Pacemaker of the future comes to Mediclinic Panorama

Posted on 19 June 2018

A new, advanced pacemaker procedure is now available at Mediclinic Panorama.

An extremely slow heart rate in older people is often due to heart block. In a patient with heart block, conduction of electrical impulses to the ventricles (pumping chambers) is blocked, sometimes due to damage to heart tissue during a heart attack. This leads to asynchronised and impaired contraction of the ventricles.

Now, a new pacemaker implantation method, known as His bundle pacing (HBP), is set to overtake traditional pacing techniques. ‘I regard His bundle pacing as the pacemaker procedure of the future because it is the first technique that involves direct stimulation of the heart’s own conduction tissue,’ says Dr Razeen Gopal, a cardiac electrophysiologist at the Cape Town Atrial Fibrillation (AF) Centre in Mediclinic Panorama. ‘This leads to synchronised, strong contractions of both ventricles and thus better heart function.’

How does electrical conduction work in a normal heart?

In a normal heart, electrical signals are conducted from the sinoatrial (SA) node in the right atrium, to and through the atrioventricular (AV) node, they then move downwards along the septum to the apex of the heart, and along the right and left ventricles.

How does the new procedure work?

The His bundle transmits electrical impulses from the AV node, down along the septum between the two ventricles and then along the walls of the ventricles. With His bundle pacing, the electrode stimulates the conductive tissue directly, leading to normal, synchronous contraction by both ventricles. The His bundle is located in the septum between the right and left chambers and conducts electrical impulses from the upper chambers to the lower chambers.

The His bundle contains several strings of fibres and divides into two or three (not the same in all people) branches running down the septum and then at the apex of the heart, along the inner walls of the ventricles. These fibres can be described as the ‘electrical highway’: it contains special conductive cells with the ability to conduct electrical signals at an extremely fast pace, allowing the electrical impulses to reach the two ventricles immediately and simultaneously and thus leading to synchronous contractions. Simultaneous, synchronous contractions are essential to achieving maximum output of blood from the ventricles to the body and the brain.

Why is it superior to traditional pacing?

With traditional pacing, the electrode is placed in the right ventricle. The electrical impulses originating from the electrode are not conducted through the electrical highway but are moving at a slower pace through ordinary heart muscle cells. Since the left ventricle is further away from the electrode, the electrical impulses reach the left ventricle later than the right ventricle, leading to delayed contractions by the left ventricle. In the long term, dyssynchrony contractions by the two ventricles will put extra strain on the heart. Even delays of milliseconds between contractions by the two ventricles can impact on heart function.

What does this mean for the future?

‘His bundle pacing is the first physiologically-correct pacing method,’ says Dr Zachary Whinnett, a cardiac electrophysiologist at the National Heart and Lung Institute, Imperial College NHS Trust and the Hammersmith and St Mary’s Hospitals in London says. He assisted Dr Gopal as Proctor (specialist trainer) in the first Cape Town series. Although cardiologists and electrophysiologists are still awaiting data from double-blind clinical trials, Dr Whinnett, who has performed more than 150 of these procedures with his London team, believes His bundle pacing will soon be the new gold standard and preferred method of pacing.

For more information, contact the Cape Town AF Center at

www.capetownafcentre.co.za

Published in Innovation