Documento de consenso de la Sociedad Española de Anestesiología y Reanimación (SEDAR) y la Sociedad Española de Medicina de Urgencias y Emergencias (SEMES) para la adquisición de competencias y obtención del diploma acreditativo en el uso de la Ecocardiografía básica en Cuidados Intensivos y Urgencias / Diploma on Basic Echocardiography training and competencies for Intensive Care and Emergency medicine: Consensus document of the Spanish Society of Anesthesiology and Critical Care (SEDAR) and the Spanish Society of Emergency Medicine (SEMES)

El uso de la ecocardiografía a pie de cama se ha convertido en una herramienta indispensable en la monitorización hemodinámica y diagnóstico en el paciente crítico. Su conocimiento, manejo e indicaciones requieren por parte de las sociedades científicas una implicación para una formación reglada que capacite al profesional. El grupo de trabajo de Ecografía Clínica en Cuidados Intensivos de la Sociedad Española de Anestesiología y Reanimación (SEDAR) y el grupo de trabajo de Ecografía Clínica de la Sociedad Española de Medicina de Urgencias y Emergencias (SEMES) han desarrollado un documento de consenso en el que se definen los objetivos de aprendizaje y los requisitos necesarios para adquirir las competencias recomendadas en relación con el uso de la Ecocardiografía básica en Cuidados Intensivos y Urgencias, y así poder obtener un diploma acreditativo en Ecocardiografía básica en Cuidados Intensivos y Urgencias. En este documento se definen las competencias y el programa de formación para alcanzar el nivel básico en Ecocardiografía en Cuidados Intensivos y Urgencias, como parte del Diploma Completo en Ecografía en Cuidados Intensivos y Urgencias de la SEDAR y SEMES. La Sociedad Española de Anestesiología y Reanimación (SEDAR), junto con la Sociedad Española de Medicina Interna (SEMI) y la Sociedad Española de Medicina de Urgencias y Emergencias (SEMES), ha desarrollado un documento de consenso determinando las competencias y un programa formativo para la adquisición de un diploma en ecografía (pulmonar, vascular y abdominal) en Cuidados Intensivos y Urgencias. Solo cuando se obtenga el Diploma en Ecocardiografía básica y el Diploma en Ecografía pulmonar, vascular, abdominal de la SEDAR, SEMI y SEMES se podrá adquirir el Diploma Completo de Ecografía en Cuidados Intensivos y Urgencias de la SEDAR y SEMES.(AU)

Cardiac ultrasound has become an essential tool for diagnosis and hemodynamic monitoring in critically ill patients. Scientific societies need to work toward developing a training program that will allow clinicians to acquire competence in performing cardiac ultrasound and understanding its indications. The Clinical Ultrasound for Intensive Care task force of the Spanish Society of Anesthesiology and Critical Care (SEDAR) and the Spanish Society of Emergency Medicine (SEMES) have drawn up this position statement defining the learning objectives and training required to acquire the competencies recommended for basic ultrasound management in the intensive care and emergency setting in order to obtain a diploma in Basic Ultrasound in Intensive Care and Emergency Medicine. This document defines the training program and the competencies needed for basic skills in ultrasound in Intensive Care and Emergency Medicine - part of the Diploma in Ultrasound for Intensive Care and Emergency Medicine awarded by SEDAR/SEMES. The Spanish Society of Anesthesia (SEDAR), Spanish Society of Internal Medicine (SEMI) and Spanish Society of Emergency Medicine (SEMES) have drawn up a position statement determining the competencies and training program for a diploma in ultrasound (lung, abdominal and vascular) in Intensive Care and Emergency Medicine. To obtain the SEDAR/SEMES Diploma in Ultrasound in Intensive Care and Emergency Medicine, clinicians must have completed the SEDAR, SEMI and SEMES Diploma in basic ultrasound and the Diploma in lung, abdominal, and vascular ultrasound.(AU)

Diploma on Basic Echocardiography training and competencies for Intensive Care and Emergency medicine: Consensus document of the Spanish Society of Anesthesiology and Critical Care (SEDAR) and the Spanish Society of Emergency Medicine (SEMES).

Cardiac ultrasound has become an essential tool for diagnosis and hemodynamic monitoring in critically ill patients. Scientific societies need to work toward developing a training program that will allow clinicians to acquire competence in performing cardiac ultrasound and understanding its indications. The Clinical Ultrasound for Intensive Care task force of the Spanish Society of Anesthesiology and Critical Care (SEDAR) and the Spanish Society of Emergency Medicine (SEMES) have drawn up this position statement defining the learning objectives and training required to acquire the competencies recommended for basic ultrasound management in the intensive care and emergency setting in order to obtain a diploma in Basic Ultrasound in Intensive Care and Emergency Medicine. This document defines the training program and the competencies needed for basic skills in ultrasound in Intensive Care and Emergency Medicine-part of the Diploma in Ultrasound for Intensive Care and Emergency Medicine awarded by SEDAR/SEMES. The Spanish Society of Anesthesia (SEDAR), Spanish Society of Internal Medicine (SEMI) and Spanish Society of Emergency Medicine (SEMES) have drawn up a position statement determining the competencies and training program for a diploma in ultrasound (lung, abdominal and vascular) in Intensive Care and Emergency Medicine. To obtain the SEDAR/SEMES Diploma in Ultrasound in Intensive Care and Emergency Medicine, clinicians must have completed the SEDAR, SEMI and SEMES Diploma in basic ultrasound and the Diploma in lung, abdominal, and vascular ultrasound.

Depression and suicidal ideation in Mexican medical students during COVID-19 outbreak. A longitudinal study.

INTRODUCTION: The COVID-19 pandemic has been particularly difficult for populations at risk for mental health problems, such as healthcare professionals and medical students. In the present study, we evaluated the effect of the pandemic on mental health in a sample of Mexican medical students with and without a mental health diagnosis. METHOD: Longitudinal and descriptive study based on scales of suicidal ideation, depressive symptoms and risk of alcohol consumption, conducted in April and December 2020. RESULTS: Sample includes 247 medical students, 64.4% are women. Prevalence of depression increased between April and December from 19.84% to 40.08%. In the case of women from 23.67% to 42.60% (χ2 = 0.000) and in men from 11.54% to 34.62% (χ2 = 0.001). In April 16.92% of healthy students presented some sign of depression and in December the percentage increased to 40.80% (χ2 = 0.000). Regarding medicated students, the prevalence in April was 32.61% and in December it was 36.96% (χ2 = 0.662). In April, the medicated students with risk of suicidal ideation were 17 out of 46 (36.96%), compared to the students without a diagnosis of psychiatric illness were 29 out of 201 (13.43%) (χ2 = 0.000). For December, the non-medicated students at risk of suicidal ideation were 34 out of 201 (16.91%), and the medicated students were 12 out of 46 (26.09%) (χ2 = 0.149). CONCLUSIONS: The pandemic has increase the rate of depression in medical students, being more severe in women. Students under psychiatric treatment showed a higher prevalence of depression; however, the fact of being under treatment resulted in a protective factor for the increase in the prevalence of depression. It is important to deepen the understanding of the causes of depression and to disseminate among the university community the benefits of early detection and treatment of people with socio-emotional disorders.

Documento de consenso de la Sociedad Española de Anestesiología y Reanimación (SEDAR), Sociedad Española de Medicina Interna (SEMI) y Sociedad Española de Medicina de Urgencias y Emergencias (SEMES) para la definición de competencias mínimas de ecografía en Cuidados Intensivos y Urgencias y la obtención del Diploma acreditativo / Diploma on Ultrasound training and competency for Intensive Care and Emergency Medicine: Consensus document of the Spanish Society of Anesthesia (SEDAR), Spanish Society of Internal Medicine (SEMI) and Spanish Society of Emergency Medicine (SEMES)

El uso de la ecografía como herramienta de diagnóstico clínico y guía de procedimientos a pie de cama se ha convertido en un examen indispensable en los cuidados del paciente agudo. La capacitación de los profesionales en unas competencias mínimas de conocimiento, manejo e indicaciones de uso requieren de una formación reglada definida por las Sociedades Científicas. El grupo de trabajo de Ecografía en Cuidados Intensivos de la Sociedad Española de Anestesiología y Reanimación (SEDAR), de la Sociedad Española de Medicina Interna (SEMI) y la Sociedad Española de Medicina de Urgencias y Emergencias (SEMES) ha desarrollado este documento de consenso en el que se define el programa de formación y las competencias mínimas recomendadas a adquirir con relación al uso de la Ecografía en Cuidados Intensivos, Anestesia, Urgencias y Emergencias. En este documento se definen el programa de formación y las competencias a adquirir para alcanzar el diploma acreditativo en ecografía toraco-pulmonar, ecografía abdominal y ecografía vascular. Este documento puede servir de guía para definir las competencias a adquirir en los programas de formación de médicos internos residentes (MIR) de los especialistas que trabajen en cuidados intensivos, anestesia, urgencias y emergencias.(AU)

The use of ultrasound as a clinical diagnostic tool and guide of bedside procedures has become an indispensable examination in the acute critically ill patient. The training of professionals in minimum skills of knowledge, management and indications of use of ultrasound required to be defined by the Scientific Societies. The Intensive Care Ultrasound Working Group of the Spanish Society of Anesthesiology and Resuscitation (SEDAR), of the Spanish Society of Internal Medicine (SEMI) and the Spanish Society of Emergency Medicine (SEMES) has developed this consensus document in which the recommended training program and the minimum competencies to be achieved with regard to the use of Ultrasound in Intensive Care, Anesthesia and Emergency medicine are defined. This document defines the training program and the skills to acquire in order to achieve the diploma in lung, abdominal and vascular ultrasound. This document can serve as a guide to define the skills to be acquired in the training programs of residents (MIRs) of specialists working in intensive care, anesthesia, and emergency medicine.(AU)

Analysis of phenanthrene degradation by Ascomycota fungi isolated from contaminated soil from Reynosa, Mexico.

Polycyclic aromatic hydrocarbons (PAHs) are organic compounds generated mainly by anthropogenic sources. They are considered toxic to mammals, since they have carcinogenic, mutagenic and genotoxic properties, among others. Although mycoremediation is an efficient, economical and eco-friendly technique for degrading PAHs, the fungal degradation potential of the phylum Ascomycota has not been widely studied. In this work, we evaluated different fungal strains from the polluted soil of 'La Escondida' lagoon in Reynosa, Mexico to know their potential to degrade phenanthrene (PHE). Forty-three soil isolates with the capacity to grow in the presence of PHE (0·1% w/v) were obtained. The fungi Aspergillus oryzae MF13 and Aspergillus flavipes QCS12 had the best potential to degrade PHE. Both fungi germinated and grew at PHE concentrations of up to 5000 mg l-1 and degraded 235 mg l-1 of PHE in 28 days, with and without an additional carbon source. These characteristics indicate that A. oryzae MF13 and A. flavipes QCS12 could be promising organisms for the remediation of sites contaminated with PAHs and detoxification of recalcitrant xenobiotics.

Diploma on Ultrasound training and competency for Intensive Care and Emergency Medicine: Consensus document of the Spanish Society of Anesthesia (SEDAR), Spanish Society of Internal Medicine (SEMI) and Spanish Society of Emergency Medicine (SEMES). / Documento de consenso de la Sociedad Española de Anestesiología y Reanimación (SEDAR), Sociedad Española de Medicina Interna (SEMI) y Sociedad Española de Medicina de Urgencias y Emergencias (SEMES) para la definición de competencias mínimas de ecografía en Cuidados Intensivos y Urgencias y la obtención del Diploma acreditativo.

The use of ultrasound as a clinical diagnostic tool and guide of bedside procedures has become an indispensable examination in the acute critically ill patient. The training of professionals in minimum skills of knowledge, management and indications of use of ultrasound required to be defined by the Scientific Societies. The Intensive Care Ultrasound Working Group of the Spanish Society of Anesthesiology and Resuscitation (SEDAR), of the Spanish Society of Internal Medicine (SEMI) and the Spanish Society of Emergency Medicine (SEMES) has developed this consensus document in which the recommended training program and the minimum competencies to be achieved with regard to the use of Ultrasound in Intensive Care, Anesthesia and Emergency medicine are defined. This document defines the training program and the skills to acquire in order to achieve the diploma in lung, abdominal and vascular ultrasound. This document can serve as a guide to define the skills to be acquired in the training programs of residents (MIRs) of specialists working in intensive care, anesthesia, and emergency medicine.

Greenhouse gas emissions and energy efficiencies for soybeans and maize cultivated in different agronomic zones: A case study of Argentina.

Of all human activities, agriculture has one of the highest environmental impacts, particularly related to Greenhouse Gas (GHG) emissions, energy use and land use change. Soybean and maize are two of the most commercialized agricultural commodities worldwide. Argentina contributes significantly to this trade, being the third major producer of soybeans, the first exporter of soymeal and soybean oil, and the third exporter of maize. Despite the economic importance of these crops and the products derived, there are very few studies regarding GHG emissions, energy use and efficiencies associated to Argentinean soybean and maize production. Therefore, the aim of this work is to determine the carbon and energy footprint, as well as the carbon and energy efficiencies, of soybeans and maize produced in Argentina, by analyzing 18 agronomic zones covering an agricultural area of 1.53millionkm2. Our results show that, for both crops, the GHG and energy efficiencies at the Pampean region were significantly higher than those at the extra-Pampean region. The national average for production of soybeans in Argentina results in 6.06ton/ton CO2-eq emitted to the atmosphere, while 0.887ton of soybean were produced per GJ of energy used; and for maize 5.01ton/ton CO2-eq emitted to the atmosphere and 0.740ton of maize were produced per each GJ of energy used. We found that the large differences on yields, GHGs and energy efficiencies between agronomic regions for soybean and maize crop production are mainly driven by climate, particularly mean annual precipitation. This study contributes for the first time to understand the carbon and energy footprint of soybean and maize production throughout several agronomic zones in Argentina. The significant differences found in the productive efficiencies questions on the environmental viability of expanding the agricultural frontier to less suitable lands for crop production.

Distribution of angiotensin type 1a receptor-containing cells in the brains of bacterial artificial chromosome transgenic mice.

In the central nervous system, angiotensin II (AngII) binds to angiotensin type 1 receptors (AT(1)Rs) to affect autonomic and endocrine functions as well as learning and memory. However, understanding the function of cells containing AT(1)Rs has been restricted by limited availability of specific antisera, difficulties discriminating AT(1)R-immunoreactive cells in many brain regions and, the identification of AT(1)R-containing neurons for physiological and molecular studies. Here, we demonstrate that an Agtr1a bacterial artificial chromosome (BAC) transgenic mouse line that expresses type A AT(1)Rs (AT1aRs) identified by enhanced green fluorescent protein (EGFP) overcomes these shortcomings. Throughout the brain, AT1aR-EGFP was detected in the nuclei and cytoplasm of cells, most of which were neurons. EGFP often extended into dendritic processes and could be identified either natively or with immunolabeling of GFP. The distribution of AT1aR-EGFP cells in brain closely corresponded to that reported for AngII binding and AT1aR protein and mRNA. In particular, AT1aR-EGFP cells were in autonomic regions (e.g., hypothalamic paraventricular nucleus, central nucleus of the amygdala, parabrachial nucleus, nuclei of the solitary tract and rostral ventrolateral medulla) and in regions involved in electrolyte and fluid balance (i.e., subfornical organ) and learning and memory (i.e., cerebral cortex and hippocampus). Additionally, dual label electron microscopic studies in select brain areas demonstrate that cells containing AT1aR-EGFP colocalize with AT(1)R-immunoreactivity. Assessment of AngII-induced free radical production in isolated EGFP cells demonstrated feasibility of studies investigating AT1aR signaling ex vivo. These findings support the utility of Agtr1a BAC transgenic reporter mice for future studies understanding the role of AT(1)R-containing cells in brain function.

Immunohistochemical analysis of Ki-67, p21waf1/cip1 and apoptosis in marker lesions from patients with superficial bladder tumours treated with vinorelbine intravesical therapy in a preliminary phase I trial.

OBJECTIVE: To investigate Ki-67 and p21Waf1/Cip1 expression and apoptosis, before and after treatment, in tumour biopsies obtained from patients with superficial bladder cancer who underwent vinorelbine intravesical therapy. PATIENTS AND METHODS: Twenty patients with high-risk superficial bladder cancer (including one or more of the following parameters: tumour diameter > 3 cm, histological grade 3, or multicentric tumours) were treated 1-6 times (weekly) with intravesical vinorelbine (50 mg/mL) instillations. Transurethral tumour marker biopsies were obtained one week before the first instillation of the drug and one week after the last. The biopsies were immunostained for Ki-67 and p21Waf1/Cip1 with monoclonal antibodies, on tissue sections derived from paraffin-embedded samples obtained before and after vinorelbine treatments. In addition, apoptosis was determined using a terminal deoxynucleotidyl transferase-mediated dUTP biotin nick-end labelling (TUNEL) technique. RESULTS: There were no significant differences in the cell proliferation marker Ki-67 in biopsies taken before or after treatment. However, p21Waf1/Cip1 showed significantly higher expression in biopsies obtained after vinorelbine treatment, with median (range) values of 40 (20-90)% before and 70 (50-80)% after (P < 0.001, paired nonparametric Wilcoxon test). The apoptotic index was significantly higher after vinorelbine therapy, with median (range) values of 0.89 (0.06-3.8)% before and 2.25 (0.17-18.7)% after treatment (P < 0.001, paired nonparametric Wilcoxon test). Despite the brief treatment and few patients there was a clinical response in nine patients, together with low toxicity in all. CONCLUSION: The intravesical treatment of tumours with vinorelbine affects p21Waf1/Cip1 expression without blocking cell proliferation, although increasing apoptosis. The preliminary results suggest that vinorelbine may be useful for treating superficial bladder tumours, and thus a phase II study is warranted.

Differential anthracycline sensitivity in two related human colon carcinoma cell lines expressing similar levels of P-glycoprotein.

Chemosensitivity of the human colon carcinoma HCT-15 cell line to 4'-epidoxorubicin proved to be 100-fold higher than that of its variant HCT-15 EDR. Confocal scanning microscopy showed significant less drug accumulation in HCT-15 EDR. A 2-fold increase in hsp27 expression was found in HCT-15 EDR, with no alteration in hsp70. The expression of the drug exporter Pgp was similar in both cell lines, despite the lower drug accumulation shown by HCT-15 EDR in respect to HCT-15. Other molecules implicated in the acquisition of enhanced chemoresistance or a more active Pgp variant present in HCT-15 EDR, could explain the phenomenon.

Mechanism of antimetastatic immunopotentiation by low-dose cyclophosphamide.

We have previously reported the antimetastatic effect of a single low-dose of cyclophosphamide (Cy) on L-TACB rat lymphoma. The phenomenon could be adoptively transferred in immunocompetent rats and is abolished in nude mice, facts for which an immunomodulatory explanation was proposed. The aim of this paper was to identify the mechanism(s) by which spleen cells from Cy-treated tumour-bearing rats could exert this antimetastatic activity. Conditioned media obtained by incubation of spleen cells from Cy-treated and non-treated tumour-bearing rats, under specific or non-specific stimulation, were assayed to evaluate their effect on lymphocyte proliferation. The production of transforming growth factor beta (TGF-beta), interleukin-10 (IL-10) and nitric oxide (NO) by conditioned media was also studied. The restoration of spleen lymphoproliferative responses to normal levels when exposed to media conditioned by splenocytes from Cy-treated tumour-bearing rats, together with a decreased production of suppressive cytokines TGF-beta, IL-10 and NO, suggest an enhancement of host antimetastatic immunity triggered by single low-dose Cy treatment.

OCI-5/GPC3, a glypican encoded by a gene that is mutated in the Simpson-Golabi-Behmel overgrowth syndrome, induces apoptosis in a cell line-specific manner.

OCI-5/GPC3 is a member of the glypican family. Glypicans are heparan sulfate proteoglycans that are bound to the cell surface through a glycosyl-phosphatidylinositol anchor. It has recently been shown that the OCI-5/GPC3 gene is mutated in patients with the Simpson-Golabi-Behmel Syndrome (SGBS), an X-linked disorder characterized by pre- and postnatal overgrowth and various visceral and skeletal dysmorphisms. Some of these dysmorphisms could be the result of deficient growth inhibition or apoptosis in certain cell types during development. Here we present evidence indicating that OCI-5/GPC3 induces apoptosis in cell lines derived from mesothelioma (II14) and breast cancer (MCF-7). This induction, however, is cell line specific since it is not observed in NIH 3T3 fibroblasts or HT-29 colorectal tumor cells. We also show that the apoptosis-inducing activity in II14 and MCF-7 cells requires the anchoring of OCI-5/GPC3 to the cell membrane. The glycosaminoglycan chains, on the other hand, are not required. MCF-7 cells can be rescued from OCI-5/GPC3-induced cell death by insulin-like growth factor 2. This factor has been implicated in Beckwith-Wiedemann, an overgrowth syndrome that has many similarities with SGBS. The discovery that OCI-5/GPC3 is able to induce apoptosis in a cell line- specific manner provides an insight into the mechanism that, at least in part, is responsible for the phenotype of SGBS patients.

Mitochondrial import and processing of rat liver carnitine palmitoyltransferase II defines the amino terminus of the mature protein. Possibility of differential modification of the rat and human isoforms.

[35S]Methionine-labeled porcine heart citrate synthase (used here as a positive control) and rat liver carnitine palmitoyltransferase II (CPT II) were generated by in vitro transcription and translation of their cDNA constructs in appropriate Bluescript plasmids. Each product was imported into rat liver mitochondria in an energy-dependent manner to yield an immunoprecipitable protein of smaller size that comigrated with the corresponding purified enzyme. The size shift occurring with citrate synthase was consistent with the removal of the postulated 27-amino acid leader peptide. To determine the amino terminus of mature CPT II, [35S]methionine- or [3H]leucine-labeled material (after import and processing) was subjected to Edman degradation, followed by counting of the radioactivity released on each cycle. The results established that the precursor targeting peptide was cleaved between leucine 25 and serine 26 in the previously deduced amino acid sequence. Taken in conjunction with the recent report of Finocchiaro et al. (Finocchiaro, G., Taroni, F., Rocchi, M., Martin, A. L., Colombo, I., Tarelli, G. T., and DiDonato, S. (1991) Proc. Natl. Acad. Sci. U.S.A. 88, 661-665), the present results establish three key points concerning the rat and human forms of CPT II. First, it appears that in both species the initial translation product contains 658 amino acids and, upon mitochondrial import, is reduced in length by 25 residues through cleavage at an identical site. Second, the difference in electrophoretic mobility between the two mature proteins (documented earlier) presumably reflects either anomalous behavior of one of them on polyacrylamide gels or differential covalent modification. Finally, the recent suggestion by Brady et al. (Brady, P. S., Liu, J. S., Park, E. A., Hanson, R. W., and Brady, L. J. (1991) FASEB J. 5, A817) that our CPT II cDNA construct is incomplete in the 5'-coding region is refuted.

Diagnostic implications of atrial vulnerability.

Extrastimulation in the atrial vulnerable zone may result in atrial fibrillation or flutter (AFF), especially with stimulation of multiple atrial sites. However, the clinical relevance of such vulnerability to AFF is unknown. Therefore, single twice-threshold extrastimuli were applied at three disparate right atrial sites in 45 consecutive unmedicated patients without overt heart failure. Group I consisted of 12 patients with documented spontaneous paroxysms of AFF. AFF was duplicated in 9 to 12 patients using extrastimulation in the vulnerable zone (5 in sinus rhythm, 4 requiring atrial pacing at 120 beats/min). Group II consisted of 33 patients without documented AFF dispite monitoring. Vulnerability to AFF was found in 12 of 33 patients (4 in sinus rhythm, 8 requiring atrial pacing). The duration of induced AFF did not discriminate between the two groups. Among the 12 Group II patients vulnerable to AFF, 3 had rapid palpitations, 2 had undiagnosed rapid tachycardias, 1 had atrial tachycardias and 1 junctional tachycardias. In vulnerable patients, the pause after AFF correlated with the pause after atrial pacing, but only 1 of 11 Group II patients with sick sinus syndrome was vulnerable. Thus, paroxysmal AFF may be duplicated with the extrastimulus technique if sufficient arial sites are stimulated, providing a model for evaluation of these arrhythmias. But atrial vulnerability, even to extrastimulation at normal heart rates, may be seen in patients suspected of atrial tachyarrhythmia in the absence of documented AFF, and does not contribute to the diagnosis of sinoatrial dysfunction.

Effects of digitalis on atrial vulnerability.

The effects of digitalis on vulnerability to atrial fibrillation and flutter were assessed in man, using the model of repetitive atrial firing initiated by post-drive atrial extrastimulation. Nine patients without heart failure or significant mitral valve disease were tested before and 30 minutes after the administration of 0.01 mg/kg ouabain. When repetitive firing was manifested by flutter, neither the flutter cycle length nor the interval from the initiating beat to the first flutter beat was consistently altered by ouabain. Repetitive firing was found at the atrial site with the shortest functional refractory period. The vulnerable zone bordered this refractory period. The functional refractory period was lengthened after ouabain, from 231 +/- 13 to 246 +/- 15 msec (mean +/- standard error of the mean) (P less than 0.025). Partly because of prolonged refractoriness, the vulnerable zone was curtailed by ouabain, from 32.2 +/- 5.7 to 9.4 +/- 4.6 msec (P less than 0.001). This result suggests a protective effect of digitalis against atrial fibrillation and flutter independent of its hemodynamic actions.

Electrophysiologic effects of hydralazine on sinoatrial function in patients with sick sinus node syndrome.

The electrophysiologic effects of hydralazine were evaluated in nine hypertensive patients with sinoatrial dysfunction. Intravenous hydralazine, 0.15 mg/kg, caused no significant reduction in arterial blood pressure. Yet this dose of hydralazine increased heart rate from 61.9 +/- 4.1 beats/min (mean +/- standard error of the mean) to 68.6 +/- 4.9 (P less than 0.001). Sinus nodal recovery time upon termination of atrial pacing shortened from 3,207 +/- 1,098 to 2,064 +/- 573 msec (P less than 0.05) and second escape cycles shortened as well (P less than 0.025). Acceleration of heart rate and abbreviation of recovery time did not closely correlate with change in blood pressure (r = 0.41 and 0.18, respectively). Junctional escape beats became more frequent and junctional escape time shortened from 2,525 +/- 692 to 1,705 +/- 382 msec (P less than 0.05). Sinoatrial conduction time tended to shorten, but a significant change was not observed. Atrial tachyarrhythmias did not occur and atrial refractoriness was unchanged. Thus, a minimal blood pressure response to hydralazine was associated with enhanced automaticity. Hydralazine merits clinical trial for treatment of sick sinus syndrome with concomitant hypertension.