Impaired brain activity in patients with persistent atrial fibrillation assessed by near-infrared spectroscopy and its changes after catheter ablation

Revitalizing brain perfusion: Unveiling advancements through rhythm control strategies in atrial fibrillation-A systematic review

Background

Recent evidence suggests an elevated risk of cognitive impairment and dementia in individuals with atrial fibrillation (AF), irrespective of stroke occurrence. AF, known to reduce brain perfusion, particularly through silent cerebral ischemia, underscores the intricate relationship between cardiac and cerebral health. The heart plays a crucial role in supporting normal brain function, and rhythm control, a standard AF treatment, has demonstrated enhancements in brain perfusion. This systematic review aimed to examine published data concerning the influence of rhythm control on brain perfusion in patients with atrial fibrillation.

Methods

A systematic search for relevant studies was carried out in Scopus, PubMed, Cochrane Reviews, ProQuest, and EBSCOhost, spanning from their inception until April 30, 2023. Studies that specifically examined brain perfusion following any form of rhythm control in atrial fibrillation were included in the review.

Results

The review encompassed 10 studies involving 436 participants. Among these, six utilized electrical cardioversion for rhythm control. The majority (8 out of 10) demonstrated that restoring sinus rhythm markedly enhances brain perfusion. In one of the two remaining studies, notable improvement was observed specifically in a region closely linked to cognition. Additionally, both studies reporting data on the Mini-Mental State Examination (MMSE) showed a consistent and significant increase in scores following rhythm control.

Conclusion

Successful rhythm control in AF emerges as a significant contributor to enhanced brain perfusion, suggesting a potential therapeutic avenue for reducing cognitive impairment incidence. However, further validation through larger prospective studies and randomized trials is warranted.

Atrial Fibrillation and Cognitive Disorders

The prevalence of atrial fibrillation among older adults is increasing. Research has indicated that atrial fibrillation is linked to cognitive impairment disorders such as Alzheimer and vascular dementia, as well as Parkinson disease. Various mechanisms are believed to be shared between atrial fibrillation and cognitive impairment disorders. The specific pathologies and mechanisms of different cognitive disorders are still being studied. Potential mechanisms include cerebral hypoperfusion, ischemic or hemorrhagic infarction, and cerebrovascular reactivity to carbon dioxide. Additionally, circulatory biomarkers and certain infectious organisms appear to be involved. This review offers an examination of the overlapping epidemiology between atrial fibrillation and cognitive disorders, explores different cognitive disorders and their connections with this arrhythmia, and discusses trials and guidelines for preventing and treating atrial fibrillation in patients with cognitive disorders. It synthesizes existing knowledge on the management of atrial fibrillation and identifies areas that require further investigation to bridge the gap in understanding the complex relationship between dementia and atrial fibrillation.

Reduced dementia risk in patients with optimized anticoagulation therapy undergoing atrial fibrillation ablation

BACKGROUND

Atrial fibrillation (AF) is associated with the development of dementia, and observational studies have shown that oral anticoagulation and catheter ablation reduce dementia risk. However, such studies did not consistently report on periprocedural anticoagulation and long-term oral anticoagulation coverage, for which reason the separate effect of AF ablation on dementia risk could not be established.

OBJECTIVE

We evaluated the protective effect of AF ablation in a large cohort of patients who received optimized anticoagulation and compared them with patients who were managed medically.

METHODS

We retrospectively included 5912 consecutive patients who underwent first-time catheter ablation for AF between 2008 and 2018 and compared them with 52,681 control individuals from the Swedish Patient Register. Propensity score matching produced 2 cohorts of equal size (n = 3940) with similar baseline characteristics. Dementia diagnosis was identified by International Classification of Diseases codes from the patient register.

RESULTS

Most propensity score-matched patients were taking an oral anticoagulant at the start (94.5%) and end (75.0%) of the study. Mean follow-up was 4.9 ± 2.8 years. Catheter ablation was associated with lower risk for the dementia diagnosis compared with the control group (hazard ratio [HR], 0.44; 95% confidence interval [CI], 0.22-0.86; P = .017). The result was similar when including patients with a stroke diagnosis before inclusion (HR, 0.50; 95% CI, 0.28-0.89; P = .019) and after adjustment for the competing risk of death (HR, 0.41; 95% CI, 0.20-0.86; P = .018).

CONCLUSION

Catheter ablation of AF in patients with optimized oral anticoagulation therapy was associated with a reduction in dementia diagnosis, even after adjustment for potential confounders and for competing risk of death.

Effects of rhythm-control and rate-control strategies on cognitive function and dementia in atrial fibrillation: a systematic review and meta-analysis

BACKGROUND

Growing evidence suggests that atrial fibrillation (AF) is an independent risk factor for cognitive impairment and dementia, even in the absence of thromboembolic events and stroke. Whether rhythm-control therapy can protect cognitive function remains unclear. We aimed to evaluate the efficacy of rhythm-control strategies in patients with AF regarding cognitive function and dementia risk.

METHODS

We systematically searched the PubMed, Embase and Cochrane Library databases for randomised clinical trials, cohort and case-control studies evaluating the associations between rhythm-control strategies and cognitive function outcomes up to May 2023. We assessed the risk of bias using the ROBINS-I and the Cochrane risk-of-bias tool. Both fixed- and random-effects models were used to create summary estimates of risk.

RESULTS

We included a total of 14 studies involving 193,830 AF patients. In the pooled analysis, compared with rate-control, rhythm-control therapy was significantly associated with a lower risk of future dementia (hazard ratio (HR) 0.74; 95% confidence interval (CI) 0.62-0.89; I2 = 62%). Among the rhythm-control strategies, AF ablation is a promising treatment that was related to significantly lower risks of overall dementia (HR 0.62; 95% CI 0.56-0.68; I2 = 42%), Alzheimer's disease (HR 0.78; 95% CI 0.66-0.92; I2 = 0%) and vascular dementia (HR 0.58; 95% CI 0.42-0.80; I2 = 31%). Pooled results also showed that compared with patients without ablation, those who underwent AF ablation had significantly greater improvement in cognitive score (standardized mean difference (SMD) 0.85; 95% CI 0.30-1.40; P = 0.005; I2 = 76%).

CONCLUSIONS

Rhythm-control strategies, especially ablation, are effective in protecting cognitive function, reducing dementia risk and thus improving quality of life in AF patients.

Is catheter ablation associated with preservation of cognitive function? An analysis from the SAGE-AF observational cohort study

Objectives

To examine the associations between catheter ablation treatment (CA) vs. medical management and cognitive impairment among older adults with atrial fibrillation (AF).

Methods

Ambulatory patients who had AF, were ≥65-years-old, and were eligible to receive oral anticoagulation could be enrolled into the SAGE (Systematic Assessment of Geriatric Elements)-AF study from internal medicine and cardiology clinics in Massachusetts and Georgia between 2016 and 2018. Cognitive function was assessed using the Montreal Cognitive Assessment (MoCA) tool at baseline, 1-, and 2 years. Cognitive impairment was defined as a MoCA score ≤ 23. Multivariate-adjusted logistic regression of longitudinal repeated measures was used to examine associations between treatment with CA vs. medical management and cognitive impairment.

Results

887 participants were included in this analysis. On average, participants were 75.2 ± 6.7 years old, 48.6% women, and 87.4% white non-Hispanic. 193 (21.8%) participants received a CA before enrollment. Participants who had previously undergone CA were significantly less likely to be cognitively impaired during the 2-year study period (aOR 0.70, 95% CI 0.50-0.97) than those medically managed (i.e., rate and/or rhythm control), even after adjusting with propensity score for CA. At the 2-year follow-up a significantly greater number of individuals in the non-CA group were cognitively impaired (MoCA ≤ 23) compared to the CA-group (311 [44.8%] vs. 58 [30.1%], p = 0.0002).

Conclusion

In this 2-year longitudinal prospective cohort study participants who underwent CA for AF before enrollment were less likely to have cognitive impairment than those who had not undergone CA.

Association Between Catheter Ablation and Dementia Among Patients With Atrial Fibrillation: A Systematic Review and Meta-analysis

Atrial fibrillation (AF) is associated with an increased risk of Dementia. However, the association between catheter ablation (CA) in patients with atrial fibrillation and the risk of dementia is not well established, with conflicting results to date. We aimed to evaluate the association between CA patients and the risk of Dementia. We performed a systematic literature search using the PubMed, Embase, Scopus, and Cochrane libraries for relevant articles from inception until 10th May 2023. Hazard ratios (HR) were pooled using a random-effect model, and a P-value of < 0.05 was considered statistically significant. A total of 5 studies with 125,649 patients (30,192 in the CA group and 95,457 in the non-CA group) were included. The mean age of patients among CA and non-CA groups was comparable (58.7 vs 58.18). The most common comorbidity among CA and non-CA groups was hypertension (18.49% vs 81.51%), respectively. Pooled analysis of primary outcome showed that CA was associated with a significant reduction in the risk of Dementia (HR, 0.63 [95% CI: 0.52-0.77], P < 0.001). Similarly, pooled analysis of secondary outcomes showed that the patients with CA had a lower risk of Alzheimer's disease (HR, 0.78 [95% CI: 0.66-0.92], P < 0.001) compared with the non-CA group. However, there was no statistically significant difference in the risk of vascular dementia (HR, 0.63 [95% CI: 0.38-1.06], P = 0.08) between both groups of patients. Our study suggested that catheter ablation reduced the risk of dementia and Alzheimer's disease compared to the nonablation group of patients.

Is Catheter Ablation Associated with Preservation of Cognitive Function? An Analysis From the SAGE-AF Observational Cohort Study

Objectives

To examine the associations between catheter ablation treatment (CA) versus medical management and cognitive impairment among older adults with atrial fibrillation (AF).

Methods

Ambulatory patients who had AF, were ≥ 65-years-old, and were eligible to receive oral anticoagulation could be enrolled into the SAGE (Systematic Assessment of Geriatric Elements)-AF study from internal medicine and cardiology clinics in Massachusetts and Georgia between 2016 and 2018. Cognitive function was assessed using the Montreal Cognitive Assessment (MoCA) tool at baseline, one-, and two years. Cognitive impairment was defined as a MoCA score ≤ 23. Multivariate-adjusted logistic regression of longitudinal repeated measures was used to examine associations between treatment with CA vs. medical management and cognitive impairment.

Results

887 participants were included in this analysis. On average, participants were 75.2 ± 6.7 years old, 48.6% women, and 87.4% white non-Hispanic. 193 (21.8%) participants received a CA before enrollment. Participants who had previously undergone CA were significantly less likely to be cognitively impaired during the two-year study period (aOR 0.70, 95% CI 0.50-0.97) than those medically managed (i.e., rate and/or rhythm control), even after adjusting with propensity score for CA. At the two-year follow-up a significantly greater number of individuals in the non-CA group were cognitively impaired (MoCA ≤ 23) compared to the CA-group (311 [44.8%] vs. 58 [30.1%], p=0.0002).

Conclusions

In this two-year longitudinal prospective cohort study participants who underwent CA for AF before enrollment were less likely to have cognitive impairment than those who had not undergone CA.

Improvement in cerebral oxygen saturation with sinus conversion during off pump coronary artery bypass graft: A case report

RATIONALE

Near-infrared spectroscopy (NIRS) is a noninvasive bedside tool for monitoring regional cerebral oxygen saturation (rSO2). The sinus conversion of atrial fibrillation (AF) was shown to be responsible for increasing rSO2. However, the reason for this improvement has not yet been clearly explained.

PATIENT CONCERNS

We report the case of a 73-year-old woman who underwent cardioversion during an off-pump coronary artery bypass under NIRS and live hemodynamic monitoring.

INTERVENTIONS

Unlike previous studies that failed to control and compare all conditions during procedures, this case showed real-time fluctuating hemodynamic and hematological values, such as hemoglobin (Hgb), central venous pressure (CVP), mean arterial pressure (MAP), cardiac index (CI), left ventricular end-diastolic pressure (LVEDP), and SVO2.

OUTCOMES

The rSO2 increased immediately after cardioversion and decreased during the obtuse marginal (OM) graft and after AF was obtained. However, no other hemodynamic data showed the same or opposite directional changes in the rSO2.

LESSONS

Significant instantaneous changes were observed in rSO2 using NIRS after sinus conversion, without obvious hemodynamic alterations in the systemic circulation or other monitoring values.

Ablation of atrial fibrillation and dementia risk reduction during long-term follow-up: a nationwide population-based study

AIMS

This study investigated the epidemiological characteristics of new-onset dementia in patients with atrial fibrillation (AF) and the association of catheter ablation with different subtypes of dementia.

METHODS AND RESULTS

We conducted a population-based, retrospective cohort study using data from the Taiwan National Health Insurance Research Database. In total, 136 774 patients without a history of dementia were selected after 1:1 propensity score matching based on age (with AF vs. without AF). A competing risk model was used to investigate the three subtypes of dementia: Alzheimer's disease, vascular dementia, and other/mixed dementia. Inverse probability of treatment weighting (IPTW) was performed to minimize the impact on dementia risk due to the imbalanced baseline characteristics. After a median follow-up period of 6.6 years, 8704 events of new-onset dementia occurred. Among all AF patients developing dementia, 73% were classified as having Alzheimer's disease, 16% as having vascular dementia, and 11% as having other/mixed dementia. The cumulative incidence of dementia in AF patients was higher than those without AF (log-rank test: P < 0.001 for both before and after IPTW). In patients with AF undergoing catheter ablation, the total dementia risk decreased significantly [P = 0.015, hazard ratio (HR): 0.74, 95% confidence interval (CI): 0.58-0.94] after multivariable adjustment, but not for the subtype of vascular dementia (P = 0.59, HR: 0.86, 95% CI: 0.49-1.50).

CONCLUSION

Patients with AF have a higher incidence of all types of dementia, including Alzheimer's disease, vascular dementia, and a mixed type of dementia. Alzheimer's disease is less likely to occur in patients with AF undergoing catheter ablation.

The Impact of Atrial Fibrillation Treatment Strategies on Cognitive Function

There is increasing evidence to suggest that atrial fibrillation is associated with a heightened risk of dementia. The mechanism of interaction is unclear. Atrial fibrillation-induced cerebral infarcts, hypoperfusion, systemic inflammation, and anticoagulant therapy-induced cerebral microbleeds, have been proposed to explain the link between these conditions. An understanding of the pathogenesis of atrial fibrillation-associated cognitive decline may enable the development of treatment strategies targeted towards the prevention of dementia in atrial fibrillation patients. The aim of this review is to explore the impact that existing atrial fibrillation treatment strategies may have on cognition and the putative mechanisms linking the two conditions. This review examines how components of the 'Atrial Fibrillation Better Care pathway' (stroke risk reduction, rhythm control, rate control, and risk factor management) may influence the trajectory of atrial fibrillation-associated cognitive decline. The requirements for further prospective studies to understand the mechanistic link between atrial fibrillation and dementia and to develop treatment strategies targeted towards the prevention of atrial fibrillation-associated cognitive decline, are highlighted.

Association of Electrical Cardioversion with Brain Perfusion and Cognitive Function in Patients with Atrial Fibrillation

Background: The association of atrial fibrillation (AF) and brain perfusion (BP) has not been well-defined. This study aimed to determine the association of persistent AF with BP and cognition, in comparison to control subjects and with regards to electrical cardioversion (ECV). Methods: This study compared 25 patients with persistent AF undergoing elective ECV with 16 age/sex-matched controls. We measured regional BP by using the magnetic resonance (MRI) arterial spin labelling technique. Cognitive function was assessed using the Patient-Reported Outcomes Measurement Information System (PROMIS) cognitive function index. Measurements were performed at baseline and 6 weeks after ECV. Results: There was no significant difference in BP between AF patients and control subjects (p > 0.05). Following the ECV, there was a significant improvement in BP in 15 patients who maintained sinus rhythm, while there was no significant change in the recurrence group (297 ± 24 before vs. 328 ± 37 after ECV, p = 0.008, and 297 ± 22 before vs. 307 ± 24 after ECV, p = 0.45, respectively). There was no difference in the cognitive assessment between AF patients and control subjects, as well as before and after ECV within the AF group (52.2 ± 9.6 vs. 51.2 ± 6.2, p = 0.71 and 53 ± 10 vs. 54 ± 9, p = 0.46, respectively). Conclusions: This study did not show difference in BP between persistent AF patients and matched control subjects. Restoration of sinus rhythm was associated with significantly improved BP. There was no association of ECV and changes in cognitive function.

This is Your Brain, and This is Your Brain on Atrial Fibrillation: The Roles of Cardiac Malperfusion Events and Vascular Dysfunction in Cognitive Impairment

AF is an independent and strong predictor of long-term cognitive decline. However, the mechanism for this cognitive decline is difficult to define and likely multifactorial, leading to many different hypotheses. Examples include macro- or microvascular stroke events, biochemical changes to the blood-brain barrier related to anticoagulation, or hypo-hyperperfusion events. This review explores and discusses the hypothesis that AF contributes to cognitive decline and dementia through hypo-hyperperfusion events occurring during cardiac arrhythmias. We briefly explain several brain perfusion imaging techniques and further examine the novel findings associated with changes in brain perfusion in patients with AF. Finally, we discuss the implications and areas requiring more research to further understand and treat patients with cognitive decline related to AF.