What is the recommended treatment for ventricular tachycardia, ventricular fibrillation, paroxysmal supraventricular tachycardia, and atrial fibrillation?

Treatment of Ventricular Tachycardia, Ventricular Fibrillation, Paroxysmal Supraventricular Tachycardia, and Atrial Fibrillation

Ventricular Fibrillation (VF)

Immediate unsynchronized defibrillation is the only effective treatment for ventricular fibrillation, with no role for pharmacologic therapy before shock delivery. 1

• Deliver high-energy unsynchronized shocks (defibrillation doses) immediately upon rhythm recognition 1
• Do not attempt synchronized cardioversion for VF, as the device may fail to sense a QRS wave and withhold the shock 1
• Self-adhesive defibrillation pads minimize sparking risk and are preferred over manual paddles 1
• If using manual paddles, use gel pads rather than pastes to prevent spark formation between paddles 1
• Minimize oxygen flow across the chest during defibrillation attempts to reduce fire hazard 1

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Ventricular Tachycardia (VT)

Pulseless VT

Pulseless ventricular tachycardia is treated identically to ventricular fibrillation with immediate high-energy unsynchronized defibrillation. 1

• Deliver unsynchronized shocks at defibrillation doses without delay 1
• Do not use synchronized cardioversion for pulseless VT 1

Polymorphic VT with Pulse

Polymorphic (irregular) ventricular tachycardia with pulses requires high-energy unsynchronized shocks, not synchronized cardioversion. 1

• Treat with defibrillation doses (unsynchronized shocks) 1
• Synchronized cardioversion is inappropriate because the irregular morphology prevents reliable QRS sensing 1

Monomorphic VT with Pulse (Hemodynamically Unstable)

Synchronized cardioversion is the treatment of choice for unstable monomorphic VT with pulses. 1

• Perform synchronized cardioversion immediately when hypotension, altered mental status, shock, chest pain, or acute heart failure is present 1
• Synchronization avoids shock delivery during the vulnerable period of the cardiac cycle, preventing degeneration to VF 1

Monomorphic VT with Pulse (Hemodynamically Stable)

For stable monomorphic VT, direct current cardioversion remains most efficacious, but procainamide is the preferred antiarrhythmic if medical management is chosen. 2

• Procainamide demonstrates the greatest efficacy among antiarrhythmic agents: administer 10 mg/kg IV at 50–100 mg/min over 10–20 minutes with continuous blood pressure and ECG monitoring 2
• Amiodarone receives only a IIb recommendation (compared to procainamide's IIa) from the American Heart Association 2
• Sotalol also receives a IIb recommendation 2
• Lidocaine has lower efficacy than procainamide 2
• Direct current cardioversion should be strongly considered even in stable patients, as it is more effective than any pharmacologic option 2

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Paroxysmal Supraventricular Tachycardia (PSVT)

Hemodynamically Unstable PSVT

Immediate synchronized cardioversion after sedation is mandatory for unstable PSVT and achieves near-100% termination. 1, 3

• Proceed directly to synchronized cardioversion (50–100 J) without attempting vagal maneuvers or drug therapy when hypotension, altered mental status, shock, chest pain, or acute heart failure is present 1, 3
• Do not delay definitive treatment with pharmacologic trials in unstable patients 3

Hemodynamically Stable PSVT

Vagal maneuvers are the mandatory first-line intervention, followed by adenosine if unsuccessful. 1, 3

Vagal Maneuvers (First-Line)

• Modified Valsalva maneuver (patient supine, bearing down 10–30 seconds to generate 30–40 mmHg intrathoracic pressure) terminates 43% of PSVT episodes 1, 3
• Carotid sinus massage (5–10 seconds steady pressure after confirming absence of carotid bruit) is an alternative technique 1, 3
• Ice-water facial immersion (cold wet towel on face) activates the diving reflex 1
• Overall vagal maneuver success rate is approximately 27–28% 1, 3
• Never apply pressure to the eyeball—this technique is dangerous and abandoned 1, 3

Adenosine (First-Line Pharmacologic Agent)

Adenosine is the drug of choice for acute PSVT termination, achieving 90–95% conversion for AVNRT and 78–96% for AVRT. 1, 3, 4

• Dosing protocol: 6 mg rapid IV push (over 1–2 seconds) through a proximal vein, followed immediately by 20 mL saline flush 1, 3
• If no conversion within 1–2 minutes, administer 12 mg rapid IV push with flush 1, 3
• A third 12 mg dose may be given if needed (maximum cumulative dose 30 mg) 3
• Reduce initial dose to 3 mg in patients taking dipyridamole or carbamazepine, cardiac transplant recipients, or when administering via central venous access 1, 3
• Increase dose in patients with high caffeine, theophylline, or theobromine levels 1, 3
• Absolute contraindications: active asthma/bronchospasm (risk of severe bronchospasm), second- or third-degree AV block, sick sinus syndrome without pacemaker 1, 3
• A defibrillator must be immediately available when administering adenosine to patients in whom Wolff-Parkinson-White syndrome is possible, as adenosine may precipitate atrial fibrillation with rapid ventricular rates 1, 3
• Common transient side effects (<60 seconds): flushing, dyspnea, chest discomfort 1, 3

Alternative Pharmacologic Options (When Adenosine Fails or Is Contraindicated)

Intravenous diltiazem is the preferred alternative, achieving 64–98% conversion. 1, 3

• Diltiazem: 15–20 mg (≈0.25 mg/kg) IV over 2 minutes; slower infusion over 20 minutes reduces hypotension risk 3
• Verapamil: 2.5–5 mg IV over 2 minutes is an acceptable alternative calcium-channel blocker 1, 3
• Beta-blockers: IV metoprolol 2.5–5 mg every 2–5 minutes (maximum 15 mg over 10–15 minutes) or esmolol for short-term control 1, 3
• Absolute contraindications for calcium-channel blockers: inability to exclude ventricular tachycardia, pre-excited atrial fibrillation (WPW), suspected systolic heart failure, or any hemodynamic instability 1, 3
• Never combine IV calcium-channel blockers with IV beta-blockers due to synergistic hypotension and bradycardia 3

Synchronized Cardioversion (Rescue for Stable Patients)

• When all pharmacologic options fail or are contraindicated, elective synchronized cardioversion with sedation yields 80–98% success 3

Post-Conversion Management

• Continuous cardiac monitoring is essential immediately after conversion, as premature complexes frequently trigger recurrent PSVT within seconds to minutes 1, 3
• If immediate recurrence occurs, administer a longer-acting AV-nodal blocker (oral diltiazem or beta-blocker) 1, 3
• When adenosine unmasks atrial flutter or atrial tachycardia, manage with a longer-acting AV-nodal blocker for rate control 3

Long-Term Management

Catheter ablation is first-line definitive therapy for recurrent symptomatic PSVT, with single-procedure success rates of 94.3–98.5%. 3, 4

• Catheter ablation is the most effective, safe, and cost-effective approach for preventing recurrent PSVT 3, 4
• If ablation is declined, oral beta-blockers, diltiazem, or verapamil are first-line for prevention of recurrent AVNRT 3

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Atrial Fibrillation (AF)

Hemodynamically Unstable AF

Immediate synchronized cardioversion is mandatory for unstable atrial fibrillation. 1, 5

• Perform synchronized cardioversion with an initial monophasic shock of 200 J for atrial fibrillation, preceded by brief general anesthesia or conscious sedation whenever possible 1, 5
• Do not delay cardioversion to attempt rate control in unstable patients 5

Hemodynamically Stable AF – Rate Control Strategy

Beta-blockers are the preferred first-line agent for rate control in hemodynamically stable AF, particularly when ongoing ischemia is present. 5

• Intravenous metoprolol: 2.5–5.0 mg every 2–5 minutes to a total of 15 mg over 10–15 minutes 5
• Intravenous atenolol: 2.5–5.0 mg over 2 minutes to a total of 10 mg in 10–15 minutes 5
• Beta-blockers simultaneously address rapid ventricular response and reduce myocardial oxygen demand 5
• Do not use digoxin as monotherapy in active patients, as it only controls rate at rest and is ineffective during exercise 5
• Do not use diltiazem or verapamil in patients with reduced ejection fraction (LVEF ≤40%) or heart failure, as they worsen hemodynamic compromise 5

AF with Pre-Excitation (Wolff-Parkinson-White)

In pre-excited atrial fibrillation, avoid all AV-nodal blocking agents and proceed to cardioversion or use procainamide. 1, 3

• Never administer digoxin, beta-blockers, diltiazem, verapamil, or amiodarone in patients with pre-excited AF, as they may increase the risk of ventricular fibrillation 1
• If hemodynamically unstable, proceed immediately to synchronized cardioversion 3
• If stable, administer IV procainamide or ibutilide to slow accessory-pathway conduction 3

Anticoagulation Strategy

Assess stroke risk using CHA₂DS₂-VASc score immediately to determine anticoagulation need. 5

• For CHA₂DS₂-VASc score ≥2, direct oral anticoagulants (DOACs) such as apixaban, rivaroxaban, or edoxaban are recommended over warfarin due to lower bleeding risk 5
• Continue aspirin (75–325 mg once daily) and clopidogrel for NSTEMI management if applicable 5
• Do not add antiplatelet treatment to anticoagulation for the goal of preventing ischemic stroke or thromboembolism in AF patients 5

Cardioversion Approach (Elective)

• Therapeutic oral anticoagulation for at least 3 weeks before scheduled cardioversion is required to prevent procedure-related thromboembolism 5
• Post-cardioversion, oral anticoagulation must continue for at least 4 weeks in all patients and long-term in patients with thromboembolic risk factors 5

Long-Term Management

For patients with no or minimal structural heart disease, flecainide, propafenone, and sotalol are first-line antiarrhythmic agents. 1

• Flecainide, propafenone, and sotalol are recommended as initial therapy because they are well tolerated and devoid of extracardiac organ toxicity 1
• Amiodarone, disopyramide, procainamide, and quinidine are second- or third-line choices with greater potential for adverse reactions 1
• For patients with heart failure, amiodarone or dofetilide are the safest options for maintaining sinus rhythm 1
• For patients with ischemic heart disease, sotalol is considered first unless heart failure is present; amiodarone and dofetilide are secondary agents 1
• For patients with hypertension without LVH, flecainide and propafenone are preferred; amiodarone, dofetilide, and sotalol are secondary choices 1

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Critical Safety Pitfalls Across All Arrhythmias

• Never delay cardioversion in hemodynamically unstable patients to attempt vagal maneuvers or drug therapy 1, 3
• Never administer calcium-channel blockers when ventricular tachycardia or pre-excited atrial fibrillation cannot be excluded, as this may precipitate ventricular fibrillation and death 1, 3
• Never use adenosine in patients with asthma due to the risk of severe bronchospasm 1, 3
• Never apply pressure to the eyeball as a vagal maneuver—this technique is dangerous and abandoned 1, 3
• Never use synchronized cardioversion for VF or pulseless VT, as the device may not deliver a shock 1
• Never administer verapamil for wide QRS-complex tachycardias of unknown etiology 1
• Always obtain a 12-lead ECG during tachycardia to differentiate mechanisms and identify pre-excitation 1, 3