Chapter 9

I00–I99: Diseases of the Circulatory System

Diseases of the Circulatory System diagnostic classification updated for 2026.

Chapter Instructions

Excludes2(Not included here. Code separately if applicable.)

certain conditions originating in the perinatal period (P04-P96)
certain infectious and parasitic diseases (A00-B99)
complications of pregnancy, childbirth and the puerperium (O00-O9A)
congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)
endocrine, nutritional and metabolic diseases (E00-E88)
injury, poisoning and certain other consequences of external causes (S00-T88)
neoplasms (C00-D49)
symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)
systemic connective tissue disorders (M30-M36)
transient cerebral ischemic attacks and related syndromes (G45.-)

All Codes Billable Only

Internal Codes

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I50.812|
Chronic right heart failure
I50.813|
Acute on chronic right heart failure
I50.814|
Right heart failure due to left heart failure
I50.82|
Biventricular heart failure
I50.83|
High output heart failure
I50.84|
End stage heart failure
I50.89|
Other heart failure
I50.9|
Heart failure, unspecified
I51.0|
Cardiac septal defect, acquired
I51.1|
Rupture of chordae tendineae, not elsewhere classified
I51.2|
Rupture of papillary muscle, not elsewhere classified
I51.3|
Intracardiac thrombosis, not elsewhere classified
I51.4|
Myocarditis, unspecified
I51.5|
Myocardial degeneration
I51.7|
Cardiomegaly
I51.81|
Takotsubo syndrome
I51.89|
Other ill-defined heart diseases
I51.9|
Heart disease, unspecified
I52|
Other heart disorders in diseases classified elsewhere
I5A|
Non-ischemic myocardial injury (non-traumatic)
I60.00|
Nontraumatic subarachnoid hemorrhage from unspecified carotid siphon and bifurcation
I60.01|
Nontraumatic subarachnoid hemorrhage from right carotid siphon and bifurcation
I60.02|
Nontraumatic subarachnoid hemorrhage from left carotid siphon and bifurcation
I60.10|
Nontraumatic subarachnoid hemorrhage from unspecified middle cerebral artery
I60.11|
Nontraumatic subarachnoid hemorrhage from right middle cerebral artery
I60.12|
Nontraumatic subarachnoid hemorrhage from left middle cerebral artery
I60.2|
Nontraumatic subarachnoid hemorrhage from anterior communicating artery
I60.30|
Nontraumatic subarachnoid hemorrhage from unspecified posterior communicating artery
I60.31|
Nontraumatic subarachnoid hemorrhage from right posterior communicating artery
I60.32|
Nontraumatic subarachnoid hemorrhage from left posterior communicating artery
I60.4|
Nontraumatic subarachnoid hemorrhage from basilar artery
I60.50|
Nontraumatic subarachnoid hemorrhage from unspecified vertebral artery
I60.51|
Nontraumatic subarachnoid hemorrhage from right vertebral artery
I60.52|
Nontraumatic subarachnoid hemorrhage from left vertebral artery
I60.6|
Nontraumatic subarachnoid hemorrhage from other intracranial arteries
I60.7|
Nontraumatic subarachnoid hemorrhage from unspecified intracranial artery
I60.8|
Other nontraumatic subarachnoid hemorrhage
I60.9|
Nontraumatic subarachnoid hemorrhage, unspecified
I61.0|
Nontraumatic intracerebral hemorrhage in hemisphere, subcortical
I61.1|
Nontraumatic intracerebral hemorrhage in hemisphere, cortical
I61.2|
Nontraumatic intracerebral hemorrhage in hemisphere, unspecified
I61.3|
Nontraumatic intracerebral hemorrhage in brain stem
I61.4|
Nontraumatic intracerebral hemorrhage in cerebellum
I61.5|
Nontraumatic intracerebral hemorrhage, intraventricular
I61.6|
Nontraumatic intracerebral hemorrhage, multiple localized
I61.8|
Other nontraumatic intracerebral hemorrhage
I61.9|
Nontraumatic intracerebral hemorrhage, unspecified
I62.00|
Nontraumatic subdural hemorrhage, unspecified
I62.01|
Nontraumatic acute subdural hemorrhage
I62.02|
Nontraumatic subacute subdural hemorrhage

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