Initial assessment (ECG)
Patient with tachycardia and suspected atrial fibrillation. The first step is to confirm the diagnosis with a 12-lead ECG. Once AF is confirmed, define the treatment strategy, starting with the identification of reversible secondary causes.
Reversible secondary causes
Screen for electrolyte or acid–base disturbances, pericarditis, myocarditis, hyperthyroidism, sepsis, anaemia, gastrointestinal bleeding, hypothermia, or drug toxicity. Also consider decompensated heart failure, acute coronary syndrome, and hypovolaemia. If any cause is identified, treat the underlying condition.
Hemodynamic stability and red flags
If no reversible cause is found, the therapeutic decision centres on rhythm vs rate control. First, assess hemodynamic stability. Instability presents with systolic BP < 90 mmHg associated with altered mental status, chest pain, dyspnoea, or presyncope/syncope. Other red flags include acute ischaemia with ST-segment changes, elevated cardiac biomarkers, or decompensated heart failure.
Accessory pathway and specialist support
If the patient is hemodynamically unstable, request specialist support. Do the same when an accessory pathway is suspected—e.g., wide, bizarre, or polymorphic QRS complexes; history of Wolff–Parkinson–White; or a delta wave on prior ECGs.
Treatment strategy: rhythm vs rate
In stable patients, choose between rhythm and rate control. Rate control is generally favoured in patients >65 years, with hypertension, without heart failure, those preferring this approach, refractory to prior antiarrhythmics, or minimally symptomatic. Rhythm control can be considered when significant symptoms persist despite adequate rate control.
Cardioversion and episode duration
The decision to perform pharmacological or electrical cardioversion depends on AF duration. If <48 hours, cardioversion can be considered directly. If >48 hours or unknown, a minimum of 3 weeks of effective anticoagulation is required, or alternatively, a transoesophageal echocardiogram to exclude intracardiac thrombus. Recent stroke/TIA, peripheral thromboembolism, mechanical valve, or rheumatic heart disease contraindicate immediate cardioversion without prior anticoagulation.
Rhythm control: drugs and exclusions
If rhythm control is chosen and no exclusion criteria are present (second/third-degree AV block, prolonged QT, hypokalaemia, pregnancy, or severe renal/hepatic impairment), antiarrhythmics such as amiodarone, flecainide, propafenone, or sotalol may be used. In structural, ischaemic, or valvular heart disease, or with LV hypertrophy, avoid flecainide and propafenone; prefer amiodarone or sotalol. In heart failure, amiodarone is usually the drug of choice.
Rate control: LVEF-dependent
When opting for rate control, selection depends on left-ventricular ejection fraction. If LVEF <40%, use low-dose beta-blockers (e.g., metoprolol) and consider adding digoxin. With preserved LVEF, beta-blockers, non-dihydropyridine calcium-channel blockers (diltiazem or verapamil), or digoxin can be used alone or in combination.
Chronic anticoagulation
After initial control, start maintenance therapy (rhythm or rate) according to the chosen strategy. In all cases, assess thromboembolic risk and the need for long-term anticoagulation based on the CHA₂DS₂-VASc score.
Shared decision-making and follow-up
Therapy should be individualised, considering symptoms, comorbidities, contraindications, and the patient’s informed preference. Ensure an appropriate follow-up plan after discharge.
