Normality index of ventricular contraction based on a statistical model from FADS.

Radionuclide-based imaging is an alternative to evaluate ventricular function and synchrony and may be used as a tool for the identification of patients that could benefit from cardiac resynchronization therapy (CRT). In a previous work, we used Factor Analysis of Dynamic Structures (FADS) to analyze the contribution and spatial distribution of the 3 most significant factors (3-MSF) present in a dynamic series of equilibrium radionuclide angiography images. In this work, a probability density function model of the 3-MSF extracted from FADS for a control group is presented; also an index, based on the likelihood between the control group's contraction model and a sample of normal subjects is proposed. This normality index was compared with those computed for two cardiopathic populations, satisfying the clinical criteria to be considered as candidates for a CRT. The proposed normality index provides a measure, consistent with the phase analysis currently used in clinical environment, sensitive enough to show contraction differences between normal and abnormal groups, which suggests that it can be related to the degree of severity in the ventricular contraction dyssynchrony, and therefore shows promise as a follow-up procedure for patients under CRT.

Cardiovascular medicine at face value: a qualitative pilot study on clinical axiology.

INTRODUCTION: Cardiology is characterized by its state-of-the-art biomedical technology and the predominance of Evidence-Based Medicine. This predominance makes it difficult for healthcare professionals to deal with the ethical dilemmas that emerge in this subspecialty. This paper is a first endeavor to empirically investigate the axiological foundations of the healthcare professionals in a cardiology hospital. Our pilot study selected, as the target population, cardiology personnel not only because of their difficult ethical deliberations but also because of the stringent conditions in which they have to make them. Therefore, there is an urgent need to reconsider clinical ethics and Value-Based Medicine. This study proposes a qualitative analysis of the values and the virtues of healthcare professionals in a cardiology hospital in order to establish how the former impact upon the medical and ethical decisions made by the latter. RESULTS: We point out the need for strengthening the roles of healthcare personnel as educators and guidance counselors in order to meet the ends of medicine, as well as the need for an ethical discernment that is compatible with our results, namely, that the ethical values developed by healthcare professionals stem from their life history as well as their professional education. CONCLUSION: We establish the kind of actions, communication skills and empathy that are required to build a stronger patient-healthcare professional relationship, which at the same time improves prognosis, treatment efficiency and therapeutic adhesion.

[Cost-effectiveness of stress-only myocardial perfusion single photon emission computed tomography (SPECT) imaging]. / Evaluación de la perfusión miocárdica con tomografía computarizada por emisión de fotones individuales (SPECT) cardíaco: utilidad del protocolo sólo-estrés.

UNLABELLED: Single photon emission computed tomography (SPECT) myocardial perfusion imaging is widely used for diagnosing coronary artery disease (CAD). However, SPECT costs, imaging time, and radiation exposure, limit SPECT indications. OBJECTIVE: Determine whether a stress-only SPECT imaging would be enough to obtain a diagnosis of CAD improving nuclear laboratory efficiency. METHODS: 122 patients with unknown CAD were evaluated with stress-only SPECT imaging. In order to evaluate diagnostic accuracy and the prognostic value of the stress-only protocol, patients with abnormal SPECT underwent invasive angiography and patients with normal SPECT were followed-up during 3 years. RESULTS: Diagnosis time, SPECT cost, and radiopharmaceutical dosage were significantly lower as compared with the conventional SPECT imaging protocol (30, 40 and 55%, respectively). Diagnostic accuracy and cardiac prognosis information were comparable to those obtained with the conventional imaging protocol (positive predictive value for CAD of 85% and negative predictive value for cardiac events of 97%). CONCLUSIONS: In patients with intermediate risk for CAD, stress-only SPECT imaging will significantly improve nuclear laboratory efficiency, and with similar accuracy than that the one obtained with the conventional protocol.

[Importance of the heart-brain binomial in the management of congenital heart disease]. / Importancia del binomio corazón-cerebro en el manejo integral de las cardiopatías congénitas.

A case of a two month infant with complex congenital heart disease (aortic coarctation with ventricular septal defect) associated to a cellular brain migration failure is presented. The management strategy consisted on the correction of congenital heart disease by means of a two-stage surgery without a further preoperative evaluation of the neurological status. The patient developed several perioperative complications such as two episodes of cardiac arrest, reconnection to cardiopulmonary bypass, cardiac tamponade, chilothorax and septic shock. A neurological protocol consisting in electroencephalography, brain magnetic resonance and Single Photon Emission Computed Tomography (SPECT) was practiced during the postoperative period, which detected microgyria with paquigyria and a cellular brain migration failure was suspected. The final outcome was death due to multisystemic failure and the autopsy confirmed the neurological disease, as well as poor life function prognosis. Should the heart-brain binomial had been considered in an integral preoperative evaluation, the therapeutical approach could have been modified.

Importancia del binomio corazón-cerebro en el manejo integral de las cardiopatías congénitas / Importance of the heart-brain binomial in the management of congenital heart disease

Se presenta el caso de un lactante de dos meses con una cardiopatía congénita compleja del tipo coartación aórtica con comunicación interventricular asociada a un trastorno de migración celular cerebral. El manejo consistió en la corrección de la cardiopatía congénita en dos tiempos quirúrgicos sin haber profundizado en la evaluación neurológica preoperatoria. El paciente desarrolló múltiples complicaciones perioperatorias que incluyeron paro cardiaco en dos ocasiones, reconexiones consecutivas a circulación extracorpórea, tamponamiento cardiaco, quilotórax y choque séptico. Concomitante a las complicaciones postoperatorias, se realizó una evaluación neurológica secundaria bajo un protocolo de abordaje neurológico que consistió en electroencefalografía, resonancia nuclear magnética y tomografía por emisión de positrón (SPECT). De esta forma se detectó paquigiria con microgiria y se sospechó trastorno de migración celular cerebral. La evolución final fue hacia el deceso por falla multisistémica y la autopsia confirmó la patología neural, así como el pobre pronóstico para la función y la vida. De haberse considerado en el preoperatorio un estudio integral que incluyera el binomio corazón-cerebro, el planteamiento terapéutico podría haberse modificado.

A case of a two month infant with complex congenital heart disease (aortic coarctation with ventricular septal defect) associated to a cellular brain migration failure is presented. The management strategy consisted on the correction of congenital heart disease by means of a two-stage surgery without a further preoperative evaluation of the neurological status. The patient developed several perioperative complications such as two episodes of cardiac arrest, reconnection to cardiopulmonary bypass, cardiac tamponade, chilothorax and septic shock. A neurological protocol consisting in electroencephalography, brain magnetic resonance and Single Photon Emission Computed Tomography (SPECT) was practiced during the postoperative period, which detected microgyria with paquigyria and a cellular brain migration failure was suspected. The final outcome was death due to multisystemic failure and the autopsy confirmed the neurological disease, as well as poor life function prognosis. Should the heart-brain binomial had been considered in an integral preoperative evaluation, the therapeutical approach could have been modified.

Evaluation of ventricular synchrony with equilibrium radionuclide angiography: assessment of variability and accuracy.

BACKGROUND AND AIMS: Equilibrium radionuclide angiography (ERNA) has become an established method for assessing cardiac function. However, limited data are available to evaluate ventricular synchrony with ERNA. The aim of this study was to assess the variability and accuracy of ERNA to evaluate ventricular synchrony by means of phase images in healthy individuals and to compare them with a group of subjects with left bundle-branch block (interventricular dyssynchrony, LBBB) and with a group of patients with nonischemic, dilated cardiomyopathy (DCM) (inter- and intraventricular dyssynchrony). METHODS: The population was divided into groups as follows: group 1 included 22 healthy subjects, group 2 included 11 patients with LBBB and normal left ventricular ejection fraction (LVEF), and group 3 included 14 DCM patients with LVEF <35% and LBBB. Interventricular synchrony was measured as the difference between LV mean phase angle (mPA) and RV mPA (LV-RV mPA). Intraventricular synchrony for each ventricle was measured as the standard deviation (SD) of the RV mPA and LA mPA blood pools. RESULTS: Intra- and interobserver correlation coefficients were high for both inter- and intraventricular synchrony parameters. Area under the curve (AUC) was 0.98 for LV-RV mPA (p <0.001; 95% CI: 0.947-1.0). A cutoff value of 10 degrees yielded 96% sensitivity and 99% specificity to identify interventricular dyssynchrony. AUC was high for SD RV mPA and SD LV mPA (AUC = 1.0, p <0.001; 95% CI: 1.0-1.0 and AUC = 0.99, p <0.001; 95% CI: 0.979-1.0). A cutoff value of 22 degrees for SD LV mPA yielded 100% sensitivity and 100% specificity to identify LV intraventricular dyssynchrony. A cutoff value of 20 degrees for SD RV mPA yielded 100% sensitivity and 99% specificity to identify RV intraventricular dyssynchrony. CONCLUSIONS: ERNA is an accurate and highly reproducible technique for evaluation of ventricular function and synchrony.

Evaluación de la función y sincronía de la contracción ventricular en pacientes con enfermedad de Chagas en estadio de latencia / Evaluation of the function and ventricular synchrony in patients with latency stage of Chagas' disease

OBJECTIVE: To compare the left ventricular function and the ventricular synchrony in patients with Chagas disease in latency stage respect to a control group. METHODS: We analyze a prospective, comparative, transversal and non randomized study of the left ventricular function (LVF) and the ventricular contraction synchronicity (VCS) in 36 subjects with positive serology for Chagas disease (18 males and 18 females), with mean of 15 +/- 5-years-old. The findings were compared with respect to 23 control volunteers (11 males and 12 females) with mean of 28 +/- 5-years-old. LVF and VCS were evaluated using equilibrium radionuclide angiography images (ERNA). The comparison of both Chagas and control populations was carried out by t Student test for independent samples, considering a statistically significant value of p < 0.05. RESULTS: The parameters of the ventricular function and the ventricular synchronicity in subjects with positive serology for Chagas disease were not statistically different with respect to the parameters of the control group. However, although they have a homogeneous contraction, the mean time of contraction for the right and the left ventricle is statistically smaller with respect to the control group. CONCLUSIONS: In clinically incipient stages of Chagas disease we do not found abnormalities in the ventricular function and the ventricular synchronicity. It's necessary to consider the follow up of the studied populations using indices for the identification of abnormalities of the autonomic nervous system.

[Evaluation of the function and ventricular synchrony in patients with latency stage of Chagas' disease]. / Evaluación de la función y sincronía de la contracción ventricular en pacientes con enfermedad de Chagas en estadio de latencia.

OBJECTIVE: To compare the left ventricular function and the ventricular synchrony in patients with Chagas disease in latency stage respect to a control group. METHODS: We analyze a prospective, comparative, transversal and non randomized study of the left ventricular function (LVF) and the ventricular contraction synchronicity (VCS) in 36 subjects with positive serology for Chagas disease (18 males and 18 females), with mean of 15 +/- 5-years-old. The findings were compared with respect to 23 control volunteers (11 males and 12 females) with mean of 28 +/- 5-years-old. LVF and VCS were evaluated using equilibrium radionuclide angiography images (ERNA). The comparison of both Chagas and control populations was carried out by t Student test for independent samples, considering a statistically significant value of p < 0.05. RESULTS: The parameters of the ventricular function and the ventricular synchronicity in subjects with positive serology for Chagas disease were not statistically different with respect to the parameters of the control group. However, although they have a homogeneous contraction, the mean time of contraction for the right and the left ventricle is statistically smaller with respect to the control group. CONCLUSIONS: In clinically incipient stages of Chagas disease we do not found abnormalities in the ventricular function and the ventricular synchronicity. It's necessary to consider the follow up of the studied populations using indices for the identification of abnormalities of the autonomic nervous system.

Clinical utility of 99mTc-labeled ubiquicidin 29-41 antimicrobial peptide for the scintigraphic detection of mediastinitis after cardiac surgery.

BACKGROUND: Previous studies demonstrated that (99m)Tc-labeled-ubiquicidin 29-41 ((99m)Tc-UBI 29-41) imaging is an accurate method for detection of bacterial infections. This study was conducted to evaluate the clinical use of (99m)Tc-UBI 29-41 for detection of mediastinitis after cardiac surgery. METHODS: Thirteen patients with suspected mediastinitis after cardiac surgery were included. Qualitative and semiquantitative analyses of (99m)Tc-UBI 29-41 images were performed. Mediastinitis was confirmed by bacterial culture. RESULTS: Qualitative analysis correctly identified the infection in 5/6 patients with mediastinitis. For observer 1, there were five true-positive results, six true-negative results, one false-positive result and one false-negative result (sensitivity: 83%, specificity: 85%, positive predictive value: 83%, negative predictive value: 85%, and overall diagnostic accuracy: 84%). For observer 2, there were five true-positive results, five true-negative results, two false-positive results and one false-negative result (sensitivity: 83%, specificity: 71%, positive predictive value: 71%, negative predictive value: 83%, and overall diagnostic accuracy: 76%). Agreement between observers was 0.847 (SE=0.145, p=0.002). Semiquantitative analysis showed a higher mediastinum uptake of the (99m)Tc-UBI 29-41 in patients with mediastinitis than that derived from patients without mediastinitis. Mean uptake of (99m)Tc-UBI 29-41 was 60.4+/-10.3 counts/pixel and 47.4+/-5.5 counts/pixel, respectively (p=0.01). At the threshold value of > or =57 counts/pixel using ROC analysis, the sensitivity, specificity, positive predictive value, negative predictive value and overall diagnostic accuracy for detecting patients with mediastinitis were 83, 100, 100, 87, and 92%, respectively (p=0.02; 95% CI: 0.65-1.10%). CONCLUSIONS: (99m)Tc-UBI 29-41 imaging yielded fast and promising first results for patients with suspected mediastinitis after cardiac surgery and, as such, deserves further investigation.

[Apoptosis detection in cardiovascular diseases through nuclear cardiology SPECT images]. / Detección de apoptosis en enfermedades cardiovasculares mediante las imágenes SPECT de cardiología nuclear.

Apoptosis is a biological process of death or cellular suicide present in all the cells of the metazoans. It maintains the balance between the regeneration of pluripotential cells -or stem cells- and the elimination of cells that have already served their function, of cells that have reproduced in excess, or have been genetically damaged beyond repair. Apoptosis activation in cardiomyocytes is a common problem in a large variety of cardiomyopathies; it has been suggested that it is an important contributor ventricular hypertrophy and to the increase of the infarct size in patients with cardiac failure and cardiovascular disease. Clinical diagnosis of apoptosis is a reality in the medical science, its application in different aspects of cardiology includes from coronary cardiopathy to rhythm alterations. In this sense, the use of the non-invasive imaging, can be very useful for the in vivo detection of this type of cellular death in patients with myocardial necrosis, acute myocardial infarct, acute rejection of cardiac transplantation, myocarditis, intracardial malignant tumours, as well as in cardiotoxicity cases and other cardiomyopathies. Particularly, binding of Tc99m-labeled Annexin V, produces gammagraphic images that allow the identification of apoptotic cells in vivo in SPECT and SestaMiBi systems. In summary, the use of these techniques will be invaluable in the near future for anti-apoptosis therapy and intervention in the routine of the daily Cardiology practice.

Detección de apoptosis en enfermedades cardiovasculares mediante las imágenes SPECT de cardiología nuclear / Apoptosis detection in cardiovascular diseases through nuclear cardiology SPECT images

Apoptosis is a biological process of death or cellular suicide present in all the cells of the metazoans. It maintains the balance between the regeneration of pluripotential cells -or stem cells- and the elimination of cells that have already served their function, of cells that have reproduced in excess, or have been genetically damaged beyond repair. Apoptosis activation in cardiomyocytes is a common problem in a large variety of cardiomyopathies; it has been suggested that it is an important contributor ventricular hypertrophy and to the increase of the infarct size in patients with cardiac failure and cardiovascular disease. Clinical diagnosis of apoptosis is a reality in the medical science, its application in different aspects of cardiology includes from coronary cardiopathy to rhythm alterations. In this sense, the use of the non-invasive imaging, can be very useful for the in vivo detection of this type of cellular death in patients with myocardial necrosis, acute myocardial infarct, acute rejection of cardiac transplantation, myocarditis, intracardial malignant tumours, as well as in cardiotoxicity cases and other cardiomyopathies. Particularly, binding of Tc99m-labeled Annexin V, produces gammagraphic images that allow the identification of apoptotic cells in vivo in SPECT and SestaMiBi systems. In summary, the use of these techniques will be invaluable in the near future for anti-apoptosis therapy and intervention in the routine of the daily Cardiology practice.

Myocardial perfusion and ventricular function assessed by SPECT and Gated-SPECT in end-stage renal disease patients before and after renal transplant.

BACKGROUND: Cardiovascular disease is a major cause of morbidity and mortality in end-stage renal disease (ESRD). Renal transplant is known to improve left ventricle hypertrophy and systolic dysfunction in selected groups of patients. METHODS: We assessed myocardial perfusion, wall motion and functional parameters by single photon emission computed tomography (SPECT) and Gated-SPECT in 30 consecutive ESRD patients with normal coronary angiograms before and after renal transplantation. RESULTS: Uremic cardiomyopathy improved significantly after the transplant. The proportion of patients with angina decreased from 26 to 0%; the frequency of cardiomegaly decreased from 57 to 20% (p <0.01); the frequency of segments with perfusion defects decreased from 42.7 to 10.2% (p <0.001); the proportion of patients with low left ventricular ejection fraction (LVEF) dropped from 53.3 to 20% (p <0.001); and mean LVEF increased from (48.0 +/- 9.7% to 58.2 +/- 8.2%). Similarly, the proportion of segments showing systolic wall thickening, hypokinesia and dyskinesia also decreased significantly after renal transplant (p <0.01). CONCLUSIONS: Uremic cardiomyopathy may be potentially reversible in patients with normal angiographic coronary arteries after renal transplant in a relatively short period of time. SPECT and Gated-SPECT are objective gateway methods to determine myocardial perfusion, hypokinesia, dyskinesia, and functional parameters (left ventricular ejection fraction and systolic wall thickening) and may be useful to establish diagnostic, coronariographic, prognostic, and therapeutic indications.

Myocardial perfusion SPECT imaging in patients with myocardial bridging.

BACKGROUND: Although myocardial perfusion single photon emission computed tomography (SPECT) imaging is widely used to assess myocardial ischemia in patients with known or suspected coronary artery disease, only a few patients with myocardial bridging have been evaluated with nuclear techniques. Furthermore, it has been suggested that dipyridamole stress images might underestimate perfusion defects compared with exercise stress images. This study was done to determine the concordance of exercise stress SPECT images with that obtained by dipyridamole stress SPECT images as a means of detecting ischemia in patients with myocardial bridging. METHODS AND RESULTS: Sixteen consecutive patients with angina and normal arteries but myocardial bridging of the left anterior descending artery underwent rest-exercise stress SPECT imaging. Within 2 weeks after angiograms were obtained, only dipyridamole stress images were repeated. The mean angiographic systolic occlusion within the myocardial bridges was 73% +/- 10%. Overall, the prevalence of an abnormal scan was no different in patients who underwent exercise stress myocardial perfusion imaging (MPI) as compared with patients who underwent dipyridamole stress MPI (14/16 [88%] vs 13/16 [81%], respectively; P = .953). Exercise stress MPI showed a higher stress score than dipyridamole stress MPI, but the difference did not reach statistical significance (7.5 +/- 3.3 vs 6 +/- 2.7, P = .147). The strength of agreement among exercise stress MPI and dipyridamole stress MPI studies was good (kappa = 0.765; 95% CI, 0.318 to 1.211; P < .05). CONCLUSIONS: Cardiac SPECT studies can be used effectively for assessing ischemia in patients with angina and myocardial bridging. The evaluation of myocardial perfusion with dipyridamole stress SPECT imaging showed a good agreement with exercise stress SPECT imaging for the detection of ischemia in this group of patients.

[Chest pain syndrome in normal or non-diagnostic conventional ECG at the emergency service. Assessment with myocardial perfusion (SPECT) and ventricular function (Gated-SPECT)]. / El síndrome de dolor torácico en presencia de ECG convencional normal o no diagnóstico en el Servicio de Emergencia. Evaluación a través de la perfusión miocárdica (SPECT) y de la función ventricular (Gated-SPECT).

The arrival of a patient with chest pain syndrome (precordial) to the emergency represents a diagnostic challenge for the physician. Around 6 million persons are seen each year at the Emergency units in the USA. More than half of the patients are admitted for their cardiac evaluation. Its cardiac origin is confirmed in 10 to 15%, and about 15% of them develop myocardial infarction. However, 5 to 10% of patients are dismissed and develop myocardial infarction during the next 48 h. The diagnosis of the infarct is inadvertent and/or patients is not hospitalized in 2 to 8%. The mortality rate is duplicated in none hospitalized patients. Frequently, a conservative observation conduct and/or diagnostic expectation is taken, with the consequent saturation of the intensive care unit that looses its critical character and avoids quick mobilization of the patient with an increase in costs. The clinical judgment, a meticulous clinical history, and careful physical examination play a key role in the differential diagnosis of the precordial pain syndrome; however, pain can be atypical, absent or manifest as an equivalent of pain, which does not exclude the diagnosis of myocardial infarction or ischemia. Likewise, chest pain in the presence of a normal conventional ECG at rest, non-diagnostic or with minimal variations, does not rule out the possibility of a coronary obstruction and does not mean that the pain is not of coronary origin. Other characteristics of the ECG, such as T wave and ST segment alterations, bundle branch block (BBB), LV hypertrophy, interpretation discrepancies, can pose doubts or mistakes in the diagnosis. Although its diagnostic information is essential, other non-invasive laboratory tests are needed, such as the treadmill stress ECG, serial bioenzymatic markers, and myocardial perfusion scintigraphy (SPECT and Gated-SPECT) at rest or under physical or pharmacologic stress. The advantages and disadvantages of the stress ECG, the echocardiography, magnetic resonance and PET are mentioned. The advantages of the SPECT and Gated-SPECT in the diagnosis and prognosis are: 1) great diagnostic objectivity; 2) high sensitivity and specificity; 3) diagnosis does not depend on evolution time of the ischemia and/or infarction, since SPECT diagnoses the initial primary modifications of ischemia; 4) diagnosis is achieved within the established limit of time, in less than 4 to 6 hours. The designed protocols allow to obtain the diagnosis between 30 min and 1:30 h; 5) assesses the myocardium at risk; 6) stratifies the risk and prognosis; 7) defines the site and 8) the involved coronary artery(les); 9) provides the functional significance of the anatomic obstruction; 10) quantifies the ventricular function, i.e., ejection fraction, systolic and diastolic volumes, systolic thickening, ventricular failure signs; 11) provides three-dimensional visualization of the mobility of the left ventricular wall; 12) diagnoses simultaneously the associated presence of ischemia and/or infarction of the right ventricle; 13) its high negative predictive value allows to dismiss immediately and with a great safety margin those patients in whom SPECT revealed normal perfusion; 14) costs are reduced without adversely compromising the safety of the patients. We describe the algorithm used as guideline for the early diagnosis in the presence or absence of ischemic heart disease in the patient with precordial or chest pain syndrome with normal or non-diagnostic ECG at arrival to the emergency ward. It is necessary to modified the clinical educational patterns and to revaluate the advantages and limitations of the clinical history, physical exploration, as well as of the conventional ECG at rest and other diagnostic methods used specifically in relation to the chest pain syndrome with a normal or non diagnostic conventional ECG. SPECT and Gated-SPECT scintigraphy is considered as the best individual and isolated non-invasive test for the diagnostic solution of the precordial syndrome at the Emergency Unit.

Variability of serial same-day left ventricular ejection fraction using quantitative gated SPECT.

BACKGROUND: The accuracy of quantitative gated single photon emission computed tomography (SPECT) (QGS) and the potential limitations for estimation of left ventricular ejection fraction (LVEF) have been extensively evaluated. However, few studies have focused on the serial variability of QGS. This study was conducted to assess the serial variability of QGS for determination of LVEF between 2 sequential technetium 99m sestamibi-gated SPECT acquisitions at rest in both healthy and unhealthy subjects. METHODS AND RESULTS: The study population consisted of 2 groups: group I included 21 volunteers with a low likelihood of CAD, and group II included 22 consecutive patients with documented CAD. Both groups underwent serial SPECT imaging. The overall correlation between sequential images was high (r = 0.94, SEE = 5.3%), and the mean serial variability of LVEF was 5.15% +/- 3.51%. Serial variability was lower for images with high counts (3.45% +/- 3.23%) than for images with low counts (6.85% +/- 3.77%). The mean serial variability was not different between normal and abnormal high-dose images (3.0% +/- 1.56% vs 3.9% +/- 2.77%). However, mean serial variability for images derived from abnormal low-dose images was significantly greater than that derived from normal low-dose images (9.6% +/- 2.22% vs 3.1% +/- 2.12%, P <.05). CONCLUSIONS: Although QGS is an efficacious method to approximate LVEF values and is extremely valuable for incremental risk stratification of patients with coronary artery disease, it has significant variability in the estimation of LVEF on serial images. This should be taken into account when used for serial evaluation of LVEF.

Viabilidad miocárdiaca. Miocardio aturdido e hibernante. Utilidad de la centellografía miocárdica / Myocardial viability. Stunned and hibernating myocardium. Usefulness of the myocardium scintigraphy

Gran importancia ha adquirido el diagnóstico de viabilidad en la miocardiopatía coronaria con insuficiencia cardiaca debido a los excelentes resultados terapéuticos obtenidos. Por su frecuencia, la identificación de viabilidad, ha adquirido proporciones de problema de salud pública. Se describen las características del miocardio aturdido e hibernante así como los protocolos que se utilizan para demostrar tanto la perfusión, reserva miocárdica y su actividad metabólica, con énfasis en los estudios que utilizan los radiotrazadores Talio-201 y Tc99m-sestamibi.

Myocardial perfusion scintigraphy (spect) in the evaluation of patients in the emergency roo with precordial pain and normal or doubtful ischemic ECG. Study 60 cases

Objetivos: Evaluar la utilidad diagnóstica de la centelleografia de perfusión miocárdica con SPECT y Gated-SPECT (GSPECT), en el diagnóstico del síndrome coronario agudo (SCA) en pacientes con dolor precordial y ECG normal o dudoso, dentro de las 6 horas del último episodio de dolor precordial. Métodos: Sesenta pacientes con estas características fueron incluidos. Se realizó en todos los pacientes estudio de perfusión miocárdica con SPECTy Gated SPECT empleando 2 protocolos distintos. Todos los pacientes fueron sometidos a prueba de estrés farmacológico. En 30 casos se realizó angiografía coronaria. Resultados: La perfusión miocárdica en reposo fue anormal o positiva en 25 pacientes (42 por ciento) y normal o negativa en 35 pacientes (58 por ciento). En estos últimos la perfusión se tornó anormal en 15 pacientes (43 por ciento) bajo la prueba de estrés con dipiridamol, y en 19 (54º/0) la perfusión permaneció normal. Este subgrupo se mantuvo libre de eventos coronarios 12 meses posteriores al alta hospitalaria. En el grupo de 25 pts con perfusión positiva en reposo se diagnosticó infarto agudo del miocardio en 7 pacientes, isquemia en 12 y reversibilidad-inversa en 6. La centelleografia de perfusión miocárdica mostró en la fase de reposo una sensibilidad del 61 por ciento (IC 95 por ciento, 39-74 por ciento) y VPN del 71 por ciento (IC 95 por ciento, 58-82 por ciento). En la fase de estrés, la utilidad de la prueba se incrementa en forma significativa alcanzando una sensibilidad del 97 por ciento (IC 95 por ciento,83-99 por ciento), una especificidad del 79 por ciento (IC 95 por ciento, 57-92 por ciento) y lo más sobresaliente, un VPN del 95 por ciento (IC 95 por ciento, 73 por ciento-99 por ciento). Conclusiones El estudio de perfusión miocárdica tiene una sensibilidad del 97 por ciento para identificar a los pacientes con SCA, dolor precordial y ECG de reposo normal o dudoso. En los pacientes con síndrome coronario agudo con riesgo intermedio o bajo en estas técnicas no invasivas de perfusión miocárdica, se obtiene un alto grado de precisión diagnóstica y seguridad, se reducen los internamientos innecesarios así como los costos

Multiplane Transesophageal Echocardiography with Dobutamine in Patients with Biventricular Inferior Myocardial Infarction.

The purpose of this study was to evaluate the alterations of ventricular wall movement in patients with acute posteroinferior myocardial infarction with extension to right cavities with multiplane transesophageal echocardiography (TEE), as well as the utility of dobutamine with this technique to analyze myocardial viability. Nine men with a mean age of 51 years fulfilled the inclusion criteria. Myocardial TEE was performed in all the men 72 hours after the acute event with long- and short-axis transgastric images of both ventricles under basal conditions and with dobutamine infusions of 5 and 10 µg/kg per minute. Results were compared with myocardial perfusion findings obtained with Tc-99m Sestamibi SPECT. Left ventricular myocardial viability was demonstrated in 28 of 45 altered segments with dobutamine stress myocardial TEE and Tc-99m Sestamibi SPECT. Right ventricular myocardial viability was identified in 27 of 30 altered segments with dobutamine stress myocardial TEE in transgastric short and long axes, and with Tc-99m Sestamibi SPECT in 23 of 25 segments only in short-axis images. Multiplane TEE provided excellent image resolution and better definition of endocardial and epicardial borders, which facilitated detailed evaluation of ventricular segmental wall movement. Infusion of low doses of dobutamine made it possible to identify viable tissue in both ventricles, and results were comparable to those of nuclear medicine.

Utilidad del SPECT (tomografía computada por emisión de fotón único) en la detección de enfermedad aterosclerosa coronaria / The use of spect in the detection of coronary atherosclerotic disease

Objetivos: Establecer la utilidad clínica del SPECT para la detección de enfermedad coronaria en relación a la localización, extensión y severidad de las lesiones angiográficas. Material y métodos: Se estudiaron en forma retrospectiva 216 pacientes, seleccionados al azar, en los que se realizó estudio de perfusión miocárdica con SPECT (T1 201 y/o Tc-99 MIBI) y coronariografía para la valoración de su cardiopatía isquémica. Se determinó la localización del defecto de perfusión (pared anterior, posterior, lateral, septal y apical) y el número de vasos afectados, localización y severidad de las lesiones; considerandose significativas con obstrucción igual o mayor del 60 por ciento. Resultados: Del total de 216 pacientes, 181 (83.8 por ciento) fueron hombres y 35 (16.2 por ciento) mujeres, con edad entre 30 y 82 años y antecedentes de IM en 143 hombres y 23 mujeres. La sensibilidad global del SPECT para la detección de enfermedad de un vaso fue de 94 por ciento, de 96 por ciento para dos vasos y del 100 por ciento para enfermedad trivascular. De manera individual la sensibilidad del SPECT para la detección de enfermedad coronaria fue de 91.6 por ciento para la DA, 100 por ciento para la CD, 92.8 por ciento para la CX y de 100 por ciento para la detección de enfermedad del tronco de la coronaria izquierda, respectivamente. Conclusiones: El estudio de perfusión miocárdica mediante técnica SPECT muestra una alta sensibilidad para el diagnóstico de cardiopatía isquémica. La sensibilidad y especificidad fueron mayores en presencia de enfermedad proximal de la descendente anterior, enfermedad trivascular y del tronco de la coronaria izquierda. Existe correlación entre la localización, número y severidad de las lesiones angiográficas y los defectos de perfusión miocárdica detectados mediante técnica SPECT