Very brief intervention for physical activity behaviour change in cardiac rehabilitation: protocol for the 'Measure It!' effectiveness-implementation hybrid trial.

INTRODUCTION: Physical inactivity is a risk factor for repeat cardiac events and all-cause mortality in coronary heart disease (CHD). Cardiac rehabilitation, a secondary prevention programme, aims to increase physical activity levels in this population from a reported low baseline. This trial will investigate the effectiveness and implementation of a very brief physical activity intervention, comparing different frequencies of physical activity measurement by cardiac rehabilitation clinicians. The Measure It! intervention (<5 min) includes a self-report and objective measure of physical activity (steps) plus very brief physical activity advice. METHODS AND ANALYSIS: This type 1 hybrid effectiveness-implementation study will use a two-arm multicentre assessor-blind randomised trial design. Insufficiently active (<150 min of moderate-to-vigorous physical activity per week) cardiac rehabilitation attendees with CHD (18+ years) will be recruited from five phase II cardiac rehabilitation centres (n=190). Patients will be randomised (1:1) to five physical activity measurements or two physical activity measurements in total over 24 weeks. The primary effectiveness outcome is accelerometer daily minutes of moderate-to-vigorous intensity physical activity at 24 weeks. Secondary effectiveness outcomes include body mass index, waist circumference and quality-of-life. An understanding of multilevel contextual factors that influence implementation, and antecedent outcomes to implementation of the intervention (eg, feasibility and acceptability), will be obtained using semistructured interviews and other data sources. Linear mixed-effects models will be used to analyse effectiveness outcomes. Qualitative data will be thematically analysed inductively and deductively using framework analysis, with the framework guided by the Consolidated Framework for Implementation Research and Theoretical Domains Framework. ETHICS AND DISSEMINATION: The study has ethical approval (University of Canberra (ID 11836), Calvary Bruce Public Hospital (ID 14-2022) and the Greater Western Area (ID 2022/ETH01381) Human Research Ethics Committees). Results will be disseminated in multiple formats for consumer, public and clinical audiences. TRIAL REGISTRATION NUMBER: ACTRN12622001187730p.

Influence of sex on efficacy of exercise training for patients with symptomatic atrial fibrillation: insights from the ACTIVE-AF randomized controlled trial.

AIMS: Exercise training reduces recurrence of arrhythmia and symptom severity amongst patients with symptomatic, non-permanent atrial fibrillation (AF). However, there is little evidence on whether this effect is modified by patient sex. In a sub-analysis from the ACTIVE-AF (A Lifestyle-based, PhysiCal AcTIVity IntErvention for Patients With Symptomatic Atrial Fibrillation) randomized controlled trial, we compared the effects of exercise training on AF recurrence and symptom severity between men and women. METHODS AND RESULTS: The ACTIVE-AF study randomized 120 patients (69 men, 51 women) with paroxysmal or persistent AF to receive an exercise intervention combining supervised and home-based aerobic exercise over 6 months or to continue standard medical care. Patients were followed over a 12-month period. The co-primary outcomes were recurrence of AF, off anti-arrhythmic medications and without catheter ablation, and AF symptom severity scores. By 12 months, recurrence of AF was observed in 50 (73%) men and 34 (67%) women. In an intention-to-treat analysis, there was a between-group difference in favour of the exercise group for both men [hazard ratio (HR) 0.52, 95% confidence interval (CI): 0.29-0.91, P = 0.022] and women (HR 0.47, 95% CI: 0.23-0.95, P = 0.035). At 12 months, symptom severity scores were lower in the exercise group compared with controls amongst women but not for men. CONCLUSION: An exercise-based intervention reduced arrhythmia recurrence for both men and women with symptomatic AF. Symptom severity was reduced with exercise in women at 12 months. No difference was observed in symptom severity for men. REGISTRATION: Australia and New Zealand Clinical Trials Registry: ACTRN12615000734561.

This analysis examined the potential benefit of exercise training on arrhythmia recurrence and symptom severity amongst men and women with symptomatic atrial fibrillation enrolled in a randomized controlled trial of exercise and physical activity intervention compared with standard medical care. Previous studies have not provided evidence on whether men and women might benefit from exercise training to a similar degree. Our findings highlight the following key points: Both men and women in our study experienced fewer arrhythmia recurrences with exercise training compared with men and women in standard medical care.Exercise reduced arrhythmia symptoms in women, but we did not find any evidence of a reduction in symptoms amongst men.

A Clinical Guide for Assessment and Prescription of Exercise and Physical Activity in Cardiac Rehabilitation. A CSANZ Position Statement.

Patients with cardiovascular disease benefit from cardiac rehabilitation, which includes structured exercise and physical activity as core components. This position statement provides pragmatic, evidence-based guidance for the assessment and prescription of exercise and physical activity for cardiac rehabilitation clinicians, recognising the latest international guidelines, scientific evidence and the increasing use of technology and virtual delivery methods. The patient-centred assessment and prescription of aerobic exercise, resistance exercise and physical activity have been addressed, including progression and safety considerations.

An Exercise and Physical Activity Program in Patients With Atrial Fibrillation: The ACTIVE-AF Randomized Controlled Trial.

BACKGROUND: There are limited data on the effect of exercise interventions on atrial fibrillation (AF) recurrence and symptoms. OBJECTIVES: The aim of this study was to determine the efficacy of an exercise and physical activity intervention on AF burden and symptoms among patients with symptomatic AF. METHODS: This prospective, randomized controlled trial included 120 patients with paroxysmal or persistent, symptomatic AF, randomized 1:1 to receive an exercise intervention, combining home and supervised aerobic exercise over 6 months, or to receive usual care. The coprimary outcomes were: 1) AF recurrence, off antiarrhythmic medications and without catheter ablation; and 2) symptom severity assessed by using a validated questionnaire. RESULTS: By 12 months, freedom from AF was achieved in 24 (40%) of 60 patients in the exercise group and 12 (20%) of 60 patients in the control group (HR: 0.50: 95% CI: 0.33 to 0.78). At 6 months, AF symptom severity was lower in the exercise group compared with the control group (mean difference -2.3; 95% CI: -4.3 to -0.2; P = 0.033). This difference persisted at 12 months (-2.3; 95% CI: -4.5 to -0.1; P = 0.041). Total symptom burden was lower at 6 months in the exercise group but not at 12 months. Peak oxygen consumption was increased in the exercise group at both 6 and 12 months. There were no between-group differences in cardiac structure or function, body mass index, or blood pressure. CONCLUSIONS: Participation in an exercise-based intervention over 6 months reduced arrhythmia recurrence and improved symptom severity among patients with AF. (A Lifestyle-based, PhysiCal AcTIVity IntErvention for Patients With Symptomatic Atrial Fibrillation [the ACTIVE-AF Study]; ACTRN12615000734561).

Impact of Early COVID-19 Waves on Cardiac Rehabilitation Delivery in Australia: A National Survey.

BACKGROUND: The novel coronavirus disease of 2019 (COVID-19) pandemic significantly disrupted health care, especially outpatient services such as cardiac rehabilitation (CR). We investigated the impact of early COVID-19 waves on the delivery of Australian CR programs, comparing this time period with usual practice prior to the pandemic (2019) and current practice (2021) once the early waves had subsided. Specifically, we aimed to understand how the delivery of programs during COVID-19 compared to usual practice. METHODS: An anonymous online cross-sectional survey of Australian CR program staff was conducted, comprising three sections: program and respondent characteristics, COVID-19 impact on program delivery, and barriers to, and enablers of, program delivery. Respondents were asked to consider three key timepoints: 1) Pre-COVID-19 (i.e. usual practice in 2019), 2) Early COVID-19 waves (March-December 2020), and 3) Currently, at time of survey completion post early COVID-19 waves (May-July 2021). RESULTS: Of the 314 Australian CR programs, 115 responses were received, of which 105 had complete data, representing a 33% response rate. All states and territories were represented. During early COVID-19 waves programs had periods of closure (40%) or reduced delivery (70%). The majority of programs reported decreased CR referrals (51.5%) and decreased participation (77.5%). The two core components of CR-exercise and education-were significantly impacted during early COVID-19 waves, affecting both the number and duration of sessions provided. Exercise session duration did not return to pre-pandemic levels (53.5 min compared to 57.7 min, p=0.02). The majority of respondents (77%) reported their CR program was inferior in quality to pre-pandemic and more organisational support was required across information technology, staffing, administration and staff emotional and social support. CONCLUSION: Australian CR programs underwent significant change during the early COVID-19 waves, consistent with international CR reports. Fewer patients were referred and attended CR and those who did attend received a lower dose of exercise and education. It will be important to continue to monitor the long-term impacts of the COVID-19 pandemic to ensure CR programs return to pre-pandemic functioning and continue to deliver services in line with best practice and evidence-based recommendations.

Use of heart rate for guiding exercise training in patients with atrial fibrillation.

BACKGROUND: Heart rate reserve (HRR) is used to guide exercise training in patients with cardiovascular disease, primarily as a surrogate for oxygen uptake reserve (VO2R) as a marker of metabolic demand. However, the relationship between HRR and VO2R in patients with atrial fibrillation (AF) is not well described. We aimed to assess the validity of HRR as a surrogate for VO2R to guide exercise intensity in AF patients. METHODS: One hundred one patients with non-permanent AF undertaking a cardiopulmonary exercise test (CPET) were prospectively enrolled. HR and VO2 values were recorded throughout exercise to determine HRR and VO2R at each workload. Linear regression was used to calculate the slope and y-intercept for HRR versus VO2R with an equivalent slope defined as 1 and y-intercept of 0. The impact of rhythm during exercise, beta blockers and chronotropic incompetence (CI) on the HRR-VO2R relationship was also assessed. RESULTS: The slope of HRR-VO2R was 0.79±0.4, indicating a significant difference from an assumed slope of 1.0 (mean difference: -0.21, 95% CI: -0.30 to -0.12, P<0.001). The mean y-intercept slope was 20.1±41.6, differing significantly from 0 (mean difference: 20.1, 95% CI: 11.9-28.3, P<0.001). The presence of AF during CPET, beta-blockers or chronotropic incompetence did not independently alter the association between VO2R and HRR. CONCLUSIONS: HRR is not equivalent to VO2R in AF patients. There was no significant effect of rhythm status, chronotropic incompetence or beta-blockers on this relationship. These findings highlight that the HR prescription of exercise intensity in AF patients should be guided by an individualised HRR-VO2R relationship.

Factors Contributing to Exercise Intolerance in Patients With Atrial Fibrillation.

BACKGROUND: Reduced exercise capacity and exercise intolerance are commonly reported by individuals with atrial fibrillation (AF). Our objectives were to evaluate the contributing factors to reduced exercise capacity and describe the association between subjective measures of exercise intolerance versus objective measures of exercise capacity. METHODS: Two hundred and three (203) patients with non-permanent AF and preserved ejection fraction undergoing cardiopulmonary exercise testing (CPET) were recruited. Clinical characteristics, AF-symptom evaluation, and transthoracic echocardiography measures were collected. Peak oxygen consumption (VO2peak) was calculated during CPET as an objective measure of exercise capacity. We assessed the impact of 16 pre-defined clinical features, comorbidities and cardiac functional parameters on VO2peak. RESULTS: Across this cohort (Age 66±11 years, 40.4% female and 32% in AF), the mean VO2peak was 20.3±6.3 mL/kg/min. 24.9% of patients had a VO2peak considered low (<16 mL/kg/min). In multivariable analysis, echocardiography-derived estimates of elevated left ventricular (LV) filling pressure (E/E') and reduced chronotropic index were significantly associated with lower VO2peak. The presence of AF at the time of testing was not significantly associated with VO2peak but was associated with elevated minute ventilation to carbon dioxide production indicating impaired ventilatory efficiency. There was a poor association between VO2peak and subjectively reported exercise intolerance and exertional dyspnoea. CONCLUSION: Reduced exercise capacity in AF patients is associated with elevated LV filling pressure and reduced chronotropic response rather than rhythm status. Subjectively reported exercise intolerance is not a sensitive assessment of reduced exercise capacity. These findings have important implications for understanding reduced exercise capacity amongst AF patients and the approach to management in this cohort. (ACTRN12619001343190).

Self-reported physical activity and atrial fibrillation risk: A systematic review and meta-analysis.

BACKGROUND: Although physical activity (PA) is an important component of cardiovascular disease prevention and treatment, its role in atrial fibrillation (AF) risk is less well established. OBJECTIVE: The purpose of this study was to systematically summarize the evidence pertaining to the relationship of PA and risk of AF. METHODS: We searched the PubMed and Embase databases for prospective cohort studies reporting the risk of AF associated with a specific PA volume through March 2020. From each study, we extracted the risk associated with a given PA level, in comparison with insufficiently active ("inactive") individuals. The reported risk was normalized to metabolic equivalent of task (MET)-minutes per week. A random-effects meta-analysis was used to compare AF risk between those who met and those who did not meet PA recommendations (450 MET-minutes per week), and a dose-response analysis between the level of PA and the risk of AF was performed. RESULTS: Fifteen studies reporting data from 1,464,539 individuals (median age 55.3 years; 51.7% female) were included. Individuals achieving guideline-recommended level of PA had a significantly lower risk of AF (hazard ratio 0.94; 95% confidence interval 0.90-0.97; P = .001). Dose-response analysis showed that PA levels up to 1900 MET-minutes per week were associated with a lower risk of AF, with less certainty beyond that level. CONCLUSION: PA at guideline-recommended levels and above are associated with a significantly lower AF risk. However, at 2000 MET-minutes per week and beyond, the benefit is less clear.

Association between physical activity and risk of incident arrhythmias in 402 406 individuals: evidence from the UK Biobank cohort.

AIMS: Physical activity reduces cardiovascular disease burden and mortality, although its relationship with cardiac arrhythmias is less certain. The aim of this study was to assess the association between self-reported physical activity and atrial fibrillation (AF), ventricular arrhythmias and bradyarrhythmias, across the UK Biobank cohort. METHODS AND RESULTS: We included 402 406 individuals (52.5% female), aged 40-69 years, with over 2.8 million person-years of follow-up who underwent self-reported physical activity assessment computed in metabolic equivalent-minutes per week (MET-min/wk) at baseline, detailed physical assessment and medical history evaluation. Arrhythmia episodes were diagnosed through hospital admissions and death reports. Incident AF risk was lower amongst physically active participants, with a more pronounced reduction amongst female participants [hazard ratio (HR) for 1500 vs. 0 MET-min/wk: 0.85, 95% confidence interval (CI) 0.74-0.98] than males (HR for 1500 vs. 0 MET-min/wk: 0.90, 95% CI 0.82-1.0). Similarly, we observed a significantly lower risk of ventricular arrhythmias amongst physically active participants (HR for 1500 MET-min/wk 0.78, 95% CI 0.64-0.96) that remained relatively stable over a broad range of physical activity levels between 0 and 2500 MET-min/wk. A lower AF risk amongst female participants who engaged in moderate levels of vigorous physical activity was observed (up to 2500 MET-min/wk). Vigorous physical activity was also associated with reduced ventricular arrhythmia risk. Total or vigorous physical activity was not associated with bradyarrhythmias. CONCLUSION: The risk of AF and ventricular arrhythmias is lower amongst physically active individuals. These findings provide observational support that physical activity is associated with reduced risk of atrial and ventricular arrhythmias.

Exercise and Atrial Fibrillation: Prevention or Causation?

Regular exercise contributes to improved cardiovascular health and reduced cardiovascular mortality. Previous studies have shown that regular physical activity and high cardiorespiratory fitness both contribute to a reduction in incident atrial fibrillation (AF). However, the risk of AF appears to be paradoxically increased by participation in endurance exercise. Although the mechanisms are not well understood, exercise-induced changes in autonomic tone alongside the development of an arrhythmogenic atrial substrate, appear to contribute to an excess of AF amongst athletes, despite an overall reduction in cardiovascular disease incidence. This review will (i) summarise the evidence showing that regular physical activity and exercise reduces AF incidence, (ii) review the evidence that supports an increase in AF risk by regular endurance exercise, and (iii) discuss the mechanisms and risk factors that may contribute to AF susceptibility amongst otherwise healthy athletes.

Atrial remodeling and ectopic burden in recreational athletes: Implications for risk of atrial fibrillation.

BACKGROUND: Atrial remodeling, vagal tone, and atrial ectopic triggers are suggested to contribute to increased incidence of atrial fibrillation (AF) in endurance athletes. How these parameters change with increased lifetime training hours is debated. HYPOTHESIS: Atrial remodeling occurs in proportion to total training history, thus contributing to elevated risk of AF. METHODS: We recruited 99 recreational endurance athletes, subsequently grouped according to lifetime training hours, to undergo evaluation of atrial size, autonomic modulation, and atrial ectopy. Athletes were grouped by self-reported lifetime training hours: low (<3000 h), medium (3000-6000 h), and high (>6000 h). Left atrial (LA) volume, left ventricular (LV) dimensions, and LV systolic and diastolic function were assessed by echocardiography. We used 48-hour ambulatory electrocardiographic monitoring to determine heart rate, heart rate variability, premature atrial contractions, and premature ventricular contractions. RESULTS: LA volume was significantly greater in the high (+5.1 mL/m2 , 95% CI: 1.3-8.9) and medium (+4.2 mL/m2 , 95% CI: 0.2-8.1) groups, compared with the low group. LA dilation was observed in 19.4%, 12.9%, and 0% of the high, medium, and low groups, respectively (P = 0.05). No differences were observed between groups for measures of LV dimensions or function. Minimum heart rate, parasympathetic tone expressed using heart rate variability indices, and premature atrial contraction and premature ventricular contraction frequencies did not differ between groups. CONCLUSIONS: In recreational endurance athletes, increased lifetime training is associated with LA dilation in the absence of increased vagal parameters or atrial ectopy, which may promote incidence of AF in this cohort.