T wave

  • The T wave is the positive deflection after each QRS complex.
  • It represents ventricular repolarisation.

waves of the ecg

Characteristics of the normal T wave

  • Upright in all leads except aVR and V1
  • Amplitude < 5mm in limb leads, < 15mm in precordial leads
  • Duration (see QT interval)

T wave abnormalities

  • Hyperacute T waves
  • Inverted T waves
  • Biphasic T waves
  • ‘Camel Hump’ T waves
  • Flattened T waves

Peaked T waves

Tall, narrow, symmetrically peaked T-waves are characteristically seen in hyperkalaemia.

hyperkalaemia peaked t waves

Peaked T waves due to hyperkalaemia

Hyperacute T waves

Broad, asymmetrically peaked or ‘hyperacute’ T-waves are seen in the early stages of ST-elevation MI (STEMI) and often precede the appearance of ST elevation and Q waves. They are also seen with Prinzmetal angina.

Hyperacute T waves due to anterior STEMI

Hyperacute T waves due to anterior STEMI

Loss of precordial T-wave balance

Loss of precordial T-wave imbalance occurs when the upright T wave is larger than that in V6. This is a type of hyperacute T wave.

  • The normal T wave in V1 is inverted. An upright T wave in V1 is considered abnormal — especially if it is tall (TTV1), and especially if it is new (NTTV1).
  • This finding indicates a high likelihood of coronary artery disease, and when new implies acute ischemia.

Inverted T waves

Inverted T waves are seen in the following conditions:

  • Normal finding in children
  • Persistent juvenile T wave pattern
  • Myocardial ischaemia and infarction
  • Bundle branch block
  • Ventricular hypertrophy (‘strain’ patterns)
  • Pulmonary embolism
  • Hypertrophic cardiomyopathy
  • Raised intracranial pressure

T wave inversion in lead III is a normal variant. New T-wave inversion (compared with prior ECGs) is always abnormal. Pathological T wave inversion is usually symmetrical and deep (>3mm).

Paediatric T waves

Inverted T-waves in the right precordial leads (V1-3) are a normal finding in children, representing the dominance of right ventricular forces.

Normal pattern of T-wave inversions in a 2-year old boy

Persistent Juvenile T-wave Pattern

T-wave inversions in the right precordial leads may persist into adulthood and are most commonly seen in young Afro-Caribbean women. Persistent juvenile T-waves are asymmetric, shallow (<3mm) and usually limited to leads V1-3.

Persistent juvenile T-waves in an adult

Persistent juvenile T-waves in an adult

Myocardial Ischaemia and Infarction

T-wave inversions due to myocardial ischaemia or infarction occur in contiguous leads based on the anatomical location of the area of ischaemia/infarction:

  • Inferior =  II, III, aVF
  • Lateral =  I, aVL, V5-6
  • Anterior =  V2-6

NOTE:

  • Dynamic T-wave inversions are seen with acute myocardial ischaemia.
  • Fixed T-wave inversions are seen following infarction, usually in association with pathological Q waves.
Inferior ischaemia

Inferior T wave inversion due to acute ischaemia

Inferior T wave inversion with Q waves due to prior inferior MI

T wave inversion in the lateral leads due to acute ischaemia

Anterior T wave inversion with Q waves due to recent anterior MI

Bundle Branch Block

Left Bundle Branch Block

Left bundle branch block produces T-wave inversion in the lateral leads I, aVL and V5-6.

Lateral T wave inversion due to LBBB

Right Bundle Branch Block

Right bundle branch block produces T-wave inversion in the right precordial leads V1-3.

T-wave inversion in the right precordial leads due to RBBB

Ventricular Hypertrophy

Left Ventricular Hypertrophy

Left ventricular hypertrophy produces T-wave inversion in the lateral leads I, aVL, V5-6 (left ventricular ‘strain’ pattern), with a similar morphology to that seen in LBBB.

Lateral T wave inversion due to LVH

Right Ventricular Hypertrophy

Right ventricular hypertrophy produces T-wave inversion in the right precordial leads V1-3 (right ventricular ‘strain’ pattern) and also the inferior leads (II, III, aVF).

right ventricular hypertrophy

T wave inversion in the inferior and right precordial leads due to RVH

Pulmonary Embolism

Acute right heart strain (e.g. secondary to massive pulmonary embolism) produces a similar pattern to RVH, with T-wave inversions in the right precordial (V1-3) and inferior (II, III, aVF) leads.

T wave inversion in the inferior and right precordial leads in a patient with bilateral PEs

Massive PE

Deep T wave inversion in V1-3 with RBBB in a patient with massive PE

Pulmonary embolism may also produce T-wave inversion in lead III as part of the SI QIII TIII pattern (S wave in lead I, Q wave in lead III, T-wave inversion in lead III).

PE

SI QIII TIII pattern in acute PE

Hypertrophic Cardiomyopathy (HOCM)

HOCM is associated with deep T wave inversions in all the precordial leads.

Hypertrophic cardiomyopathy

T wave inversion in V1-6 due to HOCM

Raised intracranial pressure

Events causing a sudden rise in ICP (e.g. subarachnoid haemorrhage) produce widespread deep T-wave inversions with a bizarre morphology.

Raised ICP

Widespread deep T wave inversion due to SAH

Biphasic T waves

There are two main causes of biphasic T waves:

The two waves go in opposite directions:

  • Ischaemic T waves go up then down
  • Hypokalaemic T waves go down then up

Ischaemia

Biphasic T waves due to ischaemia

Hypokalaemia

Biphasic T waves due to hypokalaemia

Wellens’ Syndrome

Wellens’ syndrome is a pattern of inverted or biphasic T waves in V2-3 (in patients presenting with ischaemic chest pain) that is highly specific for critical stenosis of the left anterior descending artery.

There are two patterns of T-wave abnormality in Wellens’ syndrome:

  • Type 1 Wellens’ T-waves are deeply and symmetrically inverted
  • Type 2 Wellens’ T-waves are biphasic, with the initial deflection positive and the terminal deflection negative

Wellens’ Type 1

Wellens’ Type 2

‘Camel hump’ T waves

This is a term used by the great ECG lecturer and Emergency Physician Amal Mattu to describe T-waves that have a double peak or ‘camel hump’ appearance.

There are two causes for camel hump T waves:

  • Prominent U waves fused to the end of the T wave, as seen in severe hypokalaemia
  • Hidden P waves embedded in the T wave, as seen in sinus tachycardia and various types of heart block

Prominent U waves due to severe hypokalaemia

Hidden P waves in sinus tachycardia

Hidden P waves in marked 1st degree heart block

Hidden P waves in 2nd degree heart block with 2:1 conduction

Flattened T waves

Flattened T waves are a non-specific finding, but may represent ischaemia (if dynamic or in contiguous leads) or electrolyte abnormality, e.g. hypokalaemia (if generalised).

Ischaemia

Dynamic T-wave flattening due to anterior ischaemia (above). T waves return to normal once the ischaemia resolves (below).

Dynamic T wave flattening due to anterior ischaemia

T waves return to normal as ischaemia resolves

Hypokalaemia

Note generalised T-wave flattening with prominent U waves in the anterior leads (V2 and V3).

hypokalaemia ecg

T wave flattening due to hypokalaemia

 

Related Topics

Further Reading

Author Credits

References

  • Surawicz B, Knilans TK. Chou’s Electrocardiography in Clinical Practice. 6th Edition. Saunders Elsevier 2008.
  • Wagner, GS. Marriott’s Practical Electrocardiography (11th edition), Lippincott Williams & Wilkins 2007.
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