What is the serious heart condition characterized by blocked impulses from atria to ventricles?

The serious heart condition characterized by blocked impulses from the atria to the ventricles is known as third-degree heart block. In this condition, there is a complete interruption in the electrical signals that normally travel from the atria to the ventricles. This means that the atria can beat independently from the ventricles, leading to a situation where the heart is not effectively coordinating its contractions.

Third-degree heart block can result in significant symptoms such as fatigue, dizziness, or even loss of consciousness, due to the inadequate blood flow from an uncoordinated heartbeat. The ventricles may respond by beating at a slower rate, which is often insufficient to maintain proper circulation. This condition requires immediate medical attention, often necessitating the implantation of a pacemaker to restore normal electrical conduction.

First-degree heart block typically presents as a delay in the conduction system, without complete blockage. Second-degree heart block is characterized by intermittent failure of some impulses to conduct to the ventricles, resulting in dropped beats but not a complete block. Atrial fibrillation is an arrhythmia where the atria quiver and fail to contract effectively, but it does not involve a complete blockage between the atria and ventricles.