LAMC1 and cardiac arrhythmia: General basement membrane dysfunction implicated in cardiovascular pathologies including arrhythmia.99 Laminin (including LAMC1) protein levels differ in patients with and without atrial fibrillation.100, 101LAMC1 gene implicated in arrhythmia.102 Laminins (including LAMC1) important in regulation of heart looping, atrial growth and cardiac size during development.103LAMC1‐mutant cardiomyocyte cultures display impaired electrical signal propagation104