paroxysmal supraventricular tachycardia

Symptoms may include palpitations, feeling faint, sweating, shortness of breath, and chest pain.{{cite web|url=https://www.nhlbi.nih.gov/health/arrhythmias/symptoms|title=Arrhythmias - Symptoms|date=24 March 2022|access-date=7 November 2023|archive-date=7 November 2023|archive-url=https://web.archive.org/web/20231107142752/https://www.nhlbi.nih.gov/health/arrhythmias/symptoms|url-status=live}}{{cite web|url=https://www.nhlbi.nih.gov/health/conduction-disorders|title=Arrhythmias - Conduction disorders|date=24 March 2022|access-date=7 November 2023|archive-date=7 November 2023|archive-url=https://web.archive.org/web/20231107143115/https://www.nhlbi.nih.gov/health/conduction-disorders|url-status=live}} Episodes start and end suddenly.

• AV nodal re-entrant tachycardia (AVNRT) makes up 56% of cases
• Atrioventricular reentrant tachycardia (AVRT) makes up 27% of cases
• Wolff-Parkinson-White syndrome
• Paroxysmal atrial tachycardia makes up 17% of cases

Image:Supraventricular-extrasystole-leadII.png of electrocardiogram shows 3 rapid heartbeats, supraventricualar extrasistoles due to atrioventricular nodal reentry, shown as red, demonstrating unexplained onset and stop of the episode in paroxysmal supraventricular tachycardia among normal heart rhythm shown as blue]]Paroxysmal supraventricular tachycardia is a type of arrhythmia that originates in the atrioventricular (AV) junction. The most common underlying anatomical cause of PSVT is atrioventricular nodal reentry, which accounts for more than half of the cases.

The underlying anatomical causes of PSVT, specifically atrioventricular nodal reentry, involve the presence of two functionally distinct conduction pathways within the AV node and the formation of a reentrant circuit that sustains the tachycardia. These pathways within the AV node are known as the fast pathway and the slow pathway.{{cite journal |vauthors=Ganz LI, Friedman PL |title=Supraventricular tachycardia |journal=N Engl J Med |volume=332 |issue=3 |pages=162–73 |date=January 1995 |pmid=7800009 |doi=10.1056/NEJM199501193320307 |url=}}

The AV node is the structure that controls how electrical signals travel between the upper chambers (atria) and lower chambers (ventricles). During normal sinus rhythm, these signals pass through only one pathway, known as the fast pathway. The fast pathway conducts signals quickly but has a longer rest period before it can send another signal. However, in people with PSVT caused by atrioventricular nodal reentry, both the fast and the slow pathways are activated. The slow pathway conducts signals more slowly but has a shorter rest period.

In a healthy heart during normal sinus rhythm, only either the fast pathway or the slow pathway is used at any given moment for conducting electrical signals through the AV node, not both simultaneously.{{cite journal |vauthors=George SA, Faye NR, Murillo-Berlioz A, Lee KB, Trachiotis GD, Efimov IR |title=At the Atrioventricular Crossroads: Dual Pathway Electrophysiology in the Atrioventricular Node and its Underlying Heterogeneities |journal=Arrhythm Electrophysiol Rev |volume=6 |issue=4 |pages=179–185 |date=December 2017 |pmid=29326832 |pmc=5739891 |doi=10.15420/aer.2017.30.1 }}

During PSVT episodes, an irregular heartbeat is triggered by an early electrical signal from one of the atria. This premature signal enters both pathways simultaneously. It encounters no problem traveling along the slow pathway because its conduction speed matches up well with this specific arrhythmia type. However, it faces difficulty passing through effectively down the faster path since it takes slightly longer for that path to be ready following the conduction of a recent signal. At this point, if retrograde or backward flow overcomes the forward movement's pace in the fast pathway, then unwanted feedback further intensifies the rapid heartbeat until something intervenes to stop the episode. There is currently no solid understanding on what stops the episode in PSVT.

Treatment depends on the type of heart rhythm shown on an electrocardiogram test, and the stability of the patient's blood circulation.

If a patient has low blood pressure, difficulty breathing, chest pain, shock, or confusion, they are considered unstable and must have an electrocardiogram result checked to determine if the heart is beating normally. If this is not the case, cardioversion, which uses electricity to reset the heartbeat, should be performed urgently. If an electrocardiogram shows that the high heart rate is caused by something other than PSVT itself (such as a reduction in blood flow to the heart), injections of drugs called beta-blockers may help. The same medication can also be used if someone is found to be unstable due to inappropriate sinus tachycardia (a fast but unexplained normal heartbeat).{{cite book|pmid=29939521 |date=2023|title=Paroxysmal Supraventricular Tachycardia | vauthors = Hafeez Y, Quintanilla Rodriguez BS, Ahmed I, Grossman SA }}

AV nodal blocking can be achieved in at least three ways:

A number of physical maneuvers increase the resistance of the AV node to transmit impulses (AV nodal block), principally through activation of the parasympathetic nervous system, conducted to the heart by the vagus nerve. These manipulations are collectively referred to as vagal maneuvers.{{cite web | url=https://www.uptodate.com/contents/vagal-maneuvers/print | title=UpToDate }}

The Valsalva maneuver should be the first vagal maneuver tried{{cite web |url=http://www.bestbets.org/bets/bet.php?id=930 |title=BestBets: Comparing Valsalva manoeuvre with carotid sinus massage in adults with supraventricular tachycardia |url-status=live |archive-url=https://web.archive.org/web/20100616154713/http://bestbets.org/bets/bet.php?id=930 |archive-date=16 June 2010 }} and works by increasing intra-thoracic pressure and affecting baroreceptors (pressure sensors) within the arch of the aorta. It is carried out by asking the patient to hold his/her breath while trying to exhale forcibly as if straining during a bowel movement. Holding the nose and exhaling against the obstruction has a similar effect.{{cite web | title = Supraventricular Tachycardia | work = eMedicineHealth.com | date = 22 August 2005 | url = http://www.emedicinehealth.com/supraventricular_tachycardia/page7_em.htm | access-date = 28 November 2008 | url-status = live | archive-url = https://web.archive.org/web/20081216084703/http://www.emedicinehealth.com/supraventricular_tachycardia/page7_em.htm | archive-date = 16 December 2008 }}

Pressing down gently on the top of closed eyes may also bring heartbeat back to normal rhythm for some people with atrial or supraventricular tachycardia (SVT).{{cite web|title=Tachycardia {{!}} Fast Heart Rate|url=http://www.heart.org/HEARTORG/Conditions/Arrhythmia/AboutArrhythmia/Tachycardia_UCM_302018_Article.jsp|publisher=American Heart Association|access-date=19 April 2013|url-status=live|archive-url=https://web.archive.org/web/20130412034212/http://www.heart.org/HEARTORG/Conditions/Arrhythmia/AboutArrhythmia/Tachycardia_UCM_302018_Article.jsp|archive-date=12 April 2013}} This is known as the oculocardiac reflex. A 2023 review confirms the success of the Valsalva maneuver as a non-pharmaceutical intervention in PSVT.{{cite journal |vauthors=Tednes P, Marquardt S, Kuhrau S, Heagler K, Rech M |title=Keeping It "Current": A Review of Treatment Options for the Management of Supraventricular Tachycardia |journal=Ann Pharmacother |volume= 58|issue= 7|pages=715–727 |date=September 2023 |pmid=37743672 |doi=10.1177/10600280231199136 |s2cid=262429988 |url=}}

Image:Hr scan.jpg

Adenosine, an ultra-short-acting AV nodal blocking agent, is indicated if vagal maneuvers are not effective.{{cite web |url=http://www.bestbets.org/bets/bet.php?id=996 |title=Adenosine vs Verapamil (calcium channel blocker) in the acute treatment of supraventricular tachycardias |url-status=live |archive-url=https://web.archive.org/web/20100616155005/http://bestbets.org/bets/bet.php?id=996 |archive-date=16 June 2010 }} If unsuccessful or the PSVT recurs, calcium channel blockers, such as diltiazem or verapamil, are recommended. Adenosine may be safely used during pregnancy.Blomström-Lundqvist ET AL., MANAGEMENT OF PATIENTS WITH Supraventricular Arrhythmias. J Am Coll Cardiol 2003;42:1493–531 {{cite web |url=http://www.acc.org/qualityandscience/clinical/guidelines/arrhythmias/VI_special.htm |title=Supraventricular Arrhythmias Guideline Update |access-date=17 January 2010 |url-status=dead |archive-url=https://web.archive.org/web/20090310162847/http://www.acc.org/qualityandscience/clinical/guidelines/arrhythmias/VI_special.htm |archive-date=10 March 2009 }} Adenosine can be administered together with nondihydropyridine calcium channel blockers.

Calcium channel blockers such as verapamil and diltiazem have a longer half-life compared to adenosine. Although these blockers are safe when administered slowly, adenosine is considered safer and particularly useful in cases where an electrocardiogram does not provide clear information. Calcium channel blockers and verapamil have similar effectiveness. However, despite being safer overall, adenosine was associated with higher costs and an increased likelihood of arrhythmia recurrence compared to calcium channel blockers.{{cite journal |vauthors=Ahmad F, Abu Sneineh M, Patel RS, Rohit Reddy S, Llukmani A, Hashim A, Haddad DR, Gordon DK |title=In The Line of Treatment: A Systematic Review of Paroxysmal Supraventricular Tachycardia |journal=Cureus |volume=13 |issue=6 |pages=e15502 |date=June 2021 |pmid=34268033 |pmc=8261787 |doi=10.7759/cureus.15502 |doi-access=free |url=}}

SVT that does not involve the AV node may respond to other anti-arrhythmic drugs such as sotalol or amiodarone.{{cite web | url=https://www.acc.org/latest-in-cardiology/ten-points-to-remember/2019/09/10/12/36/2019-esc-guidelines-for-supraventricular-tachycardia | title=ESC Guidelines for Management of Supraventricular Tachycardia: Key Points | access-date=30 October 2024 | archive-date=14 June 2024 | archive-url=https://web.archive.org/web/20240614085655/https://www.acc.org/latest-in-cardiology/ten-points-to-remember/2019/09/10/12/36/2019-esc-guidelines-for-supraventricular-tachycardia | url-status=live }}

If the person is hemodynamically unstable or other treatments have not been effective, synchronized electrical cardioversion may be used. In children this is often done with a dose of 0.5 to 1 J/Kg.{{cite journal|title=Part 12: Pediatric Advanced Life Support: 2015 American Heart Association Guidelines Update for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care.|journal=Circulation|date=3 November 2015|volume=132|issue=18 Suppl 2|pages=S526–42|pmid=26473000|pmc=6191296|doi=10.1161/cir.0000000000000266 | vauthors = De Caen AR, Berg MD, Chameides L, Gooden CK, Hickey RW, Scott HF, Sutton RM, Tijssen JA, Topjian A, Schexnayder SM, Samson RA }}

Radiofrequency catheter ablation (RFCA) is a safe and effective treatment in both adults and children.{{cite journal |vauthors=Dung BT, Nhut NM, Son LC, An BG, Duc NM, Van Phuoc D |title=Radiofrequency catheter ablation for paroxysmal supraventricular tachycardia in children: Insights on its safety and efficacy from a lower middle-income country |journal=Int J Med Sci |volume=20 |issue=10 |pages=1293–1299 |date=2023 |pmid=37786440 |pmc=10542029 |doi=10.7150/ijms.86594 |url=}} RFCA is considered a minimally invasive procedure rather than surgery. It does not involve making large incisions or opening up the chest cavity. Instead, it is performed using thin catheters that are inserted through blood vessels and guided to the heart. The catheter delivers radiofrequency energy to specific areas of the heart to disrupt abnormal electrical pathways causing arrhythmias. While it may require mild sedation or local anesthesia, it doesn't typically involve extensive cutting or suturing of tissue associated with traditional surgical procedures.{{cite journal |vauthors=Haqqani HM, Roberts-Thomson KC |title=Radiofrequency catheter ablation for ventricular tachycardia |journal=Heart Lung Circ |volume=21 |issue=6–7 |pages=402–12 |date=June 2012 |pmid=22237136 |doi=10.1016/j.hlc.2011.10.015 |url=|doi-access=free }}

Over the decade of 2010s, there have been significant advancements in catheter ablation techniques for ventricular arrhythmias, including improved mapping methods like ultra-high density mapping and innovative energy sources like electroporation. New types of catheters, such as lattice and saline-enhanced radiofrequency catheters, provide more precise and longer-lasting tissue damage. Additionally, cardiac imaging technologies like MRI can help identify abnormal areas causing arrhythmias and evaluate the success of the ablation procedure.{{cite journal |vauthors=Marashly Q, Najjar SN, Hahn J, Rector GJ, Khawaja M, Chelu MG |title=Innovations in ventricular tachycardia ablation |journal=J Interv Card Electrophysiol |volume=66 |issue=6 |pages=1499–1518 |date=September 2023 |pmid=35879516 |doi=10.1007/s10840-022-01311-z |s2cid=251043386 |url=}}

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| ICD9 = {{ICD9|427.0}}

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