Atrial fibrillation (AF) and flutter Domina Petric, MD

Atrial fibrillation Chaotic, irregular atrial rhythm at 300-600 bpm. The AV node responds intermittently: irregular ventricular rate. Cardiac output drops by 10-20%. AF is common in the elderly. The main risk is embolic stroke.

AF causes heart failure heart ischaemia arterial hypertension myocardial infarction pulmonary embolism mitral valve disease pneumonia

AF causes hyperthyroidism caffeine alcohol post-operative AF hypokalemia hypomagnesemia

AF causes cardiomyopathy constrictive pericarditis sick sinus syndrome lung carcinoma atrial myxoma endocarditis haemochromatosis idiopatic

Symptoms asymptomatic chest pain palpitations dyspnoea faintness

Signs Irregularly irregular pulse! The apical pulse is greater than the radial rate. First heart sound is of variable intensity. There may be signs of left ventricular failure.

Image source: Lifeinthefastlane.com Absent P waves, irregular QRS complexes.

Blood tests Urea, electrolytes, kreatinine Cardiac enzymes Thyroid function tests

Other tests Echocardiography: left atrial enlargement, mitral valve disease, poor left ventricle function and other structural abnormalities.

Conversion of atrial fibrillation Within 48 hours from acute onset, propafenone 600 mg per os in patients without structural heart disease. Within 48 hours, amiodarone 300 mg per os in patients with structural heart disease. Electrocardioversion!

Conversion of atrial fibrillation >48 hours Immediate electrocardioversion: transesophageal echocardiography + 5000 IJ LMWH OR Electrocardioversion after 3 weeks of warfarin therapy.

Conversion of atrial fibrillation Immediate electrocardioversion after period of 48 hours can be done only if transoesophageal echocardiography shows that the heart is thrombus free.

Alternative drug cardioversion Amiodarone iv. 5 mg/kg over 1 h, then 900 mg over 24 hours via a central line. Amiodarone 200 mg every 8 hours for 1 week, 200 mg every 12 hours next week and 100-200 mg every 24 hours as a maintenance therapy. Flecainide 2 mg/kg iv. over 10-30 minutes, max. 150 mg OR 300 mg per os.

Flecainide It can be used only if the patient is stable and there is no known ischaemic heart disease or Wolff-Parkinson-White syndrome.

Chronic AF Main goals are: rate control anticoagulation

Rate control Beta blocker (BB) or rate-limiting Ca-blocker (CB). Alternatives are digoxin and amiodarone. BB should not be combined with diltiazem and verapamil!

Rhythm control Rhythm control is prefered in: symptomatic patients congestive cardiac failure younger patients patients presenting for the first time with lone AF AF from a corrected precipitant (electrolytes disbalance)

Rhythm control Electrocardioversion! Pharmacological cardioversion! AV node ablation! Maze procedure! Pacing! Pulmonary vein ablation!

Acute anticoagulation LMWH in preparation for electrocardioversion. Warfarin can also be used for elective electrocardioversion preparation.

Chronic anticoagulation Anticoagulation with warfarin to aim for an INR 2-3. Aspirin 300 mg per os can be used in patients with contraindications for warfarine use with very low risk of emboli. Very low risk include younger than 65 years, NO hypertension, diabetes, LV dysfunction, rheumatic valve disease. past MI or TIA.

Contraindications for warfarin bleeding diathesis platelets <50 x 109/L compliance issues frequent falls NSAID use past intracranial bleeds low haemoglobin

Chronic anticoagulation Dabigatran is a direct thrombin inhibitor. There is no need for regular laboratory INR monitoring and dose adjustment. Dose is 110 mg every 12 hours per os. Contraindications for dabigatran are severe renal and liver impairment, active bleeding, lesion at risk of bleeding, low level of clotting factors.

Interactions with dabigatran heparin clopidogrel NSAIDS GPIIb/IIIa antagonists p-glycoprotein inhibitors like verapamil, amiodarone, clarithromycin

Atrial flutter ECG: continous atrial depolarisation, heart rate usually 300 bpm, but very variable, sawtooth baseline and 2:1 AV block.

Lifeinthefastlane.com

Treatment Anticoagulation and electrocardioversion Amiodarone, sotalol or BB Cavotricuspid isthmus ablation

Literature Oxford Handbook of Clinical Medicine. Longmore M. Wilkinson I. B. Baldwin A. Elizabeth W. Ninth edition. Lifeinthefastlane.com