Isolated Inferior Infarction (Mid RCA)

What this page documents

This page describes the hemodynamic and spatial parameterization of the computational mid right coronary artery occlusion model (RCA_MID) integrated into MioAtlas. It precisely sets out perfusion geometric coefficients, compromised myocardial segments according to standard tomographic segmentation, and electrocardiographic projection rules for diaphragmatic leads. This content is technical software and computational simulation documentation; it does not constitute clinical practice guidelines or care protocols for real patients.

Model parameters

Numerical and topological values assigned to the RCA_MID entity in the coronary catalog (src/coronaries/catalog.ts) are structured into the following parameters:

Source of each parameter value

Anatomical boundaries and vector projections for this entity are supported by the following scientific consensuses:

1. Definition of transmural necrosis and ST shifts: Pathological J-point elevation thresholds in inferior leads (≥ 0.1 mV in contiguous leads II, III, and aVF) and reciprocal changes in I and aVL follow criteria from the Fourth Universal Definition of Myocardial Infarction (Thygesen et al., 2018).
2. Territorial distribution and lead correlations: Inferior lead ECG manifestations and correlation with mid RCA occlusion align with AHA/ACCF/HRS recommendations in Wagner et al. (2009).
3. Myocardial segment nomenclature (segments 4, 10, and 15): Assignment of basal, mid, and apical inferior walls to the distal RCA territory in right dominance adheres strictly to the 17-segment model of Cerqueira et al. (2002).
4. Monitor calibration and vector registration: Standard visual grid display at 25 mm/s and 10 mm/mV satisfies instrumentation standards documented by Kligfield et al. (2007).

How it is modeled

Upon selecting RCA_MID, the coronary engine establishes a complete occlusion at mid-length of the right coronary artery (offsetFactor = 0.52). Located distal to the origins of right ventricular branches, the right ventricle maintains preserved perfusion, isolating acute ischemia exclusively to the diaphragmatic wall of the left ventricle.

The ischemic ellipsoid induces a transmembrane potential difference during phase 4 and phase 2 of the action potential across segments 4, 10, and 15. This injury vector points inferiorly and rightward (+120° in the frontal plane), generating prominent ST elevation in lead III (greater than in II), ST elevation in aVF, and reciprocal depression in opposing lateral leads (I and aVL). The 3D myocardial mesh renders real-time violaceous coloring across the hypoperfused zone.

What is NOT reproduced

The simulator focuses on macroscopic anatomical-electrical correlation. The following complex phenomena are explicitly omitted:

• Mechanical valvular complications: Posteromedial papillary muscle ischemic necrosis and acute severe mitral regurgitation are not calculated in pressure hemodynamic equations.
• Reflex atrioventricular block induction: In real patients with right dominance, proximal or mid occlusion can compromise the AV nodal artery at the crux; the simulator maintains independent baseline rhythm without spontaneous bradycardia or AV block unless manually triggered.
• Dynamic collateral circulation: Protective retrograde septal collateral flow from the left anterior descending artery (Rentrop classification) is not modeled.
• No-reflow phenomenon: Microvascular reperfusion injury following virtual percutaneous transluminal angioplasty is not simulated.

Interactive variants

Explore different hemodynamic conditions and anatomical variants preconfigured in the simulator:

• Mid RCA Occlusion in Right Dominance: Classic inferior pattern with ST elevation in II, III, and aVF (III > II) and reciprocal depression in I and aVL.
• Mid RCA Occlusion in Left Dominance: Hypoplastic right coronary artery; inferior wall perfused by the circumflex, yielding minimal inferior ECG changes.
• Hyperacute Phase of Inferior Infarction: Prominent, widened T waves with incipient J-point elevation.
• Established Phase with Pathological Q Waves: Frank tissue necrosis with pathological Q waves > 30 ms in inferior leads and T-wave inversion.

Related entities to compare in the simulator

To contrast this territory with alternative right and left coronary occlusions in the 3D viewer:

• Proximal RCA Inferior Infarction with RV Involvement: Occlusion proximal to ventricular branches with elevation in V3R and V4R.
• Posterior Descending Artery (PDA) Occlusion Infarction: Ischemia confined to the basal and middle third of the posterior interventricular groove.
• Inferolateral Infarction via Proximal Circumflex Occlusion: ST elevation in II > III, aVF, and low lateral (V5-V6) or posterior leads (V7-V9).
• Aslanger Pattern in Mid RCA Territory: Inferior infarction in multivessel disease with isolated elevation in lead III and widespread precordial depression.