EFFICACY OF COMBINATION THERAPY WITH MEXILETINE AND A LOW-DOSE OF PROPRANOLOL FOR PREMATURE VENTRICULAR ARRHYTHMIAS

The clinical efficacy of combination therapy with mexiletine and propranolol was investigated in several centres. Twenty-four-hour Holter electrocardiograms were recorded and the severity of ventricular premature beats (VPBs) was assessed on the basis of the frequency of VPBs and according to the criteria of Lown. Forty-eight cases with VPBs received single treatment with mexiletine (300 mg/day). Single treatment with mexiletine was effective in 26 out of 48 cases (54%). Nineteen cases in which the single treatment with mexiletine was not sufficiently effective received combintion therapy with mexiletine (300 mg/day) and a low dose of propranolol (30 mg/day). After the combination therapy, significant decreases in the frequency of VPBs were found in 11 out of 19 cases (58%), and lowering of the severity of the grade was found in 4 cases (30.8%). Thirteen out of 19 cases given combination therapy changed to single treatment with propranolol. A change in treatment from combination therapy to single treatment with propranolol was assessed as "undesirable" in 8 out of 13 cases (61.5%). During single treatment with mexiletine, side effects were found in 1 out of 48 cases (2.1%), and during the combination therapy in 1 out of 19 cases (5.2%). Thus, combination therapy with mexiletine and a low dose of propranolol was shown to be useful for patients with VPBs.