It is known from previous investigations ) that patients with coronary heart disease, previous myocardial infarction, and an enlarged heart may show the usual signs of left ventricular failure with increased pulmonary vascular pressures and a tendency to reduced cardiac output. To our knowledge, no systematic investigations of cardiac output and pressures in the lesser circulation have been made in patients with coronary heart disease and a normal-sized heart, with anginal pain as the main symptom. Nor have any observations been published from the same patients when free from pain and when complaining of pain, either spontaneous or induced by exercise.It is generally believed that the administration of nitro-glycerine leads to a dilatation of coronary vessels. An increase in coronary blood flow subsequent to nitro-glycerine has been demonstrated in animals (Gregg, 1950), and its effect on anginal pain due to coronary heart disease in man has also been attributed to its influence on the coronary blood flow (Wayne and Laplace, 1933;Russek et al., 1955). However, there are no observations by cardiac catheterization on the effect of nitro-glycerine on the left ventricular function and the lesser circulation in man. This research has been designed to fill these apparent gaps.Material and Methods. Twenty-four patients with coronary heart disease have been studied by cardiac catheterization, one of them twice at an interval of a year (observations 8 and 9); 20 had electrocardiographic signs and a history of previous myocardial infarction. In these patients catheterization was performed from one month (in one) to eight years after the last known infarction. The four patients without known infarction all had typical anginal pain and also cardiographic changes of angina on staircase tests.The age of the patients, 3 of whom were women, varied from 45 to 84 years. In 3 (Cases 2, 7, and 24) the blood pressure had been raised but was, as in the others, normal at the time of the investigation. Cases 3 and 7 had diabetes mellitus, Cases 8 and 24 had xanthomatosis, and Case 24 had thrombocytopenia. All had regular sinus rhythm during the investigations.With the patients resting on the table, pressure in the right atrium, pulmonary artery, and pulmonary artery wedge position (pulm. capillary pressure) were recorded. The oxygen consumption was determined by spirometry, using room air. Blood samples were obtained from the pulmonary artery (mixed venous blood) and from a peripheral artery, usually the brachial, by an indwelling needle.The patients were investigated during exercise as well as at rest in 15 instances. The exercise consisted of bicycling in recumbency on an ergometer for at least 5-minutes in 10 cases, but in the other 5 it had to be discontinued after 21 to 4 minutes because of excessive dyspnca or anginal pain. A Statham strain-guage coupled to an AC-DC amplifier and a Brush oscillograph was used for the pressure recordings, and the pressures related to a point 10cm. in front of the patient's back. Manometric (van Sl...
