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1.
Ann Cardiol Angeiol (Paris) ; 57(1): 1-9, 2008 Feb.
Artigo em Francês | MEDLINE | ID: mdl-18280454

RESUMO

INTRODUCTION: Acute pericarditis is a frequent hospitalization cause. A prospective, bicentric study aimed at different goals: population description, aetiologies screening, and evaluation of the interest of a coordinated and combined management between cardiologists and internists. PATIENTS AND METHODS: Between May 2005 and September 2007, all patients admitted for acute pericarditis were prospectively enrolled. Physical examination, ECG, echocardiography, biological screening were performed. Patients were asked to consult both cardiologist and internist, one month later. RESULTS: Hundred and three patients were enrolled (mean age 43 years). Clinical outcome was classical in 60% of cases. ECG was typical in 59%. Troponin elevation was noted in 30% of patients. CRP was normal at diagnosis in 27% of patients, and increased significantly at first day (P=0.002). Possible cause was identified in 44 patients. In 26 patients (24.3%), precise diagnosis was performed: six cancers, one hemopathy, three connectivities, one EBV and one parvovirus B19 seroconversions, two untreated HIV patients, four inflammatory diseases, three endocrinology troubles, one oesophagitis, one dental sepsis, one amyloidosis, one acute pancreatitis, one declined dialysis indication. Eighteen de novo diagnoses (16.5%) were performed, out of them at least 12 benefited from specific management. CONCLUSION: Population of patients admitted for acute pericarditis are very heterogeneous. Our co-management between internists and cardiologists aims to diagnose earlier and easier curable diseases. Long-term follow-up remains of great interest, in order to diagnose later other disorders, which remained hidden, and to follow evolution of the population.


Assuntos
Pericardite/diagnóstico , Pericardite/etiologia , Doença Aguda , Adulto , Proteína C-Reativa/análise , Ecocardiografia , Eletrocardiografia , Feminino , Humanos , Masculino , Estudos Prospectivos , Troponina/sangue
2.
Ann Cardiol Angeiol (Paris) ; 66(4): 223-229, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28647057

RESUMO

INTRODUCTION: Increased evidence has shown that, despite the maximum care afforded to patients admitted with acute coronary syndromes (ACS), a residual risk of mortality remains, in which obstructive sleep apnoea (OSA) appears to be a largely undiagnosed factor, particularly in the intensive cardiac care unit (ICCU). The purpose of this study is to determine whether the systematic screening for sleep-disordered breathing (SDB) is feasible and may be recommended. The aims of our study are to determine: (1) The estimated prevalence of OSA in patients admitted to the ICCU for ACS determined by a validated, user-friendly portable screening device; (2) The feasibility of the screening in this context; (3) To assess any negative impact of OSA on the severity of ACS. PATIENTS AND METHODS: This is an observational study of 101 patients admitted to the ICCU for ACS showing no clinical evidence of heart failure (HF). In the 24-72hours following admission, they underwent an overnight sleep study using a 3-channel portable screening device with automatic analysis. RESULTS: Sixty-two out of the 101 patients proved positive to the screening test, and its feasibility was acceptable. OSA patients tended to have greater peak levels of hs-cTnT (3685±3576ng/L versus 2830±3333ng/L, P=0.08) than the non-OSA group. Compared with the non-OSA group, OSA patients presented more severe ACS, with a greater average GRACE score at admission of 112.2±26.3 (versus 98.4±19.2, P<0.001). In the OSA group, we found a statistically significant inverse correlation between the apnoea-hypopnea index (AHI) and the left ventricular ejection fraction (LVEF) in the linear regression analysis (r=-0.26; P=0.037). CONCLUSIONS: A systematic screening of patients in the ICCU is acceptable. OSA is frequently found in the acute phase of ischaemic heart disease and its presence is associated with more severe ACS and a poorer left ventricle systolic function.


Assuntos
Síndrome Coronariana Aguda/complicações , Apneia Obstrutiva do Sono/complicações , Apneia Obstrutiva do Sono/epidemiologia , Unidades de Cuidados Coronarianos , Feminino , Humanos , Unidades de Terapia Intensiva , Masculino , Pessoa de Meia-Idade , Prevalência , Apneia Obstrutiva do Sono/diagnóstico
3.
J Am Coll Cardiol ; 8(2): 327-32, 1986 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-3734254

RESUMO

To investigate the influence of lidocaine on the energy requirements for internal defibrillation, lidocaine (n = 8) or saline solution (n = 12) was administered by intravenous infusion to 20 pentobarbital-anesthetized dogs, and the likelihood of successful defibrillation was examined at various shock energy levels before and after treatment. After lidocaine administration to a mean steady state concentration of 5.6 +/- 2.7 micrograms/ml, the mean energy required to achieve 50 and 90% success in defibrillation (E50 and E90) increased by 61.1 +/- 34.1% (mean +/- SD, p less than 0.005) and 47.1 +/- 28.6% (p less than 0.005), respectively. The steady state log lidocaine concentration correlated positively with the observed increase in E50 (r = 0.887, p less than 0.01) over a concentration range from 1.95 to 9.8 micrograms/ml. In a related experiment, lidocaine infusion was administered to five dogs and then abruptly discontinued. At energy levels achieving a mean 90.0 +/- 10.0% success in defibrillation before treatment, only 43.3 +/- 23.4% success was achieved after 60 minutes of the lidocaine infusion (p less than 0.01) at a mean plasma concentration of 8.4 +/- 2.1 micrograms/ml. The percent of successful defibrillations returned to baseline value (92.0 +/- 18.0%, p less than 0.01) after drug washout at a time when mean lidocaine concentration had declined to 1.8 +/- 0.5 microgram/ml. Lidocaine causes a reversible, concentration-dependent increase in the energy requirements for successful defibrillation; recommendations to administer lidocaine to patients with ventricular fibrillation resistant to defibrillation may need to be reviewed.


Assuntos
Cardioversão Elétrica/métodos , Lidocaína/farmacologia , Fibrilação Ventricular/fisiopatologia , Animais , Cães , Relação Dose-Resposta a Droga , Quinidina/farmacologia
4.
J Am Coll Cardiol ; 26(3): 787-92, 1995 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-7642874

RESUMO

OBJECTIVES: The arrhythmogenic and electrophysiologic properties of sotalol, a class III antiarrhythmic drug, administered alone and in combination with mexiletine, a class I antiarrhythmic drug, were compared in conscious dogs predisposed to torsade de pointes arrhythmias. BACKGROUND: The utility of sotalol is limited by proarrhythmia related to excessive delays in repolarization. The addition of mexiletine may limit the risk of torsade de pointes because it reduced in vitro the sotalol-induced increase in action potential duration. METHODS: Two studies were performed in eight hypokalemic dogs (plasma potassium level < or = 3.2 mmol/liter) with chronic atrioventricular block (mean ventricular cycle length, RR 1,100 ms) at 3-day intervals using a crossover protocol. Intravenous sotalol (4.5 + 1.5 mg/kg body weight per h) alone was given for 2 h, or, on another day, an intravenous mexiletine infusion (4.5 + 1.5 mg/kg per h) was begun 30 min before sotalol infusion. Spontaneous ventricular cycle length and QT interval and ventricular effective refractory period at the 1,000-ms pacing cycle length were measured at baseline and 30 min after the onset of each drug infusion. The electrocardiogram (ECG) was continuously monitored for torsade de pointes. RESULTS: Sotalol plus mexiletine and sotalol alone had a significant (p < or = 0.05) and similar effect on ventricular cycle length (+ 800 +/- 93 vs. + 690 +/- 104 ms [mean +/- SEM]) and ventricular effective refractory period (+ 20 +/- 4 vs. + 25 +/- 4 ms), but sotalol plus mexiletine had a lesser effect on QT interval (+ 20 +/- 6 vs. + 50 +/- 8 ms, p < or = 0.05). Torsade de pointes is less frequent (one of eight dogs vs. six of eight dogs, p = 0.02) with sotalol plus mexiletine than with sotalol alone. CONCLUSIONS: The coadministration of a class Ib agent can reduce the proarrhythmic potential of a class III drug in experimental animals predisposed to torsade de pointes arrhythmias and further suggests the clinical utility of such a strategy.


Assuntos
Modelos Animais de Doenças , Eletrocardiografia/efeitos dos fármacos , Mexiletina/uso terapêutico , Sotalol/antagonistas & inibidores , Sotalol/uso terapêutico , Torsades de Pointes/tratamento farmacológico , Análise de Variância , Animais , Cães , Avaliação Pré-Clínica de Medicamentos , Interações Medicamentosas , Quimioterapia Combinada , Eletrocardiografia/métodos , Eletrofisiologia , Torsades de Pointes/fisiopatologia
5.
J Am Coll Cardiol ; 36(3): 871-7, 2000 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-10987613

RESUMO

OBJECTIVES: The objective of this study was to determine whether a small-size valve prosthesis contributes to exercise intolerance, as assessed by VO2 measurement during an exhaustive cycle ergometer exercise. BACKGROUND: The determinants of exercise capacity after mechanical aortic replacement are not well known. The selection of small valve sizes has, however, been described as an independent predictor of exercise intolerance as assessed by exercise duration. Maximal oxygen uptake (VO2max) is a good index of exercise tolerance. METHODS: Fourteen patients were eligible, with a mean age of 62 +/- 6 years. Before surgery, the mean left ventricular ejection fraction (LVEF) was 73 +/- 8%. Two valve types with small diameter (19 to 21 mm) were used: Medtronic Hall and St Jude Medical. A healthy sedentary control group (n = 14) paired for age, weight and size was constituted. After one year of follow-up, cardiorespiratory tests were performed. In addition, the gradients through the prostheses were determined by continuous pulse Doppler at rest and immediately after the cardiorespiratory test. RESULTS The exercise tolerance was not significantly different between the control group and patient group: VO2 peak (21.7 vs. 20.4 ml/kg/min; p = 0.42), workloads (115 vs. 93 W; p = 0.13) and ventilatory parameters were similar. The mean and peak gradients at rest and during exercise were not correlated with VO2max. CONCLUSIONS: Valve replacement by small aortic prosthesis does not seem to be a factor of exercise intolerance as assessed by VO2max in patients without LVEF dysfunction before surgery.


Assuntos
Valva Aórtica/cirurgia , Doenças das Valvas Cardíacas/cirurgia , Implante de Prótese de Valva Cardíaca , Próteses Valvulares Cardíacas , Resistência Física , Idoso , Antropometria , Ecocardiografia Doppler , Desenho de Equipamento , Teste de Esforço , Feminino , Hemodinâmica , Humanos , Masculino , Pessoa de Meia-Idade , Período Pós-Operatório , Espirometria
6.
Arch Mal Coeur Vaiss ; 98 Spec No 5: 27-33, 2005 Dec.
Artigo em Francês | MEDLINE | ID: mdl-16433240

RESUMO

Faced with a cardiac arrhythmia occuring in an apparently healthy heart, it is necessary to perform an anatomical investigation to detect any unsuspected anomalies. Congenital cardiopathy must certainly be excluded, as this is often responsible for rhythm disorders and/or cardiac conduction defects. Similarly, any acquired conditions, cardiomyopathy, or cardiac tumour must be sought. However, the possibility should always be considered of a minimal congenital malformation, which could be repsonsible for: any type of cardiac arrhythmia: rhythm disorder or conduction defect at the atrial, junctional or ventricular level, with a benign or serious prognosis. Unexpected therapeutic difficulties during radiofrequency ablation procedures or at implantation of pacemakers or defibrillators. Together with rhythm studies, the investigation of choice is high quality imaging, either the classic left or right angiography or the more modern cardiac CT or intracardiac mapping.


Assuntos
Arritmias Cardíacas/etiologia , Cardiopatias Congênitas/fisiopatologia , Anomalias dos Vasos Coronários , Aneurisma Cardíaco/fisiopatologia , Frequência Cardíaca , Humanos
7.
Rev Mal Respir ; 32(10): 1072-81, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26611197

RESUMO

The preliminary results of the SERVE-HF study have led to the release of safety information with subsequent contraindication to the use of adaptive servo-ventilation (ASV) for the treatment of central sleep apnoeas in patients with chronic symptomatic systolic heart failure with left ventricular ejection fraction (LVEF) ≤ 45%. The aim of this article is to review these results, and to provide more detailed arguments based on data from the literature advocating the continued use of ASV in different indications, including heart failure with preserved LVEF, complex sleep apnoea syndrome, opioid-induced central sleep apnea syndrome, idiopathic central SAS, and central SAS due to a stroke. Based on these findings, we propose to set up registers dedicated to patients in whom ASV has been stopped and in the context of the next setting up of ASV in these specific indications to ensure patient safety and allow reasoned decisions on the use of ASV.


Assuntos
Respiração Artificial/métodos , Apneia do Sono Tipo Central/terapia , Prova Pericial , Insuficiência Cardíaca/etiologia , Insuficiência Cardíaca/prevenção & controle , Humanos , Apneia do Sono Tipo Central/complicações
8.
Rev Med Interne ; 36(10): 677-89, 2015 Oct.
Artigo em Francês | MEDLINE | ID: mdl-26003377

RESUMO

Drug-induced adverse effects are one of the main avoidable causes of hospitalization in older people. Numerous lists of potentially inappropriate medications for older people have been published, as national and international guidelines for appropriate prescribing in numerous diseases and for different age categories. The present review describes the general rules for an appropriate prescribing in older people and summarizes, for the main conditions encountered in older people, medications that are too often under-prescribed, the precautions of use of the main drugs that induce adverse effects, and drugs for which the benefit to risk ratio is unfavourable in older people. All these data are assembled in educational tables designed to be printed in a practical pocket format and used in daily practice by prescribers, whether physicians, surgeons or pharmacists.


Assuntos
Idoso , Prescrições de Medicamentos , Padrões de Prática Médica , Fatores Etários , Idoso de 80 Anos ou mais , Prescrições de Medicamentos/normas , Prescrições de Medicamentos/estatística & dados numéricos , Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos/epidemiologia , Humanos , Prescrição Inadequada/prevenção & controle , Prescrição Inadequada/estatística & dados numéricos , Erros de Medicação/prevenção & controle , Erros de Medicação/estatística & dados numéricos , Padrões de Prática Médica/estatística & dados numéricos
9.
J Clin Endocrinol Metab ; 66(4): 762-9, 1988 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-3346355

RESUMO

Thyroid iodine content (TIC) was measured by x-ray fluorescence in 68 patients who had received amiodarone treatment for varying intervals (1 g/week for 1-120 months). Thirty-six patients were euthyroid; the mean TIC of the patients (n = 15), who had been treated for less than 12 months was 30 +/- 19 (+/- SD) mg, twice the normal mean value (14.6 +/- 5.0 mg), and it was 39 +/- 17 mg in those (n = 16) who had been treated for 12-60 months and 29 +/- 6 mg in those (n = 5) who had been treated longer (greater than 60 months). Nineteen patients were hyperthyroid and had elevated TIC values. Of them, 6 patients had a goiter; their TIC (50 +/- 19 mg) was not significantly different from that of the hyperthyroid patients with no goiter (55 +/- 29 mg), but they became hyperthyroid more rapidly. Thirteen patients were hypothyroid; none had TIC values above the normal range, and it was below 2.5 mg in 5 patients. A sequential study was undertaken in 11 euthyroid patients who had no detectable antithyroid antibodies. TIC did not increase during treatment in 2 patients; both developed hypothyroidism, which was transient in 1 despite continuation of amiodarone treatment. The TIC initially increased during amiodarone treatment in the other 9 patients, leveling off at the end of the first year. The TIC rose well above the upper limit of the normal range in 4 patients, of whom 2 became hyperthyroid during the second year of treatment. TIC remained within the normal range in the other 5 patients, of whom 3 became hypothyroid after 12-24 months of treatment (1 subclinical, 2 overt). Although the TIC was significantly higher in the patients with hyperthyroidism than in the patients who remained euthyroid, the TIC test cannot be used to predict the occurrence of hyperthyroidism. The latter must be diagnosed on the basis of clinical symptoms and a frank elevation of serum thyroid hormone levels. Conversely, patients whose TIC values do not increase during treatment or remain within the normal range should be considered at risk for hypothyroidism.


Assuntos
Amiodarona/uso terapêutico , Hipertireoidismo/induzido quimicamente , Hipotireoidismo/induzido quimicamente , Iodo/análise , Glândula Tireoide/análise , Adulto , Idoso , Idoso de 80 Anos ou mais , Amiodarona/efeitos adversos , Arritmias Cardíacas/tratamento farmacológico , Feminino , Humanos , Hipertireoidismo/sangue , Hipotireoidismo/sangue , Iodo/sangue , Masculino , Pessoa de Meia-Idade , Espectrometria por Raios X , Glândula Tireoide/efeitos dos fármacos , Hormônios Tireóideos/sangue
10.
Am J Cardiol ; 80(1): 6-10, 1997 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-9205011

RESUMO

Dobutamine echocardiography (5 and 10 microg/kg/ min) was performed in 40 patients 4 +/- 1 days after acute myocardial infarction reperfused by primary coronary angioplasty. The left ventricle was divided into 11 segments. Reversible myocardial dysfunction was indicated by a decrease in at least 2 grades in the total segmental score. Follow-up echocardiography was performed 2 months later. Contractile reserve was documented in 18 patients with dobutamine echocardiography (45%). Sensitivity, specificity, positive, and negative predictive value of dobutamine echocardiography in predicting improvement in contractile function at follow-up were 82%, 83%, 78%, and 86%, respectively. Negative predictive value was high in all dyssynergic segments (86%). Positive predictive value was higher in hypokinetic than in akinetic segments (73% vs 21%; p <0.05). Recovery of wall motion at follow-up was statistically associated with higher left ventricular ejection fraction (p <0.04), collateral blood flow before reperfusion (p = 0.007), and dobutamine responsiveness (p = 0.0001), and was more frequently observed in hypokinetic than in akinetic segments (p <0.05). Thus, low-dose dobutamine echocardiography accurately predicts the extent of irreversibly damaged myocardium early after successful direct coronary angioplasty in acute myocardial infarction.


Assuntos
Dobutamina , Ecocardiografia/métodos , Infarto do Miocárdio/diagnóstico , Infarto do Miocárdio/terapia , Idoso , Angioplastia Coronária com Balão , Cateterismo Cardíaco , Angiografia Coronária , Teste de Esforço , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Contração Miocárdica , Valor Preditivo dos Testes , Sensibilidade e Especificidade
11.
Eur J Heart Fail ; 1(4): 353-61, 1999 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-10937948

RESUMO

UNLABELLED: The aims of the study were to analyze the clinical features, the penetrance and the mode of inheritance of 13 French families with dilated cardiomyopathy using diagnostic criteria recently established by a European collaboration. METHODS: Screening consisted of physical examination, ECG and Echo of all the probands first degree relatives (n = 118). Using major Echo criteria [ejection fraction (EF) < 45% or FS < 25% and left ventricular diameter (LVD) > 117% of the predictive value], or combined minor Echo/ECG criteria, relatives were classified as affected, unknown or healthy. RESULTS: (1) Adult affected relatives (n = 31) were identified with major Echo criteria in 74% of cases, and with combined minor Echo/ECG criteria in 26% of cases. (2) In the unknown relatives (n = 21), the most common abnormality was an isolated left ventricular dilation (67%). (3) Mode of inheritance was autosomal dominant (AD) in 11 families and possibly autosomal recessive in two. (4) In AD families, the penetrance was incomplete in adults (72%), age-related (O.R.: 1.3 per 10 years; 95% CI 1.03-1.56) and sex-related [greater in men (87%) than in women (61%), actuarial survival curve: P<0.002]. (5) Mortality related to end stage heart failure was 2.2 times as high as mortality related to sudden death (11% vs. 5%). CONCLUSIONS: (1) In the absence of a specific phenotype of FDC, the characterization of relatives appears more accurate when minor criteria were added. (2) Since high mortality (16%) and incomplete penetrance frequently give rise to small nuclei of clinically affected and alive relatives per family, the accurate model of penetrance that we proposed might be helpful in the future to enhance the statistical power of linkage analysis in this disease.


Assuntos
Cardiomiopatia Dilatada/genética , Adulto , Cardiomiopatia Dilatada/diagnóstico , Cardiomiopatia Dilatada/mortalidade , Ecocardiografia , Eletrocardiografia , Feminino , França/epidemiologia , Humanos , Masculino , Pessoa de Meia-Idade , Linhagem , Volume Sistólico , Taxa de Sobrevida
12.
Heart ; 82(1): 62-7, 1999 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-10377311

RESUMO

OBJECTIVE: To evaluate the combined assessment of reflow and collateral blood flow by myocardial contrast echocardiography after myocardial infarction. DESIGN: Myocardial contrast echocardiography was performed in patients with acute myocardial infarction shortly after successful coronary reperfusion (TIMI 3 patency) by direct angioplasty. Collateral flow was assessed before coronary angioplasty, and contrast reflow was evaluated 15 minutes after reperfusion. The presence of contractile reserve was assessed by low dose dobutamine echocardiography (5 to 15 micrograms/kg/min) at (mean (SD)) 3 (2) days after myocardial infarction. Recovery of segmental function (myocardial viability) was evaluated by resting echocardiography at a two month follow up. The study was prospective. PATIENTS: 35 consecutive patients referred for acute transmural myocardial infarction. RESULTS: Contrast reflow was observed in 20 patients (57%) and collateral flow in 14 (40%). Contrast reflow and collateral contrast flow were both correlated with reversible dysfunction on initial dobutamine echocardiography and at follow up (p < 0.05). The presence of reflow or collateral flow on myocardial contrast echocardiography was a highly sensitive (100%) but weakly specific (60%) indicator of segmental dysfunction recovery. Simultaneous presence of contrast reflow and collateral flow was more specific of reversible dysfunction than reflow alone (90% v 60%). CONCLUSIONS: Combined assessment of reflow and collateral blood flow enhanced the sensitivity of myocardial contrast echocardiography in predicting myocardial viability after acute, reperfused myocardial infarction. The simultaneous presence of reflow and collateral blood flow was highly specific of recovery of segmental dysfunction.


Assuntos
Circulação Colateral , Circulação Coronária , Ecocardiografia , Infarto do Miocárdio/fisiopatologia , Adulto , Idoso , Angioplastia Coronária com Balão , Cardiotônicos/uso terapêutico , Dobutamina , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Infarto do Miocárdio/diagnóstico por imagem , Infarto do Miocárdio/terapia , Prognóstico
13.
J Pharmacol Toxicol Methods ; 29(1): 45-57, 1993 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-8481561

RESUMO

The canine model of ventricular tachycardias (VT) induced by programmed stimulation is used routinely in several laboratories to test antiarrhythmic drugs. The aim of the present study was to determine the rate of success and reproducibility of this model. We analyzed a group of 58 dogs that underwent a 2-hr occlusion and were submitted to programmed electrical stimulation at least 4 days after the surgery. Only 29 dogs (50%) were inducible and included in the study, as 22 dogs died following myocardial infarction, and seven dogs were never inducible. Out of 130 trials, 92 (70%) performed on inducible dogs were positive with 11% of nonsustained ventricular tachycardias, 63% of sustained monomorphic ventricular tachycardias, and 26% of ventricular fibrillation. Inducibility decreased over time in a subgroup of 19 dogs that was submitted to four trials during the first month after the infarction (68% of inducible dogs versus 46% in trials 1 and 4, respectively). Ventricular effective refractory period decreased significantly from 146 +/- 7 msec at trial 1 to 114 +/- 6 msec at trial 4, and the severity of the induced ventricular tachycardias increased. This variability should be considered when planning studies on antiarrhythmic drugs in this model.


Assuntos
Modelos Animais de Doenças , Estimulação Elétrica , Taquicardia Ventricular/fisiopatologia , Animais , Antiarrítmicos/farmacologia , Cães , Eletrofisiologia , Feminino , Masculino , Infarto do Miocárdio/tratamento farmacológico , Infarto do Miocárdio/fisiopatologia , Reprodutibilidade dos Testes , Taquicardia Ventricular/tratamento farmacológico , Fatores de Tempo
14.
Life Sci ; 35(9): 937-45, 1984 Aug 27.
Artigo em Inglês | MEDLINE | ID: mdl-6332257

RESUMO

Positron Emission Tomography (PET) was used to analyse in vivo antagonist binding to human myocardial muscarinic cholinergic receptor. The methiodide salt of the muscarinic antagonist, quinuclidinyl benzilate (MQNB), was labeled with the positron emitter, Carbon-11, and injected intravenously to 8 normal subjects. 11C-MQNB concentration was determined in vivo in the ventricular septum from 40 cross-sectional images acquired at the same transverse level over a period of 70 minutes. In 4 subjects, various amounts of unlabeled atropine were rapidly injected at 20 minutes to study whether atropine competitively inhibited MQNB. The kinetics of binding of 11C-MQNB were not the same in vivo and in vitro. The apparent dissociation rate of 11C-MQNB in vivo was much slower (by 1 to 2 orders of magnitude) than that observed in vitro with 3H-QNB. After atropine injection, 11C-MQNB dissociated from its binding sites at a rate that apparently depended on the amount of atropine present. 11C-MQNB kinetics were analysed with a mathematical model which assumes the existence of a boundary layer containing free ligand in the vicinity of the binding sites. The dissociation rate of the radioligand depends on the probability of its rebinding to a free receptor site.


Assuntos
Miocárdio/metabolismo , Quinuclidinas/metabolismo , Quinuclidinil Benzilato/metabolismo , Receptores Muscarínicos/metabolismo , Tomografia Computadorizada de Emissão , Atropina/farmacologia , Ligação Competitiva , Humanos , Cinética , Masculino , Matemática , Modelos Biológicos
15.
Fundam Clin Pharmacol ; 7(1): 29-38, 1993.
Artigo em Inglês | MEDLINE | ID: mdl-8458600

RESUMO

Torsades de pointes is the most typical ventricular tachycardia involving QT-interval prolongation. It is a rather unusual but potentially lethal ventricular tachycardia with a distinctive morphology favored by bradycardia, antiarrhythmic drugs and hypokalemia and requires specific treatment. Torsades de pointes has been shown to be related to bradycardia-dependent early afterdepolarizations (EAD) and/or increased dispersion of repolarization. However, although EAD can be obtained relatively easily in vitro with quinidine or sotalol, torsades de pointes are very difficult to reproduce in animal models. The models of torsades de pointes which have been proposed can be categorized as morphological, EAD-related or pharmacological models. The purpose of the 'morphological' models was to reproduce the twisting of QRS axis typical of torsades de pointes, with no consideration of other aspects such as long QT or bradycardia. These models were produced by epicardial electrical or chemical (aconitine) stimulation at two distant ventricular sites or by overdosing of quinidine in dogs with acute myocardial infarction. The second type of model focused on the conditions producing EAD in vitro. Ventricular tachycardias were obtained in anesthetized dogs using toxics such as cesium or anthopleurine, both producing EAD in vitro. These ventricular tachycardias were shown to be sensitive to magnesium, heart rate and autonomic tone, but torsades de pointes remained rare, at least after cesium injections. The pharmacological models that could be used to study the QT-dependent proarrhythmic effects of drugs are the anesthetized rabbit with alpha-adrenergic stimulation, and the conscious dog model with chronic AV-block and diuretic-induced hypokalemia. Methoxamine-treated anesthetized rabbits develop ventricular tachycardias during clofilium infusions. These ventricular tachycardias, although appearing at very high heart rates, have typical torsades de pointes aspects and are often associated with giant QT waves. The specificity of the model remains to be tested. In our conscious bradycardic and hypokalemic dogs, quinidine and sotalol but not flecainide, propranolol or lidocaine induced QT-dependent arrhythmogenic effects and torsades de pointes. Efficacy of high rate stimulations and magnesium were repeatedly observed. This demanding model, especially designed for qualitative drug comparisons, is also well suited to studies on the mechanisms of initiation of torsades de pointes. The pertinence of these models for estimating the risk of QT-dependent proarrhythmias associated with non-antiarrhythmic agents remains to be tested.


Assuntos
Torsades de Pointes/fisiopatologia , Animais , Modelos Animais de Doenças , Humanos , Torsades de Pointes/induzido quimicamente
16.
Fundam Clin Pharmacol ; 9(3): 240-7, 1995.
Artigo em Inglês | MEDLINE | ID: mdl-7557819

RESUMO

The proarrhythmic effects of 3-hydroxy-hydroquinidine (3-OH-HQ) and quinidine were compared in a canine model of QT-dependent ventricular arrhythmias. Eight hypokalemic ([K+] < or = 3.2 mmol/l) dogs with AV block (around 45 bpm) were given either drug in a randomized order at 2-day intervals. Each drug was given as two 1 hour doses, with a bolus (low dose: 5 mg/kg or high dose: 10 mg/kg) plus infusion (25 or 50 micrograms/kg/min) protocol. Propranolol infusion was combined with a third hour of the high dose infusion. Electrophysiologic measurements were performed at baseline and 30 minutes after the beginning of each dose and propranolol infusion, and proarrhythmic events were recorded 30 minutes before and during the experiment. Neither drugs altered the ventricular cycle length. Quinidine and 3-OH-HQ prolonged the QT interval similarly and significantly when paced at 60 bpm after the low dose (+39 +/- 18 and +28 +/- 22 msec, respectively) and after the high dose (+51 +/- 29 and +50 +/- 22 msec). Quinidine was more arrhythmogenic than 3-OH-HQ: 7/8 dogs (p < or = 0.05) developed ventricular arrhythmias (isolated, repetitive ventricular beats, or polymorphic ventricular tachycardias) during quinidine infusion (low dose: 4 dogs) compared to 3/8 dogs (NS) during 3-OH-HQ infusion (low dose: 1 dog). Addition of propranolol-induced bradycardia (around 30 bpm) caused torsades de pointes (wave burst arrhythmias) or polymorphic ventricular tachycardias after both drugs (in 3 dogs after quinidine and in 2 dogs after 3-OH-HQ). Thus 3-OH-HQ was slightly less arrhythmogenic than quinidine in this model of torsades de pointes, but the addition of an extra favouring factor (bradycardia) reduced that difference.


Assuntos
Arritmias Cardíacas/induzido quimicamente , Quinidina/análogos & derivados , Antagonistas Adrenérgicos beta/farmacologia , Animais , Arritmias Cardíacas/fisiopatologia , Complexos Cardíacos Prematuros/induzido quimicamente , Complexos Cardíacos Prematuros/fisiopatologia , Cães , Eletrocardiografia/efeitos dos fármacos , Eletrofisiologia , Frequência Cardíaca/efeitos dos fármacos , Frequência Cardíaca/fisiologia , Propranolol/farmacologia , Quinidina/antagonistas & inibidores , Quinidina/toxicidade , Taquicardia Ventricular/fisiopatologia
17.
Coron Artery Dis ; 8(8-9): 537-41, 1997.
Artigo em Inglês | MEDLINE | ID: mdl-9431482

RESUMO

BACKGROUND: The cardiac isoform of troponin I (cTnI) is a myofibrillar protein highly specific for myocardial injury. We used a recently developed new-generation immunoassay with high analytical sensitivity to measure cTnI in patients diagnosed with hematologic malignancies, before chemotherapy and after an intermediate cumulative dose of anthracyclines. We hypothesized that measurement of cTnI with this sensitive method would provide evidence of myocardial injury in these patients. METHODS: Sera from 115 individuals (60 healthy controls, 25 anthracycline-naive patients and 30 patients treated with intermediate cumulative doses of anthracyclines) were assessed for cTnI, creatine kinase MB (CKMB) mass and myoglobin. Radionuclide left ventricular ejection fraction (LVEF) was also determined. RESULTS: Using this sensitive assay, detectable concentrations of cTnl were measured in the healthy population [mean, 19.5 pg/ml, 95% confidence interval (CI) 13.5-25.5 pg/ml]. Anthracycline-naive patients had cTnI mean values (36.5 pg/ml, 95% CI 25.1-47.9 pg/ml) that were significantly (P < 0.01) greater than those in the control group. cTnI was significantly (P < 0.00001) increased in anthracycline-treated patients (76.4 pg/ml, 95% CI 67.0-85.8 pg/ml) compared with both the anthracycline-naive patients and the controls. CKMB, myoglobin and LVEF were within the normal range in all patients. CONCLUSIONS: These data provide evidence for cardiac involvement in patients with hematological malignancies before and during the course of anthracycline chemotherapy. They suggest that detection of myocardial injury may be facilitated by measurement of cTnI with a highly sensitive assay.


Assuntos
Antibióticos Antineoplásicos/efeitos adversos , Cardiomiopatias/diagnóstico , Neoplasias Hematológicas/tratamento farmacológico , Troponina I/sangue , Adulto , Idoso , Antibióticos Antineoplásicos/uso terapêutico , Biomarcadores/análise , Cardiomiopatias/sangue , Cardiomiopatias/etiologia , Creatina Quinase/análise , Creatina Quinase/efeitos dos fármacos , Relação Dose-Resposta a Droga , Feminino , Coração/efeitos dos fármacos , Neoplasias Hematológicas/sangue , Neoplasias Hematológicas/complicações , Humanos , Masculino , Pessoa de Meia-Idade , Mioglobina/análise , Mioglobina/efeitos dos fármacos , Radioimunoensaio , Sensibilidade e Especificidade , Volume Sistólico/efeitos dos fármacos , Troponina I/análise
18.
Arch Mal Coeur Vaiss ; 87(1 Spec No): 41-6, 1994 Jan.
Artigo em Francês | MEDLINE | ID: mdl-7524461

RESUMO

There are many electrocardiographic changes in sinoatrial block. Only 2nd and 3rd degree blocks can be analysed on surface recordings. However, they manifest themselves by pauses, the descriptions of which are rich and varied. They also vary according to the circumstances of apparition and the escape rhythms which accompany them. Related ECG changes such as chronotropic insufficiency or carotid sinus syndrome have been described. However, their significance is not univocal and only a precise analysis of the ECG recordings allows correct interpretation of the clinical and paraclinical signs and the institution of appropriate therapy.


Assuntos
Eletrocardiografia , Bloqueio Sinoatrial/fisiopatologia , Complexos Cardíacos Prematuros/fisiopatologia , Humanos , Taquicardia/fisiopatologia
19.
Arch Mal Coeur Vaiss ; 91(12 Suppl): 27-30, 1998 Dec.
Artigo em Francês | MEDLINE | ID: mdl-9891818

RESUMO

The hypothesis of immune and inflammatory activation occurring during chronic cardiac failure, capable of maintaining the disease, is supported by many experimental and clinical trials. Plasma cytokines levels, particularly the tumour necrosis factor alpha (TNF alpha), are raised at advanced stages of the disease, especially in cachectic patients. The correlations with other, more traditional markers, especially neurohumoral, are not very close, probably suggesting different mechanisms. Cytokines are a group of very different molecules with multiple, non-specific, and even beneficial effects. However, the lack of regulation in severe cardiac failure may lead to deleterious effects on the heart. The experimental effects of TNF alpha (mini-pumps, transgenic animals) include features of myocarditis, chamber dilatation and contractile dysfunction. Large scale therapeutic trials of long acting TNF alpha antagonists could confirm the "inflammation hypothesis" of mutual interaction between cardiac failure and the production of cytokines.


Assuntos
Baixo Débito Cardíaco/fisiopatologia , Citocinas/fisiologia , Citocinas/genética , Progressão da Doença , Humanos , Inflamação/fisiopatologia , Família Multigênica , Fator de Necrose Tumoral alfa/fisiologia
20.
Arch Mal Coeur Vaiss ; 73(6): 737-45, 1980 Jun.
Artigo em Francês | MEDLINE | ID: mdl-6779768

RESUMO

A 25 year old patient presented with several types of paroxysmal tachycardia. Analysis of the recordings and the results of endocavitary electrophysiological investigation suggest the presence of nodoventricular and atrio-ventricular fibres. These two accessory pathways were latent in sinus rhythm but formed part of reentry loops. The reciprocating rhythms used the Kent bundle in the retrograde direction, and either the normal nodo-hisian or the Mahaim fibres in the anterograde direction. Simple echos ascending by the nodo-hisian pathway and descending by the nodo-ventricular pathway were also observed. The patient died of an unassociated cause and a pathological examination of the heart was performed. This confirmed the presence of a left posterior paraseptal Kent bundle and the presence of fibres relaying the inferior part of the atrioventricular node to the septal ventricular myocardium, this being made possible by a dehiscence of the central fibrous body.


Assuntos
Nó Atrioventricular/fisiopatologia , Sistema de Condução Cardíaco/fisiopatologia , Ventrículos do Coração/fisiopatologia , Taquicardia Paroxística/fisiopatologia , Adulto , Eletrofisiologia , Ventrículos do Coração/patologia , Humanos , Masculino
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