Clinical Challenge: Elderly Man Presents With Dyspnea at Rest and Chronic Cough
Testing shows normal brain natriuretic peptide level and negative troponins but elevated serum bicarbonate level and evidence of metabolic alkalosis.
Answer: D. COPD exacerbation with multifocal atrial tachycardia
Multifocal atrial tachycardia (MAT) is a common arrhythmia in patients with COPD and often triggered by COPD exacerbations. Note that in the electrocardiogram above the ventricular rate is approximately 125 bpm, and that most narrow QRS complexes are preceded by P waves of differing morphology. The diagnosis of MAT requires a heart rate greater than 100 bpm with organized atrial activity with P waves of 3 or more distinct morphologies.
MAT is often confused with atrial fibrillation, which is also common in patients with COPD but is managed differently (often with electrical cardioversion and anticoagulation).1 The development of MAT in COPD has been associated with increased atrial-triggered activity as a result of increased intracellular calcium driven by hypokalemia, hypoxia, acidemia, and increased circulating catecholamines.1
Unlike the relationship between atrial fibrillation and COPD, MAT is a poor prognostic marker in COPD, especially in patients requiring ventilation.1 MAT is usually not treated, but rather the aim of therapy should be to treat the underlying cause (ie, the COPD exacerbation). However, there may be situations where MAT is persistent and the tachycardia is contributing to the patient's deteriorating clinical status. The mainstay of treatment in these situations is beta-1 selective beta-blockers such as metoprolol or esmolol, magnesium, and non-dihydropyridine calcium channel blockers such as verapamil. Electrical cardioversion is usually not helpful and thus is not recommended.
Goudis CA, Konstantinidis AK, Ntalas IV, Korantzopoulos P. Electrocardiographic abnormalities and cardiac arrhythmias in chronic obstructive pulmonary disease. Int J Cardiol. 2015;199:264-273.