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Evidence that the degree of obstructive sleep apnea may not increase myocardial ischemia and arrhythmias in patients with stable coronary artery disease

ARAÚJO, Cristiana Marques de; SOLIMENE, Maria Cecilia; GRUPI, Cesar Jose; GENTA, Pedro Rodrigues; LORENZI-FILHO, Geraldo; LUZ, Protásio Lemos Da
Fonte: Faculdade de Medicina / USP Publicador: Faculdade de Medicina / USP
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
68.229004%
There is controversy regarding whether obstructive sleep apnea is responsible for triggering myocardial ischemia, arrhythmias and heart rate variability in patients with coronary artery disease. OBJETIVE: The objective of this study was to identify relationships between sleep apnea, myocardial ischemia and cardiac arrhythmia in patients with coronary artery disease. METHODS: Fifty-three patients with stable coronary disease underwent simultaneous polysomnography and electrocardiographic Holter recording. The apnea-hypopnea index (AHI) was defined as the number of apneas/hypopneas per hour of sleep. Patients were divided into a Control group (AHI15, n=23 pts) and an Apnea group (AHI>15, n=30 pts). A subgroup of 13 patients with an AHI>30 (Severe Apnea group) was also studied. We analyzed ischemic episodes (ST-segment depressions >1 mm, > 1 min), heart rate variability and the occurrence of arrhythmias during wakefulness and sleep. RESULTS: Baseline clinical characteristics among the groups were similar except for higher blood pressure in the Apnea groups (p<0.05). Myocardial ischemia was recorded in 39 (73.6%) patients. The number and duration of ischemic episodes significantly decreased during sleep in all groups; during wakefulness...

Improved Endothelial Function and Reversal of Myocardial Perfusion Defects after Aerobic Physical Training in a Patient with Microvascular Myocardial Ischemia

CARVALHO, Eduardo Elias Vieira; CRESCENCIO, Julio Cesar; ELIAS JR., Jorge; BRITO, Laura Beatriz Alves; GALLO JR., Lourenco; SIMOES, Marcus Vinicius
Fonte: LIPPINCOTT WILLIAMS & WILKINS Publicador: LIPPINCOTT WILLIAMS & WILKINS
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
68.16409%
The objective of this report is to document the effects of an aerobic training program on myocardial perfusion, and endothelial function abnormalities, and on the relief of angina in a patient with microvascular myocardial ischemia. A 53-year-old female patient exhibited precordial pain on effort and angiographically normal coronaries. Her symptoms had been present for 4 yrs despite pharmacologic treatment for the control of risk factors, with myocardial perfusion scintigraphy revealing an extensive reversible perfusion defect. She was submitted to aerobic training for 4 mos, obtaining significant improvement of the anginal symptoms. Additionally, after the aerobic training program, scintigraphy revealed the disappearance of the myocardial perfusion defect, with a marked improvement of endothelium-dependent vasodilatory response and an improved quality-of-life score. These results suggest that aerobic training can improve endothelial function, leading to a reduction of ischemia and an improved quality-of-life in patients with microvascular myocardial ischemia.; FAPESP[08/04140-3]

Relação entre apnéia do sono, isquemia miocárdica, variabilidade da freqüência cardíaca e arritmias em portadores de doença arterial coronária; Relation between sleep apnea, myocardial ischemia, heart rate variability and arrhythmias in patients with coronary artery disease

Araújo, Cristiana Marques de
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 02/05/2007 Português
Relevância na Pesquisa
68.05044%
Introdução: É comum a associação entre apnéia do sono e a doença arterial coronária (DAC), devido a fatores predisponentes comuns como sexo masculino e obesidade. Entretanto, ainda não existe uma definição objetiva da relação entre apnéia e DAC. Objetivo: Avaliar se os episódios de isquemia miocárdica, a variabilidade da freqüência cardíaca (VFC) e as arritmias cardíacas de portadores de DAC sofrem alteração na presença da apnéia do sono. Métodos: Cinqüenta e três pacientes portadores de DAC foram submetidos à monitorização eletrocardiográfica ambulatorial de 48 horas e ao estudo do sono na primeira noite da monitorização. Os pacientes foram divididos de acordo com o índice de apnéia e hipopnéia (IAH) em: grupo Controle (IAH<=15) e grupo Apnéia (IAH>15). Os grupos foram comparados quanto à isquemia miocárdica, VFC e arritmias cardíacas ocorridas no período da vigília e do sono. Uma subanálise apenas com pacientes portadores de apnéia grave (IAH>30 - grupo Ap-Grave) foi realizada e comparada ao grupo Controle. A análise estatística foi realizada utilizando-se o teste de Mann-Whitney, teste de Fisher e teste T de student. Resultados: Não foram observadas diferenças nas características clínicas básicas entre os grupos...

Efeitos do treinamento físico contínuo ou intervalado em um modelo experimental de dislipidemia e isquemia miocárdica; Effects of continuous or interval physical training on an experimental model of dyslipidemia and myocardial ischemia

Abad, César Cavinato Cal
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 04/06/2013 Português
Relevância na Pesquisa
67.916196%
O infarto do miocárdio (IM) é a doença cardiovascular que mais causa morte e invalidez em todo o mundo. O uso de animais experimentais tem auxiliado a compreender melhor a fisiopatologia e as formas de tratamento do IM. Sabendo que as dislipidemias estão associadas com o IM e que o treinamento físico pode ser prescrito para prevenção e tratamento de doenças cardiovasculares, no presente trabalho, investigamos os efeitos de dois tipos de treinamentos físicos em um modelo experimental de dislipidemia e isquemia miocárdica. Camundongos selvagens (WT) e knockout para o receptor LDL (LDL-/-) foram divididos em oito grupos: a) LDLr-/- sedentário (LDL-S); b) LDLr-/- infartado sedentário (LDL-IM-S); c) LDLr-/- infartado submetido a treinamento contínuo (LDL-IM-C); d) LDLr-/- infartado submetido a treinamento intervalado (LDL-IM-I); e) WT sedentário (WT-S); f) WT infartado sedentário (WT-IM-S); g) WT infartado submetido a treinamento contínuo (WT-IM-C); h) WT infartado submetido a treinamento intervalado (WT-IM-I). Após 60 dias da ligadura da artéria coronária descendente, o treino contínuo constou de corrida a 60% do máximo e o intervalado de 8 tiros de 4min a 80% do máximo e recuperação de 4min a 40% do máximo. Nos animais WT infartados...

Estudo comparativo da identificacao de isquemia miocardica pela cineventriculografia contrastada sob o efeito de mononitrato de isossorbitol e pela cintilografia miocardica perfusional em portadores de cardiopatia isquemica; Comparative study for the identification of myocardial ischemia by contrast ventriculography under the effect of isosorbide mononitrate and by perfusional myocardial scintigraphy in patients with ischemic heart disease

Ludwig, Roberto Telles de Freitas; Kirschnick, Luciana Schmidt; Souza, Josiane de; Ribeiro, Leticia Weiss; Ordovas, Karen Gomes; Leitão, Cristiane Bauermann; Cruz, Rosana; Candiago, Rafael Henriques
Fonte: Universidade Federal do Rio Grande do Sul Publicador: Universidade Federal do Rio Grande do Sul
Tipo: Artigo de Revista Científica Formato: application/pdf
Português
Relevância na Pesquisa
68.09033%
Objective – To evaluate and compare the usefulness of cineventriculographies, before and after nitrate use, to technetium-99m sestamibi scintigraphy for the identification of myocardial ischemia. Methods – Twenty-six patients were studied at basal conditions and 5 minutes after intravenous administration of isosorbide mononitrate (0.3mg/kg), to evaluate the performance and regional wall motion of the left ventricle (LV). The results were compared to those obtained with technetium- 99m sestamibi scintigraphy. Results – Before nitrate, contrast ventriculography identified 30 normal segments, 62 hypokinetic segments, 28 dyskinetic segments, and 14 akinetic segments. After drug administration, 99 segments were normal, 11 hypokinetic, 11 dyskinetic, and 13 akinetic. Myocardial scintigraphy revealed 110 ischemic segments and 18 fibrotic segments (p<0.005). After drug administration, the ventriculography showed increase in the velocity of circumferential fiber shortening (p=0.0142), the ejection fraction (p=0.0462), decrease in the end-systolic volume (p=0.0031) and no change in end-diastolic volume. Conclusion – Contrast ventriculography using nitrate proved to be similar to perfusional myocardial scintigraphy in the identification of myocardial ischemia.

Fatores associados à isquemia miocárdica na hipertensão arterial resistente; Predictors of myocardial ischemia in resistant hypertension

Rodrigo Gimenez Pissutti Modolo
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 06/06/2014 Português
Relevância na Pesquisa
68.42526%
INTRODUÇÃO: A hipertensão arterial é o mais prevalente e significante fator de risco modificável para doença arterial coronariana (DAC). Uma parte destes pacientes com hipertensão descontrolada é classificada como sendo portadora da Hipertensão Arterial Resistente (HAR). A incidência da isquemia miocárdica e da DAC aumenta juntamente com a ascensão dos níveis pressóricos. No entanto, a prevalência de isquemia miocárdica em pacientes com HAR é desconhecida, bem como os fatores associados à primeira. MÉTODOS: Analisamos 129 pacientes com HAR verdadeira, seguidos regularmente em nosso ambulatório especializado. Foram realizados cintilografia de perfusão miocárdica em repouso e após stress farmacológico por dipiridamol nestes indivíduos. Os pacientes eram então divididos em dois grupos: com (I-HAR, n=36) e sem (SI-HAR, n=93) isquemia miocárdica. Ecocardiograma, MAPA-24h (para inclusive análise de efeito do jaleco branco), e vasodilatação mediada por fluxo (VMF) também foram realizados. RESULTADOS: Trinta e seis pacientes (28%) tinham isquemia miocárdica e 49% apresentavam o efeito do jaleco branco (EJB). O EJB esteve associado com alta prevalência de isquemia miocárdica (49,2% vs. 7,6%, p<0,001). Não houve diferença entre os grupos no que concerne à idade...

Silent myocardial ischemia screening in patients with diabetes mellitus

Barthelemy,Olivier; Le Feuvre,Claude; Timsit,José
Fonte: Sociedade Brasileira de Endocrinologia e Metabologia Publicador: Sociedade Brasileira de Endocrinologia e Metabologia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/03/2007 Português
Relevância na Pesquisa
67.80076%
The prevalence of diabetes mellitus is fairly increasing, especially in the developing countries. Diabetes is a major cardiovascular risk factor; it often leads to severe cardiovascular complications, and coronary artery disease (CAD) is the main cause of death in diabetic patients. Silent myocardial ischemia (SMI) is more frequent in diabetic patients. The progress made in detection and treatment of CAD allows reconsidering the screening of SMI, in the hope that early CAD diagnosis leads to a more effective therapy and the decrease of cardiovascular complications and mortality. However, the benefit of systematic SMI screening remains discussed. Current guidelines recommend screening SMI in asymptomatic diabetic patients selected for high cardiovascular risk (i.e. with two or more other cardiovascular risk factors, or peripheral or carotid arterial disease, or proteinuria). ECG stress test can be recommended in first intention if maximal heart rate can be achieved. For patient with inconclusive ECG stress test, myocardial scintigraphy seems more accurate than stress echocardiography. Coronary angiogram should be performed in case of positive stress test. Further evaluations of systematic screening have to be conducted on broad randomized trial.

Comparative study for the identification of myocardial ischemia by contrast ventriculography under the effect of isosorbide mononitrate and by perfusional myocardial scintigraphy in patients with ischemic heart disease

Manfroi,Waldomiro Carlos; Ludwig,Roberto; Kirschnick,Luciana Schmidt; Souza,Josiane; Ribeiro,Letícia Weiss; Ordovás,Karen; Leitão,Cristiane; Cruz,Rosana; Candiago,Rafael
Fonte: Sociedade Brasileira de Cardiologia - SBC Publicador: Sociedade Brasileira de Cardiologia - SBC
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/02/1999 Português
Relevância na Pesquisa
68.09033%
OBJECTIVE: To evaluate and compare the usefulness of cineventriculographies, before and after nitrate use, to technetium-99m sestamibi scintigraphy for the identification of myocardial ischemia. METHODS: Twenty-six patients were studied at basal conditions and 5 minutes after intravenous administration of isosorbide mononitrate (0.3mg/kg), to evaluate the performance and regional wall motion of the left ventricle (LV). The results were compared to those obtained with technetium-99m sestamibi scintigraphy. RESULTS: Before nitrate, contrast ventriculography identified 30 normal segments, 62 hypokinetic segments, 28 dyskinetic segments, and 14 akinetic segments. After drug administration, 99 segments were normal, 11 hypokinetic, 11 dyskinetic, and 13 akinetic. Myocardial scintigraphy revealed 110 ischemic segments and 18 fibrotic segments (p<0.005). After drug administration, the ventriculography showed increase in the velocity of circumferential fiber shortening (p=0.0142), the ejection fraction (p=0.0462), decrease in the end-systolic volume (p=0.0031) and no change in end-diastolic volume. CONCLUSION: Contrast ventriculography using nitrate proved to be similar to perfusional myocardial scintigraphy in the identification of myocardial ischemia.

Does a circadian variation occur in myocardial ischemia over 48 hours in patients with unstable angina?

César,Luiz Antônio Machado; Ferreira,João Fernando Monteiro; Grupi,César J.; Pamplona,David; Moretti,Miguel A.; Pferfmann,Elcio; Ramires,José A. F.
Fonte: Sociedade Brasileira de Cardiologia - SBC Publicador: Sociedade Brasileira de Cardiologia - SBC
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/07/2000 Português
Relevância na Pesquisa
68.076963%
OBJECTIVE: To study the incidence of and variation in myocardial ischemia over 48 hours in patients with unstable angina. METHODS: Thirty-nine patients with unstable angina underwent long-term electrocardiography for 48 hours. The number of events and the period of time of ischemia (in minutes) were analyzed for the 48 hours, in two periods of 24 hours, and in periods of 4 hours. RESULTS: We analyzed 1755.8 hours of monitoring tapes, and ischemic episodes were detected in 18 (46.2%) patients, corresponding to 173 ischemic episodes, allowing the evaluation of 1304 minutes of ischemia.only 4 of which were (2.2%) symptomatic, Considering the entire period of time of recording and the predetermined time intervals, we observed a higher number of ischemic episodes (38) and a longer duration of ischemia (315.4 minutes) between 11:00 am and 3:00 pm. However, no significant differences occurred among the values in the different intervals. CONCLUSION: Long-term electrocardiography over 48 hours showed a high incidence (97.8%) of silent ischemic episodes in patients with unstable angina. No evidence of a circadian variation of myocardial ischemia in unstable angina was observed.

Physical Stress Echocardiography: Prediction of Mortality and Cardiac Events in Patients with Exercise Test showing Ischemia

Araujo,Ana Carla Pereira de; Santos,Bruno F. de Oliveira; Calasans,Flavia Ricci; Pinto,Ibraim M. Francisco; Oliveira,Daniel Pio de; Melo,Luiza Dantas; Andrade,Stephanie Macedo; Tavares,Irlaneide da Silva; Sousa,Antonio Carlos Sobral; Oliveira,Joselina Luz
Fonte: Sociedade Brasileira de Cardiologia - SBC Publicador: Sociedade Brasileira de Cardiologia - SBC
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/11/2014 Português
Relevância na Pesquisa
58.257646%
Background: Studies have demonstrated the diagnostic accuracy and prognostic value of physical stress echocardiography in coronary artery disease. However, the prediction of mortality and major cardiac events in patients with exercise test positive for myocardial ischemia is limited. Objective: To evaluate the effectiveness of physical stress echocardiography in the prediction of mortality and major cardiac events in patients with exercise test positive for myocardial ischemia. Methods: This is a retrospective cohort in which 866 consecutive patients with exercise test positive for myocardial ischemia, and who underwent physical stress echocardiography were studied. Patients were divided into two groups: with physical stress echocardiography negative (G1) or positive (G2) for myocardial ischemia. The endpoints analyzed were all-cause mortality and major cardiac events, defined as cardiac death and non-fatal acute myocardial infarction. Results: G2 comprised 205 patients (23.7%). During the mean 85.6 ± 15.0-month follow-up, there were 26 deaths, of which six were cardiac deaths, and 25 non-fatal myocardial infarction cases. The independent predictors of mortality were: age, diabetes mellitus, and positive physical stress echocardiography (hazard ratio: 2.69; 95% confidence interval: 1.20 - 6.01; p = 0.016). The independent predictors of major cardiac events were: age...

Assessment of Myocardial Ischemia in Obese Individuals Undergoing Physical Stress Echocardiography (PSE)

Silveira,Mara Graziele Maciel; Sousa,Antônio Carlos Sobral; Santos,Marcos Antônio Almeida; Tavares,Irlaneide da Silva; Andrade,Stephanie Macedo; Melo,Luiza Dantas; Andrade,Loren Suyane Oliveira de; Santos,Emmanuel Lima Almeida; Oliveira,Joselina Luzia M
Fonte: Sociedade Brasileira de Cardiologia - SBC Publicador: Sociedade Brasileira de Cardiologia - SBC
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2015 Português
Relevância na Pesquisa
68.10371%
Background: Physical stress echocardiography is an established methodology for diagnosis and risk stratification of coronary artery disease in patients with physical capacity. In obese (body mass index ≥ 30 kg/m2) the usefulness of pharmacological stress echocardiography has been demonstrated; however, has not been reported the use of physical stress echocardiography in this growing population group. Objective: To assess the frequency of myocardial ischemia in obese and non-obese patients undergoing physical stress echocardiography and compare their clinical and echocardiographic differences. Methods: 4,050 patients who underwent treadmill physical stress echocardiography were studied according to the Bruce protocol, divided into two groups: obese (n = 945; 23.3%) and non-obese (n = 3,105; 76.6%). Results: There was no difference regarding gender. Obese patients were younger (55.4 ± 10.9 vs. 57.56 ± 11.67) and had a higher frequency of hypertension (75.2% vs. 57, 2%; p < 0.0001), diabetis mellitus (15.2% vs. 10.9%; p < 0.0001), dyslipidemia (59.5% vs 51.9%; p < 0.0001), family history of coronary artery disease (59.3% vs. 55.1%; p = 0.023) and physical inactivity (71.4% vs. 52.9%, p < 0.0001). The obese had greater aortic dimensions (3.27 vs. 3.14 cm; p < 0.0001)...

Exercise may cause myocardial ischemia at the anaerobic threshold in cardiac rehabilitation programs

Fuchs,A.R.C.N.; Meneghelo,R.S.; Stefanini,E.; De Paola,A.V.; Smanio,P.E.P.; Mastrocolla,L.E.; Ferraz,A.S.; Buglia,S.; Piegas,L.S.; Carvalho,A.A.C.
Fonte: Associação Brasileira de Divulgação Científica Publicador: Associação Brasileira de Divulgação Científica
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/03/2009 Português
Relevância na Pesquisa
68.28917%
Myocardial ischemia may occur during an exercise session in cardiac rehabilitation programs. However, it has not been established whether it is elicited when exercise prescription is based on heart rate corresponding to the anaerobic threshold as measured by cardiopulmonary exercise testing. Our objective was to determine the incidence of myocardial ischemia in cardiac rehabilitation programs according to myocardial perfusion SPECT in exercise programs based on the anaerobic threshold. Thirty-nine patients (35 men and 4 women) diagnosed with coronary artery disease by coronary angiography and stress technetium-99m-sestamibi gated SPECT associated with a baseline cardiopulmonary exercise test were assessed. Ages ranged from 45 to 75 years. A second cardiopulmonary exercise test determined training intensity at the anaerobic threshold. Repeat gated-SPECT was obtained after a third cardiopulmonary exercise test at the prescribed workload and heart rate. Myocardial perfusion images were analyzed using a score system of 6.4 at rest, 13.9 at peak stress, and 10.7 during the prescribed exercise (P < 0.05). The presence of myocardial ischemia during exercise was defined as a difference ≥2 between the summed stress score and summed rest score. Accordingly...

CPU0213, a novel endothelin type A and type B receptor antagonist, protects against myocardial ischemia/reperfusion injury in rats

Wang,Z.Y.; Zhang,W.; Li,X.Z.; Han,Y.; Chen,Y.P.; Liu,Z.; Xie,L.P.; Ji,Y.; Lu,X.
Fonte: Associação Brasileira de Divulgação Científica Publicador: Associação Brasileira de Divulgação Científica
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/11/2011 Português
Relevância na Pesquisa
67.981445%
The efficacy of endothelin receptor antagonists in protecting against myocardial ischemia/reperfusion (I/R) injury is controversial, and the mechanisms remain unclear. The aim of this study was to investigate the effects of CPU0123, a novel endothelin type A and type B receptor antagonist, on myocardial I/R injury and to explore the mechanisms involved. Male Sprague-Dawley rats weighing 200-250 g were randomized to three groups (6-7 per group): group 1, Sham; group 2, I/R + vehicle. Rats were subjected to in vivo myocardial I/R injury by ligation of the left anterior descending coronary artery and 0.5% sodium carboxymethyl cellulose (1 mL/kg) was injected intraperitoneally immediately prior to coronary occlusion. Group 3, I/R + CPU0213. Rats were subjected to identical surgical procedures and CPU0213 (30 mg/kg) was injected intraperitoneally immediately prior to coronary occlusion. Infarct size, cardiac function and biochemical changes were measured. CPU0213 pretreatment reduced infarct size as a percentage of the ischemic area by 44.5% (I/R + vehicle: 61.3 ± 3.2 vs I/R + CPU0213: 34.0 ± 5.5%, P < 0.05) and improved ejection fraction by 17.2% (I/R + vehicle: 58.4 ± 2.8 vs I/R + CPU0213: 68.5 ± 2.2%, P < 0.05) compared to vehicle-treated animals. This protection was associated with inhibition of myocardial inflammation and oxidative stress. Moreover...

Evidence that the degree of obstructive sleep apnea may not increase myocardial ischemia and arrhythmias in patients with stable coronary artery disease

Araújo,Cristiana Marques de; Solimene,Maria Cecilia; Grupi,Cesar Jose; Genta,Pedro Rodrigues; Lorenzi-Filho,Geraldo; Luz,Protásio Lemos Da
Fonte: Faculdade de Medicina / USP Publicador: Faculdade de Medicina / USP
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/03/2009 Português
Relevância na Pesquisa
68.229004%
There is controversy regarding whether obstructive sleep apnea is responsible for triggering myocardial ischemia, arrhythmias and heart rate variability in patients with coronary artery disease. OBJETIVE: The objective of this study was to identify relationships between sleep apnea, myocardial ischemia and cardiac arrhythmia in patients with coronary artery disease. METHODS: Fifty-three patients with stable coronary disease underwent simultaneous polysomnography and electrocardiographic Holter recording. The apnea-hypopnea index (AHI) was defined as the number of apneas/hypopneas per hour of sleep. Patients were divided into a Control group (AHI15, n=23 pts) and an Apnea group (AHI>15, n=30 pts). A subgroup of 13 patients with an AHI>30 (Severe Apnea group) was also studied. We analyzed ischemic episodes (ST-segment depressions >1 mm, > 1 min), heart rate variability and the occurrence of arrhythmias during wakefulness and sleep. RESULTS: Baseline clinical characteristics among the groups were similar except for higher blood pressure in the Apnea groups (p<0.05). Myocardial ischemia was recorded in 39 (73.6%) patients. The number and duration of ischemic episodes significantly decreased during sleep in all groups; during wakefulness...

Concentrated Ambient Particles Alter Myocardial Blood Flow During Acute Ischemia in Conscious Canines

Bartoli, Carlo R.; Wellenius, Gregory A.; Akiyama, Ichiro; Okabe, Kazunori; Coull, Brent Andrew; Diaz, Edgar; Lawrence, Joy E.; Verrier, Richard Leonard; Godleski, John Joseph
Fonte: National Institute of Environmental Health Sciences Publicador: National Institute of Environmental Health Sciences
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
58.2468%
Background: Experimental and observational studies have demonstrated that short-term exposure to ambient particulate matter (PM) exacerbates myocardial ischemia. Objectives: We conducted this study to investigate the effects of concentrated ambient particles (CAPs) on myocardial blood flow during myocardial ischemia in chronically instrumented conscious canines. Methods: Eleven canines were instrumented with a balloon occluder around the left anterior descending coronary artery and catheters for determination of myocardial blood flow using fluorescent microspheres. Telemetric electrocardiographic and blood pressure monitoring was available for four of these animals. After recovery, we exposed animals by inhalation to 5 hr of either filtered air or CAPs (mean concentration ± SD, 349.0 ± 282.6 μg/m(^{3})) in a crossover protocol. We determined myocardial blood flow during a 5-min coronary artery occlusion immediately after each exposure. Data were analyzed using mixed models for repeated measures. The primary analysis was based on four canines that completed the protocol. Results: CAPs exposure decreased total myocardial blood flow during coronary artery occlusion by 0.12 mL/min/g (p < 0.001) and was accompanied by a 13% (p < 0.001) increase in coronary vascular resistance. Rate–pressure product...

Potential utility of changes in entropy as an adjunct to the electrocardiography diagnosis of reversible myocardial ischaemia.

Zhao, Jinlin
Fonte: Universidade de Adelaide Publicador: Universidade de Adelaide
Tipo: Tese de Doutorado
Publicado em //2008 Português
Relevância na Pesquisa
58.494976%
Background: The 12-lead electrocardiogram (ECG) is a pivotal clinical investigation for evaluations of disorders of myocardial electrophysiology and function. Myocardial ischemia is generally diagnosed on the basis of clinical history, combined with ST segment shifts and T wave changes on resting 12-lead ECG. The ECG is also used as a monitoring tool for assessment of resolution of transmural ischemia following emergency treatment. Because this technology is easy, noninvasive, and inexpensive, it represents a convenient central investigative modality. On the other hand, the 12-lead ECG exhibits very low predictive accuracy for the diagnosis of ischemia in the absence of concurrent symptoms. Even if ECG monitoring is combined with treadmill exercise, the sensitivity and positive predictive accuracy for detection of myocardial ischemia are only around 50% - 75%. Therefore, information from the ECG, combined with exercise test, does not usually have a large influence on clinical decision-making. A number of imaging techniques may be combined with pacing-induced tachycardia or pharmacological stress in order to improve the diagnostic accuracy of such provocative tests for ischemia beyond the level provided by continuous ECG monitoring alone. These include echocardiography...

Assessment of Myocardial Ischemia in Obese Individuals Undergoing Physical Stress Echocardiography (PSE)

Silveira,Mara Graziele Maciel; Sousa,Antônio Carlos Sobral; Santos,Marcos Antônio Almeida; Tavares,Irlaneide da Silva; Andrade,Stephanie Macedo; Melo,Luiza Dantas; Andrade,Loren Suyane Oliveira de; Santos,Emmanuel Lima Almeida; Oliveira,Joselina Luzia M
Fonte: Sociedade Brasileira de Cardiologia - SBC Publicador: Sociedade Brasileira de Cardiologia - SBC
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/05/2015 Português
Relevância na Pesquisa
68.10371%
Background: Physical stress echocardiography is an established methodology for diagnosis and risk stratification of coronary artery disease in patients with physical capacity. In obese (body mass index ≥ 30 kg/m2) the usefulness of pharmacological stress echocardiography has been demonstrated; however, has not been reported the use of physical stress echocardiography in this growing population group. Objective: To assess the frequency of myocardial ischemia in obese and non-obese patients undergoing physical stress echocardiography and compare their clinical and echocardiographic differences. Methods: 4,050 patients who underwent treadmill physical stress echocardiography were studied according to the Bruce protocol, divided into two groups: obese (n = 945; 23.3%) and non-obese (n = 3,105; 76.6%). Results: There was no difference regarding gender. Obese patients were younger (55.4 ± 10.9 vs. 57.56 ± 11.67) and had a higher frequency of hypertension (75.2% vs. 57, 2%; p < 0.0001), diabetis mellitus (15.2% vs. 10.9%; p < 0.0001), dyslipidemia (59.5% vs 51.9%; p < 0.0001), family history of coronary artery disease (59.3% vs. 55.1%; p = 0.023) and physical inactivity (71.4% vs. 52.9%, p < 0.0001). The obese had greater aortic dimensions (3.27 vs. 3.14 cm; p < 0.0001)...

Short-term myocardial ischemia induces cardiac modified C-reactive protein expression and proinflammatory gene (cyclo-oxygenase-2, monocyte chemoattractant protein-1, and tissue factor) upregulation in peripheral blood mononuclear cells

Vilahur, Gemma; Hernández-Vera, Rodrigo; Molins, Blanca; Casaní, Laura; Duran, Xavier; Padró, Teresa; Badimón, Lina
Fonte: Blackwell Publishing Publicador: Blackwell Publishing
Tipo: Artículo Formato: 918459 bytes; application/pdf
Português
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9 pages.-- PMID: 19036073 [PubMed].; [Background] Prompt coronary thrombus resolution, reducing time of ischemia, improves cardiac recovery. The factors triggered by ischemia that contribute to the clinical outcome are not fully known. We hypothesize that unabated inflammation due to cardiac ischemia may be a contributing factor.; [Aims] As a proof-of-concept, we evaluated the effect of short-term myocardial ischemia on the local and systemic inflammatory response.; [Methods] Pigs underwent either 90-min mid-left anterior descending (LAD) coronary artery balloon occlusion (infarct size 25% ± 1% left ventricle; 29% heart function deterioration) or a sham-operation procedure. Peri-infarcted and non-ischemic cardiac tissue was obtained for histopathologic, molecular and immunohistochemical analysis of inflammatory markers [interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), modified C-reactive protein (mCRP), and human alveolar macrophage-56 (HAM-56)]. Blood (femoral vein) was withdrawn prior to myocardial infarction (MI) induction (t = 0) and at 30 and 90 min to evaluate: (i) systemic cytokine levels (IL-6, TNF-α, CRP); (ii) proinflammatory gene and protein expression in peripheral blood mononuclear cells (PBMCs) of tissue factor (TF)...

Evidence that the degree of obstructive sleep apnea may not increase myocardial ischemia and arrhythmias in patients with stable coronary artery disease

Araújo, Cristiana Marques de; Solimene, Maria Cecilia; Grupi, Cesar Jose; Genta, Pedro Rodrigues; Lorenzi-Filho, Geraldo; Luz, Protásio Lemos Da
Fonte: Universidade de São Paulo. Faculdade de Medicina Publicador: Universidade de São Paulo. Faculdade de Medicina
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; ; ; ; ; ; Formato: application/pdf
Publicado em 01/03/2009 Português
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There is controversy regarding whether obstructive sleep apnea is responsible for triggering myocardial ischemia, arrhythmias and heart rate variability in patients with coronary artery disease. OBJETIVE: The objective of this study was to identify relationships between sleep apnea, myocardial ischemia and cardiac arrhythmia in patients with coronary artery disease. METHODS: Fifty-three patients with stable coronary disease underwent simultaneous polysomnography and electrocardiographic Holter recording. The apnea-hypopnea index (AHI) was defined as the number of apneas/hypopneas per hour of sleep. Patients were divided into a Control group (AHI15, n=23 pts) and an Apnea group (AHI>;15, n=30 pts). A subgroup of 13 patients with an AHI>;30 (Severe Apnea group) was also studied. We analyzed ischemic episodes (ST-segment depressions >;1 mm, >; 1 min), heart rate variability and the occurrence of arrhythmias during wakefulness and sleep. RESULTS: Baseline clinical characteristics among the groups were similar except for higher blood pressure in the Apnea groups (p

Lipid levels as predictors of silent myocardial ischemia in a type 2 diabetic population in Havana

Peña,Yamilé; Fernández-Britto,José E.; Bacallao,Jorge; Batista,Juan F.; León,María L. de
Fonte: Medical Education Cooperation with Cuba Publicador: Medical Education Cooperation with Cuba
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2012 Português
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INTRODUCTION Silent myocardial ischemia is frequent in type 2 diabetics, therefore, symptoms cannot be relied upon for diagnosis and followup in these patients. Various studies relate blood lipid levels to cardiovascular diseases, and several authors describe certain lipoproteins as independent predictors of ischemia. OBJECTIVE Identify blood lipid levels that predict silent myocardial ischemia in a type 2 diabetic population in Havana. METHODS From May 2005 through May 2009, assessment was done of 220 asymptomatic type 2 diabetics in ten polyclinics in Havana using laboratory tests and Single-Photon Emission-Computed Tomography, synchronized with electrocardiogram, known as gated SPECT (gSPECT). Coronary angiography was used for confirmation when gSPECT detected ischemia. Patients were classified into two groups: gSPECT positive and gSPECT negative. Descriptive statistics (mean and standard deviation) were calculated for all variables and mean comparison tests were conducted. Classification trees were developed relating lipid values to gSPECT results, identifying optimal cutoff points for their use as indicators of silent myocardial ischemia in the total study population and for each sex separately. RESULTS GSPECT found silent myocardial ischemia in 29.1% of those examined...