First-degree heart block: The electrical signals are slowed, but all signals still reach the ventricles. This is typically less severe and often asymptomatic. Second-degree heart block: Some of the electrical signals do not reach the ventricles. This can be further categorized into Mobitz Type I and Mobitz Type II. Third-degree heart block: Also known as complete heart block, this is the most severe form. None of the electrical signals from the atria reach the ventricles, leading to a completely independent and typically slower ventricular rhythm.
