ECG criteria
- ST-segment elevation in lead III, typically less than 1 mm, with no ST elevation in lead II
- ST changes in aVF are possible but are not an independent mandatory condition for the pattern
- ST depression in V4–V6, typically horizontal or downsloping; severity and distribution are evaluated in the context of the other criteria
- ST in V1 is isoelectric or elevated and positioned higher than ST in V2; isolated relative inequality with depression in both leads is not considered a criterion
- The ECG does not meet standard criteria for diagnostically significant ST elevation for STEMI
- Often a baseline-altered ECG (RBBB, hypertrophy, prior inferior scar), which may additionally mask the typical picture, but is not a mandatory condition for the pattern
What it looks like on ECG
The pattern consists of a combination of several leads and must be evaluated as a unified picture rather than by a single feature.
| Lead | Typical change |
|---|---|
| III | ST elevation, usually less than 1 mm |
| II | without ST elevation (key difference from typical inferior STEMI) |
| aVF | changes are possible, but not mandatory |
| V1 | ST is isoelectric or elevated, positioned higher than in V2 |
| V4–V6 | ST depression, often horizontal or downsloping |
| aVR | sometimes minor ST elevation |
Key logic: in typical inferior STEMI, ST elevation is usually present in two or more contiguous inferior leads — II, III, and/or aVF; diagnostic elevation in III and aVF without elevation in II is possible. The absence of elevation in II with elevation in III is a characteristic feature of the Aslanger pattern, rather than merely greater prominence of changes in III compared to II. Against this background, ST depression is identified in chest leads V4–V6, which upon quick inspection is easily interpreted as diffuse multi-vessel subendocardial ischemia, even though it may conceal a focal occlusion of the inferior wall. The ST ratio in V1 (isoelectric or elevated, higher than in V2) is a supportive sign helping to distinguish the picture from typical anterior ischemia; if ST is depressed in both leads, mere relative predominance in V1 is not considered a criterion. The amplitudes of ST changes are generally small (tenths of a millimeter up to about 1 mm), making the pattern easy to miss upon a cursory reading of the tracing. A Q wave in III without a Q wave in II sometimes accompanies the pattern, but this is a nonspecific finding that is not included in the diagnostic criteria and requires comparison with previous ECGs.
Mechanism
At the core is acute coronary occlusion, usually in the right coronary artery system, which causes true inferior wall injury but produces only minimal ST elevation in lead III with no elevation in lead II. This ST-T configuration does not meet standard STEMI criteria (which require more prominent and widespread elevation), even though coronary occlusion is present. The pattern may also occur without underlying myocardial pathology. LVH, scarring, bundle branch block, and other causes of secondary ST-T changes can mimic or distort the pattern's criteria, so when present, the diagnostic specificity of the finding is lower, requiring comparison with prior ECG and clinical presentation. The essence of the Aslanger pattern is not the background pathology itself, but the characteristic combination of ST(III)↑ without ST(II)↑ and ST depression in V4–V6, which masks acute occlusion under the guise of a less specific picture.
Causes
- Acute occlusion of the right coronary artery (more commonly) or the circumflex artery
- Possible concomitant multivessel coronary artery disease
- Baseline left ventricular hypertrophy with ST-T changes (a potential factor reducing finding specificity)
- Prior myocardial infarction with scar changes (a potential factor reducing finding specificity)
- Intraventricular conduction delays altering baseline ST-T morphology (a potential factor reducing finding specificity)
Differential diagnosis
- Diffuse subendocardial ischemia (multivessel disease, ST elevation in aVR) — ST depression is more widespread and not associated with the characteristic combination of ST(III)↑ without ST(II)↑ and the ST(V1)/ST(V2) ratio
- Typical inferior STEMI — ST elevation is usually present in two or more contiguous inferior leads (II, III, and/or aVF), often with reciprocal depression in aVL
- Pericarditis — diffuse concave ST elevation and positive T wave in most leads, without focal reciprocal changes; exception is ST depression or T inversion in aVR, sometimes also in V1
- Nonspecific ST-T changes in hypertrophy or block — the characteristic relationship specifically between III, II, and V1 is absent
Clinical significance and management
The Aslanger pattern increases the probability of acute coronary occlusion (OMI) that does not meet formal STEMI criteria. When identifying the pattern in a patient with ischemic pain syndrome, the physician must regard the finding as high suspicion for OMI and ensure urgent expert evaluation, repeat ECG recording, and correlation with the clinical picture. In ongoing ischemia, hemodynamic instability, or life-threatening arrhythmias, emergency coronary angiography is indicated regardless of the troponin result — waiting for troponin elevation should not delay reperfusion in the presence of convincing clinical signs of ongoing ischemia. In a stable patient without ongoing ischemia, decisions are made according to standard NSTE-ACS risk criteria, serial high-sensitivity troponins, ECG dynamics, and the clinical picture; the pattern increases suspicion for occlusion and lowers the threshold for urgent expert evaluation, but does not replace general risk stratification or serve as an independent formal indication for an early invasive strategy in all patients.
Common interpretation errors
- Assessment of ST elevation only in II and aVF, without comparison to III — focus specifically on III is easily missed
- Ignoring ST depression in V4–V6 as 'nonspecific', whereas in combination with elevation in III, this is a diagnostically significant pattern
- Interpreting the picture as diffuse ischemia without considering the ST ratio in V1 and V2
- Delaying immediate invasive evaluation during ongoing ischemia or instability while waiting for formal STEMI criteria or troponin elevation; regional primary reperfusion time targets should not become a reason for such a delay
- Overestimating the Q wave in III as a diagnostic sign of the pattern, whereas this is a nonspecific accompanying finding
1. Which feature is most characteristic of the Aslanger pattern?
This combination is the key difference between the Aslanger pattern and typical inferior STEMI and pericarditis.
2. Which condition is the Aslanger pattern most easily confused with upon superficial ECG reading?
ST depression in chest leads mimics the picture of multivessel ischemia, masking focal occlusion with inferior involvement.
3. What management strategy corresponds to identifying the Aslanger pattern in a patient with ischemic pain syndrome?
The pattern increases the probability of true occlusion without formal STEMI: immediate invasive evaluation is needed in instability, whereas risk stratification for NSTE-ACS is required in a stable patient, rather than waiting for classic criteria.
Frequently asked questions
How does the Aslanger pattern differ from a conventional inferior STEMI?
In typical inferior STEMI, ST elevation is usually present in two or more contiguous inferior leads — II, III, and/or aVF. In the Aslanger pattern, elevation is present in III but absent in II, while chest leads V4–V6 show ST depression, which can mimic other pathology.
Is the Aslanger pattern dangerous?
The pattern increases the probability of acute coronary artery occlusion, frequently of the right coronary artery with inferior involvement, but does not prove it in all cases. The diagnosis is confirmed by clinical presentation, ECG dynamics, and coronary angiography. Missing this pattern may delay reperfusion strategy.
Is emergency PCI required for the Aslanger pattern just like for STEMI?
Formally, the pattern does not meet STEMI criteria, but it is an important ECG marker of probable acute coronary occlusion (OMI). In ongoing ischemia or instability, immediate invasive evaluation is necessary without delay for troponin or the appearance of formal STEMI criteria; in a stable patient, management is determined by standard NSTE-ACS risk criteria, ECG dynamics, and biomarkers.
Which coronary artery is typically involved in this pattern?
Occlusion of the right coronary artery, which supplies the inferior wall, is most commonly described, possibly against the background of concomitant lesion of other vessels.
Why is the Aslanger pattern easy to miss?
The amplitude of ST-segment elevation in lead III is minimal, and ST depression in the precordial leads resembles nonspecific diffuse ischemia rather than focal occlusion.
ECG Course
Interpretation from basics to myocardial infarction — learn to read any ECG using a systematic algorithm.
- Video lessons and theory for every topic
- Simulator case studies under every lesson
- Unlimited ECG simulator practice
- Study guide: "All ECGs in 25 minutes"
ECG Strip Simulator
ECG, radiology, histology, pathomorphology, pharmacology — thousands of flashcards with detailed explanations.
- Real ECG strips, not textbook drawings
- Instant answers and explanations
- Streaks and progress tracking in your dashboard
Related terms
More in the section "Ischemia and Myocardial Infarction"
Sources
- Aslanger E. et al. — primary description of the pattern and its association with acute coronary occlusion (STEMI equivalent / OMI)
- Hampton J. The ECG in Practice, current edition
- Surawicz B., Knilans T. Chou's Electrocardiography in Clinical Practice
- ESC Guidelines for the management of acute coronary syndromes, 2023
Educational material for medical students and physicians. Does not replace clinical guidelines and physical examination; the ECG must always be interpreted in conjunction with the clinical picture.