Heart Rhythm Disorders: Types, Diagnosis, and Treatments
Heart Rhythm Disorders (Arrhythmias)
Types of Arrhythmias
Hyperactive Arrhythmias
Supraventricular Origin
- Extrasystole (headset)
- Atrial tachycardia
- Atrial flutter
- Atrial fibrillation
- Nodal extrasystole
- AV junctional tachycardia
Ventricular Origin
- Ventricular extrasystole
- Ventricular tachycardia
- Ventricular flutter
- Ventricular fibrillation
Pre-Excitation Syndromes
Underactive or Slow Arrhythmias
Altered Automaticity
Supraventricular Origin
- Sinus bradycardia
- Sinus arrest
- Atrial escape beat
- Atrial pacemaker migration
- Nodal escape beat
- Nodal escape rhythm
Ventricular Origin
- Ventricular escape beat
- Ventricular escape rhythm
Impaired Conduction
- Sinoatrial block
- Atrioventricular block
Atrial Fibrillation (AF) Treatment
Ventricular Response Control
Essential for almost all patients due to their tendency for a high ventricular response. Sometimes, symptom control may be the only applicable option. Acute and chronic drug administration (IV with VO). Beta-blockers, calcium channel blockers (verapamil, diltiazem), digoxin.
Restoring Sinus Rhythm
Depends on heart disease, atrial size (> 45 mm), symptoms, and arrhythmia duration. 60% of AF reverses within 24 hours. Anticoagulation is necessary before cardioversion if the duration exceeds 48 hours. Urgent electrical cardioversion is required for hemodynamic compromise.
Pharmacological Cardioversion
- Flecainide or propafenone (without ventricular dysfunction)
- Amiodarone (with ventricular dysfunction)
Electrical Cardioversion
Synchronized, with patient sedation, at 200-360 joules. Anticoagulation for 3-4 weeks before and after cardioversion with Sintrom, maintaining an INR of 2-3, is necessary if AF persists for over 48 hours.
Preventing Recurrences
High likelihood of recurrence without preventive antiarrhythmic therapy. Avoid triggers (alcohol, tobacco).
Patients Without Heart Disease
Class IC drugs (flecainide, propafenone) combined with an AV nodal blocker.
Patients With Heart Disease
- Sotalol
- Amiodarone (Class III)
- Dronedarone
- Atrial partitioning surgery
- Radiofrequency catheter ablation
- Implantable cardioverter-defibrillators (ICDs)
- Implantable pacemakers
Preventing Embolic Complications
Chronic anticoagulation for high-risk patients (heart failure, mitral valve disease, history of embolism, hypertension, advanced age, diabetes). Stroke risk in paroxysmal and chronic AF. Sintrom to maintain an INR of 2-3. Aspirin (300 mg/day) may be considered for patients under 60 without embolism risk factors. Aspirin plus clopidogrel.
Atrial Flutter
Abnormal sawtooth-shaped P waves (F waves) at approximately 300 bpm, with consistent morphology. Often presents with AV block (usually 2:1). Ventricular rate around 150 bpm. Symptoms vary with ventricular response and presence/absence of associated heart disease. Palpitations, dizziness, dyspnea, syncope, angina, heart failure.
Atrial Flutter Treatment
Acute Episode
Similar to atrial fibrillation, but with poorer response to drug treatment or cardioversion for ventricular rate control. Cardioversion with low energy (50 joules) or headset pacing.
Ventricular Response Control
AV node blockers (beta-blockers, calcium channel blockers, digoxin).
Anticoagulation
Similar to atrial fibrillation, but flutter carries a lower embolism risk.
Radiofrequency Ablation
Ablation of the cavotricuspid isthmus (common flutter) is effective.
Recurrence Prevention
Antiarrhythmics (propafenone, flecainide, amiodarone) have limited effectiveness.