2008 ICD-9-CM Volume 1 Diagnosis Codes Home > Diseases Of The Circulatory System 390-459 > Other Forms Of Heart Disease 420-429 > Cardiac Dysrhythmias 427.* > 2008 ICD-9-CM Diagnosis 427.31 Atrial fibrillation  On October 1, 2008 the 2009 ICD-9-CM codes came into effect. Therefore, this code may be out of date. The 2009 version of ICD-9-CM 427.31 can be accessed here. Disorder of cardiac rhythm characterized by rapid, irregular atrial impulses and ineffective atrial contractions. 427.31 is a specific code that can be used to specify a diagnosis 427.31 contains 2 index entries View the ICD-9-CM Volume 1 427.* hierarchy ICD9Data's sister site ProcedureCodes.com launches with the 2008/09 CPT® codes - read more on the ICD9Data.com blog. Index entries containing 427.31: Fibrillation atrial (established) (paroxysmal) 427.31 auricular (atrial) (established) 427.31