How is cardiac arrhythmia treated?

This is a difficult question to answer with any precision, because “arrhythmia” is not a precise diagnosis. Rather, the word is a collective term for a family of related conditions that alter the normal pattern of electrical activation of the heart during a heartbeat.

Arrhythmias tend to cause disruption of the heart’s usual pattern of beating, either making it too fast (the tachycardias) or too slow (the bradycardias). Just to mix things up a little more, all patients respond slightly differently to arrhythmias, so that a condition that causes an extremely fast beat (tachycardia) for one individual may lead to a normal or even a slow heartbeat in another individual. The underlying mechanism of rhythm disturbance could be exactly the same but the treatment required could be opposite, with the tachycardic patient requiring drugs to slow their heart, while the bradycardic patient might need a pacemaker to speed their heart up.

Some arrhythmias are serious - life threatening even. Others are benign. There is even one sort of heartbeat, commonly called an arrhythmia, that isn’t an arrhythmia at all but is actually a feature of a normal rhythm. If you find this confusing you are not alone. Most non-specialists struggle with this complex and contradictory area of medicine. It tends to attract nerds and geeks and pedants. Cardiac electrophysiologists are people who like classifying things; we are the butterfly collectors of the medical world.

But the classification really does matter! Some abnormal heart rhythms carry major risks of stroke, or of developing heart failure, or of dropping down dead without warning; independent of how the rhythm itself is managed, these other, life defining aspects, must be correctly identified and dealt with to minimise risk and maximize the chance of a long and healthy life, with or without your arrhythmia.

In general terms, the ideal treatment for an abnormal cardiac rhythm is to normalise it - to return it to an instrinsically even and metered rate, governed by the usual anatomical structures and usual physiological processes of heart rate control. However, this is not always possible.

Take atrial fibrillation (AF), for example: the most common arrhythmia. We know that once a patient has been in atrial fibrillation consistently for more than a year or so, then unless we can find and reverse an underlying cause, even the best electrophysiologists will struggle to maintain that patient in a normal rhythm in the long term. Although returning you to a normal rhythm may be the “best” option, it is not necessarily achievable, or may not be achievable at a level of risk that you find acceptable.

Other options therefore come into play.

In broad terms, the options for managing arrhythmias are very similar across all types of rhythm disturbance:

Option 1 is to maximise the chance of maintaining a normal rhythm by identifying and treating some reversible cause of the rhythm disturbance. The exemplar here is alcohol: alcohol worsens most arrhythmias. If I judge that alcohol is the cause of your heart rhythm problem then I will generally advise you pretty strongly to abstain from alcohol, and having done so there is a pretty good chance that your heart rhythm will improve and maybe even completely normalise.

Option 2 is to maximise the chance of maintaining a normal rhythm by taking medications, either regularly, or as and when you need them. The best example here is of a young otherwise healthy person with infrequent attacks of atrial fibrillation, who might simply need to take a dose of beta blocker and lie in a dark room for a while when they get their one attack of AF every three years.

Option 3 is to maximise the chance of maintaining a normal rhythm and minimise the frequency of abnormal attacks by having a medical procedure - an ablation. This option really only applies to arrhythmias that are characterised by excess, or dyscoordinate electrical activity. Within this general approach, however, different ablation strategies are possible. Broadly speaking, ablation procedures either seek to find and treat the electrical “trigger” for a period of abnormal rhythm, or deal with the “substrate” that allows the abnormal rhythm to sustain itself after the trigger has occurred. For example, the ablation of SVT, or supraventricular tachycardia, targets an electrical short circuit that allows the SVT to sustain. The main ablation strategy for atrial fibrillation, in contrast, targets the pulmonary veins that we know trigger off the majority of AF attacks in the majority of patients.

Many factors feed into the judgement of whether a patient is likely to do best with options 1, 2, or 3. The nature of the arrhythmia, published success rates for ablation, the prominence of symptoms, and the patient’s appetite for risk all have a bearing on the decision. And of course the decision may evolve over time: a patient can very easily start out relatively happy to put up with infrequent symptoms, but may get less happy to do so as the symptoms become more intrusive or more frequent.

There are, of course, some arrhythmias that should “always” (or almost always) be cured if the patient is agreeable. These are the exceptions, however; the extreme cases, where the downside to having recurrent attacks, and the potential upside to treatment, is so high that very few reasonable people would disagree. This is not the usual situation, however. Most rhythms and most treatments have a risk-benefit balance to be struck in most patients.

Option 4 involves a level of acceptance that not all abnormal rhythms can, or should, be normalised. Again, to take AF as an example: it is relatively common for patients to come to clinic for the first time already with very established atrial fibrillation that has been present for a long time and is obviously going to take many attempts at options 2 and 3 to get on top of. It is very reasonable in this situation to start to look at alternatives, and with AF in particular, the news here is pretty good: most people can achieve excellent symptom control even if they remain in AF for the rest of their lives. It might not be perfect, and it might require a couple of goes to get the strategy right for each individual patient, but the prospect for normality, or near-normality, is pretty good!

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You can read more about atrial fibrillation and other cardiac problems on the patient information pages at the Kent Heart Clinic https://www.kentlondoncardio.com.


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