2006 ICD-9-CM Volume 1 Diagnosis Codes Home > Diseases Of The Circulatory System 390-459 > Other Forms Of Heart Disease 420-429 > ICD-9-CM Diagnosis 421 Acute and subacute endocarditis 421 is a non-specific code that cannot be used to specify a diagnosis ICD-9-CM Diagnosis 421.0 Acute and subacute bacterial endocarditis Infection of the endocardium caused by species of STREPTOCOCCUS. This condition does not produce metastatic foci and if untreated may take up to a year to be fatal. 421.0 is a specific code that can be used to specify a diagnosis 421.0 contains 30 index entries ICD-9-CM Diagnosis 421.1 Acute and subacute infective endocarditis in diseases classified elsewhere 421.1 is a specific code that can be used to specify a diagnosis 421.1 contains 6 index entries ICD-9-CM Diagnosis 421.9 Acute endocarditis unspecified 421.9 is a specific code that can be used to specify a diagnosis 421.9 contains 8 index entries