Uncomplicated Coronary Artery Disease Research Articles

Geometric and functional abnormalities of the left ventricle with a chronic localized noncontractile area

Thirty-one patients with coronary artery disease, 25 of whom had a chronic localized noncontractile area in the anteroapical region of the left ventricle, were studied at rest by means of left heart catheterization, left cineventriculography and selective coronary arteriography. The left ventricular volume, stroke volume, ejection fraction, left ventricular end-diastolic pressure, cardiac output and the surface area of the noncontractile area were measured. The patients with a noncontractile area were classified in 4 groups according to the size of the noncontractile area relative to the end-diastolic left ventricular surface area. The relative size of the non-contractile area ranged from 5 to 47 percent. Six patients with uncomplicated coronary artery disease comprised the control group. The critical size of the noncontractile area beyond which significant functional derangement occurred appeared to be 20 to 30 percent of the left ventricular internal surface area. The end-diastolic volume increased significantly and the ejection fraction was reduced to less than half of normal when the regional noncontractile area was larger than the critical size. Neither the cardiac output nor the left ventricular end-diastolic pressure correlated closely with size of the noncontractile area. In contrast, the ejection fraction was a more sensitive indicator and correlated well with the extent of regional contraction abnormality. In this study, double vessel disease was most common, followed by single vessel disease. Obstruction of the left anterior descending coronary artery was significant in the formation of anteroapical noncontractile regions.

Left ventricular end-diastolic pressure before and after coronary arteriography: The value of coronary arteriography as a stress test

A study of the left ventricular hemodynamics of 95 subjects in whom coronary cinearteriography was performed demonstrated statistical differences among the mean resting left ventricular end-diastolic pressure of normal subjects, patients with cardiomyopathy, patients with coronary artery disease and patients with coronary artery disease and aneurysm. These values were lowest in the normal subjects ( x ̄ = 8.1 mm Hg ) and in those with hypertrophic cardiomyopathy ( x ̄ = 9.7 mm Hg ), higher in the group with uncomplicated coronary artery disease ( x ̄ = 10.2 mm Hg ) and highest in patients with coronary artery disease and aneurysm ( x ̄ = 12 mm Hg ). The mean resting values appeared to be directly related to the degree of disease of the left ventricle. The largest increase of the left ventricular end-diastolic pressure after coronary arteriography, that is, up to 175 percent of the resting value, was recorded in patients with coronary artery disease ( x ̄ = 17.8 mm Hg ) and in the group with left ventricular aneurysm ( x ̄ = 18.6 mm Hg ). Lesser increments were detected in the control subjects ( x ̄ = 12.6 mm Hg ) and in patients with hypertrophic cardiomyopathy ( x ̄ = 11 mm Hg ). The correlation with left cineventriculography clearly indicates that the greatest increase in left ventricular end-diastolic pressure after selective coronary arteriography occurred in those patients who had the more extensive and severe degrees of left ventricular involvement. The behavior of the left ventricular end-diastolic pressure after selective coronary arteriography may be utilized as an additional and useful test in evaluating the functional state of the left ventricle.

Evaluation of some criteria for the dynamic and postexercise electrocardiogram in diagnosing coronary insufficiency

T HE diagnosis of early, uncomplicated coronary artery disease often poses a problem for the clinician, especially if the clinical history, usually his main basis for diagnosis, is silent or misleading. Consequently, various types of stress tests have been devised to aid in diagnosis. Of the stress tests enhancing the value of the electrocardiogram, the two-step exercise test of Master has, by far, been the most widely accepted and used. However, there has arisen in some quarters a controversy regarding the relative merits of the clinical history and the exercise electrocardiogram in the diagnosis of coronary insufficiency. Those who rely on the clinical history of angina pectoris regard the exercise electrocardiogram as purely confirmatory evidence, to be labeled as “false positive” or “false negative” whenever it disagrees with their clinical impression.’ This stand is upheld despite the two well known facts: that a good number (3870, in one study2) of patients who develop myocardial infarction have no previous symptoms and that the etiology of angina is at times apparently extracardiac. On the other hand, those who place greater faith on the exercise electrocardiogram would label a patient with angina and a negative exercise test as a case of “false angina,” and a patient without angina and a positive exercise test as a case of coronary insufficiency. Master’s own belief in his test is so great that he regards a negative test as practically an exclusion of coronary insufficiency.3,4 There are many who disagree with Master in this belief, for until now, the criteria for a “positive” or a “negative” test have not been satisfactorily resolved. Certainly, Master’s criteria have been subjected to so many criticisms that he has had to revise them several times.3-n The frequent revisions and the many conflicting opinions regarding which criteria are significant have compounded the confusion, to the detriment of the test itself. Long term follow-up studies of subjects who performed the two-step test (a postexercise test) have resolved some disputed points. Thus, ischemic S-T segment depression has been accepted by practically all investigators as indicative of coronary insufficiency. Follow-up studies have revealed that a very high percentage of subjects with such a finding develop frank coronary accidents within five to ten years.12-ls Furthermore, postexercise ischemic S-T segment changes were generally associated with advanced and diffuse occlusive coronary disease.17 However, the significance of the junctional type of S-T depression (J depression) and the reliability of the completely negative test as an assurance of a healthy coronary reserve have not yet been fully established. The morbidity or mortality from coronary disease several years after a postexercise test showing J depression has been shown to be significantly lower than tracings showing ischemic depression, and is still lower in subjects with a completely negative test.12-17 This has convinced many physicians that the J depression and the negative postexercise test practically indicate the absence of coronary insufficiency. But closer scrutiny of the results of these long term follow-up studies, such as those of Mattingly, quoted from Gubner,16 who found 87, 62.5 and 44 per cent