Assuntos
Doenças Cardiovasculares/fisiopatologia , Diabetes Mellitus Tipo 2/fisiopatologia , Resistência à Insulina/fisiologia , Animais , Diabetes Mellitus Tipo 2/complicações , Endotélio Vascular/fisiologia , Metabolismo Energético , Glucose/metabolismo , Coração/fisiologia , Humanos , Insulina/fisiologia , Músculo Esquelético/fisiologia , Isquemia Miocárdica/etiologia , Isquemia Miocárdica/fisiopatologia , Miocárdio/metabolismoRESUMO
Currently, the transradial approach to cardiac catheterization and interventions is becoming a more popular method of access in the United States. Although the radial access site is not new (the approach dates back to the 1940s), it has only in the last few years become more widespread. This article provides the expert and advanced practice nurse with an understanding of the transradial approach to catheterization and percutaneous coronary interventions. The following aspects are discussed: the historical perspective, the technique, the nursing care and potential complications of the transradial approach, as well as the future directions for nursing and medical practice.
Assuntos
Cateterismo Cardíaco/métodos , Cateterismo Cardíaco/enfermagem , Humanos , Artéria Radial , Especialidades de Enfermagem/métodos , Punho/irrigação sanguíneaRESUMO
Therapeutic mediastinal radiation predisposes patients to an increased risk of developing premature coronary artery disease. Other structures surrounding the heart within the radiation field are also susceptible to injury. This case report highlights the importance of recognizing concurrent damage to the internal mammary artery that, in this particular group of patients, may not be the ideal arterial conduit for coronary artery bypass surgery.
Assuntos
Doença das Coronárias/etiologia , Doença das Coronárias/cirurgia , Vasos Coronários/efeitos da radiação , Anastomose de Artéria Torácica Interna-Coronária , Adulto , Braquiterapia , Angiografia Coronária , Doença das Coronárias/radioterapia , Doença de Hodgkin/radioterapia , Humanos , Masculino , Mediastino , Radioterapia/efeitos adversos , Dosagem Radioterapêutica , Recidiva , ReoperaçãoRESUMO
The purpose of the present study was to evaluate a novel approach for determining skeletal muscle-specific glucose flux using radioactive stereoisomers and the microdialysis technique. Microdialysis probes were inserted into the vastus lateralis muscle of human subjects and perfused (4 microl/min) with a Ringer solution containing small amounts of radioactive D- and L-glucose as the internal reference markers for determining probe recovery as well as varying concentrations of insulin (0-10 microM). The rationale behind this approach was that both stereoisomers would be equally affected by the factors that determine probe recovery, with the exception of L-glucose, which is nonmetabolizable and would not be influenced by tissue uptake. Therefore, any differences in the probe recovery ratios between the D- and L-stereoisomers represent changes in skeletal muscle glucose uptake directly at the tissue level. There were no differences in probe recovery between the D- (42.3 +/- 3.5%) and L- (41.2 +/- 3.5) stereoisomers during the control period (no insulin), which resulted in a D/L ratio of 1.04 +/- 0.03. However, during insulin perfusion (1 microM), The D/L ratio increased to 1.62 +/- 0.08 and 1.58 +/- 0.07 (P < 0.05) during the two collection (0-15 and 15-30 min) periods, respectively. This was accomplished solely by an increase (P < 0.05) in D-glucose probe recovery, as L-glucose probe recovery remained unchanged. In a second set of experiments, the perfusion of 10 microM insulin did not increase the D/L ratio (1.40 +/- 0.11) above that observed during 1.0 microM (1.41 +/- 0.07) insulin perfusion. These data suggest that this method is sufficiently sensitive to detect differences in insulin-stimulated glucose uptake; thus the use of radioactive stereoisomers in conjunction with the microdialysis technique provides a novel and useful technique for determining tissue-specific glucose flux and insulin sensitivity.
Assuntos
Radioisótopos de Carbono , Glucose/farmacocinética , Microdiálise/métodos , Músculo Esquelético/metabolismo , Trítio , Adulto , Transporte Biológico/efeitos dos fármacos , Transporte Biológico/fisiologia , Feminino , Humanos , Hipoglicemiantes/administração & dosagem , Insulina/administração & dosagem , Masculino , PerfusãoRESUMO
The world of interventional cardiology has changed dramatically since the advent of balloon angioplasty. New therapies have evolved over the past decade as knowledge of the pathophysiology of heart disease has increased. Nurses who have an understanding of this pathophysiology will be better equipped to manage and educate their patients, teaching them about current and future interventional therapies. This article reviews the pathophysiology of heart disease, current interventional therapies, and the future directions for interventional cardiology nursing practice.
Assuntos
Cardiologia/tendências , Cardiopatias , Stents , Angioplastia com Balão/tendências , Arteriosclerose/fisiopatologia , Cardiopatias/diagnóstico , Cardiopatias/enfermagem , Cardiopatias/fisiopatologia , Cardiopatias/terapia , Humanos , Stents/estatística & dados numéricos , Stents/tendênciasRESUMO
We compared reflex responses to static handgrip at 30% maximal voluntary contraction (MVC) in 10 women (mean age 24.1 +/- 1.7 yr) during two phases of their ovarian cycle: the menstrual phase (days 1-4) and the follicular phase (days 10-12). Changes in muscle sympathetic nerve activity (MSNA; microneurography) in response to static exercise were greater during the menstrual compared with follicular phase (phase effect P = 0.01). Levels of estrogen were less during the menstrual phase (75 +/- 5.5 vs. 116 +/- 9.6 pg/ml, days 1-4 vs. days 10-12; P = 0.002). Generated tension did not explain differences in MSNA responses (MVC: 29.3 +/- 1.3 vs. 28.2 +/- 1.5 kg, days 1-4 vs. days 10-12; P = 0.13). In a group of experiments with the use of 31P-NMR spectroscopy, no phase effect was observed for H+ and H2PO-4 concentrations (n = 5). During an ischemic rhythmic handgrip paradigm (20% MVC), a phase effect was not observed for MSNA or H+ or H2PO-4 concentrations, suggesting that blood flow was necessary for the expression of the cycle-related effect. The present studies suggest that, during static handgrip exercise, MSNA is increased during the menstrual compared with the follicular phase of the ovarian cycle.
Assuntos
Exercício Físico/fisiologia , Ciclo Menstrual/fisiologia , Sistema Nervoso Simpático/fisiologia , Adulto , Estradiol/sangue , Estrona/sangue , Feminino , Fase Folicular/fisiologia , Força da Mão/fisiologia , Humanos , Concentração de Íons de Hidrogênio , Isquemia/fisiopatologia , Espectroscopia de Ressonância Magnética , Menstruação/fisiologia , Contração Muscular/fisiologia , Músculo Esquelético/inervação , Músculo Esquelético/fisiologia , Ácidos Fosfóricos/metabolismo , Reflexo/fisiologiaRESUMO
In summary, we studied 4 patients with mixed-type CS hypersensitivity. We demonstrated that CS massage rapidly inhibits sympathetic nerve activity and decreases heart rate. Arterial pressure starts to decline abruptly with complete sympathetic withdrawal, but the nadir is delayed, suggesting that arterial dilation is not instantaneous. Arterial pressure rebounds slowly, suggesting a latency between the neural reflex and vascular compliance. Pacing had little effect on preventing hypotension in these patients. Our data support the concept that sympathetic withdrawal is responsible for the vasodilatory component seen with CS syncope.
Assuntos
Pressão Sanguínea/fisiologia , Seio Carotídeo/fisiopatologia , Pressorreceptores/fisiopatologia , Sistema Nervoso Simpático/fisiopatologia , Síncope/fisiopatologia , Idoso , Idoso de 80 Anos ou mais , Estimulação Cardíaca Artificial/métodos , Frequência Cardíaca/fisiologia , Humanos , Masculino , Pessoa de Meia-Idade , Músculo Esquelético/inervação , Marca-Passo Artificial , Síncope/etiologia , SíndromeRESUMO
We compared reflex responses to static handgrip at 30% maximal voluntary contraction (MVC) in 26 untrained men (mean age 35 +/- 3 yr) and 23 untrained women (mean age 39 +/- 4 yr). Women demonstrated attenuated increases in blood pressure and muscle sympathetic nerve activity (MSNA; by microneurography) compared with men. This difference was also observed during a period of posthandgrip circulatory arrest. 31P-nuclear magnetic resonance (NMR) spectroscopy studies demonstrated attenuations in the production of diprotonated phosphate and the development of cellular acidosis in women compared with men. Subjects also performed ischemic handgrip to fatigue. During this paradigm, MSNA responses were similar in the two groups, suggesting that freely perfused conditions are necessary for the full expression of the gender effect. Finally, we examined MSNA responses to adductor pollicus exercise in 7 men (26 +/- 1 yr) and 6 women (25 +/- 2 yr). MVC values and times to fatigue were similar in the two groups (MVC: men, 4.3 +/- 0.4 kg; women, 4.0 +/- 0.3 kg; not significant. Time to fatigue: men, 209 +/- 16 s; women, 287 +/- 50 s; not significant). At periods of end exercise and postexercise circulatory arrest, MSNA responses were attenuated in the women compared with the men. We conclude that, during nonischemic static exercise, sympathetic neural outflow is less in women compared with men. This response is due to an attenuated metaboreflex in women. Finally, on the basis of the adductor pollicus experiments, this effect appears independent of muscle mass, workload, and the level of training.
Assuntos
Exercício Físico/fisiologia , Sistema Nervoso Simpático/fisiologia , Acidose/metabolismo , Adulto , Envelhecimento/fisiologia , Feminino , Mãos/fisiologia , Hemodinâmica/fisiologia , Humanos , Espectroscopia de Ressonância Magnética , Masculino , Contração Muscular/fisiologia , Fadiga Muscular/fisiologia , Músculo Esquelético/anatomia & histologia , Músculo Esquelético/inervação , Músculo Esquelético/fisiologia , Consumo de Oxigênio/fisiologia , Caracteres SexuaisRESUMO
Directional coronary atherectomy (DCA) has been shown to be a safe and effective treatment for occlusive coronary artery disease. We report a case of an atherectomy guiding catheter severing in two with successful retrieval of the dislodged segment by an integrated angioplasty balloon catheter system.
Assuntos
Angioplastia Coronária com Balão/instrumentação , Aterectomia Coronária/instrumentação , Vasos Coronários , Corpos Estranhos/terapia , Idoso , Angioplastia Coronária com Balão/métodos , Aterectomia Coronária/efeitos adversos , Doença da Artéria Coronariana/terapia , Falha de Equipamento , Feminino , Corpos Estranhos/etiologia , HumanosRESUMO
Post leg exercise circulatory arrest (PLE-CA) raises blood pressure (BP) and reduces peak forearm vascular conductance (C). This reflex is evoked by activation of muscle afferents that are often sensitive to lactic acid. We tested the hypothesis that lactic acid reductions induced by muscle glycogen depletion would attenuate the lower-limb metaboreceptor-mediated pressor and forearm vasoconstrictor responses. Eleven subjects had C measured (plethysmography) during post leg exercise circulatory arrest (PLE-CA) (supine bicycle exercise for 9 min, 10 s at 75% VO2max before and after undergoing a glycogen-depletion paradigm (24-h fast followed by 10 min of supine leg exercise at 75% VO2max). In six subjects with lower lactate values, C during PLE-CA was higher after glycogen depletion (0.39 +/- 0.05 vs. 0.21 +/- 0.01 ml.min-1.100 ml-1 x mmHg-1; P < 0.01) and BP was lower (113 +/- 6 vs. 128 +/- 6 mmHg, P < 0.01). In five subjects without attenuated lactate responses, C and BP during PLE-CA were not different. Muscle biopsies (n = 5) demonstrated that the paradigm lowered muscle glycogen concentrations. Thus glycogen depletion-induced reductions in muscle lactate are associated with reduced muscle metaboreceptor-mediated responses.
Assuntos
Glicogênio/deficiência , Lactatos/metabolismo , Esforço Físico , Reflexo/fisiologia , Adulto , Biópsia , Pressão Sanguínea , Antebraço/irrigação sanguínea , Frequência Cardíaca , Humanos , Hiperemia/fisiopatologia , Ácido Láctico , Músculos/patologia , Fluxo Sanguíneo Regional , Reprodutibilidade dos Testes , Pele/irrigação sanguíneaRESUMO
BACKGROUND: Resting sympathetic nervous system activity is increased in heart failure. Whether sympathetic nervous system responses during exercise are increased is controversial. Furthermore, the role of muscle metaboreceptors and central command in regulating sympathetic outflow has been largely unexplored. METHODS AND RESULTS: Muscle sympathetic nerve activity (MSNA, peroneal nerve) was measured in nine heart failure subjects and eight age-matched control subjects during static exercise (30% maximal voluntary contraction) for 2 minutes and during a period of posthandgrip regional circulatory arrest. This maneuver isolates the metaboreceptor contribution to sympathetic nervous system responses. MSNA responses were similar during static exercise in the two groups. During posthandgrip regional circulatory arrest we observed a marked attenuation in MSNA responses in the heart failure subjects (15% increase in heart failure versus 57% increase in control subjects). A cold pressor test demonstrated a normal MSNA response to a potent nonspecific stimulus in the heart failure subjects (heart failure subjects, 141% increase; control subjects, 215% increase; NS). Nuclear magnetic resonance spectroscopy studies in five separate heart failure subjects and five control subjects suggested that the attenuated metaboreceptor response in heart failure was not due to reduced H+ production. CONCLUSIONS: Skeletal muscle metaboreceptor responses are impaired in heart failure. Because MSNA responses during static exercise are similar in the two groups, mechanisms aside from metaboreceptor stimulation must be important in increasing sympathetic nervous system activity.