Atrial fibrillation (AF) is the most common sustained heart rhythm disorder in adults, and its prevalence rises sharply with age. Many people with AF have no symptoms, yet AF increases the risk of stroke around five-fold. Nurses detect AF every day, often by simply feeling a pulse. Knowing what to do next protects patients from strokes and heart failure.
What happens in AF
Instead of a coordinated contraction, the atria quiver chaotically. Impulses reach the ventricles irregularly, producing an irregularly irregular pulse. Because the atria don’t empty properly, blood can pool, particularly in the left atrial appendage, and form clots that may travel to the brain.
Types
- Paroxysmal: comes and goes, usually stopping within 7 days.
- Persistent: lasts more than 7 days.
- Permanent: accepted long term; no further attempts to restore normal rhythm.
Causes and triggers
- Hypertension, coronary heart disease, heart failure, valve disease (including rheumatic heart disease, still common in parts of Africa and Asia).
- Infection and sepsis, especially pneumonia.
- Thyroid overactivity.
- Alcohol (“holiday heart”), caffeine excess, stimulants.
- After surgery, especially cardiac and thoracic surgery.
- Electrolyte imbalances (low potassium or magnesium), pulmonary embolism, obesity, sleep apnoea.
Detecting AF
- Feel the pulse manually for a full 60 seconds. Automatic BP machines and oximeters may give misleading rates in AF.
- Symptoms may include palpitations, breathlessness, dizziness, fatigue, chest discomfort, or none at all.
- Confirm with a 12-lead ECG: irregularly irregular RR intervals, no P waves, sometimes a wavy baseline. See our ECG basics guide.
- Note the ventricular rate: “fast AF” typically means a rate above 100–110.
Fast AF on the ward: what to do
- A–E assessment. Check for adverse features: shock (low BP, pale, clammy), syncope, chest pain (myocardial ischaemia), or heart failure. If present, this is an emergency: call for urgent help; synchronised cardioversion may be needed.
- 12-lead ECG and cardiac monitoring.
- Look for and treat triggers: sepsis, dehydration, pain, low potassium/magnesium, alcohol withdrawal, thyroid problems.
- Bloods: electrolytes (including magnesium), thyroid function, FBC, infection markers as advised.
- Administer rate-control medicines as prescribed and monitor heart rate and BP closely.
Rate control vs rhythm control
- Rate control: slowing the ventricular rate with beta-blockers (e.g. bisoprolol), rate-limiting calcium channel blockers (e.g. diltiazem), or digoxin (often in heart failure or sedentary patients). Check heart rate and BP before giving; hold and escalate if the pulse is low as per prescription parameters.
- Rhythm control: restoring and maintaining normal sinus rhythm with electrical cardioversion, antiarrhythmic drugs (e.g. amiodarone, flecainide), or catheter ablation. Usually considered for new-onset AF, symptomatic patients, or when rate control fails.
Stroke prevention: anticoagulation
Stroke risk is commonly assessed using the CHA₂DS₂-VASc score (Congestive heart failure, Hypertension, Age ≥75 [2 points], Diabetes, prior Stroke/TIA [2 points], Vascular disease, Age 65–74, Sex category female). Some newer guidelines use a version without the sex criterion. Higher scores mean higher stroke risk and usually an indication for anticoagulation. Bleeding risk is also considered, though it doesn’t by itself rule out treatment.
- DOACs (apixaban, rivaroxaban, edoxaban, dabigatran) are now usually preferred.
- Warfarin is used in some cases, such as moderate-to-severe mitral stenosis or mechanical heart valves, and where DOACs aren’t available or affordable.
- Aspirin is not recommended for stroke prevention in AF.
See our detailed anticoagulants guide.
Patient education
- What AF is, and why stroke prevention matters even if they feel well.
- How to take anticoagulants, what to do about missed doses, and the importance of not stopping without advice.
- Bleeding signs to report: black stools, blood in urine, prolonged nosebleeds, severe headache.
- Recognising stroke: BE FAST.
- Lifestyle: limit alcohol, manage blood pressure and weight, treat sleep apnoea, stop smoking, regular activity.
- How to check their own pulse.
Before cardioversion
If AF has lasted more than 48 hours (or the duration is unknown), cardioversion carries a risk of stroke unless the patient has been adequately anticoagulated for several weeks or a clot has been ruled out with transoesophageal echocardiography. Nurses should check anticoagulation status and fasting, and monitor carefully after the procedure.
Based on ESC 2024 Guidelines for the management of atrial fibrillation, NICE NG196 and Resuscitation Council UK tachycardia algorithm. Educational content: follow local protocols and prescriptions.