Cardioversion

What is cardioversion?

Cardioversion is a treatment that steadies an irregular heartbeat, medically known as an arrhythmia, back into its normal rhythm. It's commonly used to treat atrial fibrillation or atrial flutter, though other fast or uneven heart rhythms can respond to it too.

What conditions does cardioversion treat?

Cardioversion can correct a number of abnormal heart rhythms, including:

• atrial fibrillation and atrial flutter, which make up the bulk of cases where this treatment is used
• atrial tachycardia
• ventricular tachycardia
• ventricular fibrillation.

When your heart’s rhythm is off, you might notice your chest thumping or fluttering, find yourself short of breath, feel discomfort in your chest, or become dizzy and unusually worn out. These point to your heart struggling to circulate enough blood, and left unaddressed, this can eventually contribute to a heart attack or a stroke.

What are the benefits of cardioversion?

Cardioversion usually succeeds in bringing the heart's rhythm back to normal, easing symptoms along the way and letting your heart do its job more effectively.

More than 90% of people who undergo the procedure see their rhythm return to normal straight away, while the chance of the procedure itself triggering a stroke sits at less than 1%.

Just how long that normal rhythm sticks around differs enormously from one person to the next, lasting years for some and considerably less for others, influenced by things such as how long you'd been living with the arrhythmia beforehand.

Are there different types of cardioversion?

There are two main approaches:

• electrical cardioversion: pads attached to your skin, on your chest and occasionally your upper back, deliver a measured jolt of current from a defibrillator; you might also hear this called DC (direct current) cardioversion
• chemical cardioversion: rather than a shock, medication does the work, taken by mouth or fed in through a drip, with results appearing anywhere from a few minutes to several days later.

Electrical cardioversion tends to be booked well ahead of time, although a severe case can occasionally mean it's carried out on the spot. It shouldn't be confused with defibrillation, the emergency response used when someone's heart has stopped, which relies on considerably stronger shocks than cardioversion does.

What happens before cardioversion?

Ahead of your appointment, you'll be talked through exactly what to do, which typically includes:

• keeping up your usual tablets, just with a small mouthful of water, unless you're told otherwise
• confirming with your doctor how to handle any blood-thinning or diabetes medicine on the day itself
• going without food for a set period beforehand, since a general anaesthetic is normally part of the process
• taking off jewellery and make-up, and keeping creams or oils away from your chest
• lining up a lift home, since getting behind the wheel yourself won't be an option for 24 hours afterwards.

• For anyone taking a newer type of anticoagulant, dabigatran, rivaroxaban, apixaban or edoxaban, sticking to the prescribed dose without fail for 3 to 4 weeks beforehand matters a great deal, since a gap in doses pushes up your stroke risk and could push back your appointment.

  A scan called a transoesophageal echocardiogram, done using a probe passed down your throat, is sometimes needed too, to rule out clots lurking inside your heart.

  What happens during cardioversion?

  1. A general anaesthetic sends you to sleep, so you won't be aware of anything that follows.
  2. Electrodes, sticky patches, are fixed onto your chest and sometimes your back, with any hair in the way shaved off first if needed.
  3. These connect through to a defibrillator, which sends a brief, precisely timed pulse of current into your heart.
  4. Throughout, a screen tracks your heart's rhythm, letting the team see immediately whether the treatment has taken effect.
  5. Occasionally, getting the rhythm back to normal can take more than one attempt.

  The actual treatment is over within a matter of minutes, though once you factor in getting ready beforehand and time to come round afterwards, plan for the whole visit to take somewhere between 4 and 6 hours.

  What does recovery look like?

  Staff will keep a close eye on you until you've fully come round from the anaesthetic. Feeling drowsy and a little sore across the chest for a few days afterwards is nothing out of the ordinary.

  • eating and drinking again is generally fine once you're properly awake
  • most people are discharged the same day
  • driving, alcohol and operating machinery are all off limits for the first 24 hours
  • you'll need someone responsible to get you home and stay with you.

  Before you're discharged, whoever's been caring for you will run through the outcome with you and confirm whether your usual medicines need to continue unchanged. Anyone taking a blood thinner beforehand should keep taking it exactly as advised, even once things look back to normal, since coming off it too early raises your stroke risk again.

  A further appointment will be arranged to check how the treatment is holding, and it's worth asking your doctor directly when you can safely get back to work or start exercising.

  What are the risks and complications?

  Complications are uncommon, but possible risks include:

  • the treatment failing to work, or your arrhythmia returning at a later point
  • redness or short-lived irritation on the skin where the pads sat
  • an allergic reaction to any medicine given
  • a clot dislodging and causing a stroke, though this is rare
  • your heart rhythm problem becoming worse rather than better.

  Should cardioversion not correct things, or your arrhythmia comes back, your doctor might suggest another attempt. After it's been tried a handful of times without lasting success, a different treatment route is usually recommended instead.

  Get in touch with your doctor promptly if breathlessness persists after your treatment, or if symptoms you had before start showing up again.