What constitutes a significant T wave inversion?

Significant T-Wave Inversion: Clinical Interpretation and Evaluation

T-wave inversion is considered significant when it is present in two or more contiguous leads, especially when deep (>0.5 mV), symmetrical, and occurring in leads with predominant R-waves in the appropriate clinical context. 1, 2

Significance by Location

Lateral and Inferolateral T-Wave Inversion

• Most concerning pattern - high specificity for myocardial ischemia/injury
• T-wave inversion in leads I, aVL, V5-V6 (lateral) or II, III, aVF, V5-V6 (inferolateral) strongly suggests:
  • Hypertrophic cardiomyopathy (HCM)
  • Dilated cardiomyopathy (DCM)
  • Left ventricular non-compaction (LVNC)
  • Arrhythmogenic right ventricular cardiomyopathy with LV involvement
  • Myocarditis 1

Anterior T-Wave Inversion

• Significance varies by age, race, and extent:
  • Normal in leads V1-V3 in children >1 month
  • Normal in leads V1-V2 in adult women
  • May be normal in black athletes in leads V1-V4
  • Abnormal in adults when extending beyond V2 (especially without J-point elevation) 1, 2
• When pathological, suggests:
  • ARVC
  • DCM
  • Proximal LAD stenosis (when deep and symmetrical in V2-V4 with QT prolongation) 1

Inferior T-Wave Inversion

• T-wave inversion isolated to leads II, III, aVF cannot be attributed to physiological remodeling
• Requires investigation for:
  • HCM
  • DCM
  • LVNC
  • Myocarditis 1, 2

Global T-Wave Inversion

• Inversion in most leads (frontal plane T vector -100° to -170° with precordial T inversion)
• Strong female predominance
• Associated with:
  • Acute myocardial infarction
  • Central nervous system disorders
  • Coronary artery disease 3

Morphological Characteristics

Ischemic T-Wave Inversion

• Narrow and symmetrical
• Usually preceded by an isoelectric ST segment that is bowed upward (concave)
• Followed by a sharp symmetric downstroke
• Often called "coronary T wave" or "coved T wave" 4

Non-Ischemic T-Wave Inversion

• Prominent, deeply inverted, and widely splayed T waves suggest:
  • Juvenile T-wave patterns
  • Left ventricular hypertrophy
  • Acute myocarditis
  • Wolff-Parkinson-White syndrome
  • Acute pulmonary embolism
  • Cerebrovascular accident
  • Bundle branch block
  • Later stages of pericarditis 4

Evaluation Algorithm

1. Compare with previous ECGs if available, particularly in patients with co-existing cardiac pathology 1

2. Assess for associated findings:

   • ST-segment depression (>0.05 mV in two or more leads suggests ischemia)
   • Q waves
   • QT interval prolongation 1, 2

3. Initial testing:

   • Echocardiography (minimum evaluation) to investigate for underlying cardiomyopathy
   • Cardiac troponin levels 1, 2

4. Additional testing based on location and clinical context:

   • For lateral/inferolateral T-wave inversion:

     • Cardiac MRI (superior to echo for detecting apical HCM, lateral wall LVH, ARVC with LV involvement, and myocarditis)
     • Exercise ECG test
     • 24-hour ECG monitoring
     • Consider family evaluation and genetic screening 1

   • For anterior T-wave inversion:

     • Cardiac MRI
     • Exercise ECG test
     • 24-hour ECG monitoring
     • Signal-averaged ECG (SAECG) if ARVC suspected 1

   • For deep symmetrical T-wave inversion in V2-V4 with QT prolongation:

     • Evaluate for severe proximal LAD stenosis
     • Consider intracranial hemorrhage in appropriate clinical context 1

Special Considerations

Reperfusion

• T-wave inversion in leads with ST elevation may indicate spontaneous reperfusion in anterior STEMI
• Associated with higher prevalence of patent infarct-related artery before intervention 5

Physiological vs. Pathological

• Respiratory variation in T-wave morphology may suggest non-cardiac cause of chest pain
• T-waves becoming positive during held inspiration may indicate a physiological phenomenon 6

Cardiac Memory

• T-wave inversion that persists after resolution of abnormal ventricular activation (e.g., after pacing, arrhythmias)
• Can mimic ischemic changes but typically attenuates over time 7

Pitfalls to Avoid

1. Overlooking normal variants:

   • Juvenile pattern in children and adolescents
   • Race-specific patterns (especially in black athletes)
   • Gender differences (more common in females) 1, 2, 3

2. Misinterpreting non-ischemic causes:

   • Drug effects (e.g., digoxin, tricyclic antidepressants, phenothiazines)
   • Electrolyte abnormalities
   • Post-tachycardia (cardiac memory) 2, 7

3. Failing to recognize high-risk patterns:

   • Deep symmetrical anterior T-wave inversion with QT prolongation (Wellens' syndrome)
   • Global T-wave inversion
   • New T-wave inversion in a patient with chest pain 1, 3