Lenmed on the Pulse: Understanding Irregular Heart Arrhythmias

The health of your heart can largely be defined by both its rhythm and the speed of its beating patterns. A normal heart rate at rest, understood as the number of beats per minute (bpm), is usually around 60 to 100 bpm. A cardiac arrhythmia is defined as an irregular heart rate that occurs when electric impulses that control the heart  function abnormally. This often results in a heart rate that falls outside of this standard range. Arrhythmias affect around 1.5% to 5% of people worldwide. Their severity is best understood as a spectrum as some types of these heart irregularities remain harmless, while others can prove fatal. Such heart irregularities can be denoted and detected by a faster or slower than usual heart rate, as well as heart palpitations, flutters and irregular beats. The four heart arrhythmia types include Bradycardia, Tachycardia, Fibrillation and Premature Contraction.

Different Types of Heart Rhythm Disorders

1. Bradycardia

Bradycardia is characterised by a heart rate that is abnormally slower than 60 bpm. It is important to note that people who exercise regularly and are fitter than the average person may have heart rates that dip below the average 60 bpm threshold. Additionally, when sleeping, your heart rate may also enter this range, which is perfectly normal.

There are two main subtypes of Bradycardia:

Heart block 

The electrical signals of the heart are disrupted as they move from the upper chambers of the heart to the lower ones. There are three levels of severity that categorise this phenomenon. First-degree heart block remains relatively harmless, while second-degree and third-degree heart block require greater medical interventions. 

Sick sinus syndrome  

This heart rhythm problem is linked to the sinus nodes in the heart. The sinus nodes are responsible for regulating heartbeat. As a result, when they malfunction, a chain reaction is caused that interferes with the way a person’s heart beats.

2. Tachycardia

A faster-than-average, elevated heart rate of more than 100 bpm at rest is characteristic of Tachycardia. This can also be accompanied by an irregular heartbeat. When exercising, your heart rate can naturally rise above this level, which is why a resting heart rate is the correct metric that should always be used. 

Tachycardia can be categorised into three main subtypes:

Supraventricular tachycardia (SVT)

This form of Tachycardia is located in  the upper chambers of the heart, denoted by the name “supraventricular”. The word “supra” means above and “ventricular” refers to a certain location in the heart. While the sinoatrial nodes usually control one’s heartbeat, with supraventricular tachycardia, an electric impulse from outside this area triggers the heart to beat in a rapid and elevated manner. 

Sinus tachycardia

When your heart receives impulses to beat faster than 100 bpm, it is called sinus tachycardia. This can be triggered by anything from exercise to stress and is a normal response. However, if no underlying cause can be detected or diagnosed, then the condition is referred to as inappropriate sinus tachycardia (IST). It is most prevalent in women in their 30s and it is not usually life-threatening.

Ventricular tachycardia (VT)

If supraventricular tachycardia affects the upper reaches of the heart, then ventricular tachycardia impacts the lower chambers. Once again, this condition – also known as VT or V-tach – is associated with an erratic heart rate above the standardised 100 bpm.

3. Fibrillation

This type of arrhythmia is linked to palpitations in the heart, as well as sensations of fluttering or quivering. In addition, the heart can also skip and/or add a beat.

Atrial fibrillation

Also known as AFib, this condition is one of the most pervasive forms of arrhythmia, affecting millions of people each year. An abnormal heart rhythm, caused by disrupted electrical signals, triggers the atria in the heart to quiver. 

Ventricular fibrillation

Considered one of the most dangerous heart conditions, VFib entails the electric impulses responsible for regulating heart beat malfunctioning. This causes the heart to stop pumping blood to the rest of the body during the period that it quivers. As a result, prolonged VFib can quickly lead to cardiac arrest.

4. Premature contraction

This type of heart rhythm abnormality can be simply understood as an extra heart beat. They trigger a sensation of the heart fluttering or skipping a beat.

Premature atrial contractions (PACs)

These contractions that originate in the atria of the heart add a heartbeat that causes irregular rhythm patterns. In most cases, PACs prove to be very little cause for concern as they can go away without medical assistance. When they occur frequently, then medical intervention may be required. 

 Premature ventricular contractions (PVCs)

Like PACs, PVCs are also associated with an extra heartbeat – this time originating in the heart’s lower chambers. In much the same vein, they also occur frequently and are usually harmless. Prolonged PVCs should, however, be brought to the attention of a doctor.

Symptoms of Different Types of Heart Rhythm Disorders

The abovementioned irregular heart rhythm types can be linked to a myriad of physical symptoms, which can be experienced in isolation as well as en masse. Moreover, it is pivotal to note that an arrhythmic heartbeat can be experienced without any manifestation of physical, detectable symptoms. When symptoms are experienced, these include, but are not limited to:

• Chest pain
• Shortness of breath
• Lethargy or weakness
• Excessive sweating 
• Lightheadedness or dizziness
• A faster-than-average heart rate
• A slower-than-normal heart rate 
• Heart palpitations such as fluttering or irregular beats 
• Anxiety

Causes of Arrhythmic Heartbeats

Like most diseases and medical disorders, environmental, lifestyle and genetic factors all exert varying influences on the health of our hearts. Some of the overarching causes and increased risk factors of the various types of irregular heart rhythms, include:

• Blood clots
• High blood pressure
• Heart disease 
• Sleep apnea
• Electrolyte imbalance
• Viral infections 
• Obesity 
• Hypothyroidism
• Alcohol and smoking 
• Caffeine 
• Other medical conditions
• Certain medications

In Conclusion

Understanding the different types of heart arrhythmias is crucial for recognising symptoms and seeking appropriate treatments. By staying informed about these irregular heart rhythms as well as their causes and preventative measures, you can take proactive steps towards maintaining a healthy heart. Regular checkups and a heart-healthy lifestyle are essential in managing and reducing the risks associated with arrhythmias.

FAQs

How can individuals prevent or reduce the risk of developing irregular heart rhythms?

There are various lifestyle changes that can help mitigate the risk of heart arrhythmias. Limiting your intake of tobacco, alcohol and caffeine is particularly important as well as reducing stress and anxiety. Monitoring your blood pressure frequently can also be beneficial. Going for checkups may become imperative if you’re experiencing any consistently worrying symptoms.

What treatments are available for different types of heart rhythm abnormalities?

While the aforementioned lifestyle changes can be beneficial, following the instructions of medical practitioners is pivotal. This includes following the prescribed medical regimens. Specific treatments can include anything from implant surgeries to taking beta blockers.

How are heart rhythm disorders diagnosed by healthcare professionals?

There are several diagnostic methods used to detect these disorders. Blood tests, for example, can be conducted to assess hormone imbalances. Electrocardiograms and echocardiograms are also used to monitor one’s heart rate. A loop recorder that is implantable is another device that can be used to detect any abnormalities. Physical stress tests can also be performed.

For more information, please contact:
Dr C Mussagy
Discipline: Cardiologist
Hospital: Maputo Private Hospital
Telephone: +258 84 095 7900