Cardiac arrhythmias: supraventricular extrasystole

By Cristiano Antonino On May 2, 2023

Supraventricular extrasystole is a cardiac arrhythmia. This pathology is characterised by cardiac contraction impulses appearing prematurely and in a different location than the atrial sinus node

Literally the term extrasystole means ‘added beat’, it is also referred to as a premature or ectopic beat.

Extrasystoles can appear sporadically and be isolated phenomena or occur continuously.

In this case, we speak of extrasystoles in pairs or triplets.

These phenomena may alternate with one or more normal beats.

The heart rhythm in this case is identified as bigeminal, trigeminal or quadrigeminal, depending on the extrasystole-normal rhythm.

In general, extrasystole is the most common of cardiac arrhythmias and can occur in healthy individuals as well as in heart patients, i.e. those with heart disease.

The causes of supraventricular extrasystole are diverse and are linked to the patient’s state of health.

In a heart patient, this disease is linked to the condition of the heart, whereas in a healthy individual it can be linked to various factors such as alcohol and coffee abuse, smoking, and physical and mental stress.

Diagnosis usually comes after an electrocardiogram and treatment is linked to the presence or absence of heart disease.

Supraventricular extrasystole: what is it?

Supraventricular extrasystole is an arrhythmia of the heart.

This condition results in abnormal cardiac contraction impulses compared to those induced by a sinus rhythm.

The condition is characterised by appearing prematurely in relation to the normal stimulus, so that it interferes with the conduction of the impulse.

The disorder is often ectopic in origin, meaning that the impulse has a different location from the atrial sinus node.

Such elements interfere with the normal sinus rhythm.

Extrasystoles are very frequent arrhythmias, so much so that several studies have shown that, at least once in their lifetime, every individual has had an episode of premature or ectopic systole.

Extrasystoles can be

Sporadic – when they refer to a single, isolated phenomenon;
Paired – when two extrasystolic phenomena occur one after the other;
Blanks – when three or more extrasystolic episodes occur one after the other.

In some patients, a kind of alternation between extrasystoles and normal beats may occur.

In these cases it is called a rhythm:

Bigeminy – when there is an alternation between normal heartbeat and extrasystole.
Trigeminal – when systolic triads occur with one normal beat and two extrasystoles; or with two normal beats and one extrasystole.
Quadrigeminal – when four systoles occur, consisting of one extrasystole and three normal beats.

Extrasystoles are also distinguished according to their site of origin.

We therefore find:

Sinus extrasystoles – In this case, the premature beat originates in a part of the atrial sinus node that is slightly different from the dominant part. This is a rather rare condition.
Atrial extrasystoles – The premature contraction signal in this form of extrasystole originates from anywhere in the atrium musculature.
Atrioventricular junctional extrasystoles – Infrequent, they are linked to the appearance of the premature beat in the bundle of His, i.e. between the atria and ventricles, or near the atrioventricular node. The impulse is generated between two cardiac cavities and may propagate towards both, first stimulating the atria or the ventricles. The impulse therefore has a disordered and uncontrolled conduction.
Ventricular extrasystoles – These are the most common and frequent premature systoles. They originate at one point in the ventricles and propagate into the atria. The ventricular extrasystole is followed by the sinus stimulus encountering an insensitive myocardium due to the stimulus just received. This results in a lack of response to the normal beat. The absence of muscle receptivity results in a compensatory pause, which is referred to as ‘loss of beat’.

Supraventricular extrasystole: causes

The causes of supraventricular extrasystole are varied and are mainly linked to the state of health of the individual suffering from it.

This phenomenon should not be understood as indicating the presence of a heart disease, as it is not clinically relevant to the cardiologist, especially if it occurs in a healthy patient.

Factors that lead to the onset of this condition are smoking, alcohol, coffee or tea abuse.

Other causes are states of fatigue and physical and mental exhaustion, anxiety, use of anxiolytic drugs, sympathetic or vagal reflex stimulation from the abdominal organs.

Extrasystoles often occur in pregnant women, with a fair frequency up to delivery.

After completion they cease permanently.

In the absence of other symptoms that may indicate heart disease, they should not cause concern.

The situation varies in the case of extrasystoles that are associated with heart disease.

In this case, greater attention is required because the cause of the phenomenon is a heart disease.

A supraventricular extrasystole, in fact, may be a sign of more serious conditions, such as atrial fibrillation or atrial flutter.

The most dangerous circumstance remains when ventricular extrasystole induces ventricular fibrillation.

Related diseases

Supraventricular extrasystole can be linked to heart diseases such as heart failure, ventricular hypertrophy, myocardial infarction and valvulopathies.

There are also other diseases that can cause extrasystoles such as hyperthyroidism, gastrointestinal diseases (especially gastroesophageal reflux), hypertension and electrolyte imbalances (hypokalaemia; hypercalcaemia and hypomagnesaemia).

Supraventricular extrasystole: what symptoms does it present?

Supraventricular extrasystole is usually not felt by the patient, especially in the case of minor manifestations.

In general, the sensation of a stronger heartbeat or missing heartbeat is perceived.

When extrasystoles occur in blanks – i.e. with three consecutive premature systoles – the disorder is more easily felt.

Other symptoms are dizziness, heart palpitation, a feeling of discomfort in the chest, nausea, weakness and pallor.

Diagnosis

It is not always easy to diagnose the presence of supraventricular extrasystoles.

Therefore, a thorough cardiological examination is necessary.

The doctor will perform an objective test during which he will measure the pulse and listen to the heartbeat.

He will then usually prescribe some useful tests to assess extrasystolic episodes.

These include the electrocardiogram (ECG) and the dynamic electrocardiogram according to Holter.

By measuring the pulse, the cardiologist can gather vital information.

During the examination, the arterial pulse is measured to assess the regularity and frequency of the heart rhythm.

Stethoscopy, on the other hand, consists of auscultation of noises or murmurs and is very useful for distinguishing, for example, an aortic valve stenosis from one of the atrioventricular or pulmonary valves.

The electrocardiogram (ECG) is an excellent instrumental test to determine the quality of the heart’s electrical activity.

By studying the tracings, the physician can estimate the causes and severity of extrasystoles.

The dynamic electrocardiogram according to Holter is recommended for a more in-depth diagnosis.

This is a normal ECG, but involves continuous monitoring for 24-48 hours.

The patient is then monitored while going about his or her normal daily activities.

It is prescribed if the extrasystolic episodes are unpredictable and rather sporadic.

In the case of supraventricular extrasystole, the medical history plays a key role.

During the examination, the doctor will try to gather information by asking the patient to describe the symptoms experienced during the extrasystolic episodes.

Supraventricular extrasystole: possible treatments and therapies

If supraventricular extrasystole occurs in individuals who have no other cardiac disorders, no specific therapy is required, even when the events are frequent.

Nevertheless, the doctor will recommend improving certain habits, decreasing alcohol and caffeine consumption, eliminating smoking and reducing stress and anxiety without resorting to drugs.

The discourse changes in the case of individuals suffering from supraventricular extrasystole associated with a heart disease.

Therapeutic treatment becomes essential to preserve health. Medications that aim to normalise the heart rhythm are often prescribed.

When this condition depends on a heart disease, specific treatment is also possible.

Transcatheter radiofrequency ablation is performed using a catheter that is led up to the heart.

Once in place, it infuses a radiofrequency discharge into the area of myocardium causing the extrasystole, inhibiting its activity.

In some cases, surgical treatment is chosen instead, depending on the diagnosed heart disease.

If the patient is suffering from aortic stenosis, for example, the operation will aim to restore the valvular function of the heart.

If the extrasystole does not originate from a heart disease, treatment will be linked to the cause of the problem.

Supraventricular extrasystole: prevention

Supraventricular extrasystole can be prevented by eliminating the risk factors for this condition and those that could lead to heart disease.

For example, it is advisable to eliminate smoking, reduce the consumption of alcohol and anti-anxiety medication, engage in regular physical activity, and watch your diet.

Finally, it is important to avoid conditions that can cause excessive stress to body and mind, thus protecting one’s well-being.

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