Lamotrigine-trigged obstructive hypertrophic cardiomyopathy, epilepsy and metabolic myopathy

Lamotrigine has the advantage to have an antidepressive effect and to be well tolerated in the majority of the cases. Lamotrigine, however, may exert cardiac side effects in patients with hypertrophic cardiomyopathy and latent obstruction of the left ventricular outflow tract, as illustrated by the following case report. In a 67 year-old male with epilepsy, metabolic myopathy and malignant hyperthermia hypertrophic cardiomyopathy was diagnosed by echocardiography. By Doppler-echocardiography the maximal gradient in the left ventricular outflow tract was 57 mm Hg. Because or recurrent seizures, the lamotrigine dosage was increased from 100 mg/d to 200 mg and then to 300 mg/d. After the first intake of 300 mg lamotrigine, the patient felt weak, dizzy and complained about exertional dyspnoea and chest pain. Doppler-echocardiography showed now a maximal gradient of 106 mm Hg in the left ventricular outflow tract. After reducing the lamotrigine dosage to 100 mg/d and adding levetirazetam (1000 mg/d), the patient's condition improved immediately and the outflow-tract-gradient regressed to 12 mm Hg. Cardiac catheterization showed an outflow-tract-gradient of 25-36 mm Hg and normal coronary arteries. From this observation we conclude that care should be taken when prescribing lamotrigine to patients with obstructive hypertrophic cardiomyopathy.