RESUMEN
Cardiovascular diseases (CVDs) are the leading cause of death in Latin America and the Caribbean (LAC) region as well as worldwide. Lifestyle, nutritional habits and the upsurge of obesity have contributed to the increase in the prevalence of CVDs in the region. The role of nuclear cardiology in the management of patients with CVDs is well established. Particularly, myocardial perfusion imaging is widely used in LAC countries and has been increasingly integrated into the healthcare systems in the region for the diagnosis of coronary artery disease, risk stratification and to guide patient management. In its role to support countries around the world to address their health needs through the peaceful applications of nuclear techniques, the International Atomic Energy Agency (IAEA) has provided assistance to the LAC region for the establishment and strengthening of the nuclear cardiology practice. To that extent, the IAEA provides support in building capacities of multidisciplinary teams of professionals, the provision of medical equipment and the promotion of communication and exchange of knowledge among the different stakeholders. In addition, the IAEA encourages the participation of nuclear medicine centers in international multi-center research studies. In this paper, we present some of the projects through which the IAEA has supported the LAC region, including regional technical cooperation projects and coordinated research projects related to cardiology within the current multimodality approach to cardiac imaging.
Asunto(s)
Técnicas de Imagen Cardíaca/tendencias , Cardiología/organización & administración , Enfermedades Cardiovasculares/diagnóstico por imagen , Medicina Nuclear/organización & administración , Cintigrafía/tendencias , Región del Caribe , Enfermedad de la Arteria Coronaria/diagnóstico por imagen , Países en Desarrollo , Humanos , Investigación Interdisciplinaria , Agencias Internacionales , Cooperación Internacional , América Latina , Imagen de Perfusión Miocárdica , Medición de RiesgoRESUMEN
Across Latin American and Caribbean countries, cardiovascular disease and especially ischemic heart disease is currently the main cause of death both in men and in women. For most Latin American and Caribbean countries, public and community health efforts aim to define care strategies which are both clinically and cost effective and promote primary and secondary prevention, resulting in improved patient outcomes. The optimal approach to deal with acute events such as ST-elevation myocardial infarction (STEMI) is a matter of controversy; however, there is an expanding role for assessing residual ischemic burden in STEMI patients following primary percutaneous coronary intervention. Although randomized clinical trials have established the value of staged fractional flow reserve-guided revascularization, the use of noninvasive functional imaging modalities may play a similar role at a much lower cost. For LAC, available stress imaging techniques could be applied to define residual ischemia in the non-infarct related artery and to target revascularization in a staged procedure after primary percutaneous coronary intervention The use of nuclear cardiac imaging, supported by its relatively wide availability, moderate cost, and robust quantitative capabilities, may serve to guide effective care and to reduce subsequent cardiac events in patients with coronary artery disease. This noninvasive approach may avert potential safety issues with repeat and lengthy invasive procedures, and serve as a baseline for subsequent follow-up stress testing following the index STEMI event. This consensus document was devised from an expert panel meeting of the International Atomic Energy Agency, highlighting available evidence with a focus on the utility of stress myocardial perfusion imaging in post-STEMI patients. The document could serve as guidance to the prudent and appropriate use of nuclear imaging for targeting therapeutic management and avoiding unnecessary invasive procedures within Latin American and Caribbean countries, where resources could be scarce.
Asunto(s)
Técnicas de Imagen Cardíaca , Pruebas de Función Cardíaca , Infarto del Miocardio con Elevación del ST/diagnóstico por imagen , Región del Caribe/epidemiología , Toma de Decisiones Clínicas , Enfermedad Coronaria/epidemiología , Países en Desarrollo , Electrocardiografía/métodos , Femenino , Humanos , América Latina/epidemiología , Masculino , Estudios Multicéntricos como Asunto , Isquemia Miocárdica/diagnóstico por imagen , Intervención Coronaria Percutánea , Prevalencia , Ensayos Clínicos Controlados Aleatorios como Asunto , Medición de Riesgo , Infarto del Miocardio con Elevación del ST/epidemiología , Infarto del Miocardio con Elevación del ST/terapiaRESUMEN
INTRODUCTION: Radionuclide ventriculography (RNV) evaluates segmental and global ventricular contractility and also detects conduction abnormalities. OBJECTIVE: To assess the temporal parameters of ventricular synchronization in the normal heart by a third harmonic (3H) Fourier phase analysis in a RNV and introduce this technique in our center. MATERIAL AND METHODS: Thirty normal subjects (19 men and 11 women) were included. An equilibrium RNV was performed in 35 degree left anterior oblique projection with 10 degree caudal tilt. The onset (T0); mean time (T(m)); total contraction time (T(t)); final time (T(f)) and propagation time (T(p)) for right (RV) and left ventricle (LV); as well as total propagation time (T(TP)); interventricular time (T(RV-LV)) and septum-lateral wall conduction time (T(S-LW)) were measured on the 3H Fourier histogram of the time-activity curve. RESULTS: Right ventricle contraction started 5 ms before that of the left ventricle (T(0RV) = 66 +/- 38 ms; T(OLV) = 71 +/- 30 ms), with a longer total contraction time (T(tVD) = 67 +/- 28 ms vs T(tVI) = 64 +/- 38 ms). Total propagation time (T(TP)) was 69 +/- 37 ms and the interventricular time (T(RV-LV)) was 2 +/- 25 ms. Contraction progressed from septum to lateral wall, with a septum-lateral wall conduction time (T(S-LW)) of 4 +/- 22 ms. CONCLUSION: Simultaneous contraction of right and left ventricles can be quantified by RNV phase analysis, providing a useful tool for ventricular resynchronization assessment in multisite pacing.
Asunto(s)
Análisis de Fourier , Ventrículos Cardíacos/diagnóstico por imagen , Ventriculografía con Radionúclidos , Función Ventricular/fisiología , Femenino , Humanos , MasculinoRESUMEN
BACKGROUND: Reversal of ischemia after myocardial infarction by revascularization is worthwhile only if viability exists in a sufficiently large portion of the left ventricle. METHODS AND RESULTS: To determine myocardial hypoperfusion reversibility and its influence on segmental and global function, we studied 50 patients after myocardial infarction. Three technetium 99m-tetrofosmin scintigraphies were performed: 1 at rest, 1 after 0.6 mg sublingual nitroglycerin (NTG), and 1 after injection at peak stress. First-pass multigated radionuclide angiography was obtained at rest and after NTG. Each patient also underwent a stress redistribution-reinjection thallium-201 scintigraphy. During stress 99mTc-tetrofosmin, 104 segments had normal uptake, 51 showed moderately reduced uptake, and 186 had severely reduced uptake. Of these 186 segments, 33 (18%) improved at rest, and 41 (22%) improved only after NTG. Fifty-nine (79%) of these segments with improved uptake were also found to have reversible defects on 201TI imaging. In the 26 patients with ventricular dysfunction, a 73% agreement was found between the functional and 99mTc-tetrofosmin uptake post-NTG improvement, whereas a 69% agreement was found with thallium reinjection. No significant differences were seen between 99mTc-tetrofosmin and 201T1 imaging. CONCLUSION: Nitroglycerin administration during 99mTc-tetrofosmin scintigraphy improves the detection of myocardium with reversible hypoperfusion in patients with a previous myocardial infarction.
Asunto(s)
Circulación Coronaria , Corazón/diagnóstico por imagen , Nitroglicerina/farmacología , Compuestos Organofosforados , Compuestos de Organotecnecio , Vasodilatadores/farmacología , Adulto , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Infarto del Miocardio/diagnóstico por imagen , Angiografía por Radionúclidos , Radioisótopos de TalioRESUMEN
Dynamic cardiomyoplasty improves ventricular function by increasing pump function and by limiting cardiac dilatation. The aim of this study was to assess long-term myocardial performance by radionuclide ventriculography on dilated cardiomyopathy patients subjected to cardiomyoplasty. Thirteen survivors were included. Radionuclide ventriculography was performed one week before surgery and one year later. Five patients were also studied two years following surgery. The left ventricular ejection fraction (LVEF), end-diastolic volume (EDV) and ventricular amplitude ratio (VAR) to assess mitral regurgitation were measured. Every case after one year showed a non-significant increase in LVEF. However, the decrease in EDV and in VAR was significant (p < 0.01). No significant difference in these values was found after two years. We conclude that the effects of cardiomyoplasty--reduction of cardiac dilatation, wall stress and mitral regurgitation--are more evident during the first year after surgery. Thereafter, a certain stabilization is observed.
Asunto(s)
Cardiomioplastia , Ventriculografía con Radionúclidos , Adulto , Cardiomiopatía Dilatada/diagnóstico por imagen , Cardiomiopatía Dilatada/fisiopatología , Cardiomiopatía Dilatada/cirugía , Femenino , Humanos , Masculino , Persona de Mediana Edad , Volumen Sistólico , Función Ventricular IzquierdaRESUMEN
Of 33 children with membranous nephropathy screened for HBs Ag, 14 were found to be HBs Ag carriers, whereas HBs Ag was detected in 3 of 170 and 4 of 100 children with glomerular and nonglomerular kidney diseases, respectively. HBs Ag was often associated with acute hepatitis at onset (five patients) or with elevated transminases values. This high incidence and the prevalence of an unusual subtype (ayw2) suggest a relationship between HBs Ag and the glomerular lesions. Using immunofluorescence, however, HBs Ag could not be detected within the deposits, so that the nature of the relationship cannot be considered as established. The clinical outcome (50% remission), the plasma complement component disturbances, and findings by immunofluorescence did not differ from those observed in children with MGN without detectable HBs Ag.