Critical and High-Risk Conditions in Atrial Fibrillation

Haemodynamic instability in atrial fibrillation (AF):

Most commonly occurs in tachy-AF with ventricular rate >170/min.
It is a condition in which cardiorespiratory failure and death may occur within 30 minutes.
Clinically, it most commonly presents as: tachypnoea, dyspnoea, exhaustion.
Recommended treatment is emergency electrical cardioversion (within minutes).

Relative haemodynamic instability in AF:

Most commonly occurs in tachy-AF with ventricular rate 120–170/min.
It is a condition in which cardiorespiratory failure may occur within 12–24 hours.
Clinically, it most commonly presents as: tachypnoea, dyspnoea, exhaustion.
Recommended treatment is urgent rate control (within hours) with an intravenous beta-blocker.
Pharmacological or electrical cardioversion may be considered if all criteria are met in 3 clinical situations:

Effective anticoagulation therapy for > 4 weeks.
CHA₂DS₂-VA score 0 or 1.
AF duration according to symptoms < 24 hours,

which, however, can never be known with 100% certainty, because the patient may have longer asymptomatic AF episodes.

Haemodynamic instability often occurs with tachy-AF with ventricular rate >150/min. Such a patient is tachypnoeic, dyspnoeic, and exhausted. Tachy-AF is most commonly triggered by:

An acute critical condition
An acute high-risk condition

Acute critical condition

This is an acute, life-threatening condition that usually develops within < 24 hours.
Patients require hospitalization in an intensive care unit; examples include:

sepsis, polytrauma, major surgery, major bleeding, myocardial infarction, pulmonary embolism.

Infographic illustrating a critical condition in a patient with atrial fibrillation, including severe thromboembolic complications with hemodynamic impact.

Acute critical condition and incidence of atrial fibrillation (AF)
Acute critical condition	Incidence of AF (%)
Cardiac surgery	30 – 60 %
Acute heart failure	25 – 50 %
Sepsis	20 – 46 %
Acute respiratory distress syndrome (ARDS)	20 – 40 %
Stroke	10 – 30 %
Myocardial infarction (STEMI / NSTEMI)	10 – 22 %
ICU patients	5 – 25 %
Pulmonary embolism	5 – 15 %
Major bleeding	3 – 5 %

Acute high-risk condition

This is a sudden, marked change in the patient’s condition that developed within < 24 hours.
Patients usually provoke a high-risk condition themselves; examples include:

extreme stress (hypertensive emergency), extreme physical exertion (sinus tachycardia, arterial hypertension), extreme sun exposure (dehydration, mineral imbalance), drug use, alcohol excess, discontinuation of chronic therapy.

Infographic illustrating high-risk atrial fibrillation associated with excessive intake of alcohol, caffeine, energy drinks, smoking, and drug use as triggers of arrhythmia.

Acute high-risk condition and incidence of atrial fibrillation (AF)
Acute high-risk condition	Incidence of AF (%)
Alcohol excess	20 – 30 %
Drug use (cocaine, methamphetamine, ecstasy)	5 – 15 %
Extreme physical exertion	2 – 4 %
Extreme stress	2 – 4 %
Extreme sun exposure	1 – 3 %
Coffee excess	1 – 2 %
Energy drink excess	1 – 2 %
Drug use (marijuana)	1 – 2 %

An acute critical or high-risk condition may trigger or worsen an AF episode. Based on history, 4 clinical situations are recognized:

Acute worsening of an AF episode

The patient already had an AF episode, and the acute condition worsened the course of the AF episode.

Acute episode in pre-existing AF

The patient has known AF. They were in sinus rhythm, but the acute condition triggered an AF episode.

Newly diagnosed AF

The patient has not had AF previously, and the acute condition triggered an AF episode that will persist as paroxysmal or persistent AF.

Triggered AF

The patient has not had AF previously, and the acute condition triggered an AF episode that terminated spontaneously and will not recur later (unless the patient experiences another acute condition).

Acute conditions and atrial fibrillation	Class
Electrical cardioversion is recommended in a haemodynamically unstable patient with atrial fibrillation (AF).	I
Intravenous landiolol is recommended for acute rate control in a relatively haemodynamically unstable patient with AF.	I
Intravenous beta-blocker (esmolol, atenolol, metoprolol) may be considered for acute rate control in a relatively haemodynamically unstable patient with AF.	IIa

After treatment and stabilization of the acute condition, AF spontaneously converts to sinus rhythm within 48 hours in up to 83 % of cases.

The following table summarizes key properties of beta-blockers,

most commonly used for acute AF treatment for rate control:

Beta-blockers (intravenous) – Acute treatment of atrial fibrillation (Rate control)
Beta-blocker (intravenous)	Dosing (intravenous)	Onset of effect	Duration of effect	β1/β2 selectivity	Effect on heart rate	Effect on blood pressure
Landiolol	Bolus 0.1 – 0.3 mg/kg, then infusion 1 – 40 µg/kg/min	1 min	15 min	255	↓↓	≈ 0
Esmolol	Bolus 0.5 mg/kg, then infusion 50 – 200 µg/kg/min	2 min	30 min	33	↓	↓
Atenolol	5 – 10 mg intravenous slowly (5 min), may be repeated after 10 min	5 min	12 hours	5	↓	↓
Metoprolol	2.5 – 5 mg intravenous every 2 – 5 min, max. 15 mg	20 min	5 – 8 hours	2	↓	↓

The following table shows (intravenous) beta-blocker dosing for tachy-AF according to body weight (50 kg, 70 kg, 100 kg):

Beta-blockers (intravenous) – Weight-based dosing
Beta-blocker (intravenous)	Patient (50 kg)	Patient (70 kg)	Patient (100 kg)
Landiolol	Bolus 5 – 15 mg Infusion 0.05 – 2 mg/min	Bolus 7 – 21 mg Infusion 0.07 – 2.8 mg/min	Bolus 10 – 30 mg Infusion 0.1 – 4 mg/min
Esmolol	Bolus 25 mg Infusion 2.5 – 10 mg/min	Bolus 35 mg Infusion 3.5 – 14 mg/min	Bolus 50 mg Infusion 5 – 20 mg/min
Atenolol	5 – 10 mg (over 5 min)	5 – 10 mg (over 5 min)	5 – 10 mg (over 5 min)
Metoprolol	2.5 – 5 mg (over 5 min)	2.5 – 5 mg (over 5 min)	2.5 – 5 mg (over 5 min)