Cardiology Coding Alert

Beware: You won't see identical ICD-9 and ICD-10 inclusion lists.

When you code Wolff-Parkinson-White (WPW) syndrome under ICD-10, you might be surprised to see a code definition that doesn't match the one you know under ICD-9.

ICD-9 code: WPW falls under 426.7 (Anomalous atrioventricular excitation) in ICD-9. Anomalous atrioventricular excitation is a heart rhythm disorder. In WPW, the patient has an extra electrical pathway which can cause rapid heart rate.

Notes in ICD-9 tell you that 426.7 is appropriate for the following:

• Atrioventricular conduction:

• Ventricular pre-excitation
• Wolff-Parkinson-White syndrome.

ICD-10 code: When you start using ICD-10 in 2013, you'll find WPW listed under I45.6 (Pre-excitation syndrome).

According to a note with I45.6, the code is appropriate for:

• Accelerated atrioventricular conduction
• Accessory atrioventricular conduction
• Anomalous atrioventricular excitation
• Lown-Ganong-Levine syndrome
• Pre-excitation atrioventricular conduction
• Wolff-Parkinson-White syndrome.

Note that ICD-10 includes Lown-Ganong-Levine syndrome in I45.6, the same code that applies to WPW and other pre-excitation syndromes. ICD-9 instead gives Lown-Ganong-Levine its own code (426.81, Lown-Ganong-Levine syndrome).

Coder tips: This code offers a good reminder of why it's important to search your diagnosis in the ICD-10 index and confirm the code in the tabular list, rather than working straight from ICD-9 to ICD-10 conversion lists. The "includes" lists may not be identical under similar ICD-9 and ICD-10 codes, so be sure you've got the best code for your case.

Remember: When ICD-10 goes into effect on Oct. 1, 2013, you should apply the code set and official guidelines in effect for the date of service reported. Learn more at www.cms.gov/ICD10/ and www.cdc.gov/nchs/icd/icd10cm.htm#10update.