T wave

T wave Overview

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

ECG basics: waves, segments and intervals LITFL ECG library

Characteristics of the normal T wave

  • Upright in all leads except aVR and V1
  • Amplitude < 5mm in limb leads, < 10mm in precordial leads (10mm in men, 8mm in women)
  • Duration (see QT interval)

T wave abnormalities

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

Peaked T waves

ECG Peaked T waves hyperkalemia
Tall, narrow, symmetrically peaked T-waves are characteristically seen in 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
Prinzmetal angina.
Loss of precordial T-wave balance

Loss of precordial T-wave balance 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

Paediatric T waves Normal T waves 2 year old boy
Inverted T-waves in the right precordial leads (V1-3) are a normal finding in children, representing the dominance of right ventricular forces.

Persistent Juvenile T-wave Pattern

Juvenile-T-wave-inversion 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.

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 T wave inversion due to acute ischaemia
Inferior T wave inversion due to acute ischaemia

Inferior T wave inversion with Q waves
Inferior T wave inversion with Q waves – prior myocardial infarction

Lateral; leads T wave inversion acute ischaemia
T wave inversion in the lateral leads due to acute ischaemia

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

Bundle Branch Block

Left Bundle Branch Block

Left bundle branch block with T-wave inversion

Right Bundle Branch Block

Right bundle branch block with T-wave inversion

Ventricular Hypertrophy

Left Ventricular Hypertrophy

Left ventricular hypertrophy with T-wave inversion
  • Left ventricular hypertrophy (LVH) 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.

Right Ventricular Hypertrophy

Right ventricular hypertrophy with T-wave inversion
  • 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).

Pulmonary Embolism

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

Acute massive PE with s! Q3 T3 RBBB TWI V1-3
Acute massive PE with SI QIII TIII RBBB TWI V1-3

SI QIII TIII

  • 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
SI QIII TIII pattern in acute PE
Acute massive PE with SQIII TIII RBBB TWI V1-3

Hypertrophic Cardiomyopathy (HCM)

Hypertrophic Cardiomyopathy (HCM)

Raised intracranial pressure (ICP)

ECG TWI Raised intracranial pressure (ICP) SAH
  • Events causing a sudden rise in intracranial pressure (e.g. subarachnoid haemorrhage) produce widespread deep T-wave inversions with a bizarre morphology.

Biphasic T waves

There are two main causes of biphasic T waves:

The two waves go in opposite directions:

Biphasic T waves due to ischaemia – T waves go UP then DOWN

Biphasic T waves due to ischaemia

Biphasic T waves due to Hypokalaemia – T waves go DOWN then UP

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/following ischaemic sounding 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 A = Biphasic T waves with the initial deflection positive and the terminal deflection negative (25% of cases)
  • Type B = T-waves are deeply and symmetrically inverted (75% of cases)

Note: The T waves evolve over time from a Type A to a Type B pattern

Wellens Type A
Wellens Type B

‘Camel hump’ T waves

Camel hump’ T waves is a term used by Amal Mattu to describe T-waves that have a double peak. 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
Prominent U waves due to severe hypokalaemia

Hidden P waves in sinus tachycardia
Hidden P waves in sinus tachycardia

Hidden P waves in marked 1st degree heart block
Hidden P waves in marked 1st degree heart block

Hidden P waves in 2nd degree
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
Dynamic T wave flattening due to anterior ischaemia

T waves return to normal as ischaemia resolves
T waves return to normal as ischaemia resolves

Hypokalaemia

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

T-wave flattening in hypokalaemia


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Emergency Physician in Prehospital and Retrieval Medicine in Sydney, Australia. He has a passion for ECG interpretation and medical education | ECG Library |

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