A 72-year-old man is brought to the emergency department due to 3 days of worsening cough and shortness of breath. The cough is productive of a small amount of white sputum. The patient has no chest pain. He has a history of hypertension, gout, chronic obstructive pulmonary disease, and coronary artery disease for which he underwent coronary artery bypass grafting. He also had mitral valve repair 6 years ago. The patient has a 40-pack-year smoking history and continues to smoke a pack of cigarettes a day.
Blood pressure is 136/72 mm Hg, pulse is 132/min, and respirations are 26/min. Oxygen saturation is 92% on room air. The patient appears to be in moderate respiratory distress. Jugular venous pulse is difficult to measure due to use of accessory muscles. Lung auscultation shows decreased air entry in both lung fields. There is diffuse and scattered wheezing heard throughout the lung zones. Heart sounds are irregular with a faint holosystolic murmur heard over the cardiac apex. There is 1+ bilateral pitting ankle edema.
Laboratory results are as follows:
ECG is shown in the exhibit.
Which of the following is the best treatment for this patient's cardiac condition?

Question

A 72-year-old man is brought to the emergency department due to 3 days of worsening cough and shortness of breath.  The cough is productive of a small amount of white sputum.  The patient has no chest pain.  He has a history of hypertension, gout, chronic obstructive pulmonary disease, and coronary artery disease for which he underwent coronary artery bypass grafting.  He also had mitral valve repair 6 years ago.  The patient has a 40-pack-year smoking history and continues to smoke a pack of cigarettes a day.
Blood pressure is 136/72 mm Hg, pulse is 132/min, and respirations are 26/min.  Oxygen saturation is 92% on room air.  The patient appears to be in moderate respiratory distress.  Jugular venous pulse is difficult to measure due to use of accessory muscles.  Lung auscultation shows decreased air entry in both lung fields.  There is diffuse and scattered wheezing heard throughout the lung zones.  Heart sounds are irregular with a faint holosystolic murmur heard over the cardiac apex.  There is 1+ bilateral pitting ankle edema.
Laboratory results are as follows:
 ECG is shown in the exhibit. 
Which of the following is the best treatment for this patient's cardiac condition?

Quizplus · Accepted Answer

11ec193a_95dd_531e_853d_617b8d398ed8_MD0002_00 This patient's ECG demonstrates multifocal atrial tachycardia (MAT), a supraventricular tachyarrhythmia that most commonly occurs in elderly patients experiencing an acute exacerbation of underlying pulmonary disease. Chronic obstructive pulmonary disease (COPD) has the strongest association with MAT, but the arrhythmia is also seen with pneumonia, pulmonary embolism, and exacerbations of heart failure. Patients typically present with symptoms of the underlying illness, and the arrhythmia itself is typically asymptomatic. The diagnosis of MAT is confirmed by ECG findings of an atrial rate >100/min (tachycardia differentiates MAT from wandering atrial pacemaker), irregular R-R intervals, and distinct P waves with >3 different morphologies. Treatment is aimed at the inciting disturbance (eg, systemic corticosteroids and inhaled bronchodilators for this patient's COPD exacerbation). ECG findings Other potential causes of MAT include electrolyte imbalance (eg, hypokalemia, hypomagnesemia) and nonpulmonary conditions that lead to catecholamine surge (eg, sepsis). (Choice A) Rate control with a cardiac glycoside (eg, digoxin) or other agent that slows atrioventricular conduction (eg, beta blocker, nondihydropyridine calcium channel blocker) is sometimes useful in case of persistent MAT despite treatment of the inciting disturbance or in case of hemodynamic instability as a result of MAT (rare). However, this rarely leads to resolution of MAT. (Choice C) Electrical cardioversion is not effective in converting MAT to sinus rhythm and is not recommended. (Choices D and E) Antiarrhythmic drugs (eg, amiodarone, ibutilide) are often used for pharmacological cardioversion in patients with atrial fibrillation but are ineffective in the management of MAT. Educational objective: Multifocal atrial tachycardia most commonly occurs in elderly patients with an exacerbation of underlying pulmonary disease (eg, chronic obstructive pulmonary disease), and is characterized by ECG showing an atrial rate >100/min, irregular R-R intervals, and >3 distinct P wave morphologies. Treatment is aimed at correcting the underlying inciting disturbance. __________ References: Multifocal atrial tachycardia. (http://www.ncbi.nlm.nih.gov/pubmed/9440591)

A 72-Year-Old Man Is Brought to the Emergency Department Due