Sobre algunos términos de uso frecuente en Medicina Nuclear / On some terms of frequent use in nuclear Medicine

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[Diagnostic value of gated-SPECT for each coronary artery in patients clinically diagnosed of coronary heart disease]. / Valor diagnóstico del gated-SPECT para cada arteria coronaria en pacientes con el diagnóstico clínico de cardiopatía isquémica.

UNLABELLED: This study aimed to evaluate the diagnostic value of gated-SPECT for each coronary artery in patients with clinical diagnosis or suspicion of coronary heart disease. PATIENTS AND METHODS: The study population is made up of 43 patients (64 9 years, 88% male gender) with prior clinical diagnosis or suspicion of coronary heart disease who had undergone gated-SPECT (99mTc-tetrofosmin) and cardiac catheterization. Scintigraphic study after exercise treadmill test and rest study were performed on the same day. RESULTS: Gated-SPECT showed perfusion defects in 86% of patients, the mean number of territories with perfusion defects being 1.58 +/- 0.79. A total of 39 (91%) of the 43 patients had significant coronary heart disease. Single, two- and three-vessel disease was demonstrated in 12 (28%), 15 (35%) and 12 (28%) patients, respectively. Sensitivity and specificity were 81% and 91%, respectively, for left anterior descending artery, 88% and 65% for right coronary artery, and 55% and 81% for circumflex one. CONCLUSIONS: Myocardial scintigraphy with gated-SPECT offers high sensitivity and specificity for the diagnosis of left anterior descending artery disease. However, sensitivity for circumflex artery and specificity for right coronary artery were low in our series.

[Clinical predictors of the presence of perfusion defects in more than than one territory in myocardial scintigraphy with GATED-SPECT]. / Predictores clínicos de la existencia de defectos de perfusión de más de un territorio en la gammagrafía de perfusión miocárdica con GATED-SPECT.

BACKGROUND AND OBJECTIVE: Extension of perfusion defects is associated with outcome in patients undergoing myocardial scintigraphy. The study aimed to identify the clinical characteristics that can predict the existence of perfusion defects in more than one territory in patients referred for myocardial scintigraphy with GATED-SPECT. PATIENTS AND METHODS: A total of 193 patients undergoing myocardial scintigraphy with GATED-SPECT (99mTc-tetrofosmine) were studied. Clinical variables and scintigraphy results were studied to determine what clinical variables are associated with perfusion defects in more than one territory. RESULTS: The number of territories with perfusion defects per patient was 1.1 0.8 and 29% had perfusion defects in > 1 territory. Patients with greater probability of having perfusion defects in > 1 territory were those with previous myocardial infarction (44% vs 21%, p = 0.030) and males (33% vs 10%, p = 0.006). In addition, patients with > 2 coronary risk factors had a statistical tendency to have defects in > 1 territory (47% vs 20%, p = 0.057). Only 15% of the patients with one of these three characteristics had perfusion defects in > 1 territory in comparison with 45% and 83% in those with 2 or 3 factors, respectively. CONCLUSION: Considering 3 simple clinical characteristics (male gender, previous infarction and existence of > 2 coronary risk factors), it is possible to predict which patients are more likely to show perfusion defects in > 1 territory during GATED-SPECT myocardial scintigraphy.

Predictores clínicos de la existencia de defectos de perfusión de más de un territorio en la gammagrafía de perfusión miocárdica con GATED-SPECT / Clinical predictors of the presence of perfusion defects in more than one territory in myocardial scintigraphy with gated spect

Introducción y objetivo: La extensión de los defectos de perfusión es un marcador pronóstico en los pacientes a los que se realiza gammagrafía de perfusión miocárdica. El objetivo fue determinar qué variables clínicas pueden predecir la existencia de defectos de perfusión en más de un territorio en pacientes a los que se realiza gammagrafía de perfusión miocárdica mediante GATED-SPECT. Pacientes y métodos: Se estudiaron 193 pacientes a los que se realizó estudio de perfusión miocárdica mediante GATEDSPECT con 99mTc-tetrofosmina. Se analizaron las variables clínicas y el resultado del estudio isotópico, con objeto de determinar las características asociadas a la existencia de defectos de perfusión en > 1 territorio. Resultados: El número de territorios con defectos de perfusión por paciente fue 1,1 ñ 0,8 y el 29 per cent presentaron defectos de perfusión en > 1 territorio. Los pacientes con mayor probabilidad de tener defectos de perfusión en > 1 territorio fueron aquellos con infarto de miocardio previo (44 per cent vs 21 per cent, p = 0,030) y los varones (33 per cent vs 10 per cent, p = 0,006). Además, los pacientes con > 2 factores de riesgo coronario presentaron una tendencia estadística a tener más frecuentemente defectos de perfusión en > 1 territorio (47 per cent vs 20 per cent, p = 0,057).Sólo el 15 per cent de los pacientes con una de estas tres características tuvieron defectos de perfusión en > 1 territorio, en comparación con el 45 per cent y el 83 per cent de los que presentaron dos o tres factores, respectivamente. Conclusiones: Teniendo en cuenta tres variables clínicas sencillas (sexo masculino, infarto previo y existencia de > 2 factores de riesgo), podemos conocer qué pacientes tienen mayor probabilidad de presentar defectos de perfusión en más de un territorio en el estudio mediante GATED-SPECT (AU)

Valor diagnóstico del GATED-SPECT para cada arteria coronaria en pacientes con el diagnóstico clínico de cardiopatía isquémica / Diagnostic value of gated-spect for each coronary artery in patients clinically diagnosed of coronary heart disease

El objetivo de este estudio fue evaluar el valor diagnóstico del gated-SPECT para cada una de las arterias coronarias en pacientes con diagnóstico previo o sospecha de enfermedad coronaria. Pacientes y métodos: La población de estudio esta formada por 43 pacientes (64 ñ 9 años, 88 per cent varones) con diagnóstico previo o sospecha de cardiopatía isquémica a los que se les había realizado estudio gated-SPECT y coronariografía. El radiofármaco empleado fue 99mTc-tetrofosmina, realizándose en el mismo día el estudio tras ejercicio físico en tapiz rodante y el estudio de reposo. Resultados: El estudio gated-SPECT mostró defectos de perfusión en el 86 per cent de los pacientes, siendo el número de territorios con defecto de perfusión por paciente 1,58 ñ 0,79.De los 43 pacientes, 39 (91 per cent) tenían enfermedad coronaria significativa. La enfermedad fue de 1, 2 y 3 vasos en 12 (28 per cent), 15 (35 per cent) y 12 (28 per cent) pacientes, respectivamente. La sensibilidad y especificidad fueron, respectivamente, 81 per cent y 91 per cent para la descendente anterior, 88 per cent y 65 per cent para la coronaria derecha y 55 per cent y 81 per cent para la circunfleja. Conclusiones: En pacientes con diagnóstico previo o sospecha de cardiopatía isquémica, la gammagrafía mediante gated-SPECT posee una elevada sensibilidad y especificidad en el diagnóstico de enfermedad de la arteria descendente anterior. Sin embargo, la sensibilidad para la circunfleja y la especificidad para la coronaria derecha fueron bajas en nuestra serie. (AU)

Mechanism of syncope in patients with bundle branch block and negative electrophysiological test.

BACKGROUND: In patients with syncope and bundle branch block (BBB), syncope is suspected to be attributable to a paroxysmal atrioventricular (AV) block, but little is known of its mechanism when electrophysiological study is negative. METHODS AND RESULTS: We applied an implantable loop recorder in 52 patients with BBB and negative conventional workup. During a follow-up of 3 to 15 months, syncope recurred in 22 patients (42%), the event being documented in 19 patients after a median of 48 days. The most frequent finding, recorded in 17 patients, was one or more prolonged asystolic pause mainly attributable to AV block; the remaining 2 patients had normal sinus rhythm or sinus tachycardia. The onset of the bradycardic episodes was always sudden but was sometimes preceded by ventricular premature beats. The median duration of the arrhythmic event was 47 seconds. An additional 3 patients developed nonsyncopal persistent III-degree AV block, and 2 patients had presyncope attributable to AV block with asystole. No patients suffered injury attributable to syncopal relapse. CONCLUSIONS: In patients with BBB and negative electrophysiological study, most syncopal recurrences have a homogeneous mechanism that is characterized by prolonged asystolic pauses, mainly attributable to sudden-onset paroxysmal AV block.

Autocapture compatibility in patients with the MembraneEX lead and Affinity pulse generators.

The first Autocapture generation worked well with all recommended leads. The newer Autocapture generation provides a more sensitive resolution for evoked response testing and its implementation in a dual-chamber device. The purpose of the study was to evaluate the performance of the Affinity SR/DR pacemaker with the new Autocapture algorithm in combination with the small surface area pacing lead MembraneEX in 129 patients. Autocapture ventricular threshold, sensing threshold, lead impedance, evoked response (ER) and polarization signals were determined at implantation and discharge, as well as after 1 and 3 months. Autocapture recommendation rate was based on the ER sensitivity test. The median pacing threshold was 0.38, 0.50, 0.75, 0.75 V at implant, discharge, 1 and 3 months post-implant, respectively. The respective data for median lead impedance were 744, 605, 649 and 691 ohms; median sensing threshold was 12.5 mV at all visits. The median ER amplitude was 9.0, 10.1, 9.9 and 10.1 mV and the median polarization signal 0.39 mV at all visits. The frequency of recommended Autocapture activation was 98.3%, 99.2%, 98.3% and 96.2% of all patients at implant, at discharge, 1 and 3 months post-implant respectively. In conclusion, the studied pulse generator enabled, in combination with this pacing lead, in >95% of all patients activation of Autocapture.

[Study of active myocardial damage in children with suspected myocarditis using antimyosin monoclonal antibodies (AMMoAb-111In)]. / Estudio evolutivo del daño miocárdica activo en niños con sospecha de miocarditis mediante anticuerpos monoclonales antimiosina (AbMoAM-111In).

BACKGROUND: The study with monoclonal antimyosin antibody-111In has proved to be useful in the detection of the myocardial damage present in different processes. There is active myocardial damage and specific antimyosin uptake in myocarditis, as both experimental and clinical trials have shown. In experimental models the evolution of myocardial damage has been studied, where a parallelism between the histological changes of the myocardial damage and the evolution on the antimyosin uptake has been found. In clinical myocarditis it is difficult to do an histological follow up of the inflammatory process, and therefore the evolution of myocardial damage present in myocarditis is unknown. The antimyosin antibody images allow a non-invasive study of this evolution. OBJECTIVES: a) to study with monoclonal antimyosin antibody-111In, the myocardial damage present regarding the disease evolution in children with suspected clinical diagnosis of myocarditis; b) to evaluate the evolution of the active myocardial damage reflected on the changes on the monoclonal antimyosin antibody-111In uptake. METHODS: A study with monoclonal antimyosin antibody-111In was carried out on 43 children, 16 males and 27 females with a median age of 39 months (SD 48 m; range: 2-167) with suspected diagnosis of acute myocarditis defined as the presence of congestive cardiac failure or severe ventricular arrhythmia with less than 12 months of evolution. The image evaluation was done visually and through the heart to lung ratio. Twenty of these patients were also followed up with antimyosin antibody scan for a period of 19 +/- 9 months, and 3.8 +/- 1.7 studies were performed on them in this time. RESULTS: The prevalence of positive myocardial uptake was 83.72%. There is a negative correlation (r = -0.352; p < 0.02) between the evolution time of the process and the heart to lung ratio: patients studied before two months, have a higher heart to lung ratio and greater prevalence of positive studies than those studied later (heart to lung ratio 2.09 vs 1.74; p = 0.013; 90% vs 69.2%). Of the patients followed up with antimyosin antibody scans, 6 showed a clinical relapse which increased their heart to lung ratio. The other 14 showed an progressive decrease of the heart to lung ratio reaching normality in 14 +/- 6 months. CONCLUSIONS: a) the uptake intensity of monoclonal antimyosin antibody-111In, as a reflection of the myocardial damage, depends on the disease evolution time, as in the first two months is when the major damage happens; b) the uptake intensity slowly decreases, tending to normality around the 14th month, although this evolution may be altered by the appearance of relapses.