Study objectives: To evaluate prospectively, the tolerability and safety of intravenous cibenzoline therapy, for the cardioversion of spontaneous monomorphic ventricular tachycardia (VT).
Setting and patients: Between February 1990 and December 1996, fifty-eight patients aged 59+/-10 years old (fifty-three males, five females), with spontaneous VT not causing cardiac arrest, received intravenous cibenzoline. Their underlying heart conditions were: ischemic heart disease , dilated cardiomyopathy , right ventricular dysplasia , hypertrophic cardiomyopathy , valvulopathy , Fallot's Tetralogy  and primary arrhythmogenic disease . The left ventricular ejection fraction was 42+/-13% (range 20%-76%).
Results: The mean dose of cibenzoline was 70+/-12 mg. The tachycardia stopped within 6+/-3 min in 47 (81%) patients. Side effects from cibenzoline occurred in two patients. The hemodynamic complications were limited to hypotension, that required vasopressor therapy in one patient. The only apparent proarrhythmic effect consisted of an isolated change in the morphology of the VT, that resolved spontaneously on withdrawal of the drug. No mortality occurred at the hospital.
Conclusion: With appropriate rules for its administration, intravenous cibenzoline has the potential to become one of the first-line antiarrhythmic drugs, to be used for cardioversion of patients with spontaneous VT.