Lacosamide is an antiepileptic drug that is used to treat partial-onset seizures in adults. While it is generally considered safe, there are potential risks associated with its use, particularly in relation to the heart.

According to Drug Patent Watch [1], one of the potential side effects of lacosamide is a disturbance in the heart's rhythm, which can lead to arrhythmias. The site notes that the drug's label includes a warning about the risk of cardiac events, and recommends that patients with pre-existing heart conditions be closely monitored while taking the medication.

The Mayo Clinic [2] also lists cardiac arrhythmias as a potential side effect of lacosamide, and notes that patients who experience symptoms such as palpitations, dizziness, or fainting should seek medical attention immediately. The site recommends that patients with a history of heart disease or abnormal heart rhythms be closely monitored while taking the medication.

A systematic analysis and review of the literature published in Cureus [3] found that lacosamide can cause a variety of cardiac arrhythmias, including sinus bradycardia, atrial fibrillation, and ventricular tachycardia. The study notes that while the incidence of these events is relatively low, they can be serious and require medical intervention.

In summary, lacosamide can cause disturbances in the heart's rhythm, which can lead to potentially serious cardiac events. Patients with pre-existing heart conditions or abnormal heart rhythms should be closely monitored while taking the medication, and should seek medical attention if they experience symptoms such as palpitations, dizziness, or fainting.

Sources:
[1] https://www.drugpatentwatch.com/p/tradename/LACOSAMIDE
[2] https://www.mayoclinic.org/drugs-supplements/lacosamide-oral-route/side-effects/drg-20072409?p=1
[3] https://www.cureus.com/articles/80198-lacosamide-related-arrhythmias-a-systematic-analysis-and-review-of-the-literature