ACADL and cardiac rhythm disease: Patients with a deficiency in very long-chain acyl-CoA dehydrogenase (VLCAD; EC 1.3.99.3), the enzyme catalyzing the first step of the mitochondrial beta-oxidation of long-chain fatty acids (Houten and Wanders, 2010; Knottnerus et al., 2018), are at risk for developing liver, skeletal, and heart muscle dysfunction (Ribas and Vargas, 2020; Wanders et al., 2020), including cardiac arrhythmias (Bonnet et al., 1999).