Sudden Racing Heart (SVT), Modified Valsalva Maneuver, and Arrhythmia Red Flags¶

When a healthy child, teenager, or adult feels their heart flip like a light switch and instantly race at \(160\text{ to }250\text{ beats per minute}\) with a rapid, regular machine-gun pulse in the neck, often triggered by bending over to tie a shoe, standing up quickly, dehydration, or stress, they are most likely experiencing Paroxysmal Supraventricular Tachycardia (PSVT / SVT), an electrical short-circuit loop centered on the atrioventricular (AV) node. While uncomplicated SVT in a stable patient can frequently be switched right back to normal rhythm at home in 60 seconds using the landmark REVERT Modified Postural Valsalva Maneuver (which more than doubles the success rate of old-fashioned straining by adding a 45-degree passive leg raise immediately after blowing), a sudden racing heart in an older adult, a patient with prior heart disease, or anyone with chest pain, shortness of breath, or fainting (syncope) can be Ventricular Tachycardia (VT) or Pre-Excited Atrial Fibrillation (Wolff-Parkinson-White [WPW] syndrome), which can degenerate into fatal cardiac arrest within minutes. Knowing how to check hemodynamic stability first, execute the exact 15-second blow + 45-second supine leg-lift Modified Valsalva Maneuver, safely perform infant facial ice-pack application, and never rub the neck arteries saves lives.

Do this now¶

1. Have the person sit or lie down immediately, stop all movement, and check for the 5 Unstable Arrhythmia Red Flags.
2. If the person has chest pain, trouble breathing, fainting/near-fainting, confusion, or a history of structural heart disease (prior heart attack, heart failure, or scarred heart muscle), call 911 / 112 / 999 right now (see all emergency numbers). In anyone with structural heart disease, assume a sudden racing heart is Ventricular Tachycardia (VT) until a 12-lead ECG proves otherwise.
3. Check the pulse at the wrist (radial artery) for 15 seconds and ask how the racing heartbeat STARTED:
4. Flip-of-a-switch instantaneous onset + rock-steady regular rhythm at \(160\text{ to }240\text{ bpm}\) + visible pounding in the base of the neck ("Frog Sign"): Classic Supraventricular Tachycardia (AVNRT or AVRT).
5. Gradual speed-up over several minutes + regular rhythm at \(110\text{ to }160\text{ bpm}\) during fever, pain, dehydration, or panic: Likely Sinus Tachycardia or a panic attack (vagal maneuvers will only briefly slow sinus tachycardia for 3 seconds and then it speeds right back up; treat the underlying fever, dehydration, or anxiety).
6. Chaotically irregular rhythm ("irregularly irregular" jumping pulse with no pattern at all): Likely Atrial Fibrillation (AFib) with Rapid Ventricular Response (RVR) (seek prompt medical evaluation for rate control and stroke prevention).
7. For a conscious, stable adult or older child with suspected SVT (and zero unstable red flags), perform the REVERT Modified Postural Valsalva Maneuver:
8. Phase 1 (Seated Semi-Recumbent 15-Second Strain): Sit the patient upright at a \(45\text{-degree}\) angle. Have them take a normal breath and blow forcefully for 15 full seconds into the tip of an empty \(10\text{ mL}\) plastic oral syringe trying to push the barrel plunger out (or pinch their nose shut and blow hard against closed lips as if trying to pop their ears for 15 full seconds).
9. Phase 2 (Immediate Flat Drop + 45-Degree Passive Leg Raise for 45 Seconds): At the exact end of the 15-second blow, tell the patient to stop blowing and breathe normally while a helper immediately lays the patient's upper body completely flat on their back (\(0\text{ degrees}\)) and lifts both of their legs straight up to a \(45\text{-degree}\) angle for 45 seconds.
10. Why Phase 2 is the secret: Dropping flat and lifting the legs dumps a wave of venous blood from the legs straight into the heart at the exact second the chest relaxes, creating a massive surge in vagus nerve pressure that snaps SVT back to normal rhythm in 43 percent of patients (compared to only 17 percent with standard sitting Valsalva).
11. For an infant or toddler with known or suspected SVT (heart rate \(220\text{ to }300\text{ bpm}\), pale/fussy, poor feeding): Apply a cloth-wrapped ice-water bag across the UPPER face (forehead, eyes, and bridge of nose) for 15 to 20 seconds while calling 911 / 112 / 999.
12. Never cover the baby's mouth or nostrils, and never press on the baby's eyeballs. Cold stimulation of the ophthalmic/maxillary trigeminal nerve branches across the forehead and bridge of the nose triggers the mammalian diving reflex, sending a vagal burst that stops pediatric SVT safely.
13. NEVER press on the eyeballs (ocular pressure) and NEVER allow a bystander to rub or massage the neck arteries (carotid sinus massage). Pressing on the eyeballs can detach the retina or damage the cornea, while rubbing the carotid artery in the neck can break loose an undiagnosed cholesterol plaque and cause an immediate paralyzing stroke.
14. If the racing heart does not stop after two Modified Valsalva attempts (or lasts more than 15 to 20 minutes), go to the Emergency Department. Call an ambulance; never drive yourself while in an active arrhythmia. If the patient has a cardiologist-prescribed "pill-in-the-pocket" medication (such as diltiazem, verapamil, or metoprolol), take it as directed and rest while awaiting medical care.

Emergency triage decision tree: Sudden racing heart (Tachyarrhythmia)¶

Use this clinical flowchart to triage a sudden fast heartbeat and determine when to perform the Modified Valsalva Maneuver versus immediate emergency resuscitation.

flowchart TD
    Start["Sudden Fast, Pounding, or Fluttering Heartbeat<br/>(Heart Rate > 130 to 250+ Beats Per Minute)"] --> UnstableCheck{"Check for the 5 UNSTABLE Red Flags:<br/>1. Chest pain, pressure, or tightness<br/>2. Shortness of breath / gasping<br/>3. Fainting (syncope), confusion, or severe dizziness<br/>4. Pale, clammy, cold skin (Shock)<br/>5. History of Heart Attack, Heart Failure, or VT"}

    UnstableCheck -->|"YES (ANY Red Flag Present)"| Call911["IMMEDIATE 911 / 112 / 999 EMERGENCY:<br/>1. Suspect Ventricular Tachycardia (VT), Pre-Excited AFib,<br/>   or Hemodynamically Unstable SVT<br/>2. Lay flat (or upright if breathless); ZERO walking<br/>3. Keep AED attached/ready; prepare for synchronized<br/>   cardioversion or defibrillation on EMS arrival"]

    UnstableCheck -->|"NO Red Flags (Patient Alert, Stable,<br/>No Chest Pain, Normal Breathing)"| PatternCheck{"Check Pulse Rhythm & Onset Pattern"}

    PatternCheck -->|"CHAOTICALLY IRREGULAR PULSE:<br/>Jumping rhythm with zero predictable pattern"| AFib["SUSPECT ATRIAL FIBRILLATION (AFib with RVR):<br/>1. Vagal maneuvers will NOT convert AFib to normal rhythm<br/>2. Seek same-day Emergency Room / Urgent Cardiology care<br/>   for 12-lead ECG, rate control, and stroke anticoagulation"]

    PatternCheck -->|"GRADUAL SPEED-UP (110 to 160 bpm):<br/>Started slowly with fever, dehydration, pain,<br/>caffeine/stimulants, or acute panic"| SinusTach["SUSPECT SINUS TACHYCARDIA:<br/>1. Treat underlying trigger (rehydrate with water/electrolytes,<br/>   treat fever/pain, perform slow 4-second box breathing)<br/>2. Seek medical care if resting HR stays > 120 bpm"]

    PatternCheck -->|"INSTANT 'LIGHT-SWITCH' ONSET:<br/>Rock-steady regular pulse at 160 to 250+ bpm<br/>+ Pounding in neck ('Frog Sign'):<br/>SUSPECT SUPRAVENTRICULAR TACHYCARDIA (SVT)"| AgeSplit{"Is the Patient an Adult / Older Child<br/>or an Infant / Toddler?"}

    AgeSplit -->|"Adult or Cooperative Child"| RevertValsalva["PERFORM REVERT MODIFIED VALSALVA MANEUVER:<br/>1. Sit at 45 degrees & blow hard into 10 mL syringe<br/>   (or against pinched nose/closed lips) for 15 SECONDS<br/>2. Immediately drop upper body FLAT (0 deg) and lift<br/>   both legs to 45 DEGREES for 45 SECONDS<br/>3. If still racing after 2 tries -> Call EMS / Go to ER<br/>   for IV Adenosine or Calcium Channel Blocker"]

    AgeSplit -->|"Infant or Young Toddler<br/>(HR 220 to 300 bpm)"| InfantIce["CALL 911 / 112 / 999 + INFANT DIVING REFLEX:<br/>Apply ice-water bag wrapped in thin cloth over<br/>FOREHEAD, EYES, & NASAL BRIDGE for 15-20 seconds<br/>(NEVER cover mouth or nostrils; NEVER press eyeballs)"]

Pathophysiology: How an SVT short-circuit works and how the Vagus Nerve breaks the loop¶

In a healthy heart at rest, every heartbeat begins at the natural pacemaker in the top right chamber (the sinoatrial [SA] node), travels across the top chambers (atria), pauses for \(0.1\text{ seconds}\) at a single electrical tollbooth in the center of the heart (the atrioventricular [AV] node), and then travels down into the bottom pumping chambers (ventricles) at \(60\text{ to }100\text{ beats per minute}\).

In Paroxysmal Supraventricular Tachycardia (PSVT / SVT), the person is born with a harmless microscopic extra electrical pathway, either two parallel tracks inside the AV node itself (AV Nodal Reentrant Tachycardia [AVNRT], accounting for 60% of SVT) or an extra microscopic muscle bridge connecting the atrium and ventricle (Atrioventricular Reciprocating Tachycardia [AVRT], accounting for 30% of SVT, including Wolff-Parkinson-White [WPW] syndrome): 1. How the "Light Switch" Flips On: One track conducts electricity fast but recovers slowly (fast pathway), while the second track conducts slowly but recovers fast (slow pathway). When an ordinary, harmless premature atrial contraction (skipped beat / PAC) fires at the exact millisecond when one track is resting and the other is open, the electrical impulse enters the open track and loops around in a circle at \(160\text{ to }250\text{ revolutions per minute}\) (a reentry circuit). 2. Why Patients Feel Pounding in Their Neck ("The Frog Sign"): In AVNRT, the top chambers (atria) and bottom chambers (ventricles) fire at the exact same millisecond. Because the tricuspid valve between the right atrium and right ventricle is slammed shut when the right atrium contracts, blood cannons backward up into the internal jugular veins of the neck, creating a visible, rhythmic pounding at the base of the neck (the "Frog Sign") that strongly distinguishes SVT from panic attacks or sinus tachycardia. 3. Why patients urinate heavily during or right after SVT: When the atria stretch against closed valves at \(200\text{ bpm}\), the heart muscle releases a hormone called Atrial Natriuretic Peptide (ANP), which tells the kidneys to dump large volumes of clear urine (tachycardia-induced polyuria) within 20 to 60 minutes. 4. How Vagal Maneuvers (and IV Adenosine) Break the Loop: Both the AVNRT loop and the AVRT loop must pass through the AV node on every single lap. The Vagus Nerve (Cranial Nerve X) wires directly into the AV node and releases acetylcholine, which briefly slows conduction through the AV node for 2 to 3 seconds. If you trigger a strong enough surge of vagus nerve activity to block just ONE single lap inside the AV node, the circular electrical racetrack hits a roadblock, extinguishes instantly, and the natural SA node pacemaker takes right back over at \(70\text{ to }90\text{ bpm}\).

Comprehensive comparison of the 5 acute fast-heart-rate conditions¶

Use this diagnostic table to differentiate benign sinus tachycardia and panic attacks from SVT, atrial fibrillation, and life-threatening ventricular tachycardia:

Step-by-step execution of the REVERT Modified Postural Valsalva Maneuver¶

For decades, standard first aid taught the "classic sitting Valsalva maneuver" (sitting upright and bearing down like having a bowel movement), which succeeded in fewer than 15 to 17 percent of emergency patients, forcing over 80 percent of patients to receive intravenous adenosine in the emergency room.

In 2015, the landmark REVERT Randomized Controlled Trial published in The Lancet (Appelboam et al.) revolutionized cardiology guidelines globally (AHA, ERC, ESC, and UK NICE/Resuscitation Council) by introducing the Modified Postural Valsalva Maneuver, which increased conversion rates from 17% up to 43% with zero drugs and zero adverse effects.

Why the Standard Valsalva Fails, and Why the 45-Degree Leg Lift Works¶

A Valsalva maneuver works in four physiological phases: - During Phase I and Phase II (the 15-second blow), high pressure inside the chest squeezes the vena cava shut, preventing venous blood from returning to the heart. Because less blood enters the heart, blood pressure drops slightly, and the body actually turns ON adrenaline (sympathetic tone) while turning OFF the vagus nerve. (The SVT almost NEVER stops while you are blowing.) - The magic happens in Phase III and Phase IV (5 to 20 seconds AFTER you stop blowing): When you let go of the strain and breathe normally, chest pressure drops to zero and the dammed-up venous blood rushes back into the heart. That sudden surge of blood stretches the pressure sensors (baroreceptors) in the aortic arch and carotid arteries, triggering a massive rebound Vagus Nerve braking reflex (Phase IV vagal overshoot) that stops the SVT. - Why Standard Sitting Valsalva Failed: If you stay sitting upright when you stop blowing, gravity traps the blood down in your legs, so only a tiny trickle returns to your heart (creating a weak Phase IV vagal reflex). - Why the REVERT Modification Triples Success: By having the patient blow while sitting up at \(45\text{ degrees}\), and then instantly dropping their torso flat (\(0\text{ degrees}\)) while lifting both legs to \(45\text{ degrees}\) at the exact second they stop blowing, gravity dumps \(300\text{ to }500\text{ milliliters}\) of pooled leg blood straight into the right atrium during Phase III, supercharging the Phase IV baroreceptor surge and stopping the SVT within 10 to 30 seconds.

Exact 4-Step Checklist to Perform the REVERT Modified Valsalva Maneuver¶

   PHASE 1: SEATED STRAIN (15 SECONDS)          PHASE 2: SUPINE + LEG LIFT (45 SECONDS)
        \                                                                   /  /
         \  45 deg   [Blow hard into 10 mL                                 /  /  45 deg
          \______     syringe for 15 sec]        \________________________/  /   Leg Lift
                 \                                 0 deg Flat Back

1. Position & Equipment Setup:
2. Seat the person upright at a \(45\text{-degree}\) semi-recumbent angle on a bed, couch, or carpeted floor where there is room behind their head to lay them completely flat in 1 second, and a helper (or footstool/wall) is ready at their feet to lift their legs.
3. How to generate the exact \(40\text{ mmHg}\) target blowing pressure:
   • Gold Standard (The \(10\text{ mL}\) Syringe Method): Give the person a clean, empty \(10\text{ mL}\) (\(2\text{ teaspoon}\)) plastic oral medicine syringe (the kind included in children's liquid ibuprofen/acetaminophen boxes). Have them put the small nozzle tip between their lips and blow hard enough to try to push the plunger backward. (Biomedical engineering studies prove that blowing against a \(10\text{ mL}\) syringe plunger generates almost exactly \(40\text{ mmHg}\) of intrathoracic pressure, the optimal pressure for the Valsalva reflex.)
   • No-Equipment Alternative: Have the person pinch their nostrils completely shut with one hand, close their lips tightly around their own thumb (like blowing into a trumpet that won't let any air escape), and blow hard with their chest and stomach muscles as if trying to pop their ears on an airplane or blow up a stiff new balloon.
4. Execute the 15-Second Continuous Strain:
5. Have the person take a normal breath in and blow steadily and forcefully for a full 15 seconds (count out loud: "One-one-thousand, two-one-thousand... up to fifteen").
6. Look for visible tightening of the neck and abdomen muscles and slight flushing of the face. Do not let air leak out of the nose or mouth.
7. Execute the Instant Postural Drop + 45-Degree Leg Lift (45 Seconds):
8. At the exact 15-second mark, tell the person: "Stop blowing, drop your hands, and breathe normally."
9. Simultaneously (within 1 to 2 seconds of stopping the blow), lay the person's head and torso completely flat on their back (\(0\text{ degrees}\), remove pillows) and lift both of their straight legs up to a \(45\text{-degree}\) angle, holding their ankles up (or resting them on a high stack of pillows/chair seat) for 45 full seconds.
10. Tell the person to stay completely relaxed and breathe normally while their legs are up. If the maneuver works, they will typically feel a single strong thump or brief 1-second pause between 10 and 25 seconds into the leg lift, followed by an immediate calm, slow heartbeat.
11. Return to Semi-Recumbent Position and Recheck the Pulse:
12. After 45 seconds with the legs elevated, lower the legs and bring the person back to a comfortable \(45\text{-degree}\) seated position for 1 minute, then check the wrist pulse.
13. If the heart is still racing at \(160\text{ to }240\text{ bpm}\) and the patient remains stable, wait 2 minutes and perform one second trial of the Modified Valsalva Maneuver. If two properly executed attempts do not convert the rhythm, call EMS or go to the emergency department.

Safe vs. Dangerous Vagal Maneuvers: What to Use and What to Avoid¶

Special Focus: Recognizing SVT in Infants and Young Children¶

In infants under 1 year of age, Supraventricular Tachycardia (SVT) is the single most common symptomatic arrhythmia, with heart rates roaring between \(220\text{ and }300\text{ beats per minute}\) (compared to a normal infant heart rate of \(110\text{ to }160\text{ bpm}\) at rest, or up to \(190\text{ bpm}\) when crying with a high fever). - Why Infant SVT Is Easy to Miss for 24 Hours: An infant cannot say, "My heart is racing." A baby in SVT at \(260\text{ bpm}\) can actually look surprisingly calm for the first 6 to 12 hours, until their heart muscle begins tiring out (tachycardia-induced heart failure). - Signs of SVT in an Infant: - Sudden refusal to breastfeed or take a bottle (or sweating and gasping while trying to suck). - Unusual fussiness, irritability, lethargy, or pale/mottled gray skin. - Fast, shallow breathing (tachypnea) and visible rapid fluttering of the chest wall or baby's clothing over the sternum. - A smartwatch, pulse oximeter, or stethoscope over the left chest counting a steady heartbeat over \(220\text{ beats per minute}\) that does not slow down when the baby calms down. - What to Do Immediately for an Infant in Suspected SVT: 1. Call 911 / 112 / 999 immediately (infants can decompensate into cardiogenic shock rapidly). 2. If the baby is conscious and breathing (or instructed by emergency dispatchers/pediatric cardiologist), fill a plastic bag with crushed ice and cold water, wrap it in a single thin damp layer of cloth, and place it gently across the upper half of the baby's face (covering the forehead, closed eyes, and bridge of the nose ONLY) for 15 seconds, leaving the nostrils and mouth 100 percent uncovered and visible. 3. Never hold an infant upside down and never press on the baby's eyes or rectal area.

What Happens in the Ambulance and Emergency Department: The "Adenosine Moment"¶

If the Modified Valsalva Maneuver does not stop SVT and you go to the emergency department, knowing what to expect removes fear: 1. 12-Lead ECG Recording: Before giving any medication, paramedics or ER nurses record a 12-lead ECG during the fast rhythm (and keep a continuous rhythm strip running during treatment) so a cardiologist can see the exact type of SVT and check for Wolff-Parkinson-White (WPW) delta waves once normal rhythm returns. 2. Intravenous Adenosine (\(6\text{ mg}\) then \(12\text{ mg}\) Rapid IV Push): - For regular narrow-complex SVT, clinicians place an IV in a large vein near the bend of the elbow (antecubital fossa) and inject adenosine followed immediately by a rapid \(20\text{ mL}\) saline flush. - What Adenosine Feels Like (Important Reassurance): Adenosine is a natural purine molecule with an ultra-short half-life of less than 10 seconds. When it hits the heart, it completely blocks the AV node for 3 to 6 seconds to reboot the heart's electrical system. For 5 to 10 seconds, the patient will feel a sudden heavy flushing warmth across their chest and face, a brief feeling of breathlessness, and a strange sensation that their heart paused, and then 10 seconds later the drug is 100 percent gone from the body and the heart is beating calmly at \(80\text{ bpm}\). - (Alternative gentler hospital option: Recent clinical trials show that intravenous calcium channel blockers like diltiazem or verapamil given as a slow 20-minute IV infusion convert SVT in >90% of stable patients without the 6-second chest-flushing pause of adenosine.) 3. Long-Term Cure (Catheter Ablation): After an episode of SVT, a referral to a cardiac electrophysiologist (EP) allows a minimally invasive outpatient procedure called catheter ablation, which permanently cures AVNRT and AVRT/WPW in 95 to 98 percent of patients so they never need lifelong daily heart medications.

Exact communication script for 911 / 112 / 999 and hospital triage¶

Use these clear clinical scripts when calling emergency dispatchers or arriving at hospital triage:

• For an Unstable Racing Heart (Chest Pain, Shortness of Breath, Fainting, or Prior Heart Disease):

  "I need an emergency ambulance with a cardiac monitor/defibrillator at [Exact Address]. The patient is a [Age]-year-old with a sudden racing heartbeat of approximately [Number] beats per minute accompanied by [chest pain / shortness of breath / dizziness / fainting / a history of prior heart attack or heart failure]. We suspect Ventricular Tachycardia or unstable arrhythmia and have the patient lying down at complete rest."

• For Stable Suspected SVT (When Going to the ER After Modified Valsalva):

  "I am at emergency triage with a [Age]-year-old patient who developed a sudden 'light-switch' onset regular tachycardia at approximately [180 to 220] beats per minute starting at [Time]. The patient is alert with no chest pain, and two trials of the REVERT Modified Postural Valsalva Maneuver did not convert the rhythm. We need an immediate 12-lead ECG while the arrhythmia is active and evaluation for SVT conversion."

• For an Infant with Suspected SVT (\(>220\text{ bpm}\)):

  "I need an emergency pediatric ambulance at [Exact Address]. My [Age]-month-old infant is pale, refusing feeds, and has a steady heart rate over [220 to 280] beats per minute with no fever. We suspect Infant Supraventricular Tachycardia (SVT)."

Frequently asked questions¶

Why does lifting my legs to 45 degrees right after blowing (the REVERT Modified Valsalva) work more than twice as well as just bearing down while sitting?¶

Blowing forcefully for 15 seconds builds high pressure in your chest that temporarily blocks blood from returning to your heart; the actual vagus nerve surge that stops SVT happens 5 to 20 seconds AFTER you stop blowing, when blood rushes back into the heart and stretches the aorta's pressure sensors. If you stay sitting upright when you stop blowing, gravity traps that blood down in your legs; by instantly laying your back flat and lifting your legs to 45 degrees the second you stop blowing, gravity pours a large wave of leg blood straight into your chest, triggering a powerful vagus nerve reflex that stops SVT in 43 percent of people.

How can I tell the difference between a panic attack (sinus tachycardia) and Supraventricular Tachycardia (SVT)?¶

While both cause a pounding heart, sweating, and a feeling of dread, SVT flips on instantaneously in a single heartbeat (often when bending over or moving suddenly) and beats at a rock-steady 160 to 250 beats per minute with visible pounding at the base of the neck ("the Frog Sign"), and then switches off instantaneously in a single beat. A panic attack (sinus tachycardia) ramps up gradually over several minutes, rarely exceeds 150 to 160 beats per minute in adults, and slows down gradually over 10 to 30 minutes as you calm down.

Why is it dangerous for a family member to rub my neck (carotid sinus massage) or press on my eyes to stop a racing heart?¶

Rubbing the carotid artery in the neck can crack open an undiagnosed cholesterol plaque inside the artery wall and shoot a blood clot directly into the brain, causing an immediate, permanently paralyzing stroke. Pressing on the eyeballs (the oculocardiac reflex) can tear or detach the retina and bruise the eye; neither maneuver should ever be performed outside of a hospital setting, especially when the safe REVERT Modified Valsalva Maneuver is far more effective.

Why do I have to urinate so much right after an episode of SVT or atrial fibrillation?¶

When the upper chambers of your heart (the atria) beat against closed heart valves at 180 to 220 beats per minute, the stretched atrial muscle walls release a natural hormone called Atrial Natriuretic Peptide (ANP) into your bloodstream. ANP signals your kidneys to rapidly flush out sodium and water to lower blood volume, causing a completely harmless flood of clear urination during or within 30 minutes after the racing heart episode.

Sources checked¶

• The Lancet (REVERT Randomized Controlled Trial, United Kingdom): Postural Modification to the Standard Valsalva Manoeuvre for Emergency Treatment of Supraventricular Tachycardias (REVERT): A Randomised Controlled Trial (Appelboam et al., The Lancet 2015; establishing the 15-second \(40\text{ mmHg}\) blow at \(45^\circ\) followed by 45-second supine \(0^\circ\) + \(45^\circ\) leg raise protocol).
• American Heart Association (AHA), American College of Cardiology (ACC), and Heart Rhythm Society (HRS, United States): Guideline for the Management of Adult Patients With Supraventricular Tachycardia and AHA Adult & Pediatric Advanced Life Support (ACLS / PALS) Tachyarrhythmia Algorithms.
• European Society of Cardiology (ESC) and European Resuscitation Council (ERC): ESC Guidelines for the Management of Patients with Supraventricular Tachycardia (Class I recommendation for the Modified Postural Valsalva Maneuver and avoidance of ocular pressure).
• Resuscitation Council UK and National Institute for Health and Care Excellence (NICE, United Kingdom): Peri-Arrest Tachycardia Guidelines and Pediatric SVT Facial Ice Application.

Related guides¶

• Implanted defibrillator (ICD) shock storm and pacemaker malfunction
• Acute myocarditis, pericarditis, and positional chest pain triage
• Heart attack recognition and first aid
• Fainting (syncope) first aid and cardiac red flags
• Panic attacks and hyperventilation grounding techniques