Left Ventricular Assist Device

Ventricular assist device
Intervention
A left ventricular assist device (LVAD) pumping blood from the left ventricle to the aorta, connected to an externally worn control unit and battery pack.
MedlinePlus	007268
[]

A ventricular assist device (VAD) is an electromechanical device for assisting cardiac circulation, which is used either to partially or to completely replace the function of a failing heart. The function of VADs is different from that of artificial cardiac pacemakers; some are for short-term use, typically for patients recovering from myocardial infarction (heart attack) and for patients recovering from cardiac surgery; some are for long-term use (months to years to perpetuity), typically for patients suffering from advanced congestive heart failure.

VADs are distinct from artificial hearts, which are designed to assume cardiac function, and generally require the removal of the patient's heart. Moreover, VADs are designed to assist either the right ventricle (RVAD) or the left ventricle (LVAD), or to assist both ventricles (BiVAD). The type of ventricular assistance device applied depends upon the type of underlying heart disease, and upon the pulmonary arterial-resistance, which determines the workload of the right ventricle.

The left-ventricle assistance device (LVAD) usually is the most common device applied to a defective heart, but when the pulmonary arterial-resistance is high, then a right-ventricle assistance device (RVAD) might be necessary to resolve the problem of cardiac circulation. Normally, the long-term VAD is used as a bridge to transplantation — keeping alive the patient, with a good quality of life — while awaiting a heart transplant; however, an LVAD sometimes is applied as destination therapy, that is, the patient shall not undergo a heart transplantion; and an LVAD sometimes is applied as a bridge to recovery.

The pumps used in VADs can be divided into two main categories – pulsatile pumps, that mimic the natural pulsing action of the heart, and continuous flow pumps. Pulsatile VADs use positive displacement pumps. In some of these pumps, the volume occupied by blood varies during the pumping cycle, and if the pump is contained inside the body then a vent tube to the outside air is required.