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Therapeutic Theophylline Levels and Adverse Cardiac Events
The Editors welcome submissions for possible publication in the Letters section. Authors of letters should:
•Include no more than 300 words of text, three authors, and five references
•Type with double-spacing
•Send three copies of the letter, an authors' form signed by all authors, and a cover letter describing any conflicts of interest related to the contents of the letter.
Letters commenting on an Annals article will be considered if they are received within 6 weeks of the time the article was published. Only some of the letters received can be published. Published letters are edited and may be shortened; tables and figures are included only selectively. Authors will be notified that the letter has been received. If the letter is selected for publication, the author will be notified about 3 weeks before the publication date. Unpublished letters cannot be returned.
Annals welcomes electronically submitted letters.
TO THE EDITOR:
The recent article by Shannon and colleagues [1] clearly showed the severity of theophylline intoxication. Nearly one quarter of their patients had clinically significant complications when theophylline concentrations were in the toxic range. Of particular interest were patients who developed myocardial infarctions. Adverse cardiovascular effects can occur even when serum theophylline concentrations are in the therapeutic range. We followed a 61-year-old white woman who experienced an unusual combination of complications during treatment with intravenous aminophylline and nebulized albuterol. She had no history of heart disease except for left ventricular hypertrophy confirmed by echocardiography. A dynamic left ventricular outflow tract obstruction developed, which led to a myocardial infarction. Her serum theophylline level was 11.2 mg/L. Cardiac catheterization showed no fixed coronary artery stenoses. Hemodynamic changes resolved after discontinuation of aminophylline therapy. Bittar and colleagues [2] previously showed that aminophylline can cause tachycardia and myocardial ischemia, even at recommended doses. Aminophylline is a positive inotrope and has been reported to induce dynamic left ventricular outflow obstruction [3]. Moreover, it antagonizes the vasodilatory effect of adenosine on coronary arteries [4]. All these mechanisms can provoke myocardial ischemia and, as in our patient, myocardial infarction.
The Editors welcome submissions for possible publication in the Letters section. Authors of letters should:
•Include no more than 300 words of text, three authors, and five references
•Type with double-spacing
•Send three copies of the letter, an authors' form signed by all authors, and a cover letter describing any conflicts of interest related to the contents of the letter.
Letters commenting on an Annals article will be considered if they are received within 6 weeks of the time the article was published. Only some of the letters received can be published. Published letters are edited and may be shortened; tables and figures are included only selectively. Authors will be notified that the letter has been received. If the letter is selected for publication, the author will be notified about 3 weeks before the publication date. Unpublished letters cannot be returned.
Annals welcomes electronically submitted letters.
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