THE SNAPSHOT
Thousands of Canadians are saved each year by a device inserted in the body that zaps the heart back on track when it鈥檚 threatened by dangerous rhythms. But the side effect is pain and trauma. A 黄色直播 researcher has determined the most effective way to limit the shocks, prompting a re-evaluation of heart treatment worldwide.
THE CHALLENGE
Inserted in John Kell鈥檚 heart is a device that, at unknown intervals, causes him a tremendous amount of pain. It is also saving his life.
Kell has ventricular tachycardia or VT. Previous damage to his heart makes it prone to race spontaneously, veering chaotically from its regular lub-dub rhythm. It strikes without warning鈥攍ub-dub-dub-lub-lub-lub鈥攙entricles becoming frantic, misfiring, contracting so fast that they barely have time to fill with blood, starving his body of oxygen.
But we know what can stop this. We鈥檝e seen it on television. 鈥淐lear!鈥� 鈥攖he two paddles of the defibrillator come down on the chest and鈥攝ap. The patient rises from a contorted state as if wrenched from a nightmare. Brought back from the brink by a jolt that shocks the heart鈥檚 beat back to its proper cadence.
Example of an implantable cardioverter defibrillator.
Zoom into Kell鈥檚 chest to see a miniature version of this defibrillator embedded just below his collar bone. Wires extend from it through veins into his heart, where they monitor its electrical activity. When it goes off track 鈥� zap 鈥� a shock is delivered directly to the heart muscle. Lifesaving but excruciating.
鈥淒id you ever touch a lawn mower sparkplug? You should do it and then you鈥檒l know what the shock is like,鈥� says the 76-year-old Nova Scotia farmer, who recounted the last jolt he got after cutting his daughter鈥檚 lawn. 鈥淵ou might get a little twinge beforehand, but when it hits, it hits. You damn well notice it.鈥�
John Kell. (Submitted image)
Implantable cardioverter defibrillators like Kell鈥檚 became a regular medical procedure in the early 2000s, a hugely consequential solution for people with VT who can experience cardiac arrest at any moment. But with it came a new problem 鈥� patients living in fear of the next shock and the pain that comes with it.
THE SOLUTION
鈥淰entricular tachycardia is the most common cause of sudden death. I would venture to say you and anyone you talk to knows, within one degree of separation, somebody who died suddenly from the condition,鈥� says , a 黄色直播 cardiology researcher and cardiologist with Nova Scotia Health. 鈥淚t鈥檚 great that internal defibrillators can shock us back, but getting a lot of shocks can be quite nasty and can for some be very traumatic.鈥�
Dr. John Sapp in the room where he performs catheter ablations at the听Queen Elizabeth II Health Sciences Centre. (Daniel Abriel photo)
Aside from the ongoing apprehension that a jolt is coming at any second, Dr. Sapp says the shocks are a strong indicator that things are not going well with the heart overall. 鈥淪o, there's a real impetus for us to prevent recurrent arrhythmias and the shocks that come with them.鈥�
Seeking a solution, Dr. Sapp has worked for years with colleagues at Nova Scotia Health and around the world to study the relative success of the two leading treatments 鈥� drugs and the minimally invasive procedure catheter ablation. Using wires like those of the internal defibrillator, catheter ablation allows doctors to discover and cauterize the short circuits that cause the heart to misfire.
Catheter that is snaked through a leg vein into the heart.
鈥淗istorically, the practice has been to try medications first, and if medications weren't working, try still more medications,鈥� says Dr. Sapp, noting that this remained the case even after his 2016 study that demonstrated catheter ablation provides a safer option than stronger drugs.
But now a global rethink is underway, sparked by Dr. Sapp鈥檚 most recent study of the treatments. Published in the November 2024 , Dr. Sapp鈥檚 findings demonstrate for the first time that catheter ablation outperforms medication as the first-line VT treatment.
THE WORK
Dr. Sapp鈥檚 study tracked 416 VT patients implanted with defibrillators after surviving a heart attack. Enrolled in 22 health centers, including Nova Scotia Health鈥檚 QEII Health Sciences Centre, patients were randomly assigned to either drug therapy 鈥� amiodarone or sotalol 鈥� or catheter ablation. The question: which approach reduced VT incidents and posed less risk?
Dr. Sapp, left, preps for the procedure.
For at least two years, researchers tracked participants鈥� erratic heartbeats, electric jolts, and emergency visits. A pattern emerged 鈥� patients who underwent ablation were 25 per cent less likely to die, experience VT-related shocks, end up in emergency, or suffer clusters of arrhythmias called VT storms.
While often effective, Dr. Sapp says VT drugs come with side effects. The leading drug can damage organs over time; the next in line can paradoxically increase the odds of life-threatening arrhythmias. Finding the right dose can be difficult and take time. These risks, impacts, and delays are what Dr. Sapp says set medication behind ablation as the preferred treatment.
THE IMPACT
鈥淭his could be a landmark trial that could have an important impact in how people are cared for around the world,鈥� says Dr. Sapp. 鈥淲e hope the implications influence guidelines from the American Heart Association, the North America-based Heart Rhythm Society, the European Heart Rhythm Association, and European Society of Cardiology.鈥�
Back in Antigonish, Kell hasn鈥檛 experienced any shocks since the procedure was performed in 2019 as part of Dr. Sapp鈥檚 study.听
Shown right: John Kell on the farm with his granddaughters
鈥淚t鈥檚 good mentally to know it鈥檚 not going to happen,鈥� says Kell, who has retired from farming but still appreciates the ability to walk and oversee his land. 鈥淚 don鈥檛 notice any difference now. It鈥檚 there and it鈥檚 working. That鈥檚 all I want.鈥�
On the afternoon of this interview, Dr. Sapp was set to provide a webinar to an audience of 2,000 heart rhythm specialists worldwide, following a series of events with cardiologists, all keen to learn about his findings.
鈥淚t's been a bit of a whirlwind. But that's why we did this. To definitively answer the scientific question: what should I do for my patients?鈥�