The invention provides methods for inhibiting cardiomyopathy and for inhibiting cardiac arrhythmia, by administering to an individual in need thereof a cis-epoxyeicosantrienoic acid, an inhibitor of soluble epoxide hydrolase (sEH), or both. In some embodiments, the method comprises administering to the individual a nucleic acid encoding an inhibitor of sEH. Cardiomyopathies treatable by the methods of the invention include cardiac hypertrophy and dilated cardiomyopathy.