Smoking high-nicotine cigarettes caused a significant increase in systolic and diastolic arterial pressure, heart rate, left ventricular end-diastolic pressure, and coronary sinus, arterial, and venous CO levels, no significant change in left ventricular dp/dt, aortic systolic ejection period, and cardiac index, and a significant decrease in stroke index and coronary sinus, arterial, and venous P02 levels in eight anginal patients with documented coronary disease. One week later, these patients inhaled 150 ppm of carbon monoxide until their increase in coronary sinus CO was similar to that produced after smoking their third cigarette. Inhaling carbon monoxide caused a significant increase in left ventricular end-diastolic pressure and coronary sinus, arterial, and venous CO levels, no significant change in systolic and diastolic arterial pressure, heart rate, and systolic ejection period, and a significant decrease in left ventricular dp/dt, stroke index, cardiac index, and coronary sinus, arterial, and venous PO2 levels. Nicotine caused the increased systolic and diastolic arterial pressure and heart rate after smoking. Carbon monoxide caused the negative inotropic effect which increased the left ventricular end-diastolic pressure and decreased the stroke index after smoking.

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Twenty-five years ago Sir Thomas Lewis summarized the state of knowledge regarding this important congenital lesion (34)* and thought that "new records of cases can have little value unless they reveal new features of interest and importance to the study of the condition." Yet hardly more than a decade later the first patients with coarctation of the aorta were to be successfully operated upon in Sweden (11) and the United States (23). A new era of progress in the treatment and understanding of the pathological physiology of this lesion began. By 1953 Gross had operated on 270 patients (24), and more recently it has been possible to collect data on 1601 patients surgically treated by 36 surgeons (52). It is apparent that operative intervention for coarctation of the aorta has become widely practised. Its broad acceptance appears to be justified not only by the demonstration that the classical pulse abnormalities can be largely reversed (5a, b), but also by the reasonable safety of the procedure and by the subjective improvement of patients (7,8, 24).The cure of the characteristic hypertension has been included among the benefits of surgical treatment in reports from a number of clinics (6,10,20, 24,27,35). Indeed a fall in blood pressure does usually follow successful intervention, but most communications have described the condition shortly after the operative procedure, and the criteria for evaluation of the blood pressure response are usually referred to an arbitrary or ideal value. With few exceptions (6, 9, 59) systematic observations at remote intervals after treatment have not been made, and in one of these (9) the conclusions appear to be at variance with the more numerous and optimistic results reported just after operation. In this latter work alone were the data given careful statistical treatment.Obviously this question is of prognostic importance since the complications of hypertension are the cause of a quarter of the deaths in coarctation (24), and since in untreated cases there is a progressive increase in systolic pressure during the first two decades of life (6). Moreover, the issue is of interest from the theoretical point of view since the mechanism of most forms of hypertension is poorly understood, and that of coarctation has evoked considerable disagreement. The classical view that it is caused by the mechanical obstruction (3, 4,34) has been challenged on a number of grounds by those who hold that it is caused by an interference with the renal arterial flow producing a generalized increase in peripheral resistance (38,44,45). Finally, there has been speculation about the mechanism and significance of the abdominal pain and the paradoxical rise of blood pressure that not infrequently follow resection of the coarctation (2,43, 47). These considerations suggested that an immediate and long-term study of the effect of operation on coarctation hypertension would be desirable. MATERIALS AND METHODSIn the ten years, [1948][1949][1950][1951][1952][1953][1954][1955][1956][1957][1958] 80 patients ...

The functional and structural characteristics of a discrete myocardial segment at the base of the turtle ventricle were studied. The study indicates that this segment is a homologue of the primitive bulbus cordis. Cinematographic techniques were utilized to observe the function of this segment. It contracts later than the main ventricular chamber and acts as a sphincter at the base of the pulmonary artery in late systole. It is suggested that this mechanism serves to regulate the normal left-to-right shunt into the lungs through the incomplete ventricular septum and to maintain adequate systemic blood flow. A resemblance between the arrangement in the turtle and that seen in certain cases of human congenital heart disease is briefly discussed.

Forty-two patients with pure mitral stenosis underwent a prospective, longitudinal study with two or more cardiac catheterizations 1 to 10 years apart and without intervening surgical treatment. The majority of patients had not previously had mitral valve surgery; in 16, the period of observation followed valvotomy. Twenty-seven patients showed evidence of progressive obstruction of the mitral valve; 15 showed no change in the calculated mitral valve area. In the group of patients with progressive disease (stenosis or restenosis) there was a consistent clinical and hemodynamic deterioration: 25 of the 27 showed increasing disability. In the nonprogressive group, seven of the 15 showed increasing symptomatology, most often related to the development of atrial fibrillation and a fall in cardiac output. Possible causes for the different course of mitral stenosis in the two groups are reviewed. The probability that trauma due to altered flow patterns through a stenotic valve produces progressive stenosis is suggested.