Myocardial necrosis by electrocution: evaluation of noninvasive methods.

We present the case of a young man who suffered severe anteroapical myocardial necrosis caused by electrocution. In addition to the enzymatic and electrocardiographic changes suggesting necrosis, a clear positive segmental image on 99mTc-pyrophosphate scintigraphy and a defect on a 201Tl SPECT scan at rest were also found. Although these tests were indicative of extensive anteroapical transmural myocardial necrosis, the echocardiographic study only revealed mild anteroapical hypokinesia.

Comparison of patients with anterior wall healed myocardial infarction with and without exercise-induced ST-segment elevation.

To assess the extent of myocardial necrosis and ischemia in patients with anterior wall healed myocardial infarction depending on whether ST-segment elevation was present on precordial leads during exercise testing, 62 consecutive patients (49 men and 13 women, age [mean +/- SD] 56 +/- 11 years) with anterior wall infarcts were assessed with exercise technetium-99m (Tc-99m) methoxy-isobutyl-isonitrile single-photon emission computed tomography and quantification of the extent of necrosis and ischemia on polar maps: 22 patients had > or = 1 mm ST-segment elevation during exercise, and 40 did not. The extent of the necrosis in the anteroseptal (p = 0.001) and apical (p = 0.002) regions, the extent of ischemia in the lateral region (p = 0.003) on polar maps, and the frequency of ventricular aneurysm as shown by cardiac catheterization (p = 0.001) were significantly greater in patients with ST-segment elevation. In a multiple logistic regression model, both extent of necrosis in the anteroseptal region (odds ratio 10.8; 95% confidence interval 2.7 to 44.0) and extent of ischemia in the lateral region (odds ratio 7.25; 95% confidence interval 1.6 to 32.7) were associated with exercise-induced ST-segment elevation. These data suggest that ST-segment elevation in anterior infarctions is associated with wider necrosis in the anteroseptal and apical regions, with a wider extent of ischemia in the lateral region and a higher frequency of ventricular aneurysm. Consequently, it cannot be used as a marker of viability.

[Evaluation of DDD and VVIR pacemakers with gated radionuclide ventriculography]. / Valoración del marcapasos DDD y VVIR mediante la técnica de la ventriculografía isotópica en equilibrio.

Gated radionuclide ventriculography was performed in 53 patients, with 29 DDD and 24 VVIR pacemakers. Ejection fraction and regional contractility was studied in three conditions: a) At rest. b) With tachycardia after exercise. And c) With induced tachycardia at rest. At a rate similar to the one reached with the exercise. Stimulation in different parts of the right ventricule did not show any differences in the ejection fraction. Induced ventricular stimulation in comparison with natural ventricular contractions did not alter or change ejection fraction if the reached rate was the same an not too high in both cases. Induced stimulation at rest with a rate of 110-120/min, decreased the ejection fraction in 10% (p less than 0.001). Induced stimulation by exercise (VVIR. DDD) increased the ejection fraction in 10% (p less than 0.003) and if there were zones of dyskinesia they improved or disappeared. There were no statistical differences between VVIR and DDD pacemakers. It seems that a limited tachycardia is convenient for patients with rate response pacemakers (VVIR).

[Myocardial contractility and viability. A radionuclide tomography study using technetium-99m labeled isonitriles]. / Contractilidad y viabilidad miocárdicas. Estudio mediante tomogammagrafía con isonitrilos marcados con tecnecio-99m.

BACKGROUND: There are comparatively few studies evaluating the patterns of myocardial viability and its relation with contractility in patients with coronary artery disease. The aim of the present study was to quantify the viable and nonviable myocardium, using 99m-technetium isonitriles SPET, as related with left ventricular regional wall motion abnormalities. METHOD: 61 consecutive patients with coronary artery disease were investigated. The severity and extension of the defects were evaluated using a qualitative and quantitative analysis of the 99mTc-isonitriles SPET and compared with ventricular wall motion in contrast ventriculography. An uptake level of 40% of peak uptake or higher was considered as indicating viable myocardium. RESULTS: Of the 244 evaluated regions (4 per patient), 72 (29%) had normal perfusion, 100 (41%) were ischemic, 25 (10%) had a mild irreversible defect and 47 (19%) had a severe irreversible defect. Wall motion was normal in 176 regions (72%), 29 (12%) were hypokinetic, and 39 (16%) were akinetic of dyskinetic. The amount of viable myocardium in akinetic and dyskinetic regions (64.8%) was significantly different (p < 0.05) from that in hypokinetic (86.1%) and normokinetic (98.8%) regions. Visual assessment of uptake underestimated myocardial viability, as quantitative analysis disclosed that in 61% of akinetic and dyskinetic regions with severe irreversible defects there was more than 50% of viable myocardium. CONCLUSIONS: In 61% of akinetic and dyskinetic regions with a severe irreversible defect in perfusion scintigraphy positive viability criteria were found. Therefore, visual assessment of the myocardial perfusion studies using 99mTc-MIBI SPET underestimates viable myocardium. Tomographic studies with quantification of the uptake and defect extension are required for a proper evaluation of viable myocardium.

[Quantification of left-to-right shunt in atrial septal defect using oximetry, isotopes, and Doppler echocardiography. Is there a method of reference?]. / Cuantificación del cortocircuito de la comunicación interauricular mediante oximetría, isótopos y ecocardiografía Doppler. Existe un método de referencia?

INTRODUCTION: Determination of pulmonary to systemic blood flow ratio (QP/QS) is considered to be important for the management of patients with atrial septal defect. The QP/QS provides information on shunt severity and is usually determined by three methods: oximetry, first-pass radionuclide angiocardiography and Doppler echocardiography. The aim of the present study was to assess the accuracy and concordance level of these three methods in QP/QS quantification in atrial septal defects. PATIENTS AND METHODS: Sixty-four adult atrial septal defects patients in whom QP/QS was determined by these three methods with a 6 month interval were studied. Nuclear and echocardiographic post-surgical studies were repeated in 36 patients. RESULTS: QP/QS values determined by the three techniques had a low correlation between them: oximetry (r = 0.52; SEE = 0.74); radionuclide angiocardiography (r = 0.40; SEE = 0.79) and Doppler echocardiography (r = 0.72; SEE = 0.57). Radionuclide angiocardiography underestimated QP/QS > 3 (-0.61 +/- 1.21; p < 0.01). Only in 33% of studies there concordance (differences < 0.5) among the three methods and in 58% between two methods. Right ventricular dilatation and tricuspid regurgitation influenced radionuclide accuracy. Nevertheless, the correlation between this technique and echocardiography was satisfactory when the 36 post-surgical were included (r = 0.75); both techniques agreed in the diagnosis of the two cases with residual post-surgical shunt. CONCLUSIONS: Inter-method disparity in QP/QS quantification is high and no method can be used as a gold standard; clinical decisions therefore based on QP/QS quantification by one technique alone are ill-advised.

[Prognosis of patients with angina pectoris or silent ischemia: exercise 99mTC-MIBI SPECT]. / Pronóstico de los pacientes con angina y con isquemia silente en la tomogammagrafía de esfuerzo con 99mTc-MIBI.

INTRODUCTION AND OBJECTIVES: Although different reports have compared the extent of the myocardial ischemia in patients with or without angina during exercise test, there have been few publications which have studied their prognosis. The aim of this study is to analyze the prognostic value of the presence of angina during 99mTc-MIBI SPECT in patients with proven coronary artery disease without previous myocardial infarction. PATIENTS AND METHODS: We studied 82 patients prospectively with at least one coronary stenosis > 70% and with reversible perfusion defects in 99mTc-MIBI SPECT (long protocol). Twenty two of these patients had angina during exercise test. The extension of ischemia was quantified on SPECT and the severity of coronary stenoses on coronary angiography. The mean follow-up period was 3.2 years. RESULTS: The angina patients showed a significantly lower coronary reserve (exercise duration: 6.3 min vs 8 min; p = 0.03), a lower maximal O2 consumption (5.8 METs vs 6.2 METs; p = 0.04), a higher rate of ST depression > 1 mm (64% vs 19%; p = 0.006) and a higher degree of ST depression (0.9 mm vs 0.4 mm; p = 0.01) than those patients without angina. There were no significant differences in the extent of ischemia in SPECT or in the angiographic severity of coronary disease between either groups. During the follow-up period the presence of severe complications (myocardial infarction or death) tended to be higher (27% vs 17%; NS) in patients with angina and the indication of surgical revascularization was also significantly higher (50% vs 17%; p = 0.002) in this group. CONCLUSIONS: Presence of angina during 99mTc-MIBI SPECT portends a higher risk of medium and long term complications, mainly due to surgical revascularization.

[Subtraction scintigraphy with thallium-201 chloride and technetium-99m pertechnetate versus high resolution ultrasonography in the localization of the parathyroid glands in primary hyperparathyroidism]. / Gammagrafía de sustracción con cloruro de talio-201 y pertecnetato de tecnecio-99m frente a la ultrasonografía de alta resolución en la localización de las glándulas paratiroides en el hiperparatiroidismo primario.

BACKGROUND: The aim of this study was to evaluate the use of scintigraphy with thallium-201 chloride (201 Tl) and technetium-99m pertechnetate (99mTc) in the diagnosis of the localization of the pathological parathyroid glands in primary hyperparathyroidism and compare the results with those of high resolution ultrasonography. METHODS: Twelve patients of 56.1 +/- 7.8 years of age diagnosed with primary hyperparathyroidism were studied between March 1987 and June 1990. High resolution ultrasonography with a 7.5 MHz transducer and scintigraphy of digital subtraction with 201Tl-99mTc were carried out preoperatively in all the patients. None of the patients had had previous cervical surgery and diagnosis was proven following surgery by histopathologic study. RESULTS: Ultrasonography detected 9 out of 11 adenomas and 3 out of 4 hyperplastic glands. Scintigraphy identified 9 adenomas and only 2 of the hyperplastic glands. With this latter technique there was one false positive. The sensitivity of ultrasonography was 80% and that of scintigraphy was 73% with specificity being 100% vs 96.9%, respectively. CONCLUSIONS: Subtraction 201 Tl-99mTc scintigraphy is useful in the diagnosis of the localization of pathologic parathyroid glands in patients with no previous cervical surgery although in this series this technique did not surpass that of high resolution ultrasonography.

[Renal transplantation in children: punction-aspiration biopsy and renogram with 99mTc-DTPA]. / Trasplante renal en niños: biopsia por punción-aspiración y renograma con 99mTc-DTPA.

BACKGROUND: Renal transplantation in children raises numerous diagnostic problems. The renography obtained with diethyltriaminopentaacetic acid marked with (99mTc metastable technetium (99mTc-DTPA) was compared with fine needle aspiration biopsy (FNAB) in search of a better interpretation of post-transplant crisis: rejection, acute tubular necrosis, toxicity by cyclosporin A and infection. METHODS: Sixteen acute post-transplant episodes were studied in 13 children submitted to renal transplantation. The post-transplant time was 6 days to 2.5 years. The basal renography and FNAB were carried out following the initial clinical manifestations and over a period of less than one week. The vascular and renographic phases were evaluated by interpreting the renography and were compared to previous renographies. The diagnosis of the aspiration biopsy was expressed as: normal, acute tubular necrosis, total necrosis, toxicity by cyclosporin A, viral infection and rejection. RESULTS: Results agreed in 14 out of 16 cases: 1 normal, 3 acute tubular necrosis by renography and cellular necrosis by cytology, 9 rejections and 1 infection (increase in renal transit time). In the 2 cases with total necrosis of 100% followed by loss of renal allograft, the renographic diagnosis was severe vascular rejection with a negative prognosis. CONCLUSIONS: In this series FNAB confirmed the renography as useful in the early diagnosis of complications which may appear in children undergoing renal transplantation.

[Prognostic value of cardiac perfusion scintigraphy associated with the dobutamine test in acute coronary syndromes]. / Valor pronóstico de la gammagrafía cardíaca de perfusión asociada al test de dobutamina en los síndromes coronarios agudos.

OBJECTIVES: This study aimed to establish the value of myocardial ischemia induced by the dobutamine infusion test associated to 99m technetium isonitrile single photon emission computed tomography in patients with unstable angina or non Q-wave infarction during the first days in the Coronary Care Unit. METHODS: Fifty three patients with unstable coronary syndromes and common medical treatment were studied with a moderate-dose dobutamine test (5 to 20 microgram/Kg/min) using a 99mTc-MIBI SPECT. The results were correlated with the incidence of recurrent angina, infarction, death or revascularization. RESULTS: The dobutamine test induced a reversible perfusion defect in 36 patients (68%) and angina in 12 of them (12/36, 33%). However, the patients who had a positive test had a similar incidence of events as those with a negative test (58% vs 59%). Thus, while the sensitivity of the dobutamine test to identify patients at risk was relatively high (68%), its specificity (32%) and its negative predictive value (41%) were low. The patients with dobutamine-induced angina, however, had a higher scintigraphy score (3.0 +/- 1,7 vs 1.6 +/- 1.8, p < 0.02) and a higher incidence of recurrent angina (8/12, 67% vs 13/41, 31%, p < 0.04) than those without, at a comparable double product. CONCLUSIONS: In conventionally treated patients with unstable coronary syndromes, the specificity of the inducible scintigraphic ischemia with moderate dose of dobutamine performed during the first days is too low to be used as a marker for in-hospital events. However, inducible angina with dobutamine suggests an extensive jeopardized area and/or a particularly reduced ischemic threshold.

[Significance of segmentary reversal defects in the myocardial SPECT with 99mTC-tetrofosmin myocardial SPECT]. / Significado de los defectos paradójicos segmentarios en la tomogammagrafía miocárdica con 99mTc-tetrofosmina.

OBJECTIVES: To evaluate segmentary reverse defects (RD) (uptake higher in exercise than in rest) in 99mTc-tetrofosmin SPECT. METHODS AND RESULTS: 1,124 consecutive SPECT studies were reviewed and 80 (7%) segmentary RD were identified. Thirty-eight patients with RD attributed to artifact (extra cardiac uptake) were excluded. Thus, 42 patients (3.6%), 21 with and 21 without previous infarct, were studied. Thirteen out of 21 RD in patients without previous infarct corresponded to inferior region and 8 to the anterior region. In three out of 8 patients in whom the coronary angiography was performed, the coronary arteries were angiographically normal and 5 had stenosis of between 50% to 70% of coronary arteries corresponding to RD. Of the 21 RD in patients with previous infarct, the RD site corresponded to the same region of the necrosis (15 inferior and 6 anterior). All had viability criteria (uptake higher than 40% in more than 50% of the region) in rest uptake SPECT quantification. In nine out of 11 patients in whom a coronary angiography was carried out, patency of the artery responsible for the infarct was verified. CONCLUSIONS: 3.6% of segmentary RD, which were not attributed to the artifact, were observed in myocardial perfusion 99mTc-tetrofosmin SPECT studies. Half of these cases corresponded to regions without previous infarct and with normal coronary arteries or non-severe coronary stenosis. The remaining corresponded to regions with previous infarct and with viability criteria.

[Myocardial perfusion SPECT and isotopic ventriculography in obstructive and non-obstructive hypertrophic myocardiopathy]. / SPET miocárdico de perfusión y ventriculografía isotópica en la miocardiopatía hipertrófica obstructiva y no obstructiva.

OBJECTIVE: To evaluate the role of myocardial perfusion SPET and radionuclide ventriculography in patients with hypertrophic cardiomyopathy (HC). METHODS: Exercise myocardial perfusion SPET with 99mTc-tetrofosmin and radionuclide ventriculography were performed in a consecutive series of 101 patients (54 15 years, 50 women, 55 with dynamic obstruction) diagnosed of HC by echo. Follow-up from the diagnosis was 9,9 6,7 years (1 to 28 years). RESULTS: Thirty six percent of patients had perfusion defects (non reversible in 15 and reversible in 21). In non obstructive HC higher number of patients with non reversible defects (p = 0.01 was obseved and in patients with no reversible defects higher incidence of pathologic Q waves in ECG (p = 0.01), Higher ventricular volumes (p < 0.05), lower ejection fraction (p = 0,0001) and longer time to peak emptying velocity (p < 0.05). There were 4 cardiac deaths, 15 syncopes, 18 pacemakers and 6 myectomy. Ejection fraction was higher in patients with syncope (p = 0,034) and there was no isotopic variable predictive of mortality, pacemaker or myectomy. CONCLUSIONS: Neither SPET nor radionuclide ventriculography have a prognostic role in patients with HC, but patients with syncope have higher values of ejection fraction. Patients with non reversible defects have higher rate of pathologic Q waves in ECG, higher ventricular volumes and lower ejection fraction. This is indicative of evolution to dilated form of HC.

[Tomographic studies of myocardial perfusion normality with 99m Tc-Tetrofosmin. Spanish multicenter study]. / Estudios tomográficos de normalidad de perfusión miocárdica con 99mTc-Tetrofosmina. Estudio multicéntrico español (I). Aspectos técnicos: diseño del estudio y control de calidad.

As a first phase in a nationwide multicenter study to obtain myocardial perfusion normality patterns, this work presents the study design and quality control methodology used to guarantee that the gammacameras fulfilled some minimum quality requirements. The following aspects were considered in the study design in order to guarantee the homogeneity and interchangeability of the results: creation and structure of the work group, data interchange system, data selection and acquisition, centralized archiving and processing, assessment system, study acceptance criteria and distribution of the results. To carry out the instrumental quality control, three phantom studies were established, one to control the rotation center, another to verify tomographic uniformity and a third to simulate the shape and orientation of the left ventricle. The three phantoms circulated through all of the 18 participating centers in this project, which corresponded to 19 gammacameras. Very strict guidelines had to be followed in the acquisition and processing of these phantom studies. If any camera and/or center did not fulfill the criteria established, it was advised of the problem detected in order to correct it. Once the defect was repaired, all the phantoms were sent again for verification. Uniformity of the rotation center was quantified by means of the eccentricity of a 360 degrees orbit, admitting up to a maximum of 10%. Tomographic uniformity was visually assessed, taking in account the number of slices with rings and their contrast and finally no artifacts could be present in the reconstructed study of the ventricle. The center of rotation was within limits in all the cameras except one case while the tomographic uniformity was incorrect in 6 cases. All the departments, except one, corrected the defects detected, and passed the acceptance test. The results made it possible to guarantee adequate homogeneity and instrumental quality in this multicenter study.

[Tomographic studies of myocardial perfusion normality with 99m Tc-Tetrofosmin. Spanish multicenter study]. / Estudios tomográficos de normalidad de perfusión miocárdica con 99mTc-Tetrofosmina. Estudio multicéntrico español (II). Aspectos clínicos.

This objective of this study was to obtain a pool of Myocardial Perfusion SPECTs with a 99mTetrofosmin stress/rest one day protocol in normal volunteers having a less than or equal to 5% likelihood of coronary artery disease that represents normalcy in the Spanish population. A total of 169 volunteers from 15 hospitals were studied. The volunteers were divided into 5 groups: Groups 1, 2 or 3 corresponding to men < 30 years (n = 33), men between 30 and 50 years (n = 32), or men > 50 years (n = 31); Groups 4 or 5: premenopausal (n = 38) or postmenopausal women (n = 35). A clinical history, physical examination, clinical laboratory parameters, echocardiography and a symptom limited exercise stress test were performed in all of them and had to be normal. The mean likelihood of coronary artery disease was 1.15 +/- 1.07%.Twenty-four segments were analyzed in each study and were classified into 5 grades of uptake (1 = normal, 2, 3, 4 = mild, moderate or severe defect and 5 = no uptake). Defects were then analyzed according to sex and location. Considering the stress and rest studies separately (8,112 segments), only 19 moderate and 75 mild defects were found, these corresponding to 16 volunteers, with more inferior defects in men and anterior defects in women. These data validate the normalcy of our population. A pool of Myocardial Perfusion SPECTs with a 99mTetrofosmin stress/rest one day protocol in normal volunteers that represents Spanish normal values was obtained.