421 Acute and subacute endocarditis 
421.0 Acute and subacute bacterial endocarditis convert 421.0 to ICD-10-CM 421.1 Acute and subacute infective endocarditis in diseases classified elsewhere convert 421.1 to ICD-10-CM
421.9 Acute endocarditis unspecified convert 421.9 to ICD-10-CM