Pulseless ventricular tachycardia is a life-threatening cardiac emergency that ends in death without prompt and immediate treatment. The term tachycardia refers to a rapid heart rate, routinely understood as greater than 100 beats per minute. Ventricular refers to a rapid heart rate electrically initiated by the heart's lower chambers — the ventricles — as opposed to the usual control center in the atria, the Bundle of His. Pulseless refers to the fact that the ventricles are pumping so quickly and out of order with the atria that the usual volume of blood ejected with each heartbeat — a pulse — is absent. Thus, this condition is a temporary state wherein the heart's large ventricles are pumping very rapidly but completely ineffectually.
As noted above, pulseless ventricular tachycardia is a temporary cardiac condition. It is considered temporary because it is inconsistent with life. Despite the fact that the heart is moving, it is not beating and thus, is failing to circulate oxygenated blood to the body tissues and organs, including the heart. Hypoxia or low oxygen concentrations result in cellular and tissue death within minutes. Pulseless ventricular tachycardia devolves into ventricular fibrillation, wherein the heart simply quivers — casually known as "v fib" — which quickly turns to asystole, the straight line traced on an EKG machine known to fans of television medical dramas.
Many medical conditions can predispose someone to the development of pulseless ventricular tachycardia. Previous heart disease with tissue death along the heart's electrical conduction pathways can be a major factor. It is thought by experts that a sustained event of pulseless ventricular tachycardia has often been preceded by short, self-limited runs — six beats or less — on one or more occasions. Other conditions that can facilitate the development of this condition include hypokalemia or hypoxia. Hypokalemia is the medical term for low serum levels of potassium, which tends to make the ventricles irritable; hypoxia, on the other hand, describes a situation of low oxygen and this condition may damage higher levels of cardiac electrical functioning.
Treatment of pulseless ventricular tachycardia is an emergency procedure commonly referred to as a code. Manual chest compressions are administered in order to simulate functional heartbeats and blood volume circulation. Intubation, or the placement of a breathing tube, is performed and oxygen is administered with a manual bag valve mask or ventilator to help avoid tissue death. An electrical shock is administered by an automated electrical defibrillator (AED) or a manual defibrillator in an attempt to interrupt the dangerous ventricular rhythm and allow a functional heart rhythm to resume. If the code has been successful, the patient is treated in an intensive care unit (ICU) or cardiac care unit (CCU).