This prospective study evaluates the impact of radiofrequency ablation (RFA) on cardiorespiratory indicators in patients with long-standing persistent atrial fibrillation admitted to the Heart Center UMC between January 2022 and April 2024 in Astana, Kazakhstan. The study aims to assess the functional cardiac benefits of RFA. Out of 717 registered atrial fibrillation patients, 104 were examined before and 3 months after ablation, focusing on cardiorespiratory parameters. A before-and-after analysis using linear mixed models was applied to evaluate changes in cardiorespiratory parameters post-RFA. Significant improvements were noted across various measures. VO₂ max increased from 11.5 ± 4.4 mL/kg/min to 18.0 ± 4.5 mL/kg/min (p < 0.001). Oxygen uptake improved from 7.2 ± 2.6 mL/beat to 11.0 ± 3.4 mL/beat (p < 0.001). The 6-min walking test distance rose from 306 ± 82 m to 400 ± 48 m (p < 0.001). METs increased from 4.4 ± 1.6 to 8.0 ± 1.3 (p < 0.001). Heart rate at peak exercise decreased from 175.5 ± 18.6 to 147.2 ± 12.3 beats per minute (p < 0.001). NT-proBNP levels decreased from 1357 ± 1182 to 415 ± 339 pg/mL (p < 0.001). Patients with persistent atrial fibrillation undergoing RFA showed functional improvements in CPET indicators such as VO₂ max, METs, O₂ pulse, heart rate, and the 6-min walking test. Improvements were also seen in Nt-proBNP analysis. These results emphasize the need for longitudinal follow-up to optimize outcomes and minimize medical risks.

Background. Patients with atrial fibrillation commonly experience decreased exercise tolerance, lower peak oxygen uptake (VO₂peak), and reduced overall physical activity levels, which negatively affect quality of life and cardiovascular outcomes. Catheter ablation has become an effective rhythm-control strategy, with growing evidence demonstrating improvements in functional capacity and cardiopulmonary efficiency after restoration of sinus rhythm. Methods. A systematic search was conducted in PubMed, Scopus, Web of Science, and Google Scholar for studies published between 2000 and 2025. Keywords included “atrial fibrillation,” “catheter ablation,” “exercise capacity,” “cardiorespiratory fitness,” and “reference values.” After screening 160 records, 48 peer-reviewed articles were included for qualitative analysis. Results. The reviewed studies consistently report that atrial fibrillation significantly reduces VO₂peak, exercise duration, and physical activity tolerance due to impaired cardiac output and rhythm irregularity. Catheter ablation is associated with significant improvements in cardiopulmonary performance, exercise capacity, and patient-reported quality of life. However, the extent of recovery varies among individuals. Importantly, the literature reveals a lack of population-specific reference values for cardiorespiratory fitness in Central Asian and Kazakh populations. Conclusion. Evidence supports the detrimental impact of atrial fibrillation on functional capacity and the beneficial role of catheter ablation in improving cardiorespiratory performance. Nevertheless, the absence of regional normative data represents a major limitation for clinical interpretation, highlighting the need for population-based studies in Kazakhstan and Central Asia.

Cardiorespiratory fitness (CRF) is a strong predictor of cardiovascular morbidity and mortality. This study aimed to describe age- and sex-specific reference values for CRF in healthy adults in Kazakhstan and to examine age-related changes in key physiological parameters, including peak heart rate and body mass index. The research included 3271 nonsmoking adults aged 20 to 59 years, free of health issues, who performed symptom-limited incremental cardiopulmonary exercise testing on a cycle ergometer between 2018 and 2025. The highest 30-s average value from exercise testing defined peak oxygen uptake (VO₂ peak). VO₂ peak were lower in older age groups in both sexes. In men, VO₂ peak values was 43.4 ± 7.41 mL/kg/min during ages 20-29 and 38.3 ± 6.32 mL/kg/min during ages 50-59. In women, corresponding VO₂ peak values were 39.2 ± 6.49 and 30.8 ± 5.78 mL/kg/min. Peak heart rate also was lower in older ages (men: 174 ± 11 to 142 ± 8 bpm; women: 179 ± 10 to 143 ± 11 bpm). Simple linear regression results showed that age was a significant predictor of VO₂ peak, BMI, and peak heart rate in both men and women (p < .001). This study provides the first nationally relevant descriptive data on CRF reference values for Kazakh adults.

Background. Atrial Fibrillation is a prevalent cardiac arrhythmia associated with irregular heartbeats, posing significant health risks. The purpose of the study is literature review seeks to explore the intricate relationship between cardiorespiratory endurance and Atrial Fibrillation, shedding light on how cardiorespiratory parameters can serve as essential markers for assessing physical activity levels. Materials and methods. The search was conducted using electronic databases, particularly PubMed, Google Scholar, and Scopus. Titles and abstracts of identified studies were screened for relevance, and full-text articles were reviewed for eligibility. The following keywords were used in the search: atrial fibrillation, cardiorespiratory fitness, maximal oxygen consumption, cardiovascular mortality. The search depth is 25 years. Results. Physical activity adherence lowers overall and cardiovascular mortality in Atrial Fibrillation patients. Tailored exercise regimens alleviate Atrial Fibrillation symptoms, improve heart rate control, and enhance well-being. Standardizing cardiorespiratory testing protocols is crucial for consistent comparisons. Various testing methods, including treadmill protocols and cycle ergometers, offer insights into Cardiorespiratory fitness. Differences between treadmill and cycle ergometer out-comes warrant careful interpretation. Normative values vary across populations, influenced by physical activity, geography, genetics, and testing modalities. Conclusions. Integrating cardiorespiratory testing into AF management enhances diagnosis and personalized interventions, contributing to a nuanced approach in addressing this prevalent cardiac condition.