Nifekalant-Magnesium Cocktail for Chemical Cardioversion of Atrial Flutter: A Multicenter Pilot Study

Area of Science:

• Cardiology
• Electrophysiology
• Pharmacology

Background:

• Pharmacologic cardioversion for atrial flutter (AFL) is challenging, especially for elderly or frail patients unsuitable for ablation.
• Nifekalant is effective for AFL but carries risks of QT prolongation and torsades de pointes (TdP).
• Magnesium sulfate may reduce the risk of TdP associated with nifekalant.

Purpose of the Study:

• To evaluate the feasibility and safety of using intravenous magnesium sulfate followed by nifekalant for chemical cardioversion of symptomatic persistent AFL.
• To assess the efficacy of this combination therapy in terminating AFL within 60 minutes.
• To identify factors associated with successful AFL termination.

Main Methods:

• A multicenter, investigator-initiated pilot study involving 86 patients with symptomatic persistent AFL.
• Patients received intravenous magnesium sulfate followed by nifekalant.
• Primary outcome was AFL termination within 60 minutes; safety outcomes, including TdP, were monitored. Multivariable logistic regression was used to identify predictive factors.

Main Results:

• Atrial flutter terminated in 42 patients (48.8%).
• Successful cardioversion was achieved within 20 minutes in 80% of responders.
• Larger left atrial diameter was linked to a lower chance of termination. Adverse events were rare (2.3%) and included sinus pauses and transient hypotension; no TdP occurred.

Conclusions:

• The combination of nifekalant and magnesium sulfate shows potential as a feasible and safe option for chemical cardioversion of AFL.
• Further investigation in larger clinical trials is warranted to confirm these findings.
• This approach may offer an alternative for patients who are not candidates for catheter ablation.