Sign in to your account

Don't have an account?

Create an account
This website uses cookies to ensure you get the best experience on our website. Learn more
Black medical doctor in a white coat and red stethoscope examining a patient on a ward. Our doctors on askawayhealth have years of clinical experience to provide top notch care.

Need to check your symptoms?

Use our symptom checker to help determine what your symptoms are and to ensure you get the help you need.

Check your symptoms


Request a reset

Don't have an account?

Create an account


Reset your password

Don't have an account?

Create an account


Abnormal Heart Rhythms and Sudden Death Explained

February 15, 2023

Contributed by Kate Macmorn

Doctors helping to revive people with collapse from abnormal heart rhythm

People with abnormal heart rhythms need to find the causes behind the irregularities.

Understanding an abnormal rhythm, the different types, risk factors, and causes can help prevent a person from sudden death. 

What Is An Abnormal Heart Rhythm?

An abnormal heart rhythm, also known as a heart arrhythmia, is an irregular heartbeat that occurs when the signals in the heart are not firing properly.

Suppose the electrical pulses within the heart are firing out of synchronization. In that case, this can cause pain, fluttering, anxiety, dizziness, or nausea. 

A heart arrhythmia is classed into two groups based on the speed of the heart:

  • Tachycardia — This is a fast heartbeat that is higher than 100 beats per minute (BPM).
  • Bradycardia — This is a slow heartbeat that is less than 60 BPM.
Doctor holding an artificial heart demonstrating heart conditions that lead to abnormal heart rhythm


Various types of tachycardia can affect a person’s heartbeat:

  • Atrial flutter — Atrial flutter is an “organized” flutter that can eventually lead to a stroke.
  • Atrial fibrillation — Also known as Afib, this unreasonable heart firing can lead to an uncoordinated heart rate.
  • Supraventricular tachycardia — This term includes arrhythmias that are caused by long periods of heavy palpitations.
  • Ventricular fibrillation — This type of arrhythmia causes the heart chambers to flutter, instead of contracting, limiting the blood flow to the extremity in the body. This problem, when left untreated, can lead to serious problems or death. 
  • Ventricular tachycardia — This tachycardia causes a rapid but regular heart rate that does not pump enough blood to the body. 


A heart that beats less than 60 beats per minute is considered a very slow heartbeat.

In some cases, this is very healthy and not considered a problem (ex: athletes, physical fitness, marines, etc.). However, in certain cases, bradycardia is a sign of one of the following illnesses:

  • Sick sinus — Sick sinus syndrome can cause the heart to alternate between too-fast and too-slow beats.
  • Conduction block — If the electrical pathways are too slow or stop altogether, this can cause an irregular and slow heartbeat. 

Symptoms of an Abnormal Heartbeat

Suppose you think that you may have tachycardia or bradycardia. In that case, there are signs and symptoms to look out for to help diagnose and treat your abnormal heartbeat.

Most heart arrhythmias cause a few noticeable symptoms, such as:

  • Chest fluttering
  • Tachycardia 
  • Bradycardia
  • Shortness of breath
  • Nausea
  • Dizziness
  • Chest pain
  • Anxiety
  • Fatigue

When You Should Seek Medical Help

If you are experiencing any of the above symptoms, it may be time to seek medical help and see a doctor. If it feels like your heart is beating irregularly, whether it be too fast or too slow, this is a warning sign that you should see a professional as soon as possible. Suppose you have more severe symptoms, like shortness of breath, chest pain, or lightheadedness. In that case, we recommend going to the emergency room.

Practicing CPR with AED and dummy

Causes of an Abnormal Heartbeat

There are many causes of an abnormal heartbeat.

Learning them can provide a patient with information regarding how a heart works, how to treat their illness, and how to prevent it from getting any worse.

The most common causes of an abnormal heartbeat are the following:

  • Heart attack — Blockage of blood in the heart that causes the tissues to lose oxygen, leading to fatigue, chest pain, and lightheadedness 
  • Coronary artery disease — Damage within the heat’s blood vessels that can lead to a plaque buildup and limited blood flow 
  • Cardiomyopathy — Hereditary heart disease that reduces the effectiveness of delivering blood to the rest of the body 
  • Diabetes — Disease with too much blood sugar
  • High blood pressure — Excess force of blood against the artery walls, which can lead to heart disease and stroke 
  • Hyperthyroidism — Excess thyroxine production that can cause weight loss, sweating, anxiousness, and irritability 
  • Sleep apnea — A sleep disorder that causes the body’s breathing to stop and start rapidly 
  • Hypothyroidism — Underactive thyroid gland, which can cause fatigue, constipation, and weight gain 
  • Drug abuse 
Electronic heart tracing in deep red colour

Causes of Sudden Death

If you are experiencing an irregular heartbeat, this can indicate ventricular fibrillation or V-fib.

V-fib can lead to a very fast drop in blood pressure, resulting in fainting, slow pulse, and deteriorated breathing. If this occurs, someone may collapse in seconds. 

Ventricular fibrillation is the most common cause of sudden cardiac death in patients with an abnormal heart rhythm.

If a person is not treated immediately through CPR and an automated external defibrillator, a person will be dead in just a few minutes. The uncoordinated heart rates will cause the blood to stop pumping, lowering the blood pressure, and damaging the body’s internal organs. 


Understanding the different types of heart rhythms can help a person self-diagnose.

As soon as you notice any dangerous warning signs, you should seek professional medical help.

Recognizing and diagnosing tachycardia or bradycardia can be the difference between lessening risk factors and being a victim of sudden death. 

Author Bio:

Kate Macmorn, Communications Director, AMRI

Kate is the communications director for the American Medical Resource Institute. They’ve trained over a million healthcare professionals to study for, earn and maintain life support certifications that allow them to better respond to cardiac emergencies. You can find Kate practising her tennis skills when not in the office. She also frequents live music venues and is always looking for her next creative hobby.

More Reading

Editing by AskAwayHealth Team


All AskAwayHealth articles are written by practising Medical Practitioners on various healthcare conditions to promote quality healthcare. 

The advice in our material is not meant to replace a qualified healthcare practitioner’s management of your specific condition.
Don’t hesitate to contact a health practitioner to discuss your condition or reach us directly 

Image Credits: Canva

Share this blog article

On this page

Let us know what you think

Want to know how your comment data is processed? Learn more

Access over 600 resources & our monthly newsletter.

Askawayhealth 2023 grant recipient from European Union Development Fund

Askawayhealth, 2023 Award Recipient

Our educational content meets the standards set by the NHS in their Standard for Creating Health Content guidance.

Askawayhealth aims to deliver reliable and evidence based women's health, family health and sexual health information in a way that is easily relatable and easy for everyone to access.

Askawayhealth symptom Checker tool image

Utilize our complimentary symptom checker tool to gain more information about any uncertain symptoms you might have.