Faulty electric signals in the heart that raise the risk of life-threatening strokes can be homed in on for the first time — thanks to a crystal bauble-tipped wand.
The AcQMap could revolutionise treatment for the millions of people with atrial fibrillation, which is when the heart beats erratically — particularly where all other treatments have failed. The device uses sound waves to detect precisely where faulty heartbeats are occurring, allowing treatment to be tailored to an individual patient’s needs.
Normally, doctors can’t pinpoint the problem and so treat the most commonly affected areas of the heart using ablation, burning away tissue through heat or freezing. However, if this doesn’t work, it can weaken the heart rather than heal it.
Atrial fibrillation develops when electrical impulses in the heart are fired chaotically by tissue in the organ’s upper chambers, the right and left atrium, overriding the heart’s natural pacemaker. Symptoms include dizziness, shortness of breath and tiredness.
It tends to affect those over 65, those with high blood pressure or diabetes or those who are overweight. Caffeine or alcohol can also be triggers.
When the heart beats normally, its muscular walls tighten to push blood around the body. They then relax so the heart can fill with blood again.
In atrial fibrillation, the atria contract randomly and, sometimes, so fast that the heart muscle cannot relax properly between each contraction. This means blood can pool inside the heart and form clots. If one of these clots reaches the brain, it can cause a stroke.
Treatments include blood-thinning drugs and catheter ablation, when a flexible thin tube (catheter) is inserted into a vein at the top of the leg and up into the top chambers of the heart, usually under local anaesthetic.
The tube is threaded into the areas of muscle to blame for most cases of atrial fibrillation. Heat-generating high frequency radio waves are transmitted through one of the tubes, to create scar tissue around the area sending abnormal signals, blocking them.
However, difficulty in finding the faulty tissue means that ablation may only work in two-thirds of procedures. While it is possible to have a second or third ablation, repeated procedures risk further weakening the heart, if healthy tissue is unnecessarily ablated.
But now, with AcQMap, doctors can see the pattern of electrical activity in the heart and zero in on the right area.
It is expected that tailoring the treatment in this way will increase success rates, which will mean fewer repeat procedures. The device consists of a catheter, with a basket at its tip, that expands inside the heart. This is inserted as a catheter would be during a normal ablation.
The basket is studded with ultrasound crystals that emit sound waves to gauge the heart’s shape, creating a 3D image.
It also contains electrodes which sense the heart’s electrical activity and superimpose it on the model, creating a real-time map of the areas behind the atrial fibrillation.
Finally, the device tracks the position of the ablation catheter, allowing it to be steered to the area causing the problem.
AcQMAP is only available in the UK as part of a European clinical trial called the RECOVER-AF study. This involves 100 patients at 15 sites, including the Oxford Heart Centre at Oxford University Hospitals (OUH); The James Cook University Hospital, Middlesbrough; Freeman Hospital in Newcastle; Barts Heart Centre at St Bartholomew’s Hospital, The Royal London Hospital and Royal Brompton Hospital, all in London; Liverpool Heart and Chest Hospital; Royal Papworth Hospital in Cambridge and Glenfield Hospital in Leicester.
Participants will have their heart rate checked three, six and 12 months after initial treatment.
Dr Tim Betts, the study’s chief investigator and a consultant cardiologist at OUH, said: ‘This is an important step forward in offering an effective solution to people with atrial fibrillation.
‘It promises an individualised, focused treatment that should translate into higher success rates, particularly for those with very challenging arrhythmias.’
© Daily Mail