Consistent PR blocks are described as including which block types?

Consistent PR blocks are described as including which block types?

• A. 3rd Degree Block
• B. 2nd Degree Type 1
• C. 1st Degree Block and 2nd Degree Type 2
• D. 1st Degree Only

Answer: (C)

Patterns with a consistent PR block mean the conduction timing from atria to ventricles stays regular across beats. The only patterns that keep that stable PR timing while still showing block features are the first-degree block, where the PR interval is prolonged but constant for every beat, and Mobitz II (second-degree type 2), where the PR interval before each conducted beat remains unchanged and occasionally a beat is dropped. Together, these describe consistent PR blocks. In contrast, Wenckebach (second-degree type 1) shows a gradually lengthening PR interval until a beat drops, so the PR timing isn’t consistent. Third-degree block involves complete AV dissociation with no fixed relationship between P waves and QRS, so it isn’t a PR block pattern at all.

Patterns with a consistent PR block mean the conduction timing from atria to ventricles stays regular across beats. The only patterns that keep that stable PR timing while still showing block features are the first-degree block, where the PR interval is prolonged but constant for every beat, and Mobitz II (second-degree type 2), where the PR interval before each conducted beat remains unchanged and occasionally a beat is dropped. Together, these describe consistent PR blocks. In contrast, Wenckebach (second-degree type 1) shows a gradually lengthening PR interval until a beat drops, so the PR timing isn’t consistent. Third-degree block involves complete AV dissociation with no fixed relationship between P waves and QRS, so it isn’t a PR block pattern at all.