Atrial electromechanical coupling intervals in pregnant subjects

Atrial fibrillation (AF), which is the most common cardiac arrhythmia, may cause serious symptoms and impair quality of life.1 The development of AF is associated with many risk factors, including age, male gender, hypertension, heart failure, valvular disease, diabetes mellitus (DM) and left atrial (LA) enlargement.2-4 Electrical and/or mechanical remodelling of the atria is thought to be a pathophysiological characteristic of AF.5The pregnant state may be pro-dysrhythmic. This is related to the cardiovascular, hormonal, haemodynamic and autonomic changes during healthy pregnancy. Levels of oestrogen and β-human chorionic gonadotropin increase dramatically. Haemodynamic changes include an increase in circulating blood volume, which increases cardiac output. This results in myocardial stretch and an increase in cardiac end-diastolic volume. High plasma catecholamine concentrations and adrenergic receptor sensitivity increase sympathetic tone. All these changes in pregnant women may make them more prone to dysrhythmogenesis.6Most pregnant women complain of palpitations, dizziness and even syncope, but these symptoms are rarely associated with cardiac dysrhythmias. AF is the most common clinically significant cardiac arrhythmia in the general population but it is rarely seen in pregnant women. When it occurs, it can represent a benign, self-limited lone episode of AF or may be secondary to congenital or rheumatic valvular disease, hypertrophic cardiomyopathy, thyroid disease, or pre-excitation syndrome.Two simple electrocardiogram (ECG) markers, namely maximum P-wave duration (Pmax) and P-wave dispersion (PD), have been used to evaluate intra- and inter-atrial conduction times and the inhomogeneous propagation of sinus impulses, which are well-known electrophysiological characteristics of the atrium prone to fibrillation.7,8 Prolonged Pmax and PD have been reported to represent an increased risk for AF in patients with no underlying heart disease.7,8 Besides, evidence from laboratory and epidemiological research suggests that systemic inflammation may play a role in AF aetiology.9 It has also been demonstrated that atrial electromechanical coupling, measured by tissue Doppler imaging (TDI), as significantly longer in patients with paroxysmal AF than in control groups.10,11To our knowledge, no study evaluating PD and atrial electromechanical coupling has been investigated in pregnant subjects without additional systemic disease. Therefore, in this study we aimed to examine atrial electromechanical coupling and PD, reflecting inter-atrial conduction times in pregnant subjects.     

Disturbed Left Atrial Function is Associated with Paroxysmal Atrial Fibrillation in Hypertension

Background

Hypertension is the most prevalent and modifiable risk factor for atrial fibrillation. The pressure overload in the left atrium induces pathophysiological changes leading to alterations in contractile function and electrical properties.

Objective

In this study our aim was to assess left atrial function in hypertensive patients to determine the association between left atrial function with paroxysmal atrial fibrillation (PAF).

Method

We studied 57 hypertensive patients (age: 53±4 years; left ventricular ejection fraction: 76±6.7%), including 30 consecutive patients with PAF and 30 age-matched control subjects. Left atrial (LA) volumes were measured using the modified Simpson''s biplane method. Three types of LA volume were determined: maximal LA(LAVmax), preatrial contraction LA(LAVpreA) and minimal LA volume(LAVmin). LA emptying functions were calculated. LA total emptying volume = LAVmax−LAVmin and the LA total EF = (LAVmax-LAVmin )/LAVmax, LA passive emptying volume = LAVmax− LAVpreA and the LA passive EF = (LAVmax-LAVpreA)/LAVmax, LA active emptying volume = LAVpreA−LAVmin and LA active EF = (LAVpreA-LAVmin )/LAVpreA.

Results

The hypertensive period is longer in hypertensive group with PAF. LAVmax significantly increased in hypertensive group with PAF when compared to hypertensive group without PAF (p=0.010). LAAEF was significantly decreased in hypertensive group with PAF as compared to hypertensive group without PAF (p=0.020). A'' was decreased in the hypertensive group with PAF when compared to those without PAF (p = 0.044).

Conclusion

Increased LA volume and impaired LA active emptying function was associated with PAF in untreated hypertensive patients. Longer hypertensive period is associated with PAF.     

Evaluation of the Relation Between Hepatic Fibrosis and Basic Laboratory Parameters in Patients With Chronic Hepatitis B Fibrosis and Basic Laboratory Parameters

Background:

The hepatitis B virus is an important healthcare problem. According to current clinical practice, a liver biopsy is required for the diagnosis and treatment of chronic liver disease. However, a liver biopsy is an invasive, inconvenient procedure, which requires an expert pathologist opinion. Therefore requirement of biochemical tests, which are considered to indicate hepatic fibrosis and may be repeated easily, increases gradually today.

Objectives:

This study evaluated the correlation between hepatic fibrosis and routine laboratory values in patients with chronic hepatitis B.

Patients and Methods:

The files of 456 patients with CHB (chronic hepatitis B) who were referred to the infectious diseases and clinical microbiology clinic between January 2009 and March 2012 were screened retrospectively. Liver biopsy samples were examined according to Ishak scoring. Laboratory parameters and histopathology reports were recorded, and correlations between the fibrosis grade and laboratory parameters were analyzed.

Results:

There were 320 male and 136 female patients, with a mean age 36.7 ± 12.1 years. According to liver biopsy results, a low fibrosis score (stage 0-2) was detected in 281 patients (61.6%), and a high fibrosis score (stage 3-5) was detected in 175 patients (38.4%). Patients with a high fibrosis score had significantly higher ALT (alanine amino transferase), AST (aspartate aminotransferase), and HBV-DNA values and a significantly lower platelet count compared with those with a low fibrosis score (P = 0.001, 0.001, 0.025, and 0.001, respectively). A positive correlation was detected between the fibrosis score and age, BMI, HAI, ALT, and AST values, and a negative correlation was detected between the fibrosis score and albumin and platelet counts. In the regression analysis performed to evaluate the factors associated with high-stage fibrosis, fibrosis was determined to be associated with thrombosis, ALT, and gender. The results of the regression analysis demonstrated that the risk of fibrosis was 4.6 fold higher in men.

Conclusions:

According to the results obtained in our study, advanced age, higher BMI, AST, ALT, and HBV-DNA levels, and low albumin and platelet levels are correlated with advanced fibrosis in patients with CHB.     

Serum prolidase activity,oxidative stress,and nitric oxide levels in patients with bladder cancer

Objectives

Prolidase is a member of the matrix metalloproteinase family. It plays a major role in collagen turnover, matrix remodeling and cell growth. Nitric oxide (NO) regulates many processes such as collagen synthesis and matrix remodeling. Thus, NO may augment angiogenesis, tumor invasion, and metastasis. The aim of this study was to investigate total antioxidant status (TAS), malondialdehyde (MDA) and NO levels in patients with bladder cancer and to determine their relationship with prolidase activity.

Design and methods

Thirty-five patients with bladder cancer and 32 controls were enrolled. Serum TAS, MDA, prolidase activity and NO levels were determined.

Results

Serum prolidase activity, NO levels and MDA levels were significantly higher in bladder cancer than controls (all, P < 0.05), while TAS levels were significantly lower (P < 0.05).

Conclusions

Our results show that increased prolidase seems to be associated with increased NO levels and oxidative stress along with decreased antioxidant levels in bladder cancer.

     

Mean platelet volume is elevated in patients with patent foramen ovale

Introduction

Platelets play a major role in thromboembolic events. Increased mean platelet volume (MPV) indicates higher platelet reactivity and also a tendency to thrombosis. Patent foramen ovale (PFO), persistence of the fetal anatomic shunt between right and left atria, is strongly associated with cryptogenic stroke. The aim of this study is to determine the relationship between MPV and PFO and if such an association exists, whether higher MPV levels may require antiplatelet therapy before a thromboembolic event happens, together with a literature review.

Material and methods

Thirty patients (15 women, 15 men), free of any cerebrovascular events, were diagnosed with PFO by transesophageal echocardiography (TEE), enrolled as the study group. Thirty consecutive patients (16 women and 14 men), who were diagnosed as normal in TEE, were enrolled as the control group. These two groups were compared according to MPV and anatomical features of the right atrium.

Results

There was no significant difference between study and control groups in clinical features and also no difference was observed in platelet counts; however, MPV in the PFO group was significantly higher than the control group (8.38 ±0.93 fl and 7.45 ±0.68 fl respectively).

Conclusions

Our results indicate that elevated MPV may be detected in patients with PFO. This might be one of the explanations for the relationship between PFO and cryptogenic stroke; however, larger cohorts are warranted in order to define further mechanisms.     

The processing of ultrafine-grained Mg tubes for biodegradable stents

An investigation was carried out on equal-channel angular pressing (ECAP) and extrusion processing of a ZM21 Mg alloy to obtain an improved candidate material for the manufacturing of biodegradable Mg stents. Ultrafine-grain size billets of the ZM21 alloy were obtained by two-stage ECAP aimed at achieving an initial refining of the structure at 200 °C and then reaching the submicrometer grain size range by lowering the processing temperature down to 150 °C. The investigation revealed a significant improvement in the properties of the ECAP-treated samples compared with the starting coarse-grained ZM21 alloy. The 0.2% yield strength rose from 180 to 340 MPa after 150 °C ECAP processing, while maintaining a fairly high tensile ductility. The ultrafine ZM21 alloy billets were then used for the extrusion of stent precursors having the form of small-size tubes. The grain size after extrusion remained in the submicrometer range while the hardness was revealed to be significantly higher than that of the coarse-grained ZM21 Mg alloy. It was demonstrated that processing of biodegradable Mg stent having an ultrafine-grained microstructure by ECAP and low-temperature extrusion is feasible and that the obtained products feature promising properties.