Learning ICD-10: Documenting Type 2 Myocardial Infarction

I am in the middle of a heads-down project, but I popped my head up long enough to read the new ICD-10-CM guidelines for 2018 (thanks for the notification, Gloryanne Bryant!). I had to take a moment to comment on the Type 2 myocardial infarction (MI) guidelines.

The reasons we should be documenting and coding conditions is for communicating with other clinicians, recognizing clinical significance and prognostication, and receiving appropriate compensation for utilization of resources. The implication that a Type 2 MI is different than a Type 1 MI and the new guidelines reflect this.

For a quick review:

  • Type 1 MI is myocardial necrosis, or cell death, caused by an anatomic blockage of blood flow for a prolonged period of time. This is usually due to atherosclerotic plaque and rupture or thrombosis, causing mechanical coronary artery obstruction.
  • Type 2 MI is also cell death, but in a non-anatomic distribution due to generalized hypoperfusion, on the basis of “supply-demand mismatch.” This means there is either an increase in demand (e.g., tachycardia) or a decrease in supply (e.g., hypotension). There is always an underlying condition or disease process that causes the Type 2 MI.
  • Ischemia means insufficient blood perfusion, and prolonged ischemia leads to infarction, i.e., cell death. When cells die and break down, they release their contents, including troponin, a heart-muscle protein. In general, once heart tissue dies, it does not regenerate and the patient develops scar tissue.

It is awesome that we finally have a unique code for Type 2 MI, I21.A1. It does not need artery site specification because that is not relevant. Its significance is that it imparts a more serious prognosis to the causative underlying condition.

A second Type 1 MI can either be reinfarction in the same anatomic distribution, as an extension of the first MI, or a patient can have another Type 1 MI in a different vessel, with a different area of the heart being affected.

Treatment of myocardial infarction has always been informed by the desire to prevent death, reinfarction, congestive heart failure, or other post-myocardial infarction complications (for which ICD-10-CM has given us the ability to codify and capture). Being able to detail reinfarction within 28 days as a “subsequent myocardial infarction” is key in being able to perform epidemiological research and hopefully find effective treatments. Being able to analyze data and effect changes in treatment and prognosis is also the basis for the acute MI (AMI) Core Measure Set.

However, Type 2 MI does not have the same course, prognosis, or treatment as Type 1 MI. Once the underlying condition is brought under control, the Type 2 MI resolves. Healthcare providers were gun-shy about calling out Type 2 MIs initially because the inability to code and separate out the condition caused them to fall out of the AMI Core Measures. Most facilities bypassed this problem by using “not indicated due to Type 2 MI” as an exclusion in their order set.

It is a non sequitur to have a subsequent Type 2 MI. Type 2 MI is related to flogging a heart on the basis of some other condition, not a direct reflection of the heart’s intrinsic health (although Type 2 MIs are more likely to occur in older patients with underlying generalized heart disease), and it is limited to the index admission. If one survives septic shock with a Type 2 MI, one might follow up with a cardiologist to rule out coronary artery and heart disease – which might respond to chronic treatment, but not for long-term treatment of the Type 2 MI, per se.

My favorite part of the new guidelines, however, has to be I.C.9.e.5, wherein it is specified that “MI due to demand ischemia or secondary to ischemic (im)balance” is assigned to Type 2 MI and not I24.8, Other forms of acute ischemic heart disease. I have seen coders disregard the “Type 2 MI” verbiage and only code the “due to demand ischemia” with I24.8. This does not capture the severity of illness or complexity of the patient. In fact, I have even seen institutions create internal guidelines that tie coders’ hands from coding and capturing the Type 2 MI. Internal guidelines should be revised in advance of Oct. 1, when the 2018 Official ICD-10-CM Guidelines go into effect.

The Guidelines also permit resolution of the conflict set up by documentation of “Type 2 NSTEMI” by instructing us to only pick up the Type 2 MI. All doctors who have been producing this hedgy documentation should thank the Centers for Disease Control and Prevention (CDC) for averting the onslaught of queries that otherwise would have been elicited.

Finally, hooray for gaining permission to sequence depending on the circumstances of an admission. A patient might present with a condition that otherwise would have been manageable as observation or outpatient, but the positive troponin elicited an admission and cardiac workup, only to ultimately reveal a Type 2 MI. Hindsight is 20-20, but the patient’s health and safety should be our primary focus. The Type 2 MI would meet the definition of a principal diagnosis and should be permitted to be sequenced first.

CDC and governing bodies, kudos on getting it right!

Back to work for me. Cheers!

Facebook
Twitter
LinkedIn

Erica Remer, MD, FACEP, CCDS, ACPA-C

Erica Remer, MD, FACEP, CCDS, ACPA-C has a unique perspective as a practicing emergency physician for 25 years, with extensive coding, CDI, and ICD-10 expertise. As physician advisor for University Hospitals Health System in Cleveland, Ohio for four years, she trained 2,700 providers in ICD-10, closed hundreds of queries, fought numerous DRG clinical determination and medical necessity denials, and educated CDI specialists and healthcare providers with engaging, case-based presentations. She transitioned to independent consulting in July 2016. Dr. Remer is a member of the ICD10monitor editorial board and is the co-host on the popular Talk Ten Tuesdays weekly, live Internet radio broadcasts.

Related Stories

United Health to Denial Claims Based on ICD-10

United Health to Deny Claims Based on Excludes1

UnitedHealthcare (UHC) Medicare Advantage will begin reinforcing denialsbased on its interpretation of the International Classification of Disease, 10 thEdition, Clinical Modification (ICD-10-CM) Excludes 1.(https://www.uhcprovider.com/content/dam/provider/docs/public/policies/medadv-reimbursement/rpub/UHC-MEDADV-RPUB-JAN-2026.pdf) As

Read More
H.R. 1 Impact on Coding

H.R. 1 Impact on Coding

H.R. 1 doesn’t directly rewrite ICD-10 or CPT, but it does change the environment in which you’re coding. The impact is mostly indirect – through

Read More

Leave a Reply

Please log in to your account to comment on this article.

Featured Webcasts

I022426_SQUARE

Fracture Care Coding: Reduce Denials Through Accurate Coding, Sequencing, and Modifier Use

Expert presenters Kathy Pride, RHIT, CPC, CCS-P, CPMA, and Brandi Russell, RHIA, CCS, COC, CPMA, break down complex fracture care coding rules, walk through correct modifier application (-25, -57, 54, 55), and clarify sequencing for initial and subsequent encounters. Attendees will gain the practical knowledge needed to submit clean claims, ensure compliance, and stay one step ahead of payer audits in 2026.

February 24, 2026
Mastering Principal Diagnosis: Coding Precision, Medical Necessity, and Quality Impact

Mastering Principal Diagnosis: Coding Precision, Medical Necessity, and Quality Impact

Accurately determining the principal diagnosis is critical for compliant billing, appropriate reimbursement, and valid quality reporting — yet it remains one of the most subjective and error-prone areas in inpatient coding. In this expert-led session, Cheryl Ericson, RN, MS, CCDS, CDIP, demystifies the complexities of principal diagnosis assignment, bridging the gap between coding rules and clinical reality. Learn how to strengthen your organization’s coding accuracy, reduce denials, and ensure your documentation supports true medical necessity.

December 3, 2025

Proactive Denial Management: Data-Driven Strategies to Prevent Revenue Loss

Denials continue to delay reimbursement, increase administrative burden, and threaten financial stability across healthcare organizations. This essential webcast tackles the root causes—rising payer scrutiny, fragmented workflows, inconsistent documentation, and underused analytics—and offers proven, data-driven strategies to prevent and overturn denials. Attendees will gain practical tools to strengthen documentation and coding accuracy, engage clinicians effectively, and leverage predictive analytics and AI to identify risks before they impact revenue. Through real-world case examples and actionable guidance, this session empowers coding, CDI, and revenue cycle professionals to shift from reactive appeals to proactive denial prevention and revenue protection.

November 25, 2025
Sepsis: Bridging the Clinical Documentation and Coding Gap to Reduce Denials

Sepsis: Bridging the Clinical Documentation and Coding Gap to Reduce Denials

Sepsis remains one of the most frequently denied and contested diagnoses, creating costly revenue loss and compliance risks. In this webcast, Angela Comfort, DBA, MBA, RHIA, CDIP, CCS, CCS-P, provides practical, real-world strategies to align documentation with coding guidelines, reconcile Sepsis-2 and Sepsis-3 definitions, and apply compliant queries. You’ll learn how to identify and address documentation gaps, strengthen provider engagement, and defend diagnoses against payer scrutiny—equipping you to protect reimbursement, improve SOI/ROM capture, and reduce audit vulnerability in this high-risk area.

September 24, 2025

Trending News

Featured Webcasts

Top 10 Audit Targets for 2026-2027 for Hospitals & Physicians: Protect Your Revenue

Stay ahead of the 2026-2027 audit surge with “Top 10 Audit Targets for 2026-2027 for Hospitals & Physicians: Protect Your Revenue,” a high-impact webcast led by Michael Calahan, PA, MBA. This concise session gives hospitals and physicians clear insight into the most likely federal audit targets, such as E/M services, split/shared and critical care, observation and admissions, device credits, and Two-Midnight Rule changes, and shows how to tighten documentation, coding, and internal processes to reduce denials, recoupments, and penalties. Attendees walk away with practical best practices to protect revenue, strengthen compliance, and better prepare their teams for inevitable audits.

January 29, 2026

AI in Claims Auditing: Turning Compliance Risks into Defensible Systems

As AI reshapes healthcare compliance, the risk of biased outputs and opaque decision-making grows. This webcast, led by Frank Cohen, delivers a practical Four-Pillar Governance Framework—Transparency, Accountability, Fairness, and Explainability—to help you govern AI-driven claim auditing with confidence. Learn how to identify and mitigate bias, implement robust human oversight, and document defensible AI review processes that regulators and auditors will accept. Discover concrete remedies, from rotation protocols to uncertainty scoring, and actionable steps to evaluate vendors before contracts are signed. In a regulatory landscape that moves faster than ever, gain the tools to stay compliant, defend your processes, and reduce liability while maintaining operational effectiveness.

January 13, 2026
Surviving Federal Audits for Inpatient Rehab Facility Services

Surviving Federal Audits for Inpatient Rehab Facility Services

Federal auditors are zeroing in on Inpatient Rehabilitation Facility (IRF) and hospital rehab unit services, with OIG and CERT audits leading to millions in penalties—often due to documentation and administrative errors, not quality of care. Join compliance expert Michael Calahan, PA, MBA, to learn the five clinical “pillars” of IRF-PPS admissions, key documentation requirements, and real-life case lessons to help protect your revenue.

November 13, 2025

Trending News

Prepare for the 2025 CMS IPPS Final Rule with ICD10monitor’s IPPSPalooza! Click HERE to learn more

Get 15% OFF on all educational webcasts at ICD10monitor with code JULYFOURTH24 until July 4, 2024—start learning today!

CYBER WEEK IS HERE! Don’t miss your chance to get 20% off now until Dec. 1 with code CYBER25

CYBER WEEK IS HERE! Don’t miss your chance to get 20% off now until Dec. 2 with code CYBER24