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,
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- 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
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- Reciprocal (re-entry)
- trigger
- Focal.
Classification
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- 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
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- 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
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- 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
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- 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
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- 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.