A Roentgenkymographic Study of the Heart in Myasthenia Gravis

Abstract

The roentgenkymograph has been established as a helpful adjunct in the study of certain diseases of the heart. It is generally recognized that the main value of this instrument is its ability to record permanently the motion of an organ observed fluoroscopically. In 1939, changes in the cardiac motion of a patient with myasthenia gravis were detected by the author fluoroscopically while examining the effects of prostigmine on the hypopharynx (4). Inasmuch as all previous cardiac studies in myasthenia gravis had been reported negative (8), the observation was considered preliminary until the kymograph, by recording the pulsations objectively, appeared to confirm the finding. Similar observations were then made on several other patients with myasthenia gravis. The kymograms showed a slight slowing of the pulse, with minor but definite changes in the waves along the left ventricular border after a test dose of prostigmine. In normal young adults used as controls, kymographic changes similar to those found in myasthenia gravis patients could be obtained by the same technic. This indicated that we were dealing with a pharmacologic action of prostigmine and not a sign characteristic of a specific disease entity. Further studies then were carried out. An effort was made to detect minor differences in the kymographic wave forms of normal subjects as compared with myasthenia gravis patients, and an explanation was sought for the kymographic changes observed following a test dose of prostigmine2 when other cardiac studies were negative in the same patients. The work was stimulated by a personal communication from Dr. Sidney Lange of Cincinnati, who had previously made a single cardiac roentgenkymogram on one of his patients with myasthenia gravis. Although the kymogram showed changes which he was unable to explain, he did not consider the single observation of sufficient importance to justify publication. To our knowledge, Dr. Lange is the only previous worker to use the roentgenkymograph in the study of this disease. The purpose of this paper is to record our findings and to call attention to certain variables which limit the use of the kymograph in studies of this type. Method Four normal persons and 16 patients with myasthenia gravis were examined. The patients with myasthenia gravis had been extensively studied at the Myasthenia Gravis Clinic of the Massachusetts General Hospital and represented typical cases of the disease. If the patient had been receiving prostigmine, this drug was withdrawn for twelve or more hours before the examination. During this period symptoms of lassitude, general muscle weakness, ptosis, dysphagia, dysarthria, and other signs of myasthenia gravis usually developed. A roentgenkymogram of the heart was then made. If the initial film was satisfactory, 1.5 to 2.0 mg. of prostigmine methylsulfate with 0.6 mg. of atropine sulfate was given intramuscularly (5). Fifteen minutes later a second roentgenkymogram was obtained.