Publications by authors named "Mark E Silverman"

Murmurs were described first by Laennec in 1819, after which the significance of a murmur became a matter of debate. By the late 19th century, many physicians regarded systolic murmurs as "organic," whereas others believed that they were often "functional." Samuel Levine became a central figure in separating functional from organic systolic murmurs.

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An unusual electrocardiogram was sent to Dr. J. Willis Hurst, who had no knowledge of the clinical details.

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In his landmark "Gulstonian Lectures on Malignant Endocarditis," published in 1885, William Osler commented, "Few diseases present greater difficulties in the way of diagnosis than malignant endocarditis, difficulties which in many cases are practically insurmountable." At that time, the fields of microbiology and blood cultures were in their infancy, and the diagnosis was made premortem in just half the patients with the condition. After Osler's report, extracardiac physical findings became essential clues to earlier diagnosis.

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In 1839, Jan Evangelista Purkinje discovered a net of gelatinous fibres in the subendocardium of the heart. Walter Gaskell in the 1880s observed that the impulse of the heart began in the sinus venosus, and that this region had the most rhythmic ability. A conducting bundle between the atrium and the ventricle was found by Wilhelm His, Jr in 1893.

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Primary pulmonary artery leiomyosarcomas are rare, and the diagnosis is usually confused with other, more common, diseases, especially pulmonary embolism. A 52-year-old male, previously healthy, sustained a cardiac arrest. Chest CT-angiography diagnosed a "saddle embolus".

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Why does the heart beat? This question--known as the myogenic versus neurogenic theory--dominated cardiac research in the 19th century. In 1839, Jan Evangelista Purkinje discovered gelatinous fibers in the ventricular subendocardium that he thought were muscular. Walter Gaskell, in 1886, demonstrated specialized muscle fibers joining the atria and ventricles that caused "block" when cut and found that the sinus venosus was the area of first excitation of the heart.

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Electrical cardioversion of atrial fibrillation was initially very controversial. The procedure was carefully developed by Bernard Lown and his associates who experimented first on animals and then on postoperative patients using a direct-current technique designed to avoid the vulnerable period. Their results, published in 1963, were soon accepted, and the procedure became a major therapeutic advance in the treatment of heart disease.

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Woldemar Mobitz, an early 20th century German internist, analyzed arrhythmias by graphing the relationship of changing atrial rates and premature beats to AV conduction. Through an astute mathematical approach, he was able to classify second-degree atrioventricular block into 2 types, subsequently referred to as Mobitz type I (Wenckebach) and Mobitz type II (Hay). Type I AV block was most often due to digitalis and was reversible.

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Walter Holbrook Gaskell was a nineteenth-century British physiologist whose investigations from 1874 until 1889 became central to our current understanding of cardiac physiology. His many cardiac contributions include the following: 1) the recognition of certain inherent properties of cardiac muscle; 2) the experimental proof that led to the acceptance of the myogenic theory of the origin of the heartbeat; 3) the mapping of the anatomy of the sympathetic nervous system; 4) the understanding of the dual autonomic control of the heart; 5) the discovery of the vasodilating effect of sympathetic stimulation on blood flow through skeletal muscle arteries; and 6) the introduction of the concept of heart block. Gaskell's elucidation of the sequence of cardiac contraction and atrioventricular block and his concepts of rhythmicity, excitability, contractility, conductivity and tonicity provided the physiologic explanation necessary for the future understanding of cardiac rhythm disturbances.

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