Back to Cardiovascular Diseases
In a cardiac arrest normal circulation of the blood stops due to failure
of the ventricles of the heart to contract effectively during systole.
The resulting lack of blood supply results in cell death from oxygen
starvation. Cerebral hypoxia, or lack of oxygen supply to the brain,
causes victims to immediately loose consciousness and stop breathing.
Cardiac arrest is a medical emergency that, untreated, leads to death
Cardiac arrest directly results from a variety of arrhythmias which
include asystole (known colloquially as a flatline), ventricular fibrillation, ventricular tachycardia, severe bradycardia
and complete heart block with a slow ventricular escape rate.
These arrhythmias can result from:
1. Ischemic heart disease:
In apparently healthy adults, cardiac arrest is often caused by
ventricular fibrillation during myocardial
2. Non-ischemic cardiomyopathy: Dilated and hypertrophic cardiomyopathy.
3. Congenital heart diseases
4. Valvular heart disease: Aortic stenosis.
5. Long QT syndrome: Congenital or acquired.
6. Brugada syndrome
7. Primary ventricular fibrillation
The state of cardiac arrest is diagnosed in an unconscious (unresponsive
to vigorous stimulation) person who does not have a pulse.
An ECG clarifies the exact diagnosis and guides treatmen, but treatment
should begin without awaiting an ECG. The ECG may reveal:
- ventricular fibrillation,
- ventricular tachycardia
- severe bradycardia,
- complete heart block with a slow ventricular escape rate
- or even normal electrical activity (pulseless electrical activity,
formerly called electromechanical dissociation).
Potentially treatable causes of pulseless electrical activity include:
- cardiac tamponade
- tension pneumothorax
- toxins or drug overdoses
- lack of oxygen (hypoxia)
- potassium disturbance (hypokalemia or hyperkalemia)
- decreased blood volume (hypovolemia) due to haemorrhage or dehydration
1. Cardiopulmonary resuscitation (CPR)
Seconds count. Call for help immediately or send someone for help. Begin
cardiopulmonary resuscitation (CPR) immediately. CPR only buys time for
advanced responders to arrive and does not restart the heart. If an
automated external defibrillator (AED) is available, apply it to the
patient ??at once?? and follow the instructions on the device.
2. Code blue
In many hospitals, cardiac arrest results in one of the healthcare
announcing a "Code Blue" for immediate response by an appropriately
trained team of nurses and physicians. The resuscitating team continues
advanced cardiac life support until the patient recovers or a doctor
declares the patient?s death.
2. Advanced Cardiac Life Support (ACLS)
As soon as appropriately trained personnel arrive they apply advanced
cardiac life support protocols ? unless there is a valid do not
resuscitate (DNR) order or a valid advance health directive in accord
with local protocols. If so it is ethically appropriate to permit
natural death to occur in accordance with the wishes of the patient.
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