Which type of heart block is associated with a progressively lengthened PR interval followed by a dropped beat?

The type of heart block characterized by a progressively lengthened PR interval followed by a dropped beat is 2nd degree heart block type 1, also known as Wenckebach or Mobitz type I. This arrhythmia occurs when there is a block in the conduction pathway through the AV node, resulting in the gradual prolongation of the PR interval with each successive heartbeat until a beat is dropped.

In this type of block, the cycle then resets, starting over with a normal PR interval for the next beat. The distinguishing feature of 2nd degree heart block type 1 is this pattern of progressive prolongation followed by a failure to conduct one of the impulses, leading to a missing QRS complex.

Understanding this pattern is crucial for recognizing the symptoms and implications of the block, allowing for appropriate management and intervention in a clinical setting.