Dysrhythmias Flashcards
- What property of cardiac cells prevents immediate re-excitation following depolarization?
A. Automaticity
B. Refractoriness
C. Conductivity
D. Excitability
o Answer: B
o Rationale: Refractoriness (absolute and relative) prevents immediate re-excitation, protecting the heart from arrhythmias.
- Which of the following best describes reentry as a mechanism for dysrhythmias?
A. Spontaneous depolarization of normally quiescent cells
B. A short circuit in which an impulse repeatedly travels along a circuitous pathway
C. Blockage of the AV node by high vagal tone
D. Failure of the SA node to generate impulses
o Answer: B
o Rationale: Reentry involves a circulating impulse reactivating
- Which of the following is an initial nonpharmacologic intervention for stable SVT?
A. Synchronized cardioversion
B. Intravenous adenosine
C. Vagal maneuvers (e.g., Valsalva maneuver)
D. Immediate defibrillation
o Answer: C
o Rationale: Vagal maneuvers are first-line for stable SVT, as they can slow AV nodal conduction and terminate the arrhythmia.
- Enhanced automaticity in cardiac tissue can result from which of the following?
A. Increased vagal tone
B. Ischemia or electrolyte imbalances
C. Prolonged refractory period
D. Beta-blocker therapy
o Answer: B
o Rationale: Ischemia, electrolyte disturbances, and other injuries can increase automaticity and predispose to dysrhythmias
- What is the typical EKG characteristic of supraventricular tachycardia (SVT)?
A. Wide QRS complexes with ST depression
B. Narrow QRS complexes with a regular rhythm and a rate often above 150 bpm
C. Irregularly irregular rhythm with no discernible P waves
D. Bradycardia with a prolonged PR interval
o Answer: B
o Rationale: SVT typically presents as a narrow complex, regular tachycardia with rates usually above 150 bpm.
- Which dysrhythmia is characterized by an “irregularly irregular” rhythm with absent P waves on the EKG?
- A. Atrial flutter
B. Atrial fibrillation
C. Paroxysmal SVT
D. Junctional tachycardia
o Answer: B
o Rationale: Atrial fibrillation is typically irregularly irregular, with no distinct P waves.
- Adenosine is used in the management of SVT primarily because it: A. Prolongs the refractory period of the AV node
B. Increases myocardial contractility
C. Blocks sympathetic outflow
D. Acts as a calcium channel blocker
o Answer: A
o Rationale: Adenosine temporarily blocks conduction through the AV node, interrupting reentrant circuits in SVT.
- In unstable patients with SVT (e.g., hypotension, altered mental status), the next step in management is: A. Continue vagal maneuvers
B. Administer adenosine
C. Synchronized cardioversion
D. Initiate beta-blocker therapy
o Answer: C
o Rationale: Unstable SVT requires immediate synchronized cardioversion to restore a normal rhythm
- Which treatment is commonly used for rate control in patients with atrial fibrillation? A. Adenosine
B. Calcium channel blockers (e.g., diltiazem)
C. Procainamide
D. Amiodarone
.
o Answer: B
o Rationale: Calcium channel blockers, along with beta blockers, are used to control ventricular rate in atrial fibrillation
- A patient presents with a narrow complex tachycardia at 170 bpm, stable blood pressure, and no signs of heart failure. The initial management should be: A. Intravenous beta-blockers
B. Vagal maneuvers
C. Synchronized cardioversion
D. Implantable cardioverter-defibrillator (ICD) placement
o Answer: B
o Rationale: Stable narrow complex tachycardia is first managed with vagal maneuvers before pharmacologic intervention
- Atrial flutter typically shows a “saw-tooth” pattern on the EKG. Which of the following interventions can be used to slow ventricular response in atrial flutter? A. Vagal maneuvers
B. Beta blockers
C. Calcium channel blockers
D. All of the above
o Answer: D
o Rationale: Vagal maneuvers, beta blockers, and calcium channel blockers can all be used to slow AV conduction in atrial flutter.
- For patients with atrial fibrillation, what is a common “harm” if anticoagulation is not properly managed? A. Systemic embolism
B. Myocardial infarction
C. Bradycardia
D. Hypotension
o Answer: A
o Rationale: Inadequate anticoagulation in atrial fibrillation increases the risk of embolic events such as stroke
- Which of the following is a potential complication (“what will kill your patient”) of untreated atrial fibrillation? A. Pulmonary embolism
B. Thromboembolic stroke
C. Ventricular fibrillation
D. Bradycardia
o Answer: B
o Rationale: Atrial fibrillation increases the risk of thrombus formation in the atria, leading to embolic stroke.
- Which ventricular dysrhythmia is characterized by a uniform, wide QRS complex and may be treated with antiarrhythmic drugs if the patient is hemodynamically stable? A. Ventricular fibrillation
B. Sustained monomorphic ventricular tachycardia
C. Torsades de pointes
D. Sinus tachycardia
o Answer: B
o Rationale: Sustained monomorphic VT has a uniform QRS morphology and may be managed with drugs like amiodarone if the patient is stable.
- If a patient with sustained monomorphic ventricular tachycardia is hemodynamically unstable, the appropriate intervention is: A. Intravenous amiodarone
B. Synchronized cardioversion
C. Vagal maneuvers
D. Observation
o Answer: B
o Rationale: Unstable VT requires immediate synchronized cardioversion to restore an effective rhythm.
- Torsades de pointes is a form of polymorphic VT often associated with:
- A. Short QT interval
B. Prolonged QT interval
C. Atrial flutter
D. First-degree AV block
o Answer: B
o Rationale: Torsades is typically seen in the setting of a prolonged QT interval, which predisposes to this “twisting” ventricular tachycardia
- Which medication is considered first-line in treating stable monomorphic VT? A. Adenosine
B. Amiodarone
C. Lidocaine
D. Beta blockers
.
o Answer: B
o Rationale: Amiodarone is commonly used for stable monomorphic VT due to its broad-spectrum antiarrhythmic effects
- What is the initial treatment for torsades de pointes in a hemodynamically stable patient?
- A. Intravenous magnesium sulfate
B. Synchronized cardioversion
C. High-dose beta blockers
D. Immediate defibrillation
o Answer: A
o Rationale: IV magnesium sulfate is the first-line treatment for torsades de pointes, even if the serum magnesium level is normal.
- In pulseless ventricular tachycardia or ventricular fibrillation, what is the first step in management? A. Administration of amiodarone
B. Immediate unsynchronized defibrillation
C. Vagal maneuvers
D. Synchronized cardioversion
o Answer: B
o Rationale: For shockable rhythms (pulseless VT/VF), immediate defibrillation is indicated per ACLS guidelines.
- What distinguishes pulseless electrical activity (PEA) from ventricular fibrillation on the EKG? A. PEA shows organized electrical activity without a mechanical pulse
B. PEA is characterized by chaotic, disorganized electrical activity
C. PEA always presents with a narrow QRS complex
D. PEA demonstrates a “saw-tooth” pattern
o Answer: A
o Rationale: PEA has organized electrical activity but no effective mechanical heart action; in contrast, VF is disorganized.
Which reversible causes of PEA and asystole should be assessed during cardiac arrest? A. Hypovolemia, hypoxia, hyperkalemia, and hypothermia
B. Only myocardial infarction
C. Only pulmonary embolism
D. Only drug overdose
Answer: A
Rationale: The “Hs and Ts” (hypovolemia, hypoxia, hyperkalemia, hypothermia, etc.) must be evaluated as reversible causes in PEA/asystole
During synchronized cardioversion for dysrhythmias, why is synchronization important? A. It minimizes the risk of inducing ventricular fibrillation
B. It increases the energy required for shock delivery
C. It enhances the speed of defibrillation
D. It is only used for bradyarrhythmias
Answer: A
Rationale: Synchronized cardioversion times the shock to avoid the vulnerable T-wave, reducing the risk of inducing VF.
Which of the following is a common cause (“what is really common”) of ventricular dysrhythmias? A. Acute myocardial ischemia
B. Gastrointestinal bleeding
C. Migraine headaches
D. Hypothyroidism
Answer: A
Rationale: Acute myocardial ischemia is a frequent precipitant of life-threatening ventricular dysrhythmia
When administering adenosine for SVT, why must the drug be given rapidly? A. Because it has a long half-life
B. Because it is rapidly metabolized
C. To prevent hypotension
D. To avoid inducing bradycardia
Answer: B
Rationale: Adenosine has a very short half-life, so rapid administration is necessary to achieve effective AV node blockade
Which factor could “harm your patient” if misinterpreted during the treatment of dysrhythmias? A. Using adenosine in a patient with atrial fibrillation with rapid ventricular response
B. Correctly identifying the rhythm before treatment
C. Monitoring electrolyte levels
D. Performing vagal maneuvers in stable patients
Answer: A
Rationale: Adenosine is contraindicated in atrial fibrillation as it may worsen the rhythm; misinterpretation can lead to harmful interventions
When administering adenosine for SVT, why must the drug be given rapidly?
A. Because it has a long half-life
B. Because it is rapidly metabolized
C. To prevent hypotension
D. To avoid inducing bradycardia
Answer: B
Rationale: Adenosine has a very short half-life, so rapid administration is necessary to achieve effective AV node blockade
Which factor could “harm your patient” if misinterpreted during the treatment of dysrhythmias? A. Using adenosine in a patient with atrial fibrillation with rapid ventricular response
B. Correctly identifying the rhythm before treatment
C. Monitoring electrolyte levels
D. Performing vagal maneuvers in stable patients
Answer: A
Rationale: Adenosine is contraindicated in atrial fibrillation as it may worsen the rhythm; misinterpretation can lead to harmful interventions
A patient with known structural heart disease develops polymorphic VT. This is most consistent with: A. Stable SVT
B. Torsades de pointes
C. Sinus tachycardia
D. Atrial flutter
Answer:
Answer: B
Rationale: Polymorphic VT, especially with a twisting QRS pattern, is characteristic of torsades de pointes, often related to prolonged QT
Which antiarrhythmic drug is considered a “broad-spectrum” agent for treating ventricular dysrhythmias? A. Adenosine
B. Amiodarone
C. Digoxin
D. Verapamil
Answer: B
Rationale: Amiodarone is a broad-spectrum antiarrhythmic used in various tachyarrhythmias including VT and VF
In patients with refractory ventricular dysrhythmias, which of the following devices is considered for secondary prevention? A. Temporary pacemaker
B. Implantable cardioverter-defibrillator (ICD)
C. External defibrillator only
D. Beta-blocker pump
Answer: B
Rationale: An ICD is indicated for patients with a history of life-threatening ventricular dysrhythmias to prevent sudden cardiac death.
Which electrolyte abnormality is most commonly associated with the development of dysrhythmias? A. Hyperkalemia
B. Hypokalemia
C. Hypercalcemia
D. Hypophosphatemia
Answer: B
Rationale: Hypokalemia is a common electrolyte disturbance that can precipitate various dysrhythmias
Which condition is “really common” in patients with chronic heart failure and predisposes them to dysrhythmias? A. Enhanced vagal tone
B. Left ventricular remodeling and scar formation
C. Increased parasympathetic activity
D. Improved coronary perfusion
Answer: B
Rationale: Chronic heart failure often leads to remodeling and scar tissue formation, which predisposes patients to reentrant ventricular arrhythmias
What is the main purpose of obtaining a 12-lead EKG in a patient with suspected dysrhythmia? A. To diagnose electrolyte abnormalities
B. To precisely identify the type of dysrhythmia
C. To measure blood pressure
D. To determine the patient’s weight
Answer: B
Rationale: A 12-lead EKG is essential to classify the dysrhythmia (e.g., SVT, VT, AF, VF) and guide appropriate management
When managing a patient with pulseless ventricular tachycardia, what is the immediate management step? A. Synchronized cardioversion
B. Immediate defibrillation and initiation of ACLS protocols
C. Vagal maneuvers
D. Administration of adenosine
Answer: B
Rationale: In pulseless VT, immediate unsynchronized defibrillation is mandated as part of ACLS for shockable rhythms.
Which dysrhythmia is most likely to deteriorate into ventricular fibrillation and cause sudden cardiac death? A. Paroxysmal SVT
B. Sustained ventricular tachycardia
C. Sinus bradycardia
D. Atrial flutter
Answer: B
Rationale: Sustained VT can degenerate into ventricular fibrillation, which is a leading cause of sudden cardiac death.
Which factor is critical to assess when deciding whether a patient with a dysrhythmia is “stable” or “unstable”? A. The patient’s age
B. Hemodynamic status (e.g., blood pressure, level of consciousness)
C. The width of the QRS complex only
D. The presence of a history of dysrhythmias
Answer: B
Rationale: Hemodynamic stability (blood pressure, mental status, signs of shock) is key in determining immediate management (e.g., need for cardioversion
In treating dysrhythmias, which potential iatrogenic harm must be avoided when using electrical cardioversion? A. Underestimating the energy required
B. Delivering unsynchronized shocks leading to R-on-T phenomenon
C. Using adenosine in a pulseless rhythm
D. Administering beta blockers before the shock
Answer: B
Rationale: Unsynchronized shocks can fall on the vulnerable period of the cardiac cycle (T-wave), provoking VF.
What is a common adverse effect of amiodarone therapy that clinicians must monitor? A. Hyperkalemia
B. Hypothyroidism or hyperthyroidism
C. Acute kidney injury
D. Immediate arrhythmia termination without side effects
Answer: B
Rationale: Amiodarone can affect thyroid function, so thyroid monitoring is necessary during chronic therapy
Which of the following scenarios is most concerning (“what will kill your patient”) if left untreated? A. Atrial fibrillation with controlled rate in an asymptomatic patient
B. Sustained polymorphic VT (torsades de pointes) leading to hemodynamic collapse
C. Occasional premature atrial contractions
D. Sinus tachycardia due to fever
Answer: B
Rationale: Sustained torsades de pointes is life-threatening and can deteriorate into VF, resulting in cardiac arrest.
Which environmental or pharmacologic factor can precipitate dysrhythmias by altering electrolyte balance? A. High dietary fiber intake
B. Diuretic overuse leading to hypokalemia
C. Excessive water consumption
D. Routine exercise
Answer: B
Rationale: Overuse of diuretics may cause hypokalemia, a known precipitant of dysrhythmias.
In patients with ventricular dysrhythmias, why is it important to identify and treat reversible causes? A. They usually resolve on their own
B. They may be corrected to prevent recurrence and further cardiac arrest
C. They do not affect long-term management
D. Reversible causes are rare and not important
Answer: B
Rationale: Addressing reversible causes (electrolyte imbalances, ischemia, drug toxicity) is essential to prevent recurrent, potentially fatal dysrhythmias
Which of the following is a common physical examination finding in patients with dysrhythmias? A. A regular, slow pulse
B. Palpitations or irregular pulse rhythms
C. A completely silent heart on auscultation
D. A continuous murmur over the carotids
Answer: B
Rationale: Patients often report palpitations and may have an irregular pulse, especially in atrial fibrillation.
Which of the following EKG findings is most typical in ventricular fibrillation? A. Regular, narrow QRS complexes
B. Chaotic, irregular electrical activity with no discernible QRS complexes
C. Organized, wide QRS complexes
D. Normal sinus rhythm
Answer: B
Rationale: Ventricular fibrillation is characterized by chaotic electrical activity without organized QRS complexes, leading to no effective cardiac outpu
When managing dysrhythmias, what is the primary rationale for using beta blockers in stable patients? A. They increase heart rate and contractility
B. They decrease sympathetic tone, reducing automaticity and conduction velocity
C. They act as potent vasodilators
D. They have no effect on the conduction system
Answer: B
Rationale: Beta blockers reduce sympathetic stimulation, which helps control heart rate and reduce arrhythmic potential
Which scenario would be classified as an unstable dysrhythmia requiring immediate intervention? A. SVT with a heart rate of 160 bpm in a fully alert patient
B. Atrial fibrillation with rapid ventricular response in a patient with hypotension and altered mental status
C. Occasional premature ventricular contractions
D. Sinus tachycardia due to exercise
Answer: B
Rationale: Dysrhythmias causing hypotension, altered mental status, or signs of shock are unstable and necessitate urgent treatment.
What is the potential harm (“what will harm your patient”) of administering adenosine in the wrong clinical scenario? A. It can cause profound bradycardia or even asystole in patients with underlying conduction system disease
B. It always terminates atrial fibrillation
C. It has no side effects
D. It is contraindicated only in ventricular dysrhythmias
Answer: A
Rationale: Adenosine can provoke severe bradycardia or asystole if used inappropriately, particularly in patients with preexisting conduction abnormalities
Which of the following best summarizes the management principles for dysrhythmias? A. Always use electrical therapy first regardless of stability
B. Rapid identification, risk stratification (stable vs. unstable), addressing reversible causes, and using appropriate pharmacologic or electrical therapies based on the specific rhythm
C. Sole reliance on antiarrhythmic drugs without monitoring hemodynamics
D. Delaying treatment until all diagnostic tests are complete
Answer: B
Rationale: Management of dysrhythmias requires timely diagnosis, determination of stability, correction of reversible causes, and selecting the appropriate therapy (vagal maneuvers, medications, or cardioversion) based on the rhythm and patient status.
Which EKG finding is most concerning for impending ventricular fibrillation?
A. Regular, narrow QRS complexes
B. Rapid, monomorphic ventricular tachycardia
C. Polymorphic ventricular tachycardia with twisting of QRS complexes (Torsades de Pointes)
D. Sinus rhythm with premature atrial contractions
Answer: C
Rationale: Torsades de pointes is a form of polymorphic VT associated with prolonged QT interval and can degenerate into VF, making it life-threatening if not treated promptly.
Which scenario is considered an “unstable” dysrhythmia requiring immediate synchronized cardioversion?
A. SVT with a rate of 160 bpm in a patient who is asymptomatic
B. Atrial fibrillation with rapid ventricular response in a patient with hypotension and altered mental status
C. Occasional PVCs in a patient with a normal blood pressure
D. Sinus tachycardia secondary to fever
Answer: B
Rationale: Atrial fibrillation with rapid ventricular response in a patient with signs of hemodynamic instability (hypotension, altered mental status) is unstable and requires immediate cardioversion.
Which of the following is a potential iatrogenic harm when administering synchronized cardioversion?
A. Ensuring the patient is well-sedated
B. Delivering a shock unsynchronized, causing R-on-T phenomenon and potential induction of VF
C. Using a defibrillator with proper synchronization
D. Confirming the rhythm is shockable
Answer: B
Rationale: Unsynchronized shocks (R-on-T phenomenon) during cardioversion can provoke ventricular fibrillation, which is life-threatening
A patient with chronic heart failure presents with new-onset palpitations and an irregularly irregular rhythm on EKG. What is the most likely diagnosis?
A. Atrial fibrillation
B. Atrial flutter
C. Paroxysmal SVT
D. Ventricular tachycardia
Answer: A
Rationale: An irregularly irregular rhythm without distinct P waves is characteristic of atrial fibrillation, which is common in patients with chronic heart failure.
On CT angiography of a patient with an AAA, which finding is typically observed? A. Uniform narrowing of the aorta
B. Mural thrombus and calcifications within a dilated aortic segment
C. Diffuse pulmonary infiltrates
D. Normal aortic diameter with increased perfusion
Answer: B
Rationale: AAAs often demonstrate a dilated aorta with mural thrombus, calcifications, and irregular wall contours on imaging.
How does the EKG typically appear in patients with thoracic aortic dissection? A. It shows definitive ST-elevation myocardial infarction patterns
B. It is usually normal or nonspecific, helping to rule out MI
C. It demonstrates atrial fibrillation exclusively
D. It reveals prolonged QT intervals
Answer: B
Rationale: EKG findings in aortic dissection are often nonspecific, which helps differentiate dissection from an acute myocardial infarction
