Vol 3, No 1 (2023)

BACKGROUND: In recent years, asymptomatic hyperuricemia (HU) has been found to have significant adverse effects on the cardiovascular system. Uric acid (UA) accumulation in cardiomyocytes may cause ionic and structural remodeling of the atria. One of the causes of increased UA and a significant risk factor for HU is polymorphism in the SLC2A9 gene, which encodes the GLUT9 protein, a highly specific urate transporter in proximal renal tubular cells.

AIM: To investigate the frequency of genotypes and alleles of the SLC2A9 gene rs734553 polymorphism and left atrium (LA) diameter in patients with arterial hypertension (AHT) and atrial fibrillation (AF).

MATERIALS AND METHODS: One hundred four patients, including 94 (90.4%) men and 10 (9.6%) women (aged 55 [45; 61] years old) were enrolled in the study. The patients were divided into the following groups: first — patients with AF (n = 13); second — patients with AHT and AF (n = 68); and third — patients with AHT (n = 23). The LA diameter equal to the LA anterior–posterior dimension on transthoracic echocardiography was taken into account as a characteristic of structural changes of the LA. All patients underwent instrumental, laboratory, and molecular genetic testing, including SLC2A9 gene rs734553 polymorphism using the polymerase chain reaction technique.

The data were presented as median, first and third quartiles, and absolute and relative frequencies. Differences between groups of patients were assessed using the Mann – Whitney U-test and Fisher and Pearson’s χ² test. The Kruskal–Wallis test was used to compare three independent groups. Differences were considered statistically significant at p < 0.05. The relationship between the quantitative and dichotomous variables was described using the rank-biserial correlation coefficient (rrb). The distribution of alleles and genotypes in the studied patient groups was tested for Hardy – Weinberg equilibrium and assessed using the χ² test.

RESULTS: There were no significant differences (p > 0.05) when comparing the LA diameter and the genotype of the SLC2A9 gene rs734553 polymorphism in all groups of patients. However, in Group 2, the LA diameter in the CC genotype (43 [42; 44] mm) patients and the AC genotype (40 [49; 43] mm) patients was determined to be larger than in the AA genotype ones (38 [38; 42] mm). In Group 1, the LA diameter in the AC genotype patients (40 [38; 42] mm) was larger than in the AA genotype ones (38 [34; 38] mm).

When studying the distribution frequency of genotypes and alleles of the SLC2A9 gene rs734553 polymorphism in patients with LA dilatation, we found that in the second group of patients, the AC genotype was significantly more common than in other groups (23.5%) (p = 0.004), and there was also a trend toward a higher incidence of AA (13.2%) and CC (14.7%) genotypes. However, it did not reach the criteria for statistical significance. It should be noted that in patients of the first group, LA dilatation was diagnosed only with the AC genotype (38.5%). Dilatation of the LA in patients of the third group was not detected.

CONCLUSIONS: In Group 1 patients (with AF), LA dilatation was observed only in the AC genotype ones. In Group 2 patients (with AHT and AF), LA dilatation was significantly more frequent (p = 0.004) in the AC genotype ones. The AC and CC genotype of the SLC2A9 gene rs734553 polymorphism was more frequent in Group 2 patients (with AHT and AF).

BACKGROUND: Catheter ablation (CA) is an established method for atrial fibrillation (AF) treatment. Up to 20% of patients with AF develop coronary artery disease (CAD) as a secondary diagnosis. The data on whether the CAD affects the efficacy of AF ablation is contrary, while arterial hypertension is a known risk factor for AF as well as for AF recurrence after the CA.

AIM: We conducted this research to assess the AF recurrence rate and its risk factors after the primary catheter AF ablation procedure in the different clinical groups including IdiopathicAF, AF concomitant to arterial hypertension (HTN) and AF concomitant to CAD.

MATERIALS AND METHODS: Patients who underwent 451 PVI procedures performed since January 2016 to December 2017 were screened for AH, CAD and other structural heart disease. Among them 153 pts were selected for the subsequent analysis and divided into 3 groups — IdiopathicAF, AF + AH, AF + CAD.

RESULTS: The presence of CAD (r = 0.313, p < 0.001), age (r = 0.224, p = 0.008), CHA2DS2-VASc score (r = 0.279, p = 0.001), history of MI (r = 0.240, p = 0.004), LA size (r = 0.204, p = 0.018) were correlated with the recurrence rate. In the AF + CAD group patients older than 65 years demonstrated dramatically lower AF-free survival rate (37.5%) in comparison to younger CAD population (75%, log-rank p < 0.001) as well as to younger and older non-CAD patients.

CONCLUSIONS: The presence of CAD should always attract the attention of physicians before considering the AF ablation as an option to treatment. Elderly CAD patients have the lowest ablation efficacy and the best strategy for this group (more extensive primary ablation or conversion to the permanent AF) needs to be studied.

Long QT syndrome is a disease associated with a high risk of sudden cardiac (arrhythmic) death. The frequency of sudden cardiac death is approximately 1: 100,000 young athletes, while autopsies often do not detect changes, which indicates a primary arrhythmogenic death. The article describes two clinical cases of young athletes with prolongation of the QT interval. The possible causes of the long QT syndrome and the difficulties of diagnosing this syndrome in children and adolescents involved in sports are discussed. Regardless of the reasons leading to the prolongation of the QT interval, there is a risk of arrhythmic events. Timely diagnosis of long QT syndrome is the way to the primary prevention of sudden cardiac death in young athletes.