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Arrhythmias

We call arrhythmias the disorders of the formation and conduction of electrical stimuli that maintain cardiac activity.

They usually alter the rate and rhythm of the heart’s contractions, causing symptoms, but they may also only be detectable by an electrocardiogram (ECG).

The electrical stimuli of the heart are generated in an area of ​​the heart called the “sinus node.” This node forms stimuli with a frequency of 60-80 per minute. From here, the stimulus passes to another area called the atrioventricular (AV) node, through a “network of leads.”

In the AV node, the stimulus is delayed to allow time for the ventricles to fill with blood. The stimulus then proceeds through another “network of leads” (bundle of His, its branches, and Purkinje fibers), which branches through the ventricles, activating them and producing ventricular contraction. If the sinus node, which is the one that generates the stimuli, does not work, it is the AV node that takes this function, generating stimuli with a frequency of 45-50 per minute. When this happens it is said that the heart does not have a normal sinus rhythm, but is a “union rhythm”. Likewise, it may happen that neither the sinus node nor the VA function, generating stimuli from the ventricle at a rate of 30-40 per minute. This is called an “idioventricular rhythm.”

The formation and conduction of stimuli is influenced by different factors, including the nervous system (sympathetic and parasympathetic), increasing or decreasing the frequency of formation and conduction.

Causes of arrhythmias

  1. As we have previously commented, the heart rate can increase or decrease due to different stimuli until it exceeds certain limits and thus have bradycardia (heart rate less than 60 beats per minute) or tachycardia (rate greater than 100 beats per minute). When the formation of impulses by the sinus node decreases and the rate falls below 40-50 per minute, the stimuli are formed by the AV node or the ventricular tissue, which produces this type of arrhythmia called escape rhythms.
  2. Other times, an arrhythmia may occur due to an alteration in the conduction of the stimulus, interrupting this and appearing a blockage. Occasionally, some patients may present aberrant conduction of the stimulus without following the previously exposed pathway, presenting abnormal bundles that directly connect the atrium and ventricle on the same side or the atrium with the bundle of His, producing arrhythmias.
  3. On other occasions, the production mechanism is the perpetuation of an impulse, circling a closed circuit, within an area of ​​the heart. It is the mode of production of the vast majority of rapid arrhythmias or tachyarrhythmias.

What symptoms appear

It can be very varied, from the total absence of symptoms to sudden death. The most frequent symptoms are:

  • Palpitations: a pounding sensation in the chest or neck. Tachycardias usually produce sustained palpitations, in the form of a continuous pounding. There may be a feeling of flushing, dizziness, syncope or loss of consciousness, a feeling of suffocation and tightness or chest pain.
  • Cardiac arrest: it is produced by ventricular fibrillation that consists of a total disorganization of ventricular activation, being the most frequent mechanism of sudden death. It usually occurs in patients with previous severe heart disease.
  • Neurological symptoms: such as dizziness, loss of consciousness and seizures, associated or not with other neurological manifestations. These symptoms occur mainly in bradycardias.
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Other times arrhythmias can manifest as heart failure, with symptoms such as asthenia, fatigue or a feeling of suffocation and swelling in the legs.

Diagnosis of arrhythmias

An adequate medical history should always be taken to know if there are factors that predispose to arrhythmias, if there is any disease or alteration in the heart or symptoms that accompany the arrhythmia.

The frequency and type of presentation may suggest one type or another of arrhythmia. The diagnosis is made through an electrocardiogram (ECG), which allows us to see if there are alterations in it. It is also possible to diagnose and observe the evolution of an arrhythmia, doing what we call a “monitoring” of the patient, so that the patient is connected to a cardiac monitor, which continuously displays the ECG.

Another mode is called HOLTER, which is continuous monitoring during the normal life of the patient, outside the hospital, by means of portable ECG recorders, which the patient wears attached to a belt, for 24 or 48 hours. It is important for the patient to record all the symptoms and activities that he or she performs in a diary in order to establish a correlation.

Another more complex diagnostic method, but currently available, is the performance of an “invasive” study, which consists of the introduction of a catheter through a blood vessel until it reaches the heart, recording rhythm alterations in detail, and can serve as a therapy.

Treatment

The treatment of arrhythmias is based on the use of “antiarrhythmic” drugs that must be planned with clear objectives and carried out with periodic and adequate controls. The administration of antiarrhythmic drugs, in addition to orally, can be done intravenously, which should almost always be slow and with ECG monitoring.

Another way to treat arrhythmias is what we call electrical cardioversion, which consists of the application of electrical currents to the chest and which when applicable and indicated are the most effective.

For the treatment of bradycardias with severe symptoms, a pacemaker can be implanted. If there is any anatomical alteration that triggers the arrhythmia, it can be “cut” through surgery or by inserting a catheter until it reaches the heart and discharging different types of currents.

The best preventive measure is to lead a healthy life, without stress or nervousness to avoid the appearance of tachycardias, and not to consume stimulant drugs in the case of tachycardias or depressant drugs in bradycardias. Faced with the perception of any type of rhythm alteration, such as the appearance of palpitations for no obvious reason, it is advisable to see a doctor due to the vital importance of early detection.

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Hello Readers, I am Nikki Bella a Psychology student. I have always been concerned about human behavior and the mental processes that lead us to act and think the way we do. My collaboration as an editor in the psychology area of ​​Well Being Pole has allowed me to investigate further and expand my knowledge in the field of mental health; I have also acquired great knowledge about physical health and well-being, two fundamental bases that are directly related and are part of all mental health.

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