Different behaviour of NOX2 activation in patients with paroxysmal/persistent or permanent atrial fibrillation.

BACKGROUND: NOX2, the catalytic subunit of NADPH oxidase, is suggested to play a role in favouring the occurrence of atrial fibrillation (AF) after cardiac surgery via formation of reactive oxidant species. However, its role in spontaneous AF is still unclear. OBJECTIVE: To define the role of NOX2 and isoprostanes, a marker of oxidative stress, in the different settings of AF. METHODS: The study was performed on 174 patients with AF (82 with paroxysmal/persistent AF and 92 with permanent AF) and 90 controls matched for sex, age and atherosclerotic risk factors. Urinary isoprostanes and serum levels of soluble NOX2-derived peptide (sNOX2-dp) were measured in each patient. RESULTS: Urinary isoprostanes and sNOX2-dp concentrations were significantly higher in patients with paroxysmal/persistent AF than in those with permanent AF and controls. Compared with controls, patients with permanent AF showed a weak increase in sNOX2-dp and no difference in isoprostanes. Multivariable analyses demonstrated that baseline values of sNOX2-dp and urinary isoprostanes were independently associated with the type of AF (paroxysmal/persistent vs permanent; ß=-224, p=0.007 and ß=-231, p=0.005, respectively). A significant correlation between sNOX2-dp levels and urinary excretion of isoprostanes was also detected (R=0.707, p<0.001). CONCLUSIONS: This study provides evidence that NOX2 is upregulated only in patients with paroxysmal/persistent AF and is responsible for overproduction of isoprostanes. This finding warrants further study to see if inhibition of NOX2 may reduce the risk of paroxysmal/persistent AF.

[Metalloproteinase activity of the blood in patients with arterial hypertension with paroxysmal form of atrial fibrillation].

Aim of the study was to investigate interrelationship between serum markers of myocardial fibrosis: matrix metalloproteinase -1 (MMP-1), tissue inhibitor of metalloproteinase-1 (TIMP-1) and parameters of echocardiography in patients with arterial hypertension (AH) and paroxysmal form of atrial fibrillation (n=39). We revealed positive correlation of levels of TIMP-1 with thickness of interventricular septum in diastole (r=0,47, p=0,02), peak velocity of late filling of the right ventricle (r=0,46, p=0,01), and negative relation between MMP-1 levels and degree of mitral and tricuspid regurgitation (r=0,43, p=0,005 and r=0,38, p=0,04, respectively). In the group of patients with increased left ventricular myocardial mass index (LVMMI) TIMP-1 level was significantly higher than in patients with normal LVMMI (p < 0,05). In the group combining patients with concentric and eccentric LV hypertrophy TIMP-1 level was significantly higher than in the group combining patients with LV concentric remodeling and normal geometry (p < 0,05). No correlations were revealed between MMP-1 and TIMP-1 levels and parameters of diastolic dysfunction. In patients with AH increase of serum concentrations of TIMP-1 was associated with increased thickness of interventricular septum, increase of LVMMI, and with prognostically unfavorable types of LV remodeling.

Paroxysmal supraventricular tachycardia in children: the role of infectious diseases and its relationship to serum enzyme.

The records of 28 children whose first episode of paroxysmal supraventricular tachycardia occurred before 12 years (median age 10 months) were reviewed. There were 17 males and 11 females. In 17 cases the first attack occurred before the first year and in 11 of these it occurred after the first year. One case had congenital heart disease (ASD). The WPW syndrome was diagnosed in 3 cases. When first seen, most of the infants presented with signs of incipient or manifest congestive heart failure. In almost nine-tenth of cases there was an increased of serum enzymes (lactic dehydrogenase, creatine-phosphokinase and glutamic oxaloaccetic transaminase. Digitals was effective against congestive heart failure and when continued, might prevent failure during subsequent attacks. Antiarrhythmic agents other than digitals were not used. It is recommended to continue digitalis treatment for at least one year in all patients with SVT, whether or not the first episode terminated spontaneously.