QS Study

Cardiac Arrest

Definition: Cessation of all spontaneous rhythmical impulses of the heart. It is a sudden loss of blood flow resulting from the failure of the heart to effectively pump. When our heart stops pumping blood, our brain is famished of oxygen. This causes us to fall insensible and stop breathing.

Cardiac arrest occurs during deep anesthesia when pt. develops severe hypoxia because of inadequate respiration. Symptoms include loss of consciousness and abnormal or absent breathing. The hypoxia prevents the muscle fiber and conducting fibers from maintaining normal electrolyte concentration differentials across their membrane and their excitability may be so affected that the automatic rhythmicity disappears. The most common cause of a cardiac arrest is a life-threatening abnormal heart rhythm called ventricular fibrillation (VF). Ventricular fibrillation happens when the electrical activity of your heart becomes so chaotic that the heart stops pumping and quivers or ‘fibrillates’ instead. Electronic cardiac pacemakers have been used to overcome this situation.

Fig: Cardiac arrest

Sudden collapse, no pulse, no breathing, and loss of consciousness are common symptoms of Cardiac Arrest. Some other symptoms include fainting, blackouts, dizziness, chest pain, shortness of breath, weakness etc.

Causes of cardiac arrest:

  • coronary heart disease
  • heart attack
  • cardiomyopathy and some inherited heart conditions
  • congenital heart disease
  • heart valve disease
  • acute myocarditis (inflammation of the heart muscle)