Raised Intracranial Pressure

Electrocardiographic Abnormalities

Raised ICP is associated with certain characteristic ECG changes:

• Widespread giant T-wave inversions (“cerebral T waves”).
• QT prolongation.
• Bradycardia (the Cushing reflex - indicates imminent brainstem herniation).

Other possible ECG changes that may be seen:

• ST segment elevation / depression – this may mimic myocardial ischaemia or pericarditis.
• Increased U wave amplitude.
• Other rhythm disturbances: sinus tachycardia, junctional rhythms, premature ventricular contractions, atrial fibrillation.

In some cases, these ECG abnormalities may be associated with echocardiographic evidence of regional ventricular wall motion abnormality (so-called “neurogenic stunned myocardium”). 

Causes

ECG changes due to raised ICP are most commonly seen with massive intracranial haemorrhage:

• Subarachnoid haemorrhage
• Intraparenchymal haemorrhage (haemorrhagic stroke)

They may also be seen with:

• Massive ischaemic stroke causing cerebral oedema (e.g. MCA occlusion)
• Traumatic brain injury
• Cerebral metastases (rarely)

In one case series, the ECG pattern of cerebral T-waves with prolonged QT interval was seen in 72% of patients with SAH and 57% of patients with intraparenchymal haemorrhage. 

 

ECG Examples

Example 1 – SAH

• Widespread, giant T-wave inversions (“cerebral T waves”) secondary to subarachnoid haemorrhage.
• The QT interval is also grossly prolonged (600 ms).

 

Example 2 – SAH

• Another example of cerebral T-waves with marked QT prolongation secondary to subarachnoid haemorrhage.

 

Example 3 – SAH

• Widespread T-wave inversions with slight ST depression secondary to subarachnoid haemorrhage.
• The QT interval is prolonged (greater than half the R-R interval).
• This ECG pattern could easily be mistaken for myocardial ischaemia as the T-wave morphology is very similar, although obviously the clinical picture would be very different (coma versus chest pain).

 

Example 4 – Traumatic Brain Injury

• This ECG was taken from a previously healthy 18-year old girl with severe traumatic brain injury and massively raised intracranial pressure (30-40 mmHg).
• There is widespread ST elevation with a pericarditis-like morphology and no reciprocal change (except in aVR and V1).
• She had no cardiac injury / abnormality to explain the ST elevation.
• The ST segments normalised as the intracranial pressure came under control (following treatment with thiopentone and hypertonic saline).

 Video

Amal Mattu presents a case of intracranial haemorrhage with characteristic ECG findings.

http://www.youtube.com/watch?v=E27t7nNJAt8&feature=player_embedded

Further Reading

• ECG BASICS – Waves, Intervals, Segments and Clinical Interpretation
• ECG CLINICAL CASES – Your favourite ECG’s placed in clinical context with a challenging Q&A approach
• ECG and Cardiology Eponymous Syndromes – Cheats guide to eponymous emancipation
• ECG Reference Sites on the WEB – the best of the rest

Author Credits

References

• Chan TC, Brady WJ, Harrigan RA, Ornato JP and Rosen PR. ECG in Emergency Medicine and Acute Care. Elsevier 2005
• Mattu A, Brady W. ECGs for the Emergency Physician 2, BMJ Books 2008.
• Surawicz B, Knilans T. Chou’s Electrocardiography in Clinical Practice (6th edition), Saunders 2008.
• Wagner, GS. Marriott’s Practical Electrocardiography (11th edition), Lippincott Williams & Wilkins 2007.