When the conduction disturbance expresses a cardiomyopathy.

Electrocardiogram may play a crucial role in the diagnostic workup of different cardiomyopathies. Electrocardiogram abnormalities in impulse generation and transmission may be an early marker of these insidious pathologies. Some findings are suggestive of definite disorders, and other findings are less sensitive and/or specific, but may orient towards a specific diagnosis in a patient with a peculiar phenotype. Electrocardiogram findings not only could help to early recognize affected patients but may also have an important prognostic role in evaluating disease evolution over time and identifying patients at higher risk of sudden cardiac death. Electrocardiogram reading and the careful interpretation of its features remain a cornerstone for orienting the diagnosis towards specific forms and provide useful tools for risk stratification.