The change in classification of cardiomyopathies — diseases that can affect the function of the heart and, if progressive, may lead to heart failure — from one that is disease-based to one that is infested with echocardiogram findings, is a step backward in time and contrary to the intent of the International Classification of Diseases.  Currently, the ICD-10 model lists the following:

I42 Cardiomyopathy
Includes: myocardiopathy
Code first pre-existing cardiomyopathy complicating pregnancy and puerperium (O99.4)
Excludes1: ischemic cardiomyopathy (I25.5)
peripartum cardiomyopathy (O90.3)
Excludes2: ventricular hypertrophy (I51.7)

 I42.0 Dilated cardiomyopathy
Congestive cardiomyopathy

 I42.1 Obstructive hypertrophic cardiomyopathy
Hypertrophic subaortic stenosis (idiopathic)

 I42.2 Other hypertrophic cardiomyopathy
Nonobstructive hypertrophic cardiomyopathy

 I42.3 Endomyocardial (eosinophilic) disease
Endomyocardial (tropical) fibrosis
Löffler’s endocarditis

I42.4 Endocardial fibroelastosis
Congenital cardiomyopathy

I42.5 Other restrictive cardiomyopathy
Constrictive cardiomyopathy NOS

I42.6Alcoholic cardiomyopathy
Code also presence of alcoholism (F10.-)

I42.7Cardiomyopathy due to drug and external agent
Code first poisoning due to drug or toxin, if applicable (T36-T65 with fifth or sixth character 1-4 or 6)
Use additional code for adverse effect, if applicable, to identify drug (T36-T50 with fifth or sixth character 5)

I42.8 Other cardiomyopathies

I42.9 Cardiomyopathy, unspecified
Cardiomyopathy (primary) (secondary) NOS

I43 Cardiomyopathy in diseases classified elsewhere
Code first underlying disease, such as:
    amyloidosis (E85.-)
    glycogen storage disease (E74.0)
    gout (M10.0-)
    thyrotoxicosis (E05.0E05.9-)
Excludes1: cardiomyopathy (in):
    coxsackie (virus) (B33.24)
    diphtheria (A36.81)
    sarcoidosis (D86.85)
    tuberculosis (A18.84)

Hypertensive Cardiomyopathy is not addressed at all in the index. To be consistent with the coding of this entity in ICD-9 it should be as follows:

I11.0 Hypertensive heart disease with heart failure plus I43 Cardiomyopathy in diseases classified elsewhere

I11.9 Hypertensive heart disease without heart failure plus I43 Cardiomyopathy in diseases classified elsewhere

I13.0 – I13.2 series Hypertensive heart and renal disease with or without heart failure and with CKD stages 1-4 or 5 and ESRD

I25.5 Ischemic cardiomyopathy (no longer ischemic heart disease as 414.8 has been defined in ICD-9

O90.3 Peripartum cardiomyopathy

My contention is that codes for “cardiomyopathy” are intended to identify a disease process that can cause damage to function of the heart. That’s what ICD is all about, isn’t it?  So to put in codes for what a heart looks like on an echocardiogram and state that this is a disease is ludicrous.

First, equating dilated cardiomyopathy with congestive cardiomyopathy is wrong.  Dilated cardiomyopathies most often result in systolic dysfunction and congestion of the lungs is a diastolic manifestation (inability to fill the left ventricle, whether due to weak emptying or inadequate filling).  So this is inappropriate.

Next, as you can see, there are no specific codes for primary cardiomyopathy, an inherent problem in the heart muscle not caused by something else (that we know of yet) and probably often genetic and, in the past, 425.4 was the most frequently reported cardiomyopathy in the United States.  This is probably because the advice on how to use it was totally wrong, but that’s beside the point.  We no longer have a way to identify primary disease of the heart muscle with the exception of I42.9 that lumps primary in with secondary and calls them both unspecified where it IS specified as primary.  What????

In adults, the most common cause of dilated hearts is ischemic disease of the heart muscle.  We also see alcoholic cardiomyopathy, diabetic (microischemic) cardiomyopathy as well as infections and terminal hypertensive disease.  In children, we have valvular problems and viral myocarditis and chemotherapy—induced dilation of the heart — but if we know what the cause is, there are other codes for that than I42.0. 

In pregnancy, dilation of the heart may well be represented by peripartum cardiomyopathy – and there is a code for that. I42.0 is a useless code and will do nothing but inhibit the physician’s desire to document causation of a dilated heart and that is counterproductive to knowing what’s wrong with our patients. If the doc truly doesn’t know what is causing a dilated heart, it would be more honest and clinically more pertinent to use I42.9, cardiomyopathy I don’t have any idea what it is.

Certainly, in children, dilated hearts are probably the most frequent presentation of the heart’s response to a disease process. Most of the dilated cardiomyopathy cases are idiopathic, which means a workup was done and no cause was identifiable – so let’s get a code for idiopathic cardiomyopathy (which we’ve never had). After that, we have the viral myocarditis group, genetic dilations (no code for that) and autoimmunity. I mean, if the doc knows what the cause is, a code should be assigned for that cause – and not “dilated cardiomyopathy.”  And if the doc doesn’t know what the cause is, it should be identified as idiopathic (workup revealed no specific known cause but we know that it is unidentifiable by usual means) or “I don’t know what it is” period.

Next, we have I42.5 for other restrictive cardiomyopathy, another echocardiographic finding. Why do they say “other?” Because such diseases as amyloidosis of the heart causes very severe restriction of heart muscle action and the worst diastolic failure you can have. Ischemia may cause restriction of motion because of scarring. Hemochromatosis, sarcoid, radiation can cause restrictive hearts – and they all have direction on how to assign specific codes for them.

Restriction is found in children in scleroderma, Gaucher’s disease, Hypereosinophilic syndrome and other diseases, but they are all cardiomyopathies in diseases classified elsewhere and have a code set.

A way out of this morass is to perhaps designate as ICD-10 code I42.90 for idiopathic dilated cardiomyopathy, I42.91 for idiopathic restrictive cardiomyopathy, I42.92 for idiopathic other cardiomyopathy not identified as dilated or restrictive and I42.99 for undefined cardiomyopathy.  At least that would be honest.

Oh, and as long as we’re at it, I42.1 and I42.2 are the same disease with varying severities of hypertrophy and blockage of left ventricular outflow. Why should these not be represented by I42.10 and I42.11 or I42.18 as it was in ICD-9? All other diseases with varying manifestations are listed under the same heading everywhere else. 

This is contrary to ICD logic and should be fixed.

About the Author

Robert S. Gold, MD, is a nationally known physician, responsible for having championed clinical documentation with a peer-to-peer educational approach in hospital organizations. Dr. Gold is a cofounder and the CEO for DCBA, Inc., a consulting firm that concentrates on development of Clinical Documentation Improvement (CDI) programs that aid in proper data streams, proper communication within the medical records and proper reimbursement.

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