Today, I review and link to Today, I review and link to The European Society of Cardiology‘s 2024 Guidelines on Atrial Fibrillation, 3. Definitions and clinical impact.
All that follows is from the above resource.
3.1. Definition and classification of AF
Atrial fibrillation is one of the most common heart rhythm disorders. A supraventricular arrhythmia with uncoordinated atrial activation, AF results in a loss of effective atrial contraction (see Supplementary data online for pathophysiology). AF is reflected on the surface electrocardiogram (ECG) by the absence of discernible and regular P waves, and irregular activation of the ventricles. This results in no specific pattern to RR intervals, in the absence of an atrioventricular block. The definition of AF by temporal pattern is presented in Table 5. It should be noted that these categories reflect observed episodes of AF and do not suggest the underlying pathophysiological process. Some patients may progress consecutively through these categories, while others may need periodic reclassification due to their individual clinical status. Over time, some patients with AF develop atrial and ventricular damage, which can make attempts at rhythm control futile. For this reason, or when patients and physicians make a joint decision for rate control, AF is classified as permanent (the most common ‘type’ of AF in historical registries).1 Despite many limitations, this task force have retained this temporal approach because most trials in patients with AF have used these definitions. Classifying AF by underlying drivers could inform management, but the evidence in support of the clinical use of such classification is currently lacking.
Table 5 Definitions and classifications for the temporal pattern of AF
Temporal classification Definition First-diagnosed AF AF that has not been diagnosed before, regardless of symptom status, temporal pattern, or duration. Paroxysmal AF AF which terminates spontaneously within 7 days or with the assistance of an intervention. Evidence suggests that most self-terminating paroxysms last <48 h.2 Persistent AF AF episodes which are not self-terminating. Many intervention trials have used 7 days as a cut-off for defining persistent AF.3,4 Long-standing persistent AF is arbitrarily defined as continuous AF of at least 12 months’ duration but where rhythm control is still a treatment option in selected patients, distinguishing it from permanent AF. Permanent AF AF for which no further attempts at restoration of sinus rhythm are planned, after a shared decision between the patient and physician.
AF, atrial fibrillation.
© ESC 2024
Several other classifications have been applied to patients with AF, many of which have limited evidence to support them. The definition of AF is a developing field and ongoing research may allow for pathology-based strategies that could facilitate personalized management in the future. Table 6 presents some commonly used concepts in current clinical practice. Due to the lack of supporting evidence (particularly for the time periods stated), this task force have edited and updated these definitions by consensus.
Table 6 Other clinical concepts relevant to AF
Clinical concept Definition Clinical AF Symptomatic or asymptomatic AF that is clearly documented by an ECG (12-lead ECG or other ECG devices). The minimum duration to establish the diagnosis of clinical AF for ambulatory ECG is not clear and depends on the clinical context. Periods of 30 s or more may indicate clinical concern, and trigger further monitoring or risk stratification for thromboembolism. Device-detected subclinical AF Device-detected subclinical AF refers to asymptomatic episodes of AF detected on continuous monitoring devices. These devices include implanted cardiac electronic devices, for which most atrial high-rate episodesa may be AF, as well as consumer-based wearable monitors. Confirmation is needed by a competent professional reviewing intracardiac electrograms or an ECG-recorded rhythm.5,6 Device-detected subclinical AF is a predictor of future clinical AF.7 AF burden The overall time spent in AF during a clearly specified and reported period of monitoring, expressed as a percentage of time. Recent-onset AF There is accumulating data on the value of the term recent-onset AF in decision-making for acute pharmacological or electrical cardioversion of AF. The cut-off time interval to define this entity has not yet been established.8–10 Trigger-induced AF New AF episode in close proximity to a precipitating and potentially reversible factor.11–14 Early AF The time since diagnosis that qualifies for early AF is dissociated from any underlying atrial cardiomyopathy and is not well defined, broadly ranging from 3 to 24 months.15–17 The definition of early AF also does not necessarily determine early timing of intervention. Self-terminating AF Paroxysmal AF which terminates spontaneously.2 This definition may be of value for decisions on acute rhythm control taken jointly by the patient and healthcare provider. Non-self-terminating AF Atrial fibrillation which does not terminate spontaneously and, if needed, termination can be achieved only with an intervention. Atrial cardiomyopathy A combination of structural, electrical, or functional changes in the atria that leads to clinical impact (e.g. progression/recurrence of AF, limited effectiveness of AF therapy, and/or development of heart failure).18,19 Atrial cardiomyopathy includes inflammatory and prothrombotic remodelling of the atria, neurohormonal activation (thereby affecting the ventricles), and fibrosis of myocardial tissue.20
AF, atrial fibrillation; b.p.m., beats per minute; ECG, electrocardiogram.
aAtrial high-rate episodes are defined as episodes generally lasting more than 5 min with an atrial lead rate ≥170 b.p.m.,7,21–24 detected by implanted cardiac devices that allow for automated continuous monitoring and storage of atrial rhythm. Atrial high-rate episodes need to be visually inspected because some may be electrical artefacts or false positives.
© ESC 20243.2. Diagnostic criteria for AF
In many patients, the diagnosis of AF is straightforward, e.g. typical symptoms associated with characteristic features on a standard 12-lead ECG that indicate the need for AF management. Diagnosis becomes more challenging in the context of asymptomatic episodes or AF detected on longer-term monitoring devices, particularly those that do not provide an ECG (see Section 10). To guard against inappropriate diagnosis of AF, this task force continues to recommend that ECG documentation is required to initiate risk stratification and AF management. In current practice, ECG confirmation can include multiple options: not only where AF persists across a standard 12-lead ECG, but also single- and multiple-lead devices that provide an ECG (see Supplementary data online, Additional Evidence Table S1). This does not include non-ECG wearables and other devices that typically use photoplethysmography. Note that many pivotal AF trials required two or more ECGs documenting AF, or an established AF diagnosis before randomization.25–29 The time period of AF required for diagnosis on monitoring devices is not clear cut. A standard 12-lead ECG measures 10 s, while 30 s or more on single-lead or multiple-lead ECG devices has generally been the consensus opinion, albeit with limited evidence.
Recommendation Table 1 Recommendations for the diagnosis of AF (see also Evidence Table 1)
3.3. Symptoms attributable to AF
Symptoms related to episodes of AF are variable and broad, and not just typical palpitations (Figure 1). Asymptomatic episodes of AF can occur,30 although 90% of patients with AF describe symptoms with variable severity.31 Even in symptomatic patients, some episodes of AF may remain asymptomatic.32,33 The presence or absence of symptoms is not related to incident stroke, systemic embolism, or mortality.34 However, symptoms do impact on patient quality of life.35,36 Cardiac-specific AF symptoms such as palpitations are less common than non-specific symptoms such as fatigue, but they significantly impair quality of life.36,37 Although women are often underrepresented in clinical trials of AF,38–40 the available literature suggests that women with AF appear to be more symptomatic and have poorer quality of life.41,42 Patients with AF report a higher burden of anxiety and severity of depression (odds ratio [OR], 1.08; 95% confidence interval [CI], 1.02–1.15; P = .009) as compared with the general population,43,44 with higher prevalence of these symptoms in women with AF.45
Figure 1Impacts and outcomes associated with clinical AF. AF, atrial fibrillation.
Assessment of AF-related symptoms should be recorded initially, after a change in treatment, or before and after intervention. The modified European Heart Rhythm Association score (mEHRA) symptom classification (Table 7) is similar to the New York Heart Association (NYHA) functional class for heart failure. It correlates with quality of life scores in clinical trials, is associated with clinical progress and events, and may be a valuable starting point in routine practice to assess the burden and impact of symptoms together with the patient.46–48 Note that symptoms may also relate to associated comorbidities and not just the AF component. The patient-related effects of symptoms from AF over time can alternatively be evaluated using patient-reported outcome measures (see Section 8.4).
Table 7 The modified European Heart Rhythm Association (mEHRA) symptom classification
Score Symptoms Description 1 None AF does not cause any symptoms 2a Mild Normal daily activity not affected by symptoms related to AF 2b Moderate Normal daily activity not affected by symptoms related to AF, but patient troubled by symptoms 3 Severe Normal daily activity affected by symptoms related to AF 4 Disabling Normal daily activity discontinued AF, atrial fibrillation.
© ESC 2024Recommendation Table 2 Recommendations for symptom evaluation in patients with AF (see also Evidence Table 2)3.4. Diagnostic evaluation of new AF
All patients with AF should be offered a comprehensive diagnostic assessment and review of medical history to identify risk factors and/or comorbidities needing active treatment. Table 8 displays the essential diagnostic work-up for a patient with AF.
Table 8 Diagnostic work-up for patients with AF
All patients Selected patients
Medical history to determine AF pattern, relevant family history, and comorbidities, and to assess risk factors for thromboembolism and bleeding
Ambulatory ECG monitoring for assessing AF burden and ventricular rate control
Exercise ECG to evaluate rate control or effects of class IC antiarrhythmic drugs
12-lead ECG
Further blood tests for investigation of cardiovascular disease and refinement of stroke/bleeding risk (e.g. NT-proBNP, troponin)
Assess symptoms and functional impairment
Transoesophageal echocardiography for left atrial thrombus and valvular disease assessment
Collect generic or AF-specific patient-reported outcome measures
Coronary CT, angiography, or ischaemia imaging for suspected CAD
Blood tests (full blood count, kidney function, serum electrolytes, liver function, glucose/HbA1c, and thyroid function)
CMR for evaluation of atrial and ventricular cardiomyopathies, and to plan interventional procedures
Transthoracic echocardiography where this will guide AF-CARE management decisions
Brain imaging and cognitive function assessment for cerebrovascular disease and dementia risk
AF, atrial fibrillation; AF-CARE, atrial fibrillation—[C] Comorbidity and risk factor management, [A] Avoid stroke and thromboembolism, [R] Reduce symptoms by rate and rhythm control, [E] Evaluation and dynamic reassessment; CAD, coronary artery disease; CMR, cardiac magnetic resonance; CT, computed tomography; CTA, computed tomography angiography; ECG, electrocardiogram; HbA1c, glycated haemoglobin; NT-proBNP, N-terminal pro-B-type natriuretic peptide.
© ESC 2024A 12-lead ECG is warranted in all AF patients to confirm rhythm, determine ventricular rate, and look for signs of structural heart disease, conduction defects, or ischaemia.56 Blood tests should be carried out (kidney function, serum electrolytes, liver function, full blood count, glucose/glycated haemoglobin [HbA1c], and thyroid tests) to detect any concomitant conditions that may exacerbate AF or increase the risk of bleeding and/or thromboembolism.57,58
Other investigations will depend on individualized assessment and the planned treatment strategy.59–65 A transthoracic echocardiogram (TTE) should be carried out in the initial work-up, where this will guide management decisions, or in patients where there is a change in cardiovascular signs or symptoms. The task force recognizes that accessibility to TTE might be limited or delayed in the primary care setting, but this should not delay initiation of oral anticoagulation (OAC) or other components of AF-CARE where indicated.66 Further details on TTE and reassessment (e.g. if elevated heart rate limits diagnostic imaging, or where there is a change in clinical status) are presented in Section 8.3. Additional imaging using different modalities may be required to assist with comorbidity and AF-related management (see Supplementary data online, Figure S1).
Recommendation Table 3 Recommendations for diagnostic evaluation in patients with new AF (see also Evidence Table 3)
3.5. Adverse events associated with AF
Figure 1 Impacts and outcomes associated with clinical AF. AF, atrial fibrillation.Atrial fibrillation is associated with a range of serious adverse events (Figure 1) (see Supplementary data online, Additional Evidence Table S2). Patients with AF also have high rates of hospitalization and complications from coexisting medical conditions. The most common non-fatal outcome in those with AF is heart failure, occurring in around half of patients over time. Patients with AF have a four- to five-fold increase in the relative risk (RR) of heart failure compared with those without AF, as demonstrated in two meta-analyses (RR, 4.62; 95% CI, 3.13–6.83 and RR, 4.99; 95% CI, 3.0–8.22).68,69 The next most common adverse impacts from AF are ischaemic stroke (RR, 2.3; 95% CI, 1.84–2.94), ischaemic heart disease (RR, 1.61; 95% CI, 1.38–1.87), and other thromboembolic events.69–71 The latter typically include arterial thromboembolic events (preferred to the term systemic), although venous thromboembolism is also associated with AF.72,73 Patients with AF also have an increased risk of cognitive impairment (adjusted hazard ratio [HR], 1.39; 95% CI, 1.25–1.53)74 and dementia (OR, 1.6; 95% CI, 1.3–2.0).75–77 It should be noted that most of the observational studies on adverse events have a mix of patients taking and not taking OAC. When carefully controlling for the confounding effects of stroke, comorbidities, and OAC, AF exposure was still significantly associated with vascular dementia (HR, 1.68; 95% CI, 1.33–2.12; P < .001), but not Alzheimer’s disease (HR, 0.85; 95% CI, 0.70–1.03; P = .09).78
Hospital admission rates due to AF vary widely depending on the population studied, and may be skewed by selection bias. In a Dutch RCT including first-diagnosed AF patients (mean age 64 years), cardiovascular hospitalization rates were 7.0% to 9.4% per year.79 An Australian study identified 473 501 hospitalizations for AF during 15 years of follow-up (300 million person-years), with a relative increase in AF hospitalizations of 203% over the study period, in contrast to an increase for all hospitalizations of 71%. The age-specific incidence of hospital admission increased particularly in the older age groups.80
Atrial fibrillation is also associated with increased mortality. In 2017, AF contributed to over 250 000 deaths globally, with an age-standardized mortality rate of 4.0 per 100 000 people (95% uncertainty interval 3.9–4.2).81 The most frequent cause of death in patients with AF is heart failure related,70 with complex relationships to cardiovascular and non-cardiovascular disease.82 There is up to a two-fold increased risk of all-cause mortality (RR, 1.95; 95% CI, 1.50–2.54),68 and cardiovascular mortality (RR, 2.03; 95% CI, 1.79–2.30)69 in AF compared with sinus rhythm. Even in the absence of major thromboembolic risk factors, the incidence of death is 15.5 per 1000 person-years in those with AF exposure, compared with 9.4 per 1000 person-years without (adjusted HR, 1.44; 95% CI, 1.38–1.50; P < .001).78 Patients with OAC-related bleeding have higher mortality, including both minor and major bleeding (as defined by the International Society on Thrombosis and Haemostasis scale).83 Despite OAC, patients with AF remain at high residual risk of death, highlighting the importance of attention to concomitant disease.84
84 Pokorney SD, et al. Cause of death and predictors of all-cause mortality in anticoagulated patients with nonvalvular atrial fibrillation: data from ROCKET AF. J Am Heart Assoc 2016; 5: e002197 10.1161/JAHA.115.002197 Google Scholar
3.6. Atrial flutter
Atrial flutter (AFL) is the among the most common atrial tachyarrhythmias, with an overall incidence rate of 88 per 100 000 person-years, rising to 317 per 100 000 person-years in people over 50 years of age.85 Risk factors for AFL and AF are similar, and more than half of all patients with AFL will develop AF.85 Observational studies suggest that thromboembolic risk is elevated in AFL.86 In direct comparison of AFL with AF, some studies suggest a similar risk of stroke and others a lower risk in AFL,87–90 possibly due to different comorbidity burdens and the impact of confounders such as AFL/AF ablation and anticoagulation (more frequently stopped in AFL).91
