Question Of The Day #29

question of the day
qod29
842 - Wide QRS complex tachycardia

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

This patient presents to the emergency department with seven days of severe vomiting, diarrhea, tachycardia, and borderline hypotension. The clinician should be concerned about dehydration and potential electrolyte derangements induced by the vomiting and diarrhea. Certain electrolyte derangements can put a patient at risk for cardiac dysrhythmias, so ordering a 12-lead EKG is an important step in evaluating any patient with a potential electrolyte disturbance. Dangerous electrolyte disturbances that can predispose a patient to cardiac dysrhythmias include hyperkalemia, hypokalemia, hypomagnesemia, and hypocalcemia. Signs of hyperkalemia on the EKG include peaked T waves, absent or flattened P waves, widened QRS complexes, or a sine wave morphology. Low potassium, magnesium, and calcium can all prolong the QT interval and predispose the patient to polymorphic ventricular tachycardia (Torsades de Pointes). Hypokalemia on EKG may also be associated with a U wave, which is an upward wave that follows the T wave.

This patient’s 12-lead EKG shows a wide-complex tachycardia with QRS complex “twisting” around the isoelectric line and varying QRS amplitudes. These EKG signs, along with the inferred history of severe electrolyte abnormalities, support a diagnosis of Torsades de Pointes (TdP). Another risk factor for TdP is a history of congenital prolonged QT syndromes. Similar to monomorphic ventricular tachycardia, TdP should always be treated with electrical cardioversion if there are any signs of instability (i.e., altered mental status, SBP <90mmHg). A pulseless patient with TdP always necessitates unsynchronized cardioversion, also known as defibrillation. This patient may have briefly syncopized or potentially underwent cardiac arrest. Intravenous Amiodarone (Choice A) and Procainamide (Choice B) are contraindicated in TdP as both of these agents can further prolong the QT interval. These agents can be used in a stable patient with monomorphic ventricular tachycardia. Intravenous Ciprofloxacin (Choice C) is a quinolone antibiotic that is useful for treating infections from gram-negative bacteria. This may be beneficial for this patient, especially if there is a concern for bacterial gastroenteritis. However, quinolone antibiotics also can prolong the QT interval, and this medication will not acutely stabilize this patient. Intravenous Magnesium Sulfate (Choice D) shortens the QT interval and is the preferred therapy for a TdP patient with a pulse. Correct Answer: D

References

Cite this article as: Joseph Ciano, USA, "Question Of The Day #29," in International Emergency Medicine Education Project, March 5, 2021, https://iem-student.org/2021/03/05/question-of-the-day-29/, date accessed: August 5, 2021

Question Of The Day #28

question of the day
qod28

EKG#1

710 - hyperkalemia

EKG#2

855 - bradycardia

Which of the following is the most likely underlying cause for this patient’s condition?

This patient presents to the emergency department with vague and nonspecific symptoms of nausea, fatigue, and palpitations. The initial EKG (EKG #1) demonstrates a wide-complex tachycardia (QRS >120msec) with a regular rhythm. The differential diagnosis for wide-complex tachyarrhythmias include ventricular tachycardia (monomorphic ventricular tachycardia), torsades de pointes (polymorphic ventricular tachycardia), coarse ventricular fibrillation, supraventricular tachycardias with aberrancy (i.e. underlying Wolf Parkinson White Syndrome or Ventricular Bundle Branch Block), electrolyte abnormalities (i.e., Hyperkalemia), and from medications (i.e., Na channel blocking agents). If the history is unclear or the patient shows signs of instability, Ventricular tachycardia should always be the assumed tachyarrhythmia. This is managed with electrical cardioversion or with medications (i.e., amiodarone, procainamide, lidocaine), depending on the patient’s symptoms and hemodynamic stability.

The prior EKG for the patient (EKG #2) is helpful in showing that the patient does not have a wide QRS complex at baseline. There also are no EKG signs of Wolf Parkinson White Syndrome (Choice B) on EKG #2, making this choice incorrect. Signs of this cardiac pre-excitation syndrome on EKG include a shortened PR interval and a delta wave (slurred upstroke at the beginning of the QRS complex). Anxiety (Choice D) can cause sinus tachycardia and be a symptom associated with any arrhythmia, but it is not the underlying cause for this patient’s bizarre wide-complex tachydysrhythmia. On a closer look, the patient’s EKG (EKG #1) demonstrates tall, peaked T waves in the precordial leads. This supports a diagnosis of hyperkalemia. Other signs of hyperkalemia on EKG include flattened or absent P waves, widened QRS complexes, or a sine wave morphology. A common underlying cause of hyperkalemia is renal disease (Choice C). Ischemic heart disease (Choice A) is a common underlying cause for ventricular tachycardia. Ventricular tachycardia is less likely in this case given the presence of peaked T waves and the lack of fusion beats, capture beats, or signs of AV dissociation on the 12-lead EKG. Correct Answer: C 

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). Ventricular Tachycardia – Monomorphic VT. Life in The Fast Lane. Retrieved from https://litfl.com/ventricular-tachycardia-monomorphic-ecg-library/

Cite this article as: Joseph Ciano, USA, "Question Of The Day #28," in International Emergency Medicine Education Project, February 26, 2021, https://iem-student.org/2021/02/26/question-of-the-day-28/, date accessed: August 5, 2021

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

Question Of The Day #25

question of the day
qod25
835 - 3rd degree heart block

Which of the following is the most likely diagnosis of this patient’s condition?

This patient has marked bradycardia on exam with a borderline low blood pressure. These vital sign abnormalities are likely the cause of the patient’s dizziness. Bradycardia is defined as any heart rate under 60 beats/min. The most common cause of bradycardia is sinus bradycardia (Choice A). Other types of bradycardia include conduction blocks (i.e. type 2 or type 3 AV blocks), junctional rhythms (lack of P waves with slow SA nodal conduction), idioventricular rhythms (wide QRS complex rhythms that originate from the ventricles, not atria), or low atrial fibrillation or atrial flutter. About 80% of all bradycardias are caused by factors external to the cardiac conduction system, such as hypoxia, drug effects (i.e., beta block or calcium channel blocker use or overdose), or acute coronary syndromes.

ecg qod25Sinus bradycardia (Choice A) occurs when the electrical impulse originates from the SA node in the atria. Signs of sinus bradycardia on EKG are the presence of a P wave prior to every QRS complex. This EKG shows P waves prior to each QRS complex, but there are extra P waves that are not followed by QRS complexes. Some P waves are “buried” within QRS complexes or within T waves. The EKG below marks each P wave with a red line and each QRS complex with a blue line.

 

First-degree AV Block (Choice B) is a benign arrhythmia characterized by a prolonged PR interval. This patient’s EKG has variable PR intervals (some prolonged, some normal). This is a result of a more severe AV conduction block. Second-Degree AV Blocks are divided into Mobitz type I and Mobitz Type II. Mobitz type I, also known as Wenckebach, is characterized by a progressive lengthening PR interval followed by a dropped QRS complex. This can be remembered by the phrase, “longer, longer, longer, drop.” Wenckebach is a benign arrhythmia that does not typically require any treatment. Mobitz type II (Choice C) is characterized by a normal PR interval with random intermittent dropping of QRS complexes. This patient’s EKG has consistent spacing between each QRS complex (blue lines) and consistent spacing between each P wave (red lines). However, the P waves and QRS complexes are not associated with each other. This phenomenon is known as AV dissociation. These EKG changes are signs of a complete heart block, also known as Third-Degree AV Block (Choice D). Both Second-Degree AV block- Mobitz type II (Choice C) and Third-Degree AV Block (Choice D) are more serious conduction blocks that require cardiac pacemakers. Correct Answer: D

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
  • Nickson, C. (2020). Heart Block and Conduction Abnormalities. Life in the Fast Lane. Retrieved from https://litfl.com/heart-block-and-conduction-abnormalities/

 

Cite this article as: Joseph Ciano, USA, "Question Of The Day #25," in International Emergency Medicine Education Project, February 5, 2021, https://iem-student.org/2021/02/05/question-of-the-day-25/, date accessed: August 5, 2021