FNP Atrial Fibrillation Practice Questions

The primary goal for this patient is rate control in the setting of structural heart disease. Because he has a reduced ejection fraction, non-dihydropyridine calcium channel blockers like diltiazem and verapamil are strictly contraindicated due to their negative inotropic effects, which can severely worsen heart failure symptoms and decrease cardiac output. Digoxin is an option for rate control but is generally considered second-line because it lacks the proven mortality benefits associated with beta-blockers in heart failure patients. Therefore, initiating a cardioselective beta-blocker like metoprolol succinate is the safest and most effective evidence-based choice. It provides excellent atrioventricular nodal blockade to lower the heart rate while simultaneously managing and improving his underlying heart failure over the long term.

Managing rate control in a patient with borderline or low blood pressure requires careful medication selection. Beta-blockers like metoprolol and non-dihydropyridine calcium channel blockers like diltiazem or verapamil are highly effective at slowing the heart rate, but they also exert significant negative inotropic and vasodilatory effects. In a patient with a blood pressure of 92/60 mm Hg, initiating these agents could easily precipitate symptomatic hypotension or cardiogenic shock. Digoxin is the most appropriate choice in this scenario because it increases vagal tone to slow conduction through the atrioventricular node without lowering systemic blood pressure. While it is often a second-line agent for general rate control, its neutral effect on blood pressure makes it uniquely suited for hypotensive patients.

Multifocal atrial tachycardia is characterized by an irregularly irregular narrow QRS rhythm with at least three distinct P wave morphologies in the same lead, commonly seen in patients with severe pulmonary disease like COPD. Option A is incorrect because atrial fibrillation lacks discernible P waves entirely, presenting instead with fibrillatory waves. Option B is incorrect because atrial flutter features uniform sawtooth flutter waves rather than distinct, variable P waves. Option D is incorrect because while sinus tachycardia with PACs can be irregular, the underlying sinus P waves remain uniform, unlike the variable atrial pacemakers driving MAT.

The presence of occasional early beats that are preceded by distinct P waves of different morphology indicates premature atrial contractions. Paroxysmal atrial fibrillation episodes would present with an irregularly irregular rhythm and completely absent P waves during the event, not isolated early beats. Isolated premature ventricular complexes present as early, wide QRS complexes without preceding P waves, originating from the ventricles. A benign wandering atrial pacemaker features at least three different P wave morphologies but maintains an irregular rhythm without necessarily presenting as distinct early, skipped beats. Identifying these subtle ECG differences helps avoid unnecessary interventions.

The standard initial diagnostic test for any patient presenting with a new irregularly irregular pulse is to order a standard electrocardiogram test to definitively confirm the presence of atrial fibrillation. Applying a continuous Holter monitor is reserved for evaluating paroxysmal symptoms when the baseline ECG is completely normal. Obtaining a transthoracic echocardiogram study is important for assessing structural heart disease once atrial fibrillation is confirmed, but it is not the first diagnostic step. Checking serum thyroid stimulating hormone is a necessary laboratory evaluation for new-onset atrial fibrillation, yet the rhythm must first be definitively diagnosed via ECG before pursuing secondary causes.

Clarithromycin is a potent P-glycoprotein inhibitor that decreases digoxin clearance, leading to elevated serum concentrations and digoxin toxicity. Severe nausea and palpitations are classic signs requiring immediate evaluation with an ECG and serum level. Option B is incorrect because while macrolides cause GI upset, palpitations suggest a dangerous cardiac arrhythmia. Option C is flawed because other macrolides like erythromycin share this same severe drug interaction. Option D ignores the potential for life-threatening toxicity by treating the symptoms as simple gastrointestinal irritation.

Somatic tremors, common in Parkinson disease, can create an irregularly undulating baseline that mimics coarse atrial fibrillation in the limb leads. However, the presence of regular R-R intervals and visible P waves in lead V1 confirms an underlying normal sinus rhythm. Option A is incorrect because true atrial fibrillation must have an irregularly irregular ventricular response without true P waves. Option B is incorrect because atrial flutter would show consistent sawtooth waves rather than chaotic tremor artifact. Option C is incorrect because a wandering atrial pacemaker requires varying P wave morphologies, not just baseline artifact. Always check multiple leads to differentiate tremor artifact from true arrhythmias.

An irregularly irregular pulse in an older adult with a history of poorly controlled hypertension is the hallmark presentation of atrial fibrillation. Premature atrial contractions can cause occasional pulse irregularities but do not produce a sustained irregularly irregular rhythm. Sustained ventricular tachycardia is a regular, wide-complex rhythm that usually causes hemodynamic instability. Multifocal atrial tachycardia is irregular but is almost exclusively seen in patients with severe pulmonary disease.

When evaluating an older adult with fatigue and palpitations, an ECG showing an irregularly irregular rhythm with absent P waves is the classic hallmark of atrial fibrillation. This presentation distinguishes it from frequent premature atrial contractions, which would still display visible P waves before the early beats. Atrial flutter typically presents with a regular ventricular response and distinct sawtooth waves rather than a chaotic baseline. Multifocal atrial tachycardia does feature an irregular rhythm, but you would clearly see at least three distinct P wave morphologies rather than an absence of P waves. Recognizing these subtle ECG differences is essential for accurate diagnosis, as older adults often present with vague symptoms like worsening fatigue rather than classic palpitations, making the ECG findings the definitive diagnostic tool for guiding subsequent stroke prevention and rate control strategies.

This patient's COPD is a qualifying comorbidity that necessitates combination therapy or a respiratory fluoroquinolone. However, he is taking sotalol, an antiarrhythmic with a severe QT prolongation risk. This contraindicates the use of moxifloxacin, levofloxacin, and azithromycin, which all further prolong the QT interval and risk fatal arrhythmias. The combination of a beta-lactam and doxycycline provides the necessary broad coverage without affecting the QT interval.