1,721,034 research outputs found
Left Atrial Anatomy and Function After Atrial Fibrillation of Brief Duration in Hypertrophic Hearts
No full textThe aim of the study was to evaluate the influence of left ventricular (LV) hypertrophy on left atrial (LA) electrical and mechanical function after cardioversion atrial fibrillation (A-Fib) ofbrief duration. Study group A included 100 patients with a first diagnosis of hypertension who had a moderate LV hypertrophy. The patient population included 64 men and 36 women with a mean age of 55 ±7 years who were hospitalized because of A-Fib and were cardioverted with external DC shock. Control group B included 100 patients without cardiac hypertrophy cardioverted because of lone A-Fib. Atrial function and size were assessed by Doppler echocardiography and the following parameters were measured: transmitral peak A velocity, atrial filling fraction, atrial ejection force, peak E velocity, deceleration time, and isovolumic relaxation time, LA maximal and minimal volume, and LV cardiac mass index. Baseline echocardiography showed that LA diameters and volumes were enlarged in all patients during A-Fib. After the restoration of sinus rhythm LA diameters and volumes decreased and the reduction was more evident in group B compared to group A. LA function as a continuous variable was negatively related to LV mass index (r = –0.77), LA diameter (r = –0.66 and r = –0.69 for the superoinferior diameter), LA maximal volume (r = –0.61) and LA minimal volume (r = –0.55) (all p <0.01).Atrial ejection force as a continuous variable was positively related to age (r = 0.78), peak A wave velocity (r = 0.71), systolic blood pressure (r = 0.51), and IVRT (r =0.41) (all p <0.01).Hypertrophy influenced the recovery of atrial function after cardioversion of A-Fib. Atrial function was reduced in patients with LV hypertrophy even after A-Fib of brief duration
The relationship between personality, socio-economic factors, acute life stress and the development, spontaneous conversion and recurrences of acute lone atrial fibrillation.
No full textAims The present study was designed to establish the relationship between personality factors, socio-economic factors and acute life stress with development, spontaneous cardioversion and recurrences of acute lone atrial fibrillation.Methods The study group consisted of 116 patients with lone atrial fibrillation cardioverted within 48 h of the onset of arrhythmia; they underwent a series of cognitive tests to evaluate acute psychological stress and personality type. The socio-economic status and other covariates (alcohol consumption, smoking, andbody mass index) were investigated. A control group, age- and sex-matched, was selected and compared. In the logistic regression analysis, the presence of spontaneous conversion to sinus rhythm was used as the dependent variable.Independent variables were indicator variables representing categories of stress, Type A behaviour pattern, coffee consumption and body mass index. Variables considered for logistic analysis were only those with independent prognostic value.Results. Type A behaviour pattern was found in 23 (20%) patients with atrial fibrillation and in 11 (9%) controls (P<0.001). The mean score among patients with atrial fibrillation was 8 + 2.7, while in control subjects it was 5.5+ 2. The mean acute life stress score among patients with atrial fibrillation was 56+ 33, while in controls it was 34+27 (P<0.01). Spontaneous conversion of atrial fibrillation to sinus rhythm was observed in 72 patients (63%). In univariate analysis alcohol consumption, income, education and smoking habits did not affect spontaneous conversion. High coffee consumption (OR 0.3 95% CI 0.11-0.49; P=0.008) and high body mass index were associated with a significantly greater risk of atrial fibrillation (OR 1.5 95% CI 1.2-1.7).Conclusions Type A behaviour pattern and acute life stress affect the development and spontaneous conversion of atrial fibrillation. Patients with acute stress showed the highest probability of spontaneous conversion followed by patients with Type A behaviour. Other socio-economic factors affect spontaneousconversion and recurrences of lone atrial fibrillation to a lesser extent
Left atrial size after cardioversion for atrial fibrillation: effect of external DC shock
No full textOBJECTIVE: The aim of this study was to evaluate the effect of external direct current (DC) shock on left atrial (LA) dimension and volumes after cardioversion for atrial fibrillation, and the relation between LA size and atrial function. METHODS: We evaluated 180 patients who were randomly cardioverted with DC shock (90 patients) or drugs (90 patients). Echocardiographic evaluations included LA size and volumes. LA passive and active emptying volumes were calculated, and LA function was measured as atrial ejection force. Changes in LA diameters and volumes were correlate with atrial systolic function. RESULTS: The LA was dilated in all patients during arrhythmia and decreased after the restoration of sinus rhythm. The entity of reduction was different in the 2 groups of patients. LA maximal and minimal volumes were increased after DC shock as compared with patients treated with drugs (LA maximal volume 34 +/- 4 vs 31 +/- 5; P <.01; LA minimal volume 18 +/- 2.6 vs 15 +/- 3.6; P <.01). The atrial function was also depressed after DC shock and the delay in the recovery of atrial contractility was related to LA dilation. Patients treated with drugs had a higher atrial ejection force that was associated with a more marked reduction in LA maximal volume after the restoration of in sinus rhythm. A relationship between LA volumes and atrial ejection force was observed in the group of patients with depressed atrial mechanic function (r = -0.78; P <.001). The active emptying fraction was lower, although not significantly, in this group, whereas the conduit volume was increased. CONCLUSION: External DC shock induced a depressed atrial mechanic function in many patients and this was associated with a persistence of LA dilation
Atrial stunning, inflammation and nutritional status after cardioversion from atrial fibrillation
No full textBACKGROUND: Conversion of atrial fibrillation (A-Fib) to sinus rhythm is associated with transient mechanical dysfunction of left atrium and appendage, termed atrial stunning. OBJECTIVES: The aim of the present study was to evaluate the relationship between nutritional status and atrial stunning after conversion of A-fib. METHODS: Fifty-eight hemodynamically stable patients referred for cardioversion for lone AF were included in this study. To assess nutritional status and inflammation we measured: hemoglobin, erythrocyte mean cell volume, increased transferrin, decreased percent transferrin saturation and ferritin, albumin, CRP and Fe. Usual dietary intake was assessed with the use of a semi-quantitative food frequency questionnaire. LA function was assessed using peak atrial filling velocity, atrial ejection force and peak of emptying and filling velocities of left atrial appendage. RESULTS: Patients were categorized in 4 groups according to value of CRP and Fe. Patients with normal value of CRP and normal value of Fe and patients with elevated CRP but normal value of Fe showed no difference in parameters of atrial function. On contrary patients with reduced value of Fe showed significantly reduced parameters of atrial function. CONCLUSIONS: Data of the present study showed that patients with a reduction of Fe present a marked dysfunction of atrial contractility in comparison with other groups. We cautiously hypothesize an iron mechanism. The hemodynamic stress due to A-Fib can generate highly toxic hydroxyl radicals. These oxygen free radicals probably damage cells by oxidating various cell components and could be important in inducing myocardial stunning after A-Fib
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Genotoxicity of N-acryloyl-N'-phenylpiperazine, a redox activator for acrylic resin polymerization
No full textN-Acryloyl-N'-phenylpiperazine is a promoter of redox reactions synthesized recently, and proposed as an activator for the polymerization of acrylic resins for biomedical use. The chemical was analyzed for different genotoxicity endpoints, to obtain both information on its possible mutagenic/carcinogenic potential and a model analysis of a tertiary arylamine, which belongs to a class of chemicals commonly used as polymerization accelerators in the biomaterial field. The genotoxicity endpoints considered were: gene mutation in the Salmonella test; structural and numerical chromosome alterations in Chinese hamster V79 cells, evaluated by the micronucleus test together with an immunofluorescent staining specific for kinetochore proteins; in vitro and in vivo DNA damage, evaluated in V79 cells and in mouse liver by the alkaline DNA elution technique. On the whole, the results indicate that N-acryloyl-N'-phenylpiperazine is to be regarded not so much as a DNA-damaging agent, but as a genomic mutagen. Indeed, it was not mutagenic in Salmonella (though its toxicity did not allow testing concentrations over 70 micrograms/plate), and it was weakly positive in inducing chromosomal fragmentation in vitro (one positive, not dose-related, result out of five different doses tested) and in vivo DNA damage (increases in DNA elution rate never doubling control values). The chemical was, however, clearly positive (with dose-dependent effects up to about 25 times the control value) in causing numerical chromosome alterations, at the maximal non-toxic dose
Genotoxicity of N-Acryloil-N-phenylpiperazine, a redox activator for acrylic resin polymeration
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