¿Podría ser útil la resonancia magnética de estrés en pacientes con baja probabilidad de cardiopatía isquémica? / Could stress magnetic resonance imaging be useful in patients with a low probability of ischemic heart disease?

Objetivo: Evaluar la utilidad de la resonancia magnética cardiaca de estrés (RMCE) con adenosina en la detección de cardiopatía isquémica en pacientes con baja probabilidad preprueba. Material y Métodos: Se evaluó la utilidad de la RMCE en una selección de pacientes con baja probabilidad preprueba (riesgo cardiovascular bajo o moderado, dolor torácico atípico o ausencia de cardiopatía isquémica previa) mediante el uso del cociente de probabilidad. Resultados: Se incluyeron 295 pacientes, con un seguimiento de 28 (19-36) meses. Un total de 60 pacientes presentaron un evento. Se observó una mayor utilidad de la RMCE en los pacientes con una probabilidad preprueba baja: dolor torácico atípico (cociente de probabilidad [CP] positivo 8,56), ausencia de cardiopatía isquémica previa (CP positivo 4,85) y riesgo cardiovascular bajo o moderado (CP positivo 3,87). Conclusiones: La RMCE puede ser una técnica útil en el diagnóstico de cardiopatía isquémica en pacientes con baja probabilidad preprueba

Objective: To assess the usefulness of cardiac stress magnetic resonance imaging (MRI) with adenosine in the detection of ischemic heart disease in patients with a low pretest probability of disease. Material and methods: We used the probability ratio to analyze the usefulness of cardiac stress MRI in a selection of patients with a low pretest probability of ischemic heart disease (low or moderate cardiovascular risk, atypical chest pain, or absence of prior ischemic heart disease). Results: We included 295 patients followed up for a median of 28 (19-36) months. A total de 60 patients had an event. Cardiac stress MRI was more useful in patients with a low pretest probability: atypical chest pain (probability ratio [PR] positive 8.56), absence of prior ischemic heart disease (PR positive 4.85), and low or moderate cardiovascular risk (PR positive 3.87). Conclusions: Cardiac stress MRI can be useful in the diagnosis of ischemic heart disease in patients with a low pretest probability

Could stress magnetic resonance imaging be useful in patients with a low probability of ischemic heart disease? / ¿Podría ser útil la resonancia magnética de estrés en pacientes con baja probabilidad de cardiopatía isquémica?

OBJECTIVE: To assess the usefulness of cardiac stress magnetic resonance imaging (MRI) with adenosine in the detection of ischemic heart disease in patients with a low pretest probability of disease. MATERIAL AND METHODS: We used the probability ratio to analyze the usefulness of cardiac stress MRI in a selection of patients with a low pretest probability of ischemic heart disease (low or moderate cardiovascular risk, atypical chest pain, or absence of prior ischemic heart disease). RESULTS: We included 295 patients followed up for a median of 28 (19-36) months. A total de 60 patients had an event. Cardiac stress MRI was more useful in patients with a low pretest probability: atypical chest pain (probability ratio [PR] positive 8.56), absence of prior ischemic heart disease (PR positive 4.85), and low or moderate cardiovascular risk (PR positive 3.87). CONCLUSIONS: Cardiac stress MRI can be useful in the diagnosis of ischemic heart disease in patients with a low pretest probability.

[Patients with vulnerable coronary plaques have higher serum metalloproteinase-1 levels]. / Los pacientes con placas coronarias vulnerables presentan mayores niveles séricos de metaloproteinasa-1.

BACKGROUND: Most acute coronary syndromes are caused by the fracture of a vulnerable atherosclerotic plaque. These plaques are thin cap fibroatheromas, which can only be detected with invasive coronary imaging techniques. It is necessary to find a non-invasive biomarker of these vulnerable plaques in order to identify patients at risk without a coronary angiography. Metalloproteinase-1 is an enzyme involved in extracellular matrix metabolism which has been correlated with the rupture of atherosclerotic plaques. Its serum levels in patients with vulnerable plaques remain unknown. METHODS: Patients with suspected stable coronary artery disease undergoing coronary angiography in our hospital were in-cluded. The coronary arteries were studied with optical coherence tomography to detect vulnerable plaques. Blood samples were taken from a peripheral vein and from the coronary sinus, to assess metalloproteinase-1 levels. RESULTS: Fifty-one patients were included, 13 of whom had at least one vulnerable plaque. There were not significant dif-ferences in clinical characteristics, lipid profile or C reactive protein levels, between patients with or without vulnerable plaques. Patients with vulnerable plaques had significant higher metalloproteinase-1 levels both in peripheral (7330±5541 vs 2894±1783 pg/ml, p=0.025) and coronary sinus serum (6012±3854 vs 2707±1252 pg/ml, p=0.047). CONCLUSIONS: Patients with vulnerable plaques had significantly higher metalloproteinase-1 serum levels. Further studies with clinical follow up are needed to assess the prognostic value of serum metalloproteinase-1.

Los pacientes con placas coronarias vulnerables presentan mayores niveles séricos de metaloproteinada-I / Patients with vulnerable coronary plaques have higher serum metalloproteinase-1 levels

Fundamento: Las placas ateroscleróticas que producen la mayoría de los síndromes coronarios agudos al romperse son los fibroateromas de cápsula fina, denominados placas vulnerables. Éstas pueden ser detectadas únicamente con técnicas invasivas de imagen intracoronaria. Es preciso encontrar un biomarcador no invasivo que permita identificar a los pacientes con estas placas sin necesidad de cateterismo cardiaco. La metaloproteinasa-1 es una enzima involucrada en el metabolismo de la matriz extracelular que ha sido relacionada con la ruptura de las placas ateroscleróticas. Se desconocen sus niveles séricos en pacientes con placas vulnerables. Material y métodos: Se incluyeron pacientes sometidos a cateterismo cardiaco por enfermedad coronaria estable. Se estudiaron las arterias coronarias con tomografía de coherencia óptica para detectar placas vulnerables. Se extrajeron muestras de sangre periférica y del seno coronario para analizar la concentración de metaloproteinasa-1. Resultados: Se incluyeron 51 pacientes. Trece tenían al menos un fibroateroma de cápsula fina. No se encontraron diferencias significativas en las características clínicas, perfil lipídico ni proteína C reactiva entre los pacientes con y sin placas vulnerables. Los pacientes con placas vulnerables presentaron concentraciones significativamente mayores de metaloproteinasa-1, tanto en sangre periférica (7330±5541 vs 2894±1783 pg/ml, p=0,025) como en seno coronario (6012±3854 vs 2707±1252 pg/ml, p=0,047). Conclusiones: Los pacientes con placas vulnerables presentaron niveles séricos significativamente mayores de metaloproteinasa-1. Se requieren estudios con seguimiento clínico para evaluar el valor pronóstico de la metaloproteinasa-1 sérica (AU)

Background: Most acute coronary syndromes are caused by the fracture of a vulnerable atherosclerotic plaque. These plaques are thin cap fibroatheromas, which can only be detected with invasive coronary imaging techniques. It is necessary to find a non-invasive biomarker of these vulnerable plaques in order to identify patients at risk without a coronary angiography. Metalloproteinase-1 is an enzyme involved in extracellular matrix metabolism which has been correlated with the rupture of atherosclerotic plaques. Its serum levels in patients with vulnerable plaques remain unknown. Methods: Patients with suspected stable coronary artery disease undergoing coronary angiography in our hospital were included. The coronary arteries were studied with optical coherence tomography to detect vulnerable plaques. Blood samples were taken from a peripheral vein and from the coronary sinus, to assess metalloproteinase-1 levels. Results: Fifty-one patients were included, 13 of whom had at least one vulnerable plaque. There were not significant differences in clinical characteristics, lipid profile or C reactive protein levels, between patients with or without vulnerable plaques. Patients with vulnerable plaques had significant higher metalloproteinase-1 levels both in peripheral (7330±5541 vs 2894±1783 pg/ml, p=0.025) and coronary sinus serum (6012±3854 vs 2707±1252 pg/ml, p=0.047). Conclusions: Patients with vulnerable plaques had significantly higher metalloproteinase-1 serum levels. Further studies with clinical follow up are needed to assess the prognostic value of serum metalloproteinase-1 (AU)

Recomendaciones sobre las indicaciones clínicas de la gated-SPECT de perfusión miocárdica / Recommendations on Clinical Indications for Myocardial Perfusion Gated SPECT

Desde 1999 no se había realizado ninguna revisión de las Guías de actuación clínica de la Sociedad Española de Cardiología en Cardiología Nuclear, por lo que en este artículo exponemos las indicaciones clase I y IIa de la American College of Cardiology/American Heart Association/American Society of Nuclear Cardiology (ACC/AHA/ASNC) con nivel de evidencia A o B, junto con las 27 indicaciones consideradas adecuadas por el Comité de expertos de la American College of Cardiology Foundation/American Society of Nuclear Cardiology (ACCF/ASNC) y los comentarios que hemos considerado oportuno añadir los firmantes de este artículo

Guidelines on Nuclear Cardiology have not been revised since 1999. Correspondingly, this article describes the class-I and class-IIa indications of the American College of Cardiology (ACC)/American Heart Association (AHA)/American Society for Nuclear Cardiology (ASNC), which have a grade-A or grade-B level of supporting evidence. In addition, details are given of the 27 appropriateness criteria of the American College of Cardiology Foundation (ACCF)/ASNC expert committee, along with additional comments which the authors of this review thought were appropriate to make at this time

Insuficiencia cardíaca. Tratamiento farmacológico actual / Heart failure. Current pharmacologic treatment

El tratamiento de la insuficiencia cardíaca (IC) ha cambiado considerablementeen los últimos años, a pesar de que pocos fármacosnuevos han sido aprobados. El tratamiento actual no sólo va dirigidoa mejorar los síntomas, sino también a prevenir el paso de disfunciónsistólica a IC sintomática, a prevenir el remodelado cardíaco, ladisfunción renal y a reducir la mortalidad.Los grupos de fármacos utilizados actualmente son: digitálicos, diuréticos,inhibidores de la enzima conversora de la angiotensina (IECA),betabloqueantes (BB), inhibidores de los receptores de la angiotensinaII (ARA-II) y antagonistas de los receptores de la aldosterona. Lacombinación de dinitrato de isosorbide + hidralazina apenas se usapor sus efectos secundarios y no existe ningún nuevo inotrópico positivoaprobado en IC crónica, ya que todos han demostrado aumentarla mortalidad. El levosimendán es un inotrópico positivo que seutiliza por vía intravenosa en la IC aguda, con un efecto favorablesobre el pronóstico en comparación con placebo y con dobutamina(que lo empeora).Los fármacos aprobados por vía oral se pueden administrar a la vezsi el paciente los tolera, ya que su efecto beneficioso es aditivo. Lamortalidad en dos años de los pacientes en IC leve-moderada secalcula en un 34% con la combinación de digital + diuréticos. Alañadir IECA baja al 22%; al añadir un BB baja al 14%; al añadir unantagonista de la aldosterona baja al 10%. Los ARA-II pueden darseen vez de IECA o añadirse a todos los demás

Treatment of heart failure (HF) has changed in recent years, despitethe paucity of new approved drugs. Current treatment is directed notonly towards improving symptoms, but also to preventing the developmentfrom asymptomatic systolic dysfunction to symptomatic heartfailure, to preventing cardiac remodelling, renal dysfunction and toreducing mortality.The main families of drugs currently used are: cardiac glycosides,diuretics, angiotensin-converting enzyme inhibitors (ACEI), beta-blockingdrugs (BB), angiotensin-II receptor blockers (ARB) and aldosteronereceptor antagonists. The combination isosorbide dinitrate +hydralazine is hardly used due to its side effects and none of the newpositive inotropic drugs has been approved in chronic HF, because allof them increase mortality. Levosimendan is a new positive inotropicagent approved for acute HF by an intravenous route, with a favourableeffect on prognosis vs placebo and vs dobutamine (which worsensthe prognosis). The approved oral drugs can be given at the sametime if the patient tolerates them, because their beneficial effect isadditive. Mortality in two years in mild to moderate HF is 34% withglycosides + diuretics. It falls to 22% when an ACEI is added, to 14%when a BB is added and to 10% when an aldosterone antagonist isadded. ARB can be given instead of an ACEI or be added to the otherdrugs

[Heart failure. Current pharmacologic treatment]. / Insuficiencia cardiaca. tratamiento farmacológico actual.

Treatment of heart failure (HF) has changed in recent years, despite the paucity of new approved drugs. Current treatment is directed not only towards improving symptoms, but also to preventing the development from asymptomatic systolic dysfunction to symptomatic heart failure, to preventing cardiac remodelling, renal dysfunction and to reducing mortality. The main families of drugs currently used are: cardiac glycosides, diuretics, angiotensin-converting enzyme inhibitors (ACEI), beta-blocking drugs (BB), angiotensin-II receptor blockers (ARB) and aldosterone receptor antagonists. The combination isosorbide dinitrate + hydralazine is hardly used due to its side effects and none of the new positive inotropic drugs has been approved in chronic HF, because all of them increase mortality. Levosimendan is a new positive inotropic agent approved for acute HF by an intravenous route, with a favourable effect on prognosis vs placebo and vs dobutamine (which worsens the prognosis). The approved oral drugs can be given at the same time if the patient tolerates them, because their beneficial effect is additive. Mortality in two years in mild to moderate HF is 34% with glycosides + diuretics. It falls to 22% when an ACEI is added, to 14% when a BB is added and to 10% when an aldosterone antagonist is added. ARB can be given instead of an ACEI or be added to the other drugs.

[Clinical practice guidelines of the Spanish Society of Cardiology on unstable angina/infarction without ST elevation]. / Guías de práctica clínica de la Sociedad Española de Cardiología en la angina inestable/infarto sin elevación ST.

This paper up-dates the Clinical Guidelines for Unstable Angina/Non Q wave Myocardial Infarction of the Spanish Society of Cardiology. Due to the increased efficacy of adequate management in the early phases, it has been considered necessary to include recommendations for the pre Hospital and Emergency department phase. Prehospital management. Patients with thoracic pain compatible with myocardial ischemia should be transferred to Hospital as quickly as possible and an ECG tracing performed. Initial management includes rest, sublingual nitroglycerin and aspirin. In the Emergency department. Immediate clinical attention and accessibility to a defibrillator should be available. If ECG tracing discloses ST elevation reperfusion strategy is to be implemented immediately. If no ST elevation is present, the probability of myocardial ischemia and risk factor evaluation is essential for adequate management. A simplified risk stratification classification is presented, that also determines the most adequate site for admission: Coronary Care Unit if high risk factors are present, Cardiology ward for the intermediate risk patient and ambulatory treatment if low risk. Management in Coronary Care Unit. Includes routine ECG monitoring and analgesia. Antithrombotic and anti ischemic treatment include new indication for GP IIb-IIIa and Low molecular weight heparins. Coronary arteriography and revascularisation are recommended, if refractory or recurrent angina, left ventricles dysfunction or other complications are present. Management in the ward is based on adequate chronic medical treatment, risk stratification, and secondary prevention strategy. Coronary arteriography before discharge must be considered in the light of the result of non-invasive tests.

Clandestine ischemia in patients with vasospastic angina.

BACKGROUND: Coronary vasospasms generally occur at rest, but can also be triggered by physical exercise. Anginal pain and ST-segment elevation may be seen during exercise-stress tests. ST-segment depression, due to nonocclusive vasospasms, has also been found to occur. When the result of a test is positive, scintigraphy usually reveals perfusion defects. True silent or clandestine ischemia (normal result of exercise test with perfusion defects) in these patients is very uncommon. OBJECTIVE: To stress the need for suspecting occurrence of coronary vasospasms in order to perform a proper diagnosis. METHODS: Eight patients with angina were selected for this study. They had negative results of exercise tests with perfusion defects detected by thallium-201 tomography, normal coronary arteries and vasospasms. Maximal exercise-stress tests with thallium-201 tomography were performed. Sizes of perfusion defects were quantified by examining polar maps. Coronary angiography and then an intracoronary ergonovine test were performed for each patient. RESULTS: Significant defects were seen in territory of the right coronary artery, the left anterior descending artery, or both. Lung:heart ratio was normal in every case. The coronary arteries were normal and vasospasms were elicited with ergonovine in all the patients. Correspondence between the location of perfusion defects and angiographic spasms was generally observed. After treatment with calcium antagonists and nitrates all of them improved and defects detected by thallium tomography were no longer found when tests were repeated. CONCLUSIONS: Some patients with vasospastic angina may have normal results of exercise-stress tests and reversible perfusion defects detectable by scintigraphy. This finding must lead one to perform coronary angiography without administration of nitroglycerine beforehand and an ergonovine test if the coronary arteries are normal.

[The clinical management guidelines of the Sociedad Española de Cardiología in acute myocardial infarct]. / Guías de actuación clínica de la Sociedad Española de Cardiología en el infarto agudo de miocardio.

In the recent years, new possibilities have emerged in the diagnosis and management of acute myocardial infarction with ST segment elevation and its complications. Moreover, a deep transformation has taken place in the health care system organization, particularly in aspects related to care of patients presenting non-traumatic chest pain, both in pre-hospital and hospital areas. All these issues warrant a consensus document in Spain dealing with the role that these important changes should play in the whole management of myocardial infarction patients. This document revises and updates all the main clinical issues of acute myocardial infarction patients from the moment they contact with the health care system outside the hospital until they return home, after staying at the coronary care unit and the general hospitalization ward. All those aspects are considered not only in the uncomplicated myocardial infarction but also in the complicated one. This review also includes a set of recommendations on structural and organisational aspects, mainly referred to the prehospital and emergency levels.

[Guidelines of the Spanish Society of Cardiology for cardiopulmonary resuscitation]. / Guías de actuación clínica de la Sociedad Española de Cardiología en resucitación cardiopulmonar.

Cardiac arrest, consistent on cessation of cardiac mechanical activity, is diagnosed in the absence of consciousness, pulse and breath. The totality of measurements applied to revert it is called cardiopulmonary resuscitation. Two different levels can be distinguished: basic vital support and advanced cardiac vital support. In the basic vital support methods which do not require special technology are used: opening of air lines, mouth to mouth ventilation, cardiac massage; recently, there is a tendency to include the use of defibrillator. Advanced cardiac vital support should be the continuation of basic vital support. In this situation defibrillator, venous cannulation, orotracheal intubation, mechanical ventilation with high content in oxygen and drugs are used. Before beginning cardiopulmonary resuscitation, one should make sure that a real cardiac arrest is present, less than 10 min have elapsed, the victim does not have an immediately fatal prognosis and there is no deny by the victim or his/her family to receive cardiopulmonary resuscitation. In case of doubt it should be always practised. It is important to know the diagnosis and prognosis of the cause of cardiac arrest as soon as possible, in order to treat it and decide if the maneuvers should be continued. Hydro-electrolytic disturbances must be treated and neurological damage after cardiopulmonary resuscitation must be assessed. Only 20% of patients who recover an effective cardiac rhythm after cardiopulmonary resuscitation are discharged from hospital without neurological sequelae.

[Changes in the diameter of the coronary arteries in heart transplant recipients with angiographically normal vessels during five years]. / Cambios de diámetro de las arterias coronarias en receptores de transplante cardíaco con vasos angiográficamente normales durante cinco años.

INTRODUCTION: Diffuse or focal coronary artery narrowing is a frequent complication of cardiac transplantation. Coronary enlargement has also been described although it is less known. To study the changes of the coronary arteries in transplant recipients, we have performed a quantitative study throughout 5 years. METHODS: Serial coronary angiography was performed annually in all survivors of heart transplant. Forty four patients with visually normal coronary arteries and at least 5 years of evolution were selected for this study. Quantitative measurements of the diameter of the coronary arteries were performed in each angiogram at different levels: proximal, medium and distal left anterior descending coronary artery; proximal and distal left circumflex; proximal, medium and distal right coronary artery. Changes in diameter were compared throughout the 5 years. RESULTS: In the entire group of patients there was a small increase in the diameter of each segment. Taking each patient separately, an enlargement of the diameter of the proximal descending coronary artery was seen in 17 cases; medium descending coronary artery in 13; distal descending coronary artery in 8; proximal left circumflex in 11; distal left circumflex in 14; proximal right coronary artery in 18; medium right coronary artery in 18 and distal right coronary artery in 15. In total, 114 of 352 coronary segments (32%) underwent dilatation. Only 6 patients failed to have dilatation of any segment. CONCLUSIONS: Enlargement of the coronary arterial diameter was seen in 32% of segments of the main coronary arteries in heart transplant recipients with angiographically normal coronary arteries during 5 years of evolution. This could be due to intimal thickening with overcompensation by an additional vessel enlargement with net lumen gain.

[Changes in the left ventricular function with growing doses of dobutamine in healthy individuals]. / Modificaciones de la función ventricular izquierda con dosis crecientes de dobutamina en individuos sanos.

The study aimed to assess ventricular function in response to increasing doses of dobutamine in healthy young volunteers. Isotopic ventriculography was performed at baseline, low dose (10 microg/Kg/min) and high dose (40 microg/Kg/min) of dobutamine. Global and segmentary ejection fraction, ejection fraction in the first third of systole, peak filling rate and peak filling rate time were analysed. A progressive increase in the global ejection fraction in relation to the increasing doses was observed. The segmentary ejection fraction and ejection fraction in the first third of systole also increased with the low dose, but no significant differences were found between both doses. Concerning the diastolic function, the peak filling rate increased significantly with both doses, with no differences between them. We conclude that dobutamine at these doses leads to an increase in all systolic parameters and in the peak filling rate without changing the peak filling rate time in healthy subjects.

[Thallium-201 uptake in lung and heart with different types of stress. Study in healthy volunteers]. / Captación de Talio-201 en pulmón y corazón con diferentes tipos de estrés. Estudio en voluntarios sanos.

Forty healthy male volunteers, aged 1,7 +/- 0.9 years, were studied to verify any possible differences in lung and heart Thallium-201 uptake with different types of stress. All of them were studied with myocardial perfusion SPECT after the injection of 201Thallium. The 40 individuals were randomized into four groups of 10 subjects and each group was subjected to a different type of stress: physical exercise, dobutamine, dipyridamole and adenosine triphosphate (ATP). Significant differences were observed with regard to lung and heart 201Thallium uptake, both of them being lower with physical exercise than with any of the drugs. However, the lung/heart ratio was equivalent for all the groups. We conclude that, even though physical exercise induces a lower lung and heart 201Thallium uptake than does pharmacological stress, the lung/heart ratio is comparable in the four types of stress and has a value of 0.28 +/- 0.03 in healthy young subjects.

[The first-choice technic for assessing myocardial viability. Cardiac perfusion gammagraphy]. / Técnica de primera elección para la valoración de la viabilidad miocárdica. Gammagrafía cardíaca de perfusión.

Stress echocardiography and perfusion scintigraphy are both useful techniques in the assessment of myocardial viability. The use of one technique or the other as the first choice test depends mainly on each hospital's experience. Perfusion scintigraphy should be chosen as the first technique in the following situations: a) hospitals with little experience in stress echocardiography and a good Nuclear Medicine department; b) patients with a bad acoustic window in rest echocardiography; c) contraindication of a high dobutamine dose, and d) need of quantification of viable area. When having chosen echocardiography as the first technique, perfusion scintigraphy is indicated when the response to dobutamine of the asynergic area does not allow the confirmation or the rejection of the presence of viability.

[Study of myocardial viability using single-photon emission computed tomography with 201-thallium and re-injection in 4 series (early and late images]. / Estudio de la viabilidad miocárdica mediante tomografía de emisión de fotón único con talio-201 y reinyección en 4 series (imágenes precoces y tardías).

OBJECTIVE: The present study was designed to determine whether 24-hour imaging after thallium reinjection or imaging obtained shortly after reinjection provides better results regarding reversibility of fixed perfusion defects observed in conventional stress-redistribution imaging. PATIENTS AND METHODS: We studied 24 patients undergoing stress-redistribution thallium tomography with fixed defects (15 exercise, 6 adenosine, 3 dobutamine). All patients had coronary angiography and 17 a history of myocardial infarction. After obtaining the redistribution images, 1 mCi thallium was injected at rest, and images were acquired at 30 minutes and 24 hours after reinjection. The tomograms obtained were divided into 12 segments and analyzed quantitatively. RESULTS: Of the 190 abnormal segments on the stress images, 53 (28%) demonstrated improved thallium uptake on redistribution images and 137 had persistent defects. Shortly after reinjection, 33 (24%) segments had improved thallium uptake and 104 had persistent defects, 29 (28%) of which showed further improvement in the 24-hour study. In patients with myocardial infarction, of the 36 fixed severe defects, 9 (25%) had improved thallium uptake shortly after reinjection, increasing activity from 36 +/- 10% to 53 +/- 8%, and 22 (61%) defects improved at 24 hours, increasing activity from 37 +/- 8% to 56 +/- 6%. Therefore, 13 irreversible segments in the short-term study after reinjection were reversible on 24-hour images. CONCLUSION: These data indicate that 24-hour imaging after thallium reinjection provides better results regarding reversibility of fixed perfusion defects observed in conventional stress-redistribution imaging than imaging obtained shortly after reinjection.

[Role of noninvasive examinations in the management of ischemic heart disease. III. Assessment of myocardial viability]. / Papel de las exloraciones no invasivas en el manejo de la cardiopatía isquémica. III. Estimación de la viabilidad miocárdica.

Assessment of myocardial viability is a field of growing interest. This article summarizes the pathophysiology of myocardial stunning and hibernation; both phenomena are associated with the presence of dysfunctional, viable myocardium. The techniques that are currently available for the assessment of viability, and the clinical situations in which these assessments may be more useful are discussed.

A new experimental model of isolated myocardial ischemic injury: ECG findings of acute isolated right ventricular ischemic injury.

A new experimental porcine model for creating selective ischemia of a specific part of the myocardium while the rest of the myocardium remains free of ischemia has been used to study the electrocardiographic (ECG) changes deriving from selective ischemia of the right ventricular (RV) free wall. A patch was stitched to the ventricle to produce selective myocardial ischemic injury. In a preliminary study of nine pigs, selective ischemia of the left ventricular free wall in five and of the RV free wall in four animals was induced, and a postmortem dye injection was performed to evaluate blood flow in the area of ischemia. In an ECG study of 20 pigs, the baseline ECG was recorded with use of the standard leads I-III, aVR, aVL, and aVF, left precordial leads (V1-V6), and leads V4R, V3H, and V4H and 1 hour after inducing ischemia, the ECG study was repeated. Our experimental model produced ischemic injury in which the location and surface area were known antemortem. In the 20 pigs, ST-segment changes were recorded in leads V1-V3, V3H, and V4H. In only four pigs (20%) was ST-segment elevation recorded in lead V4R. The results show that the ECG signs of selective ischemia of the RV free wall may imitate the signs of anterior or anterolateral infarction of the left ventricle. In this study, elevation of the ST-segment in lead V4R was not pathognomonic of for RV ischemia. This model is a new tool for studying hemodynamic and ECG changes of selective univentricular or biventricular ischemic injury.