<unk>  <unk>  refers to cardiac arrest in which the electrocardiogram shows a heart rhythm that should produce a pulse, but does not.<unk>  is found initially in about 55% of people in cardiac arrest. Under normal circumstances,<unk>  activation of muscle cells precedes mechanical contraction of the heart (known as electromechanical coupling). In<unk> , there is<unk><unk>  but insufficient cardiac output to generate a pulse and supply blood to the organs, whether the heart itself is failing to contract or otherwise. While<unk>  is classified as a form of cardiac arrest, significant cardiac output may still be present which may be determined and best visualized by bedside ultrasound. Cardiopulmonary resuscitation (CPR) is the first treatment for<unk> , while potential underlying causes are identified and treated. The medication epinephrine (aka adrenaline) may be administered. Survival is about 20%.
Pulseless electrical activity
Electrical alternans
Ventricular escape beat
Hyperdynamic precordium
High frequency QRS
Infradian rhythm
Junctional escape beat
Pulsus alternans