These possible causes are remembered as the 6 Hs and the 6 Ts. See Hs and Ts * Hypovolemia * Hypoxia * Hydrogen ions (Acidosis) * Hyperkalemia or Hypokalemia * Hypoglycemia * Hypothermia * Tablets or Toxins * Cardiac Tamponade * Tension pneumothorax * Thrombosis (e.g., myocardial infarction, pulmonary embolism) * Tachycardia * Trauma (e.g., hypovolemia from blood loss) The possible mechanisms by which the above conditions can cause<unk>  in<unk>  are the same as those recognized as producing circulatory shock states. These are (1) impairment of cardiac filling, (2) impaired pumping effectiveness of the heart, (3) circulatory obstruction and (4) pathological vasodilation causing loss of vascular resistance and excess capacitance. More than one mechanism may be involved in any given case.
Pulseless electrical activity
Electrical alternans
Ventricular escape beat
Hyperdynamic precordium
High frequency QRS
Infradian rhythm
Junctional escape beat
Pulsus alternans