Are there electrocardiogram (ECG) changes associated with aortic aneurysms?

ECG Changes Associated with Aortic Aneurysms

Aortic aneurysms themselves do not typically cause specific ECG changes, but when present, ECG abnormalities are usually indirect manifestations related to complications, associated cardiac conditions, or mechanical effects of the enlarged aorta. 1

Direct ECG Manifestations of Aortic Aneurysm

The most specific ECG finding directly attributable to aortic aneurysm is low QRS voltage in precordial leads (V1-V3), which occurs when an enlarged ascending aortic aneurysm interposes itself between the heart and chest wall electrodes, acting as an electrical insulator 1. This represents a rare but recognized indirect sign of large aortic aneurysm on ECG 1.

Common ECG Patterns in Aortic Disease

While the aneurysm itself rarely causes ECG changes, the majority of patients with thoracic aortic disease have abnormal ECGs 2, 3:

• Only 27-40% of patients with type A aortic dissection have completely normal ECGs 2, 3
• Acute ECG changes occur in approximately 50% of cases with acute aortic syndromes 3
• Chronic ECG abnormalities are present in 36.5% of cases 3

Specific ECG Abnormalities Encountered

ST-segment and T-wave changes are the most frequent abnormalities 4, 2, 3:

• T-wave inversion occurs in 38.6% of cases 4
• ST depression is seen in 34.0% of cases 3
• Nonspecific ST-T changes occur in 21.4% of cases 3
• ST elevation mimicking acute MI occurs in 8.2-16.3% of cases 4, 3

Left ventricular hypertrophy patterns may be present, particularly when aortic valve disease coexists with ascending aortic aneurysm 5.

Conduction abnormalities can occur 5:

• Bundle branch blocks
• AV conduction delays (first to third degree)
• QRS duration >120 milliseconds (associated with worse long-term prognosis) 4

Critical Clinical Pitfall

The presence of acute ischemic ECG changes does NOT reliably indicate coronary involvement in aortic dissection 4. Among patients with acute aortic dissection who underwent coronary angiography, 70% had normal coronary arteries despite having acute ECG changes 4. Furthermore, acute ECG changes were not associated with increased troponin levels or presence of coronary lesions 4.

This creates a dangerous diagnostic trap: patients with nonspecific ST-T changes experience significant delays in diagnosis (5.8 hours vs 4.5 hours to diagnosis) 2, likely because clinicians pursue a primary cardiac workup rather than considering aortic pathology 2.

Prognostic Significance

Specific ECG patterns carry prognostic implications 4, 2:

• ST elevation in lead aVR predicts higher hospital mortality (OR 5.30) 4
• QRS >120 milliseconds predicts worse long-term mortality (HR 2.45) 4
• Any abnormal ECG finding is associated with higher surgical mortality (20.6% vs 11.9%) 2
• ST depression or T-wave changes correlate with shock (65.2% vs 28.8%) and cardiac tamponade (51.2% vs 15.0%) 3

Practical Approach

When evaluating chest pain with ECG abnormalities, maintain high clinical suspicion for aortic pathology 4, 2, 3. The ECG should never be used to exclude aortic disease, as ECG-gated CT angiography remains the gold standard for diagnosis 6.

ECG-gated imaging is specifically recommended for aortic evaluation to minimize motion artifact and ensure reproducible measurements at the same cardiac phase 6. However, this refers to the imaging technique itself, not to diagnostic ECG findings 6.

Do not delay definitive imaging (CTA or MRA) based on ECG findings alone 6. The sensitivity of clinical tools including ECG for detecting thoracic aortic disease is limited, and a normal ECG does not exclude significant aortic pathology 7.