Paroxysmal supraventricular tachycardia

Paroxysmal supraventricular tachycardia

Supraventricular paroxysmal tachycardia (SPT) is a sudden sharp increase in cardiac activity (up to 140-250 per minute), resulting from the appearance of a highly active ectopic focus of automatism or circular reentrant excitation of re-entry, localized above the Huis bundle – in the atrioventricular junction, atrial myocardium,

    • sinoatrial node. Due to the fact that the P wave is often unbelievable to detect against the background of a pronounced tachycardia, the term supraventricular (supraventricular) paroxysmal tachycardia combines all kinds of atrial and atrioventricular reciprocal paroxysmal tachycardias that have many similarities (re-entry in the atrioventricular node, re -entry with Wolff-Parkinson-White syndrome, re-entry with hidden retrograde accessory pathways).

Mechanisms of occurrence – see Cardiac arrhythmias

    • Reciprocal (re-entry)
    • trigger
    • Focal.

Classification

    • By place of origin
    • Paroxysmal tachycardia from the atrioventricular junction
    • Atrial paroxysmal tachycardia
    • Sinus paroxysmal tachycardia (re-entry)
    • According to the mechanism of occurrence
    • Reciprocal form of NPT
    • Ectopic (focal) form of NTP (within 5% of proven cases of NTP)
    • Multifocal (multifocal) atrial paroxysmal tachycardia
    • According to the features of the flow
    • Paroxysmal form
    • Chronic (permanently relapsing) form of NTP
    • Continuously relapsing form, lasting for years without treatment, leading to arrhythmogenic dilated cardiomyopathy and circulatory failure.

Clinical picture

    • Rapid palpitations always start suddenly with a jolt, prick in the heart, stop or turn over
    • The attack is accompanied by severe anxiety, weakness, shortness of breath, chest pain or angina pectoris
    • Frequent and profuse urination
    • Sudden tachycardia is accompanied by a decrease in blood pressure
    • The duration of an NPT attack varies from a few seconds to several hours and days.
    • In 20% of patients, NPT attacks are interrupted spontaneously.

ECG identification

    • Heart rate 140-220 per minute
    • All types of NPT are characterized by narrow ventricular complexes (with the exception of cases of NTP with aberrant ventricular conduction)
    • Absence of P waves (merged with QRS complexes) or presence of positive or inverted P waves before or after tachycardia QRS complexes.

Treatment:

At the onset of NPT

    • Reflex methods (many of them are found and applied by the patient himself)
    • Head tilt
    • Pressure on the neck in the area of ​​the carotid sinus
    • An attempt to exhale with a closed glottis (Valsalva test)
    • An attempt to inhale with a closed glottis (Muller test)
    • Applying an ice collar to the neck
    • Face immersion in cold water (2°C) for 35 seconds (more effective in toddlers)
    • Pressure on the eyeballs
    • The introduction of vasopressor substances (mezaton) to stimulate baroreceptors with increased blood pressure
    • The effectiveness of methods of stimulation of the vagus nerve (massage or pressure in the area of ​​the carotid sinus, pressure on the eyeballs) increases after attempts to stop the attack with B-blockers.
    • Drug therapy
    • Verapamil (especially with polytopic atrial tachycardia) – 5 mg IV slowly under the control of blood pressure. In the absence of effect, the introduction is repeated after 5-10 minutes to a total dose of 15 mg. In 10%, it significantly reduces blood pressure. Diltiazem can be used instead of verapamil.
    • With inefficiency (or contraindications) of calcium channel blockers after their cancellation – B-blockers (effective in 50-60%). A side effect is arterial hypotension. With the introduction of verapamil, after the previous administration of B-blockers, the development of asystole or collapse is likely.
    • Novocain mid in a total dose of 1 g (effective in 80%).
    • Amiodarone IV .
    • Disopyramide IV .
    • With concomitant heart failure – cardiac glycosides (ineffective in the absence of signs of heart failure).
    • Electrical methods: electrical impulse therapy (see Cardioversion), cardiac stimulation.
    • Catheter destruction of the focus of increased activity.

To prevent recurrence of NTP

    • Amiodarone
    • Quinidine
    • B-blockers
    • Combination of quinidine with (5-blocker, quinidine with verapamil, cardiac glycosides with B-blocker. See also Paroxysmal atrial tachycardia. Paroxysmal tachycardia from the atrioventricular junction Abbreviation.

 

 

Leave a Comment

Your email address will not be published. Required fields are marked *