ECG and Left Ventricular Aneurysm

ECG and Left Ventricular Aneurysm

Left ventricular (LV) aneurysm is a late mechanical complication of transmural myocardial infarction, most commonly following an anterior wall STEMI. Recognizing its characteristic ECG pattern is crucial because it can closely mimic acute STEMI and may lead to unnecessary thrombolysis or cath lab activation if misinterpreted.

What Is a Left Ventricular Aneurysm

A left ventricular aneurysm is a thin, scarred, dyskinetic segment of myocardium that bulges outward during systole. It usually develops weeks after a full-thickness myocardial infarction due to replacement of necrotic myocardium with fibrous tissue.

ECG Changes in Left Ventricular Aneurysm

The ECG findings are distinctive and relatively stable over time.

Distribution of ECG Changes

ECG abnormalities are most commonly seen in the precordial leads, especially V1 to V6, reflecting involvement of the anterior wall. Inferior lead involvement (II, III, aVF) is uncommon unless the aneurysm involves the inferior wall.

ST-Segment Elevation

Persistent ST elevation is the hallmark ECG feature.

• ST elevation may be concave or convex

• The elevation is static and does not evolve over time

• ST elevation persists for more than 2 weeks after the index STEMI

• There are no reciprocal ST depressions

This persistence helps differentiate LV aneurysm from acute myocardial infarction, where ST changes evolve dynamically.

Pathological Q Waves

Deep, wide pathological Q waves are typically present in the affected leads. These represent completed transmural infarction and myocardial scar formation.

T-Wave Changes

T waves are usually flat or inverted in the involved leads. Unlike acute ischemia, there is no dynamic T-wave evolution.

Key ECG Features Summary

• Persistent ST elevation (>2 weeks post-MI)

• Static ST segments with no serial change

• Pathological Q waves

• Flat or negative T waves

• Absence of reciprocal ST depression

Differentiating LV Aneurysm from Acute STEMI

This distinction is clinically critical.

Acute STEMI: • Dynamic ECG changes

• Rising and falling ST segments

• Reciprocal ST depression

• Acute chest pain with positive biomarkers

Left Ventricular Aneurysm: • Chronic, stable ECG pattern

• Persistent ST elevation

• No reciprocal changes

• Often asymptomatic or chronic heart failure symptoms

Clinical Importance

Misdiagnosing LV aneurysm as acute STEMI can lead to inappropriate thrombolysis or invasive procedures. Always correlate ECG findings with:

• Clinical history of prior MI

• Duration of symptoms

• Cardiac biomarkers

• Echocardiography (shows dyskinetic or akinetic aneurysmal segment)

Complications of Left Ventricular Aneurysm

• Heart failure

• Ventricular arrhythmias

• Mural thrombus and systemic embolization

• Rarely, ventricular rupture

Take-Home Message

Persistent ST elevation with pathological Q waves and flat or inverted T waves weeks after a myocardial infarction strongly suggests left ventricular aneurysm rather than acute ischemia. Careful ECG interpretation combined with clinical context and echocardiography prevents misdiagnosis and guides appropriate management.

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