Resolution of Refractory Multifocal Atrial Tachycardia in Costello Syndrome Using Trametinib: A Case Supporting MEK Inhibitors as Targeted, Specific Antiarrhythmic.
Vanina Taliercio, Annabelle Wilcox, Stacey Cole et al.
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Case in brief
An infant with Costello syndrome and a pathogenic HRAS variant presented with drug-refractory multifocal atrial tachycardia (MAT). After multiple antiarrhythmic therapies failed, trametinib was initiated, leading to rapid resolution of MAT and allowing for the gradual discontinuation of other medications. MAT did not recur after trametinib was stopped, although the patient later developed hypertrophic cardiomyopathy.
What made this case unusual
The case highlights the potential disease-modifying cardioprotective effect of trametinib, as hypertrophic cardiomyopathy developed only after discontinuation of the MEK inhibitor.
Diagnostic / clinical pearl
Clinicians should consider MEK inhibitors like trametinib as a targeted antiarrhythmic option in patients with Costello syndrome experiencing refractory atrial tachycardia.
Why it matters
This case suggests that MEK inhibition may provide not only acute rhythm control but also long-term cardiac protection in patients with Costello syndrome.