Samuel A. Levine and the history of grading systolic murmurs.

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. Freeman and Levine's 1933 study of 1,000 "noncardiac" subjects determined the frequency, cause, and significance of systolic murmurs. Murmurs were rated on a scale of 1 to 6 grades of intensity. Approximately 20% of their patients had grade 1 or 2 systolic murmurs. Hypertension, fever, tachycardia, and anemia were common factors, and the murmurs were considered functional because they would often disappear when these causes were controlled. Of 19 subjects with grade 3 or 4 murmurs, all were determined to have organic heart disease or anemia. Thus, louder systolic murmurs were found to be a significant finding, as were the cause, location, and effects of posture. They concluded that systolic murmurs often have an explanation and that their grade can be useful in the diagnosis and prognosis. They cautioned that a loud systolic murmur did not necessarily indicate a bad prognosis or even serious heart disease. Levine's system of grading a systolic murmur is valuable and persists into the 21st century.

Electrocardiographic-clinical-pathologic sleuthing (by Dr. J. Willis Hurst).

An unusual electrocardiogram was sent to Dr. J. Willis Hurst, who had no knowledge of the clinical details. Afterward, the clinical and laboratory findings were presented for his further comments. In conclusion, the case illustrates how much information can be gathered from just a 12-lead electrocardiogram when analyzed by an 87-year-old expert who continues to teach daily the skills of electrocardiography.

Extracardiac manifestations of infective endocarditis and their historical descriptions.

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. Today, infective endocarditis is most commonly suggested from the history and often clinched by an echocardiogram and blood cultures. Although prized physical manifestations are much less frequent now, they still do occur and may be an invaluable clue that leads to earlier, more effective treatment. The investigators review these extracardiac findings along with their historical descriptions: splinter hemorrhages, emboli, Osler's nodes, Janeway and Bowman lesions of the eye, Roth spots, petechiae, and clubbing.

Discovery of the sinus node by Keith and Flack: on the centennial of their 1907 publication.

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. In 1906, Sunao Tawara found a "complex knoten" of tissue at the proximal end of the His bundle. He concluded that this was the inception of an electrical conducting system which continued from the AV node through the bundle of His, divided into the bundle branches, and terminated as the Purkinje fibres. The collaboration of Arthur Keith and Martin Flack led to discovery of the sinus node, finalising the discovery of the electrical system of the heart and providing an anatomical answer to the baffling mystery: "Why does the heart beat?"

Why does the heart beat? The discovery of the electrical system of the heart.

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. By examining serial embryologic sections, Wilhelm His, Jr, showed that a connective tissue sheet became a bundle connecting the upper and lower cardiac chambers, the bundle of His. Sunao Tawara traced the atrioventricular (AV) bundle of His backward to find a compact node of fibers at the base of the atrial septum and forward where it connected with the bundles of cells discovered by Purkinje in 1839. Tawara concluded that this "AV connecting system" originated in the AV node, penetrated the septum as the His bundle, and then divided into left and right bundle branches that terminated in the Purkinje fibers. Martin Flack and Arthur Keith studied the conduction system of a mole and found a structure in the sinoauricular junction that histologically resembled the AV node. They felt that this was where "the dominating rhythm of the heart normally begins" and named it the sinoauricular node in 1907. The ECG of Einthoven soon brought a new understanding to the complex electrical system that makes the heart beat. In 2006 and 2007, we celebrate the 100th anniversaries of the publication of the exciting discovery of the AV and sinus nodes, truly landmarks in our understanding of cardiac structure and physiology.

A unique case of pulmonary artery leiomyosarcoma.

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". Local thrombolysis was tried without any obvious success. At this point, the possibility of neoplasm was entertained. A cardiac MRI showed a nonhomogeneous mass in the proximal pulmonary artery. Successful surgery was performed, and histological examination of the resected mass was consistent with leiomyosarcoma. A follow-up cardiac MRI showed no residual mass. The dilemma associated with diagnosing pulmonary artery leiomyosarcomas will be discussed.

History and personal observations of electrical cardioversion of atrial fibrillation.

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.