Supraventricular tachycardia is referred to as “supraventricular tachycardia”. Supraventricular tachycardia can be divided into two types: broad supraventricular tachycardia includes all kinds of tachycardia originating from sinus node, atrium, junctional area and bypass, such as atrioventricular nodal tachycardia due to double pathways, atrioventricular tachycardia due to preexcitation or bypass, atrial tachycardia, atrial flutter and atrial fibrillation. Supraventricular tachycardia in the narrow sense is mainly the atrioventricular nodal tachycardia due to double pathway and atrioventricular tachycardia due to preexcitation or bypass, and generally “supraventricular tachycardia” refers to these two types of supraventricular tachycardia in the narrow sense. If a patient with supraventricular tachycardia has preexcitation waves on the ECG under normal circumstances, this condition is also called “preexcitation syndrome”.
Atrioventricular node regurgitation tachycardia
Supraventricular tachycardia is caused by the presence of two or more conduction paths in the atrioventricular node, i.e., a fast path and a slow path or multiple slow paths, with electrical excitation forming a fold between the two conduction paths. AVNRT can be divided into three types: slow-fast, fast-slow, and slow-slow (Figure 1)
(a) Clinical manifestations: The heart rate may increase to 150-250 beats per minute for a few seconds or minutes, or hours to days. It can be abruptly terminated by treatment or by itself. Patients mainly feel panic, chest tightness, or in severe cases, dizziness, difficulty in breathing, and individual syncope may occur.
(B) ECG manifestations and diagnostic points: ECG is the main method to diagnose the disease, especially recording ECG in the case of panic is the most important basis to confirm the diagnosis. The general electrocardiogram performance is as follows (Figure 2)
1. heart rate of 135-230 bpm.
2, QRS wave pattern is supraventricular in tachycardia;
The Pˉ wave can be located before or after the QRS wave group, appearing as pseudo-q wave or pseudo-r wave; Pˉ wave can also be located in the QRS wave group, and no retrograde Pˉ wave can be seen during tachycardia.
(C) The main diseases that need to be distinguished
1.Atrial folding tachycardia
2.Atrial tachycardia
3, permanent junctional tachycardia
(D) Treatment.
1.Emergency treatment
(1) stimulation of the vagus nerve method: the patient can terminate the tachycardia by deep inspiration followed by breath-holding and then forceful whistling action (Valsalva method) or stimulation of the uvula (i.e., pharynx) with tongue depressor, etc. to produce nausea.
(2) Drug therapy: ① Isoptin 5mg diluted with saline and injected intravenously; ② Cetiran 0.4mg diluted with saline and injected intravenously; ③ AT P 10-20mg injected intravenously; ④ Cardioplegia 35-70mg diluted with saline and injected intravenously.
2.Prevention of recurrence
(1) Radiofrequency ablation: the preferred treatment method. The success rate is close to 100%, small trauma, safe, and few complications. In our hospital to pay a deposit of 40,000 (actually spend more than 30,000), need to be hospitalized for about 3-5 days, is the best treatment method, Monday or Wednesday morning to see my clinic on it. If you can’t get a number, we can add a number for you and arrange hospitalization and surgery for you.
(2) Drug treatment: For those who cannot perform radiofrequency ablation treatment due to various reasons, they can choose to take drug treatment. (1) Isoptin: 40-80mg orally, three times a day. (2) Cardioplegia: 100-200mg orally every 8 hours. Since supraventricular tachycardia is a paroxysmal attack, long-term medication is not recommended unless the attack is very frequent. Generally, the drug is discontinued 1-2 weeks after the onset of supraventricular tachycardia. If supraventricular tachycardia recurs after discontinuation, take the medication again.
Atrial folding tachycardia
The tachycardia formed by the normal atrioventricular conduction system and atrioventricular bypass is called atrioventricular reentrant tachycardia (AVRT). AV bypasses can be divided into occult bypasses and dominant bypasses. Occult bypasses do not show up on the normal ECG and their presence can only be demonstrated when AVRT occurs. A dominant bypass is manifested as a “preexcitation wave” on the ECG, and a patient with a preexcitation wave who experiences supraventricular tachycardia is also called a “preexcitation syndrome”.
(A) Types
1, cis-transmission atrioventricular folding tachycardia: refers to the excitation from the normal conduction system forward, by the bypass of the formation of retrograde tachycardia, generally narrow QRS wave group group tachycardia (Figure 3).
2, retrograde atrioventricular tachycardia: refers to the tachycardia formed by the anterior transmission of excitation from the bypass and retrograde transmission from the normal conduction system, usually wide QRS wave group tachycardia (Figure 4).
3, persistent junctional zone folding tachycardia: is a special kind of atrioventricular folding tachycardia, mostly occurs in children and adolescents, tachycardia often persistent episodes. The bypass is located in the posterior septum and generally has only retrograde conduction, with atrioventricular node-like decreasing conduction characteristics.
4. Tachycardia involving atrial bundle bypass (Mahaim fibers): Another specific type of atrial tachycardia, this bypass is mainly atrial bundle bypass fibers that originate in the right atrium, pass through the tricuspid annulus, and terminate in the distal right bundle branch of the right ventricle and/or its surrounding ventricular muscle. The bypass has atrioventricular node-like properties, with slow, decreasing conduction, and can only be transmitted anteriorly but not retrogradely.
(B) Electrocardiographic manifestations and diagnostic points
1. Electrocardiographic manifestations and diagnostic points of cis-transmission atrioventricular fold tachycardia.
(1) Normal QRS wave group, frequency 150-250 bpm.
(2) R Pˉ interval > 70ms, and R Pˉ interval often < Pˉ R interval.
(3) When tachycardia is accompanied by functional bundle branch block, if the R-R interval is more than 35ms longer than the normal QRS wave group, it suggests that the bypass is located on the same side of the bundle branch block.
2. Retrograde atrial folding tachycardia.
(1) Frequency 150-250 bpm.
(2) The QRS wave group is wide and deformed in a completely preexcited pattern, and the δ wave direction and QRS wave group morphology are similar to the preexcited ECG in sinus rhythm; however, in tachycardia, the excitation is completely transmitted through the bypass anteriorly, so the preexcitation is most fully expressed, and the preexcited wave and QRS wave group are more obvious and wider than in sinus rhythm.
(3) The PˉR interval is often very short, and the RPˉ interval > PˉR interval.
3. Persistent junctional zone folding tachycardia.
(1) Normal electrocardiogram in sinus rhythm.
(2) Tachycardia frequency of 100-200 beats/min.
(3) Tachycardia with narrow QRS waves, alternating with short paroxysms of sinus rhythm, and recurrent episodes.
(4) Tachycardia with negative retrograde Pˉ waves in leads II, III, aVF, V4-V6.
(5) RPˉ interval > Pˉ R interval.
4. Tachycardia involving atrial bundle bypass (Mahaim fibers).
(1) Frequency-dependent left bundle branch block pattern in sinus rhythm: rS pattern of QRS waves in V1 leads, left-skewed electrical axis, and slow migration in the anterior chest leads.
(2) Normal or prolonged PR interval.
(3) Wide QRS tachycardia with left bundle branch block pattern during tachycardia.
(C) The main diseases to be differentiated
(1) Atrioventricular node folding tachycardia.
2, atrial tachycardia.
3.Ventricular tachycardia.
(D) Treatment
1.Emergency treatment
(1) Stimulation of the vagus nerve method: patients can terminate tachycardia by deep inspiration followed by breath-holding and then forceful whistling action (Valsalva method) or stimulation of the uvula (i.e., pharynx) with tongue depressor, etc. to produce nausea.
(2) Drug therapy: cis-transmission atrial tachycardia can be treated with isoptin 5mg diluted with saline and injected intravenously or with cardioplegia 35-70mg diluted with saline and injected intravenously. Isoptin, Cediran or ATP are contraindicated in preexcited or retrograde atrioventricular tachycardia.
Only use cardioplegia 35-70mg diluted with saline and injected intravenously. Pre-excited patients with atrial fibrillation can use amiodarone intravenously or direct current defibrillation.
2.Prevent recurrence
(1) Radiofrequency ablation: the preferred treatment method. The success rate is close to 100%, small trauma, safe, and few complications.
(2) Drug therapy: For those who cannot perform radiofrequency ablation treatment for various reasons, drug therapy can be chosen. In cases of supraventricular tachycardia due to occult bypass, ① Isoptin: 40-80mg orally (prohibited for those with pre-excitation), three times daily. (2) Cardioplegia: 100-200 mg orally every 8 hours. Since supraventricular tachycardia is a paroxysmal attack, it is not recommended to take the drug for a long time unless the attack is very frequent. Generally, the drug is taken for 1-2 weeks after the onset of supraventricular tachycardia and then tried to stop.