Brain Death

  Prompt diagnosis of brain death and the recognition of cardiac activity in this condition are of clinical

      importance, since patients in a state of brain death are considered to be
potential donors for

      organ transplants
.

  Electrocardiography is not among the criteria used for diagnosing brain death.

      However, brain death subjects
frequently show ECG abnormalities.



ECG findings in brain-dead subjects(in order of decreasing frequency)

  J point elevation (J wave)

  J point depression

  QT interval prolongation.

  ST segment depression.

  Negative T waves.

  ST segment elevation.

  Tall T waves.

  PR interval prolongation.




Heart rate variability (HRV)

  Heart rate variability (HRV) is a physiological variation in the time interval between heartbeats.

  It is measured by the variation in the beat-to-beat interval.

 
HRV approaches zero during brain death.



References (click on the links for abstract or free full-text articles)

  Chest 1975;67(4):425-432.

  Am J Physiol 1998;275(4 Pt 2):R1287-1292.

  Pediatr Cardiol 2010;31:1064-1069.

  J Heart Lung Transplant 2001;20(3):350-357.





ECG 1a. The ECG above belongs to a 34 years-old woman with brain tumor.
It was recorded before her brain surgery.
She has no known heart disease and her preoperative ECG is normal.
The RR intervals slightly vary, as in a healthy subject.

Click here for a more detailed ECG




ECG 1b. The ECG above belongs to the same woman.
It was recorded on 5th postoperative day, while she was brain-dead.
Unlike the ECG 1a, the above ECG shows extensive T wave negativity, J point depression, and ST segment depression.
The ST segment depression pattern in the above ECG is not typical for myocardial ischemia.
At first glance, it seems like sagging type ST depression, frequently seen in patients with Digoxin intoxication.
Unlike symmetrically sagging ST depression in Digoxin intoxication, the above ECG shows asymmetrical ST segment depression.
While the above ECG was being recorded, the non-invasive blood pressure monitor was showing 50/27 mmhg.
Another finding in the above ECG is that there is no sinus arrhythmia, there are even no minor changes in the RR intervals.
The patient died 30 hours after recording of the above ECG.

Click here for a more detailed ECG