Physical activity, height, and left atrial size are independent risk factors for lone atrial fibrillation in middle-aged healthy individuals

Previous Exercise Levels and Outcome in Patients with New Atrial Fibrillation: "Past Achievements Do Not Predict the Future"

INTRODUCTION

Long-term endurance exercise is suspect to elevate the risk of atrial fibrillation (AF), but little is known about cardiovascular outcome and disease progression in this subgroup of AF patients. We investigated whether previous exercise level determines cardiovascular outcome.

METHODS

In this post hoc analysis of the RACE 4 randomized trial, we analyzed all patients with a completed questionnaire on sports participation. Three subgroups were made based on lifetime sports hours up to randomization and previous compliance to the international physical activity guidelines. High lifetime hours of high dynamic activity patients were defined as more than 150 min·wk -1 of high-intensity physical exercise. The primary endpoint was a composite of cardiovascular death and hospital admissions.

RESULTS

A total of 879 patients were analyzed, divided in 203 high lifetime hours of high dynamic activity, 192 high lifetime hours of activity, and 484 low lifetime hours of activity patients. Over a mean follow-up of 36 months (±14), the primary endpoint occurred in 61 out of 203 (30%) high lifetime hours of high dynamic activity, 53 out of 192 (27%) high lifetime hours of activity, and 135 out of 484 (28%) low lifetime hours of activity patients ( P = 0.74). During follow-up, 42 high lifetime hours of high dynamic activity (35%), 43 high lifetime hours of activity (32%), and 104 low lifetime hours of activity patients (34%) with paroxysmal AF received electrical or chemical cardioversion or atrial ablation ( P = 0.90).

CONCLUSIONS

In patients included in the RACE 4, there seems to be no relation between previous activity levels and cardiovascular outcome and the need for electrical or chemical cardioversion or atrial ablation. Cardiovascular outcome was driven by AF-related arrhythmic events.

Sodium Intake and Incident Atrial Fibrillation in Individuals With Vascular Disease

Importance

Numerous prospective cohort studies have reported a J-shaped association of urinary sodium excretion with cardiovascular events and mortality.

Objective

To study the association between sodium intake and incident atrial fibrillation (AF).

Design, Setting, and Participants

This cohort study included participants in the Ongoing Telmisartan Alone and in Combination with Ramipril Global Endpoint Trial (ONTARGET) and Telmisartan Randomised Assessment Study in ACE Intolerant Subjects With Cardiovascular Disease (TRANSCEND) multicenter, randomized clinical trials comparing the effect of ramipril 10 mg daily with telmisartan 80 mg daily, or their combination (ONTARGET) or 80 mg telmisartan daily with placebo (TRANSCEND) for the outcome of death from cardiovascular causes, myocardial infarction, stroke, or hospitalization for heart failure. ONTARGET and TRANSCEND included 31 546 participants with vascular disease or high-risk diabetes, and this study excluded participants without a urine sample for sodium measurement, missing data for key covariates, a history of AF, or AF detected in the first year after enrollment. Analyses were performed in July 2023 to May 2024.

Exposure

Estimated sodium intake from a morning fasting urine sample (Kawasaki formula).

Main Outcomes and Measures

The main outcome was incident AF. The association between estimated sodium intake and incident AF was modeled using multivariable adjusted Cox regression and cubic splines.

Results

A total of 27 391 participants (mean [SD] age, 66.3 [7.2] years; 19 310 [70.5%] male) were included. Mean (SD) estimated sodium intake was 4.8 (1.6) g/d. During a mean (SD) follow-up of 4.6 (1.0) years, 1562 participants (5.7%) had incident AF. After multivariable adjustment, a J-shaped association between sodium intake and AF risk was observed (P for nonlinearity = .03). Sodium intake of 8 g/d or greater (3% of participants) was associated with incident AF (hazard ratio, 1.32; 95% CI, 1.01-1.74) compared with sodium intake of 4 to 5.99 g/d. Cubic splines showed that sodium intake greater than 6 g/d (19% of participants) was associated with a 10% increased AF risk per additional 1-g/d sodium intake (hazard ratio, 1.10; 95% CI, 1.03-1.18), but with no further lowering of AF risk at lower levels of sodium intake.

Conclusions and Relevance

In this cohort study of sodium intake and AF risk, there was a J-shaped association between sodium intakes and AF risk in patients with cardiovascular disease or diabetes. Lowering sodium intake for AF prevention is best targeted at individuals who consume high sodium diets.

Associations between postrace atrial fibrillation and measures of performance, racing history and airway disease in horses

BACKGROUND

Atrial fibrillation (AF) is the most common performance limiting arrhythmia in racehorses. High dose exercise and airway disease promote AF in humans. Few studies have investigated epidemiological factors associated with AF in horses.

OBJECTIVES

Explore variables relating to performance, exercise volume and postrace endoscopic findings in horses with AF.

ANIMALS

A total of 164 horses with poor race performance and postrace AF were compared to 321 horses with poor performance without AF (PP) and 314 horses performing to expectation (TE).

METHODS

Horse-level and race-level variables for horses racing in Australia and Hong Kong from 2009 to 2021 were compared using univariable and multivariable logistic regression. Postrace endoscopic exercise-induced pulmonary hemorrhage (EIPH) and tracheal mucus accumulation (TMA) grades for AF and PP horses were compared using chi-squared analysis.

RESULTS

Variables that were significant in the multivariable model of AF compared to TE were distance (lengths) behind the winner, (odds ratio [OR]; 95% confidence interval [95% CI], 1.41 [1.32-1.51], P < .0001), cumulative prize money per start before the event (OR [95% CI] 1.02 [1.01-1.03], P = .01) and age (OR [95% CI] 0.72 [0.55-0.92], P = .01). More AF horses had EIPH grade ≥ 3 (23/109; 21.1%) than PP horses (7/213; 3.3%; OR [95%CI] 7.9 [3.3-20.2], P < .0001).

CONCLUSIONS AND CLINICAL IMPORTANCE

Acute race performance was substantially impaired by AF but career earnings before the event were not inferior. Exercise volume did not promote AF. Higher grades of EIPH found in AF horses suggests a mechanistic relationship between these conditions.

Markers of Atrial Myopathy in the General Population: Prevalence, Predictors, and Inter-Relations

BACKGROUND

Atrial myopathy refers to structural and functional cardiac abnormalities associated with atrial fibrillation and stroke, but appropriate diagnostic criteria are lacking.

OBJECTIVES

This study aimed to assess prevalence, clinical correlates, and overlap between potential atrial myopathy markers.

METHODS

The population-based SCAPIS (Swedish CArdioPulmonary bioImage Study) prospectively included 6,013 subjects without atrial fibrillation with 24-hour electrocardiograms. Resting electrocardiograms measuring P-wave indices were collected at 1 screening site (n = 1,201), and a random sample (n = 385) had echocardiographic left atrial volume index (LAVi). Atrial myopathy markers were defined as ≥500 premature atrial complexes/24 h, LAVi ≥34 mL/m2, P-wave duration >120 milliseconds, or P-wave terminal force in V1 >4,000 ms·s. Clinical correlates included age, sex, body mass index, height, smoking, physical activity, coronary artery disease, diabetes, systolic blood pressure, antihypertensive medication, and low education.

RESULTS

Atrial myopathy was common; 42% of the sample with all diagnostic modalities available had ≥1 atrial myopathy marker, but only 9% had 2 and 0.3% had ≥3. Only P-wave duration and LAVi were correlated (ρ = 0.10; P = 0.04). Clinical correlates of premature atrial complexes, P-wave indices, and LAVi differed; current smoking (34% increase; P < 0.001), systolic blood pressure (4%/mm Hg increase; P = 0.01), diabetes (35% increase; P = 0.001), and coronary artery disease (71% increase; P = 0.003) were associated with premature atrial complexes, physical activity ≥2 h/wk was associated with increased LAVi (β-coefficient = 3.1; P < 0.0001) and body mass index was associated with P-wave duration (β-coefficient = 0.4/kg/m2; P < 0.0001).

CONCLUSIONS

In the general population, indirect markers of atrial myopathy are common but only weakly correlated, and their risk factor patterns are different. More studies are needed to accurately identify individuals with atrial myopathy with diagnostic methods.

Predictors of Atrial Fibrillation in Patients with Embolic Stroke of Unknown Etiology and Implantable Loop Recorders-Further Insights of the TRACK AF Study on the Role of ECG and Echocardiography

Aims-Electrocardiography (ECG) and echocardiographic left atrial (LA) parameters may be helpful to assess the risk of atrial fibrillation (AF) in embolic stroke of unknown etiology (ESUS) and could therefore guide intensity of ECG monitoring. Methods-1153 consecutive patients with ischemic stroke or transient ischemic attack (TIA) were analyzed. An internal loop recorder (ILR) was implanted in 104 consecutive patients with ESUS. Multiple morphologic P-wave parameters in baseline 12-channel ECG and echocardiographic LA parameters were measured and analyzed in patients with and without ILR-detected AF. Using logistic regression, we evaluated the predictive value of several ECG parameters and LA dimensions on the occurrence of AF. Results-In 20 of 104 (19%) patients, AF was diagnosed by ILR during a mean monitoring time of 575 (IQR 470-580) days. Patients with AF were significantly older (72 (67-75) vs. 60 (52-72) years; p = 0.001) and premature atrial contractions (PAC) were more frequently observed (40% vs. 2%; p < 0.001) during baseline ECG. All morphologic P-wave parameters did not show a significant difference between groups. There was a non-significant trend towards a larger LA volume index (31 (24-36) vs. 29 (25-37) mL/m2; p = 0.09) in AF patients. Conclusions-Age and PAC are independently associated with incident AF in ESUS and could be used as markers for selecting patients that may benefit from more extensive rhythm monitoring or ILR implantation. In our consecutive cohort of patients with ESUS, neither morphological P-wave parameters nor LA size were predictive of AF.

Multiple anthropometric measures and proarrhythmic 12-lead ECG indices: A mendelian randomization study

BACKGROUND

Observational studies suggest that electrocardiogram (ECG) indices might be influenced by obesity and other anthropometric measures, though it is difficult to infer causal relationships based on observational data due to risk of residual confounding. We utilized mendelian randomization (MR) to explore causal relevance of multiple anthropometric measures on P-wave duration (PWD), PR interval, QRS duration, and corrected QT interval (QTc).

METHODS AND FINDINGS

Uncorrelated (r2 < 0.001) genome-wide significant (p < 5 × 10-8) single nucleotide polymorphisms (SNPs) were extracted from genome-wide association studies (GWAS) on body mass index (BMI, n = 806,834), waist:hip ratio adjusted for BMI (aWHR, n = 697,734), height (n = 709,594), weight (n = 360,116), fat mass (n = 354,224), and fat-free mass (n = 354,808). Genetic association estimates for the outcomes were extracted from GWAS on PR interval and QRS duration (n = 180,574), PWD (n = 44,456), and QTc (n = 84,630). Data source GWAS studies were performed between 2018 and 2022 in predominantly European ancestry individuals. Inverse-variance weighted MR was used for primary analysis; weighted median MR and MR-Egger were used as sensitivity analyses. Higher genetically predicted BMI was associated with longer PWD (β 5.58; 95%CI [3.66,7.50]; p = < 0.001), as was higher fat mass (β 6.62; 95%CI [4.63,8.62]; p < 0.001), fat-free mass (β 9.16; 95%CI [6.85,11.47]; p < 0.001) height (β 4.23; 95%CI [3.16, 5.31]; p < 0.001), and weight (β 8.08; 95%CI [6.19,9.96]; p < 0.001). Finally, genetically predicted BMI was associated with longer QTc (β 3.53; 95%CI [2.63,4.43]; p < 0.001), driven by both fat mass (β 3.65; 95%CI [2.73,4.57]; p < 0.001) and fat-free mass (β 2.08; 95%CI [0.85,3.31]; p = 0.001). Additionally, genetically predicted height (β 0.98; 95%CI [0.46,1.50]; p < 0.001), weight (β 3.45; 95%CI [2.54,4.36]; p < 0.001), and aWHR (β 1.92; 95%CI [0.87,2.97]; p = < 0.001) were all associated with longer QTc. The key limitation is that due to insufficient power, we were not able to explore whether a single anthropometric measure is the primary driver of the associations observed.

CONCLUSIONS

The results of this study support a causal role of BMI on multiple ECG indices that have previously been associated with atrial and ventricular arrhythmic risk. Importantly, the results identify a role of both fat mass, fat-free mass, and height in this association.

Assessment of P Wave Indices in Healthy Standardbred Horses

P wave indices are used as non-invasive electrocardiographic markers of atrial remodelling in humans. Few studies have investigated their use in animals. The aim of this study was to measure P wave duration and P wave dispersion (Pd) in healthy standardbred horses and investigate variables that might influence these measurements. A 12-lead electrocardiogram was recorded at rest and P wave indices were calculated in 53 horses. A general linear model was used to investigate the main effects: age, bodyweight, sex, resting heart rate, presence of a murmur, exercise status and the number of years raced. There were significant associations with exercise status for both the maximum P wave duration and Pd, with both values being increased in strenuously exercising versus non-active horses. Furthermore, a significant moderate positive correlation was identified between the duration of exercise (number of years raced) and both Pmax and Pd. No other significant associations were identified. These findings are similar to those reported in elite human athletes versus sedentary individuals. The increases in these P wave indices most likely occur due to prolongation and heterogeneity in atrial conduction time, which are associated with structural and electrical remodelling, and may explain the increased risk of atrial fibrillation in athletic horses.

The prognostic predictive value of the components of the PR interval in hospitalized patients with heart failure

OBJECTIVE

Previous reports on the epidemiology, influencing factors, and the prognostic value of the components of PR interval in hospitalized heart failure patients were limited.

METHODS

This study retrospectively enrolled 1182 patients hospitalized with heart failure from 2014 to 2017. Multiple linear regression analysis was used to explore the association between the components of PR interval and the baseline parameters. The primary outcome was all-cause death or heart transplantation. Multivariable-adjusted Cox proportional hazard regression models were constructed to explore the predictive value of the components of PR interval for the primary outcome.

RESULTS

In multiple linear regression analysis, higher height (for every 10 cm increase in height: regression coefficient 4.83, P < 0.001) as well as larger atrial and ventricular size were associated with larger P wave duration but not with PR segment. The primary outcome occurred in 310 patients after an average follow-up of 2.39 years. Cox regression analyses revealed that the increase in PR segment was an independent predictor of the primary outcome (every 10 ms increase: hazard ratio 1.041, 95% confidence interval [CI] 1.010-1.083, P = 0.023), whereas the P wave duration did not show significant correlation. When adding the PR segment to an initial prognostic prediction model, the likelihood ratio test and categorical net reclassification index (NRI) showed a significant improvement, but the increase in C-index was not significant. In subgroup analysis, increased PR segment was an independent predictor of the primary endpoint in patients taller than 170 cm (each 10 ms increase: hazard ratio 1.153, 95% CI 1.085-1.225, P < 0.001) but not the shorter group (P for interaction = 0.006).

CONCLUSIONS

In hospitalized patients with heart failure, longer PR segment was an independent predictor of the composite endpoint of all-cause death and heart transplantation, especially in the taller group, but it had limited significance in improving the prognostic risk stratification of this population.

The association between the body height and cardiovascular diseases: a retrospective analysis of 657,310 outpatients in Germany

Background

Cardiovascular disease (CVD) represents the leading cause of death worldwide. The identification of individuals at increased risk of CVD is essential to reduce its morbidity and mortality globally. Based on existing data on a potential association between the individual body height and the risk for CVD, we investigated this association in a large cohort of outpatients in Germany.

Methods

A total of 657,310 adult outpatients with available body height data from the Disease Analyzer (IQVIA) database were included in Germany between 2019 and 2021. The prevalence of common CVD diagnoses (hypertension, coronary heart disease, atrial fibrillation and flutter, heart failure, ischemic stroke, and venous thromboembolism) was evaluated as a function of the patients’ body height stratified by age and sex.

Results

In both sexes, the prevalence of hypertension, coronary heart disease, heart failure, and ischemic stroke was higher among patients of smaller body height. In contrast, the prevalence of atrial fibrillation and venous thromboembolism was higher in taller patients. In age- and BMI-adjusted logistic regression analyses, an increased body height was negatively associated with coronary heart disease (OR = 0.91 in women and OR = 0.87 in men per 10-cm increase in height) and strongly positively associated with atrial fibrillation (OR = 1.25 in women and men) and venous thromboembolism (OR = 1.23 in women and OR = 1.24 in men).

Conclusion

We present the first data from a large cohort of outpatients in Germany providing strong evidence for an association between the body height and common CVD. These data should stimulate a discussion as to how far the body height should be implemented as a parameter in stratification tools to assess CVD risk in order to further reduce cardiovascular morbidity and mortality in the future.

How synergy between mechanistic and statistical models is impacting research in atrial fibrillation

Atrial fibrillation (AF) with multiple complications, high morbidity and mortality, and low cure rates, has become a global public health problem. Although significant progress has been made in the treatment methods represented by anti-AF drugs and radiofrequency ablation, the therapeutic effect is not as good as expected. The reason is mainly because of our lack of understanding of AF mechanisms. This field has benefited from mechanistic and (or) statistical methodologies. Recent renewed interest in digital twin techniques by synergizing between mechanistic and statistical models has opened new frontiers in AF analysis. In the review, we briefly present findings that gave rise to the AF pathophysiology and current therapeutic modalities. We then summarize the achievements of digital twin technologies in three aspects: understanding AF mechanisms, screening anti-AF drugs and optimizing ablation strategies. Finally, we discuss the challenges that hinder the clinical application of the digital twin heart. With the rapid progress in data reuse and sharing, we expect their application to realize the transition from AF description to response prediction.

U-Shaped Association Between Blood Pressure and Mortality Risk in ICU Patients With Atrial Fibrillation: The MIMIC-III Database

Background

Existing evidence on the association between blood pressure (BP) and mortality risk in intensive care unit (ICU) patients with atrial fibrillation (AF) is scarce.

Aim

This study aimed to assess the associations between blood pressure (BP) and risks of in-hospital and all-cause mortality in ICU patients with AF.

Methods

A total of 2,345 records of patients with AF whose BP was monitored after admission to the ICU were obtained from the MIMIC-III database. Incidences were calculated for endpoints (hospital mortality, 7-day mortality, 30-day mortality, and 1-year mortality). We performed smooth curve and logistic regression analyses to evaluate the association between BP and the risk of each endpoint.

Results

Smooth curve regression showed that systolic blood pressure (SBP), mean arterial pressure (MBP), and diastolic blood pressure (DBP) followed U-shaped curves with respect to endpoints (hospital mortality, 7-day mortality, 30-day mortality, and 1-year mortality). The incidence of these endpoints was lowest at 110/70/55 mm Hg. There was an increased risk of 1-year mortality observed with BP > 110/70/55 mm Hg (SBP, odds ratio [OR] = 1.008, 95% CI 1.001–1.015, p = 0.0022; MBP, OR = 1.010, 95% CI 1.005–1.016, p < 0.001) after adjusting for age, sex, and medical history. In contrast, an inverse association between BP and the risk of 1-year mortality was observed with BP ≤ 110/70/55 mm Hg (SBP, OR = 0.981, 95% CI 0.974–0.988, p < 0.001; MBP OR = 0.959, 95% CI 0.939–0.979, p < 0.001; and DBP, OR = 0.970, 95% CI 0.957–0.983, p < 0.001).

Conclusions

We observed a U-shaped association between BP and in-hospital/all-cause mortality in ICU patients with AF. However, the underlying causes need to be investigated.

Etiology and Outcome of Catheter Ablation in Patients With Onset of Atrial Fibrillation <45 Years of Age

Etiologic factors and long-term outcomes of catheter ablation of atrial fibrillation (AF) in young patients have not been well characterized. This study aimed to analyze the etiologic factors and outcomes of pulmonary vein isolation (PVI) in patients with young-onset AF (young-AF, defined as having first documented episode <45 years). Consecutive patients with young-AF undergoing PVI (n = 197) in 2 academic centers were enrolled and followed for 36.1 ± 24.5 months. A control group of patients with AF onset ≥45 years (n = 554) was included. The most frequent risk factors in young-AF were intensive exercise (25%), moderate-to-heavy alcohol consumption (23%), and familial AF (22%). Compared with patients with AF onset ≥45-year, patients with young-AF were more often men (82% vs 66%, p <0.001), had more frequently paroxysmal AF (81% vs 60%, p <0.001), had less left atrial dilatation (40.9 ± 6.2 mm vs 44.2 ± 7.2 mm, p <0.001), and had lower 4-year recurrence rate after last PVI procedure (22% vs 45%, p <0.001). In young-AF, structural heart disease (SHD) was the only independent predictor of recurrence. Patients with young-AF selected to undergo cryoballoon (CB) ablation were younger (35.0 ± 7.7 vs 36.6 ± 6.7 years, p = 0.035) and had less persistent AF (6% vs 24%, p = 0.004) and coronary artery disease (2% vs 7%, p = 0.02) compared with radiofrequency ablation. After excluding patients with persistent AF and SHD, there was no difference in single procedural success between radiofrequency or CB PVI (27% vs 17%, p = 0.11). In conclusion, patients with young-AF have diverse etiologies and high single and multiprocedural PVI successes. SHD is the only independent predictor of recurrence. In patients with young-AF, there is a selection bias for CB ablation.

Associations between physical activity, left atrial size and incident atrial fibrillation: the Tromsø Study 1994-2016

AIMS

Left atrial (LA) enlargement is an independent risk factor for atrial fibrillation (AF). Interestingly, some athletes have increased risk of AF, which may be linked to LA enlargement; however, little is known about the relationship between LA enlargement and AF risk at moderate-level physical activity (PA). We aimed to explore the associations between PA, LA size and risk of incident AF, and if PA can attenuate the risk of AF with LA enlargement.

METHODS

This prospective study followed 2479 participants (52.4% female), free from known cardiac pathology, for median 20.2 years. Participants were followed up for hospital-diagnosed AF, confirmed by electrocardiography, from 1994-95 through 2016. At baseline, LA size was evaluated by anteroposterior LA diameter, and PA was self-reported by questionnaire.

RESULTS

We observed a U-shaped relationship between PA and AF, and moderately active had 32% lower AF risk than inactive (HRadjusted 0.68, 95% CI 0.50 to 0.93). Participants with LA enlargement had 38% higher AF risk compared with participants with normal LA size (HRadjusted 1.38, 95% CI 1.12 to 1.69). However, the increased AF risk with LA enlargement was attenuated by PA; compared with inactive participants with LA enlargement, the AF risk was 45% lower among active with LA enlargement (HRadjusted 0.55, 95% CI 0.39 to 0.79). AF risk in active participants with LA enlargement did not differ from active with normal LA size. These patterns were observed in both men and women, and in participants over/under 65 years.

CONCLUSION

Moderate PA was associated with reduced AF risk, and PA attenuated the increased risk of AF with LA enlargement in both men and women and all age groups.

Long-term efficacy and impact on quality of life of atrial fibrillation catheter ablation in competitive athletes

BACKGROUND

Limited data are available on the efficacy of catheter ablation (CA) for sport-associated atrial fibrillation (AF), in particular at long term follow up. Moreover, the impact of AF CA on quality of life (QoL) in this population remains unknown. We aimed to determine AF CA efficacy in athletes, to assess the impact on athletes' QoL (with SF36 score) and on training capabilities in a long term follow up (FU).

METHODS

A total of 1215 AF patients' candidates to CA between January 2007 and December 2012, were retrospectively screened. Athletes were defined as patients performing ≥ 5h/week of vigorous sports, achieving a total of ≥1500 h lifetime sports activity, for at least one year before AF first symptomatic episode.

RESULTS

Out of 1215 AF patients, 133 were considered competitive athletes and underwent to CA. Overall, 43% of our cohort showed typical or atypical atrial flutter, which required a more extensive ablation procedure. Before AF, athletes used to practice for a mean of 8.5±2.7 h/week, while after the first AF episode the mean practice duration decreased to 2.82.5 h/week. At 10-year follow up, 83% of athletes did not present any recurrent event, and training capabilities increased up to 5.6±3.6 h/week after the procedure. Moreover, intense physical activity before AF CA was related to longterm AF recurrence rates (P = 0.05). QoL scores significantly improved in each single domains (P < 0.05).

CONCLUSIONS

AF CA represents an effective procedure to maintain sinus rhythm in athletes, with a significant improvement in QoL.

New Radiomic Markers of Pulmonary Vein Morphology Associated With Post-Ablation Recurrence of Atrial Fibrillation

Objective: To identify radiomic and clinical features associated with post-ablation recurrence of AF, given that cardiac morphologic changes are associated with persistent atrial fibrillation (AF), and initiating triggers of AF often arise from the pulmonary veins which are targeted in ablation. Methods: Subjects with pre-ablation contrast CT scans prior to first-time catheter ablation for AF between 2014-2016 were retrospectively identified. A training dataset (D1) was constructed from left atrial and pulmonary vein morphometric features extracted from equal numbers of consecutively included subjects with and without AF recurrence determined at 1 year. The top-performing combination of feature selection and classifier methods based on C-statistic was evaluated on a validation dataset (D2), composed of subjects retrospectively identified between 2005-2010. Clinical models ([Formula: see text]) were similarly evaluated and compared to radiomic ([Formula: see text]) and radiomic-clinical models ([Formula: see text]), each independently validated on D2. Results: Of 150 subjects in D1, 108 received radiofrequency ablation and 42 received cryoballoon. Radiomic features of recurrence included greater right carina angle, reduced anterior-posterior atrial diameter, greater atrial volume normalized to height, and steeper right inferior pulmonary vein angle. Clinical features predicting recurrence included older age, greater BMI, hypertension, and warfarin use; apixaban use was associated with reduced recurrence. AF recurrence was predicted with radio-frequency ablation models on D2 subjects with C-statistics of 0.68, 0.63, and 0.70 for radiomic, clinical, and combined feature models, though these were not prognostic in patients treated with cryoballoon. Conclusions: Pulmonary vein morphology associated with increased likelihood of AF recurrence within 1 year of catheter ablation was identified on cardiac CT. Significance: Radiomic and clinical features-based predictive models may assist in identifying atrial fibrillation ablation candidates with greatest likelihood of successful outcome.

Correlation of heart rate recovery and heart rate variability with atrial fibrillation progression

Objective

To examine the combination of heart rate recovery (HRR) and heart rate variability (HRV) in predicting atrial fibrillation (AF) progression.

Methods

Data from patients with a first detected episode of AF who underwent treadmill exercise testing and 24-h Holter electrocardiography were retrospectively analysed. Autonomic dysfunction was verified using HRR values. Sympathetic and parasympathetic modulation was analysed by HRV. AF progression was defined as transition from the first detected paroxysmal episode to persistent/permanent AF.

Results

Of 306 patients, mean LF/HF ratio and HRR did not differ significantly by AF progression regardless of age (< or ≥65 years). However, when the LF/HF ratio was divided into tertiles, in patients aged <65 years, the mid LF/HF (1.60–2.40) ratio was significantly associated with lower AF progression rates and longer maintenance of normal sinus rhythm. For patients aged <65 years, less metabolic equivalents were related to higher AF progression rates. For patients aged ≥65 years, a low HRR was associated with high AF progression rates.

Conclusion

In relatively younger age, high physical capacity and balanced autonomic nervous system regulation are important predictors of AF progression. Evaluation of autonomic function assessed by age could predict AF progression.

Circulating Vascular Cell Adhesion Molecule-1 (sVCAM-1) Is Associated With Left Atrial Remodeling in Long-Distance Runners

Introduction: An increased risk of atrial fibrillation (AF) has been demonstrated in high-performance athletes. Soluble vascular adhesion molecule-1 (sVCAM-1), a biomarker involved in inflammation and cardiac remodeling, is associated with the development of AF in the general population. However, the relationship between sVCAM-1 and left atrial (LA) remodeling has been poorly investigated in long-distance runners (LDR).

Aim: To determine the association between LA remodeling and sVCAM-1 levels in LDR during the training period before a marathon race.

Methods: Thirty-six healthy male LDR (37.0 ± 5.3 years; 174.0 ± 7.0 height; BMI: 23.8 ± 2.8; V°O₂-peak: 56.5 ± 7.3 mL·kg⁻¹·min⁻¹) were evaluated in this single-blind and cross-sectional study. The LDR were separated into two groups according to previous training levels: high-training (HT) (n = 18) ≥100 km·week⁻¹ and low-training (LT) (n = 18) ≥70 and <100 km·week⁻¹. Also, 18 healthy non-active subjects were included as a control group (CTR). In all participants, transthoracic echocardiography was performed. sVCAM-1 blood levels were measured baseline and immediately finished the marathon race in LDR.

Results: HT showed increased basal levels of sVCAM-1 (651 ± 350 vs. 440 ± 98 ng·mL⁻¹ CTR, p = 0.002; and vs. 533 ± 133 ng·mL⁻¹ LT; p = 0.003) and a post-marathon increase (ΔsVCAM-1) (651 ± 350 to 905 ± 373 ng·mL⁻¹; p = 0.002), that did not occur in LT (533 ± 133 to 651 ± 138 ng·mL⁻¹; p = 0.117). In LDR was a moderate correlation between LA volume and sVCAM-1 level (rho = 0.510; p = 0.001).

Conclusions: In male long-distance runners, sVCAM-1 levels are directly associated with LA remodeling. Also, the training level is associated with basal sVCAM-1 levels and changes after an intense and prolonged exercise (42.2 km). Whether sVCAM-1 levels predict the risk of AF in runners remains to be established.

Clinical Features of LMNA-Related Cardiomyopathy in 18 Patients and Characterization of Two Novel Variants

Dilated cardiomyopathy (DCM) refers to a spectrum of heterogeneous myocardial disorders characterized by ventricular dilation and depressed myocardial performance in the absence of hypertension, valvular, congenital, or ischemic heart disease. Mutations in LMNA gene, encoding for lamin A/C, account for 10% of familial DCM. LMNA-related cardiomyopathies are characterized by heterogeneous clinical manifestations that vary from a predominantly structural heart disease, mainly mild-to-moderate left ventricular (LV) dilatation associated or not with conduction system abnormalities, to highly pro-arrhythmic profiles where sudden cardiac death (SCD) occurs as the first manifestation of disease in an apparently normal heart. In the present study, we select, among 77 DCM families referred to our center for genetic counselling and molecular screening, 15 patient heterozygotes for LMNA variants. Segregation analysis in the relatives evidences other eight heterozygous patients. A genotype-phenotype correlation has been performed for symptomatic subjects. Lastly, we perform in vitro functional characterization of two novel LMNA variants using dermal fibroblasts obtained from three heterozygous patients, evidencing significant differences in terms of lamin expression and nuclear morphology. Due to the high risk of SCD that characterizes patients with lamin A/C cardiomyopathy, genetic testing for LMNA gene variants is highly recommended when there is suspicion of laminopathy.

Left Atrial Myopathy in Heart Failure With Preserved Ejection Fraction

The left atrium (LA) plays an important role in facilitating left ventricular (LV) filling by acting as a reservoir, passive conduit, and active booster pump, as well as a regulator of blood volume through A-type natriuretic peptide secretion in response to stimulation by mechanical stretch of the cavity. LA myopathy has emerged as one of the most important non-LV contributors to disease progression in heart failure with preserved ejection fraction (HFpEF). LA dysfunction is common in HFpEF and is associated with more severe pulmonary vascular disease and right ventricular dysfunction, and increases the risk of incident atrial fibrillation or atrial functional mitral regurgitation, leading to limitations in cardiac output reserve and reduced exercise capacity. LA deformation assessed by 2-dimensional speckle-tracking echocardiography is useful for estimating abnormal hemodynamics or exercise capacity, discriminating HFpEF from non-cardiac dyspnea and is an independent predictor of adverse outcome in HFpEF. Thus, interventions directly targeting LA myopathy may improve outcomes in HFpEF with LA myopathy. This review provides information regarding the physiology of the LA in patients with HFpEF and discusses the importance of evaluation of LA function, management issues, and future directions through ongoing trials of medical interventions.

Day-to-day measurement of physical activity and risk of atrial fibrillation

Aims 

The aim of this study was to investigate the association between within-individual changes in physical activity and onset of atrial fibrillation (AF).

Methods and results 

A total of 1410 participants from the general population (46.2% women, mean age 74.7 ± 4.1 years) with risk factors but with no prior AF diagnosis underwent continuous monitoring for AF episodes along with daily accelerometric assessment of physical activity using an implantable loop recorder during ≈3.5 years. The combined duration of monitoring was ≈1.6 million days, where 10 851 AF episodes lasting ≥60 min were detected in 361 participants (25.6%) with a median of 5 episodes (2, 25) each. The median daily physical activity was 112 (66, 168) min/day. A dynamic parameter describing within-individual changes in daily physical activity, i.e. average daily activity in the last week compared to the previous 100 days, was computed and used to model the onset of AF. A 1-h decrease in average daily physical activity was associated with AF onset the next day [odds ratio 1.24 (1.18–1.31)]. This effect was modified by overall level of activity (P < 0.001 for interaction), and the signal was strongest in the tertile of participants with lowest activity overall [low: 1.62 (1.41–1.86), mid: 1.27 (1.16–1.39), and high: 1.10 (1.01–1.19)].

Conclusions 

Within-individual changes in physical activity are associated with the onset of AF episodes as detected by continuous monitoring in a high-risk population. For each person, a 1-h decrease in daily physical activity during the last week increased the odds of AF onset the next day by ≈25%, while the strongest association was seen in the group with the lowest activity overall.

Clinical Trial Registration

ClinicalTrials.gov, identifier: NCT02036450.

Potential Long-Term Health Problems Associated with Ultra-Endurance Running: A Narrative Review

It is well established that physical activity reduces all-cause mortality and can prolong life. Ultra-endurance running (UER) is an extreme sport that is becoming increasingly popular, and comprises running races above marathon distance, exceeding 6 h, and/or running fixed distances on multiple days. Serious acute adverse events are rare, but there is mounting evidence that UER may lead to long-term health problems. The purpose of this review is to present the current state of knowledge regarding the potential long-term health problems derived from UER, specifically potential maladaptation in key organ systems, including cardiovascular, respiratory, musculoskeletal, renal, immunological, gastrointestinal, neurological, and integumentary systems. Special consideration is given to youth, masters, and female athletes, all of whom may be more susceptible to certain long-term health issues. We present directions for future research into the pathophysiological mechanisms that underpin athlete susceptibility to long-term issues. Although all body systems can be affected by UER, one of the clearest effects of endurance exercise is on the cardiovascular system, including right ventricular dysfunction and potential increased risk of arrhythmias and hypertension. There is also evidence that rare cases of acute renal injury in UER could lead to progressive renal scarring and chronic kidney disease. There are limited data specific to female athletes, who may be at greater risk of certain UER-related health issues due to interactions between energy availability and sex-hormone concentrations. Indeed, failure to consider sex differences in the design of female-specific UER training programs may have a negative impact on athlete longevity. It is hoped that this review will inform risk stratification and stimulate further research about UER and the implications for long-term health.

Exercising immune cells: The immunomodulatory role of exercise on atrial fibrillation

Exercise training is generally beneficial for cardiovascular health, improving stroke volume, cardiac output, and aerobic capacity. Despite these benefits, some evidence indicates that endurance training may increase the risk of atrial fibrillation (AF), particularly in highly trained individuals. Among multiple mechanisms, autonomic tone changes and atrial remodeling have been proposed as main contributors for exercise-induced AF. However, the contribution of local and systemic immunity is poorly understood in the development of atrial arrhythmogenic substrates. Here we aim to update the field of immunomodulation in the context of exercise and AF by compiling and reconciling the most recent evidence from preclinical and human studies and rationalize the applicability of "lone" AF terminology in athletes.

Adult height and incidence of atrial fibrillation and heart failure in older men: The British Regional Heart Study

Aims

Taller stature has been associated with increased risk of atrial fibrillation (AF). AF and heart failure (HF) often co-occur but the association between height and risk of HF in older adults has not been well studied. We have examined the association between height and incident AF and incident HF in older adults.

Methods

Prospective study of 3346 men aged 60–79 years with no diagnosed HF, myocardial infarction or stroke at baseline (1998–2000) followed up for a mean period of 16 years, in whom there were 294 incident HF cases and 456 incident AF. Men were divided into 5 height groups: <168.2, 168.2–172.5, 172.6–176.9, 177.0–183.0 and >183.0 cms based on the 25th, 50th, 75th and 95th centiles distribution of height.

Results

CVD risk factors tended to decrease with increasing height but a positive association was seen between height and electrocardiographic QRS duration and incident AF. Both short stature (<168.2 cm) and tall stature (>183.0 cm) was associated with significantly increased risk of HF in age-adjusted analysis compared to those in the second height quartile [HR (95 %CI) = 1.62 (1.15, 2.26) and 2.04 (1.23, 3.39) respectively]. In short men the increased risk remained after adjustment for adverse CVD risk factors; in tall men the association was largely associated with AF and QRS duration.

Conclusion

Tall stature is associated with significantly increased risk of AF leading to increased risk of HF. Short stature was associated with increased HF risk which was not explained by known adverse CVD risk factors.

Genetic Thyrotropin Regulation of Atrial Fibrillation Risk Is Mediated Through an Effect on Height

CONTEXT

A genetic predisposition to lower thyrotropin (TSH) levels is associated with increased atrial fibrillation (AF) risk through undefined mechanisms.

OBJECTIVE

Defining the genetic mediating mechanisms could lead to improved targeted therapies to mitigate AF risk.

METHODS

We used 2-sample mendelian randomization (MR) to test associations between TSH-associated single-nucleotide variations and 16 candidate mediators. We then performed multivariable mendelian randomization (MVMR) to test for a significant attenuation of the genetic association between TSH and AF, after adjusting for each mediator significantly associated with TSH.

RESULTS

Four candidate mediators (free thyroxine, systolic blood pressure, heart rate, and height) were significantly inversely associated with genetically predicted TSH after adjusting for multiple testing. In MVMR analyses, adjusting for height significantly decreased the magnitude of the association between TSH and AF from -0.12 (SE 0.02) occurrences of AF per SD change in height to -0.06 (0.02) (P = .005). Adjusting for the other candidate mediators did not significantly attenuate the association.

CONCLUSION

The genetic association between TSH and increased AF risk is mediated, in part, by taller stature. Thus, some genetic mechanisms underlying TSH variability may contribute to AF risk through mechanisms determining height occurring early in life that differ from those driven by thyroid hormone-level elevations in later life.

Heritability estimates of atrial fibrillation in Thoroughbred racehorses in Hong Kong and Australia

INTRODUCTION

Atrial fibrillation (AF) is the most common performance-limiting arrhythmia of racehorses. A genetic contribution has been suggested in Standardbred racehorses but has not been investigated in Thoroughbreds. The objective of this study was to determine the heritability of AF in Thoroughbred racehorses.

ANIMALS, MATERIALS AND METHODS

Horses racing between 2007 and 2019 in Hong Kong and Australia that had AF detected postrace via auscultation (n = 463 cases) were compared with five randomly selected racing contemporaries (n = 2,315 controls). The ASReml-R programme was used to fit an animal model to the AF data to estimate heritability using the entire data set and a subset of horses (n = 106 cases) that had electrocardiographic confirmation of AF. Variance components were estimated assuming AF was normally distributed and on the logit-transformed scale. The risk of producing AF-affected offspring was calculated using Fisher's exact test for stallions that sired ≥10 individuals in the case-control population.

RESULTS

Heritability on the underlying scale was 0.064 ± 0.04 (logit animal) and 0.071 ± 0.04 (normal animal) for the entire population and 0.065 ± 0.097 (logit animal) and 0.058 ± 0.11 (normal animal) for electrocardiographic-confirmed AF cases. Of 71 stallions that sired ≥10 individuals, three were more likely to produce affected offspring (odds ratio: 4.05-7.57; p < 0.01). Age (p = 0.991), sex (p = 0.830), and year of birth (p = 0.547) did not contribute to expression.

CONCLUSIONS

Although some stallions were overrepresented amongst affected horses, the heritability of AF in this population of Thoroughbreds was low. Environmental and individual factors contributing to AF development require further investigation.

Utility of cardiovascular implantable electronic device-derived patient activity to predict clinical outcomes

BACKGROUND

The role of cardiovascular implantable electronic device (CIED)-derived activity to predict implantable cardioverter-defibrillator (ICD) therapy or death is not known.

OBJECTIVE

We aimed to assess CIED-derived activity to predict clinical outcomes.

METHODS

In 1500 patients enrolled in MADIT-RIT, CIED-derived patient activity was acquired daily, then averaged for the first 30 days following randomization to predict inappropriate/appropriate therapy or death. Kaplan-Meier analysis and Cox proportional regression models were used to evaluate inappropriate/appropriate therapy, heart failure, or death by 30-day CIED-derived patient activity quintiles.

RESULTS

There were 1463 patients with CIED activity data (98%). Patients in the highest quintile (Q5) of activity (more active) had the highest rate of inappropriate therapy, 21% at 2 years, as compared to 7%-11% in the other 4 quintiles (P < .001), a 1.75 times higher risk (95% confidence interval [CI]: 1.23-2.50, P = .002). However, patients in the lowest quintile of activity (Q1, 1 hour/day) had the highest risk of mortality, 15% in 2 years, as compared to Q2-3 (1-2 hours/day, 8%-7% mortality), and Q4-5 (>2 hours/day, 2%-3% mortality) (P < .001). Patients with the lowest level of activity (Q1) had a 2.02 times higher risk of mortality (95% CI: 1.21-3.38, P = .007), and they had an 82% higher risk of heart failure hospitalization (95% CI: 1.28-2.57, P = .001).

CONCLUSIONS

High CIED-derived 30-day median patient activity predicted inappropriate therapy, while low patient activity predicted mortality and heart failure in ICD and cardiac resynchronization therapy with defibrillator patients enrolled in MADIT-RIT. Device-derived activity assessment could serve as a useful predictor of outcomes.

Electrocardiographic Changes in Male and Female Amateur Marathon Runners: A Comparison Study

Physical training is gaining popularity among amateurs. Males and females exhibit different cardiac adaptation to exercise. The aim of the study was to compare the incidence of electrocardiographic abnormalities before and after the marathon between sexes. 12-lead electrocardiogram was performed in 40 male (39±8 years) and 27 female (40±7 years) amateur runners: 2-3 weeks before (Stage 1) and immediately after (Stage 2) the marathon. Abnormalities in the resting (Stage 1) and exercise (Stage 2) electrocardiograms were compared between sexes. At rest left atrial enlargement was more frequent in females than males (48 vs. 20%; p<0.05). The incidence of right atrial enlargement was significantly more common at Stage 2 than 1, both in men (43 vs. 0%; p<0.001) and in women (48 vs. 4%; p=0.001). Significant increase of P-wave amplitude was found in male runners after the marathon (0.12±0.05 vs. 0.21±0.09 mV; p<0.001 Stage 1 vs. 2), but was absent in females. QTc prolongation was observed in both sexes, however to a higher degree in males (p<0.05 for the interaction stage and sex). Although both male and female amateur marathon runners exhibit abnormalities in resting and exercise electrocardiograms, men present more exercise-induced electrocardiographic changes, which might indicate a higher propensity for post-marathon arrhythmias. Electrocardiographic screening in amateurs should be considered.

Exercise and Athletic Activity in Atrial Fibrillation

Moderate-intensity exercise improves cardiovascular outcomes. However, mounting clinical evidence demonstrates that long-term, high-intensity endurance training predisposes male and veteran athletes to an increased risk of atrial fibrillation (AF), a risk that is not observed across both genders. Although increased mortality associated with AF in the general population is not shared by athletes, clinically significant morbidities exist (eg, reduced exercise capacity, athletic performance, and quality of life). Additional research is needed to fill current gaps in knowledge pertaining to the natural history, pathophysiologic mechanisms, and management strategies of AF in the athlete.

Association of physical activity and risk of atrial fibrillation in heart failure with preserved ejection fraction

BACKGROUND AND AIMS

Physical activity (PA) could modify the risk of atrial fibrillation (AF) in the general population and mortality in heart failure patients with preserved ejection fraction (HFpEF). HFpEF patients are frequently concomitant with AF, but whether PA could modify the risk of AF in HFpEF patients remains undiscovered.

METHOD AND RESULTS

We performed a post hoc analysis of the TOPCAT trial. Patients without AF at baseline and with data on PA (n = 652) were included. The association between PA and risk of AF occurrence was explored using the Cox proportional hazard model. During a median follow-up of 2.84 years, 9.4% of the studied patients (n = 60) had an occurrence of AF. When PA was analyzed as a continuous variable, every ten-fold increase of PA was associated with a 42.8% risk reduction of AF occurrence (hazard ratio [HR] 0.572, 95% CI 0.357-0.916, p = 0.020). When HFpEF patients were divided into three tertile groups according to PA levels, patients in the second tertile (HR 0.507, 95% CI 0.272-0.946, p = 0.033) and the third tertile (HR 0.487, 95% CI 0.261-0.908, p = 0.024) had significantly lower risks of AF occurrence when compared to those in the first tertile.

CONCLUSIONS

Our current results suggest that a higher PA level associates with a lower risk of AF in HFpEF patients.

CLINICAL TRIAL REGISTRATION

URL: https://clinicaltrials.gov. Unique identifier: NCT00094302.

High fitness might be associated with the development of new-onset atrial fibrillation in obese non-athletic adults

BACKGROUND

Data on the association between AF and fitness are conflicting.

OBJECTIVES

The aim of this analysis was to investigate the association between fitness, obesity and incidence of atrial fibrillation (AF) among apparently healthy non-athlete adults.

METHODS

We investigated 20 410 self-referred subjects who were annually screened in a tertiary medical centre. All subjects were free of AF and completed maximal exercise stress test according to the Bruce protocol at baseline. Fitness was categorised into age- and sex-specific quintiles (Q) according to the treadmill time. Subjects were categorised to low (Q1-Q2) and high fitness (Q3-5) groups. The primary end point was new-onset AF during follow-up.

RESULTS

Mean age was 48 ± 10 years and 72% were men. A total of 463 (2.3%) events occurred during an average follow-up of 8 ± 5 years corresponding to an AF event rate of 0.3% per person year. Univariate and multivariate models showed that AF risk was similar in both fitness groups. However, AF event rate was 0.55% per person year among high fitness obese subjects, compared with 0.31% for low fitness obese subjects (P < .01). Subgroup interaction analysis showed that AF risk is obesity-dependent, such that in the obese group (≥30 kg/m² ) high fitness was independently associated with a significant 79% increased AF risk (95% CI 1.15-2.78; P = .01), whereas among non-obese subjects the rate of events was similar between both fitness groups (P for interaction = (.02)).

CONCLUSIONS

Our findings suggest that high fitness might be associated with increased AF risk among obese subjects.

The height as an independent risk factor of atrial fibrillation: A review

Atrial fibrillation (AF) is characterized by abnormal heart rhythm. Among other well-known associations, recent studies suggest an association of AF with height. Height is related to 50 diseases spanning different body systems, AF is one of them. Since AF, a heterogeneous disease process, is influenced by structural, neural, electrical, and hemodynamic factors, height alters this process through its contribution to increasing atrial and ventricular size, leading to altered conduction patterns, autonomic dysregulation, and development of AF. Multiple underlying mechanisms associate height with AF. Apart from these indirect mechanisms, genome-wide association studies suggest the involvement of the same genes in AF and growth pathways. Tall stature is independently associated with a higher risk of AF development in healthy individuals. Since adult height is achieved much earlier than the onset of AF, protective measures can be taken in individuals with increased height to monitor, manage, and prevent the progression of AF.

Genetics of height and risk of atrial fibrillation: A Mendelian randomization study

BACKGROUND

Observational studies have identified height as a strong risk factor for atrial fibrillation, but this finding may be limited by residual confounding. We aimed to examine genetic variation in height within the Mendelian randomization (MR) framework to determine whether height has a causal effect on risk of atrial fibrillation.

METHODS AND FINDINGS

In summary-level analyses, MR was performed using summary statistics from genome-wide association studies of height (GIANT/UK Biobank; 693,529 individuals) and atrial fibrillation (AFGen; 65,446 cases and 522,744 controls), finding that each 1-SD increase in genetically predicted height increased the odds of atrial fibrillation (odds ratio [OR] 1.34; 95% CI 1.29 to 1.40; p = 5 × 10-42). This result remained consistent in sensitivity analyses with MR methods that make different assumptions about the presence of pleiotropy, and when accounting for the effects of traditional cardiovascular risk factors on atrial fibrillation. Individual-level phenome-wide association studies of height and a height genetic risk score were performed among 6,567 European-ancestry participants of the Penn Medicine Biobank (median age at enrollment 63 years, interquartile range 55-72; 38% female; recruitment 2008-2015), confirming prior observational associations between height and atrial fibrillation. Individual-level MR confirmed that each 1-SD increase in height increased the odds of atrial fibrillation, including adjustment for clinical and echocardiographic confounders (OR 1.89; 95% CI 1.50 to 2.40; p = 0.007). The main limitations of this study include potential bias from pleiotropic effects of genetic variants, and lack of generalizability of individual-level findings to non-European populations.

CONCLUSIONS

In this study, we observed evidence that height is likely a positive causal risk factor for atrial fibrillation. Further study is needed to determine whether risk prediction tools including height or anthropometric risk factors can be used to improve screening and primary prevention of atrial fibrillation, and whether biological pathways involved in height may offer new targets for treatment of atrial fibrillation.

The effects of endurance exercise on the heart: panacea or poison?

Regular aerobic physical exercise of moderate intensity is undeniably associated with improved health and increased longevity, with some studies suggesting that more is better. Endurance athletes exceed the usual recommendations for exercise by 15-fold to 20-fold. The need to sustain a large cardiac output for prolonged periods is associated with a 10-20% increase in left and right ventricular size and a substantial increase in left ventricular mass. A large proportion of endurance athletes have raised levels of cardiac biomarkers (troponins and B-type natriuretic peptide) and cardiac dysfunction for 24-48 h after events, but what is the relevance of these findings? In the longer term, some endurance athletes have an increased prevalence of coronary artery disease, myocardial fibrosis and arrhythmias. The inherent association between these 'maladaptations' and sudden cardiac death in the general population raises the question of whether endurance exercise could be detrimental for some individuals. However, despite speculation that these abnormalities confer an increased risk of future adverse events, elite endurance athletes have an increased life expectancy compared with the general population.

Atrial fibrillation is associated with lean body mass in postmenopausal women

This study investigated the association between body composition and risk of atrial fibrillation (AF) in postmenopausal women. In a retrospective analysis we assessed data from 5704 postmenopausal women (age 70.7 ± 6.5 yrs.) who in 1999–2001 participated in The Prospective Epidemiological Risk Factor study with body composition assessed by dual-energy X-ray absorptiometry. Outcomes were obtained from Danish Health Registries and body composition association to risk of AF was evaluated by univariable and multivariable Cox Hazard regression. 850 women developed AF after baseline. High lean body mass was associated with increased risk of AF in multivariable analyses, adjusting for body mass index (BMI), height or weight (adjusted for: BMI, hazard ratio (HR) 1.49, 95% Confidence Interval (1.22–1.80); height, HR 1.27 (1.03–1.56); weight, 1.33 (1.06–1.65)). Height and weight were associated with increased risk of AF in multivariable analyses adjusting for body composition measures. When adjusting for total lean mass, only height remained statistically significant (HR 1.34 (1.09–1.64)). In a cohort of elderly Caucasian women, high lean body mass, height and weight were associated with increased risk of AF and the variables remained significant after adjusting for age and other known risk factors of AF.

Height is associated with incident atrial fibrillation in a large Asian cohort

BACKGROUND

Although increased height is associated with a risk of atrial fibrillation (AF), the mechanism is not well understood. We aimed to explore whether this association varies with metabolic conditions.

METHODS AND RESULTS

We used the database from the 14-year Korea National Health Insurance Service-National Sample Cohort. The data of 368,206 adults older than 20 years who received a health check-up were analyzed to explore the association of height and AF risk. Cox proportional hazards regression models were used to compute hazard ratios (HRs) and 95% confidence intervals (CIs) for associations of height with the risk of AF. During the median follow up duration of 8.46 years, 2641 (0.72%) patients were diagnosed with AF at 3,070,724 person-years. Overall, greater height was significantly associated with AF risk (HR per 5 cm, 1.22; 95% CI, 1.03-1.05). The association did not vary with age, sex, obesity, hypertension, and diabetes.

CONCLUSION

Metabolic conditions do not affect the higher risk of AF in tall people.

Left Atrial Electromechanical Remodeling Following 2 Years of High-Intensity Exercise Training in Sedentary Middle-Aged Adults

BACKGROUND

Moderate intensity exercise is associated with a decreased incidence of atrial fibrillation. However, extensive training in competitive athletes is associated with an increased atrial fibrillation risk. We evaluated the effects of 24 months of high intensity exercise training on left atrial (LA) mechanical and electric remodeling in sedentary, healthy middle-aged adults.

METHODS

Sixty-one participants (53±5 years) were randomized to 10 months of exercise training followed by 14 months of maintenance exercise or stretching/balance control. Fourteen Masters athletes were added for comparison. Left ventricular (LV) and LA volumes underwent 3D echocardiographic assessment, and signal-averaged electrocardiographs for filtered P-wave duration and atrial late potentials were completed at 0, 10, and 24 months. Extended ambulatory monitoring was performed at 0 and 24 months. Within and between group differences from baseline were compared using mixed-effects model repeated-measures analysis.

RESULTS

Fifty-three participants completed the study (25 control, 28 exercise) with 88±11% adherence to assigned exercise sessions. In the exercise group, both LA and LV end diastolic volumes increased proportionately (19% and 17%, respectively) after 10 months of training (peak training load). However, only LA volumes continued to increase with an additional 14 months of exercise training (LA volumes 55%; LV end diastolic volumes 15% at 24 months versus baseline; P<0.0001 for all). The LA:LV end diastolic volumes ratio did not change from baseline to 10 months, but increased 31% from baseline in the Ex group ( P<0.0001) at 24 months, without a change in controls. There were no between group differences in the LA ejection fraction, filtered P-wave duration, atrial late potentials, and premature atrial contraction burden at 24 months and no atrial fibrillation was detected. Compared with Masters athletes, the exercise group demonstrated lower absolute LA and LV volumes, but had a similar LA:LV ratio after 24 months of training.

CONCLUSIONS

Twenty-four months of high intensity exercise training resulted in LA greater than LV mechanical remodeling with no observed electric remodeling. Together, these data suggest different thresholds for electrophysiological and mechanical changes may exist in response to exercise training, and provide evidence supporting a potential mechanism by which high intensity exercise training leads to atrial fibrillation.

CLINICAL TRIAL REGISTRATION

URL: https://www.clinicaltrials.gov . Unique identifier: NCT02039154.

Atrial Fibrillation in Athletes-Features of Development, Current Approaches to the Treatment, and Prevention of Complications

Atrial fibrillation (AF) is one of the most common types of cardiac arrhythmias. This review article highlights the problem of the development of atrial fibrillation in individuals engaged in physical activity and sports. Predisposing factors, causes, and development mechanisms of atrial fibrillation in athletes from the perspective of the authors are described. Methods of treatment, as well as prevention of thromboembolic complications, are discussed. Directions for further studies of this problem and prevention of complications are proposed.

The effect of cardiac rehabilitation at 4 weeks postoperatively on quality of life in patients treated with totally thoracoscopic ablation

There is a lack of evidence on the effect of exercise-based cardiac rehabilitation (EBCR) in patients treated with total thoracoscopic ablation (TTA) for atrial fibrillation (AF). Our study investigated the efficacy and safety of postoperative exercise intervention in patients recovering from TTA. Twenty-four patients participated in the study, and were divided into the two groups, exercise group (EG) (n=12) and control group (n= 12). Patients in EG performed the exercise intervention including the aerobic and resistance exercise program twice a week for 8 weeks, which was used as a hospital-based cardiac rehabilitation for the out-patient. A cardiopulmonary exercise test was administered to evaluate aerobic exercise capacity, and qualitative aspect of patient’s life was assessed using the Short Form 36 questionnaires to compare pre and postoperative wellness of patient’s life. Although there was an increase of VO_2peak (peak oxygen uptake) after exercise intervention, no significant improvement was found (P=0.055). Two of 4 physical health scores (role-physical, P=0.013 and general health, P=0.05) and three of four mental health scores (vitality, P=0.027, social function, P=0.016, and mental health, P=0.003) were significantly improved after 8 weeks of EBCR. Each summarized scale in the physical (P=0.022) and mental (P= 0.004) survey section was also significantly improved in postoperative assessment compared to the preoperative one. In this context, we concluded that EBCR initiated at the time point of 4th week after TTA operation can guarantee the secure postoperative physical activity, and the 8 weeks of EBCR can effectively improve the quality of life in AF Patients.

Supraventricular Arrhythmias in Athletes: Basic Mechanisms and New Directions

Athletes are prone to supraventricular rhythm disturbances including sinus bradycardia, heart block, and atrial fibrillation. Mechanistically, this is attributed to high vagal tone and cardiac electrical and structural remodeling. Here, we consider the supporting evidence for these three pro-arrhythmic mechanisms in athletic human cohorts and animal models, featuring current controversies, emerging data, and future directions of relevance to the translational research agenda.

Does High-Intensity Endurance Training Increase the Risk of Atrial Fibrillation? A Longitudinal Study of Left Atrial Structure and Function

BACKGROUND

Exercise mitigates many cardiovascular risk factors associated with atrial fibrillation. Endurance training has been associated with atrial structural changes which can increase the risk for atrial fibrillation. The dose of exercise training required for these changes is uncertain. We sought to evaluate the impact of exercise on left atrial (LA) mechanical and electrical function in healthy, sedentary, middle-aged adults.

METHODS

Sixty-one adults (52±5 years) were randomized to either 10 months of high-intensity exercise training or yoga. At baseline and post-training, all participants underwent maximal exercise stress testing to assess cardiorespiratory fitness, P-wave signal-averaged electrocardiography for filtered P-wave duration and atrial late potentials (root mean square voltage of the last 20 ms), and echocardiography for LA volume, left ventricular end-diastolic volume, and mitral inflow for assessment of LA active emptying. Post-training data were compared with 14 healthy age-matched Masters athletes.

RESULTS

LA volume, Vo₂ max, and left ventricular end-diastolic volume increased in the exercise group (15%, 17%, and 16%, respectively) with no change in control (P<0.0001). LA active emptying decreased post-exercise versus controls (5%; P=0.03). No significant changes in filtered P-wave duration or root mean square voltage of the last 20 ms occurred after exercise training. LA and left ventricular volumes remained below Masters athletes. The athletes had longer filtered P-wave duration but no difference in the frequency of atrial arrhythmia.

CONCLUSIONS

Changes in LA structure, LA mechanical function, and left ventricular remodeling occurred after 10 months of exercise but without significant change in atrial electrical activity. A longer duration of training may be required to induce electrical changes thought to cause atrial fibrillation in middle-aged endurance athletes.

CLINICAL TRIAL REGISTRATION

URL: https://www.clinicaltrials.gov. Unique Identifier: NCT02039154.

Prolonged P wave duration is associated with right atrial dimensions, but not atrial arrhythmias, in middle-aged endurance athletes

BACKGROUND

Atrial arrhythmias occur at a higher than expected prevalence amongst endurance athletes. Few studies have examined both atrial structure and arrhythmias in middle-aged endurance athletes. We examined the relationship between P-wave duration, atrial dimensions, and the presence of atrial ectopy in long-standing, middle-aged endurance athletes.

METHODS

Middle-aged athletes with a minimum of 10 years of competitive endurance sport history and no history of structural heart disease or clinical atrial arrhythmias, had 12-lead ECGs to assess P-wave duration, signal-averaged ECGs (SAECG) to assess filtered P-wave duration, a 24 h Holter monitor to assess atrial ectopy, and echocardiography and cardiac magnetic resonance imaging to assess atrial structural characteristics.

RESULTS

Amongst endurance athletes (n = 104; mean age = 54 ± 5 years; 63% male), filtered P-wave duration on SAECG was correlated with P-wave duration on 12-lead ECG (r = 0.36, p, 0.0001), as well as with larger CMR-derived RA areas (r = 0.30, p = 0.01) and volumes (r = 0.24, p < 0.05). There was no correlation between filtered P-wave duration and any LA measures on imaging (p > 0.05). There was no correlation between the incidence of atrial ectopy (premature atrial contractions or atrial tachycardia) and any electrocardiographic or structural measures.

CONCLUSION

Longer filtered P-wave duration was associated with larger RA areas and volumes, without an increase in atrial ectopy.

Development and external validation of predictive models for prevalent and recurrent atrial fibrillation: a protocol for the analysis of the CATCH ME combined dataset

BACKGROUND

Atrial fibrillation (AF) is caused by different mechanisms but current treatment strategies do not target these mechanisms. Stratified therapy based on mechanistic drivers and biomarkers of AF have the potential to improve AF prevention and management outcomes. We will integrate mechanistic insights with known pathophysiological drivers of AF in models predicting recurrent AF and prevalent AF to test hypotheses related to AF mechanisms and response to rhythm control therapy.

METHODS

We will harmonise and combine baseline and outcome data from 12 studies collected by six centres from the United Kingdom, Germany, France, Spain, and the Netherlands which assess prevalent AF or recurrent AF. A Delphi process and statistical selection will be used to identify candidate clinical predictors. Prediction models will be developed in patients with AF for AF recurrence and AF-related outcomes, and in patients with or without AF at baseline for prevalent AF. Models will be used to test mechanistic hypotheses and investigate the predictive value of plasma biomarkers.

DISCUSSION

This retrospective, harmonised, individual patient data analysis will use information from 12 datasets collected in five European countries. It is envisioned that the outcome of this analysis would provide a greater understanding of the factors associated with recurrent and prevalent AF, potentially allowing development of stratified approaches to prevention and therapy management.

Ten-year ablation outcomes of patients with paroxysmal atrial fibrillation undergoing pulmonary vein isolation

BACKGROUND

Pulmonary vein isolation (PVI) is commonly performed in patients with drug-refractory symptomatic paroxysmal atrial fibrillation (PAF). However, the very long-term follow-up result is limited.

OBJECTIVE

We aimed to investigate 10-year ablation outcomes in patients with PAF and long-term follow-up results after PVI.

METHODS

This study retrospectively enrolled 176 (131 men, mean age 51.2 ± 12.1 years) patients with drug-refractory symptomatic PAF who underwent electroanatomic-guided PVI. Ten-year follow-up was completed using medical records or telephonic interviews. Procedural characteristics at index procedures and long-term clinical outcomes were investigated.

RESULTS

After a mean follow-up period of 130.0 ± 10.8 months, sinus rhythm was achieved in 102 (58%) patients after a single procedure (including 14 (8%) patients on antiarrhythmic medications) and in 88% patients after multiple procedures (including 17 (10%) patients on antiarrhythmic medications). Left atrial diameter (odds ratio 1.067; 95% confidence interval 1.009-1.127; P = .023) was the predictor of recurrent atrial tachyarrhythmia after a single ablation procedure. The single-procedure recurrence-free rates were similar between circumferential PVI and segmental PVI (59% and 50%; log-rank, P = .251). The recurrence patterns of both groups regarding the role of non-pulmonary vein and pulmonary vein triggers were similar.

CONCLUSION

The single-procedure long-term efficacy was modest, with freedom from atrial fibrillation at 10 years being 58%. Those who had enlarged left atrial diameters have more atrial tachyarrhythmia recurrences. Ten-year single-procedure outcomes of the effects of circumferential PVI and segmental PVI in patients with PAF were similar.

Association between self-reported physical activity and incident atrial fibrillation in a young Korean population

The association between physical activity (PA) and atrial fibrillation (AF) remains unclear. We thus investigated association of PA with the development of AF. Type and duration data for PA were acquired from 211,992 AF-free individuals using the validated Korean version of the International Physical Activity Questionnaire Short From between March 2002 and December 2014. Individuals were divided into four groups according to self-reported PA level and previous international PA guidelines: no PA with a sedentary lifestyle, insufficient PA, sufficient PA, and health-enhancing PA. AF was diagnosed by annual 12-lead electrocardiogram. During a median follow-up of 5.6 years, AF occurred in 304 participants (annual AF incidence rate 2.5/10,000 person-years). After adjusting for age and sex, PA level was not associated with AF incidence (P for trend = 0.26). The multivariable-adjusted hazard ratios (95% confidence interval) for incidental AF was 1.00 (0.74–1.37) for the insufficient PA group, 1.34 (0.91–1.97) for the sufficient PA group, and 1.27 (0.72–2.23) for the health-enhancing PA group compared with the no PA group (P for trend = 0.18). Thus, our study does not support an association between the risk of AF and PA level in a young Korean population.

Cardiac Risk of Extreme Exercise

Habitual moderate intensity exercise is a vital component of a healthy lifestyle. For most of the population, increasing exercise duration and intensity beyond current recommendations appears to impart additional cardiovascular benefits; however, recent data has raised the possibility of an inflection point after which additional exercise no longer imparts benefit and may even result in negative cardiovascular outcomes. Exercise at the extremes of human endurance places a large hemodynamic stress on the heart and results in occasionally profound cardiac remodeling in order to accommodate the huge increases in cardiac output demanded by such endeavors. These changes have the potential to become maladaptive and heighten the risk of various arrhythmias, influence the rate of coronary atherosclerosis, and alter the risk of sudden cardiac death. Herein, we will discuss the potential negative impact of extreme exercise on cardiovascular risk.