RESUMO
BACKGROUND: Limited knowledge exists on vascular risk factors, body height and weight in patients with spontaneous cervical artery dissection (sCAD). PATIENTS AND METHODS: In this case-control study, major vascular risk factors, body weight, body height and body mass index (BMI) of 239 patients obtained from a prospective hospital-based sCAD registry were compared with 516 age- and sex-matched healthy controls undergoing systematic health examinations in the Clinical and Preventive Investigations Center, Paris. Gender-specific analyses were performed. RESULTS: The mean body height was higher in sCAD patients than in controls (171.3 cm (SD 8.6) vs 167.7 cm (8.9); p<0.0001) and sCAD patients had a significantly lower mean body weight (67.5 (12.2) kg vs 69.3 (14.6) kg; p<0.001) and mean BMI (22.9 (3.3) kg/m2 vs 24.5 (4.2) kg/m2; p<0.0001) than controls. The overall frequency of hypertension, diabetes, current smoking, past smoking and hypercholesterolaemia did not differ significantly between sCAD patients and controls. The mean total plasma cholesterol level was identical in both groups (5.5 mmol/l, SD 1.1). Gender specific subgroup analyses showed similar results for men and women. CONCLUSION: Patients with sCAD had a higher body height and a lower body weight and BMI than controls, while major vascular risk factors were similar in sCAD patients and controls.
Assuntos
Transtornos Cerebrovasculares/complicações , Dissecação da Artéria Vertebral/diagnóstico , Dissecação da Artéria Vertebral/etiologia , Adulto , Angiografia Digital , Estatura , Índice de Massa Corporal , Peso Corporal , Estudos de Casos e Controles , Feminino , Humanos , Angiografia por Ressonância Magnética , Imageamento por Ressonância Magnética , Masculino , Estudos Prospectivos , Fatores de RiscoRESUMO
Sudden death is a major problem in public health, affecting around 50 000 people a year in France. The prognosis for cardiac arrest is abysmal because for every minute lost the chances of survival diminish by 10%. The aim of this work was to prospectively evaluate the characteristics of cardiac arrest victims across an entire 6000 km? area, the Seine-et-Marne district, distinguished by the paradox of lying just outside the capital whilst actually being semi-rural, and to determine the current methods of dealing with this emergency. The DEFI 77 prospective epidemiological survey was carried out with the collaboration of the SAMU emergency medical service, the SDIS fire/ambulance service, the general hospitals and the Paris-Ile-de-France cardiological association. Between January 2001 and December 2005 there were 2001 cardiac arrests (mean age 68 +/- 20 years, 67% male) at home in 80% of cases. The arrest was in front of a witness in 72% of cases, but they performed resuscitation in only 14.3% of cases. The SAMU and SMUR emergency medical services attempted cardio-pulmonary resuscitation in 78% of cases. In 29% of cases, one or more external electric shocks were carried out, using a semi-automatic defibrillator 79% of the time. Only 11.5% of patients arrived at the emergency department alive, the overall hospital survival rate being less than 2%. Only eight patients subsequently underwent automatic defibrillator implantation. The results of this observational study are to a large extent explained by an extremely long delay (12 minutes) before help was called for, the delay between the call and the arrival of medical assistance (9.5 +/- 4 min), the low percentage of active witnesses, and the variability in management (invasive in particular). In conclusion, at the dawn of the third millennium the prognosis of cardiac arrest remains very poor and fully justifies educating the general public about calling for help early and about actions that can save lives, particularly external cardiac massage before the arrival of the emergency services, as well as the benefits of using automated external defibrillators.
Assuntos
Morte Súbita Cardíaca/epidemiologia , Parada Cardíaca/mortalidade , Idoso , Idoso de 80 Anos ou mais , Serviços Médicos de Emergência , Feminino , França/epidemiologia , Inquéritos Epidemiológicos , Frequência Cardíaca , Humanos , Masculino , Pessoa de Meia-Idade , População Rural , Fatores de TempoRESUMO
AIMS: To evaluate the cardiovascular prognosis of 1845 Diabetic Patients (DP) and 6443 Non-Diabetic Patients (NDP) in secondary prevention. METHODS: Patients were recruited prospectively if they had had a previous history of ischemic stroke or acute coronary syndrome (ACS) i.e. Myocardial Infarction (MI) or Unstable Angina (UA) within a period of five years preceding inclusion. For each patient, the number of hospitalizations and vital status were recorded each month over a 6-month period (mean follow-up: 4.8 months). RESULTS: 306 patients (9.5/100--person years; 95% CI, 8.5 to 10.6) had undergone at least one subsequent event (hospitalization for ACS, ischemic stroke, or cardiovascular death). A majority of these events were non-fatal ACS (n=248). The cumulative incidence rate of subsequent events was higher in DP: 12.6/100- person years (10.0 to 15.2) than in NDP: 8.6/100--person years (7.5 to 9.8). DP were significantly at higher risk of subsequent cardiovascular events (OR: 1.34; P=0.025) after adjustment for confounding factors. 93% of coronary DP and NDP underwent a recurrent event affecting the same location. When the index episode was a stroke, 71% of DP had a subsequent stroke vs. 47% of NDP. CONCLUSION: in secondary prevention, the risk of mortality and subsequent vascular events is independently higher in French DP than in NDP. The locations affected by each type of subsequent cardiovascular event seemed correlated to the baseline diagnosis, whatever the diabetic status, even when the frequency of subsequent strokes increased (not significantly) in DP when compared to NDP.
Assuntos
Doença das Coronárias/fisiopatologia , Diabetes Mellitus/fisiopatologia , Inquéritos Epidemiológicos , Acidente Vascular Cerebral/fisiopatologia , Idoso , Idoso de 80 Anos ou mais , Estudos de Coortes , Angiopatias Diabéticas/epidemiologia , Feminino , França/epidemiologia , Humanos , Incidência , Masculino , Anamnese , Seleção de Pacientes , Fatores de Tempo , Resultado do Tratamento , Doenças Vasculares/epidemiologiaRESUMO
OBJECTIVE: The SYMFONIE study was designed to analyze the clinical and biological characteristics, and the cardiovascular risk markers, in men and women with the metabolic syndrome compared to control subjects. RESEARCH DESIGN AND METHODS: The study population included 101,697 men and women, 18 to 80 years of age, who had a health checkup at the Centre d'Investigations Preventives et Cliniques (Paris, France) between 1997 to 2002. The metabolic syndrome was defined according to the ATpiiI-NCEP 2001 criteria. RESULTS: Out of the 66,202 men (47.4+/-11.8 years) and 35,495 women (48.5+/-13.6 years) included in this population, 6761 men (10.2%) and 2155 women (6.1%) presented the metabolic syndrome. Among subjects < or =40 years of age, the prevalence of the metabolic syndrome was 5.0% in men and 2.2% in women, and rose to 14.1% and 12.0%, respectively, among men and women >70 years of age. After adjustment for age, patients with the metabolic syndrome presented higher pulse pressure (systolic minus diastolic blood pressure), higher heart rate, lower vital respiratory capacity, lower physical activity, an increase in inflammatory status assessed through leukocyte count and dental inflammation, hepatic abnormalities, and increased levels of stress and depression. CONCLUSION: In this large French population, the prevalence of the metabolic syndrome is lower than in North American and northern European populations. Patients with the metabolic syndrome present several additional hemodynamic, inflammatory and psychological risk markers which could contribute to the poor cardiovascular prognosis of these subjects.
Assuntos
Doenças Cardiovasculares/epidemiologia , Síndrome Metabólica/epidemiologia , Adulto , Consumo de Bebidas Alcoólicas/epidemiologia , Proteínas Sanguíneas/análise , Índice de Massa Corporal , Feminino , França/epidemiologia , Humanos , Masculino , Pessoa de Meia-Idade , Prevalência , Fatores de Risco , Caracteres SexuaisRESUMO
UNLABELLED: A survey into the implantation of cardiac pacemakers during 2001 in the Ile-de-France area was carried out by the French National Insurance Medical Service in order to evaluate performance in all centres performing more than 10 primary implantations per year. METHODS AND RESULTS: In 2001, 12 centres out of a total of 49 performed less than 50 primary implantations per year, representing 5% of the total regional activity, which was estimated to be 6414 procedures. The remaining 95% of procedures were spread evenly among 8 high-throughput centres (> 200 primary implantations per year) and 29 medium-throughput centres (50 to 200 primary implantations per year). Indications for pacing were analysed retrospectively by a team of regulatory doctors on a sample of 2176 patients with reference to the ACC/AHA/NASPE guidelines. After examination of the medical records, the indication was ranked as being class I, II or Ill (absence of indication). A valid indication was lacking in 8.2% of cases. Sinus node dysfunction represented 74.6% of the non-indications, and this classification had the predictive factors of asymptomatic dysfunction, and treatment with anti-arrhythmic or bradycardic medication. The proportion of class III interventions was significantly lower in the high-throughput centres (5.8 vs 9.9%, p < 0.05). CONCLUSION: 8.2% of primary pacing procedures were not indicated and resulted principally from asymptomatic sinus node dysfunction.
Assuntos
Estimulação Cardíaca Artificial/estatística & dados numéricos , Idoso , Feminino , Humanos , Masculino , Paris , Estudos Retrospectivos , Inquéritos e QuestionáriosRESUMO
BACKGROUND: The clinical presentation and causes of atrial fibrillation (AF) in the 1990s may differ from AF seen 2 to 3 decades ago. It was the objective of this prospective study to characterize various clinical presentations and underlying conditions of patients with AF observed in general practice in France. METHODS AND RESULTS: The study population comprised 756 patients (19 to 95 years of age) with electrocardiographically documented AF subdivided into paroxysmal (<7 days), chronic (last episode >1 month) and recent onset AF(persistent >7 days and<1 month). Symptoms were present in 670 patients (88.6%). The relative prevalences of paroxysmal, chronic, and recent onset AF were 22.1%, 51.4%, and 26.4%, respectively. Cardiac disorders, present in 534 patients (70.6%), included hypertension (39.4%), coronary artery disease (16.6%), and myocardial diseases (15.3%) as the most common. Rheumatic valvular disease represented a common cause in women (25. 0%) but not in men (8.0%). The paroxysmal group differed by a high percentage of palpitations (79.0%) and a low percentage of underlying heart disease (53.9%). With a mean follow-up of 8.6+/-3.7 months, 28 patients (3.7%) died, including 6 fatal cerebrovascular accidents. Among the 728 patients who survived, congestive heart failure occurred in 30 patients (4.1%), and embolic complications occurred in 13 patients (1.8%). In the paroxysmal AF group, 13 patients (8.0%) developed chronic AF and 51 (31.3%) had AF recurrences. At the time of follow-up, 53 patients (14.3%) from the chronic AF group and 108 patients (55.7%) from the recent onset AF group were in sinus rhythm. CONCLUSIONS: This large-scale study establishes the current demographic profile of out-of-hospital patients with AF and highlights some of the changes that have occurred in the past decades, including a particular shift in cardiac causes toward nonrheumatic AF. This study also demonstrates significant differences between various subsets of AF.
Assuntos
Fibrilação Atrial/classificação , Fibrilação Atrial/fisiopatologia , Medicina de Família e Comunidade/estatística & dados numéricos , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Antiarrítmicos/uso terapêutico , Anticoagulantes/uso terapêutico , Fibrilação Atrial/epidemiologia , Feminino , Seguimentos , França/epidemiologia , Humanos , Masculino , Pessoa de Meia-Idade , Reprodutibilidade dos Testes , Fatores de Risco , Fatores SexuaisRESUMO
OBJECTIVES: The goal of this study was to evaluate the role of diastolic blood pressure (DBP) in cardiovascular mortality for different systolic blood pressure (SBP) levels in middle-aged men and women. BACKGROUND: In middle-aged subjects it is unclear whether DBP, in addition to SBP, should be considered for risk evaluation. METHODS: Subjects (77,023 men; 48,480 women) aged 40 to 70 years old, had no major cardiovascular disease, no antihypertensive treatment and were examined at the Centre d'Investigations Preventives et Cliniques between 1972 and 1988. Mortality was assessed for an 8- to 12-year period. RESULTS: In both genders, cardiovascular mortality increased with the SBP level. In men and women with normal SBP levels, DBP did not influence cardiovascular mortality after adjustment for age and SBP. In men with systolic hypertension, a U-shaped curve relationship between cardiovascular mortality and DBP was observed, with the lowest mortality rates in the group with DBP 90 to 99 mm Hg. Compared with this group, age- and SBP-adjusted cardiovascular mortality was higher by 73% (p < 0.02) in the group with DBP <90 mm Hg and by 65% (p < 0.001) in the group with DBP > or =110 mm Hg. In women with systolic hypertension, however, DBP was positively correlated with cardiovascular mortality. CONCLUSIONS: In middle-aged subjects, classification of cardiovascular risk according to DBP levels should take into account gender, especially when SBP levels are elevated. Men with systolic hypertension are at higher risk when their DBP is "normal" than when they present a mild to moderate increase in DBP. In women of the same age, however, systolic-diastolic hypertension represents a higher risk than isolated systolic hypertension.
Assuntos
Pressão Sanguínea/fisiologia , Doenças Cardiovasculares/diagnóstico , Diástole/fisiologia , Hipertensão/diagnóstico , Sístole/fisiologia , Adulto , Idoso , Doenças Cardiovasculares/fisiopatologia , Feminino , Humanos , Hipertensão/fisiopatologia , Masculino , Pessoa de Meia-Idade , Fatores de RiscoRESUMO
OBJECTIVES: The study evaluated the risk of cardiovascular mortality according to combined spontaneous (non-treatment-related) changes in both systolic and diastolic blood pressure (BP). BACKGROUND: Long-term longitudinal changes in blood pressure may be a more accurate determinant of cardiovascular risk since changes in systolic or diastolic blood pressure over a period of time reflect the evolution of arterial and arteriolar alterations. METHODS: Two independent French male cohorts were studied: the IPC cohort (Investigations Préventives et Cliniques) composed of 15,561 men aged 20 to 82 years who had had two visits spaced four to 10 years apart, and the Paris Prospective Study composed of 6,246 men aged 42 to 53 years, examined annually for a period of four years. None of the subjects were taking antihypertensive medication. Annual changes in BP were estimated, and subjects were divided into groups according to the increase, lack of change, or decrease of systolic or diastolic BP. Nine groups were formed by combining the changes of systolic and diastolic BP. Cardiovascular mortality was assessed for a mean period of 13.5 years for the IPC Study and 17 years for the Paris Prospective Study. RESULTS: In both cohorts, after adjustment for age and major risk factors, the group with an increase in systolic and a decrease in diastolic BP presented the highest relative risk of cardiovascular mortality compared to the group with no changes in either systolic or diastolic BP (relative risk: 2.07 [1.05 to 4.06] in the IPC Study and 2.16 [1.16 to 4.01] in the Paris Prospective Study). CONCLUSIONS: Assessment of spontaneous changes of BP over a long period of time can contribute to the evaluation of cardiovascular risk. Subjects whose systolic BP increased while their diastolic BP decreased had the highest cardiovascular risk independently of absolute values of BP or other risk factors.
Assuntos
Pressão Sanguínea/fisiologia , Doenças Cardiovasculares/mortalidade , Adulto , Idoso , Idoso de 80 Anos ou mais , Doenças Cardiovasculares/fisiopatologia , Diástole , França/epidemiologia , Humanos , Masculino , Pessoa de Meia-Idade , Prognóstico , Estudos Prospectivos , Taxa de Sobrevida , SístoleRESUMO
OBJECTIVES: The goal of this research was to study coronary atherosclerosis in patients with type 2 diabetes compared with patients without diabetes according to the new definition of diabetes advocated by the American Diabetes Association in 1997. BACKGROUND: Patients with diabetes (fasting plasma glucose above 7.0 mM/L) have a higher risk of cardiovascular death. The correlation with the pattern and severity of their coronary atherosclerosis, especially in the new patients with "mild" diabetes (7.0 mM/L < or = fasting plasma glucose < 7.8 mM/L), remains unclear. METHODS: A cohort of 466 patients undergoing coronary angiography but free of any previous infarction, coronary intervention and insulin therapy were prospectively recruited. Ninety-three had diabetes (fasting plasma glucose > 7.0 mM/L or hypoglycemic oral treatment). Five angiographic indexes were calculated to describe severity and extent of coronary atherosclerosis. RESULTS: Overall, patients with diabetes had more diffuse coronary atherosclerosis, a greater prevalence of mild, moderate and severe stenoses and a two-fold higher occlusion rate than patients without diabetes, even after adjustment for age, gender, body mass index, hypertension, lipid parameters, smoking, family history of cardiovascular events and ischemic symptoms. Patients with "mild diabetes" had a coronary atherosclerosis pattern more similar to patients with normal fasting plasma glucose than to patients formerly defined as diabetic according to the World Health Organization criteria, except that they had a higher prevalence of <50% stenoses. CONCLUSIONS: In patients with type 2 diabetes, those with 7.0 mM/L < or = fasting plasma glucose < 7.7 mM/L have a slightly greater prevalence of mildly severe lesions that may partly explain their higher cardiovascular event rate.
Assuntos
Angiografia Coronária/normas , Doença da Artéria Coronariana/diagnóstico , Doença da Artéria Coronariana/etiologia , Diabetes Mellitus Tipo 2/complicações , Diabetes Mellitus Tipo 2/diagnóstico , Idoso , Viés , Glicemia/análise , Índice de Massa Corporal , Colesterol/sangue , HDL-Colesterol/sangue , LDL-Colesterol/sangue , Doença da Artéria Coronariana/sangue , Doença da Artéria Coronariana/classificação , Doença da Artéria Coronariana/mortalidade , Diabetes Mellitus Tipo 2/sangue , Diabetes Mellitus Tipo 2/classificação , Jejum , Feminino , Humanos , Modelos Lineares , Masculino , Pessoa de Meia-Idade , Guias de Prática Clínica como Assunto , Valor Preditivo dos Testes , Prevalência , Estudos Prospectivos , Fatores de Risco , Índice de Gravidade de Doença , Organização Mundial da SaúdeRESUMO
Radiofrequency ablation is the reference treatment of refractory nodal reentry. Cryoablation has the advantage of having more modulable effects and minimises the risk of permanent atrioventricular block (AVB). Its immediate efficacy seems comparable to that of radiofrequency ablation but the long-term results are not well known. Endocavitary cryoablation of the slow pathway was undertaken in 26 patients (18 women) with an average age of 47.7 +/- 72.8 years with re-entrant nodal tachycardia refractory to medical therapy. The primary success rate was 92% (24 out of 26). On average, 2.6 +/- 2.2 (1 to 10) cryoablations at - 70 degrees C were delivered and were preceded by 6.4 +/- 4.5 (1 to 16) cryomappings to locate the site of the slow pathway. During cryomapping, 8 episodes of AVB were observed in 6 patients (6 second or third degree), all of which were revertible on rewarming. No cases of permanent AVB were observed. An oesophageal stimulation test of inducibility was performed on the 4th day in 21 patients, 16 of which were not reinducible. During follow-up of 355 +/- 194 days, 22 of the 26 patients (85%) had no recurrence of the arrhythmia. Two of the 24 primary successes had a recurrence, in addition to the two primary failures. Two of the four recurrences occurred in a non-sustained form which was less disabilitating for the patient and the recurrences were controlled in the 4 patients by antiarrhythmic therapy. These results suggest that cryoablation may be a reliable and effective long-term treatment of re-entrant nodal tachycardias. If confirmed in larger series in terms of efficacy and safety, cryoablation could become the treatment of choice of re-entrant nodal tachycardia.
Assuntos
Nó Atrioventricular/patologia , Nó Atrioventricular/cirurgia , Ablação por Cateter/métodos , Taquicardia/cirurgia , Eletrocardiografia , Feminino , Seguimentos , Bloqueio Cardíaco , Humanos , Masculino , Pessoa de Meia-Idade , Resultado do TratamentoRESUMO
The consequences of implanting an automatic cardioverter defibrillator (ICD) on vehicle driving in France are poorly known. This retrospective study examined the behaviour at the wheel of ICD recipients who were recommended to abstain from driving for 3 to 6 months after device implantation. The study population included 98 patients (mean age = 59.5 +/- 14.8 years) followed for a mean of 24. +/- 23.9 months, who underwent ICD implant for ventricular tachycardia (65% of patients ventricular fibrillation (15%), syncope (8%), as part of a research protocol of myocardial cell transplantation 6%, or for primary prevention (5%). The underlying heart disease was ischemic in 59% of patients dilated cardiomyopathy in 11%,hypertrophic cardiomyopathy in 8%, valvular in 6%. Brugada syndrome in 4%, right ventricular arrhythmogenic cardiomyopathy in 2%, and miscellaneous disorders in 9% of patients. Five patients died without post mortem interrogation of the ICD. Only 28% of drivers remembered, and 13% observed, the recommended driving limitations. However, 45% (the oldest) claimed to drive prudently. During follow-up, 47% of patients received an ICD shock. Their mean it ventricular ejection fraction was 34 +/- 14%, versus 43 +/- 18% in patients who received no ICD therapy (p = 0.015). Syncope occurred in 16% who received ICD shocks. Shocks were delivered during driving in 6 patients, without consequent accident. Despite their non-observance of recommended driving limitations. ICD recipients suffered few traffic accidents. Legislation in France should reproduce the guidelines issued by European professional societies and enacted by the British laws.
Assuntos
Condução de Veículo , Desfibriladores Implantáveis , Acidentes de Trânsito , Idoso , Feminino , França , Humanos , Masculino , Pessoa de Meia-Idade , Política Pública , Estudos Retrospectivos , Síncope/terapia , Taquicardia Ventricular/terapia , Fibrilação Ventricular/terapiaRESUMO
Radiofrequency current is the reference energy source for endocavitary ablation of arrhythmias. It is particularly well adapted for the ablation of focal arrhythmogenic substrates such as accessory pathways or foyers of automatism. Technological advances have made the lesions larger but the extension of the indications of percutaneous ablation to more complex substrates such as atrial fibrillation have justified the evaluation of alternative energies. The production of linear transmural lesions or deeper lesions which respect the parietal myocardial architecture and endocardial structure are a challenge for these energies. The capacity of functional mapping specific to cryogenics has provided this energy source with a clinical application for ablation of high risk structures whereas other energies, despite the chronicity of their experimental evaluation, are still at the stage of preliminary clinical trials with the sophisticated catheters in special indications.
Assuntos
Arritmias Cardíacas/terapia , Ablação por Cateter/métodos , Crioterapia , Humanos , Terapia a Laser , Micro-Ondas/uso terapêutico , Terapia por UltrassomRESUMO
Thirteen open chest dogs with normal sinus node function were studied by premature stimulations with a constant relative prematurity--50% of the preceding sinus cycle length. These premature beats were induced in the lower part of the crista terminalis of the right atrium and to the roof of the left atrium. Significant linear correlations were found between the return cycle (A2A3) and the spontaneous cycle (A1A1) lengths, with a slope of +0.75 in the right atrium, +1.36 in the left atrium. The evaluation of sinus node function is disturbed by pacemaker shifts, both spontaneous and induced. Sinus node organisation may be assessed by stimulating standardised sites, by measuring intra-atrial conduction time, and by comparing A2A3 with A1A1 at constant relative prematurity during significant variations in A1A1 obtained with changes in vago-sympathetic tone.
Assuntos
Nó Sinoatrial/fisiologia , Animais , Função Atrial , Estimulação Cardíaca Artificial , Temperatura Baixa , Cães , Estimulação Elétrica , Respiração ArtificialRESUMO
STUDY OBJECTIVE: The aim of the study was to examine the electrophysiological characteristics of human atrial specimens collected during heart surgery and to investigate the effects of the class I antiarrhythmic agent flecainide on their electrical activity. DESIGN: Atrial specimens were studied using standard microelectrode techniques, with and without superfused flecainide (5 x 10(-7) M) or the transient outward current inhibitor 4-aminopyridine (0.5 mM). EXPERIMENTAL MATERIAL: Atrial fragments 0.5-1.0 cm2 were obtained at operation from 34 patients, mean age 30 years. There was no history of previous atrial arrhythmia in any patient and drug therapy was stopped 24 h before surgery. MEASUREMENTS AND MAIN RESULTS: Two types of transmembrane action potential were identified: (1) triangular shaped potentials (group A, classically found in animal models); (2) potentials with a large plateau preceded by a notch (group B). The effect of flecainide was compared on the the two types of action potential. In both, flecainide lessened the depolarisation rate. In group B, but not in group A, it increased the action potential duration at 50% and 90% repolarisation (APD50, APD90) and the effective refractory period. The notch in group B action potentials is generated by transient outward currents (Ito). Inhibition of these currents, either by increasing the pacing rate or by adding 4-aminopyridine, limited the increase in APD50, APD90, and effective refractory period generated by the presence of flecainide. CONCLUSIONS: The effects of flecainide on the atrial repolarisation process depend on the shape of the action potential. These effects are more marked in cells with a plateau, where Ito is activated.
Assuntos
Flecainida/farmacologia , Coração/efeitos dos fármacos , 4-Aminopiridina/farmacologia , Potenciais de Ação/efeitos dos fármacos , Adolescente , Adulto , Idoso , Criança , Pré-Escolar , Relação Dose-Resposta a Droga , Estimulação Elétrica , Átrios do Coração/efeitos dos fármacos , Humanos , Técnicas In Vitro , Pessoa de Meia-Idade , Fatores de TempoRESUMO
Sinoatrial conduction times, estimated by premature atrial stimulation, were compared with direct measurement of the sinoatrial conduction time in 15 isolated rabbit sinus node preparations before and after intrasinusal pacemaker shifts induced by cooling. Transmembrane potentials and surface electrograms were recorded from the sinus node and crista terminalis. Extracellular sinus node activity was recorded in five preparations. Mapping was performed at 38 degrees C and 35 degrees C to determine the site of the dominant pacemaker. The sinus cycle was significantly longer at 35 degrees C (319.4 ms vs 258.1 ms). Intracellular measured conduction time was significantly shorter (63.8 ms vs 70.4 ms) because of caudal shift of the dominant pacemaker. Estimated sinoatrial conduction time was significantly longer (110.3 ms vs 85.4 ms) owing to the depression of automaticity by the extrastimulus. Extracellular measured conduction time did not differ significantly from intracellular measured conduction time. These results suggest that intrasinusal pacemaker shift may explain inaccuracies in indirect estimations of sinoatrial conduction time by atrial pacing techniques. Extracellular recordings appear to be a better method of evaluating sinoatrial conduction times.
Assuntos
Nó Sinoatrial/fisiologia , Animais , Temperatura Baixa , Estimulação Elétrica , Átrios do Coração , Potenciais da Membrana , Coelhos , Fatores de TempoRESUMO
There is now increasing evidence that high pulse pressure, which is an indicator of large artery stiffness, is an independent risk factor for cardiovascular mortality, especially coronary mortality, in different populations. We have recently shown in a large French population that in male subjects aged 40 to 69 years, increased pulse pressure was a strong predictor of cardiovascular mortality, especially coronary mortality. In the present report, we analyzed the effect of pulse pressure in men and women of the same cohort after classifying them as normotensive (systolic blood pressure [SBP] <140 mm Hg and DBP <90 mm Hg) or hypertensive (SBP >/=160 mm Hg or DBP >/=95 mm Hg). After adjustment for age, mean blood pressure, and other risk factors, the relative risk (95% confidence limits) for cardiovascular mortality for an increase of 10 mm Hg of pulse pressure was 1.20 (1.01 to 1.44) in normotensives and 1.09 (1.03 to 1.14) in hypertensives. Cardiovascular and coronary death rates were similar in the group of normotensive men with a pulse pressure >50 mm Hg and in the group of hypertensive men with a pulse pressure <45 mm Hg. No association between cardiovascular mortality and pulse pressure was observed in either normotensive or hypertensive women (0.85 [0.60 to 1.21] and 1.0 [0. 91 to 1.11], respectively). Low mortality rates could explain this observation in normotensive but not in hypertensive women, in whom cardiovascular mortality rates were relatively high. Because a high pulse pressure in men is an independent predictor of cardiovascular mortality in both hypertensives and in those considered as having normal blood pressure, this parameter could aid in evaluating cardiovascular risk.
Assuntos
Pressão Sanguínea , Doença das Coronárias/mortalidade , Hipertensão/fisiopatologia , Adulto , Idoso , Causas de Morte , Colesterol/sangue , Estudos de Coortes , Doença das Coronárias/etiologia , Feminino , França/epidemiologia , Humanos , Hipertensão/complicações , Masculino , Pessoa de Meia-Idade , Fatores de RiscoRESUMO
Studies on the prognostic significance of blood pressure on cardiovascular disease have essentially investigated the levels of diastolic or systolic blood pressure. However, blood pressure may also be divided into two other components: steady (mean arterial pressure) and pulsatile (pulse arterial pressure). The relations of these two components with cardiovascular risk factors and cardiovascular mortality were investigated in 18,336 men and 9,351 women aged 40-69 years, who were followed up for a mean period of 9.5 years. However, the interpretation of the relations is complicated by the strong correlation existing between these two components. A principal component analysis was performed to obtain two independent parameters: a steady and a pulsatile component index, strongly correlated with mean and pulse arterial pressure, respectively. In the cross-sectional analysis, relations were stronger with the steady component index than with the pulsatile component index; an association was found between left ventricular hypertrophy and the pulsatile component index in both sexes. The survival analysis was not performed in women under 55 as only 11 cardiovascular deaths occurred in this group. The steady component index was a strong prognostic factor of all types of cardiovascular death in both sexes. In women, the pulsatile component index was positively correlated to death from coronary artery disease and inversely correlated to stroke. In conclusion, the steady component of blood pressure is a strong risk factor for cardiovascular death in both sexes; the pulsatile component could be a risk factor independent of the steady component in women older than 55 years.
Assuntos
Pressão Sanguínea , Doenças Cardiovasculares/mortalidade , Pulso Arterial , Adulto , Fatores Etários , Idoso , Cardiomegalia/mortalidade , Cardiomegalia/fisiopatologia , Doenças Cardiovasculares/fisiopatologia , Estudos Transversais , Feminino , França , Humanos , Masculino , Pessoa de Meia-Idade , Prognóstico , Estudos Prospectivos , Fatores de Risco , Fatores SexuaisRESUMO
-The aim of the present study was to assess the effects of high heart rate on mortality in different subgroups in a French population according to age, gender, and blood pressure levels. We studied 19 386 subjects (12 123 men, 7263 women), aged 40 to 69 years, who had a routine health examination at the Centre d'Investigations Préventives et Cliniques (IPC) between 1974 and 1977. Heart rate (HR) measured by ECG was classified into 4 groups: HR1, <60; HR2, 60 to 80; HR3, 81 to 100; and HR4, >100 bpm. Mortality data were recorded for the period of 1974 through 1994. In both sexes, HR was a significant predictor of noncardiovascular mortality. In men, the relative risk (95% confidence interval) for cardiovascular death after adjustment for age and other risk factors in the HR2, HR3, and HR4 groups was 1.35 (1.01 to 1.80), 1.44 (1.04 to 2.00), and 2.18 (1.37 to 3.47), respectively, when compared with HR1. In women, HR did not influence cardiovascular mortality. The association of HR with cardiovascular mortality in men was (1) related to a strong association with coronary but not cerebrovascular mortality, (2) independent of age and hypertension, and (3) influenced by the level of pulse pressure; in patients with high pulse pressure (>65 mm Hg), accelerated HR was not associated with increased cardiovascular mortality. In conclusion, in a large French population, accelerated resting HR represents an independent predictor of noncardiovascular mortality in both genders, and of cardiovascular mortality in men, independent of age and the presence of hypertension. Further investigations are needed to explain the complex interactions between HR, pulse pressure, and cardiovascular complications.
Assuntos
Pressão Sanguínea , Frequência Cardíaca , Mortalidade , Adulto , Fatores Etários , Idoso , Doenças Cardiovasculares/mortalidade , Transtornos Cerebrovasculares/mortalidade , Colesterol/sangue , Intervalos de Confiança , Doença das Coronárias/mortalidade , Interpretação Estatística de Dados , Feminino , Seguimentos , França , Humanos , Hipertensão/mortalidade , Masculino , Pessoa de Meia-Idade , Esforço Físico , Pulso Arterial , Risco , Fatores de Risco , Fatores Sexuais , Fumar/efeitos adversos , Fatores de TempoRESUMO
Studies on the usefulness of blood pressure as a prognostic factor in cardiovascular disease have more often involved investigations of the levels of diastolic or systolic blood pressure. However, blood pressure may be divided into two other components: steady (mean pressure) and pulsatile (pulse pressure). In this study, the relationship of pulse pressure to cardiovascular mortality was investigated in 19 083 men 40 to 69 years old who were undergoing a routine systematic health examination and were being followed up after a mean period of 19.5 years. Subjects were divided into four groups according to age (40 to 54 and 55 to 69 years) and mean arterial pressure (<107 and > or =107 mm Hg). Each group was further divided into four subgroups according to the pulse pressure level. A wide pulse pressure (evaluated according to the quartile group or as a continuous quantitative variable) was an independent and significant predictor of all-cause, total cardiovascular, and, especially, coronary mortality in all age and mean pressure groups. No significant association between pulse pressure and cerebrovascular mortality was observed. In conclusion, in a large population of men with a relatively low cardiovascular risk, a wide pulse pressure is a significant independent predictor of all-cause, cardiovascular, and, especially, coronary mortality.
Assuntos
Pressão Sanguínea , Doenças Cardiovasculares/mortalidade , Transtornos Cerebrovasculares/mortalidade , Doença das Coronárias/mortalidade , Adulto , Fatores Etários , Idoso , Causas de Morte , Estudos de Coortes , Seguimentos , França/epidemiologia , Humanos , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Decúbito DorsalRESUMO
A recent prospective study has suggested that increased plasma viscosity may be associated with higher risk of coronary heart disease. A longitudinal approach was used to investigate associations between plasma viscosity and conventional risk factors in an apparently healthy French population aged 45-56 years (637 men and 431 women) over a 2-year follow-up period. In univariate analysis, change in plasma viscosity was significantly related to changes in smoking status, systolic and diastolic blood pressure, gamma glutamyl transferase (gamma GT), body mass index and triglycerides only in men, and to changes in total cholesterol, low-density lipoprotein (LDL) cholesterol and apolipoprotein (apo) B in both sexes. Change in plasma viscosity was also significantly associated with changes in fibrinogen and hemoglobin levels in both sexes. No association was found with age, high-density lipoprotein (HDL) cholesterol or apo A1 in both sexes, or with changes in smoking and menopausal status in women. In multiple stepwise regression analysis, independent determinants of change in plasma viscosity were changes in smoking status, systolic blood pressure, gamma GT, total cholesterol, fibrinogen and hemoglobin in men, and changes in fibrinogen and apo B in women. These results strengthen the hypothesis that increased plasma viscosity may be one of the mechanisms linking conventional risk factors to the risk of cardiovascular disease and suggest that its decrease may be obtained by appropriate life-style changes.