A-Fib Introduction

1. Background/Introduction � • Introduction: o Atrial fibrillation (AF) is a type of fast, irregular heartbeat that happens when the top chambers of the heart (atria) are not working together o It’s the most common type of irregular heart rhythm, seen in about 2% of people. • Epidemiology: o More prevalent in men, Caucasians, and the elderly population. • Types/Classifications: • • • • • Paroxysmal AF o AF that comes and goes Persistent AF o AF lasts more than 7 days Long-standing Persistent AF o AF that continues for more than 12 months Permanent AF o When doctor and patient decide not to try to restore normal rhythm anymore o Focus is on rate control and stroke prevention Risk Factors: o Increasing age o Hypertension o Diabetes mellitus o Myocardial infarction (MI) o Heart failure o Obesity o Obstructive sleep apnea o Cardiothoracic surgery o Smoking and alcohol use 2. Pathophysiology/Etiology Atrial fibrillation happens when electrical signals in the upper part of the heart (atria) don’t follow the normal path. These signals can be extra, fast, or go in loops, causing the atria to beat irregularly. What can cause this? • • • Heart problems like: o Heart attacks (ischemic heart disease) o Heart failure o Heart inflammation (pericarditis) o Heart surgery Other medical issues like: o Overactive thyroid (hyperthyroidism) o Low oxygen (hypoxia) o Imbalances in minerals like potassium, magnesium, or calcium Medications or drugs like: o Some heart meds (antiarrhythmics, digoxin) o Antidepressants (TCAs) o Antipsychotics (like haloperidol) o Stimulants (like decongestants, caffeine) o Certain antibiotics (erythromycin) o Older drugs like terfenadine or cisapride 3. Signs and Symptoms • • • Pertinent Labs: o Thyroid function tests o Renal and hepatic function tests o Electrolyte levels (potassium, magnesium, calcium) Presenting Symptoms: o Asymptomatic or symptomatic:  Palpitations  Tachycardia  Dizziness or lightheadedness  Tachypnea and shortness of breath  Syncope  Shock in severe cases  Decline in functional status Assessment/Diagnostic Criteria/Tools: o History and physical examination o Electrocardiogram (ECG) o Exercise testing or 6-minute walk test o Chest radiography 4. Treatment • Approach to Therapy: Goals include: 1. Preventing thromboembolism/stroke. 2. Controlling ventricular rate (rate control). 3. Converting and maintaining normal sinus rhythm (rhythm control). o Pharmacological Therapy: 1. 1st Line/2nd Line Agents/Medication Classes:  Anticoagulation:  Oral anticoagulants recommended based on CHA₂DS₂VASc score:  DOACs (dabigatran, rivaroxaban, apixaban, edoxaban) preferred over warfarin unless severe mitral stenosis or mechanical heart valves present.  Warfarin (INR target: 2-3) used when DOAC contraindicated.  Rate Control (AV nodal blockers):  Beta-blockers (metoprolol, atenolol, esmolol, propranolol, carvedilol)  Non-dihydropyridine calcium channel blockers (verapamil, diltiazem)  Digoxin (useful in sedentary patients or HF)  Amiodarone (occasionally used for rate control) Goal: Resting heart rate <80 bpm; a more lenient goal (<110 bpm) acceptable if asymptomatic and preserved LVEF. Rhythm Control (pharmacologic cardioversion):  Class Ic agents (flecainide, propafenone)  Class III agents (dofetilide, ibutilide, amiodarone)  "Pill-in-the-pocket" method (flecainide or propafenone with BB/non-DHP CCB; after observed safety in controlled setting)   Long-term rhythm maintenance agents:     Amiodarone (effective but significant toxicity risks) Dofetilide, dronedarone, flecainide, propafenone, sotalol (consider risks/benefits) Rationale:  Anticoagulation prevents stroke/thromboembolism.  Rate control stabilizes hemodynamics and protects ventricles.  Rhythm control can improve symptoms, hemodynamics, and quality of life. Drug-specific unique aspects:  DOACs: renal adjustments needed, less monitoring compared to warfarin.  Amiodarone: risk for pulmonary fibrosis, thyroid dysfunction, hepatotoxicity; requires regular monitoring (thyroid, liver function, pulmonary).  Class III agents (dofetilide, ibutilide): Risk for QT prolongation and torsades de pointes; hospitalization needed when initiating dofetilide. Duration of Therapy:  Anticoagulation usually lifelong based on stroke risk.  Rate control generally lifelong.  Rhythm control duration individualized based on patient response, tolerability, and recurrence. o Non-pharmacological Therapy:  Electrical Cardioversion (DCC):  Immediate cardioversion recommended for unstable hemodynamics or failure of drug therapy.  Catheter Ablation: minimally invasive procedure creating scar tissue via heat/cold/radiofrequency energy.  Maze Procedure: surgical procedure creating scar tissue to interrupt abnormal electrical signals, often done alongside other cardiac surgery.  Lifestyle Modifications: Smoking cessation, weight management, alcohol moderation, and management of coexisting conditions (e.g., sleep apnea, hypertension).