A story of a pacemaker

A pacemaker is a tiny device that is implanted inside a human's body to treat patients with disturbances in their hearts' electrical function.

The first pace maker ever implanted was 70 years ago, and from that time till now, this field has witnessed huge technological advances and capabilities enabling it to treat a wide array of electrical disturbances.

The heart is a muscle that contracts to eject sufficient blood to satisfy the body needs.

Prior to each contraction, an electrical impulse, generated by a highly specialized cellular apparatus called the sinoatrial node, drives each heart beat. 

Therefore, when this inherent mechanism fails to drive the heart, the pace maker serves as a substitute for the former.

This device has been empowered by more advanced computers that serve to abolish any asynchrony that may exist between the native electrical impulses and the device's. For an example, the pacemaker is urged to elevate its firing rate, and hence the heart beats, at times of exercise. Moreover, if it senses that the native electrical activity is sufficient to drive the heart, it turns off saving power and battery life.

A huge part of its innovation lies in finding a delicate way in connecting the pace maker with heart. That is done through electrical wires originating from the device and traversing blood vessels to finally reside in the heart's chambers.

The virtual battery life may extend up to 10 years, and that of the electrical wires may extend up to 20 years, in contrast to the older versions where battery and wire replacement were carried on yearly! 

Add to that, the size of the pacemaker has undergone several refinements to decrease it, and the current pacemaker now measures approximately the size of a lighter!

Being the great invention it is, it is not immune to complications. For an example the device may dislocate from its implanted site to elsewhere in the body.

Add to that, the caring physician may recommend at times to remove the device, which may not be an easy procedure.

And finally, its cost is expensive but hopefully with time, it can be affordable by many.

Another electrical disturbance that may inflict the heart and can prove fatal is ventricular fibrillation.

It has been the culprit for the majority of sudden cardiac death cases.

The only way to stop the abnormal electrical activity inflicting the heart, that is ventricular fibrillation, is to deliver an electrical shock that may reach up to hundreds of volts andrevert to the normal electrical activity.

To be effective, it should delivered promptly, otherwise, and secondary to hypo perfusion of vital organs, the patient may suffer from permanent damage and disability

Bearing this in mind, many of the developed countries are providing defibrillator devices available for the lay public when such an event occurs.

 Nowadays, it has been feasible to supply pace makers with more sophisticated technologies and advanced computerized batteries to detect ventricular fibrillation and deliver the electrical shock needed to revert it.

Such technology is preserved for individuals with the highest of risk such as those with heart failure or those who sustained a previous episode of ventricular fibrillation.

Part of the complications that can be anticipated from device implantation are bleeding at the site of implantation, perforation of a heart chamber during electrical wire deployment or bacterial infections.

To avoid such tragedy, new devices are capable of tracking the heart rhythm and delivering the adequate electrical shock without the need for wires. However, its cost is much more that the former.

Lastly but not the least, part of the technology is also aimed at treating heart conditions in which the heart walls are not moving in synchrony.

The heart muscle consists of cardiomyocytes which all together work as a single unit.

In a limited population of individuals with severe heart failure, such asynchrony can be managed by implanting electrical wires that deliver the appropriate electrical impulses to help contract the heart as a single unit.

However it is only recommended to a special population of individuals based on electrocardiographic and echocardiography criteria. 

In this small talk, the pace maker, CRTD and ICD has been explained briefly for the audience.

For more help, please ask for expert opinion.

An electro physiologist is a physician whose interest is in diagnoses and treatment of electrical disturbances of the heart.

 

Dr. Mounir Alzakah Electrical Cardiac Consultant Specialty Hospital