Incidence of acute-onset atrial fibrillation correlates with air temperature. Results of a nine-year survey

Exploring the link between blood pressure variability and atrial fibrillation: current insights and future directions

Atrial fibrillation (AF) is the most common heart rhythm disorder, especially in people over the age of 50, which affects more than 40 million people worldwide. Many studies have highlighted the association between hypertension with the development of AF. Blood pressure variability (BPV) is a dynamic size obtained by recording blood pressure oscillations using specific readings and at specific time intervals. A multitude of internal and external factors shape BPV while at the same time constituting a common pathogenetic pathway with the development of AF. Until recently, BPV has been applied exclusively in preclinical and clinical studies, without significant implications in clinical practice. Indeed, even from the research side, the determination of BPV is limited to patients without AF due to doubts about the accuracy of its measurement methods in patients with AF. In this review, we present the current evidence on common pathogenic pathways between BPV and AF, the reliability of quantification of BPV in patients with AF, the prognostic role of BPV in these patients, and discuss the future clinical implications of BPV in patients with AF.

Environmental Exposome and Atrial Fibrillation: Emerging Evidence and Future Directions

There has been increased awareness of the linkage between environmental exposures and cardiovascular health and disease. Atrial fibrillation is the most common sustained cardiac arrhythmia, affecting millions of people worldwide and contributing to substantial morbidity and mortality. Although numerous studies have explored the role of genetic and lifestyle factors in the development and progression of atrial fibrillation, the potential impact of environmental determinants on this prevalent condition has received comparatively less attention. This review aims to provide a comprehensive overview of the current evidence on environmental determinants of atrial fibrillation, encompassing factors such as air pollution, temperature, humidity, and other meteorologic conditions, noise pollution, greenspace, and the social environment. We discuss the existing evidence from epidemiological and mechanistic studies, critically evaluating the strengths and limitations of these investigations and the potential underlying biological mechanisms through which environmental exposures may affect atrial fibrillation risk. Furthermore, we address the potential implications of these findings for public health and clinical practice and identify knowledge gaps and future research directions in this emerging field.

Meteorological Influence on Atrial Fibrillation and Flutter: A Nationwide Observational Study in South Korea (2010-2022)

Background and rationale The impact of meteorological factors, including atmospheric temperature, humidity, and wind speed, on the incidence of atrial fibrillation and flutter (AF) has been the subject of several studies, but the findings have been inconsistent. Given the complex and multifaceted nature of this relationship, a larger-scale study was necessary to provide sufficient statistical power and elucidate potential associations between them. The aim of this study was, thus, to investigate the potential associations between meteorological factors and the incidence of AF. Methods The South Korean government provides open access to national health insurance and weather data for its citizens; the data was available from January 2010 to July 2022. The national health insurance data includes the monthly number of patients diagnosed with a specific condition, reflecting the incidence and prevalence of the condition. Pearson correlation analyses were performed using the statistical analysis software, SAS® OnDemand for Academics (SAS Institute Inc., Cary, North Carolina, United States), to examine the association between each month's national average climate data and the number of patients diagnosed with AF. Results The number of patients diagnosed with AF in the total population showed a statistically significant correlation only with average wind speed (correlation coefficient (r)=-0.42, 95%CI -0.55 to -0.28, p<0.001) and sunshine duration (r=0.27, 95%CI 0.12 to 0.41, p<0.001). Among females aged 20-24 years, there was a statistically significant association with other variables, including average temperature, precipitation, humidity, and atmospheric pressure (p<0.05). Diurnal temperature variation showed inconsistent associations across different age and sex groups. Conclusion The number of patients diagnosed with AF is negatively correlated with average wind speed and positively correlated with sunshine duration in the general population, particularly among the elderly. There was no significant association between the number of patients diagnosed with AF and average temperature, precipitation, or humidity, except for females aged 20-24 years, who exhibited a significant association with these variables. However, it is important to note that these correlations do not establish causality.

Low ambient temperature increases the risk and burden of atrial fibrillation episodes: A nationwide case-crossover study in 322 Chinese cities

BACKGROUND

Non-optimum ambient temperature has recently been acknowledged as an independent risk factor for disease burden, but its impact on atrial fibrillation (AF) episodes was rarely evaluated.

OBJECTIVES

To examine the associations between ambient non-optimum temperature and symptom onset of AF episodes and calculate the corresponding disease burden.

METHODS

We conducted an individual-level, time-stratified, case-crossover analysis based on a nationwide registry, which comprises of 94,711 eligible AF patients from 1993 hospitals in 322 Chinese cities from January 2015 to December 2021. Multiple moving 24 h average temperatures prior to the symptom onset of AF episodes were calculated as lag days. The associations were analyzed using conditional logistic regression combined with distributed lag non-linear models with a duration of lag 0-7 days, after controlling for criteria air pollutants. Stratification analyses were performed to explore possible effect modifiers.

RESULTS

There was a monotonically increasing relationship of AF onset risk with decreasing temperature. The excess AF risk occurred at lag 1 d and lasted for 5 days. Nationally, the cumulative relative risk of AF episode onset associated with extremely low temperature (-9.3 °C) over lag 0-7 d was 1.25 (95 % confidence interval: 1.08, 1.45), compared with the reference temperature (31.5 °C). The exposure-response curve was steeper in the south than in the north where there was levelling-off at lower temperature. Nationally, 7.59 % of acute AF episodes could be attributable to non-optimum temperatures. The attributable fraction was larger for southern residents, males and patients <65 years.

CONCLUSION

This nationwide study provides novel and robust evidence that declining ambient temperature could increase the risk of AF episode onset. We also provide the first-hand evidence that a considerable proportion of acute AF episodes could be attributable to non-optimum temperatures.

Ability to adapt to seasonal temperature extremes among atrial fibrillation patients. A nation-wide study of hospitalizations in Israel

BACKGROUND

In recent years, temperature fluctuations and adverse weather events have become major concerns, influencing overall mortality and morbidity. While the association between extreme temperatures and atrial fibrillation (AF) has been supported by research, there is limited evidence on the ability of AF patients to adapt to the changing temperatures. We explored this question among AF patients in Israel featured by extreme temperature conditions.

METHODS

We examined the association between exposure to extreme temperatures and hospitalizations related to AF in a nationwide cohort in Israel. A case-crossover design with a distributed nonlinear model (DLNM) was applied to assess possible effects of temperature fluctuations during each season. We considered the 7 days prior to the event as the possible window period.

RESULTS

During 2004-2018 we recorded a total of 54,909 hospitalizations for AF. Low temperatures in winter and high in summer adversely affected AF-related hospitalizations. The effect recorded for the first few weeks of each season was of higher magnitude and decreased or faded off completely as the seasons progressed (OR in winter: from 1.14, 95%CI 0.98, 1.32 to 0.90, 95%CI: 0.77, 1.06;OR in summer: from 1.95, 95%CI: 1.51, 2.52 to 1.22, 95%CI: 0.90, 1.65). Patients living in the south region and patients with low socioeconomic status were more susceptible to extreme temperatures.

CONCLUSIONS

Although extreme hot and cold temperatures are associated with an increased risk of hospitalization for AF, the patients are likely to adapt to temperature change over the course of the first weeks of the season.

Epidemiology of Atrial Fibrillation and Related Myocardial Ischemia or Arrhythmia Events in Chinese Community Population in 2019

Background

Atrial fibrillation (AF) is the most common arrhythmia, and the incidence increases rapidly all over the world. The global prevalence of AF (age-adjusted) is 0.60% for men and 0.37% for women and the prevalence of AF in China is 0.65%. It is expected that the number of patients with AF will continue to rise in the future worldwide due to population aging.

Objective

To explore the prevalence of AF in Chinese community population in 2019 and clarify the prevalence of AF complicated with other arrhythmias and myocardial ischemia (MI) events.

Methods

The remote electrocardiogram (ECG) diagnosis system of Xinhua Hospital was assessed to the screen participants with ECG evidence of AF between January 1 and December 31, 2019. The prevalence rates of AF and its association with other arrhythmias and MI events were analyzed and subgroup analysis was performed between different sexes and age groups.

Results

A total of 22,016 AF cases were identified out of all ECGs derived from the remote ECG diagnosis system in 2019. It is estimated that AF was presented in nearly 10.15 million people in China (age-adjusted standardized rate 0.72%, 95% CI 0.20–1.25%) in 2019 and 62% of the AF cases (6.27 million) affected people aged 65 years and above (age-adjusted standardized rate 3.56%, 95% CI 3.28–3.85%). The prevalence rate of AF in males was higher than that in females (p < 0.001), and the ventricular rate of AF patients was faster in females (p < 0.001) and younger patients (p < 0.001). AF patients with lower ventricular rate (under 60 beats per min) were associated with increased prevalence of ventricular escape/escape rhythm [p < 0.001, odds ratio (OR) 5.14] and third-degree atrioventricular block (p < 0.001, OR 32.05).

Conclusion

The prevalence of AF is higher in the Chinese community population than that was previously reported. AF patients complicated with ECG patterns suggesting myocardial infarction is common in men, and stricter measures should be taken to control the common risk factors of AF and coronary heart disease. It is also important that more attention should be paid to recognize fatal arrhythmias, especially in elderly male patients with AF.

Seasonal Variation of Atrial Fibrillation Admission and Quality of Care in the United States

Background Currently, little is known regarding seasonal variation for atrial fibrillation (AF) in the United States and whether quality of care for AF varies between seasons. Methods and Results The GWTG-AFib (Get With The Guidelines-AFib) registry was initiated by the American Heart Association to enhance national guideline adherence for treatment and management of AF. Our analyses included 61 291 patients who were admitted at 141 participating hospitals from 2014 to 2018 across the United States. Outcomes included numbers of AF admissions and quality-of-care measures (defect-free care, defined as a patient's receiving all eligible measures). For quality-of-care measures, generalized estimating equations accounting for within-site correlations were used to estimate odds ratios (ORs) with 95% CIs, adjusting patient and hospital characteristics. The proportion of AF admissions for each season was similar, with the highest percentage of AF admissions being observed in the fall (spring 25%, summer 25%, fall 27%, and winter 24%). Overall, AF admissions across seasons were similar, with no seasonal variation observed. No seasonal variation was observed for incident AF. There were no seasonal differences in care quality (multivariable adjusted ORs and 95% CIs were 0.93 (0.87-1.00) for winter, 1.09 (1.01-1.18) for summer, and 1.08 (0.97-1.20) for fall, compared with spring). Conclusions In a nationwide quality improvement registry, no seasonal variation was observed in hospital admissions for AF or quality of care for AF.

Impact of Extreme Temperatures on Ambulance Dispatches Due to Cardiovascular Causes in North-West Spain

Introduction and objectives. The increase in mortality and hospital admissions associated with high and low temperatures is well established. However, less is known about the influence of extreme ambient temperature conditions on cardiovascular ambulance dispatches. This study seeks to evaluate the effects of minimum and maximum daily temperatures on cardiovascular morbidity in the cities of Vigo and A Coruña in North-West Spain, using emergency medical calls during the period 2005–2017. Methods. For the purposes of analysis, we employed a quasi-Poisson time series regression model, within a distributed non-linear lag model by exposure variable and city. The relative risks of cold- and heat-related calls were estimated for each city and temperature model. Results. A total of 70,537 calls were evaluated, most of which were associated with low maximum and minimum temperatures on cold days in both cities. At maximum temperatures, significant cold-related effects were observed at lags of 3–6 days in Vigo and 5–11 days in A Coruña. At minimum temperatures, cold-related effects registered a similar pattern in both cities, with significant relative risks at lags of 4 to 12 days in A Coruña. Heat-related effects did not display a clearly significant pattern. Conclusions. An increase in cardiovascular morbidity is observed with moderately low temperatures without extremes being required to establish an effect. Public health prevention plans and warning systems should consider including moderate temperature range in the prevention of cardiovascular morbidity.

Meteorological Factors and Air Pollutants Contributing to Seasonal Variation of Acute Exacerbation of Atrial Fibrillation: A Population-Based Study

OBJECTIVE

We investigated seasonal variation of acute exacerbation of atrial fibrillation (AAF) and contributing environmental factors.

METHODS

AAF events, meteorological elements, and air pollutants in Seoul between 2013 and 2015 were obtained from the nationwide database. AAF was defined if a patient visited the emergency room due to any AF-relevant symptoms or signs.

RESULTS

AAF occurred less frequently in summer than in other seasons (6.71 vs 7.25 events/d, P = 0.005). AAF tended to decrease with an increase of air temperature (r = -0.058). Among air pollutants, NO2 was significantly lower in summer and positively correlated with AAF after adjusting for other variables (β = 3.197).

CONCLUSIONS

The rate of AAF events was the lowest in summer; air temperature and NO2 were contributing factors. The weather and environmental conditions should be considered as risk factors of AAF.

Brief Episodes of Newly Developed Intraoperative Atrial Fibrillation Predicts Worse Outcomes in Adult Liver Transplantation

BACKGROUND

Although patients undergoing liver transplantation (LT) are frequently exposed to predisposing factors of atrial fibrillation (AF) such as autonomic imbalance, surgical stress, and elevated catecholamine levels, the occurrence of intraoperative AF (IOAF) has not been fully examined in LT candidates.

METHODS

Data from 1059 patients who underwent adult LT from 2006 to 2010 were analyzed. Among patients with preoperative normal sinus rhythm, the incidence, prognosis, and detailed characteristics of newly developed IOAF were assessed. Their risk factors and clinical implication, including hepatic graft survival and mortality, were also examined.

RESULTS

Thirteen (1.2%) cases of AF newly developed intraoperatively. A higher Model for End-Stage Liver Disease score (adjusted odds ratio, 1.077 [95% confidence interval, 1.015-1.143]; P = .015) and fulminant hepatic failure (adjusted odds ratio, 6.844 [95% CI, 1.944-24.096]; P = .003) were associated with its occurrence. Eight cases of newly developed AF occurred immediately after hepatic graft reperfusion; the other 3 cases occurred during the pre-anhepatic or anhepatic phase. The majority of patients (9 cases) experienced only brief episodes of AF lasting <1 hour. Despite all patients with newly developed AF eventually converting to sinus rhythm within 1 week after surgery, the episode of IOAF was independently associated with mortality (adjusted hazard ratio, 5.097 [95% confidence interval, 2.189-11.868]; P < .001) after adjustment for Model for End-Stage Liver Disease score.

CONCLUSIONS

For LT recipients, even a brief episode of newly developed IOAF seems to be an important prognosticator, regardless of AF duration.

The short-term associations of weather and air pollution with emergency ambulance calls for paroxysmal atrial fibrillation

A circadian variation in the cardiovascular parameters has been detected. It is plausible that the influence of the environment varies during different periods of the day. We investigated the association between daily emergency ambulance calls (EC) for paroxysmal atrial fibrillation (AF) that occurred during the time intervals of 8:00-13:59, 14:00-21:59, and 22:00-7:59, and weather conditions and exposure to CO and PM₁₀. We used Poisson regression to explore the association between the risk of EC for AF and environmental variables, adjusting for seasonal variation. Before noon, the risk was associated with an IQR (0.333 mg/m³) increase in CO at lag 2-6 days above the median (RR = 1.15, P = 0.002); a protective impact of CO on previous day was observed (RR = 0.91, P = 0.018). During 14:00-21:59, a negative effect of air temperature below 1.9 °C (lag 2-3 days) was detected (per 10 °C decrease: RR = 1.17, P = 0.044). At night, the elevated risk was associated with wind speed above the median (lag 2-4 days) (per 1-kt increase: RR = 1.07, P = 0.001) and with PM₁₀ at lag 2-5 days below the median (per IQR (7.31 μg/m³) increase: RR = 1.21, P = 0.002). Individuals over 65 years of age were more sensitive to air pollution, especially at night (CO lag 2-3 days < median, per IQR (0.12 mg/m³) increase: RR = 1.14, P = 0.045; PM₁₀ lag 2-5 days < median, per IQR increase: RR = 1.32, P = 0.001). The associations of air pollution and other environmental variables with acute events may be analyzed depending on the time of the event.

Impact of Ambient Temperature on Incidence of Acute Lower Limb Ischemia

BACKGROUND

This was a retrospective study to explore the possible association between atmospheric temperatures with the occurrence of acute leg ischemia (ALI).

METHODS

A linear regression analysis was performed for a period of 10 years on the impact of ambient temperature on the incidence of ALI. Mean ambient temperature on a daily basis was retrieved electronically from our observatory, and the daily incidence of ALI was retrieved from the Clinical Data Analysis and Reporting (CDAR) system. CDAR system could retrieve clinical data from all 42 public hospitals in our region, which provided almost 90% inpatient care of the population. Daily incidence was defined as total number of emergency admissions from all 42 pubic hospitals due to ALI from 00:00 till 23:59 hr of that day.

RESULTS

For the 10-year period, spanning from January 2005 to December 2014, there were a total of 634 recorded ALI with revascularization, 608 (95.9%) of which underwent emergency femoral embolectomy, 15 (2.4%) underwent thrombolysis, and 11 (1.7%) underwent thrombolysis and embolectomy. ALIs with primary amputation or conservative management were excluded from the study. The average daily incidence of ALI was 0.170. A linear regression model was built using mean ambient temperature as independent variable and incidence of ALI as dependent variables. The line of best fit was drawn through the data points. The daily incidence of ALI could be predicted by ambient temperature (in °C) with the equation: incidence = 0.274-0.004 × temperature (linear regression; r = -0.053, r² = 0.003, F = 10.42, and P = 0.001). In other words, daily incidence was 0.274 at 0°C; and for every 10°C increase, the incidence would drop by 0.040. At 30°C, daily incidence of ALI was 0.154.

CONCLUSIONS

This study showed an association of cold temperature and ALI in our population. Measures to protect the susceptible population from cold temperatures should be considered.

Influence of air temperature variations on incidence of epistaxis

OBJECTIVE

Epistaxis is the most common ear, nose, and throat emergency observed in the emergency department (ED). An increased frequency of this condition has been observed during cooler months, but the results of available studies are controversial. The aim of this study was to investigate the seasonality and association of epistaxis presentations to a large urban ED with variations of air temperature and humidity.

METHODS

This study was a retrospective case series. Information on all the patients who presented for epistaxis in the ED of the Academic Hospital of Parma during the years 2003-2012 and ages ≥ 14 years were retrieved from the hospital data base, excluding those attributable to trauma. The chronologic data of all visits were associated with climate data (air temperature and humidity) by univariate linear regression analysis.

RESULTS

Among the 819,596 ED patients seen throughout the observational period, 5404 were admitted for epistaxis. Of these, 5220 were discharged from the ED, whereas 184 (3.4%) needed hospital admission. A strong seasonality of epistaxis was observed, with a peak during winter. A strong negative correlation was also found between the daily number of epistaxes and the mean daily temperature in the whole population as well as in patient subgroups (those undergoing anticoagulant or antiplatelet therapy, or those with hypertension, inherited bleeding disorders, liver cirrhosis, or advanced malignancy). A weaker correlation was also found between air humidity and epistaxis but only in certain subgroups.

CONCLUSIONS

The results of this study provided a contribution to improve our understanding of the epidemiology of epistaxis and for specific health policies that should also be planned by considering the seasonality of nosebleed.

Impact on human health of climate changes

There is increasing evidence that climate is rapidly changing. These changes, which are mainly driven by the dramatic increase of greenhouse gas emissions from anthropogenic activities, have the potential to affect human health in several ways. These include a global rise in average temperature, an increased frequency of heat waves, of weather events such as hurricanes, cyclones and drought periods, plus an altered distribution of allergens and vector-borne infectious diseases. The cardiopulmonary system and the gastrointestinal tract are particularly vulnerable to the adverse effects of global warming. Moreover, some infectious diseases and their animal vectors are influenced by climate changes, resulting in higher risk of typhus, cholera, malaria, dengue and West Nile virus infection. On the other hand, at mid latitudes warming may reduce the rate of diseases related to cold temperatures (such as pneumonia, bronchitis and arthritis), but these benefits are unlikely to rebalance the risks associated to warming.