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Albert Flotats

Publications and source records attributed to Albert Flotats.

15 recordsLinked to original sources
PubMed2006

The sequence of regional ventricular motion.

OBJECTIVE: The chronology of electrical events that mechanically activate the myocardium has been described as initiating at the level of the septum, spreading to the apex, then to the bodies of both ventricles and eventually to the base of the heart (apex-to base activation). It has recently been suggested that the myocardium is a single muscular band that conforms a double-loop helicoid. Contraction of the myocardium would follow the trajectory of the muscular fibers that originate at the pulmonary artery towards the body of the left ventricle and to the aorta (base-to apex contraction). This would explain the movements of the base of the heart and the twisting motion of the ventricles seen at magnetic resonance studies. METHODS: Temporal Fourier analysis of equilibrium radionucleide angiocardiography, by studying the topography of the regional myocardial mechanical displacement corresponding to the wave front of electro-mechanical activation, provides information on the sequence of regional ventricular contraction was used in 29 normal individuals to observe the sequence of myocardial motion. RESULTS: Analysis disclosed that the base of the heart first moves (right then left ventricle) and mechanical movement later descends to involve the apex and the septum. These findings are in concordance with the proposed activation of the helical myocardium and open the way to more complex studies. CONCLUSIONS: Although electrical activation of the myocardium (QRS complex) follows a septum-apex-body-base of the left ventricle sequence, mechanical activation follows a base-to-apex sequence. This is likely to be related to anisotropic propagation of the electromechanical stimulus throughout the myocardial band once the electrical stimulus has been delivered at the base of the heart.

Electrocardiography↗
PubMed2006

Value of radionuclide studies in cardiac transplantation.

Effective noninvasive evaluation of acute and chronic allograft rejection remains an important challenge in patients with cardiac transplantation. Radionuclide studies have demonstrated utility because of their ease of use, giving relevant information about the pathophysiology of the transplanted heart, along with valuable diagnostic and prognostic indicators. This article focuses on reviewing the pathophysiological changes of the transplanted heart and implications for radionuclide studies.

Graft Rejection↗
PubMed2004

Left ventricular end-diastolic volume is decreased at maximal exercise in athletes with marked repolarisation abnormalities: a continuous radionuclide monitoring study.

PURPOSE: Although marked repolarisation abnormalities (MRAs) are considered innocuous in trained athletes, their functional significance awaits clarification. The aim of this study was to further evaluate the pathophysiological implications of such MRAs. METHODS: We compared left ventricular (LV) functional response to exhausting exercise in 39 male athletes with (n=22) or without (n=17) MRAs and with no structural cardiac abnormalities, by means of a portable radionuclide monitoring system (Vest, Capintec, Inc., Ramsey, NJ). MRAs were defined by the presence of negative T waves > or =2 mm in three or more rest ECG leads. The Vest data were averaged for 30 s and analysed at baseline and at different heart rate (HR) values (50%, 75%, 85%, 95% and 100% of peak HR), as well as at 2, 5 and 10 min of recovery. RESULTS: There were no significant differences in the effect of exhausting exercise between athletes with and athletes without MRAs. However, there was a significant difference in the trend in end-diastolic volume (EDV) during exercise depending upon the group of athletes considered (p=0.05). EDV differed significantly between the two groups of athletes at peak HR (p=0.031). EDV in athletes with MRAs was lower than that in athletes without MRAs (102%+/-7% vs 107%+/-8%, p=0.034). CONCLUSION: EDV is decreased at peak HR in athletes with MRAs. Such high HR values are infrequently achieved or maintained during sporting activities; therefore, in the absence of structural heart disease, MRAs should not preclude physical training and competitive availability.

Adult↗
PubMed2004

Challenging the neuronal MIBG uptake by pharmacological intervention: effect of a single dose of oral amitriptyline on regional cardiac MIBG uptake.

PURPOSE: Imaging with metaiodobenzylguanidine (MIBG) is used for the assessment of neuronal dysfunction in various cardiovascular disorders. Although valuable information is obtained by resting MIBG imaging, it is conceivable that competitive interference with the re-uptake mechanism would exaggerate MIBG defects and might unmask subclinical neuronal dysfunction. Tricyclic antidepressants, such as amitriptyline, have been reported to significantly increase cardiac MIBG washout and inhibit uptake into presynaptic neurons. This study was undertaken to assess whether a single oral dose of amitriptyline could influence cardiac MIBG distribution. METHODS: Six patients (aged 62-81 years; four males, two females) who had demonstrated a normal cardiac MIBG scan during work-up for movement disorders were studied. The patients underwent a second 123I-MIBG study after oral administration of 25 mg amitriptyline within 1 week. Single-photon emission computed tomography images were acquired at 4 h to assess the regional distribution of MIBG, after generation of polar maps and employing a 20-segment model. Mean percentage of peak activity was calculated for each segment at rest and after amitriptyline administration. RESULTS: After amitriptyline administration, there was a decrease in regional MIBG uptake in 10+/-4 segments per patient [62/120 segments (52%): 37 segments with a 5-10% decrease, 25 segments with a >10% decrease]. This change was statistically significant in lateral (P=0.003), apical (P<0.0001) and inferior (P=0.03) regions. CONCLUSION: A single oral dose of amitriptyline can induce changes in the uptake and retention of cardiac MIBG, indicating the feasibility of use of pharmacological intervention in cardiac neurotransmission imaging.

3-Iodobenzylguanidine↗
PubMed2004

99mTc-depreotide scintigraphy of bone lesions in patients with lung cancer.

PURPOSE: Scintigraphy with 99mTc-depreotide, a somatostatin analogue-technetium ligand, has been used for evaluation of various malignant neoplasms, including lung cancer. The diagnosis of bone metastases in patients with lung cancer is not always definitive with current imaging methods. Visualisation of somatostatin receptors (SSTRs) in bone lesions, when the primary tumour exhibits such receptors, could be helpful in characterising them as metastatic. The aim of this study was to assess the value of 99mTc-depreotide in differentiating between benign and malignant bone lesions in patients with lung cancer. METHODS: The study population comprised 20 patients (17 males and three females, mean age 63 years) with proven lung cancer in whom bone lesions had been detected by conventional imaging methods. All patients underwent 99mTc-hydroxydiethylene diphosphonate and 99mTc-depreotide scintigraphy within 2 weeks. Bone lesions were classified as benign or malignant on the basis of clinical, imaging and/or histological criteria. RESULTS: 99mTc-depreotide uptake in the primary tumour was seen in 19 of the 20 patients. Conventional imaging methods detected 55 bone lesions, 31 of which were classified as malignant. Twenty-eight (90%) of these lesions showed 99mTc-depreotide uptake, suggesting bone metastases, while three did not. Twenty-four bone lesions were classified as benign by conventional imaging methods, and none of them showed 99mTc-depreotide uptake. In addition, 99mTc-depreotide demonstrated extra-osseous lesions in six patients. CONCLUSION: In patients with lung cancer and bone lesions, 99mTc-depreotide scintigraphy uptake in the bone lesions supports the diagnosis of malignancy, in particular if the primary lung tumour also exhibits SSTRs. Furthermore, whole-body 99mTc-depreotide scintigraphy may disclose extra-osseous disease.

Adult↗
PubMed2004

Individual renal function based on 99mTc dimercaptosuccinic acid uptake corrected for renal size.

BACKGROUND: Decreased relative 99mTc dimercaptosuccinic acid (99mTc-DMSA) uptake can be a consequence of abnormal kidney size, associated with normal or impaired function. When there is a small kidney, relative 99mTc-DMSA uptake is decreased, and it is sometimes difficult to distinguish a small, normal kidney from a hypofunctioning kidney. Here, relative renal function was studied by quantifying the relative 99mTc-DMSA uptake corrected for renal size (RCU). METHODS: Five hundred and fifty-five consecutive patients (184 adults) aged 1 month to 82 years (mean, 14.8 years) underwent a 99mTc-DMSA study for various renal diseases. Results were compared with the relative 99mTc-DMSA uptake without size correction (RUU). Visual evaluation of images was also performed. RESULTS: In 288 patients (52%) the relative 99mTc-DMSA uptake was normal, either uncorrected or corrected, for renal size; in 184 (33%) it was abnormal by both quantification methods; and in 83 (15%) it was abnormal only by one method. Two hundred and fifty-seven patients (46%) presented with decreased RUU in one kidney, associated with a small kidney in 73 patients (13%). RCU was normal in all of these 73 patients (100%, P<0.0001). The sensitivity and specificity of RCU for evaluating renal function in relation to small renal size and with respect to RUU were 72% and 97%, with positive and negative predictive values of 95% and 80%, and an accuracy of 85%. Visual analysis of the 73 studies with decreased RUU and normal RCU showed a small, normal kidney on 55 occasions (75%), cortical scars in eight (11%), and impaired bilateral function in 10 (14%). Visual analysis of 10 studies with normal RUU and decreased RCU showed dilated pyelocalyceal system in seven occasions (70%) and normal kidneys in three (P<0.0001). CONCLUSION: It is concluded that relative 99mTc-DMSA uptake corrected for renal size is a more accurate method for assessing individual renal function. When there is a small kidney, relative 99mTc-DMSA uptake corrected for renal size can distinguish between a normal and a hypofunctioning kidney.

Adolescent↗
PubMed2003

Non-invasive in vivo imaging of myocardial apoptosis and necrosis.

Myocardial necrosis plays an important role in the pathogenesis of various cardiovascular disorders and can result from different myocardial insults. Its non-invasive identification and localisation therefore may help in the diagnosis of these disorders, as well as in prognosis and assessment of treatment response. Apoptosis, or programmed cell death, is important in the spectrum of myocardial damage since it is gradually becoming more apparent that cell death may begin as apoptosis and not as necrosis. First attempts to directly visualise the area of myocardial necrosis were based on recognition of myocardial infarction with "hot spot imaging agents" in patients with chest pain. Since then, the study of myocardial necrosis with gamma imaging agents has gone beyond the detection of myocardial infarction, and attempts have been made to diagnose other cardiovascular disorders associated with cardiac cell death such as heart transplant rejection, myocarditis, cardiotoxicity and cardiomyopathies. Traditionally, two hot spot imaging agents have been used for the detection of myocardial necrosis, (99m)Tc-pyrophosphate and (111)In-antimyosin. In addition, preliminary studies have demonstrated promising results with (99m)Tc-glucarate. Recently, (99m)Tc-annexin V has been successfully used for non-invasive gamma imaging of apoptosis after acute myocardial infarction, acute myocardial ischaemia, acute cardiac allograft rejection and malignant intracardiac tumours. This review article focusses on the characteristics of these different myocardial necrotic and apoptotic markers and compares their role in the assessment of myocardial damage.

Annexin A5↗
PubMedDate not supplied

Cardiac neurotransmission SPECT imaging.

The sympathetic nervous system has great influence on cardiovascular physiology. Cardiac neurotransmission single photon emission computed tomography (SPECT) imaging allows in vivo noninvasive assessment of presynaptic reuptake and storage of neurotransmitters, which offers characterization of the cardiac neuronal function in different diseases of the heart and other altered metabolic or functional conditions. Therefore assessment of the integrity of cardiac sympathetic innervation may help in the diagnosis of these disorders, as well as in prognostication, and will result in better therapy and outcome. At present, the most widely available SPECT tracer by which to assess cardiac neurotransmission is metaiodobenzylguanidine labeled with iodine 123. This article focuses on reviewing the characteristics of cardiac SPECT imaging with I-123 metaiodobenzylguanidine and its role in the assessment of pathophysiologic changes during relevant clinical conditions.

3-Iodobenzylguanidine↗