Usefulness of cardiac MRI in the prognosis and follow-up of ischemic heart disease.

Cardiac magnetic resonance imaging (MRI) is an important tool that makes it possible to evaluate patients with cardiovascular disease; in addition to infarction and alterations in myocardial perfusion, cardiac MRI is useful for evaluating other phenomena such as microvascular obstruction and ischemia. The main prognostic factors in cardiac MRI are ventricular dysfunction, necrosis in late enhancement sequences, and ischemia in stress sequences. In acute myocardial infarction, cardiac MRI can evaluate the peri-infarct zone and quantify the size of the infarct. Furthermore, cardiac MRI's ability to detect and evaluate microvascular obstruction makes it a fundamental tool for establishing the prognosis of ischemic heart disease. In patients with chronic ischemic heart disease, cardiac MRI can detect ischemia induced by pharmacological stress and can diagnose infarcts that can be missed on other techniques.

[Evaluation of the left ventricle with three-dimensional echocardiography: comparison with cardiac magnetic resonance]. / Evaluación del ventrículo izquierdo por ecocardiografia tridimensional. Comparación con la Cardio-RM.

OBJECTIVE: Three-dimensional echocardiography (3DE) is becoming increasingly common in clinical environments. However, the quality of the images depends on the acoustic window, and it can be difficult to identify the endocardial borders. The objective of this study was to evaluate the performance of 3DE in determining the volumes and left ventricular ejection fraction in unselected patients against the gold standard, cardiac magnetic resonance (CMR). MATERIAL AND METHODS: In 47 unselected patients who underwent CMR, we performed 3DE using a real-time acquisition technique and semiautomatic border detection. RESULTS: We excluded 4 patients (8.5%) because they had an extremely deficient acoustic window. In the remaining 43 patients, including those with a suboptimal acoustic window, we obtained the following correlations between 3DE and CMR: end-diastolic volume, 0.71; end-systolic volume, 0.77; ejection fraction, 0.74. Although the end-diastolic volume was systematically underestimated, no significant differences were observed in the ejection fraction. When the 11 patients with suboptimal acoustic windows were excluded, we observed a systematic underestimation of the end-diastolic and end-systolic volumes, which paradoxically gave rise to improved correlation coefficients (0.79, 0.92, and 0.84, respectively) and a more accurate ejection fraction. CONCLUSIONS: Compared to CMR, 3DE systematically underestimates the ventricular volumes but enables adequate determination of the left ventricular ejection fraction regardless of the quality of the acoustic window.

High prevalence of myocardial monoclonal antimyosin antibody uptake in patients with chronic idiopathic dilated cardiomyopathy.

Monoclonal antimyosin antibody studies were undertaken to assess the presence of myocardial uptake in patients with chronic idiopathic dilated cardiomyopathy. Three groups were studied: 17 patients with chronic (greater than 12 months) idiopathic dilated cardiomyopathy, 12 patients with a large, poorly contracting left ventricle not due to dilated cardiomyopathy (control patients) and 8 normal individuals. The patients in the cardiomyopathy and control groups showed a similar degree of clinical and functional impairment. Imaging was undertaken 48 h after antimyosin injection. The heart/lung ratio of antimyosin uptake was used to assess the results. The mean ratio in the cardiomyopathy group was 1.83 +/- 0.36 (range 1.40 to 2.80), a value significantly higher than that obtained in the control patients without cardiomyopathy (mean 1.46 +/- 0.04, range 1.38 to 1.50) or normal subjects (mean 1.46 +/- 0.13, range 1.31 to 1.6) (p less than 0.01). No difference in the ratio was noted between the normal subjects and control patients. Abnormal antimyosin uptake was seen in 12 (70%) of the 17 patients with cardiomyopathy and in only 1 (8%) of the 12 control patients. Positive monoclonal antimyosin antibody studies are highly prevalent in chronic idiopathic dilated cardiomyopathy.

Myocardial cell damage in human hypertension.

OBJECTIVES: The goal of this study was to investigate the presence of myocardial cell damage in patients with systemic hypertension and its relationship with left ventricular hypertrophy (LVH). BACKGROUND: Although initially compensatory, LVH adversely affects myocellular integrity and contributes to congestive heart failure in hypertensive patients. Noninvasive detection of myocardial damage can be of value. METHODS: We performed imaging studies with 111In-labeled monoclonal antimyosin antibodies to identify myocardial damage in 39 patients with systemic hypertension and variable degrees of LVH. Three groups were considered: 16 asymptomatic patients with normal echocardiographic left ventricular mass (LVM) (group I); 14 asymptomatic patients with LVH (group II) and 9 patients with symptomatic hypertensive heart disease and advanced LVH (group III). The severity of myocardial damage was represented as heart-to-lung (target-to-background) antibody uptake ratio (normal: <1.55). RESULTS: Mean LVM index was 105+/-14 g/m2 in group I, 124+/-24 in group II and 174+/-29 in group III. Heart-to-lung ratios of antimyosin uptake were: 1.45+/-0.14 in group I, 4 of the 16 (25%) patients showing an abnormal scan; 1.50+/-0.07 in group II with abnormal scans in 2 of the 14 (16%) patients and 1.77+/-0.16 (p < 0.001) in group III, all 9 patients presenting with abnormal antimyosin scans. On multivariate regression analysis LVM index was the main variable that independently correlated with the degree of myocardial uptake of antimyosin (r = 0.815; p = 0.001). CONCLUSIONS: This study provides the first in vivo evidence of myocyte damage in patients with hypertension. The severity of myocardial damage can be related to the magnitude of LVH.

Spectrum of alcohol-induced myocardial damage detected by indium-111-labeled monoclonal antimyosin antibodies.

OBJECTIVES: We sought to determine the prevalence, intensity and evolving changes of myocardial damage detected by myocardial uptake of antimyosin antibodies in patients with alcohol-induced dilated cardiomyopathy, alcohol addicts attending a detoxification unit and healthy subjects with short-term alcohol consumption. BACKGROUND: Evidence of alcohol-induced myocardial damage may be provided by myocardial uptake of indium-111-labeled monoclonal antimyosin antibodies. The spectrum of such damage in patients who are heavy drinkers (> 100 g for > 10 years), with or without cardiomyopathy, and the impact of short-term alcohol ingestion on antimyosin antibody uptake have not been adequately explored. METHODS: One hundred twenty antimyosin studies were performed in 56 patients with dilated cardiomyopathy (group I), 15 alcohol addicts attending a detoxification unit (group II) and 6 volunteers for short-term alcohol ingestion (group III). Estimation of antibody uptake was calculated through a heart/lung ratio (HLR) (normal < 1.55). RESULTS: The 56 patients in group I (54 men, 2 women; mean [+/-SD] age 46 +/- 11 years) had consumed 123 +/- 60 g/day of alcohol for 21 +/- 9 years, for a cumulative intake of 914 +/- 478 kg. Mean duration of symptoms was 46 +/- 49 months. Mean left ventricular end-diastolic diameter was 71 +/- 10 mm, and mean ejection fraction was 28 +/- 12%. No differences in New York Heart Association functional class, ventricular size or ejection fraction were noted between 28 active and 28 past consumers, except for the prevalence and intensity of antibody uptake (75% vs. 32%, p < 0.001) and HLR (1.75 +/- 0.26 vs. 1.49 +/- 0.17, p = 0.0001). In 19 patients in the active group restudied after alcohol withdrawal, antibody uptake decreased (from 1.76 +/- 0.17 to 1.55 +/- 0.19, p < 0.001), and ejection fraction improved (from 30 +/- 12% to 43 +/- 16%, (p < 0.001). No changes occurred in the 15 past consumers restudied. The 15 male patients in group II (mean age 36 +/- 4 years) had consumed 156 +/- 59 g/day for 17 +/- 5 years, for a cumulative alcohol intake of 978 +/- 537 kg, an amount similar to that in patients in group I, but antimyosin antibody uptake was detected in only 3 (20%) of 15 patients. None of six group III subjects developed antibody uptake after short-term ethanol ingestion. Despite the small sample size, the power to detect clinically relevant differences in most variables that did not reach statistical significance was amply sufficient. CONCLUSIONS: In alcohol-induced dilated cardiomyopathy, alcohol withdrawal is associated with the reduction or disappearance of myocardial damage and improvement of function. The difference in prevalence of antimyosin antibody uptake in patients with and without cardiac disease who consume similar amounts of alcohol suggests the presence of those with different myocardial susceptibilities to alcohol. Short-term ethanol ingestion in healthy subjects does not induce detectable uptake of antimyosin antibodies.

Comparison of morphologic assessment of hypertrophic cardiomyopathy by magnetic resonance versus echocardiographic imaging.

To compare the value of echocardiography and magnetic resonance imaging (MRI) in the assessment of the amount and extent of hypertrophy in hypertrophic cardiomyopathy (HC) and, second, to correlate the degree of hypertrophy, as assessed by MRI, with clinical and electrocardiographic parameters, 30 consecutive patients (16 men and 14 women, aged 20 to 74 years) with HC were studied. Measurements of left ventricular wall thickness were performed at 11 predetermined segments (5 basal, 5 midventricular, and 1 apical) by 2-dimensional echocardiography and MRI. Two parameters derived from MRI studies were considered as indicators of the degree and extent of hypertrophy: (1) mean of the measured wall thickness at the 11 segments, and (2) the number of segments with thickness > 15 mm. Results showed that, from a total of 330 myocardial segments, thickness could be measured by echocardiography in 221 (67%), whereas MRI allowed measurement of 320 segments (97%). When compared with clinical and electrocardiographic data, no correlation was found regarding mean wall thickness and number of hypertrophied segments by MRI except for the presence of an abnormal electrocardiographic repolarization pattern. It is concluded that MRI allows a better assessment of the degree and extension of left ventricular hypertrophy than echocardiography in HC. Despite the precise information on hypertrophy provided by MRI, the amount and degree of hypertrophy bears no correlation with most of the clinical data in these patients.

Findings on Doppler echocardiography in asymptomatic intravenous heroin users.

To detect potential cardiac abnormalities induced by intravenous heroin use, 68 persons without a previous episode of infective endocarditis were studied by Doppler echocardiography. A control group of 41 normal subjects was studied for comparison. The following measurements were considered: (1) diameter of heart chambers, (2) systolic left ventricular function, (3) morphologic valvular abnormalities, (4) presence of valve regurgitations, (5) Doppler indexes of diastolic function, and (6) estimation of pulmonary arterial resistances. Results showed no significant differences regarding the size of the heart chambers or systolic left ventricular function. A significantly higher incidence of valvular abnormalities (focal thickening or valve prolapse) was found in drug addicts (p = 0.0009) at the mitral and tricuspid valves, as was valvular regurgitation detected by Doppler (p = 0.04). Also, a significantly prolonged deceleration time of mitral and tricuspid early diastolic Doppler flow was found in the study group (p = 0.0001 and 0.027, respectively) although a different hemodynamic condition in the study group (pharmacologically reduced preload) precluded these findings to be attributable to an actual diastolic dysfunction. No differences were observed in pulmonary arterial resistances. It is concluded that mitral and tricuspid valve abnormalities can be detected by echocardiography in asymptomatic intravenous heroin users, whereas no apparent effects are observed in morphologic or functional parameters of cardiac structures other than the valves.

Pulsed Doppler patterns of left atrial flow in mitral regurgitation.

A prospective pulsed Doppler study of 55 patients was undertaken to detect and quantitate mitral regurgitation. Systolic left atrial flow dispersion indicated mitral regurgitation. Doppler study was feasible in nearly 95% of patients. Sensitivity, specificity and predictive accuracy were 89%, 84% and 88%, respectively. Three methods were used to quantitate mitral regurgitation: (1) maximal depth level of systolic left atrial flow, (2) left atrial flow patterns immediately behind the mitral valve closure line (I, protosystolic; II, gradual decrease in intensity of left atrial flow signal throughout systole; and III, broad flow dispersion occupying all systole); and (3) a score system that combined these 2 methods. Results showed that flow patterns behind the mitral valve closure line correlate with angiographic assessment of mitral regurgitation. This provided the simplest and most practical method of determining the severity of mitral regurgitation.

Doppler-derived gradients in normally functioning Monostrut Björk-Shiley prostheses.

In summary, reference values of Doppler gradients obtained in a large number of patients with normal-functioning mitral and aortic Monostrut Björk-Shiley prostheses are reported. It is shown that the value of the transprosthetic gradient increases with decreasing valve size in patients with aortic prostheses. No individual significant variations of the transprothetic Doppler gradient during a 3-year follow-up were observed.

The Monostrut Björk-Shiley valve. Seven years' experience.

The results of cardiac valve replacement with the Monostrut Björk-Shiley prosthesis (Shiley, Inc., Irvine, Calif.) during a 7-year period are presented. A total of 984 valves were implanted in 820 patients from May 1983 to April 1990. Aortic valve replacement was performed in 378 patients, mitral replacement in 294, and multiple replacement in 148. In addition, 180 patients (22%) underwent associated procedures. Mean age was 52.6 +/- 11 years. Operative (30 days) mortality was 5.9% (49 patients): 3.9% (15 patients) for aortic, 7.8% (23 patients) for mitral, and 7.4% (11 patients) for multiple valve replacement. All patients were given long-term anticoagulation therapy. Follow-up was 99% complete (eight patients were lost to follow-up), with a closing interval of 3 months, and totaled 2422 patient-years. Valve-related complications, expressed as percentage event-free (+/- standard error) at seven years were as follows: structural deterioration, 100%; nonstructural dysfunction, 98.3% +/- 0.6%; thromboembolism, 90.2% +/- 1.7%; anticoagulant-related hemorrhage, 88.7% +/- 2.8%; and prosthetic valve endocarditis, 98.1% +/- 0.8%. There were no cases of valve thrombosis. Actuarial survival (free from operative, valve-related, and sudden death) was 88.4% +/- 1.2% at 7 years. Freedom from reoperation was 96.8% +/- 0.1%. Probability of being free from all valve-related morbidity and mortality was 70% +/- 3%, and 708 (93%) of the survivors were in New York Heart Association class I or II. Serial Doppler echocardiograms were done prospectively in 243 patients (with 154 aortic and 120 mitral prostheses), both postoperatively and at regular intervals up to 3 years. Mean prosthetic gradients ranged from an average of 20.9 to 7 mm Hg in the aortic prostheses (21 to 29 mm) and from 6.1 to 4.8 mm Hg in the mitral prostheses (25 to 31 mm). The gradients in each patient did not change significantly during the follow-up period. Our 7 year's experience with the Monostrut valve shows a low rate of valve-related complications, a durable design, and good hemodynamic and functional results.

An unusual case of bioprosthetic mitral valve thrombosis.

Bioprosthetic valve thrombosis and related embolism are considered extremely unlikely, thus allowing most patients to avoid long-term anticoagulation. There is, however, limited experience in the diagnosis and treatment of such a condition. We present the case of a patient with a porcine mitral bioprosthesis who presented with acute thrombosis with unusual echocardiographic features. A favorable outcome was observed after conventional anticoagulant treatment.

Prospective validation of detection and quantitative assessment of chronic aortic regurgitation by a combined echocardiographic and Doppler method.

To establish the accuracy of Doppler echocardiography in the assessment of chronic aortic regurgitation (AR), 87 patients were included in a two-step prospective study. In a first consecutive series of 56 patients, two-dimensional directed M-mode echocardiography and pulsed wave Doppler (PWD) studies were performed within a 24-hour interval of a conventional contrast aortic angiography, which showed AR in 46 patients. Sensitivity and specificity of PWD in the detection of AR were both 100%. To quantitate AR, a left ventricular outflow tract (LVOT) PWD mapping was scored. Significant differences between 1, 2, and 3 to 4 angiographic grades of AR were obtained. As some overlap existed between groups, a multifactorial analysis of PWD and echocardiographic measurements was performed: optimal discrimination was obtained when a new score combining LVOT mapping by PWD, diastolic left ventricular diameter, and aortic root dimension was considered. A prospective validation of this combined echocardiographic-Doppler method was then applied on a second group of 31 catheterized patients with AR. Correlation obtained (r = 0.86; p less than 0.001) confirmed the accuracy of this new method in the prediction of the severity of AR.

Usefulness of the I/D angiotensin-converting enzyme genotype for detecting the risk of left ventricular hypertrophy in pharmacologically treated hypertensive men.

The insertion/deletion polymorphism (I/D) of the angiotensin-converting enzyme (ACE) gene has been associated in some studies with a higher prevalence of left ventricular hypertrophy (LVH), but few of them were performed on pharmacologically treated hypertensive patients. The present study was undertaken to determine whether ACE genotype determination could help in the identification of pharmacologically treated hypertensive patients at a higher risk of LVH. Ninety-six consecutive men with essential hypertension were selected for the study. Left ventricular mass (LVM) was assessed by echocardiography and indexed by body surface area and 82 patients were considered suitable for the study. Three groups of patients were defined on the basis of their I/D ACE genotype: DD (n = 39), ID (n = 33) and II (n = 10). There were no statistically significant differences between the three groups regarding to the severity of hypertension at diagnosis, degree of control of blood pressure or type of antihypertensive drug therapy used. No statistically significant differences were found between the three groups regarding to LVM index (total 124 +/- 31, DD 121 +/- 29, ID 127 +/- 35 and II 122 +/- 18 g/m2), relative wall thickness (total 0.5 +/- 0. 2, DD 0.5 +/- 0.3, ID 0.48 +/- 0.07 and II 0.47 +/- 0.04) or prevalence of LVH (total 34%, DD 31%, ID 39% and II 30% by Cornell criteria and total 39%, DD 33%, ID 45% and II 40% by Framingham criteria). Furthermore, the I and D allele frequency distribution was similar in the whole group of patients, in patients with LVH, and in a control group of healthy volunteers. Our data do not support that the I/D ACE genotype determination helps in identifying treated hypertensive patients at higher risk of LVH. Journal of Human Hypertension (2000) 14, 327-331

Reversal of dilated cardiomyopathy after chronic tricyclic antidepressant drug withdrawal.

Two patients referred for heart transplantation for dilated cardiomyopathy on chronic tricyclic antidepressant treatment are described. Echocardiographic normalization of left ventricular diameters and function were evidenced after drug withdrawal, suggesting drug-induced toxic myocardial disease. The possibility of functional improvement after tricyclic antidepressant drug withdrawal should be kept in mind before including patients with dilated cardiomyopathy in a heart transplantation program.

Dopamine treatment of locally procured donor hearts: relevance on postoperative cardiac histology and function.

UNLABELLED: Administration of catecholamines can lead to myocyte damage. Dopamine treatment is often used in potential cardiac donors to attain hemodynamic stability. Donor hearts exposed to dopamine are rejected or selected for transplantation without clearly defined criteria. A prospective study was undertaken to analyze the clinical relevance of dopamine-induced myocardial lesions in 25 hearts (21 male, 4 female; 15-40 years, mean: 26 +/- 7) that were later used for transplantation. Donors were divided into those who had received dopamine and those who had not. Dopamine doses ranged from 2-12.5 micrograms/kg/min (mean: 6.3 +/- 3). Time of administration was 3-26 hours (mean: 16 +/- 8). Use of dopamine was unrelated to donor electrocardiographic findings, intra- or postoperative death, or difficulty coming off by-pass. Postoperatively, filling pressures were similar in both groups of patients at 2 and 10 days postoperatively. Left ventricular ejection fraction was similar in the two groups. Dopamine requirements were significantly higher in the dopamine-treated hearts (P = 0.05). Histologic findings at first biopsy revealed infiltration and cell damage in a similar proportion of patients in both groups. IN CONCLUSION: donor hearts exposed to dopamine can be accepted for transplantation if doses ranging from 2-12.5 micrograms/kg/min have been administered up to 24 hours.

The 20 mm Medtronic Hall prosthesis in the small aortic root.

BACKGROUND AND AIMS OF THE STUDY: The choice of prosthesis becomes crucial in the narrow aortic annulus. The 20 mm Medtronic Hall valve has a reduced sewing ring that fits in an annulus where only a 19 mm valve would fit. This study assesses the hemodynamic performance of this prosthesis at rest and at exercise, and compares it with two 19 mm mechanical prostheses. MATERIALS AND METHODS: Forty-two patients were studied by Doppler echocardiography, a mean of 34 months following surgery. Twenty-six had a 19 mm prosthesis implanted (12 standard St. Jude Medical and 14 Monostrut valves) and 16 had a 20 mm Medtronic Hall. Parameters studied were peak velocity and transvalvular gradient, both at rest and at exercise, effective orifice area and valve index. RESULTS: No differences were found between the two 19 mm valves, but when compared with the Medtronic Hall valve at rest, this valve showed significantly lower peak velocity and gradient (2.9 vs. 3.3 m/sec, p < 0.01, and 17 vs. 23 mmHg, p < 0.003, respectively) and higher effective orifice area and valve index (1.3 vs. 1.0 cm2, p < 0.01 and 0.81 vs. 0.62 cm2, p < 0.006, respectively). There were also significant differences under exercise. CONCLUSIONS: The 20 mm Medtronic Hall prosthesis shows a significantly better hemodynamic performance, both at rest and under exercise, than other, 19 mm mechanical prostheses and represents a superior choice in valve replacement with a small aortic root.

Pulsed Doppler assessment of tricuspid regurgitation: usefulness of regurgitant signal patterns for estimation of severity.

A study on the value of pulsed Doppler in the detection and quantitative assessment of tricuspid regurgitation (TR) has been conducted on 33 consecutive adult patients with valvular heart disease. Only 1 patient had to be excluded owing to a technically inadequate Doppler examination. Data for comparison were obtained from a right heart catheterization performed within a twenty-four-hour interval from the Doppler study. Sensitivity and specificity in the detection of the lesion were 88% and 100%, respectively. A previously undescribed pulsed Doppler method for the estimation of the degree of TR was tested, based on the consideration of two distinctive patterns of the regurgitant Doppler signal: type I: a protosystolic regurgitant signal with progressively fading intensity along systole; and type II: a homogeneously intense pansystolic signal. Correlation between these patterns and the angiographic degrees of TR showed that milder lesions correspond to the type I Doppler pattern, whereas significant regurgitations present a type II pattern, this allowing a clinically useful method of assessment of TR.

[Intraoperative transesophageal echocardiography: initial experience with 60 patients]. / Ecocardiografía transesofágica intraoperatoria: experiencia inicial en 60 pacientes.

To assess the usefulness of intraoperative transesophageal echocardiography (ITE), this technique was applied in 60 non-selected cardiac patients operated on in our hospital by the surgical team. Only one case was excluded because it was not possible to introduce the probe, and no complications were observed in any patient. ITE permitted: 1) to obtain images without interruption and with no interference with the surgeons or anesthesiologists; 2) to confirm the preoperative diagnosis; 3) to facilitate the surgical approach; 4) the monitoring of left ventricular function, and 5) to evaluate the immediate results of the surgical procedures, particularly the assessment by Doppler technique of residual valvular regurgitations after valve repair. A minor but not disdainable inconvenience of ITE relates to the strategy of its application, as it requires a completely dedicated equipment and operator in the surgical area.

[Acute myocardial infarct studied by magnetic resonance with gadolinium-DTPA contrast compared to echocardiography]. / Estudio del infarto agudo de miocardio mediante resonancia magnética de contraste con gadolinio-DTPA en comparación con la ecocardiografía.

INTRODUCTION AND OBJECTIVES: Gadolinium-DTPA used as a contrast agent in magnetic resonance imaging allows the detection and quantification of the necrotic area in acute myocardial infarction. The aim of the present study is to assess the value of this method for the diagnosis of myocardial infarction in comparison with clinical and echocardiographic data. METHODS: Contrast magnetic resonance imaging and echocardiographic studies were performed on 16 patients during the first week after admission for acute myocardial infarction. Necrotic and total myocardial mass were calculated from magnetic resonance images and this was compared to the extension of the myocardial infarction assessed by electrocardiography and the peak level of total creatinine-phosphokinase serum enzyme. The number and localization of myocardial segments showing contrast uptake was related to segments with contractile abnormalities at the echocardiographic exam. RESULTS: The mean value of the mass of myocardial necrosis calculated from the total area of gadolinium-DTPA uptake in each patient was 25 g (range: 2-67 g), corresponding to 17% of the total myocardial mass (range: 1-45%). This value correlated with the peak serum level of total creatinine-phosphokinase enzyme (r = 0.714; p < 0.003) and with the number of Q waves present at the electrocardiogram (r = 0.69; p < 0.005). A very good agreement between the location of the myocardial infarction by ECG, echocardiography and magnetic resonance was evidenced, and a satisfactory correlation existed between myocardial segments with gadolinium-DTPA uptake and akinetic echocardiographic segments (kappa = 0.65). CONCLUSIONS: The detection and quantitation of the necrotic area in the acute myocardial infarction with gadolinium-DTPA contrast magnetic resonance shows a good correlation with clinical and echocardiographic data.

[Current state of non-invasive methods in the study of coronary arteries and surgical bypass grafts]. / Estado actual del estudio de las arterias coronarias y los injertos quirúrgicos por métodos no invasivos.

The advantages of visualizing the coronary arteries by means of a non-invasive technique as an alternative to conventional angiography are obvious. Echocardiography and computed tomography have not proved to be useful in this application. Magnetic resonance imaging, however, has recently been reported as a method able to depict reliable images of the coronary vessels, including the visualization of stenotic lesions. Unfortunately, these preliminary data have not yet been followed by studies confirming the usefulness of the technique in practice, probably because of the complexity of the current magnetic resonance imaging methods and, also, to the difficulties that the intricate coronary arterial tree poses to a tomographic imaging method such as magnetic resonance imaging. On the other hand, in particular aspects of the spectrum of coronary diseases, as anomalous congenital origin of the vessels or assessment of patency of venous bypass grafts, magnetic resonance imaging has proved to be of value and may be considered a useful diagnostic tool in clinical practice.