AVNTR: AV nodal re-entry tachycardia (cardiac arrhythmia)

AVNTR or AV nodal re-entry tachycardia is a type of cardiac arrhythmia. Something then goes wrong when transmitting electrical impulses through the AV node in the heart. This can lead to a very high heart rate and even fainting. AVNTR is often treated with medication. If this does not work well or if a permanent solution is desired, an ablation is chosen. This is a surgical procedure in which one of the irritant connections that causes the problem is burned away. After this procedure, the use of medication becomes unnecessary and, if all goes well, you will no longer have seizures.

AVNTR, a type of heart rhythm disorder

  • About cardiac arrhythmias
  • Normal heart rate
  • Palpitations
  • When is something a heart rhythm disorder?
  • AV nodal re-entry tachycardia (AVNRT)
  • Symptoms
  • Treatment: medication or ablation

 

About cardiac arrhythmias

Cardiac arrhythmia or dysrhythmia is a collective name for a wide range of conditions that indicate a disturbance of the heartbeat. This can be something relatively harmless – such as the occasional ‘skipping’ of a beat – but can also be a serious condition, for example when there is trifibrillation and the pumping function of the heart is insufficient.

Normal heart rate

During a normal heartbeat, an electrical impulse occurs in the sinus node approximately once per second that causes the heart muscle cells to contract. This stimulus then spreads across the atria. The AV node is also located between the atria and chambers of the heart. This holds the electrical stimulus briefly to give the chambers of the heart time to fill with blood. The AV node then transmits the stimulus to the ventricles via the bundle of His, the bundle branches and the Purkinje fibers. The contraction of the chambers ensures that blood is pumped from the heart to the organs.

Palpitations

Some people regularly suffer from ‘palpitations’. This is said to occur when the heart beats irregularly or pounds excessively. This is a normal reaction of the body to certain stimuli such as emotions, heavy exertion, fatigue, spicy food, alcohol, medicine or drug use or staying at altitude. There may also be an underlying medical cause such as a thyroid problem, high blood pressure, anemia or hyperventilation. Women who are going through menopause can also experience heart palpitations. Although this gives an unpleasant feeling, it is usually harmless.

When is something a heart rhythm disorder?

With heart rhythm disorders, the complaints are often more serious and this can pose a threat to health. We speak of cardiac arrhythmias when there is actually a problem in the circuit that transmits electrical impulses in the heart. This can cause the heart to beat very quickly (tachycardia), to beat very slowly (bradycardia), to beat very irregularly or to cause the atria and chambers to no longer work together properly. Although cardiac arrhythmias do not necessarily lead to complaints, it can cause an anxious and agitated feeling, chest pain, shortness of breath, shortness of breath, tingling in the limbs, headache, dizziness and fainting. Sometimes this goes away on its own, but often medical intervention is necessary to get the heart back into a normal rhythm. Sometimes this can be achieved with medication, but it may also be necessary to administer an electric shock to the chest to bring the heart back into line.Types of cardiac arrhythmias There are many different types of cardiac arrhythmias. Examples of this are:

  • Sick sinus syndrome
  • Brugada syndrome
  • Wolff-Parkinson-White syndrome
  • AV block
  • Atrial fibrillation
  • Atrial flutter
  • Chamber tachycardia
  • Inappropriate Sinus Tachycardia (IST)
  • Catecholaminergic Polymorphic Ventricular Tachycardia (CPVT)
  • Long QT syndrome (LQTS)
  • Arrhythmogenic Right Ventricular Dysplasia (ARVD)

 

AV nodal re-entry tachycardia (AVNRT)

AV nodal re-entry tachycardia or atrio-ventricular nodal re-entry tachycardia – often abbreviated to AVNTR – is a type of cardiac arrhythmia that starts in the AV node and leads to an excessive heart rate. Normally, the AV node causes a delay in the transmission of an electrical stimulus to give the ventricles time to fill with blood so that it can be pumped around the body. If there is AVNTR, there are not one but two bundles in the AV node that conduct this electrical stimulus, one fast and one slow. These together form a circle in which the stimulus circulates. The stimuli are sent from the atrium to the ventricles and back again. This is called re-entry. This causes the atria and ventricles to contract quickly and simultaneously. This leads to a very high heart rate and can lead to dizziness and even fainting. The condition can be diagnosed by doing an ECG (electrocardiogram) or electrophysiological examination (EFO).

Symptoms

AVNTR can develop at an early age and is more common in women than in men. The condition comes on in attacks. Such attacks can occur suddenly, even when one is at rest, for example. The heart rate then increases but remains regular. Characteristically, the veins in the neck swell very much. It can also cause headaches, dizziness, chest pain, shortness of breath and fainting. An attack may go away on its own, but medical intervention may be necessary. The medicine adenosine is then administered in the hospital.

Treatment: medication or ablation

AV nodal re-entry tachycardia can be controlled with medication. Beta blockers or calcium blockers are often prescribed to slow down the stimuli conducted via the AV node and thus prevent the problem. Unfortunately, this doesn’t work for everyone. In AV nodal re-entry tachycardia that is difficult to control with medication, surgical intervention is often chosen. This concerns an ablation. This is a type of procedure in which one of the two excitatory connections in the AV node is burned away. Although this sounds dangerous, it is an operation that is performed relatively often and is considered to be of little risk. In approximately 0.05% of cases, the second stimulus connection is also affected during the procedure, which can lead to an AV block. In that case, the insertion of a pacemaker is necessary.

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