Supraventricular arrhythmias are relatively frequent changes of rhythm, often persistent, rarely severe enough to endanger the survival of the patient. They originate from the sinus node, atrial tissue or junctional sites between the atria and ventricles.



Concepts of physiology

Normally, the heart's electrical activity has an orderly and regular sequence, by way of atrio-ventricular (AV node), this normal electrical operation is a prerequisite for the smooth contraction of the heart.

Under physiological conditions:

Sinus: origin of the pulse

internodal pathways: 0.003 seconds delay

AV node: delay 0.09 seconds

AV bundle of His: 0.04 seconds delay

Pre ventricular delay: 0.16 seconds

ventricular Purkinje system: delay 0.03 seconds

myocardium and endocardium: 0.03 seconds delay

Post-ventricular delay: 0.06 seconds

Total pulse delay: 0.22 sec (220msec)



Sometimes, the "flow" electric locks in certain areas, or travel in certain paths repeatedly, creating a "short circuit" that disturbs normal heart rhythm. The medications may provide some temporary remedy, but the most effective and definitive treatment is to "destroy" the area of tissue that is causing the short-circuit. This procedure is cardiac ablation.

Ablation is a non-surgical procedure, and like many modern interventional cardiac procedures, requires no surgical cut in the chest. Rather, ablation is a relatively non-invasive procedure that requires the inclusion of Lead-thin, flexible wires-in the blood vessels, usually from the vessels of the groin or neck and from there go to the heart.



Aritmogenesi.



The rhythm is normal sinus or NS when the pacer generates so its physiological action potentials, acting as the main pacemaker depolarizing the pacemakers and more distal, and its frequency in this case is between 60-100 b / m, the arrhythmia can be defined as an alteration of the normal automatic and / or normal operation of other electrical pacemakers. It may happen that as a result of diseases of the myocardium, determine the discharge of other cells in the myocardium and thus have an "abnormal automatism" or particular functional stress that enhance or depress the activity of the specific myocardium, resulting in "abnormal automatism". The same happens when myocarditis, miocardiosclerosi, drug intoxication, hypoxic stress that could lead to a potential to reach the threshold that could trigger action potential and will, in this case, "triggered activity." If instead of functional or organic conditions hinder and block the conduction of electrical impulses to the myocardium, it will have "abnormal run". In that regard, if an impulse is not conducted in a uniform manner, because it meets the fabric that slows the progression of anterograde, once the same is out of the refractory period, the same impulse can go back give rise to the phenomenon of "return." If, however, take the fastest of accessory pathways, eg. bundle of Kent, we have the "pre-excitation." The term "supraventricular arrhythmia" is usually used for supraventricular tachycardia and atrial flutter. The term "supraventricular tachycardia" generally includes atrial tachycardia, the reentrant tachycardia atrioventricular node and atrioventricular reciprocating tachycardia, an entity which in turn includes the Wolff-Parkinson-White. Atrial fibrillation represents a distinct entity. Depending on the type of arrhythmia, I'ablazione catheter is a treatment option that can be taken at the time of initial diagnosis after symptoms appear, or following the failure of medical therapy. The catheter ablation of supraventricular tachycardia, atrial flutter and atrial fibrillation has a high rate of efficiency, long-lasting therapeutic endpoint (often lifelong), low complication rates.
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When the ablation is appropriate?

Many patients have rhythm disturbances that can not be cured with drugs, or some patients can not or will not take antiarrhythmic drugs for life, because of side effects of medications that can interfere with the normal quality of life.

Typically, the ablation is used to treat tachycardias that originate in the atria. As a group, these are known as supraventricular tachycardias and are:

-AF

Atrial Flutter-

-Re-entrant tachycardia in the atrio-ventricular node

-Atrioventricular reentrant tachycardia (WPW)

Atrial-Tachycardia

Supraventricular arrhythmias are a family of cardiac arrhythmias including the supraventricular tachycardia and atrial flutter. These arrhythmias are frequent, often persistent, and are rarely severe enough to endanger the survival of the patient. Supraventricular arrhythmias originating from the sinus node, atrial tissue from junctional sites located between the atria and ventricles, and can be treated with medication or catheter ablation. The term "supraventricular tachycardia" generally includes atrial tachycardia, the atrioventricular node reentrant tachycardia and atrioventricular reciprocating tachycardia. Atrial fibrillation represents a distinct entity.

The treatment of these arrhythmias may include the administration of antiarrhythmic drugs, but often lack efficacy, are associated with side effects and predispose to multiple drug interactions. An important treatment of supraventricular arrhythmias is different from 'catheter ablation. This intervention is able to handle safely, or even cure many common arrhythmia, is characterized by an excellent efficacy and avoid side effects long-term, often significant, of anti-arrhythmic drugs. L 'catheter ablation is a treatment of choice for many supraventricular arrhythmias, such as re-entrant tachycardia of atrioventricular node, atrioventricular reciprocating tachycardia, symptomatic atrial flutter and atrial tachycardia or symptomatic incessant. L 'catheter ablation of cardiac arrhythmia is conducted in a laboratory for cardiac electrophysiology, in association with electrophysiological evaluation. The project involves I'inserimento percutaneous catheter in the femoral vein and often in the internal jugular vein. The tips of the catheters are placed in specific locations within the heart. Through these catheters is administered electrical stimulation to the myocardium, in order to characterize the cardiac conduction and possible arrhythmias. Once studied the conduction system of the patient and diagnosed after the possible alteration of the rhythm, through a catheter ablation is administered heat to destroy the pathogen responsible for myocardial tissue initiation or maintenance of the arrhythmia. Success rates and complications of 'intervention vary and depend on the specific type of arrhythmia. The efficacy rates exceeding 88% for AV node reentrant tachycardia, atrioventricular reciprocating tachycardia to flutter and atrial exceed 86% for atrial tachycardia, and are between 60% and 80 % for atrial fibrillation. The complication rates are between 0% and 8% for supraventricular tachycardia and atrial flutter, and between 6% and 10% for atrial fibrillation. Complications associated with catheter ablation are attributed to exposure to radiation, the method of vascular access (eg, hematoma, cardiac perforation with tamponade), led to manipulation with the catheter (eg, cardiac perforation with tamponade (or thromboembolic events) and the impact of energy given to ablate (eg, atrioventricular block).



The introduction of catheters inside the heart, with or without the administration of ablative energy purposes will inevitably lead to a risk of perforation and cardiac tamponade. When recognized early, and the patient is on anticoagulant therapy (OAT) by systemic iatrogenic cardiac tamponade caused by perfection is a very serious complication that may jeopardize the patient's life.


 

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