Approximate resonance states in the semigroup decomposition of resonance evolution

The semigroup decomposition formalism makes use of the functional model for $C_{.0}$ class contractive semigroups for the description of the time evolution of resonances. For a given scattering problem the formalism allows for the association of a definite Hilbert space state with a scattering resonance. This state defines a decomposition of matrix elements of the evolution into a term evolving according to a semigroup law and a background term. We discuss the case of multiple resonances and give a bound on the size of the background term. As an example we treat a simple problem of scattering from a square barrier potential on the half-line.Comment: LaTex 22 pages 3 figure

Arrhythmic Mitral Valve Prolapse: New Menaces of the Known Disease

Mitral  valve prolapse  (MVP) has  long  been  the subject  of intense  discussions regarding the prognosis and  follow-up tactics.  In most  cases,  this condition has a benign prognosis. However, recent autopsy and follow-up studies have shown risks of developing  sudden cardiac death (SCD) in some subgroups of patients who have this clinical phenomenon. The proposed  literature review uses the population  of patients with MVP with the highest probability  of developing  life-threatening ventricular tachyarrhythmias. Patients with the presence of a complex  of changes, including  bicuspid  MVP, negative T waves in the inferior and lateral leads on a standard  12-lead electrocardiogram (ECG), and a special anatomical  phenomenon called mitral annular  disjunction  (MAD), are at high  risk of developing  ventricular  ectopias  and VSS.  A reflection  of the high  risk of SCD  in such patients  is the increase of ventricular ectopy according to Holter monitoring. The presence of a bicuspid  MVP and the MAD  phenomenon, which is a separation  of the line of attachment  of the posterior mitral leaflet from the basal inferior wall segment  towards  the atrial wall, determines the presence of a special form of MVP,  the so-called  arrhythmogenic MVP.  Hence,  in most cases MVP has a benign  prognosis. However, patients with the aforementioned ar- rhythmic  MVP  signs  must  be given  particular  attention  and  annual  follow-up including  ECG  control,  Holter  monitoring and  echocardiographic examination of the heart to reduce the risk of ventricular tachyarrhythmias and SCD development

SAFETY OF AMIODARONE USAGE IN PATIENTS WITH WOLFF-PARKINSON-WHITE SYNDROME AND ATRIAL FIBRILLATION

Amiodarone is one of the basic antiarrhytmic drugs for atrial fibrillation treatment. However application of amiodarone in patients with atrial fibrillation and Wolff-Parkinson-White syndrome can induce ventricular fibrillation. Amiodarone usage in these patients should be accompanied by readiness for performance of resuscitation. This is confirmed by clinical case presentation

On the similarity of Sturm-Liouville operators with non-Hermitian boundary conditions to self-adjoint and normal operators

We consider one-dimensional Schroedinger-type operators in a bounded interval with non-self-adjoint Robin-type boundary conditions. It is well known that such operators are generically conjugate to normal operators via a similarity transformation. Motivated by recent interests in quasi-Hermitian Hamiltonians in quantum mechanics, we study properties of the transformations in detail. We show that they can be expressed as the sum of the identity and an integral Hilbert-Schmidt operator. In the case of parity and time reversal boundary conditions, we establish closed integral-type formulae for the similarity transformations, derive the similar self-adjoint operator and also find the associated "charge conjugation" operator, which plays the role of fundamental symmetry in a Krein-space reformulation of the problem.Comment: 27 page

LEFT VENTRICLE TORSION IN AN IDIOPATHIC HIS LEFT BUNDLE BRANCH BLOCK

The role of left His bundle branch block (LBBB) in normal systolic function of the left ventricle (LV) remains under investigated for the global deformation and torsion.Aim. To investigate on the global deformity of the LV in longitudinal direction by circumference, and its torsion, in patients with idiopathic LBBB with saved LV ejection fraction (EF).Material and methods. Totally, 50 persons with idiopathic LBBB studied, with the mean duration of QRS 153±24,5 ms. Comparison group included 18 persons with no LBBB. All patients underwent echocardiography (Echo) with assessment of intracardiac hemodynamics, deformity measurement by Speckle tracking imaging, with evaluation of torsion and rotation dynamics of the LV. Results. There were no significant differences in idiopathic LBBB group comparing to the controls, by the value of end-diastolic volume (respectively, 110,5±33,5 mL vs 95,3±23,5 mL, р=0,1) and EF LV (61,3±9,5% vs 64,4±9,4%, р=0,2). In idiopathic LBBB group comparing to controls, there was decrease of global LV deformation in longitudinal direction (respectively, -14,6±3,98% vs -8,4±3,10%, р=0,0006) and by circumference at basal segments (-7,02±4,40)% vs -10,6±4,18%, р=0,0075). It was found that in idiopathic LBBB there is disordered rotation at basal segments level (-2,95±4,36º vs -6,10±3,01º, р=0,019) and the torsion of LV as well (7,52±5,48º vs 13,1±5,18º, р=0,001).Conclusion. Disordered conduction in LBBB is followed by impaired rotation and torsion, regardless of the saved systolic function

Heart failure with preserved ejection fraction: the role of diastolic stress test in diagnostic algorithms

Heart failure (HF) with preserved ejection fraction (HFpEF) is currently the most common type of this condition, especially among elderly patients. Despite the preserved left ventricular (LV) and a moderate increase in natriuretic peptide, patients  with HFpEF have the same out-of-hospital mortality as those with HF with reduced ejection fraction (HFrEF). Diagnosis of HFpEF is difficult due to nonspecific symptoms, expensive blood tests, and questionable rest echocardiographic data on diastolic function. In addition, the reason for poor diagnosis of HfpEF in clinical practice may be old age and comorbidities, which can also cause nonspecific symptoms of moderate chronic shortness of breath, weakness, and palpitations. The consequence is the detection of HFpEF only in every fourth patient with an acute or chronic heart failure. The use of simplified clinical diagnostic protocols along with a non-invasive ultrasound stress test can help overcome the existing problems in the diagnosis of HFpEF

DIAGNOSTICS AND TREATMENT OF MITRAL VALVE PROLAPSE

The mitral valve prolapse (MVP) is one of the most inconsistent diagnose. In the most cases patients with MVP have the good long-term prognosis, and therapy is aimed at reduction in psychovegetative dysfunction. Careful follow-up and timely cardiosurgical correction should be performed, if necessary, in patients with classical MPV. The choice method in these cases is the mitral valve plasty

LEFT ATRIAL FUNCTION: MODERN ASSESSMENT METHODS AND CLINICAL SIGNIFICANCE

Assessment of the left atrial (LA) function is important aspect of comprehensive cardiovascular system estimation. Many cardiac diseases make an impact to LA work either by direct affect on myocardium or hemodynamic condition changing. It is considered, LA and left ventricle diastolic pressure is interrelated, thus without mitral valve disease LA expanding is a sign of LV filling pressure augmentation. Examination of LA size and function by analysis of atrial reservoir, conduit, and booster pump can predict cardiovascular outcomes in patients with cardiomyopathy, ischemic heart disease and valvular heart disease. The last two decades gave new technologies to accurate and comprehensive LA mechanics estimation, in the first place related to tissue Doppler imaging. Atrial strain and strain rate obtained using two-dimensional speckle-tracking echocardiography have proved to be feasible and reproducible techniques to evaluate LA mechanics.In physiological settings, LA is a highly expandable chamber with relatively low pressures. However in the presence of acute and chronic injury, LA wall stretches. LA stretching is a hallmark of structure changing with myocardial fibrosis and has influence on LA strain and strain rate. LA strain estimation could be useful in the prediction of sinus rhythm restoration and maintenance after cardioversion and catheter ablation. Low values of global longitudinal LA strain indicate irreversible LA remodeling and are related to the atrial fibrillation progression from paroxysmal to permanent forms. The most interesting in these circumstances is the potential contribution of echocardiography to thromboembolic risk stratification in atrial fibrillation and invasive procedures such as atrial ablation. Therefore, at present, the main task is to understand the ways of clinical application of data  obtained during the LA study