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Difficulty: HardCardiovascular System

A 7272-year-old man is brought to the emergency department by his daughter due to a 22-day history of progressively worsening shortness of breath, a cough productive of yellow sputum, and palpitations. His medical history is significant for hypertension, hyperlipidemia, and chronic obstructive pulmonary disease (COPD). He has a 5050-pack-year smoking history. Current medications include inhaled tiotropium, inhaled fluticasone, and oral amlodipine. His temperature is 37.6∘C37.6^\circ\text{C} (99.7∘F99.7^\circ\text{F}), blood pressure is 138/86138/86 mmHg, pulse is 134134/min and irregular, and respirations are 2626/min. Pulse oximetry is 87%87\% on room air. Physical examination reveals a barrel chest with prominent use of accessory muscles of respiration. Lung auscultation demonstrates a prolonged expiratory phase and diffuse wheezing bilaterally. There is no jugular venous distention or peripheral edema. An electrocardiogram reveals an irregular rhythm with narrow QRS complexes, absent flutter waves, and 33 distinct P wave morphologies in lead II. Which of the following is the most appropriate initial management for this patient?

  1. Administration of supplemental oxygen and nebulized ipratropium-albuterolAnswer
  2. B
    Administration of intravenous furosemide
  3. C
    Administration of intravenous piperacillin-tazobactam
  4. D
    Administration of intravenous diltiazem
  5. E
    Immediate synchronized electrical cardioversion

Answer

The correct answer is the administration of supplemental oxygen and nebulized ipratropium-albuterol.
The correct answer involves treating the underlying pulmonary cause. This patient's electrocardiogram shows multifocal atrial tachycardia (MAT), characterized by a heart rate >100> 100/min, irregular R-R intervals, and at least 33 different P wave morphologies in the same lead. MAT is strongly associated with severe pulmonary disease, particularly chronic obstructive pulmonary disease (COPD) exacerbations, which lead to hypoxia and right atrial stretch. The primary and most effective initial management for MAT is optimizing the patient's pulmonary status and oxygenation (e.g., supplemental oxygen, bronchodilators, and corticosteroids). Antiarrhythmic therapy is not indicated as first-line treatment.

Step-by-Step Solution

1
Analyze the patient's clinical presentation.
The patient is a 72-year-old man with a history of COPD presenting with worsening dyspnea, productive cough, hypoxia, and diffuse wheezing, indicating an acute COPD exacerbation.
To establish the primary underlying pathophysiology driving the patient's symptoms.
2
Interpret the electrocardiogram (ECG) findings.
The ECG shows an irregularly irregular narrow-complex tachycardia with three distinct P wave morphologies and an isoelectric baseline, which is diagnostic of multifocal atrial tachycardia (MAT).
To identify the specific cardiac rhythm abnormality.
3
Determine the appropriate management for the identified condition.
MAT is most commonly secondary to underlying pulmonary disease, hypoxia, or right atrial stretch. The first-line therapy is correcting the underlying cause rather than administering primary antiarrhythmic medications.
To select the safest and most effective initial intervention.
4
Select the best pharmacologic option based on the primary etiology.
Supplemental oxygen (to correct hypoxia) and bronchodilators like ipratropium-albuterol (to treat the COPD exacerbation) represent the most appropriate initial management.
Optimizing pulmonary function typically resolves MAT without the need for rate-controlling drugs.

Key Concept

Multifocal Atrial Tachycardia (MAT) is an irregularly irregular supraventricular arrhythmia characterized by ≥3\ge 3 distinct P wave morphologies. It is most often caused by exacerbation of underlying pulmonary disease (e.g., COPD), and initial management focuses on treating the underlying respiratory condition rather than administering antiarrhythmic drugs.
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Topics

Cardiovascular System

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