What is a cardioversion?
It is a treatment for heart rhythm disturbances to reset the rhythm back to normal using an electric shock. You will be given a brief general anaesthetic so that you will be unaware of the shock.
Treatment before cardioversion
Drugs are used to control the heart rate, such as bisoprolol (beta-blocker), diltiazem or digoxin. The blood is thinned using warfarin, aiming to reduce the likelihood of any clot forming in the weeks running up to the cardioversion.
Routine tests prior to cardioversion
A heart tracing (ECG, electrocardiogram) records the heart rhythm. An ultrasound scan of the heart (ECHO, echocardiogram) assesses the structure and function of the heart muscle and valves to identify underlying causes of heart rhythm disturbances. Blood tests check the blood strength (Hb, Haemoglobin) and biochemical screen (U&E, Urea and Electrolytes) are is satisfactory prior to admission for cardioversion. A nasal swab (MRSA screen) checks you are not carrying infections that could be passed on to others in hospital). Anticoagulation clinic monitoring (INR, International normalised ratio) checks your blood is thin enough to reduce the risk of a stroke. Aim to maintain the INR between 2.5 and 3.5 in the 4 weeks prior to cardioversion. If your INR drops below 2.0, please notify Dr Appleby’s secretary as we may need to reschedule the date for cardioversion.
On the day of your cardioversion
Attend the hospital in the morning starved from midnight. You will be admitted to the ward at 10am, have an ECG and complete the consent forms. You will meet the consultant cardiologist and consultant anaesthetist undertaking the procedure. Theatres will send for you at midday. The nurses will connect up the equipment and the anaesthetist will give you a brief general anaesthetic. Once fully anaesthetised, the consultant cardiologist will deliver a shock to reset the rhythm. Anaesthetics are not given at the Duchy by trainees. Cardioversion procedures at the Duchy are not undertaken by medical students, middle grade doctors, paramedics, nurses or other staff. After the procedure you will wake up in recovery and return to the ward. Relatives can expect you back on the ward by 1pm.
After the procedure
You will be allowed to go home a few hours after the procedure once you are alert, fully mobile and able to eat and drink. Please continue warfarin and your other regular medication. A friend or relative must collect you and take you home to keep a check on you the evening/night after the procedure. Do not drive, drink alcohol or operate machinery until the following morning. If you have any concerns, ring the main ward at the Duchy on 01423 561736. Dr Appleby will arrange to see you in clinic a week or two after the procedure. For the bookings desk, ring 01423 722117. Dr Appleby’s private secretary Jane Crewes can be contacted on 01423 531329 (Sarah when Jane is away).
Are there any risks?
Cardioversion is a very safe procedure. The mortality risk of a general anaesthetic is less than 1 in 10,000. Most patients are shocked from atrial fibrillation/atrial flutter to a normal sinus rhythm with a single shock, but 2 or 3 shocks may be required. The success rate for restoring sinus rhythm is initially 80-90%, but there is a risk of recurrent arrhythmias (30-50%) requiring a further procedure or medication. A skin reaction may occur around where the shock is delivered lasting up to a few days for which a cream can be used. The risk of a stroke is less than 1%, but there is also a risk of a stroke if you do not have the cardioversion procedure. The likelihood of maintaining a normal rhythm is higher if the heart is structurally normal, the onset of the rhythm was recent and there is an underlying correctable cause predisposing to the arrhythmia. If there are any specific additional risks with your case, this will be discussed at the time of booking for the procedure and prior to signing consent forms.
Any further queries?
The pre-assessment nurse will go through the procedure with you. Dr Appleby can be contacted via his private secretary on 01423 531329.