What is the normal AH?

What is the normal AH?

• A. 30-70
• B. 40-80
• C. 60-140
• D. 50-120

Answer: (D)

The AH interval measures the time it takes for an electrical impulse to travel from the atrium to the His bundle, reflecting conduction through the AV node. In a typical electrophysiology study, this interval is about 50 to 120 milliseconds. This range represents normal AV nodal conduction. If the AH interval is longer than this, it suggests AV nodal delay or disease; if it’s shorter, AV nodal conduction is relatively fast. The other ranges listed fall outside the usual normal window, whereas 50–120 ms sits right in the expected span. Therefore, the normal AH is approximately 50–120 ms.

The AH interval measures the time it takes for an electrical impulse to travel from the atrium to the His bundle, reflecting conduction through the AV node. In a typical electrophysiology study, this interval is about 50 to 120 milliseconds. This range represents normal AV nodal conduction. If the AH interval is longer than this, it suggests AV nodal delay or disease; if it’s shorter, AV nodal conduction is relatively fast. The other ranges listed fall outside the usual normal window, whereas 50–120 ms sits right in the expected span. Therefore, the normal AH is approximately 50–120 ms.