Arrhythmias are disturbances in cardiac rhythm that can range from benign to life-threatening. This article provides a comprehensive comparison of Atrial Fibrillation (AF), Atrial Flutter, Supraventricular Tachycardia (SVT), Ventricular Tachycardia (VT), Ventricular Fibrillation (VF), and Torsades de Pointes (TdP), including their ECG findings, causes, symptoms, and management.
2. Overview of Arrhythmias
| Arrhythmia | ECG Characteristics | Origin | Heart Rate | Clinical Features |
|---|---|---|---|---|
| Atrial Fibrillation (AF) | Irregularly irregular rhythm, no P waves, fibrillatory waves | Atria | 100-175 bpm | Palpitations, stroke risk, dyspnea, fatigue |
| Atrial Flutter | Sawtooth flutter waves, regular rhythm | Atria | ~150 bpm | Palpitations, dizziness, heart failure symptoms |
| Supraventricular Tachycardia (SVT) | Narrow QRS, P waves buried in QRS | AV node, atria | 150-250 bpm | Sudden onset palpitations, syncope, dizziness |
| Ventricular Tachycardia (VT) | Wide QRS, monomorphic or polymorphic | Ventricles | 100-250 bpm | Dizziness, syncope, may lead to cardiac arrest |
| Ventricular Fibrillation (VF) | Chaotic, disorganized waves, no QRS | Ventricles | >300 bpm | Cardiac arrest, pulseless patient |
| Torsades de Pointes (TdP) | Polymorphic VT with twisting QRS, prolonged QT | Ventricles | 150-300 bpm | Syncope, sudden cardiac death |
3. Atrial Arrhythmias
(A) Atrial Fibrillation (AF)
- Pathophysiology: Multiple chaotic reentrant circuits in the atria.
- Common Causes: Hypertension, ischemic heart disease, heart failure, hyperthyroidism, alcohol use.
- ECG Features:
- Irregularly irregular rhythm
- No P waves, fibrillatory waves
- Management:
- Rate Control: Beta-blockers, calcium channel blockers (Diltiazem, Verapamil), Digoxin.
- Rhythm Control: Amiodarone, Flecainide, Cardioversion (if <48h or anticoagulated).
- Stroke Prevention: CHA₂DS₂-VASc score for anticoagulation.
(B) Atrial Flutter
- Pathophysiology: Single reentrant circuit around the tricuspid valve.
- Common Causes: Similar to AF, post-cardiac surgery.
- ECG Features:
- Sawtooth flutter waves (~300 bpm atrial rate)
- Ventricular rate ~150 bpm (2:1 conduction)
- Management:
- Rate Control: Beta-blockers, calcium channel blockers.
- Rhythm Control: Cardioversion, Amiodarone, Ablation of flutter circuit.
(C) Supraventricular Tachycardia (SVT)
- Pathophysiology: AV nodal reentrant tachycardia (AVNRT) or AV reentrant tachycardia (AVRT in WPW).
- ECG Features:
- Narrow QRS tachycardia
- P waves buried in QRS or retrograde P waves
- Management:
- Acute: Vagal maneuvers → Adenosine 6mg IV → Beta-blockers, Verapamil if resistant.
- Chronic: Beta-blockers, CCBs, Catheter ablation for recurrent cases.
4. Ventricular Arrhythmias
(A) Ventricular Tachycardia (VT)
- Pathophysiology: Reentrant circuits in the ventricles.
- Common Causes: Ischemic heart disease, electrolyte imbalances, cardiomyopathy.
- ECG Features:
- Wide QRS (>120 ms)
- Monomorphic (same QRS shape) or Polymorphic (variable QRS)
- Management:
- Stable VT: Amiodarone 150mg IV, Lidocaine, Beta-blockers.
- Unstable VT: Immediate synchronized cardioversion.
- Recurrent VT: ICD (Implantable Cardioverter-Defibrillator).
(B) Ventricular Fibrillation (VF)
- Pathophysiology: Chaotic ventricular activity leading to cardiac arrest.
- Common Causes: Myocardial infarction, electrolyte disturbances, drug toxicity.
- ECG Features:
- Completely chaotic, no organized QRS complexes
- Management:
- CPR + Defibrillation (Shockable Rhythm)
- Epinephrine 1mg IV every 3-5 min
- Amiodarone 300mg IV after 3rd shock
(C) Torsades de Pointes (TdP)
- Pathophysiology: Polymorphic VT due to prolonged QT interval.
- Common Causes: Hypokalemia, Hypomagnesemia, QT-prolonging drugs (e.g., Haloperidol, Azithromycin).
- ECG Features:
- Polymorphic QRS that twists around baseline
- Prolonged QT interval
- Management:
- IV Magnesium Sulfate (1-2g over 10 min)
- Correct electrolyte imbalances
- Avoid QT-prolonging drugs
- Overdrive pacing if refractory
5. Summary Table: Management of Arrhythmias
| Arrhythmia | Acute Management | Chronic Management |
|---|---|---|
| Atrial Fibrillation | Rate control (Beta-blockers, CCBs), Cardioversion if unstable | Anticoagulation, Rhythm control for selected cases |
| Atrial Flutter | Rate control, Cardioversion | Catheter ablation is often curative |
| Supraventricular Tachycardia | Vagal maneuvers → Adenosine 6mg IV | Beta-blockers, CCBs, Ablation if recurrent |
| Ventricular Tachycardia | Amiodarone 150mg IV, Cardioversion if unstable | ICD for recurrent VT |
| Ventricular Fibrillation | Immediate Defibrillation, CPR, Epinephrine | ICD placement in survivors |
| Torsades de Pointes | IV Magnesium, Correct electrolytes | Avoid QT-prolonging drugs |
6. Key Takeaways
✅ AF is irregularly irregular, requires stroke prevention (CHA₂DS₂-VASc scoring).
✅ Atrial Flutter has sawtooth waves and responds well to ablation.
✅ SVT is a rapid narrow-complex tachycardia that can be terminated with vagal maneuvers or adenosine.
✅ VT is a wide-complex tachycardia, requiring amiodarone or cardioversion depending on stability.
✅ VF is a cardiac arrest rhythm requiring immediate defibrillation.
✅ Torsades de Pointes is polymorphic VT due to prolonged QT and treated with magnesium sulfate.
