AF Flashcards
Which of the following best defines paroxysmal atrial fibrillation (AF)?
A. AF episodes that persist for more than 7 days but less than 1 year
B. AF that has been continuous for more than 1 year
C. AF episodes that occur spontaneously and terminate within 7 days
D. AF that requires medical intervention to terminate
Answer: C. AF episodes that occur spontaneously and terminate within 7 days
Rationale: Paroxysmal AF is defined as an episode of AF that occurs spontaneously and terminates within a short duration, typically ≤7 days. This distinguishes it from persistent AF, which lasts longer than 7 days, and long-standing persistent AF, which persists for over a year.
What is the primary pathophysiologic process that contributes to the progression of atrial fibrillation?
A. Single-point mutations in atrial tissue
B. Enhanced automaticity and atrial remodeling
C. Excessive sympathetic stimulation alone
D. Complete failure of the sinoatrial node
Answer: B. Enhanced automaticity and atrial remodeling
Rationale: The development and progression of AF involve enhanced automaticity, particularly in the pulmonary vein musculature, which leads to ectopic beats. Over time, structural and electrical remodeling occurs, shortening atrial refractory periods and promoting fibrosis, which sustains AF and makes its treatment more difficult.
Which of the following risk factors is not strongly associated with the development of atrial fibrillation?
A. Hypertension
B. Diabetes mellitus
C. Sleep-disordered breathing
D. Hyperthyroidism
Answer: D. Hyperthyroidism
Rationale: While hyperthyroidism can contribute to AF, it is not among the most commonly cited risk factors. The most strongly associated risk factors include cardiovascular disease, obesity, hypertension, diabetes mellitus, and sleep-disordered breathing, which all contribute to structural and electrical changes in the atria.
Which anatomical region is most commonly implicated as the source of ectopic beats that initiate atrial fibrillation?
A. Sinoatrial node
B. Atrioventricular node
C. Pulmonary veins
D. Left ventricular myocardium
Answer: C. Pulmonary veins
Rationale: The pulmonary veins contain myocardial extensions that exhibit enhanced automaticity, making them a frequent site of ectopic beats that initiate AF. Other regions such as the superior vena cava, coronary sinus, and the remnant of the vein of Marshall may also contribute, but the pulmonary veins are the most commonly involved.
Why does persistent atrial fibrillation become more difficult to treat over time?
A. It is associated with a genetic mutation that worsens with age
B. Atrial tissue undergoes remodeling, leading to fibrosis and refractory period shortening
C. Medications used to treat AF lose their efficacy over time
D. The immune system starts attacking atrial cells, worsening the disease
Answer: B. Atrial tissue undergoes remodeling, leading to fibrosis and refractory period shortening
Rationale: As AF persists, structural and electrical changes occur in atrial tissue, including fibrosis and shortening of refractory periods. These changes promote sustained AF and reduce the effectiveness of therapeutic interventions, making sinus rhythm restoration more challenging.
What is the primary mechanism by which AF contributes to stroke risk?
A. Coronary artery plaque rupture
B. Hypotension leading to cerebral hypoperfusion
C. Thrombus formation in the left atrial appendage
D. Direct embolization from pulmonary veins
Answer: C. Thrombus formation in the left atrial appendage
Rationale: In AF, the loss of atrial contraction leads to blood stasis, particularly in the left atrial appendage, where thrombi can form and embolize, causing ischemic strokes. This risk is why anticoagulation therapy is often used in patients with AF.
Which of the following best describes the impact of rapid ventricular rates in AF on cardiac output?
A. Consistently increased stroke volume
B. Irregular ventricular filling leading to variable stroke volume
C. No effect on cardiac output
D. Increased atrial contribution to ventricular filling
Answer: B. Irregular ventricular filling leading to variable stroke volume
Rationale: The irregular, rapid ventricular rates in AF lead to inconsistent ventricular filling times, causing variable stroke volumes. This results in symptoms such as fatigue, exercise intolerance, and dyspnea. Additionally, loss of atrial systole further reduces cardiac output, particularly in patients with underlying heart disease.
What is “stiff left atrial syndrome” in the context of atrial fibrillation?
A. A form of congenital atrial dysfunction
B. A consequence of long-standing persistent AF leading to fibrosis and impaired compliance of the left atrium
C. A transient condition occurring immediately after cardioversion
D. A term used to describe atrial spasm due to excessive sympathetic stimulation
Answer: B. A consequence of long-standing persistent AF leading to fibrosis and impaired compliance of the left atrium
Rationale: Long-standing AF leads to atrial remodeling, fibrosis, and dilation, resulting in reduced atrial compliance and elevated filling pressures. This condition, referred to as “stiff left atrial syndrome,” can contribute to volume overload and heart failure symptoms.
Which of the following is an indication for emergent electrical cardioversion in a patient with AF?
A. Patient is asymptomatic with a ventricular rate of 90 bpm
B. Patient has mild palpitations and no hemodynamic instability
C. Patient has hemodynamic compromise, pulmonary edema, or coronary ischemia
D. Patient has had AF for more than 10 years and is currently stable
Answer: C. Patient has hemodynamic compromise, pulmonary edema, or coronary ischemia
Rationale: Emergent cardioversion is recommended for patients with AF who exhibit significant hemodynamic instability, pulmonary edema, or signs of acute coronary ischemia. Stable patients should first be managed with rate control and anticoagulation.
In hemodynamically stable patients with new-onset AF of unknown duration, why is anticoagulation recommended before cardioversion?
A. To reduce the risk of torsades des pointes
B. To prevent thromboembolism due to left atrial thrombi dislodging during cardioversion
C. To lower blood pressure before electrical cardioversion
D. To minimize inflammation in the pulmonary veins
Answer: B. To prevent thromboembolism due to left atrial thrombi dislodging during cardioversion
Rationale: If AF has lasted longer than 48 hours or the duration is unknown, cardioversion can dislodge thrombi from the left atrial appendage, leading to stroke or systemic embolism. Anticoagulation for at least 4 weeks before cardioversion or a transesophageal echocardiogram (TEE) to rule out thrombi is recommended.
Which of the following is true regarding ibutilide for pharmacologic cardioversion?
A. It is a class III antiarrhythmic with a risk of torsades des pointes
B. It should be used in all patients regardless of QT interval duration
C. It is preferred over electrical cardioversion in hemodynamically unstable patients
D. It is only effective for rate control and does not restore sinus rhythm
Answer: A. It is a class III antiarrhythmic with a risk of torsades des pointes
Rationale: Ibutilide is a class III antiarrhythmic that can restore sinus rhythm but carries a risk of torsades des pointes, especially in patients with prolonged QT intervals or severe left ventricular dysfunction. It is not recommended for hemodynamically unstable patients, where electrical cardioversion is preferred.
Which imaging modality is most commonly used to evaluate for left atrial appendage thrombus before cardioversion?
A. Transthoracic echocardiography (TTE)
B. Transesophageal echocardiography (TEE)
C. Chest X-ray
D. Coronary angiography
Answer: B. Transesophageal echocardiography (TEE)
Rationale: TEE is the preferred imaging modality to assess for left atrial appendage thrombus because of its high sensitivity and specificity. CT angiography is also an option, but TEE remains the most widely used in clinical practice.
What is the primary source of thromboembolism in atrial fibrillation (AF)?
A. Right atrium
B. Pulmonary veins
C. Left atrial appendage
D. Left ventricular apex
Answer: C. Left atrial appendage
Rationale: The left atrial appendage is the most common site for thrombus formation in AF due to blood stasis. While thrombi can form in other locations, the relative stagnation of blood flow in this region significantly increases the risk of embolism and stroke.
In which of the following patients can cardioversion be performed within 48 hours without prior anticoagulation?
A. A patient with a CHA₂DS₂-VASc score of 4 and AF lasting 72 hours
B. A patient with a history of rheumatic mitral stenosis and AF for 24 hours
C. A patient with hypertrophic cardiomyopathy and marked left atrial enlargement
D. A patient with no prior embolic events, no mitral stenosis, and AF lasting 12 hours
Answer: D. A patient with no prior embolic events, no mitral stenosis, and AF lasting 12 hours
Rationale: Cardioversion within 48 hours is considered safe in low-risk patients without a history of embolism, rheumatic mitral stenosis, or hypertrophic cardiomyopathy. If AF lasts longer than 48 hours, or the patient is at high risk, anticoagulation is required before cardioversion.
What is the recommended anticoagulation strategy for a patient with AF lasting >48 hours before cardioversion?
A. No anticoagulation is needed before cardioversion
B. Anticoagulation for at least 3 weeks before and 4 weeks after cardioversion
C. Immediate cardioversion without any prior anticoagulation
D. Anticoagulation for 4 weeks post-cardioversion only, with no prior therapy
Answer: B. Anticoagulation for at least 3 weeks before and 4 weeks after cardioversion
Rationale: If AF has lasted >48 hours or the duration is unknown, anticoagulation for at least 3 weeks before and 4 weeks after cardioversion is recommended.
There are two approaches to mitigate the risk related to cardioversion. One option is to anticoagulate continuously for 3 weeks before and a minimum of 4 weeks after cardioversion. A second approach is to start anticoagulation and perform a TEE or high-resolution cardiac CT scan to detect the presence of thrombus in the left atrial appendage. If thrombus is absent, cardioversion can be performed and anticoagulation continued for a minimum
of 4 weeks to allow time for recovery of atrial mechanical function
What is the primary goal of acute rate control in atrial fibrillation (AF)?
A. To convert AF to sinus rhythm
B. To allow more diastolic filling time and improve cardiac output
C. To prevent the need for anticoagulation
D. To eliminate ectopic atrial beats
Answer: B. To allow more diastolic filling time and improve cardiac output
Rationale: Acute rate control in AF aims to slow ventricular response, allowing more time for diastolic filling. This improves cardiac output and reduces symptoms. Unlike rhythm control, it does not aim to restore sinus rhythm.
Which of the following is an acceptable heart rate target for chronic rate control in AF?
A. Resting heart rate <50 bpm, exertional rate <70 bpm
B. Resting heart rate <80 bpm, exertional rate <100 bpm
C. Resting heart rate <100 bpm, exertional rate <130 bpm
D. Resting heart rate <120 bpm with no exertional limitation
Answer: B. Resting heart rate <80 bpm, exertional rate <100 bpm
Rationale: Chronic rate control aims for a resting heart rate <80 bpm, with an increase to <100 bpm on light exertion. If these targets are difficult to achieve, a resting rate of up to 110 bpm is acceptable as long as symptoms and ventricular function remain stable.
What is a potential complication of the “ablate and pace” strategy for AF management?
A. Increased risk of thromboembolism
B. Complete AV block leading to asystole
C. Ventricular dyssynchrony from right ventricular pacing
D. Increased likelihood of spontaneous conversion to sinus rhythm
Answer: C. Ventricular dyssynchrony from right ventricular pacing
Rationale: In the “ablate and pace” strategy, destruction of the AV node results in pacemaker dependence. Right ventricular pacing from the apex can lead to dyssynchronous ventricular contraction, which may impair ventricular function. Alternative pacing techniques (e.g., biventricular or His bundle pacing) can minimize this issue.
Which anticoagulant has an available reversal agent called idarucizumab?
A. Warfarin
B. Dabigatran
C. Rivaroxaban
D. Apixaban
Answer: B. Dabigatran
Rationale: Idarucizumab is a specific reversal agent for dabigatran, while andexanet alfa is used for factor Xa inhibitors like rivaroxaban and apixaban.
Which of the following scoring systems is commonly used to assess stroke risk in patients with atrial fibrillation?
A. HAS-BLED
B. CHA₂DS₂-VASc
C. TIMI Score
D. SOFA Score
Answer: B. CHA₂DS₂-VASc
Rationale: The CHA₂DS₂-VASc scoring system is widely used to estimate stroke risk in AF patients, guiding anticoagulation decisions.
What is the minimum CHA₂DS₂-VASc score at which anticoagulation is generally recommended (excluding female gender as a lone risk factor)?
A. 0
B. 1
C. 2
D. 3
Answer: B. 1
Rationale: In the U.S., anticoagulation is recommended for a CHA₂DS₂-VASc score of ≥1 in males and ≥2 in females, unless the only risk factor is female gender.
What is the primary reason for using the HAS-BLED scoring system in atrial fibrillation management?
A. To determine stroke risk
B. To assess bleeding risk
C. To predict mortality
D. To assess left atrial thrombus formation
Answer: B. To assess bleeding risk
Rationale: The HAS-BLED score evaluates bleeding risk in AF patients to balance anticoagulation benefits against potential complications.
Which risk factor in the CHA₂DS₂-VASc scoring system carries two points instead of one?
A. Hypertension
B. Diabetes mellitus
C. Prior stroke or TIA
D. Age 65-74
Answer: C. Prior stroke or TIA
Rationale: Stroke or transient ischemic attack (TIA) carries 2 points in the CHA₂DS₂-VASc score due to the high risk of recurrent embolic events.
A 70-year-old female patient with a history of prior stroke and hypertension is being evaluated for anticoagulation. What is her CHA₂DS₂-VASc score?
A. 3
B. 4
C. 5
D. 6
Answer: C. 5
Rationale:
Age >65 = 1 point
Hypertension = 1 point
Prior stroke = 2 points
Female sex = 1 point
Total = 5 points, indicating a high stroke risk and the need for anticoagulation.
A 68-year-old patient on warfarin for atrial fibrillation has the following risk factors: hypertension, chronic alcohol use, and a history of labile INR. What is his HAS-BLED score?
A. 2
B. 3
C. 4
D. 5
Answer: C. 4
Rationale:
Hypertension = 1 point
Age >65 = 1 point
Labile INR (on warfarin) = 1 point
Alcohol use = 1 point
Total = 4 points, indicating an increased risk of bleeding and the need for careful monitoring of anticoagulation therapy.
A 62-year-old patient with symptomatic paroxysmal AF and difficulty achieving rate control is being considered for rhythm control. Which treatment option is most appropriate based on recent evidence?
A. Immediate initiation of beta-blockers
B. Long-term digoxin therapy
C. Early catheter ablation
D. Warfarin monotherapy
Answer: C. Early catheter ablation
Rationale: Recent trials suggest that early rhythm control, including catheter ablation, improves outcomes in symptomatic AF patients. It is increasingly being considered earlier in the course of treatment, especially in paroxysmal AF.
Which of the following statements about rhythm control in AF is correct?
A. Antiarrhythmic drugs improve survival compared to rate control
B. Catheter ablation has been shown to reduce hospitalization rates in heart failure patients
C. Anticoagulation can be discontinued if sinus rhythm is maintained
D. Rhythm control is generally preferred in elderly, sedentary patients
Answer: B. Catheter ablation has been shown to reduce hospitalization rates in heart failure patients
Rationale: A large randomized trial demonstrated a trend toward reduced hospitalizations and improved outcomes in AF patients, particularly those with heart failure, who underwent catheter ablation. Anticoagulation should not be discontinued even if sinus rhythm appears maintained due to the risk of silent AF episodes.
A 55-year-old patient with frequent symptomatic AF episodes despite rate control therapy is not a candidate for catheter ablation. What is the next best step in management?
A. Continue rate control therapy
B. Initiate or adjust antiarrhythmic drug therapy
C. Discontinue anticoagulation
D. Perform left atrial appendage closure
Answer: B. Initiate or adjust antiarrhythmic drug therapy
Rationale: If a patient continues to have frequent symptomatic AF episodes despite rate control, a rhythm control strategy using antiarrhythmic medications is appropriate, particularly if catheter ablation is not an option. Anticoagulation should still be maintained based on CHA₂DS₂-VASc risk.
A 68-year-old patient with coronary artery disease (CAD) and paroxysmal AF is started on sotalol for rhythm control. Which of the following is the most important safety concern with this medication?
A. Increased risk of pulmonary fibrosis
B. Risk of QT prolongation and torsades de pointes
C. Increased risk of bradycardia
D. Risk of thyroid dysfunction
Answer: B. Risk of QT prolongation and torsades de pointes
Rationale: Sotalol and dofetilide are class III antiarrhythmic drugs that carry a ~3% risk of excessive QT prolongation and torsades de pointes, requiring careful ECG monitoring, particularly at initiation.
Which antiarrhythmic medication is most effective for maintaining sinus rhythm in AF but has a high incidence of long-term toxicities?
A. Flecainide
B. Amiodarone
C. Dronedarone
D. Propafenone
Answer: B. Amiodarone
Rationale: Amiodarone is the most effective antiarrhythmic for maintaining sinus rhythm, with ~66% success rate, but >40% of patients experience long-term toxicities, including pulmonary fibrosis, thyroid dysfunction, and liver toxicity.
