Cardiac Rhythm and SCA


There are lots of things that can cause a person to suffer a sudden cardiac arrest (SCA). While not all of these are related to problems with the heart’s functioning, the majority are. These causes are down to different cardiac rhythms – whether too fast, too slow or simply irregular.

More often than not, an abnormal cardiac rhythm is unpleasant but harmless. Doctors will often advise that you are safe to continue leading your normal life with or without medication. However, there are some cases where sufferers might need further treatment to prevent something more serious happening.

For those looking to learn more about the different types of cardiac rhythm and how they can be treated, we’ve put together a handy guide that should help break things down a little.

What is cardiac rhythm?

Put simply, cardiac rhythm is the way that your heart beats. An ECG (electrocardiogram) can determine whether this is normal or abnormal and, depending on the outcome, whether you might need further treatment in future. Abnormal rhythms are known as arrythmia – or sometimes dysrhythmia – and come in a number of different types with various symptoms.

What are the different types of cardiac rhythm?

There are lots of different types of cardiac rhythm disorders, ranging from the minor to those that are potentially life-threatening. Some of the most common arrhythmic types include:

  • Arterial Fibrillation – the most common type of arrythmia, known as AF, this is where your heart beats irregularly and faster than usual
  • Ventricular Fibrillation (VF) – the heart beats with rapid, erratic electrical impulses. This causes pumping chambers in the heart (the ventricles) to quiver uselessly, instead of pumping blood. There are many pre-cursors to VF, including heart disease.’
  • Ventricular Tachycardia (VT) – abnormal electrical signals in the ventricles cause the heart to beat faster than normal, usually 100 or more beats a minute, out of sync with the upper chambers.
  • Bradycardia – this is where your heart beats more slowly than normal
  • Heart block – with this, your heart beats more slowly and can cause sufferers to collapse
  • Supraventricular Tachycardia – arising in the heart’s upper chambers, sufferers experience abnormally fast heart rates

Which cardiac rhythm is likely to trigger sudden cardiac arrest?

Of all the various types of cardiac rhythms, the most likely to cause SCA is Ventricular Fibrillation. This is the most life-threatening form of arrythmia and is a condition that causes disorganised electrical activity in the heart – meaning it quivers rather than pumps. Ventricular Fibrillation leads to a loss of consciousness which can mean SCA.

Ventricular Fibrillation can be caused by numerous things – like coronary heart disease, valvular heart disease and Long QT Syndrome.

What happens if someone goes into Sudden Cardiac Arrest?

If someone goes into sudden cardiac arrest, whether due to their cardiac rhythm or for another reason, you should call 999 and begin performing CPR straight away. You should also ask for the nearest defibrillator, as this will dramatically increase their chances of survival.

An AED (automated external defibrillator) will monitor the patient’s heart rhythm and try to return it back to normal using shock treatment. The defibrillator will only shock once it detects arrythmia, so there’s no chance of accidentally shocking someone.

How do I know if I have cardiac rhythm problems?

You might have been suffering from a few symptoms that have you worrying about cardiac rhythm. These could include palpitations, dizziness, blackouts and light-headedness. If you have been suffering from any of these symptoms, you should visit your doctor. They may refer you to a specialist for an ECG to record your heart’s electrical activity.

How can you manage cardiac rhythm?

If you are diagnosed with cardiac rhythm problems, your doctor will refer you to a specialist who will be able to help you further with day-to-day management.

Specialists will perform a diagnostic procedure to determine which type of disorder you have. This might include Holter monitoring – where a portable device is fitted for 24 hours – a Tilt table test to reproduce the causes of your blackouts, or even keyhole surgery to find and treat the cause of your cardiac rhythm disorder.

Treatments will vary depending on what type of disorder you are diagnosed with, but these might include fitting a pacemaker, implanting a defibrillator device, or heart failure therapy.

Get in touch

A defibrillator could significantly reduce the risk of deaths due to SCA. To find out more about getting one for your school or workplace, get in touch with our team.