Treatment Of Heart Disease - Electrical Treatment And Pacemakers

Electrical treatment and pacemakers

Electrical treatment, also called cardioversion, may be required to terminate some forms of tachycardia (rapid. beating). This is particularly true for ventricular tachycardia which may be life-threatening and where drugs may ineffective, and for ventricular fibrillation which is a form of cardiac arrest which can be very effectively treated in this way. If the patient is conscious, an anaesthetic must be administered, and then a direct-current electric shock is applied to the chest with two large electrodes. This completely stops the heart's electrical activity and then a normal heart rhythm starts.

Very slow heart rhythms may be treated by artificial pacemakers — on a temporary basis for temporary. problems (usually after heart attacks) or permanently when the condition is long-term. In both cases, an electrical impulse is carried from the pacemaker through a long, narrow tube called a catheter which contains an electrode. The catheter passes, via a vein in the neck or shoulder, into the heart through the superior vena cave and right atrium and across the tricuspid valve, with the tip of the catheter positioned in the right ventricle. The other end is then attached to an artificial pacemaker outside the body for temporary pacing, or miniaturized and implanted beneath the skin for permanent pacing. This implantation is fairly simple and can usually be carried out using only local anaesthetic. In some cases, the pacemaker impulse is transmitted via wires which enter the body through an incision in the chest or below the rib cage, and are then attached to the outside of the heart; the pacemaker itself is then buried in the upper abdomen. These devices are made of or covered by inert materials which will not cause the body to react.

The pacemaker itself consists of an energy source usually made out of lithium batteries, and miniaturized electronic circuitry which generates electrical impulses with a frequency of approximately 70 beats per minute. Modern pacemakers are not usually more than four-or five centimetres in diameter and approximately one centimetre thick, so they can be buried beneath the skin with minimal discomfort.

Pacemakers for implantation are designed to allow a normal life, free from the worry of dizzy spells or blackouts, and, once the wound has healed, to allow normal physical activities such as car driving and sports. The slight bulge of the pacemaker beneath the skin is quickly accommodated and not noticed.