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1.
Ann Cardiol Angeiol (Paris) ; 68(5): 293-299, 2019 Nov.
Artigo em Francês | MEDLINE | ID: mdl-31542198

RESUMO

PURPOSE: The percutaneous coronary interventions use large doses of ionizing radiation, particularly when treating complex lesions. The incidence of radio-induced skin lesions is poorly known. Our goal was to evaluate the frequency of occurrence of such lesions, as well as the factors that may contribute to a high radiation dose. The recommended DAP (dose-area product) cutoff for skin monitoring after percutaneous coronary interventions is 500Gy cm2. PATIENTS AND METHOD: We prospectively studied the incidence of acute (after 5-7 days) and subacute (after 7 days to 6 months) skin lesions following angioplasty with a dose-area product (DAP) ≥200Gy cm2 in patients who underwent coronary angioplasty in our center in 2013. RESULTS: Nine hundred and thirty three consecutive procedures were analyzed, of which 102 with a DAP ≥200Gy cm2. Three patients presented an acute lesion. Two of these three patients also had subacute lesions. Another patient presented only a subacute lesion. 4.82% (95% CI: [0-10]) of the patients with a DAP ≥200Gy cm2 developed radiodermitis lesions, or 0.47% (95% CI: [0-0.9]) of all the patients who underwent angioplasty. The Body Mass Index and the elective (as opposed to energy) procedures were independently associated with a procedure with a DAP ≥200Gy cm2. CONCLUSION: Radiodermatitis lesions occur for 4.82% of patients benefiting from procedures with a DAP ≥200Gy cm2. We suggest the establishment of a DAP threshold for dermal monitoring of patients of 200Gy cm2 per procedure instead of 500Gy cm2.


Assuntos
Intervenção Coronária Percutânea , Radiodermite/epidemiologia , Radiodermite/etiologia , Radiografia Intervencionista/efeitos adversos , Idoso , Angioplastia Coronária com Balão/efeitos adversos , Feminino , Humanos , Incidência , Masculino , Pessoa de Meia-Idade , Intervenção Coronária Percutânea/métodos , Estudos Prospectivos
2.
Ann Cardiol Angeiol (Paris) ; 66(6): 380-384, 2017 Dec.
Artigo em Francês | MEDLINE | ID: mdl-29096903

RESUMO

A large thrombus burden is not uncommon in primary percutaneous coronary intervention, and is associated with more frequent complications. The role of intracoronary thrombolysis and glycoprotein IIb/IIIa inhibitors in the management of a large thrombus burden is discussed. The use of thromboaspiration must follow a particular logic and used with rigorous manipulations; the capacities of the protective filters are often exceeded. Stents dedicated to thrombus management can be used. Interest and limits of these stents are developed. Direct stenting should be encouraged, and delayed stenting probably considered for the most important thrombotic burden despite "negative" results in studies.


Assuntos
Trombose Coronária/terapia , Intervenção Coronária Percutânea/efeitos adversos , Inibidores da Agregação Plaquetária/uso terapêutico , Stents , Trombectomia , Angioplastia Coronária com Balão/métodos , Humanos , Metanálise como Assunto , Complexo Glicoproteico GPIIb-IIIa de Plaquetas/antagonistas & inibidores , Trombectomia/métodos , Terapia Trombolítica/métodos , Resultado do Tratamento
3.
Eur J Heart Fail ; 4(5): 617-25, 2002 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-12413506

RESUMO

AIMS: With the complex demodulation (CDM) method, we assessed the instantaneous amplitude and frequency of cardiovascular (CV) and respiratory oscillations, and the instant phase (IP) between the CV and respiratory signals using respiration as a periodic forced stimulation. We hypothesised a possible lack of synchronisation between CV and respiratory signals under regular breathing at different frequencies. METHODS: RR interval (ECG), blood pressure (SBP/DBP, Finapress), respiration (Respitrace) were monitored during two random-order periods of voluntary paced-breathing (0.15 Hz/0.25 Hz) in 10 moderate CHF patients and 10 age-matched controls. The CDM method provides the amplitude and frequency of a particular spectral component as a function of time in both LF and HF bands. IP between CV and respiratory oscillations was assessed using the real modulating breathing rate. RESULTS: (i) Continuous phase variations between CV oscillations and the respiratory signal were evidenced in CHF patients, the slower the breathing rate, the greater the phase variation (RR/Resp; 0.25 Hz, 23+/-17 degrees; 0.15 Hz, 46+/-57 degrees, P<0.01; RR/Resp at 0.15 Hz 6+/-3 vs. 46+/-57 P<0.01 controls vs. CHF). Phase was constant in controls. (ii) In patients, the instant amplitude of the cardiovascular oscillations in the high frequency domain is more markedly altered when the breathing rate was slowed down as compared to controls. CONCLUSION: The lack of synchronisation between physiological signals during voluntary breathing in CHF patients highlights a central uncoupling between CV and respiratory neuronal activities.


Assuntos
Sistema Cardiovascular/fisiopatologia , Insuficiência Cardíaca/fisiopatologia , Sistema Respiratório/fisiopatologia , Adulto , Pressão Sanguínea/fisiologia , Doença Crônica , Eletrocardiografia , Feminino , Insuficiência Cardíaca/terapia , Ventilação de Alta Frequência , Humanos , Masculino , Pessoa de Meia-Idade , Variações Dependentes do Observador , Respiração , Sístole/fisiologia , Fatores de Tempo
4.
Presse Med ; 31(31): 1454-7, 2002 Sep 28.
Artigo em Francês | MEDLINE | ID: mdl-12395736

RESUMO

INTRODUCTION: The spontaneous prognosis of pulmonary embolism associated with mobile intra-cardiac thrombus is most severe, and the choice of a therapeutic strategy is often difficult. OBSERVATION: The treatment of a patient with intravenous fibrinolytics for massive pulmonary embolism and right atrium thrombus was complicated by his early death. We attributed his death to the migration of the intra-cardiac thrombus. Indeed, the cardiac ultrasound, performed when the patient's hemodynamic state had worsened, revealed the complete disappearance of the thrombus too early to correspond to its complete lysis (30th minute of fibrinolysis). COMMENTS: In this pathology, several therapeutic approaches are possible. Surgical removal of the embolus has been validated, but cannot be proposed to all patients since it is a high-risk intervention. Fibrinolysis is generally efficient but exposes the patient to the risk of migration of the intra-cavity thrombus with occasionally deleterious evolution (as in our patient). Heparin treatment alone has been proposed as an alternative when the other two techniques are contraindicated. These techniques currently require assessment in a randomized study, in order to define the appropriate therapeutic strategy.


Assuntos
Átrios do Coração , Embolia Pulmonar/tratamento farmacológico , Terapia Trombolítica/efeitos adversos , Trombose/tratamento farmacológico , Adenocarcinoma/patologia , Idoso , Evolução Fatal , Átrios do Coração/patologia , Humanos , Pulmão/patologia , Neoplasias Pulmonares/patologia , Metástase Linfática , Masculino , Artéria Pulmonar/patologia , Embolia Pulmonar/diagnóstico , Embolia Pulmonar/patologia , Fatores de Risco , Trombose/diagnóstico , Trombose/patologia , Trombose Venosa/diagnóstico , Trombose Venosa/tratamento farmacológico , Trombose Venosa/patologia
5.
Arch Mal Coeur Vaiss ; 95 Spec No 5: 15-24, 2002 Apr.
Artigo em Francês | MEDLINE | ID: mdl-12055752

RESUMO

Preventive treatments for atrial fibrillation by stimulation have been developed for several years now, mainly due to the relative failure of anti-arrhythmic treatments. They are based on the hypothetical effects of stimulation by controlling cardiac frequency, abolishing bradycardia-dependent extrasystoles, by the inhibition of atrial automatic foci with "overdrive", and by the modification of intra- or inter-atrial conduction delays as well as by remodelling the arrhythmogenic substrate. It is clear that an undeniable effect exists for the prevention of atrial fibrillation, even for the risk of cerebral vascular accident, by physiological stimulation (DDD/DDDR) compared to pure ventricular stimulation (VVI/VVIR) in a heterogenous global population of stimulated patients. For the moment, there is not sufficient proof of a positive effect for the emerging sites of cardiac stimulation, either atrial mono-site or double site in the populations at high risk of atrial fibrillation, with or without associated bradycardia. Some new prevention algorithms by "overdrive" are under development but for the moment only a few preliminary studies seem to show a slight benefit. It is clear that at present stimulation should be reserved only for cases of atrial fibrillation associated with a classic indication for implantation. In these patients it is recommended to position the probes in an optimal manner in order to counteract conduction disorders, choosing an adapted double chamber stimulator with prevention algorithms. That said, the patient should be clearly warned that the long term success rate is no more than 50%.


Assuntos
Fibrilação Atrial/terapia , Terapia por Estimulação Elétrica , Algoritmos , Fibrilação Atrial/complicações , Fibrilação Atrial/fisiopatologia , Bradicardia/prevenção & controle , Humanos , Prognóstico , Fatores de Risco , Resultado do Tratamento
6.
Cerebrovasc Dis ; 12(4): 318-24, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11721102

RESUMO

Patent foramen ovale is frequently associated with embolic cerebrovascular accidents. The diagnosis of patent foramen ovale is easier since the advent of transesophageal echocardiography. However, this method is semi-invasive and is not readily available in all units. Contrast transcranial Doppler ultrasound enables the detection of the passage of a contrast material injected into a peripheral vein to the cerebral circulation across an orifice which is most often a patent foramen ovale. Contrast transcranial Doppler ultrasound may facilitate, with a high sensitivity and specificity, the diagnosis of a patent foramen ovale when a transesophageal echo is not possible. However, transesophageal echocardiography remains the preferred test especially in the young since other potentially embolic sources, such as a thrombus in the left atrium, may be demonstrable.


Assuntos
Ecocardiografia , Comunicação Interatrial/diagnóstico por imagem , Acidente Vascular Cerebral/complicações , Ultrassonografia Doppler Transcraniana , Humanos
7.
Auton Neurosci ; 90(1-2): 24-8, 2001 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-11485287

RESUMO

Heart rate variability (HRV) can be assessed through a time frequency analysis, the smoothed pseudo Wigner-Ville transformation (SPWVT). Such an analysis has allowed the calculation of ICF, a frequential index, extremely sensitive to the modulation of the sympatho-vagal balance. The use of ICF has been applied in the present study to two clinical situations for which a role of this balance was probable, brain death and atrial fibrillation (AF). The use of the time frequency analysis immediately identified the timing of brain death. No difference could be found in the analysis of the 30 min preceding an atrial fibrillation episode. It is suggested that a time frequency analysis should be used in clinical situations in which transitory fluctuations of the sympatho-vagal balance are expected and crucial to the well being of the patients.


Assuntos
Fibrilação Atrial/fisiopatologia , Morte Encefálica/fisiopatologia , Frequência Cardíaca/fisiologia , Sistema Nervoso Simpático/fisiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Nervo Vago/fisiologia
8.
J Cardiovasc Electrophysiol ; 12(6): 639-44, 2001 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-11405396

RESUMO

INTRODUCTION: The aim of this study was to evaluate simultaneously cardiac autonomic activity, through heart rate variability (HRV) analysis, and cardiac inotropic changes during head-up tilt (HUT) in patients with recurrent vasovagal syncope. METHODS AND RESULTS: Twelve subjects implanted with a permanent dual-chamber pacemaker for recurrent vasovagal syncope characterized by marked bradycardia were studied. The tip of the right ventricular electrode was equipped with a sensor that measured peak endocardial acceleration (PEA) as an index of myocardial contractility. RR interval and PEA signals were acquired simultaneously and processed in the time and frequency (low frequencies [LF] and high frequencies [HF] of RR signal) domain during early HUT (T1), late HUT, or before syncope (T2). In the six subjects with positive HUT: (1) Abnormal heart rate oscillations were evidenced at T1 and discriminated this group from the negative group (LF/HF decreased by 46% from supine to T1, but increased by 55% in the negative group; P < 0.01 positive vs negative HUT). (2) Gradual diminution of the HF component was associated with an increase in PEA index during HUT with a correlation between PEA/RR interval (R = -0.8, P < 0.001), PEA/HF components (R = -0.6, P < 0.05). (3) Sympathetic stimulation responsible for changes in both HRV and PEA parameters occurred immediately before the faint (LF/LF+HF: 0.6 +/- 0.2 to 0.8 +/- 0.09; P < 0.05 T2 vs T1; PEA: 0.62 +/- 0.10G to 0.83 +/- 0.22G; P < 0.01 T2 vs T1). CONCLUSION: Our findings showed that a homogeneous subgroup of patients with recurrent vasovagal syncope and positive HUT exhibited abnormal cardiac autonomic and inotropic responses to an orthostatic stimulus. Continuous changes over time of HRV and PEA parameters highlight the dynamic behavior of the mechanisms leading to syncope.


Assuntos
Frequência Cardíaca/fisiologia , Contração Miocárdica/fisiologia , Síncope Vasovagal/fisiopatologia , Adulto , Eletrocardiografia , Feminino , Humanos , Masculino , Postura/fisiologia , Processamento de Sinais Assistido por Computador , Síncope/fisiopatologia
9.
J Hum Hypertens ; 15(3): 209-11, 2001 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-11317207

RESUMO

A 62-year-old man had an acute episode of hypertension 72 h after fine needle aspiration biopsy of an intra- hepatic nodule. The patient had been operated 3 years previously for a right adrenal phaeochromocytoma with no evidence of metastases at that time. Thus, a relapse of the tumour was postulated and confirmed by raised levels of urinary metanephrines. The extent of the metastases precluded surgical intervention and thus localised embolisation was proposed and permitted a clinical stabilisation over 8 months. This case indicates the necessity of long-term post-operative follow-up of phaeochromocytoma as well as the dangers of fine needle aspiration biopsy of metastases from this kind of tumour. Treatment of malignant phaeochromocytoma is difficult and embolisation was a useful therapeutic alternative in this case where the metastases were well defined.


Assuntos
Neoplasias das Glândulas Suprarrenais/patologia , Glândulas Suprarrenais/patologia , Hipertensão/fisiopatologia , Feocromocitoma/patologia , Neoplasias das Glândulas Suprarrenais/terapia , Biópsia por Agulha/efeitos adversos , Embolização Terapêutica , Humanos , Hipertensão/patologia , Masculino , Pessoa de Meia-Idade , Recidiva Local de Neoplasia/patologia , Recidiva Local de Neoplasia/terapia , Feocromocitoma/terapia
10.
Eur J Heart Fail ; 3(2): 189-95, 2001 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-11246056

RESUMO

BACKGROUND: We assessed the behavior of the baroreflex (BR) gain in chronic heart failure (CHF) patients using the spectral analysis method during application of a forcing stimulus, i.e. respiration. METHODS: Simultaneous RR interval and arterial pressure fluctuation recordings were obtained during two random-order periods of voluntary paced-breathing (0.15 Hz and 0.25 Hz) in seven patients with moderate CHF (NYHA class II/III; EF, 30+/-9%; peak VO(2), 18+/-5 ml kg(-1) min(-1)) and six age-matched controls. BR gain was assessed in the time (sequential method) and frequency (cross-spectral gain in the low and high frequency) domains. RESULTS: Slower breathing was associated with a BR gain decrease in CHF patients whereas a BR gain increase was evidenced in controls (BR gain: 6+/-5 ms mmHg(-1) at 0.25 Hz vs. 4+/-3 ms mmHg(-1) at 0.15 Hz, P<0.05 in CHF; BR gain: 12+/-7 ms mmHg(-1) at 0.25 Hz vs. 15+/-7 ms mmHg(-1) at 0.15 Hz, P<0.05 in controls). CONCLUSIONS: Voluntary breathing, which involves cortical centers in the brain, had major effects on cardiovascular system controller gain in CHF patients, indicating an impairment of the central neural regulation of the autonomic outflow.


Assuntos
Insuficiência Cardíaca/fisiopatologia , Pressorreceptores/fisiopatologia , Ventilação Pulmonar/fisiologia , Adulto , Sistema Nervoso Autônomo/fisiopatologia , Biorretroalimentação Psicológica/fisiologia , Pressão Sanguínea/fisiologia , Doença Crônica , Feminino , Insuficiência Cardíaca/diagnóstico , Humanos , Masculino , Pessoa de Meia-Idade
11.
Eur Heart J ; 21(22): 1872-6, 2000 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-11052860

RESUMO

AIMS: Although dilated cardiomyopathy is the most frequent form of cardiomyopathy, its aetiology is still poorly understood. In about 20-30% of cases the disease is familial with a large predominance of autosomal dominant transmission. Ten different chromosomal loci have been described for autosomal dominant forms of dilated cardiomyopathy. Only two genes have been associated with pure forms (without myopathy and/or conduction disorders) of the disease, the cardiac actin and the desmin genes. Our aim was to determine the proportion of dilated cardiomyopathy affected individuals carrying a mutation in one of these two genes. METHODS AND RESULTS: We performed (1) a systematic polymerase chain reaction-SSCP-sequencing screening of the coding sequences of cardiac actin on DNA samples from 43 probands of dilated cardiomyopathy families and 43 sporadic cases; (2) a systematic polymerase chain reaction-SSCP-sequencing screening of the coding sequences of desmin combined with a search for the described missense mutation (Ile451Met) by restriction fragment length polymorphism analysis on DNA samples from 41 probands of dilated cardiomyopathy families and 22 sporadic cases. CONCLUSION: None of the patients presents a mutation in any of these two genes. Consequently, the proportion of European dilated cardiomyopathy affected individuals bearing a mutation in (1) the cardiac actin gene is less than 1.2%, (2) the desmin gene is less than 1.6%.


Assuntos
Actinas/genética , Actinas/metabolismo , Cardiomiopatia Dilatada/genética , Desmina/genética , Mutação , Miocárdio/metabolismo , Sequência de Bases/genética , Cardiomiopatia Dilatada/metabolismo , Europa (Continente) , Frequência do Gene , Testes Genéticos , Humanos , Polimorfismo Conformacional de Fita Simples
12.
Hypertension ; 36(3): 350-4, 2000 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-10988263

RESUMO

We quantified the repolarization time (so-called QT interval) in a rat, an animal species that does not show a well-characterized T wave on surface ECG. We used spontaneously hypertensive rats (SHR) and converting enzyme inhibition to demonstrate a reversible increase in QT interval in pressure-overloaded hearts in the absence of ischemia. An implanted telemetry system recording ECG data in freely moving rats was used to automatically calculate the RR interval. The QT duration was manually determined by use of a calibrated gauge, and a time-frequency domain analysis was used to evaluate heart rate variability. Left ventricular mass was sequentially assessed by echocardiography. Before treatment, 12-month-old SHR had higher left ventricular mass, QT and RR intervals, and unchanged heart rate variability compared with age-matched Wistar rats. A 2-month converting enzyme inhibition treatment with trandolapril reduces systolic blood pressure, left ventricular mass, and QT interval. The RR interval and heart rate variability remains unchanged. There is a positive correlation between the QT interval and left ventricular mass. The SHR is suitable for longitudinal studies on the QT interval. Thus, the detection of the QT interval reflects the phenotypic changes that occur during mechanical overload and, on the basis of these criteria, allows an in vivo determination of the adaptational process.


Assuntos
Inibidores da Enzima Conversora de Angiotensina/farmacologia , Modelos Animais de Doenças , Eletrocardiografia Ambulatorial/métodos , Eletrocardiografia/efeitos dos fármacos , Frequência Cardíaca/efeitos dos fármacos , Hipertensão/fisiopatologia , Hipertrofia Ventricular Esquerda/fisiopatologia , Fatores Etários , Animais , Ecocardiografia , Hipertensão/tratamento farmacológico , Indóis/farmacologia , Variações Dependentes do Observador , Ratos , Ratos Endogâmicos SHR , Ratos Wistar , Análise de Regressão , Reprodutibilidade dos Testes , Especificidade da Espécie
13.
Presse Med ; 29(1): 4-10, 2000 Jan 15.
Artigo em Francês | MEDLINE | ID: mdl-10682045

RESUMO

OBJECTIVE: The efficiency of venous thromboembolism prophylaxis with low molecular weight heparins (LMWH) has not been established in non surgical patients, so their official preventive use has been limited in France since 1995 to surgery. However, a survey conducted in 5 university hospitals in non surgical patients showed that 21-29% of patients still received a LMWH prescription. It seemed necessary to define the medical conditions for which the practical use of these heparins would be justified. We contacted external experts to obtain a consensus by using the Delphi method. METHODS: The Delphi method, created by the "Rand Corporation" in the USA and used in medicine since the nineteen seventies, is based on a light logistic, with questionnaires been sent by mail with a feed-back report A total of 48 experts were chosen by local staff teams in the 5 hospitals. For the 3 rounds, from March to October 1998, questions were devised by a multicentred staff team. RESULTS: Among the 48 experts contacted, 32 completed the 3 questionnaires, 7 of them did for 2, and 43 did for at least one questionnaire. The experts first defined a list of 12 risk or high risk situations and 11 aggravating factors. For any high risk situation, prescription is justified. For other cases, 2 risk situations are required, or one risk situation with at least 2 aggravating factors, to justify a prescription. If no risk situation is present, prescription is, according to experts, usually not justified. CONCLUSION: The maximal agreement defines the situations in which one use of low molecular weight heparins is proposed to prevent deep venous thrombosis in non surgical inpatients, in most current hospital situations and for more than 24 hours of hospitalization. Clinical trials are needed, to validate their effectiveness and define the optimal dose in these indications. To date, epidemiological studies should be conducted to evaluate the experts proposals by estimating risk factors for deep venous thrombosis.


Assuntos
Heparina de Baixo Peso Molecular/administração & dosagem , Hospitalização , Tromboembolia/prevenção & controle , Método Duplo-Cego , Heparina de Baixo Peso Molecular/farmacologia , Departamentos Hospitalares , Humanos
14.
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
15.
J Cardiovasc Pharmacol ; 32(4): 601-7, 1998 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-9781928

RESUMO

Heart rate (HR) and heart rate variability (HRV) are risk markers in cardiac disease. HRV is also an index of the sympathovagal modulation of heart rate. Their relations have been rarely analyzed. We aimed to study such relations in normal adult conscious rats by using a novel bradycardic agent, a sinus node inhibitor, S-16257. Placebo-drug crossover designs were used while monitoring HR with telemetry and analyzing HRV in both time and frequency domains. S-16257 (2 mg/kg; n = 10) decreased HR by 29% and markedly increased HRV in parallel. By using various combinations of S-16257, atropine (2 mg/kg), and propranolol (4 mg/kg), a positive relation was shown between RR interval and various indexes of HRV: the slower the HR, the greater the HRV. Nevertheless, there is one exception to this correlation. When S-16257 was associated with both atropine and propranolol, the deep bradycardia was accompanied by a reduction of HRV, which indicates that the physiologic negative correlation between HR and HRV is not an intrinsic property of the pacemaker but is highly dependent on the two components of the autonomic system.


Assuntos
Benzazepinas/farmacologia , Cardiotônicos/farmacologia , Frequência Cardíaca/efeitos dos fármacos , Animais , Antiarrítmicos/farmacologia , Atropina/farmacologia , Benzazepinas/administração & dosagem , Cardiotônicos/administração & dosagem , Interações Medicamentosas , Frequência Cardíaca/fisiologia , Injeções Intraperitoneais , Ivabradina , Masculino , Propranolol/farmacologia , Ratos , Ratos Wistar
16.
Cardiovasc Drugs Ther ; 10(6): 677-85, 1997 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-9110110

RESUMO

Heart rate varies with respiration, blood pressure, emotion, etc., and heart rate variability (HRV) is presently one of the best indices to predict fatal issues in cardiac failure and after myocardial infarction. HRV depends on various reflexes. In addition, parallel studies of HRV and the myocardial adrenergic and muscarinic transduction system in experimental models of cardiac hypertrophy (CH) have suggested that the myocardial phenotype at the sinus-node level may also play a role. A transgenic strain of mice with atrial overexpression of the beta 1-adrenergic receptors was generated with attenuated HRV, which demonstrates that the phenotype itself is a determinant of HRV. HRV is explored by noninvasive techniques, including simple determination of the standard error of the mean, time-domain analysis, and Fourier transformation. We recently developed a time and frequency domain method of analysis, the smoothed pseudo-Wigner-Ville transformation, which allows better exploration of nonstationarity. Nonlinear methods have also been applied due to the extreme complexity of the biological determinants, and have provided evidence of a chaotic attractor in certain conditions. It is proposed that in steady state a very simple process, which is not completely deterministic, could better explain intermit interval regulations than chaotic behavior. In contrast, under extreme circumstances the regulation proceeds using chaotic behavior. Arrhythmias and HRV can be quantitated in 16-month-old unanesthetized spontaneously hypertensive rats (SHR). Ventricular premature beats are more frequent in SHR than in age-matched controls; they disappear after converting enzyme inhibition (CEI) relative to the reduction of both cardiac hypertrophy and ventricular fibrosis. HRV is attenuated in SHR, as it is in compensatory CH in humans. When CH is prevented, HRV returns to normal. CEI is therefore antiarrhythmic. Another pharmacological application of this concept concerns the bradycardic agents that may improve HRV.


Assuntos
Relógios Biológicos/efeitos dos fármacos , Baixo Débito Cardíaco/tratamento farmacológico , Frequência Cardíaca/efeitos dos fármacos , Infarto do Miocárdio/tratamento farmacológico , Animais , Interpretação Estatística de Dados , Análise de Fourier , Humanos , Fenótipo , Prognóstico
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