Difference Between Artificial Heart & Vads

The difference between a VAD and an artificial heart is that the entire human heart is not explanted with a ventricular assist device (VAD) as it is with implantation of a completely artificial heart. VADs are indicated for a number of reasons, but in any account the devices are used in an assistive capacity to an ailing heart that has suffered injury, as in a heart attack, or is progressively weakening due to disease processes.

Lower Heart Anatomy

• The ventricles are located in the smalled cone-like bottom of the heart.

  Located at the bottom of the human heart are the right and left ventricles. The ventricles are the more muscular areas of the heart because each acts as a pump. The left side of the heart is the "high pressure" side, so that specific ventricle is more muscular than the other. When the heart functions normally except for the vigor of force to expel oxygen-rich blood back through the body, a VAD may be indicated.

Device Appearance

• In this x-ray, the heart appears on the right side of the spine in the chest cavity.

  The ventricular assist device is not indwelling. Rather, the bulk of the device remains on the outside of the body. A VAD can be applied to either left or right ventricle, and, under certain circumstances, can be used to assist both sides simultaneously. The VAD is grafted to a ventricle via a long tube protruding from the chest. A second tube exiting the VAD circumvents the heart valve and is grafted to the upper atrium.

Mechanism of Function

• Ventricular assist devices help to release the workload on a weakening heart.

  A pump in the VAD is always active, powered by large rechargeable batteries. Because a certain amount of force is necessary for blood to move through a heart valve from lower to upper chamber, the device assists the ailing ventricle by transporting blood around it, thus relieving cardiac workload. VADs can be used as a kind of bridge device until a healthy human heart is procured, or it can be worn for years.

Comparing VADS with Artificial Hearts

• VADS assist in cardiac management while artificial hearts do all the cardiac workload.

  In a complete heart transplant, the ailing organ is removed while the patient is placed on artificial bypass in the operating room. The artificial heart is grafted to the great vessels in the mediastinum. The mechanical heart is then powered on, and the patient taken off operative bypass. While as a ventricular assist device acts as a compliment to normal heart function, a complete artificial heart device does every aspect of the failing removed organ.

Maintaining a VAD

• Rechargable battery sets become a necessity for VAD patients.

  A person with a VAD must make certain he carries several sets of batteries to supply the pump motor. The batteries are worn in shoulder harnesses resembling side arm holsters. The device pump can be "pulsitile" or "continuous" in flow. Pulsitile pumps try to imitate the pulse pattern of a healthy heart. In a continuous flow VAD, the heart rhythm is not emulated. Anti-coagulant drugs are used to prevent blood from clotting inside the device.

Prognosis

• Antibiotics and immunosuppressants help to fight VAD-related infections.

  The first VAD was placed in 1984. As medical technology trials become more sophisticated, ventricular assist devices continue to undergo refinements. Implantable device prototypes show great promise. Although bacterial, viral and fungal infections are all threats to patients with external VAD modules, proper use of antibiotics and immunosuppressants have increased wearer longevity by delaying the need for a complete heart transplant with a human donor heart by close to a decade or more.