Renewed impact of lidocaine on refractory ventricular arrhythmias in the amiodarone era

Background: Recent guidelines for treating ventricular fibrillation (VF) and ventricular tachycardia (VT) stress class III antiarrhythmic drugs, but some malignant arrhythmias refractory to these agents still occur in clinical practice. The possibility of a new treatment strategy involving lidocaine and amiodarone combination therapy was evaluated.

Methods: From September 2008 to September 2013, 62 patients were treated at our hospital with lidocaine. The medical records were retrospectively reviewed. Twenty inappropriate patients were excluded. The remaining 42 patients were analyzed. Patients were divided into two groups according to the effectiveness of lidocaine in terminating refractory ventricular arrhythmias: the effective group.

Results: LVEF was significantly higher in the lidocaine effective (E) group compared to the ineffective (I) group (44±16% vs. 32±10%, p=0.027). There were more patients already on amiodarone at the start of lidocaine therapy in the E group compared to the I group (11/26 vs. 1/16, p=0.012). Furthermore, patients receiving lidocaine without amiodarone were re-analyzed to estimate the actual effect of lidocaine. Of the 30 patients not receiving amiodarone, 15 were in the effective without amiodarone (E w/o A) group and 15 were in the ineffective without amiodarone (I w/o A) group. LVEF was significantly higher in the E w/o A group than in the I w/o A group (51±16% vs. 32±9%, p=0.001).

Conclusions: This retrospective study suggests that combination therapy with lidocaine and amiodarone can terminate most refractory ventricular arrhythmias. Even in patients with a sufficient LVEF not receiving amiodarone, it is possible that lidocaine can contribute to a favorable outcome.