Noninvasive evaluation of normal and abnormal prosthetic valve function.

Noninvasive techniques are helpful in evaluating the function of mechanical prostheses and tissue valves. Combined phonocardiography and M-mode echocardiography together with cinefluoroscopy are the most useful noninvasive techniques in differentiating normal from abnormal metallic prosthetic valve function. The intensity of the opening and closing clicks and associated murmurs will depend on the type of prosthetic valve, the heart rate and rhythm and the underlying hemodynamic status. Arrhythmias or conduction disturbances, or both, may produce motion patterns that mimic some of the echocardiographic signs of malfunctioning prosthetic valves. Differentiation of thrombus formation or tissue ingrowth from paravalvular regurgitation or dehiscence is possible by noninvasive techniques. Disc variance, a potentially serious and lethal problem with the older Beall valves, can be readily detected by cinefluoroscopy and echophonocardiography. With regard to bioprosthetic valves, two-dimensional echocardiography is superior to M-mode echocardiography in detecting primary valve failure. In addition, detection of vegetations, valve alignment and ring and individual leaflet motion can be best accomplished by two-dimensional echocardiography. Of greater importance is the patient serving as his or her own control in the follow-up assessment of prosthetic valve function by noninvasive techniques.

Reliability of bedside evaluation in determining left ventricular function: correlation with left ventricular ejection fraction determined by radionuclide ventriculography.

Ninety-nine patients with chronic coronary artery disease were prospectively evaluated to determine the reliability of historical, physical, electrocardiographic and radiologic data in predicting left ventricular ejection fraction. The left ventricular ejection fraction measured by radionuclide angiography was normal (greater than or equal to 50%) in 44 patients (group 1) and abnormal (less than 50%) in 55 patients; 36 of those 55 patients had an ejection fraction between 30 and 49% (group 2) and the remaining 19 patients had an ejection fraction of less than 30% (group 3). The ejection fraction was correctly predicted in 33 of the 44 patients (75%) in group 1 and in 47 of the 55 patients (85%) with abnormal ejection fraction (groups 2 and 3), but the degree of ventricular dysfunction was correctly predicted in only 19 patients (53%) in group 2 and in only 9 patients (47%) in group 3. Stepwise linear regression analysis was performed. The single most predictive variable was cardiomegaly as seen on chest roentgenography (R2 = 0.52). Four optimal predictive variables--cardiomegaly, myocardial infarction as seen on electrocardiography, dyspnea and rales--could explain only 61% of the observed variables in left ventricular ejection fraction. Thus, radionuclide ventriculography adds significantly to the discriminant power of the clinical, radiographic and electrocardiographic characterization of ventricular function in patients with chronic coronary heart disease.

Value of left ventricular ejection fraction during exercise in predicting the extent of coronary artery disease.

To determine the relation between left ventricular performance during exercise and the extent of coronary artery disease, the results of exercise radionuclide ventriculography were analyzed in 65 patients who also underwent cardiac catheterization. A scoring system was used to quantitate the extent of coronary artery disease. This system takes into account the number and site of stenoses of the major coronary vessels and their secondary branches. The conventional method of interpreting the coronary angiograms indicated that 26 patients had significant coronary artery disease (defined as 70% or more narrowing of luminal diameter) of one vessel, 21 had multivessel disease and 18 had no significant coronary artery disease. Although the exercise left ventricular ejection fraction was significantly higher in patients with no coronary artery disease than in patients with one or multivessel disease (probability [p] less than 0.001), there was considerable overlap among the three groups. With the scoring system, a good correlation was found between the coronary artery disease score and the exercise left ventricular ejection fraction (r = -0.70; p less than 0.001). If the exercise heart rate was 130 beats/min or greater or the age of the patient was 50 years or less, an even better correlation was found (r = -0.73 and r = -0.82, respectively). The exercise ejection fraction (but not the change in ejection fraction, end-diastolic volume and end-systolic volume from rest to exercise) correlated with the extent of coronary artery disease. The exercise ejection fraction is the most important exercise variable that correlates with the extent of coronary artery disease when the latter is assessed quantitatively by a scoring system rather than the conventional method of reporting coronary angiograms. Young age and greater exercise heart rate strengthened the correlation. The change in ejection fraction from rest to exercise is useful in the diagnosis of coronary artery disease, but it was the absolute level of exercise ejection fraction that predicted the extent of disease.

Evaluation of left ventricular function by radionuclide angiography during exercise in normal subjects and in patients with chronic coronary heart disease.

Radionuclide angiography permits evaluation of left ventricular performance during exercise. There are several factors that may affect the results in normal subjects and in patients with chronic coronary heart disease. Important among these are the selection criteria: age, sex, level of exercise, exercise end points, ejection fraction at rest and effects of pharmacologic agents. An abnormal ejection fraction response to exercise is not a specific marker for coronary heart disease but may be encountered in other cardiac diseases. In addition to the diagnostic considerations, important prognostic data can be obtained. Further studies are needed to determine the prognostic implications of anatomic findings versus the functional abnormalities induced by exercise in patients with coronary artery disease.

Tricuspid regurgitation: noninvasive techniques for determining causes and severity.

Tricuspid regurgitation is often not apparent on physical examination and several methods are now available to aid in this difficult assessment. Cardiac catheterization using right ventriculography, previously considered the diagnostic standard, has several limitations. Currently available noninvasive tools such as M-mode and two-dimensional echocardiography (with or without contrast), Doppler techniques and even radionuclide cardiologic imaging have added significantly to the precise assessment of the presence and severity of tricuspid regurgitation. This review examines the comparative use and limitations of these various techniques.

Effect of collateral vessels on prognosis in patients with one vessel coronary artery disease.

The prognostic implications of coronary collateral channels were examined in 359 medically treated patients with one vessel coronary artery disease and a normal left ventricular ejection fraction (greater than or equal to 50%). There were 149 patients with isolated left anterior descending coronary artery disease (group I) and 210 patients with isolated left circumflex or right coronary artery disease (group II). Collateral channels were present in 68 patients (46%) in group I and 115 patients (55%) in group II. During a follow-up period of up to 82 months (mean +/- SD 34 +/- 18), there were 23 cardiac events (4 patients died of cardiac causes and 19 patients had a nonfatal acute myocardial infarction). Actuarial survival analysis showed that the risk of cardiac events was not related to the presence of collateral channels in the two groups. Thus, the risk of cardiac events is not related to the presence or absence of collateral channels in patients with one vessel coronary artery disease. Further, the risks of cardiac death (0.3%/yr) and nonfatal myocardial infarction (1.9%/yr) are very low in medically treated patients with one vessel coronary artery disease and a normal left ventricular ejection fraction.

Thallium 201 myocardial scintigraphy. Advantages and limitations.

Myocardial scintigraphy with thallium 201 is a simple, safe, and valuable noninvasive technique in evaluating the condition of patients with cardiac disorders. Images obtained at rest appear to have limited usefulness at the present time. However, rest imaging may prove to have advantages in the future for early diagnosis of myocardial infarction, thus aiding in the selection of patients to be admitted to the coronary care unit. Exercise imaging, on the other hand, has a high degree of sensitivity and specificity in detecting ischemic heart disease; when combined with treadmill exercise testing, imaging improves the diagnostic accuracy even further.

Exercise thallium 201 imaging. Clinical implications of normal exercise images.

To determine whether normal exercise images can reduce the need for coronary arteriography, we analyzed our data on 102 patients with normal thallium 201 exercise images who underwent coronary arteriographic studies. Eight-two patients had normal or insignificant coronary artery disease; 20 patients had significant coronary artery disease. Eight patients had disease limited to one of the secondary branches of the left system; seven patients had disease limited to one of the major coronary arteries; two patients had disease involving the right coronary artery and a secondary branch; two patients had disease involving two secondary branches; and one patient had disease involving the three major vessels. Seven of the 20 patients had abnormal exercise ECGs, and the remaining 13 patients had normal or inconclusive exercise ECGs. Our findings indicate that significant coronary artery disease is rare in patients with normal exercise images, especially if patients with abnormal exercise ECGs are excluded. Thus, normal exercise images could possibly reduce the need for coronary arteriography, since in these patients coronary artery disease rarely requires bypass surgery.

Asymptomatic myocardial ischemia.

In the vast majority of patients, angina pectoris is the cornerstone on which the diagnosis and treatment of coronary heart disease are formulated. There is evidence to suggest that transient myocardial ischemia may occur without angina pectoris; such episodes are generally detected during ECG or hemodynamic monitoring. The exact incidence, pathophysiologic nature, and importance of asymptomatic myocardial ischemia is not well known and needs further study.

Echocardiographic diagnosis of acute aortic valve endocarditis and its complications.

Staphylococcus aureus aortic valve endocarditis and its complications in a patient were readily recognized by echocardiography. "Shaggy" echoes recorded from the aortic leaflets in diastole as well as irregular diastolic densities in the left ventricular outflow tract suggested flail aortic leaflets secondary to bacterial endocarditis. The presence of a double echo of the anterior aortic wall was an unusual finding. Initially thought to represent a localized dissection, abscess formation and pocket of edematous fluid accumulation was found between the anterior aortic wall and pulmonary artery. Premature closure of the mitral valve was evident shortly before the patient died. The specific echocardiographic features of flail aortic leaflets and premature mitral valve closure should alert the physician to consider immediate aortic valve replacement.

Survival of patients with aortic valve endocarditis. The prognostic implications of the echocardiogram.

The clinical and prognostic implications of the echocardiogram were assessed in 32 patients with clinical aortic valve endocarditis. Seventeen patients had an echocardiographic diagnosis of a vegetation, a flail cusp, or a root abscess (group 1). Ten group 1 patients had embolic episodes. Eight group 1 patients were treated surgically and all survived, while nine group 1 patients were treated medically and two survived. Eleven patients had echocardiographic aortic valve sclerosis (group 2). One group 2 patient had an embolic episode. Six group 2 patients were treated surgically and four survived, while five group 2 patients were treated medically and three survived. Four patients had normal aortic valve echograms (group 3). One group 3 patient had an embolic episode. All group 3 patients were treated medically and survived.

Total occlusion of left main coronary artery without angina pectoris.

A patient had total occlusion of the left main coronary artery that was proved by coronary arteriography. The patient was initially seen with clinical signs of congestive heart failure but without symptoms of angina pectoris or ECG evidence of myocardial infarction. The patient's extensive right-to-left coronary artery collaterals may have contributed to the absence of chest pain. Because of the severe left ventricular dysfunction and the absence of chest pain, the patient was treated with medical therapy. Six months after the cardiac catheterization, he was alive and well under New York Heart Association functional classification II.

Mitral annular calcification. Clinical and echocardiographic correlations.

Clinical, echocardiographic, and radiographic findings in 41 patients with mital annular calcification are presented. Clinical diagnosis included rheumatic heart disease (32%), noninflammatory calcific disease (34%), and chronic renal failure (32%). Mitral annular calcification is recognized echocardiographically as a dense echo band beneath the posterior mitral leaflet with motion paralleling that of the free left ventricular wall. Only two patients of 41 (5%) with mitral annular calcification had calcification on routine x-ray films, and six of 16 (38%) on cinefluoroscopy. The left atrial size is enlarged, and the mitral leaflets are thickened, with reduced motion (D-E) in rheumatic heart disease, but the leaflet motion is well preserved in the nonrheumatic patients. The association of mitral annular calcification with idiopathic hypertrophic subaortic stenosis, chronic renal failure, and bacterial endocarditis is discussed. Echocardiography appears to be a sensitive method of detecting mitral annular calcification and may be helpful in differentiating rheumatic and nonrheumatic etiologies.

Role of exercise thallium 201 imaging in decision making.

This prospective study examined the impact of results of exercise thallium 201 imaging on the estimation of probability of coronary artery disease (CAD) and patient management among cardiologists and internists in our institution. Before exercise testing, the probability of CAD in the 100 patients enrolled in this study was considered low in 31, intermediate in 28, and high in 41 patients. The probability of CAD after exercise thallium imaging was different in four patients (10%) in the high group, 22 patients (79%) in the intermediate group, and three patients (10%) in the low group. Further, the results of exercise testing resulted in changes in patient management in 29 patients (71%) in the high group, 26 patients (93%) in the intermediate group, and 16 patients (52%) in the low group. Overall, the management changed in 71% of the patients. This change included changes in medications, physical activity, frequency of office visits, need for cardiac catheterization, and need for coronary arterial bypass grafting. Thus, exercise thallium imaging is useful in clinical decision making: the diagnostic certainty is improved in patients with intermediate pretest probability of CAD; and some degree of change in patient management is observed, even in patients in whom the probability of CAD is not altered.

Intravenous nitroglycerin for rest angina. Potential pathophysiologic mechanisms of action.

Twenty patients with refractory rest angina pectoris were treated with intravenously (IV) administered nitroglycerin (mean dosage, 72.4 micrograms/min; range, 15 to 226 micrograms/min). There was a considerable reduction or abolition in the number of ischemic episodes in 85% of patients without overall substantial changes in heart rate, mean arterial BP, pulmonary capillary wedge pressure (PCWP), and pulmonary arterial mean pressure. However, those patients with an initial PCWP of more than 12 mm Hg or a systolic pressure of more than 130 mm Hg had a substantial reduction in PCWP and systolic BP following IV nitroglycerin. We conclude that IV nitroglycerin may relieve rest angina by different pathophysiologic mechanisms. In some patients, IV nitroglycerin favorably altered the hemodynamic determinants of myocardial oxygen consumption. In others, however, no change in these determinants occurred, suggesting a direct effect on the coronary circulation.

The contraction of stunned myocardium: isovolumetric bulging and wasted ejection shortening in dog heart.

OBJECTIVE: The aim of the study was to assess the contraction of myocardium stunned by repetitive brief coronary occlusions by examining the response to alterations in loading and inotropy of systolic contraction on isovolumetric and ejection phase shortening. METHODS: Fourteen open chest anaesthetised dogs were used for the studies. After destruction of the sinus node, the heart was atrially paced and atrial extrasystoles were introduced followed by a short (400 ms) or long (700 ms) postextrasystole. The left anterior descending coronary artery was occluded for 5 min and reperfused for 10 min a total of eight times to produce stunned myocardium, followed by a final 60 min of reflow. Regional function was assessed with segment length sonomicrometers. RESULTS: With successive periods of occlusion there was an increase in the end diastolic segment length and a progressive decrease in total percent systolic shortening (baseline 22.3%, 1st reflow 14.5%, 8th reflow 7.9%) with some recovery after 60 min of reflow (12.0%). This was predominantly due to the development of bulging during isovolumetric systole (4.5%, -4.9%, and -8.3%, respectively) which diminished during 60 min recovery to -3.1%. Ejection shortening was relatively constant (17.8%, 19.4%, 16.3%, and 15.1%, respectively). Postextrasystolic potentiation resulted in an increased in total percent systolic shortening, but not to the baseline value, as slight isovolumetric bulging persisted. Similar changes were seen with the short and long postextrasystoles although the latter had a greater increase in ejection shortening. CONCLUSIONS: The decrease in function after repetitive occlusion and reflow is predominantly due to bulging during isovolumetric systole which persists after postextrasystolic potentiation in our model of stunned myocardium.

Value of exercise thallium-201 imaging in patients with diagnostic and nondiagnostic exercise electrocardiograms.

The role of exercise imaging with thallium-201 in the evaluation of patients suspected of having coronary artery disease was studied in 194 patients undergoing diagnostic coronary arteriography. Ninety-eight patients had 70 percent or more narrowing of one or more coronary vessels and 96 patients had either no or insignificant coronary artery disease. One hundren twenty-three of the 194 patients had conclusive treadmill exercise electrocardiograms (either positive or negative), and 71 had inconclusive exercise electrocardiograms. Fifty-four of the 98 patients with coronary artery disease were receiving propranolol at the time of testing. Forty-five (83 percent) of the 54 patients receiving propranolol and 33 (75 percent) of the 44 patients not receiving propranolol had abnormal exercise thallium images (difference not significant). In patients with conclusive exercise electrocardiograms the sensitivity of exercise imaging was not significantly different from that of exercise electrocardiograms (80 versus 74 percent), but the sensitivity of both tests combined (92 percent) was higher than that of either test alone (p less than 0.01). The specificity of exercise imaging (97 percent) electrocardiograms the sensitivity of exercise imaging was not significantly different from that of exercise electrocardiograms (80 versus 74 percent), but the sensitivity of both tests combined (92 percent) was higher than that of either test alone (p less than 0.01). The specificity of exercise imaging (97 percent) electrocardiograms the sensitivity of exercise imaging was not significantly different from that of exercise electrocardiograms (80 versus 74 percent), but the sensitivity of both tests combined (92 percent) was higher than that of either test alone (p less than 0.01). The specificity of exercise imaging (97 percent) was higher than that of exercise electrocardiograms (86 percent, p less than 0.02). The specificity of both tests combined was not significantly different from that of exercise electrocardiograms alone. The sensitivity (79 percent) and specificity (95 percent) of exercise imaging were not significantly different in patients with inconclusive exercise electrocardiograms when compared with those in patients whose exercise electrocardiograms were conclusive. These data indicate that exercise imaging is sensitive and specific in diagnosing coronary artery disease in the presence of diagnostic as well as nondiagnostic exercise electrocardiograms and that propranolol therapy does not affect the results.

Use of exercise thallium-201 imaging for risk stratification of elderly patients with coronary artery disease.

Although coronary artery disease (CAD) may be asymptomatic, it is the most common cause of death in elderly patients in the U.S. This study examined the prognosis of 449 patients with a mean age of 65 years using exercise thallium-201 imaging. At a follow-up of 25 months, 45 patients underwent coronary artery revascularization, 8 died of cardiac causes and 10 had nonfatal acute myocardial infarctions (AMIs). Thus the total of patients with "hard" events was 18. The events included 12 of 276 patients with atypical or non-anginal symptoms versus 6 of 128 with typical angina (p = not significant); 7 of 51 patients (14%) with Q-wave AMI versus 11 of 353 (3%) without Q-wave AMI (p less than 0.001); 1 of 183 patients (1%) with normal versus 17 of 221 (8%) with abnormal exercise thallium-201 images (p less than 0.002); 10 of 76 patients (13%) with multi vessel thallium-201 abnormality vs 8 of 328 (2%) with no or 1-vessel thallium-201 abnormality (p less than 0.001) and 10 of 96 patients (10%) with greater than or equal to 3 abnormal segments by thallium-201 imaging (total segments = 9) versus 8 of 308 patients with no or less than 3 abnormal segments (p less than 0.001). The number of segments with thallium-201 defects was 1 +/- 2 patients without and 3 +/- 2 in patients with hard events (p less than 0.002).(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of two-dimensional and M-mode echocardiography in the evaluation of patients with infective endocarditis.

M-mode and two-dimensional echocardiographic evaluation of infectious endocarditis and its complications was reviewed. In 21 consecutive patients with clinical endocarditis, 22 valves were involved (12 aortic, 5 mitral and 5 tricuspid). M-mode echocardiography detected vegetations in 10 patients (four aortic, two mitral and four tricuspid) and detected complications of endocarditis in 2 patients (one aortic root abscess and one flail aortic cusp). Two-dimensional echocardiography detected vegetations in 9 patients (four aortic, one mitral and four tricuspid) and detected complications in ten patients (five flail aortic cusps, one aortic root abscess, one sinus on Valsalva aneurysm, two flail mitral leaflets and one flail tricuspid valve). Thus, although M-mode and two-dimensional echocardiography had a similar ability to detect actual vegetations, two-dimensional echocardiography was superior to M-mode echocardiography in diagnosing complications of the destructive process.

Two dimensional echocardiographic recognition of the descending thoracic aorta.

Two dimensional echocardiography was used to identify the descending thoracic aorta in 106 subjects. In 12 of these subjects, contrast injection techniques were used to identify this structure as it descended posteriorly adjacent to the atrioventricular groove. The course of the descending thoracic aorta was mapped using both the long axis and transverse axis views. The normal descending thoracic aorta (26 subjects) measured 10 +/- 1.4 mm/m2 during diastole. Unusual M mode echocardiographic patterns of the descending aorta may be confused with other disease states; they are clarified with the two dimensional study. The size and appearance of the descending aorta in different types of cardiovascular disease, including aortic aneurysm, in 80 patients are described. It is anticipated that two dimensional echocardiography will prove to be a useful method of studying patients with aortic disease.