Question Of The Day #27

question of the day
qod27
756.1 - palpitation - SOB

Which of the following is the most appropriate next step in management for this patient’s condition?

This patient has a narrow-complex, regular tachycardia that is causing the sensation of palpitations. The clinical history, rapid heart rate, and 12-lead EKG provide enough information to diagnose this patient with supraventricular tachycardia, also known as “SVT.” Supraventricular tachycardias refer to a broad range of arrhythmias, including sinus tachycardia, atrial fibrillation, atrial flutter, multifocal atrial tachycardia, and AV nodal re-entry tachycardia. This scenario specifically depicts an AV nodal re-entry tachycardia (AVNRT). AVNRT is a common type of SVT that can occur spontaneously or is triggered by sympathomimetic agents (i.e., cocaine, amphetamines), caffeine, alcohol, exercise, or beta-2 agonists using in asthma treatment (i.e., albuterol, salbutamol). AVNRTs are narrow-complex tachycardias with rates that range from 120-280bpm. P waves are typically absent in AVNRTs, but rarely they may be present as retrograde inverted P waves located immediately before or after the QRS complex. Symptoms experienced by the AVNRT patient may include pre-syncope, syncope, dizziness, palpitations, anxiety, or mild shortness of breath. Patients with AVNRTs are more likely to be young and female over male.

QRS complexes in AVNRTs are often narrow (<120msec), however, wide QRS complexes may be present in AVNRTs if there is a concurrent bundle branch block or Wolff-Parkinson White Syndrome. AVNRTs are often stable and do not require electric cardioversion. Signs that indicate instability and necessitate cardioversion are hypotension (SBP <90mmHg), altered mental status, or ischemic chest pain (more common if known history of ischemic heart disease). This patient lacks all of these signs and symptoms.

Treatment of AVNRT focuses on restoring the patient to normal sinus rhythm, which leads to resolution of symptoms. First-line medications for AVNRTs are short-acting AV nodal blocking agents, like adenosine (Choice A). Beta-blockers or calcium channel blockers act as second-line agents for patients who do not respond to adenosine. Metoprolol is a beta-blocker (Choice C) and Diltiazem is a calcium channel clocker (Choice D). Prior to any medications, vagal maneuvers should always be attempted first in a stable patient with AVNRT. The Valsalva maneuver (Choice B), or “bearing down,” is a commonly used vagal maneuver in the termination of AVNRTs. Other vagal maneuvers include the carotid massage or the Diving reflex (place bag of ice and water on face). Correct Answer: B

References

  • Brady W.J., & Glass III G.F. (2020). Cardiac rhythm disturbances. Tintinalli J.E., Ma O, Yealy D.M., Meckler G.D., Stapczynski J, Cline D.M., & Thomas S.H.(Eds.), Tintinalli’s Emergency Medicine: A Comprehensive Study Guide, 9e. McGraw-Hill. https://accessmedicine.mhmedical.com/content.aspx?bookid=2353&sectionid=218687685
  • Burns, E. (2020). Supraventricular Tachycardia (SVT). Life in the Fast Lane. Retrieved from https://litfl.com/supraventricular-tachycardia-svt-ecg-library/

Cite this article as: Joseph Ciano, USA, "Question Of The Day #27," in International Emergency Medicine Education Project, February 19, 2021, https://iem-student.org/2021/02/19/question-of-the-day-27/, date accessed: August 5, 2021

Question Of The Day #26

question of the day
qod26
38 - atrial fibrillation

Which of the following is the most appropriate next step in management for this patient’s condition?

This patient presents to the emergency department with palpitations, a narrow complex tachycardia (<120msec), and an irregularly irregular rhythm. A close look at this patient’s EKG reveals the absence of discrete P waves and QRS complexes that are spaced at varying distances from each other (most apparent in lead V6). These signs support a diagnosis of Atrial Fibrillation, or “AFib.” Atrial Fibrillation is an arrhythmia characterized by an irregularly irregular rhythm, the absence of P waves with a flat or undulating baseline, and narrow QRS complexes. Wide-QRS complexes may be present in AFib if there is a concurrent bundle branch block or Wolff-Parkinson White Syndrome. AFib is caused by the electric firing of multiple ectopic foci in the atria of the heart. This condition is triggered by a multitude of causes, including ischemic heart disease, valvular heart disease, dilated or hypertrophic cardiomyopathies (likely related to this patient’s congestive heart failure history), sepsis, hyperthyroidism, excess caffeine or alcohol intake, pulmonary embolism, and electrolyte abnormalities.

The main risk in AFib is the creation of thrombi in the atria as they fibrillate, resulting in emboli that travel to the brain and cause a stroke. The CHA2DS2VASc scoring system is used to risk stratify patients and determine if they require anticoagulation to prevent against thrombo-embolic phenomenon (i.e. stroke). This patient has a high CHA2DS2VASc score, so she would require anticoagulation. In addition to anticoagulation, A fib is treated with rate control (i.e. beta blockers or calcium channel blockers), rhythm control (i.e. anti-arrhythmic agents), or electrical cardioversion. Electrical cardioversion (choice A) is typically avoided when symptoms occur greater than 48 hours, since the risk of thrombo-emboli formation is higher in this scenario. An exception to this would be a patient with “unstable” AFib. Signs of instability in any tachyarrhythmia are hypotension, altered mental status, or ischemic chest pain. This patient lacks all of these signs and symptoms. Although this patient lacks signs of instability, this patient’s marked tachycardia should be addressed with medical treatment. General observation (Choice C) is not the best choice for this reason. Intravenous adenosine (Choice D) is the best choice for a patient with supraventricular tachycardia (SVT). This is a narrow-complex AV nodal re-entry tachycardia with rates that range from 120-280bpm. SVT also lacks discrete P waves. A key factor that differentiates A fib from SVT is that SVT has a regular rhythm, while AFib has an irregular rhythm. Intravenous metoprolol (Choice B) is the best treatment option listed in order to decrease the patient’s heart rate.

References

  • Brady W.J., & Glass III G.F. (2020). Cardiac rhythm disturbances. Tintinalli J.E., Ma O, Yealy D.M., Meckler G.D., Stapczynski J, Cline D.M., & Thomas S.H.(Eds.), Tintinalli’s Emergency Medicine: A Comprehensive Study Guide, 9e. McGraw-Hill. https://accessmedicine.mhmedical.com/content.aspx?bookid=2353&sectionid=218687685
  • Burns, E. (2020) Atrial Fibrillation. Life in The Fast Lane. Retrieved from https://litfl.com/atrial-fibrillation-ecg-library/

 

Cite this article as: Joseph Ciano, USA, "Question Of The Day #26," in International Emergency Medicine Education Project, February 12, 2021, https://iem-student.org/2021/02/12/question-of-the-day-26/, date accessed: August 5, 2021

Acute Management of Supraventricular Tachycardias

Acute management of SVT

The term “supraventricular tachycardia (SVT)” expresses all kinds of rhythms that meet two criteria: Firstly, the atrial rate must be faster than 100 beats per minute at rest. Secondly, the mechanism must involve tissue from the His bundle or above. Mechanism-wise, atrial fibrillation resembles SVTs. However, supraventricular tachycardia traditionally represents tachycardias apart from ventricular tachycardias (VTs) and atrial fibrillation (1,2).

Supraventricular tachycardias are frequent in the ED!

The SVT prevalence is 2.25 per 1000 persons. Women and adults older than 65 years have a higher risk of developing SVT! SVT-related symptoms include palpitations, fatigue, lightheadedness, chest discomfort, dyspnea, and altered consciousness.

How to manage supraventricular tachycardia?

In clinical practice, SVTs are likely to present as narrow regular complex tachycardias. Concomitant abduction abnormalities may cause SVTs to manifest as wide complex tachycardias or irregular rhythms. However, 80% of wide complex tachycardias are VTs. Most importantly, SVT drugs may be harmful to patients with VTs. Therefore, wide complex tachycardias should be treated as VT until proven otherwise (1,2).

The chart below summarizes acute management of regular narrow complex tachycardias:

Acute Management of Regular Narrow Tachycardias

References and Further Reading

  1. Brugada, J., Katritsis, D. G., Arbelo, E., Arribas, F., Bax, J. J., Blomström-Lundqvist, C., … & Gomez-Doblas, J. J. (2019). 2019 ESC Guidelines for the management of patients with supraventricular tachycardia: the Task Force for the management of patients with supraventricular tachycardia of the European Society of Cardiology (ESC). European Heart Journal, 00, 1-66.
  2. Page, R. L., Joglar, J. A., Caldwell, M. A., Calkins, H., Conti, J. B., Deal, B. J., … & Indik, J. H. (2016). 2015 ACC/AHA/HRS guideline for the management of adult patients with supraventricular tachycardia: a report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society. Journal of the American College of Cardiology67(13), e27-e115.