Blast of radiation that can help fix a dodgy heartbeat
RADIOTHERAPY, normally used to treat cancer, is now being used to slow racing hearts. Ray Brown, 70, a retired wood turner, was the first in Britain to have the treatment, as he tells CAROL DAVIS. THE PATIENT
ABOUT 12 years ago my heart would start racing for no apparent reason — suddenly I’d have a fluttering sensation. It was happening two or three times a week, so my GP referred me to hospital, where I was diagnosed with atrial fibrillation, an irregular heartbeat caused by a problem with the electrical signals in my heart.
It can cause blood to pool in your heart, forming clots that could trigger a stroke, so I was given blood-thinners, plus beta-blockers to make my heart work more efficiently.
The doctors also found I had a second, even riskier, heart rhythm disorder — ventricular tachycardia — where at times the heart beats faster than normal. Mine was racing at 230 beats a minute instead of a more usual 60 to 80, probably because of damage done by heart attacks I’d had 20 years earlier.
Ventricular tachycardia can cause your heart to stop — a terrifying thought, especially after another test detected a third problem: blocked coronary arteries were restricting the flow of blood to my heart.
I had a triple heart bypass in August 2008 and a month after that, they implanted a defibrillator to shock my heart back into the right rhythm when needed.
But while the other two conditions stabilised, the ventricular tachycardia got worse.
I had several bad episodes over the next few years when the defibrillator delivered a powerful shock to reset my heart. It felt like being tasered in the chest.
If that wasn’t bad enough, licensing rules stopped me driving for six months every time it went off. My wife, Mary, can’t drive, so we had to put all plans on hold.
By 2015 I’d had two ablations, where they try to burn away the area triggering the abnormal rhythm using a heated electrode on a long wire. But my heart still kept racing, making me very tired and short of breath.
Last October, my cardiologist told me about a new treatment to burn out the faulty area with beams of radiation that can reach areas of the heart the ablation can’t.
I would be one of the first in England to have it, which didn’t worry me — they were running out of options.
I had the treatment in December. I lay on the couch in the radiotherapy machine while the radiographer positioned me to ensure the beams from the machine were directed at the right part of my heart.
The actual treatment took just five minutes and I didn’t even have to stay in hospital overnight. I was warned it would take a few months for the treatment to work and I had minor episodes for six weeks but since then I haven’t had any problems.
THE SPECIALIST
DR EWEN SHEPHERD is a consultant cardiologist.
VENTRICULAR tachycardia is where scars in the patient’s heart, often caused by heart attacks or disease, lead to a short-circuit in the normal electrical signals, causing faulty messages. As a result, the ventricles, or lower pumping chambers of the heart, beat rapidly and cannot pump blood properly around the body. In some cases, it causes the heart to stop and sudden death.
Normally we fit a defibrillator to shock the heart out of this abnormal rhythm when necessary — more than 6,000 patients each year in the UK have one fitted.
We can also try ablation, burning out the rogue area that is sending the faulty messages. This has a success rate of more than 90 per cent in simple forms of tachycardia affecting just the upper heart chambers but only works in 50 per cent of ventricular tachycardia cases because the key tissue is often out of reach, on the outside of the heart or deep inside one of its walls, which we can’t reach with a catheter (a long, thin tube with which ablation is administered).
Stereotactic ablative radiotherapy, or SABR, is a precise form of radiotherapy used to treat lung cancer.
Doctors direct multiple fine beams of radiation from different angles through healthy tissue to converge on the tumour.
This means the tumour gets a high dose of radiation but healthy tissue gets a much lower dose from individual beams, minimising the damage. It can still cause side-effects, including tiredness and nausea.
Now, we have five years of observational studies from the US and Europe showing that it can substantially reduce episodes of ventricular tachycardia, too. Six weeks after treatment, patients have a 90 per cent reduction in the shocks from their defibrillator. This is an excellent result.
We don’t fully understand how it works but it may be changing the cells in the tissue in a way that reduces the chances of them triggering a rapid heartbeat.
Before the procedure, we scan the patient’s scar tissue to pinpoint where the tachycardia is coming from. A team of 15 cardiologists, radiologists, physicists and oncologists then spends three weeks analysing the information to create an accurate map of the patient’s heart.
The procedure takes about an hour — positioning the patient in the radiotherapy machine and lining them up for the beams — although the treatment itself takes just five minutes.
The dose is about a third of the amount a lung cancer patient would receive during a whole course of radiotherapy. With cancer a big dose is needed to try to kill every cell but a lower amount is sufficient for heart tissue.
It is completely painless and there are no wires or incisions.
The patient can then go home, although we give them drugs to treat nausea and fatigue, as radiotherapy tends to always make patients feel tired and sick for a few days.
Over the next six weeks, patients have fewer attacks and the episodes they do have are shorter. In some people, the condition clears up altogether.
We are not sure why the improvement occurs gradually but think it takes time to change the cells, which are all at different stages in their life cycle.
It is probably not suitable for young people or those who respond to catheter ablation because we don’t know the long-term effects. But it is suitable for ventricular tachycardia patients who have no other options.
First used in England for ventricular tachycardia in the summer of 2019, SABR is now used in a number of different hospitals.
The equipment is the same as that used for cancer, so all hospitals with SABR, including those in Ireland could in theory use it for hearts with the right training.