Review Question - QID 103655

EKG shows more than three morphologically different P-waves, varying P–R intervals, tachycardia, and narrow QRS complexes, all consistent with multifocal atrial tachycardia (MAT), which is most likely related to his smoking history and obstructive lung disease.

MAT is most commonly associated with hypoxia and chronic obstructive pulmonary disease (COPD). This patient’s smoking history and lung abnormalities on physical exam suggest COPD as the likely etiology of his arrhythmia. MAT may also occur following acute MI, with hypokalemia or hypomagnesemia, or due to toxicity from drugs such as theophylline, isoproterenol, and digoxin.

Colluci et al. review supraventricular tachycardias. Risk factors for MAT include middle age, heart failure or chronic obstructive pulmonary disease. EKG characteristics of MAT include: three different P-wave morphologies (unrelated to each other) as well as RR interval irregularly.

Durham and Worthley review cardiac tachyarrhythmias. They report that MAT is a characteristic supraventricular tachycardia found commonly in critically ill patients. The treatment of choice is removal of the precipitating factor, but it may also respond to intravenous magnesium sulphate.

Figure A is an EKG classic for MAT with characteristics as described in the discussion.

Incorrect answers:
Answer 1: Alcohol use may lead to atrial fibrillation. Distinct P waves are not present in atrial fibrillation.
Answer 2: Chronic diabetes may lead to microvascular changes but is not associated with MAT.
Answer 3: Lisinopril is associated with several side effects but is not linked to MAT.
Answer 4: Chronic hypertension is not linked to MAT.