immersed in physiological saline, 1% lactic acid solution, and 1% malic acid solution which can be produced in the oral cavity for 3 or 6 months. The amount of yttrium released, and transformation from the tetragonal phase to monoclinic phase by X–ray diffraction were evaluated. Using X–ray diffraction, the monoclinic phase hardly existed for zirconia sintered at 1,350℃; however, for zirconia sintered at 1,450℃, the monoclinic phase existed. The amount of yttrium released was small after exposure to both 1% lactic acid solution and 1% malic acid solution for zirconia sintered at 1,350℃. In contrast, it showed a maximum relase after exposure for 6 months form zirconia sintered at 1,450℃. Based on the X–ray diffraction, the monoclinic phase did not increase for zirconia sintered at 1,350℃ after exposure to 1% lactic acid solution and 1% malic acid solution for 3 and 6 months. However, there was marked transformation for zirconia sintered at 1,450℃ after exposure for 6 months. The frequency of the monoclinic crystal structures increased with the release of yttrium, as confirmed by the results of X–ray diffraction and measurement. As a result of structural observation, the crystal grain size of zirconia sintered at 1,350℃ was finer than that sintered at 1,450℃. It was clarified that zirconia sintered at 1,350℃ was more suitable than that sintered at 1,450℃ as an implant material

Head-up Tilt Test May Be Useful for Determining Permission of Flight for Regular Passenger Aircraft Pilots with Vasovagal Syncope

To determine the permissibility of piloting an aircraft with vasovagal syncope （VVS） is a complex responsibility, because it is difficult to evaluate VVS quantitatively. There are no clear guidelines for aircraft pilots with VVS. In some facilities, Head-up Tilt Test （HUTT） is used to determine its reproducibility and treatment effect. In most cases, permission is dependent on the strict examinations by specialists and judgement of the committee established for each country. Therefore, we assessed pilots with VVS and designed an algorism of permission for piloting an aircraft. Here, we describe 7 consecutive regular passenger aircraft pilots with VVS who were restricted to fly. All patients were men and their mean age was 37 years. All pilots were permitted to fly after at least two or more tilt-tests. The observation period was two years after flight permission. None of the pilots in the present study fainted after receiving flight permission. We can make a risk stratification to determine hypotensive susceptibility by multiple tilt tests. Based on the results of multiple HUTT, we can more quantitatively make the judgement as to whether the pilot’s VVS is well managed

Epicardial Adipose Tissue in the Right Atrium Is Associated with Progression of Atrial Fibrillation and Recurrence after Pulmonary Vein Catheter Ablation in Patients with Atrial Fibrillation

An increase in epicardial adipose tissue（EAT）in the left atrium（LA）predicts the progression of atrial fibrillation（AF）and AF recurrence after pulmonary vein catheter ablation（CA）. We hypothesized that EAT in the right atrium（RA）is also associated with the progression of AF and post-CA AF recurrence. Using 128-slice multidetector computed tomography, EAT volume and atrial volume were measured 3-dimensionally before CA in 68 patients who had proven AF（paroxysmal AF, 42; persistent AF, 26; mean age, 65±11 years; 42.6％ female）with successful CA and 21 volunteers with sinus rhythm（age, 63±13 years; 52.3％ female）. In both atria, EAT and atrial volumes were largest in patients with persistent AF, followed, in order, by those with paroxysmal AF, and then healthy volunteers（P＜0.001）. Increased EAT and atrial volumes in both atria predicted persistent AF（P＜0.001）. Fifteen patients had AF recurrence（22.1％）during the 2-year period after CA. Increased EAT volume in both atria were independent predictors for AF recurrence, and a RA EAT volume≥6.2ml was an independent predictor, with a hazard ratio of 5.47（95％ confidence interval, 1.2-24.3; P=0.03）. The combination of EAT and atrial volume in both atria was a more powerful independent prognostic factor, with a hazard ratio of 4.8（95％ confidence interval, 1.7-3.7; P=0.003）, and a sensitivity of 60％ in 9 of 15 patients, and specificity of 81.1％ in 43 of 53 patients,（P=0.003）. RA EAT is associated with the progression of AF and post-CA AF recurrence