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The Role of Combination Therapy with Mexiletine and Procainamide in Patients with Inducible Sustained Ventricular Tachycardia Refractory to Intravenous Procainamide
Author(s) -
WIDERHORN JOSEF,
SAGER PHILIP T.,
RAHIMTOOLA SHAHBUDIN H.,
BHANDARI ANIL K.
Publication year - 1991
Publication title -
pacing and clinical electrophysiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.686
H-Index - 101
eISSN - 1540-8159
pISSN - 0147-8389
DOI - 10.1111/j.1540-8159.1991.tb04090.x
Subject(s) - procainamide , medicine , mexiletine , refractory (planetary science) , anesthesia , cardiology , ventricular tachycardia , physics , astrobiology
This study evaluated the role of serial electropharmacological testing on combination therapy with mexiletine and procainamide in 20 patients with inducible sustained ventricular tachycardia (VT) refractory to intravenous procainamide. The clinical arrhythmias were cardiac arrest in five patients, sustained VT in 11 patients, and recurrent syncope of presumably arrhythmic origin in four patients. The mean left ventricular election fraction (LVEF) was 0.40 ± 0.12 (mean ± SD). All patients had inducible sustained VT at baseline and after administration of intravenous procainamide. All 20 patients underwent elec‐tropharmacological testing on combination therapy with mexiletine and procainamide. The mean cycle length of inducible sustained VT was 251 ± 48 ms at baseline, 324 ± 81 ms on intravenous procainamide (P < 0.014 vs baseline), and 365 ± 82 ms on combination therapy (P < 0.0001 vs baseline, P = NS vs intravenous procainamide). Combination therapy did not suppress VT inducibility, nor did it make VT more difficult to induce in 19 of 20 patients. The remaining one patient had a partial response (runs of nonsustained VT, longest 10 seconds). Furthermore, combination therapy did not significantly prolong the VT cycle length over and above that observed during testing with intravenous procainamide. Therefore, in patients with inducible sustained VT refractory to procainamide during initial electropharma‐cological testing, mexiletine in combination with procainamide appears to be of little or no value and serial electropharmacological testing on these drugs is of limited usefulness. Early initiation of alternative therapy may be the preferred clinical option.