Diagnosis and diagnostic recommendations of atrial fibrillation

Atrial fibrillation diagnosis can be challenging, but ECG monitoring is the foundation of assessment.

An irregular pulse should raise a suspicion of AF: the sensitivity and specificity of pulse rate for AF is 94% and 72% respectively.19,32 Clinical presentation (Table 5) may indicate the type of AF, although about a third of AF episodes are asymptomatic.5,19

Table 5. Presentation of different clinical types of atrial fibrillation.5

Presentation of different clinical types of atrial fibrillation

 So, an ECG (figure 9) is the gold-standard method to diagnose AF.19 In addition, all AF patients should undergo a comprehensive evaluation, including accurate history, clinical examination and assessment of co-morbidities and risk factors.5

Electrocardiogram showing normal sinus rhythm, atrial fibrillation and differential diagnoses

Figure 9. Electrocardiogram showing normal sinus rhythm, atrial fibrillation and differential diagnoses.

Typically, ECGs of AF typically do not show distinct P wave.6,32 Rather the electrical activity is disorderly (fibrillatory) with irregular R-R intervals.6,32 Heartbeat is erratic and rapid, typically 90–170 beats per minute, reflecting the irregular ventricular activation. Unless the patient has other cardiac conduction disorders, the QRS complex tends to be narrow.32 Clinicians should consider Holter monitoring (using a portable device for 24 to 48 hour cardiac monitoring) in patients presenting with palpitations.8

Diagnostic recommendations

As AF can develop for the first time after a stroke, guidelines published by the European Society for Cardiology (ESC) and the European Heart Rhythm Association (EHRA) suggest considering prolonged ECG monitoring (using non-invasive ECG monitors or implanted loop recorders) in all survivors of an ischaemic stroke without documented AF. Patients with TIA or ischaemic stroke should be screened for AF using short-term ECG recording and continuous monitoring for at least 72 hours.5 Continuous ECG monitoring would identify AF in about 1 in 20 patients presenting with acute stroke.8,20

In addition, the ESC/EHRA guidelines recommend:5

  • opportunistic AF screening by measuring the pulse or from an ECG rhythm strip in patients older than 65 years of age 
  • regularly interrogate pacemakers and implantable cardioverter defibrillators for atrial high rate episodes; if present, patients should undergo additions ECG monitoring to detect AF
  • considering systematic ECG AF screening in patients older than 75 years of age or at high stroke risk
  • using transthoracic echocardiography, which can assess valvular heart disease and exclude intracardiac thrombi, to guide management with early cardioversion or catheter ablation 
  • considering long-term ECG monitoring to assess rate control in people with symptomatic AF
  • considering long-term ECG monitoring to correlate symptoms with AF episodes and differentiate proximal and persistent AF


The next section details under-diagnosis of atrial fibrillation

Other sections to further your understanding in the disease awareness section include:

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