Clinical Information
36 year old female patient, a known case of rheumatic heart disease with mitral and aortic regurgitation (closed mitral valvotomy done for mitral stenosis 7 years ago), on digoxin, diuretics, oral potassium and erythromycin prophylaxis, was admitted with severe dyspnea and palpitations at rest. Clinically patient had irregular heart rate above 150/min, blood pressure 80/60 mm Hg and pulmonary edema. Electrocardiogram before and after 250 mg intravenous phenytoin sodium is shown below. What is your diagnosis?
Fig. 1.
Answer to ECG Quiz
Multifocal Atrial Tachycardia (MAT)
The ECG shows irregularly irregular tachycardia of rate 250/min with P waves of varying morphology (arrows). The two criteria required to meet the definition of MAT are a rate exceeding IOO/min and a minimum of three consecutive P waves of different morphology [1]. MAT may be a manifestation of digitalis toxicity, severe cardiac or pulmonary disease, hypokalemia or theophylline and adrenergic drug effect. Phenytoin is the drug of choice for digitalis-induced supraventricular and ventricular arrhythmias as illustrated in this case [2]. The concomitant administration of erythromycin probably precipitated digitalis toxicity [3].
References
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