The Efficacy of Ajmaline in Ventricular Arrhythmias after Failure of Lidocaine Therapy in the Acute Phase of Myocardial Infarction

Forty-three patients in the acute phase of myocardial infarction who were resistant to conventional doses of lidocaine received Ajmaline intravenously (50 mg bolus followed by constant infusion rate of 1-1.5 mg/min). Dangerous ventricular arrhythmias were abolished in 72% of this group of patients (group A). In the remaining patients (28%), Ajmaline was found to be ineffective (group B). There was no reduction of systolic or diastolic blood pressure and there was an insignificant increase in heart rate. Atrio-ventricular or intraventricular conduction defects appeared in 46% of the patients described. There was a statistically significant increase in occurrence of heart blocks in group B patients and among these complete left bundle branch block (CLBBB) was the most prevalent. Atrio-ventricular or intraventricular conduction defects were transient, appearing between 8-36 h (mean 23 h), and were not accompanied by reduction of ventricular rate. Conduction defects disappeared within several hours (up to 24 hours) after Ajmaline was discontinued. It is concluded that Ajmaline administered by this regimen is an effective alternative agent for patients with ventricular arrhythmia not controlled by lidocaine in the acute phase of myocardial infarction.