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What are arrhythmias?


First, an arrhythmia is an alteration that does not have a physiological justification but that affects both the frequency and the heart rate. Remember that the frequency refers to the number of beats per minute and that the rhythm can be regular or irregular. Then, arrhythmias are disorders that affect the heart rate or frequency.

If the heart rate increases because we are nervous for a certain reason, it is not something pathological. It is simply that the frequency increases due to the tension caused by this tension. For example, when we are facing a threat.

On the other hand, if the alterations occur “for no reason”, that is, when we do not find a tangible reason for the increase in frequency, then it is considered to be pathological. In these cases is when you go to the doctor in search of a more comprehensive assessment.

Therefore, arrhythmias can be either increase or decrease in frequency; or also by alteration of the normal rhythm of the heart.

Arrhythmias are due to:

  • Disorders in the generation of beats.
  • Alterations in the conduction of the beats.
  • A combination of both.

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A tachyarrhythmia is a sequence of at least three beats at a frequency greater than 100 beats / minute.

Depending on the point where they originate, they are divided into:

  • Supraventricular : the origin is above the fascia of Hiss. On the electrocardiogram, narrow QRS complexes appear (
  • Ventricular : the origin is below the fascia of Hiss. Wide QRS complexes appear in the electrocardiogram (> 0.12 sec)



The atrial extrasystole occurs as a result of the presence of an ectopic focus in the atrium. An advanced depolarization occurs, which produces a heartbeat “before time”.

After the ectopic beat there is a brief pause, followed by a normal beat.

The atrioventricular extrasystole is produced by the appearance of an impulse at the level of the atrioventricular node. As a result , the atria are activated retrogradely and the ventricles are normal.

After the ectopic beat there is a compensatory pause, followed by a normal beat.

The extrasystoles are very frequent, in fact, they are the most frequent type of arrhythmia . They do not usually pose any kind of problem and do not require treatment.

We recommend you read: How to normalize the rhythm of the heart


  1. Sinus tachycardia It is a normal response to many situations, such as exercise, anxiety , pain, fever, caffeine consumption, among others. It is not necessary to specifically treat the tachycardia, only the cause that is producing it.
    In a sinus tachycardia simply increases the frequency at which the beats occur . In this case, the heartbeats originate in the sinus node, our “real pacemaker”, but at a frequency greater than 100 beats / minute.
  2. Atrial tachycardia This is what is known as a “heating phenomenon”. It originates in an atrial ectopic focus whose triggering frequency is higher than normal. This causes the normal focus to be inhibited and the ectopic focus to “take over” producing the heartbeat. It has a very characteristic layout.
    The heart rate increases progressively until it reaches a maximum, and progressively decreases again. It is treated with beta-blockers or calcium antagonists.
  3. Ventricular tachycardia . Its origin is located in an ectopic focus located below the fascia of Hiss. The main cause of the appearance of a ventricular tachycardia is an old myocardial infarction.



Atrial fabrication is the most common type of arrhythmia after extrasystoles.

It is characterized by a very fast, disorganized and desynchronized rhythm that causes ineffective atrial contractions. Since the atria do not contract as they should, blood stagnates inside.

  • The stasis of the blood increases the risk of thrombus formation , and with it, the risk of embolism. In fact, atrial fibrillation (AF) is the first cause of embolism (pulmonary embolism, cerebral stroke …)
  • By not filling the ventricles properly, the amount of blood the heart pumps to the body decreases.
  • As blood builds up in the atria, the pressure inside increases above the normal level. This can lead to the appearance of a pulmonary edema.

The treatment is focused on:

  • Go back to the sinus rhythm and slow down the ventricles.
  • Prevent embolisms.
  • Prevent the appearance of new episodes of arrhythmias.

Sinus rhythm is achieved by cardioversion, either electrical, or pharmacological. Controlled rhythm, beta-blockers are administered to control the frequency.

The prevention of embolisms is done by administering anticoagulants or antiaggregants. Recurrences are avoided by administering antiarrhythmic drugs.

Read also: 5 unexpected symptoms of a heart problem that you should know


Ventricular fibrillation is usually the result of rapid and repeated ventricular tachycardia . A disorganized, rapid and completely ineffective rhythm then appears that leads to asystole and death in a few minutes.

Time is fundamental. If a defibrillator is not available, it is necessary to start manual CPR until you have it. In this video you can see how to do CPR. Therefore, immediate electrical defibrillation is necessary to avoid patient death.




There is a decrease in the heart rate below 60, due to alteration of the sinus node , the “cardiac pacemaker”. Damage to the sinus node can be due to:

Currently, sinus bradyarrhythmia is the second most frequent cause of pacemaker implantation.


There is a delay in the transmission of the electrical impulse between the atria and the ventricles.

These arrhythmias are classified according to the degree of severity, from the first to the third:

  • First degree blocking: decreases the transmission speed of the impulses, but they do not block.
  • Third degree blocking: all electrical impulses are blocked. The atria of the ventricles are “disconnected”. The symptoms will depend on whether an “escape rhythm” is set in motion. It consists of the production of beats at a point below the blockade, which allows the cardiac cycle to continue. The implantation of a pacemaker is necessary.
  • Second degree blocking: part of the impulses are blocked and part is not. There are two types, block type 1, Mobitz 1 or Wenckebach, and block type 2 or Mobitz 2.

1. TYPE ONE: the driving speed decreases progressively until the transmission of one or more of them is blocked . Then the normal rhythm recovers. It is considered benign, and is asymptomatic.

2. TYPE TWO: the blockage appears suddenly. It is less frequent, but it is also more serious since it can result in a complete block. This blockage can follow a certain sequence or be variable. Normally, it requires the implantation of a pacemaker.