SET YOUR PACE WITH PACEMAKERS

The idea of having a pacemaker to control your heart may at first appear daunting. The good news is that living with a pacemaker is not a difficult thing so long as one can get back to one’s usual life.

What is a heart block and when is a pacemaker necessary?

Electrical stimulus is necessary for the heart to beat. Electrical circuit located in the heart muscles ensures regular and synchronous contraction of the chambers of the heart. Heart block results when there is a failure of initiation or conduction of electrical impulse through the heart resulting in slowing of the heart beat. The slowing of the heart rate may cause breathlessness, dizziness and even blackout.

Pacemaker is necessary when heart block is causing symptoms or has the potential to cause death.

What are the causes of heart block?

Premature ageing of the electrical circuit is one of the many causes of heart block. Heart block may also be associated with heart attack or diseases of heart muscles and heart valves.

What are the different types of pacemakers and how do they function?

Pacemaker consists of a generator (‘box’) and either one or two wires called ‘leads’. Pacemakers with one lead are called ‘single chamber pacemakers’ and those with two leads are ‘dual chamber pacemakers’. The modern pacemaker generators are smaller than the size of a matchbox. The energy from the batteries is transformed into a series of electrical impulses by the electronic circuit in the pacemaker. These impulses are conducted down the leads to the heart causing the heart to contract and produce a heartbeat.

All the modern pacemakers are of the ‘on demand’ type. The pacemaker can sense that the heart is beating on its own and refrain from discharging any electrical impulse. Only when it senses a missing beat or too much slowing down of the heartbeat, it starts discharging electrical impulses at a fixed rate. Some pacemakers (rate responsive pacemakers) have the ability to speed up their discharge rate when necessary to meet the demand on the heart, for example during periods of vigorous physical activity. Dual chamber pacemakers offer some advantage over the single ones although all pacemakers should prevent blackouts.

How is a pacemaker implanted?

Permanent pacemakers implantation is done under local anaesthetic. The lead is inserted into a vein at the shoulder and passed into the desired cardiac chamber under X-ray screening and the position is secured. The lead is then connected to the pacemaker box, which is positioned in a small ‘pocket’ between the skin and the chest muscle.

What precautions are necessary?

Once the pacemaker is implanted the patient should be able to return to his normal lifestyle. He is allowed to do most ordinary activities, however certain ‘contact sports’, such as football should be avoided as they could damage the pacemaker. Domestic appliances such as electric shavers, hairdryers and microwave ovens do not cause any problem provided they are properly connected and earthed. It is advisable to hold a mobile phone to the opposite ear. The phone should not be carried in the breast pocket next to the generator.  A pacemaker can cause a false alarm when going through an airport security system. Strong electromagnetic fields as associated with arc welders, TV and RADAR transmitters and certain surgical procedures such as diathermy can interfere with pacemaker function. MRI scans should better be avoided unless the pacemaker is MRI compatible.