Home > Heart Disease > Heart block Get the Flash Player to see this player. Rate: (Click the stars to rate) Published on Jul 20, 2008 by TMattioni, Views: 2292 Heart block is a type of bradycardia (slow heart rate) that occurs when the electrical signals that stimulate heart muscle contractions are partially or totally blocked. Heart block occurs when the beat that originates in the upper chambers of the heart is unable to pass to the lower chambers of the heart. Common symptoms are light headedness, shortness of breath, palpitations, chest pain, and syncope, or passing out. Treatment is usually a pacemaker.