Abnormal heart rhythms, also known as arrhythmias, occur when the electrical signals that control the heartbeat become irregular. This may cause the heart to beat too fast, too slowly, or in an uncoordinated way. Many people experience rhythm disturbances at some point in their lives, and not all are dangerous. However, some require careful assessment to determine whether treatment or monitoring is needed. Understanding the different types of abnormal heart rhythms helps explain symptoms and reduces unnecessary anxiety when palpitations or irregular heartbeats are noticed.
How the heart’s rhythm is controlled
The heartbeat is regulated by an electrical system that begins in the natural pacemaker of the heart and travels through specialised pathways. This system ensures that the upper and lower chambers contract in a coordinated way. When this electrical signalling is disrupted, an abnormal rhythm can develop. The effect depends on where the disturbance occurs and how it alters the timing of heartbeats.
Fast heart rhythms
Fast heart rhythms are known as tachycardias. They may originate in the upper chambers of the heart or the lower chambers.
– Supraventricular tachycardia
Supraventricular tachycardia refers to fast rhythms that arise from the upper chambers of the heart. These episodes often start and stop suddenly and can cause palpitations, breathlessness, dizziness, or chest discomfort.
Episodes may be triggered by stress, caffeine, or exertion, but they can also occur without an obvious cause. Many forms are benign, although frequent or prolonged episodes may require treatment.
– Atrial fibrillation
Atrial fibrillation is one of the most common abnormal heart rhythms. In this condition, the electrical activity in the atria becomes chaotic, leading to an irregular and often rapid heartbeat.
Some people feel palpitations or fatigue, while others have no symptoms. It is important to identify because it increases the risk of stroke and may require treatment to control heart rate and reduce clot risk.
– Atrial flutter
Atrial flutter is similar to atrial fibrillation but involves a more organised electrical circuit in the atria. It can cause rapid heart rates and similar symptoms.
Although less common than atrial fibrillation, atrial flutter is managed in a similar way and also carries a risk of stroke.
Slow heart rhythms
Slow heart rhythms are referred to as bradycardias. These occur when the heart rate is slower than normal or when electrical signals are delayed.
– Sinus bradycardia
Sinus bradycardia occurs when the natural pacemaker of the heart generates signals more slowly than usual. This can be normal in fit individuals, particularly during rest or sleep.
In some cases, however, it can cause dizziness, fatigue, or blackouts, especially if the heart rate does not increase appropriately during activity.
– Heart block
Heart block occurs when electrical signals are delayed or interrupted as they travel from the upper to the lower chambers of the heart. The severity varies.
Mild forms may cause no symptoms and require no treatment. More advanced heart block can lead to significant slowing of the heart rate and may require a pacemaker.
Extra beats
Many people experience occasional extra heartbeats. These can arise from either the upper or lower chambers and are often described as missed beats or brief flutters. In most cases, extra beats are benign and do not indicate heart disease. They may be more noticeable during stress, illness, or after caffeine or alcohol. Assessment is important when extra beats are frequent or associated with other symptoms.
Ventricular arrhythmias
Abnormal rhythms arising from the lower chambers of the heart are known as ventricular arrhythmias. These are less common but can be more serious. They are more likely to occur in people with underlying heart disease or previous heart damage. Symptoms may include palpitations, dizziness, or collapse. Investigation and management depend on the type of rhythm and the overall condition of the heart.
How abnormal heart rhythms are diagnosed
Diagnosis usually begins with an ECG. Because many arrhythmias are intermittent, longer term ECG monitoring is often required. Echocardiography is commonly used to assess heart structure and function, as underlying heart disease influences both risk and treatment decisions. Exercise testing or additional imaging may be used when symptoms occur with exertion or when further clarification is needed.
Treatment and management
Treatment depends on the type of abnormal heart rhythm, symptom severity, and underlying heart health. Some rhythms require reassurance only. Others may be managed with medication, catheter based procedures, or pacing. The aim is to control symptoms, reduce risk, and improve quality of life. Not all abnormal heart rhythms need treatment, and unnecessary intervention is avoided where possible.
When to seek advice
It is sensible to seek assessment if palpitations are frequent, prolonged, associated with dizziness or blackouts, or occur during exercise. New or worsening symptoms should always be reviewed. If you have been told you have abnormal heart rhythms, or if you are concerned about palpitations or irregular heartbeats, you can book an appointment with me through our appointments & bookings page directly with the clinics i see patients at. Abnormal heart rhythms are common and often manageable. Careful evaluation helps distinguish between benign rhythm changes and those that require treatment, allowing reassurance or intervention where appropriate.