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SVT on the ECG!

Technically speaking, SVT includes any arrhythmia that originates above the Bundle of His - this would include etiologies such as afib and flutter. However, from an ER perspective, when we use the term SVT, we are not talking about afib or flutter. We are usually using this term synonymously with AVNRT (AV nodal reentrant tachycardia) though there are certainly other types of “SVT”.

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 Supraventricular tachycardia (SVT)

AF: usually ~120s-180s, but may be faster. AFlutter: usually 280-320 with 2:1 conduction yielding a ventricular rate of ~~140-160 b/m. AVNRT (orthodromic): ~140-220 b/m. AVRT (orthodromic): ~150-250 b/m. FAT: ~100-180 b/m (but can range up to 250 b/m). Junctional tachycardia: usually ~100-140 b/m (but may increase to 220). Sinus tach: up to (220-age). Sinus node reentry tachycardia: ~100-150 b/m. Ventricular tachycardia: usually above ~120 b/m.

 Vagal Maneuvers with Supraventricular Tachycardia

Multiple variations of VM have been used in medicine. These include... Bearing Down: Medically referred to as the Valsalva Maneuver, this technique is one of the most common ways to stimulate the vagus nerve. The patient is instructed to bear down as if they were having a bowel movement. In effect, the patient is expiring against a closed glottis. An alternative way to perform a Valsalva Maneuver is to tell the patient to blow through an occluded straw or barrel of a 10 ml syringe for 15-20 seconds. These maneuvers increase intrathoracic pressure and stimulate the vagus nerve.

Articles of Interest

How can I self help with supraventricular tachycardia (SVT)?

An SVT is caused generally in 3 ways: A part or parts of the atria (not the SA node) gives off impulses which can then pass through the heart, overriding the SA node and causing the heart to beat faster (atrial tachycardia) An extra bit of wiring exists within the AV node allowing a short circuit and fast heart rhythm (AVNRT) There is an extra bit of wiring present in the heart between the atria and ventricles or within the atria. This can lead to a short circuit, causing a fast heart rhythm (AVRT) or Wolff-Parkinson-White (WPW) syndrome

Lifestyle Changes to Help Manage Arrhythmia

Examples of vagal manoeuvres: Valsalva manoeuvres – forcing an outward breath against closed airways, Carotid sinus massage – massaging the carotid artery for five to ten seconds, Performing a handstand for 30 seconds, if you can, Dunking or splashing your face with ice-cold water, Straining while holding your breath.

Supraventricular Tachycardia (SVT): Strategies for Diagnosis, Risk Stratification, and Management in the Emergency

Distinguishing physiologic sinus tachycardia from other types of pathologic SVTs can be difficult. This distinction is important in the clinical management of SVT because the therapeutic approaches differ widely. The distinction between physiologic and pathologic tachycardias is best made by careful examination of the patient’s vital signs, the history and physical exam, and careful analysis of the electrocardiogram (ECG). Although physiologic tachycardia is a type of SVT, it may be a result of states such as sepsis, dehydration, or hemorrhagic shock.

Supraventricular Tachydysrhythmias in the Emergency Department

Diagnosing and treating supraventricular tachycardias is routine in emergency medicine, and new strategies can improve efficiency and outcomes. This review provides an overview of supraventricular tachycardias, their pathophysiology, differential diagnosis, and electrocardiographic features. Clinical evidence guiding contemporary practice is determined largely by multiple observational studies, with few randomized controlled trials. Current prehospital and emergency department management strategies beyond the use of adenosine and calcium channel blockers are addressed.

SVT in the Field: Revisiting Adenosine and Diltiazem as First-Line Agents

The American Heart Association (AHA) defines SVT as “an umbrella term used to describe tachycardias (in rates excess over 100), the mechanism of which involves tissue from the His bundle or above”. The most encountered type is AVNRT, a reentrant tachycardia mediated by an accessory pathway. Treatment for SVT patients who are deemed stable are targeted at slowing conduction through the atrioventricular node (AV node). This can be done via a Valsalva maneuver in attempt to induce a vagal response. Medical treatment was classically three rounds of Adenosine, followed by Diltiazem if refractory.

The Valsalva Maneuver: What it is and how to perform it

From popping plugged-up ears to settling an irregular heartbeat, the Valsalva Maneuver is an effective way to treat some minor medical issues. It’s a series of breathing actions that you can perform on your own—no invasive instruments or medications needed.

When I was 11, out of nowhere I started to experience tachycardia,

Even once the SVT episodes have started, it may be difficult to diagnose SVT, making it a long and drawn out process before reaching the diagnosis.

“Home remedies” for SVT - Pediatrics

There are a few ways a parent or caregiver can provide SVT treatment at home, and these involve stimulating the vagus nerve to return the heart rate back to normal. If your child looks ill during SVT or SVT doesn’t stop with these methods, your child will need care from a professional...

Resources

Cardiogram

The Cardiogram App transforms your everyday wearable into a clinically-validated heart health monitor.

Life in the Fastlane

It is often used synonymously with AV nodal re-entry tachycardia (AVNRT), a form of SVT.

StatPearls

Supraventricular tachycardia (SVT) is a dysrhythmia originating at or above the atrioventricular (AV) node and is defined by a narrow complex (QRS < 120 milliseconds) at a rate > 100 beats per minute (bpm). Atrioventricular nodal reentrant tachycardia (AVNRT), also known as paroxysmal SVT, is defined as intermittent SVT without provoking factors, and typically presents with a ventricular rhythm of 160 bpm.