Derangement of PaCO2 requires physician attention in acute carbon monoxide poisoning.

The objective was to describe the prevalence of derangement of the partial pressure of arterial carbon dioxide (PaCO2) and to determine the association between PaCO2 and adverse cardiovascular events (ACVEs) in carbon monoxide (CO)-poisoned patients. Additionally, we evaluated whether the derangement of PaCO2 was simply secondary to metabolic changes. This retrospective study included 194 self-breathing patients after CO poisoning with an indication for hyperbaric oxygen therapy and available arterial blood gas analysis at presentation and 6 h later. The incidence rate of hypocapnia at presentation after acute CO poisoning was 67.5%, and the mean PaCO2 during the first 6 h was 33 (31-36.7) mmHg. The most common acid-base imbalance in 131 patients with hypocapnia was primary respiratory alkalosis. The incidence rate of ACVEs during hospitalization was 50.5%. A significant linear trend in the incidence of ACVEs was observed across the total range of PaCO2 variables. In multivariate regression analysis, mean PaCO2 was independently associated with ACVEs (odds ratio 0.051; 95% confidence interval 0.004-0.632). PaCO2 derangements were common after acute CO poisoning and were not explainable as a mere secondary response to metabolic changes. The mean PaCO2 during the first 6 h was associated with ACVEs. Given the high incidence of ACVEs and PaCO2 derangement and the observed association between the mean PaCO2 and ACVEs, this study suggests that (1) PaCO2 should be monitored in the acute stage to predict and/or prevent ACVEs and (2) further investigation is needed to validate this result and explore the early manipulation of PaCO2 as a treatment strategy.

Biventricular dyssynchrony on cardiac magnetic resonance imaging and its correlation with myocardial deformation, ventricular function and objective exercise capacity in patients with repaired tetralogy of Fallot.

BACKGROUND: Electrical dyssynchrony and prolonged QRS duration are common in patients with repaired tetralogy of Fallot (ToF). It has been linked to increased risk of sudden cardiac death and right ventricular (RV) dysfunction. We investigated myocardial dyssynchrony using cardiac magnetic resonance imaging (CMR) and feature tracking analysis (FT) in this setting and compared it to myocardial deformation, conventional parameters of ventricular dysfunction and clinical parameters. METHODS AND RESULTS: Patients underwent standardized CMR investigations as part of a nationwide study. We prospectively assessed myocardial deformation and analysed regional wall motion abnormalities of the RV and the left ventricle (LV) using CMR-FT. The main measure of dyssynchrony was the maximal time difference (wall motion delay) of the regional strain as a parameter of mechanical biventricular dyssynchrony. In addition, clinical parameters and measures of cardiopulmonary exercise capacity were available. Overall 345 patients were included. Parameters of biventricular wall motion delay correlated significantly with global FT-strain parameters (p < 0.0001 for all imaging planes assessed). Furthermore, we found a significant correlation between circumferential RV motion delay and QRS duration (p = 0.006). Higher LV and RV wall motion delay parameters were also associated with lower peak oxygen consumption (p < 0.05) and a worse LV and RV ejection fraction (p < 0.02). CONCLUSIONS: Assessment of mechanical dyssynchrony is feasible using CMR-FT in ToF patients. Parameters of mechanical dyssynchrony correlate with electrical dyssynchrony, biventricular function and objective exercise capacity in this setting. Due to the weak degree of correlation, however, the clinical significance of these findings remains to be clarified by further studies.

Polyphenol-Rich Fraction of Parquetina nigrescens Mitigates Dichlorvos-Induced Cardiorenal Dysfunction Through Reduction in Cardiac Nitrotyrosine and Renal p38 Expressions in Wistar Rats.

Parquetina nigrescens is commonly used to treat diseases in humans and animals in developing countries, including Nigeria. This study evaluates the effects of its polyphenol-rich fraction (prf) on dichlorvos-induced cardio- and renal toxicity. There were several factors assessed during this study, including cardiac and renal markers, serum myeloperoxidase and xanthine oxidase, and electrocardiograph (ECG) changes. The changes in electrocardiograph (ECG) were recorded. Immunohistochemistry of cardiac and renal p38 and nitrotyrosine was determined. Dichlorvos exposure caused a significant decrease in L-glutathione (reduced glutathione) and other antioxidant enzymes with increases in malondialdehyde, myeloperoxidase, advanced oxidation protein products, and protein carbonyl levels. It also brought about alterations in microanatomy of the heart and kidneys accompanied by increases in serum creatinine and urea levels. Exposure to dichlorvos induced prolonged QRS interval and shortened QT durations in rats. Immunohistochemistry revealed lower expressions of cardiac nitrotyrosine and renal p38 (mitogen-activated protein kinase; MAPK) in rats treated with prf of P. nigrescens. Combining all, prf of P. nigrescens demonstrated antioxidant as well as protective properties in the heart and kidneys of rats exposed to dichlorvos. It ameliorated dichlorvos-induced cardio- and nephrotoxicity giving credence to its use in ethnomedicine.

Fatty Acid Oxidation and Its Relation with Insulin Resistance and Associated Disorders.

Alterations in muscle fatty acid metabolism have been implicated in mediating the severity of insulin resistance. In the insulin resistant heart fatty acids are favored as an energy source over glucose, which is thus associated with increased fatty acid oxidation, and an overall decrease in glycolysis and glucose oxidation. In addition, excessive uptake and beta-oxidation of fatty acids in obesity and diabetes can compromise cardiac function. In animal studies, mice fed a high fat diet (HFD) show cardiac insulin resistance in which the accumulation of intra-myocardial diacylglycerol has been implicated, likely involving parallel signaling pathways. A HFD also results in accumulation of fatty acid oxidation byproducts in muscle, further contributing to insulin resistance. Carnitine acetyltransferase (CrAT) has an essential role in the cardiomyocyte because of its need for large amounts of carnitine. In the cardiomyocyte, carnitine switches energy substrate preference in the heart from fatty acid oxidation to glucose oxidation. This carnitine-induced switch in fatty acid oxidation to glucose oxidation is due to the presence of cytosolic CrAT and reverse CrAT activity. Accordingly, inhibition of fatty acid oxidation, or stimulation of CrAT, may be a novel approach to treatment of insulin resistance.

Alternative right ventricular pacing sites.

BACKGROUND: The main adverse effect of chronic stimulation is stimulation-induced heart failure in case of ventricular contraction dyssynchrony. Because of this fact, new techniques of stimulation should be considered to optimize electrotherapy. One of these methods is pacing from alternative right ventricular sites. OBJECTIVES: The purpose of this article is to review currently accumulated data about alternative sites of cardiac pacing. MATERIAL AND METHODS: Medline and PubMed bases were used to search English and Polish reports published recently. RESULTS: Recent studies report a deleterious effect of long term apical pacing. It is suggested that permanent apical stimulation, by omitting physiological conduction pattern with His-Purkinie network, may lead to electrical and mechanical dyssynchrony of heart muscle contraction. In the long term this pathological situation can lead to severe heart failure and death. Because of this, scientists began to search for some alternative sites of cardiac pacing to reduce the deleterious effect of stimulation. Based on current accumulated data, it is suggested that the right ventricular outflow tract, right ventricular septum, direct His-bundle or biventricular pacing are better alternatives due to more physiological electrical impulse propagation within the heart and the reduction of the dyssynchrony effect. These methods should preserve a better left ventricular function and prevent the development of heart failure in permanent paced patients. As there is still not enough, long-term, randomized, prospective, cross-over and multicenter studies, further research is required to validate the benefits of using this kind of therapy. CONCLUSIONS: The article should pay attention to new sites of cardiac stimulation as a better and safer method of treatment.

Hypothalamic PGC-1α protects against high-fat diet exposure by regulating ERα.

High-fat diets (HFDs) lead to obesity and inflammation in the central nervous system (CNS). Estrogens and estrogen receptor α (ERα) protect premenopausal females from the metabolic complications of inflammation and obesity-related disease. Here, we demonstrate that hypothalamic PGC-1α regulates ERα and inflammation in vivo. HFD significantly increased palmitic acid (PA) and sphingolipids in the CNS of male mice when compared to female mice. PA, in vitro, and HFD, in vivo, reduced PGC-1α and ERα in hypothalamic neurons and astrocytes of male mice and promoted inflammation. PGC-1α depletion with ERα overexpression significantly inhibited PA-induced inflammation, confirming that ERα is a critical determinant of the anti-inflammatory response. Physiologic relevance of ERα-regulated inflammation was demonstrated by reduced myocardial function in male, but not female, mice following chronic HFD exposure. Our findings show that HFD/PA reduces PGC-1α and ERα, promoting inflammation and decrements in myocardial function in a sex-specific way.

Volatile substance misuse: an updated review of toxicity and treatment.

Educational campaigns and legislative actions may have led to an overall decrease in the prevalence of volatile substance misuse (VSM) in many countries; however, it is still a common practice throughout the world. Studies currently suggest that girls are misusing volatile substances more than before and at a prevalence rate equal to or exceeding that of boys in several countries. Products that may be misused are ubiquitous and relatively easy to acquire. The most commonly misused substances in recent studies are fuels such as butane or petrol and compressed gas dusters and deodorants that may contain fluorocarbons and/or butane. Detection of VSM is challenging, therefore physicians must maintain a high level of suspicion based on history and clinical presentation. Clues to misuse are often subtle and may include the patient's proximity to a volatile substance or paraphernalia when found intoxicated, dermal burns, blisters, pigments, or rashes, and chemical odors. The primary targets of toxicity are the brain and the heart. The leading cause of death from VSM is from ventricular dysrhythmias. Treatment of toxicity begins with support of airway, breathing, and circulation. Exogenous catecholamines should be avoided if possible due to the theoretical "sensitized" and irritable myocardium. In the case of ventricular dysrhythmias, direct current defibrillation and/or beta-adrenergic receptor antagonism should be used. New evidence demonstrates the addictive potential of VSM yet effective therapy remains uncertain. Further research is needed in developing methods for preventing, detecting, and treating the harmful effects of VSM.

Dehydroepiandrosterone restores right ventricular structure and function in rats with severe pulmonary arterial hypertension.

Current therapy of pulmonary arterial hypertension (PAH) is inadequate. Dehydroepiandrosterone (DHEA) effectively treats experimental pulmonary hypertension in chronically hypoxic and monocrotaline-injected rats. Contrary to these animal models, SU5416/hypoxia/normoxia-exposed rats develop a more severe form of occlusive pulmonary arteriopathy and right ventricular (RV) dysfunction that is indistinguishable from the human disorder. Thus, we tested the effects of DHEA treatment on PAH and RV structure and function in this model. Chronic (5 wk) DHEA treatment significantly, but moderately, reduced the severely elevated RV systolic pressure. In contrast, it restored the impaired cardiac index to normal levels, resulting in an improved cardiac function, as assessed by echocardiography. Moreover, DHEA treatment inhibited RV capillary rarefaction, apoptosis, fibrosis, and oxidative stress. The steroid decreased NADPH levels in the RV. As a result, the reduced reactive oxygen species production in the RV of these rats was reversed by NADPH supplementation. Mechanistically, DHEA reduced the expression and activity of Rho kinases in the RV, which was associated with the inhibition of cardiac remodeling-related transcription factors STAT3 and NFATc3. These results show that DHEA treatment slowed the progression of severe PAH in SU5416/hypoxia/normoxia-exposed rats and protected the RV against apoptosis and fibrosis, thus preserving its contractile function. The antioxidant activity of DHEA, by depleting NADPH, plays a central role in these cardioprotective effects.

Brain sigma-1 receptor stimulation improves mental disorder and cardiac function in mice with myocardial infarction.

Mental disorder after myocardial infarction (MI) is reported by many epidemiological studies and is associated with a poor prognosis. The reduction of brain sigma-1 receptor (S1R) plays an important role in the pathogenesis of mental disorder, and we recently demonstrated that the reduction of brain S1R causes sympathoexcitation. However, the role of brain S1R in the association between MI and mental disorder, such as depression or cognitive impairment, remains unclear. To investigate this, we performed left coronary artery ligation on mice to produce an MI model (MI-mice). Compared with sham-operated controls (Sham-mice), MI-mice showed augmented sympathetic activity, decreased cardiac function, and lower S1R expression in both the hypothalamus and hippocampus. Furthermore, MI-mice displayed decreased Y-maze spontaneous alternation (a maker of spatial working memory), decreased circadian variation in locomotor activity, and increased immobility time in the tail suspension test (markers of depression-like behavior). Intracerebroventricular infusion of the S1R agonist PRE084 in MI-mice improved both mental disorder and cardiac function with lowered sympathetic activity and the recovery of the S1R expression in both the hypothalamus and hippocampus. These results indicate that brain S1R is decreased in MI-mice and that this plays an important role in the coexistence of increased heart failure via sympathoexcitation and mental disorders, such as depression or cognitive impairment.

[Ventricular bigeminy as a cause of CRT inefficacy and inappropriate cardioverter-defibrillator intervention]. / Bigeminia komorowa jako przyczyna nieskutecznosci terapii resynchronizujacej i nieadekwatnych interwencji kardiowertera-defibrylatora.

Double counting of ventricular beats is not only one of the cause of an inappropriate detection of ventricular arrhythmias but a reason of lost of resynchronisation therapy. Sensing disturbances often creates the need for reprogramming of the device or additional pharmacotherapy and procedures. We present a case of 76-year-old man with CRT-D and inappropriate detection and intervention due to ventricular bigeminy. Fortunately, change of device program, potassium and magnesium supplementation was successful, without necessity of RF ablation of the ventricular ectopic beats.

Effects of protein kinase C activation on cardiac repolarization and arrhythmogenesis in Langendorff-perfused rabbit hearts.

AIMS: Cardiac arrhythmias are still a major cause of mortality in western countries. Currently available antiarrhythmic drugs are limited by a low efficacy and proarrhythmic effects. The role of the protein kinase C (PKC) signalling pathway in arrhythmogenesis is still unclear. The goal of the present study was to test the effects of PKC stimulation on whole heart electrophysiology and its pro-/antiarrhythmic activity. METHODS AND RESULTS: Left ventricular (LV) action potential duration (APD 90%) was determined in 27 Langendorff-perfused rabbit hearts, using Tyrode solution plus the PKC agonist phorbol-12-myristate-13-acetate (PMA; 100 nM) alone (nine rabbits), Verapamil alone (n = 6), or PMA in combination with Verapamil (0.25 mg/L, six rabbits), or bisindolylmaleimide (0.5 microM, n = 6). Intermittent programmed extra-stimulation was performed to induce ventricular arrhythmias. Administration of PMA alone led to a significant shortening of repolarization (APD 90%, 157 +/- 8 vs. 128 +/- 5 ms, P<0.05). Non-sustained ventricular fibrillation (VF) could be induced in seven out of nine animals. After perfusion of Verapamil (156 +/- 6 vs. 169 +/- 4 ms, P>0.05) or bisindolylmaleimide, a selective inhibitor of PKC (136 +/- 4 vs. 146 +/- 4 ms, P>0.05), PMA-induced shortening of repolarization could be inhibited, and induction of VF failed. Verapamil alone did not affect APD and VF could not be induced. CONCLUSIONS: Activation of PKC facilitates induction of VF, which is most likely due to a shortening of repolarization and a prominent calcium influx. These findings demonstrate involvement of the PKC-signalling pathway in arrhythmogenesis.

Diagnóstico, manejo y tratamiento de la cardiopatía chagásica crónica en áreas donde la infección por Trypanosoma cruzi no es endémica / Diagnosis, management and treatment of chronic Chagas' heart disease in areas where Trypanosoma cruzi infection is not endemic

La enfermedad de Chagas o tripanosomiasis americana es una parasitosis originaria del continente americano. En la naturaleza, Trypanosoma cruzi se transmite vectorialmente a través de diversas especies de chinches triatominos. No obstante, se han descrito otros mecanismos de transmisión no vectorial, como la transmisión a través de productos sanguíneos o mediante el trasplante de órganos infectados, y la transmisión vertical. Actualmente, la enfermedad de Chagas afecta a unos 10-12 millones de personas en el mundo y el proceso de urbanización en América Latina y los movimientos migratorios desde los países endémicos han posibilitado que la enfermedad de Chagas sea diagnosticada en zonas donde la infección no es endémica. Se considera que un 20-30% de las personas infectadas por T. cruzi desarrollarán a lo largo de su vida alteraciones cardiacas. Las características diferenciales de la cardiopatía chagásica, el escaso conocimiento que se tiene de ella en nuestro medio y la elevada frecuencia de arritmias y muerte súbita como primeras manifestaciones potenciales de esta enfermedad hacen prioritarias la elaboración y divulgación de protocolos diagnósticos y terapéuticos para la atención de estos pacientes a fin de mejorar el conocimiento de esta patología por los profesionales sanitarios potencialmente implicados en su detección y manejo

Chagas' disease, or American trypanosomiasis, is a parasitic zoonosis found only in the Americas. Under natural conditions, Trypanosoma cruzi is transmitted by insects belonging to different species of Triatoma. However, several routes of transmission that do not involve insect vectors have also been described, such as transmission via blood products or transplantation of infected organs, and vertical transmission. At present, the number of people infected with Chagas' disease worldwide is estimated to be about 10-12 million. The process of urbanization in Latin America and migratory population movements from endemic countries have led to the disease being diagnosed in non-endemic areas. It is estimated that 20-30% of individuals infected with T. cruzi will develop symptomatic heart disease at some point during their lives. The specific differential characteristics of chronic chagasic cardiopathy, lack of knowledge of the disease among many healthcare workers, and the fact that arrhythmia or sudden death is frequently the first manifestation of disease all make it essential that diagnostic and therapeutic protocols for the disease are developed and disseminated. The aim should be to improve patient care by increasing understanding of the condition by physicians and other healthcare professionals who may be involved in its detection and treatment

Hypocalcemic heart failure in thalassemic patients.

Hypocalcemic cardiomyopathy in primary or secondary hypoparathyroidism is usually refractory to conventional treatment of cardiac failure. We report the case of a thalassemic patient with severe cardiac failure that might have been attributed to several factors, such as hemosiderosis, hypomagnesemia, and hypocalcemia, refractory to conventional cardiac therapy. Cardiac echocardiography showed impaired biventricular performance, and laboratory analyses revealed hypoparathyroidism due to hemosiderosis. When concomitant treatment of heart failure and calcium supplementation was initiated, correction of hypocalcemia resulted in clinical and laboratory improvement, providing strong evidence in support of our hypothesis about hypocalcemic myocardiopathy.

Effects of repeated sauna treatment on ventricular arrhythmias in patients with chronic heart failure.

BACKGROUND: The aim of the present study was to determine whether repeated 60 degrees C sauna treatment improves cardiac arrhythmias in chronic heart failure (CHF) patients, because ventricular arrhythmias are an important therapeutic target in CHF. METHODS AND RESULTS: Thirty patients (59+/-3 years) with New York Heart Association functional class II or III CHF and at least 200 premature ventricular contractions (PVCs)/24 h assessed by 24-h Holter recordings were studied. They were randomized into sauna-treated (n=20) or non-treated (n=10) groups. The sauna-treated group underwent a 2-week program of a daily 60 degrees C far infrared-ray dry sauna for 15 min, followed by 30 min bed rest with blankets, for 5 days per week. Patients in the non-treated group had bed rest in a temperature-controlled room (24 degrees C) for 45 min. The total numbers of PVCs/24 h in the sauna-treated group decreased compared with the non-treated group [848+/-415 vs 3,097+/-1,033/24 h, p<0.01]. Heart rate variability (SDNN, standard deviation of normal-to-normal beat interval) increased [142+/-10 (n=16) vs 112+/-11 ms (n=8), p<0.05] and plasma brain natriuretic peptide concentrations decreased [229+/-54 vs 419+/-110 pg/ml, p<0.05] in the sauna-treated group compared with the non-treated group. CONCLUSION: Repeated sauna treatment improves ventricular arrhythmias in patients with CHF.

Risk stratification for arrhythmic events in patients with idiopathic dilated cardiomyopathy: a review of the literature and current perspectives.

The prognosis for patients with idiopathic dilated cardiomyopathy (DCM) has markedly improved during the last decade, mainly because of advancements in therapeutic strategies. However, sudden death still accounts for a significant part of the total mortality in patients with moderate disease. Recent primary prophylactic trials failed to demonstrate any benefit of cardioverter-defibrillator implantation in an unselected group of idiopathic DCM patients and thus the identification of the subgroup of patients at high arrhythmic risk is crucial. Although different risk stratification methods have been evaluated in risk assessment, the reported clinical value differs in studies, mainly because of differences in either methodology and/or patient selection. The present review focuses on arrhythmic events in idiopathic DCM and on the value of noninvasive methods and electrophysiological study in the risk stratification of this group of patients.

Management of ventricular arrhythmias in adults with congenital heart disease.

The management of ventricular arrhythmias in adults with congenital heart disease is becoming increasingly more important. Ventricular arrhythmias are associated with a number of congenital heart defects (particularly tetralogy of Fallot), and sudden death. A number of invasive and noninvasive methods have been applied to identify those patients at risk, although indications and the prognostic value of these tests are unclear. Treatment of ventricular arrhythmias in this population include antiarrhythmic medications, catheter ablation, surgery, and implantable cardiac defibrillators.

Effects of blood resuscitation versus dextran resuscitation after hemorrhage on intrinsic myocardial function.

BACKGROUND: Myocardial function is altered by many factors present in hemorrhaged and resuscitated animals. The purpose of this study was to determine whether resuscitation after a short period of hemorrhagic shock, which by itself did not alter intrinsic cardiac function, causes dysfunction. METHODS: Guinea pigs were instrumented to measure blood pressure and cardiac output, and several days later 50% of their blood volume was removed at a rate of 1 mL/min. Some animals were resuscitated with the shed blood and some with 6% dextran. Hearts were studied 1 or 24 hours after resuscitation. RESULTS: Isolated hearts from animals after 1 hour of resuscitation demonstrated dysfunction whether resuscitated with blood or dextran, although dysfunction was more severe with blood resuscitation. By 24 hours, dysfunction was essentially reversed. CONCLUSIONS: Resuscitation after hemorrhagic shock caused injury to the myocardium independent of the hemorrhage. Blood resuscitation resulted in greater dysfunction than did resuscitation with dextran.

Adenosine prevents K+-induced Ca2+ loading: insight into cardioprotection during cardioplegia.

In clinical practice, hyperkalemic cardioplegia induces sarcolemmic depolarization, and therefore is used to arrest the heart during open heart operations. However, the elevated concentration of K+ that is present in cardioplegic solutions promotes intracellular Ca2+ loading, which could aggravate ventricular dysfunction after cardiac operations. This review highlights recent findings that have established, at the single cell level, the protective action of adenosine against hyperkalemia-induced Ca2+ loading. When it was added to hyperkalemic cardioplegic solutions, adenosine, at millimolar concentrations and through a direct action on ventricular cardiomyocytes, prevented K+-induced Ca2+ loading. This action of adenosine required the activation of protein kinase C, and it was effective only in cardiomyocytes with low diastolic Ca2+ levels. Of importance, adenosine did not diminish the magnitude of K+-induced membrane depolarization, allowing unimpeded cardiac arrest. Taken together, these findings provide direct support for the idea that adenosine is valuable when used as an adjunct to hyperkalemic cardioplegia. This idea has emerged from previous clinical studies that have shown improvement of the clinical outcome after cardiac operations when adenosine or related substances were used to supplement cardioplegic solutions. Further studies are required to define more precisely the mechanism of action of adenosine, and the conditions that may determine the efficacy of adenosine as a cytoprotective supplement to cardioplegia.

[Ventricular pre-excitation in Wolff Parkinson White syndrome in the aged]. / La pre-eccitazione ventricolare da sindrome di Wolff Parkinson white nell'anziano.

AIM: To evaluate any differences in ventricular pre-excitation secondary to Wolff Parkinson White syndrome in the aged compared to young and adult patients. EXPERIMENTAL DESIGN: a clinical study was performed using a comparative prospective criterion with retrospective analysis. The duration of follow-up ranged between one and ten years. SETTING: the series was collected from the Cardiology Clinic of the Health District and the Cardiology Division of Gorizia, both forming part of no. 2 Isontina Health Service. PATIENTS OR PARTICIPANTS: the series included 17 patients suffering from Wolff Parkinson White syndrome who were divided into two study groups: 9 elderly patients and 8 young patients. The latter were subdivided into a first subgroup of 4 cases with Wolff Parkinson White syndrome with ECG positive for the presence of delta waves, and a second subgroup also with Wolff Parkinson White syndrome secondary to bundle. INTERVENTIONS: some young patients with Wolff Parkinson White syndrome who were symptomatic for tachycardia underwent ablative surgery with radiofrequency of the bundle. PARAMETERS: all patients underwent cardiological screening focused in particular on surface electrocardiogram. Those cases with Wolff-Parkinson White syndrome with occult bundle underwent transesophageal electrostimulation to find the conduction threshold of the anomalous bundle. RESULTS: Adult-elderly patients: six subjects were diagnosed with antero-septal and left ventricular Kent's bundle (type B common) and 3 cases with Mahaim-Wiston bundle (type A rare). Surface ECG revealed the presence of left ventricular hypertrophy in 6 cases, left anterior hemiblock and total block of the left branch in 3 cases, as well as myocardial pseudonecrosis correlated to Wolff Parkinson White syndrome. Young patients: four out of this group were affected by Kent's bundle with type B Wolff Parkinson White syndrome and the same number suffered from the same syndrome caused by occult bundle. Patients in the first subgroup showed an antero-septal, transitional and left ventricular orientation of Kent's bundle, with the onset of 2 cases of orthodromic and antidromic reciprocal rhythm respectively and 1 case of atrial fibrillation. The refractory nature of the anomalous pathway was not very high in 2 cases, equal to 60 milliseconds and 240 milliseconds with the proposed ablation of the anomalous bundle.

A moderate transfusion regimen may reduce iron loading in beta-thalassemia major without producing excessive expansion of erythropoiesis.

BACKGROUND: Hypertransfusion with a baseline hemoglobin of 10 to 12 g per dL is still considered by many to be the mainstay of conservative therapy for beta-thalassemia major. However, this regimen is frequently associated with manifestations of transfusion iron overload, despite regular chelation therapy with subcutaneous desferoxamine. STUDY DESIGN AND METHODS: To verify whether a transfusion regimen with a target pretransfusion hemoglobin level between 9 and 10 g per dL can allow a significant reduction in blood consumption, while still effectively suppressing erythropoiesis, the records were reviewed of 32 beta-thalassemia major patients, who were maintained at a pretransfusion hemoglobin of 11.3 +/- 0.5 g per dL between 1981 and 1986. These patients were switched at the beginning of 1987 to a transfusion regimen with pretransfusion hemoglobin of 9.4 +/- 0.4 g per dL. The degree of erythroid marrow activity was evaluated in these patients and in 32 subjects with beta-thalassemia intermedia through the simple measurement of serum transferrin receptor. RESULTS: After the adoption of the moderate transfusion regimen, transfusion requirements decreased from 137 +/- 26 to 104 +/- 23 mL per kg per year of red cells (p < 0.0001), and mean serum ferritin decreased from 2448 +/- 1515 to 1187 +/- 816 micrograms per L (p < 0.0001), with one-half of patients achieving serum ferritin levels lower than 1000 micrograms per L. The proportion of patients having spontaneous pubertal development increased significantly (p < 0.01), as a result of less iron-related gonadotropin insufficiency. At the lower pretransfusion hemoglobin, erythroid marrow activity did not exceed two to three times normal levels in most subjects. CONCLUSION: As compared with hypertransfusion, moderate transfusion may allow more effective prevention of iron loading, with higher likelihood of spontaneous pubertal development and without producing excessive expansion of erythropoiesis.