Fifty-one patients with symptomatic
ventricular tachycardia who failed control on current
anti-arrhythmics were studied. Seventy-four percent had
ischemic heart disease and 81% had
congestive heart failure. Patients underwent serial 24 Holter recordings and
radionuclide ventriculography before, during dose titration and during long-term
mexiletine therapy. Twenty-eight patients (55%) were successfully controlled. Of these, 17 (33%) remained controlled greater than or equal to 1 year. Early and late side effects were common but benign and included mostly gastric
pain and
nausea. Twenty-eight patients underwent
radionuclide ventriculography before and during
mexiletine therapy: there was no significant difference in heart rate, blood pressure, left ventricular ejection fraction, stroke volume and end-diastolic volumes before and during
mexiletine. Left ventricular ejection fraction was 21.4 +/- 2.2%, (SD) and 21.3 +/- 2.2% (SD) before and during
mexiletine respectively.
Digoxin blood levels measured in 15 patients were not significantly changed by
mexiletine. In conclusion,
mexiletine is effective and safe in many patients with intractable
ventricular tachycardia. It has no significant hemodynamic effects even in patients with
congestive heart failure nor does it affect
digoxin blood levels. Its usefulness is limited by a high incidence of gastric intolerance.