Key Guidelines and Evidence

Atrial Fibrillation

• American College of Cardiology/American Heart Association/Heart Rhythm Society (ACC/AHA/HRS) Guidelines for the Management of Patients with Atrial Fibrillation:
  • Rate Control – In hemodynamically stable patients without an accessory pathway, an intravenous (IV) beta-blocker (e.g. metoprolol) or non-dihydropyridine calcium channel blocker (e.g. diltiazem) is recommended for acute rate control.
  • Rhythm Control – For pharmacologic cardioversion of acute AF, a class Ic antiarrhythmic like propafenone or flecainide is recommended, or dofetilide/ibutilide in patients without structural heart disease. Amiodarone can also be considered.
  • Anticoagulation – Anticoagulation with heparin or low molecular weight heparin is recommended as soon as possible for AF greater than 48 hours or of unknown duration before cardioversion.
  • Cardioversion – If rapid pharmacologic cardioversion is unsuccessful or not feasible, electrical cardioversion should be performed. This also allows cardioversion without prolonged anticoagulation.
  • Maintenance of Sinus Rhythm – After successful cardioversion, an oral antiarrhythmic like amiodarone, dofetilide, dronedarone, flecainide, propafenone, or sotalol can be considered for maintaining sinus rhythm depending on the presence of structural heart disease.

• Key Studies
  • RE-LY
    • In patients with atrial fibrillation, dabigatran given at a dose of 110 mg was associated with rates of stroke and systemic embolism that were similar to those associated with warfarin, as well as lower rates of major hemorrhage. Dabigatran administered at a dose of 150 mg, as compared with warfarin, was associated with lower rates of stroke and systemic embolism but similar rates of major hemorrhage.
  • ROCKET AF
    • In patients with atrial fibrillation, rivaroxaban was noninferior to warfarin for the prevention of stroke or systemic embolism. There was no significant between-group difference in the risk of major bleeding, although intracranial and fatal bleeding occurred less frequently in the rivaroxaban group.
  • Hasbrouck M, Nguyen TT. Acute management of atrial fibrillation in congestive heart failure with reduced ejection fraction in the emergency department. Am J Emerg Med. 2022 Apr 6;58:39-42.
    • In HFrEF patients with AF, there was no difference in total adverse events in patients treated with IV diltiazem compared to metoprolol. However, the diltiazem group had a higher incidence of worsening CHF symptoms defined as increased oxygen requirement within four hours or initiation of inotropic support within 48 h.

Supraventricular Tachycardia

• 2015 ACC/AHA/HRS Guidelines for the Management of Adult Patients With Supraventricular Tachycardia recommend:

• Vagal maneuvers and/or IV adenosine for initial management of stable AVNRT
  • Synchronized cardioversion if unstable
  • EPS for diagnosis if noninvasive monitoring unclear
  • Catheter ablation of slow pathway as preferred long-term therapy
  • Antiarrhythmic medications reasonable for certain patients

• Part 3: adult Advanced Cardiac Life Support: 2020 American Heart Association Guidelines Update for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care.
  • 2. Adenosine is recommended for acute treatment in patients with SVT at a regular rate.
    • COR 1, LOE B-R
  • 3. IV diltiazem or verapamil can be effective for acute treatment in patients with hemodynamically stable SVT at a regular rate.
    • COR 2a, LOE B-R
  • 4. IV β-adrenergic blockers are reasonable for acute treatment in patients with hemodynamically stable SVT at a regular rate.
    • COR 2a, LOE LD

Key Stuides

• Alabed S, Sabouni A, Providencia R, Atallah E, Qintar M, Chico TJ. Adenosine versus intravenous calcium channel antagonists for supraventricular tachycardia. Cochrane Database Syst Rev. 2017;10:CD005154.
  • Viewed randomised controlled trials (RCTs) that compare effects of adenosine versus CCAs in terminating SVT.
  • Moderate-quality evidence shows no differences in the number of people reverting to sinus rhythm who were treated with adenosine or CCA (89.7% vs 92.9%; OR 1.51, 95% confidence interval (CI) 0.85 to 2.68; participants = 622; studies = 7; I2 = 36%).

Ventricular Tachycardia

Monomorphic VT

Guideline Recommendations for Medications in Monomorphic VT

Summary of Key Evidence

• PROCAMIO Trial (2017): Procainamide superior to amiodarone for conversion of stable MVT (67% vs 38%, p<0.05) with fewer adverse events
• Marill et al (2010): Retrospective analysis found amiodarone and procainamide had similar efficacy for stable MVT (59% vs 43%, p=0.08)
• AHA/ACC/HRS guideline update (2017) changed recommendation to procainamide preferred over amiodarone based on efficacy and safety data

Polymorphic VT

AHA/ACC/HRS (2017)

• Intravenous magnesium can suppress episodes of torsades de pointes without necessarily shortening QT, even when serum magnesium is normal. Repeated doses may be needed, titrated to suppress ectopy and nonsustained VT episodes while precipitating factors are corrected.
• In patient with recurrent torases de pointes associated with acquired QT proklongation and bradycardia that cannot be suppressed with intravenous magnesium administration, increasing the heart rate with atrial or ventricular pacing or isoproterenol are recommended to suppress the arrhythmia
• Maintaining serum potassium between 4.5 mEq/L and 5 mEq/L shortens QT and may reduce the chance of recurrent torsades de pointes

Key Study

• Tzivoni D, Banai S, Schuger C, Benhorin J, Keren A, Gottlieb S, Stern S. Treatment of torsade de pointes with magnesium sulfate. Circulation. 1988 Feb;77(2):392-7.
  • Twelve consecutive patients who developed torsade de pointes (polymorphous ventricular tachycardia with marked QT prolongation, TdP) over a 4 year period were treated with intravenous injections of magnesium sulfate.
  • In nine of the patients a single bolus of 2 g completely abolished the TdP within 1 to 5 min, and in three others complete abolition of the TdP was achieved after a second bolus was given 5 to 15 min later.