In cases where heart rate and rhythm medication cannot be tolerated or fail to restore the heart to normal sinus rhythm, a number of medical procedures and interventions carried out in hospital are available for people with atrial fibrillation (AF). These include chemical and electrical cardioversion, catheter ablation, pulmonary vein isolation ablation, and more infrequently, AV node ablation and the insertion of a pacemaker.
Cardioversion is a procedure which aims to restore normal heart rhythm (sinus rhythm). There are two main types: chemical and electrical.
Dr Tim Holt explains what cardioversion is and when it is used.
Chemical (or pharmacological) cardioversion
This procedure uses drugs such as adenosine and flecainide, injected intravenously (through the vein), in the hope of returning the heart to normal sinus rhythm. David X, who had intravenous flecainide, said that he preferred chemical to electrical cardioversion, after experiencing both procedures. For him, electrical cardioversion was “a bit traumatic”, whereas chemical cardioversion was “a gentle way of getting back into sinus rhythm”.
After the first attempt at chemical cardioversion failed, Eileen was reluctant to try it again. The procedure was again unsuccessful.
Jeni, who has supraventricular tachycardia (SVT), readily agreed to having adenosine to stop uncontrollable palpitations. She explained the process.
This procedure, which is usually carried out as a day patient in hospital, uses an electric shock to activate the heart and return it to normal sinus rhythm. For some, electrical cardioversion successfully stops further AF episodes, possibly for weeks or even years, and so no further symptom control treatment is needed.
Eileen described what happens in cardioversion.
Cardioversion successfully restored Pauline’s heart rhythm.
Yet while cardioversion can have a good success rate in restoring normal heart rhythm, it does not always work.
Dr Tim Holt explains why cardioversion is not always successful.
People we spoke to were not always convinced about the value of having a cardioversion, or were disappointed in the results. Janet, recently diagnosed with AF, was unsure whether to go ahead after finding out the procedure had only been successful in 1 of 3 friends with AF; Mary decided against it when told cardioversion would involve “stopping the heart and then restarting it artificially”.
For others who underwent the procedure, the results were disappointing. Dot said she had “got away with” not having cardioversion after her heart reverted to normal sinus rhythm of its own accord.
Dave explained why he refused cardioversion.
Nuala had over 20 unsuccessful cardioversions before reaching a decision with her cardiologist to remain in AF and regulate her heart rate rather than rhythm.
Eileen underwent a number of cardioversions over the years, none of which worked for more than six weeks. She described the worst of these.
Ablation is a way of controlling AF symptoms and heart rate. Ablation procedures include catheter ablation, pulmonary vein isolation ablation, and AV node ablation and the insertion of a pacemaker.
With the exception of athletes, catheter ablation is not usually a first line treatment for people with AF. It may be offered, however, when a person experiences side effects or does not respond to medication, or when cardioversion has been unsuccessful. As Dr Tim Holt explains, although the aim of catheter ablation is to “control symptoms and heart rate, it is not yet clear whether these procedures will reduce the lifetime risk of having a stroke in the future.”
Usually performed in hospital by an electrophysiologist, catheter ablation involves destroying (ablating) faulty electrical pathways from the heart by freezing or burning the heart tissue. As Jeni described it, ablation involves “getting rid of the damaged or problematic tissue in your heart that sends the electrical current the wrong way”. This is done using a long wire (catheter) threaded into the heart. Once the tissue is treated in this way it forms a scar which can no longer conduct the abnormal impulses.
Glyn, who has had two unsuccessful ablations after medication failed to control his AF, described his experience.
Ginny, whose passion is mountaineering, explained her decision to have a catheter ablation. Although successful so far, she is unsure how long it will last.
Bob, who had two unsuccessful ablations, was delighted when the third attempt proved successful.
Bob reported that AF symptoms can take a few months to “settle down” after a catheter ablation. He now takes a small dose of flecainide and has not had AF for 18 months. He asked the surgeons not to ablate to such an extent that he might need a pacemaker, as he said that being an engineer, he did not trust technology to keep him alive.
Chris X initially rejected having an ablation procedure, but when he later changed his mind, found that his specialist and nurse were happy to discuss it in detail and then allow him to decide in his own time.
James, who had a stroke due to AF, had three ablations and said he felt a little better after each one.
James’s wife Jenny recalled how she found it “absolutely petrifying” when he had the ablations, but after the third ablation proved successful she acknowledged that “he was right that his quality of life was non-existent really. And if that is the case, you just do whatever it takes to get you back on track.”
Geoff spoke of breaking a record in his hospital in having 4 ablations, where the final one was successful. He planned to start reducing his medication soon. He noted that the need to come off his medication prior to each procedure sent his AF “haywire”.
David Y, who had a triple heart bypass, had an ablation conducted “while the surgeon had me open”. Six clots were found during the procedure, so he reported feeling very lucky that his surgeon had been able to remove these.
Gail was pleased that her second ablation appeared to be working. The procedure left her feeling traumatised.
Catheter ablations are not always successful. Elisabeth X, who turned down an ablation over 10 years ago when she was in her sixties and “didn’t think the odds of success were too good”, now believes she is “past the age” to have the operation.
Martin has been told that if his symptoms worsen, he can increase his dose of sotalol or consider an ablation. Aware that “the longer you leave it before having an ablation, the less successful it is deemed to be”, he has decided to take medication while it continues to work rather than “risk having an ablation”.
Glyn believes that his ablations may have failed because his medical team “left it too late” to decide “on some really serious action”. They carried out the first ablation 7 years after his diagnosis, which he felt made it harder to treat.
David X had a haematoma in his leg after both of his ablations, which he found “alarming”. He said he was reluctant to have a third ablation as he felt his heart had been “horribly abused”, and decided to wait and see if his AF would settle down. He continues to take medication for his AF.
Marianne decided to go ahead with an ablation, although her consultant warned her that it may not be successful and she may need to repeat the procedure.
Roger has had three ablations. Despite initial success in bringing the heart back into rhythm, they have all been unsuccessful long-term.
Pulmonary vein isolation ablation
Pulmonary vein isolation is another form of ablation used when medication fails to eliminate symptoms of AF caused by an irregular heartbeat, or in cases where people cannot tolerate medications. Performed under local anaesthetic with sedation, the procedure uses radiofrequency energy (heat energy) to destroy tissue around the four pulmonary veins. The resulting scar tissue, which takes from 2 to 3 months to form, blocks abnormal signals reaching the rest of the atrium (one of the two blood collection chambers of the heart). The procedure is not always successful and may need to be repeated.
Eileen had the procedure carried out privately. Despite its initial success, she went back into AF 6 weeks later.
After many failed cardioversion procedures, Nuala went on to have a pulmonary vein isolation ablation. She was disappointed when she went back into AF a few weeks later.
AV node ablation and pacemakers
In some cases medication or an ablation procedure are either not appropriate or are unsuccessful in restoring regular heart rhythms and people continue to experience AF symptoms. A third alternative is either to have a pacemaker fitted, or to have an irreversible AV node ablation and a pacemaker implant to prevent the heart rate falling too low. In this procedure the AV node is destroyed, leaving the person dependent on a pacemaker to take over their heart rhythm for the rest of their lives.
Some of the people we spoke to had had a permanent pacemaker fitted. This is a small metal box weighing 20–50g attached to one or more wires that run to your heart. The device uses electrical impulses to regulate the heartbeat. Fitting a pacemaker is a day surgery procedure and takes about an hour under local anaesthetic. It can have a positive effect in reducing the symptoms of AF and improving quality of life. After having a pacemaker implanted, people need to attend regular check-ups to make sure it is working properly.
Glyn, who had a pacemaker fitted after two failed ablations, described his recovery from the operation.
Raymond, who had a pacemaker fitted after collapsing several times, was delighted with the result.
Eileen had a pacemaker fitted after her pulse rate dropped below 30 and doctors advised her that “atrial fibrillation will never kill you but a very slow pulse will”. Despite having to restrict her arm movement so as not to “dislodge the wires” for 6 weeks after the operation, she described how her life had improved: “I can certainly walk upstairs, I can even make a bed without getting out of breath.” However, although she felt better she still experienced palpitations, and after consultation decided to have an AV-node ablation.
Eileen spoke about the psychological impact of having a pacemaker, but admitted that her quality of life had improved since having an AV-node ablation.
Although having an AV node ablation and pacemaker fitted can improve the quality of life for people with AF, they are irreversible procedures. This can have an effect on whether people decide to go ahead with the operation, and how they feel about the procedure afterwards.
Despite having had 3 unsuccessful ablations, Roger is not keen on having an AV-node ablation.
The sense of finality of having an AV-node ablation and pacemaker fitted was a factor in discouraging Nuala from having the procedure.
Despite having no regrets about having an AV node ablation and pacemaker, Eileen wonders whether she might have jumped the gun.
(For more see Heart rate and rhythm medication for atrial fibrillation.)