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Cardiac afferents and neurohormonal activation in congestive heart failure

MEDICAL HYPOTHESES 2000年第2期54卷 242-253页

作者： Davila, DF Donis, JH Bellabarba, G Torres, A Casado, J de Davila, CM Univ Los Andes Ctr Invest Cardiovasc Dept Pediat Merida Venezuela

Cardiac chambers have afferent connections to the brainstem and to the spinal cord, Vagal afferents mediate depressor responses and become activated by volume expansion, increased myocardial contractility and atrial natriuretic factor. Sympathetic afferents, on the contrary, are activated by metabolic mediators, myocardial ischemia and cardiac enlargement. These opposite behaviors may lead to activation or suppression of the sympathetic nervous system and of the renin-angiotensin-aldosterone system. As cardiac diseases progress, the heart dilates, plasma norepinephrine increases, atrial natriuretic factor is released and the renin-angiotensin-aldosterone system is suppressed to maintain water and sodium excretion. This dissociation of the neurohormonal profile of cardiac patients, may be explained by coactivation of sympathetic afferents, by cardiac dilatation, and of vagal afferents by atrial natriuretic factor. in more advanced stages, atrial natriuretic factor suppression of the renin-angiotensin-aldosterone system is overridden by overt sympathetic activation and sodium and water retention ensues. Digitalis, angiotensin-converting enzyme inhibitors and beta-blockers selectively decrease cardiac adrenergic drive. A common mechanism of action, to all three groups of drugs, would be attenuation of sympathetic afferents and partial normalization of vagal afferents. Consequently, heart size and cardiac afferents emerge as the key factors to understand the pathophysiology and treatment of the syndrome of congestive heart failure. (C) 2000 Harcourt Publishers Ltd.

关键词：传入通路/生理学传入通路/病理生理学心钠素/生理学脑干/生理学脑干/病理生理学模型心血管模型神经学心肌收缩去甲肾上腺素/生理学肾素-血管紧张素系统脊髓/生理学脊髓/病理生理学迷走神经/生理学迷走神经/病理生理学动物人类

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Autonomic nervous system dysfunction in adolescents with postural orthostatic tachycardia syndrome and chronic fatigue syndrome is characterized by attenuated vagal baroreflex and potentiated sympathetic vasomotion

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PEDIATRIC RESEARCH 2000年第2期48卷 218-226页

作者： Stewart, JM New York Med Coll Ctr Pediat Hypotens Dept Pediat Valhalla NY 10595 USA

The objective was to determine the nature of autonomic and vasomotor changes in adolescent patients with orthostatic tachycardia associated with the chronic fatigue syndrome (CFS) and the postural orthostatic tachycardia syndrome (POTS). Continuous electrocardiography and arterial tonometry was used to investigate the heart rate and blood pressure responses before and 3-5 min after head-up tilt in 22 adolescents with POTS and 14 adolescents with CFS, compared with control subjects comprising 10 healthy adolescents and 20 patients with simple faint. Heart rate and blood pressure variability, determined baroreceptor function using transfer function analysis, and measured cardiac vagal and adrenergic autonomic responses were calculated using timed breathing and the quantitative Valsalva maneuver. Two of 10 healthy controls and 14 of 20 simple faint patients experienced vasovagal syncope during head-up tilt. By design, all CFS and POTS patients experienced orthostatic tachycardia, often associated with hypotension. R-R interval and heart rate variability were decreased in CFS and POTS patients compared with control subjects and remained decreased with head-up tilt. Low-frequency (0.05-0.15 Hz) blood pressure variability reflecting vasomotion was increased in CFS and POTS patients compared with control subjects and increased further with head-up tilt. This was associated with depressed baroreflex transfer indicating baroreceptor attenuation through defective vagal efferent response. Only the sympathetic response remained. Heart rate variability declined progressively from normal healthy control subjects through syncope to POTS to CFS patients, Timed breathing and Valsalva maneuver were most often normal in CFS and POTS patients, although abnormalities in select individuals were found. Heart rate and blood pressure regulation in POTS and CFS patients are similar and indicate attenuated efferent vagal baroreflex associated with increased vasomotor tone. Loss of beat-to-bea

关键词：自主神经系统疾病/病因学压力感受器反射/生理学血压疲劳综合征慢性/病理生理学心率/生理学体位参考值呼吸力学交感神经系统/病理生理学晕厥/病理生理学心动过速/病理生理学倾斜台试验迷走神经/病理生理学 Valsalva动作青少年人类

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Parasympathetic dysautonomia precedes left ventricular systolic dysfunction in Chagas disease

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AMERICAN HEART JOURNAL 2001年第2期141卷 260-265页

作者： Ribeiro, ALP Moraes, RS Ribeiro, JP Ferlin, EL Torres, RM Oliveira, E Rocha, MOC Univ Fed Minas Gerais Hosp Clin Belo Horizonte MG Brazil Univ Fed Minas Gerais Sch Med Belo Horizonte MG Brazil Hosp Clin Porto Alegre Div Cardiol Porto Alegre RS Brazil Hosp Clin Porto Alegre Biomed Engn Div Porto Alegre RS Brazil Univ Fed Rio Grande do Sul Sch Med Dept Med Porto Alegre RS Brazil

Background Parasympathetic dysautonomia is an established feature of advanced Chagas cardiomyopathy. How ever, in the absence of cardiac involvement, the presence of vagal dysfunction remains controversial. In a cross-sectional study, we compared patients with Chagas disease without cardiac involvement and healthy individuals by three different methods to determine whether vagal dysfunction is present in the early phase of Chagas disease. Methods Sixty-one patients with Chagas disease without cardiac involvement and 38 controls were submitted to respiratory sinus arrhythmia test and 24-hour Holter monitoring. Vagal heart influences were assessed by the expiratory/inspiratory (E/I) ratio, time-domain indexes of heart rate variability (HRV), and by the quantification of a S-dimensional return map. Results The two groups were comparable in terms of left ventricular ejection fraction and left ventricular end-diastolic dimension. Compared with the control group, patients with Chagas disease had significantly lower values of the E/I ratio (mean +/- SD: 1.38 +/- 0.02 and 1.25 +/- 0.02, P < .004) and short-term indexes of HRV (median [interquartile range]-rMSSD: 23 [18-27] and 17 [13-23], P = .00;pNN50: 11 [7-17] and 6 [2-12], P = .00). P-3, a beat-to-beat HRV index derived from the 3-dimensional return map, also was significantly reduced in the Chagas disease group (mean +/- SD: 118 +/- 5 vs 100 +/- 4, P = .00). None of these indexes of vagal heart control were significantly correlated with left ventricular function or to the presence of esophageal radiologic abnormalities. Conclusion Parasympathetic dysautonomia is an independent and early phenomenon in Chagas disease and may precede left ventricular systolic dysfunction.

关键词：自主神经系统疾病/病因学自主神经系统疾病/病理生理学 Chagas病/并发症 Chagas病/病理生理学昼夜节律疾病恶化超声心动描记术多普勒心电描记术便携式心率心室/神经支配心室/病理生理学每搏输出量心缩期迷走神经/病理生理学青少年成年人女(雌)性人类男(雄)性中年人

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Time-varying spectral analysis of heart rate and left ventricular pressure variability during balloon coronary occlusion in humans - A sympathoexcitatory response to myocardial ischemia

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JOURNAL OF THE AMERICAN COLLEGE OF CARDIOLOGY 1999年第7期34卷 1924-1931页

作者： Joho, S Asanoi, H Remah, HA Igawa, A Kameyama, T Nozawa, T Umeno, K Inoue, H Toyama Med & Pharmaceut Univ Dept Internal Med 2 Toyama 9300194 Japan Toyama Med & Pharmaceut Univ Dept Physiol 1 Toyama 9300194 Japan

OBJECTIVES We assessed time-varying spectral components of heart rate and left ventricular (LV) pressure variability during coronary angioplasty to elucidate dynamic autonomic responses to transient myocardial ischemia. BACKGROUND Sympathoexcitatory reflexes elicited by acute coronary occlusion are rarely addressed in the clinical settings because of a lack of technique to monitor transient changes in sympathetic activation. METHODS RR interval and LV pressure and volume were serially recorded in 14 patients with effort angina during balloon coronary angioplasty. Wavelet analysis was applied for determination of nonstationary spectral components of RR interval and LV peak pressure variability. RESULTS The wavelet analysis revealed that coronary occlusion provoked low-frequency (LF) fluctuations of RR interval (seven patients) and LV peak pressure (six patients) at 0.06 +/- 0.01 Hz, but not in the remaining patients. Following the balloon inflation, the LF component of RR interval began to increase after the onset of myocardial ischemia, peaked at about 80 s, and then declined in the: late phase of inflation. Consequently, the ratio of low to high frequency component rose to be significantly greater in the LF augmentation group than in the no LF augmentation group in the middle phase of coronary occlusion. The patients with no LF augmentation had little evidence of myocardial ischemia as reflected by changes in ST segment and LV systolic function during coronary occlusion. CONCLUSIONS The wavelet analysis of RR interval and LV pressure variability clearly showed a dynamic profile of spectral components in response to transient coronary artery occlusion. The resultant regional myocardial ischemia elicited a profound sympathoexcitatory response followed by a gradual suppression. This method provides a useful tool to gain a new insight into the nonstationary autonomic influence on the cardiovascular system. (C) 1999 by the American College of Cardiology.

关键词：血管成形术气囊冠状动脉收缩冠心病/病理生理学冠心病/治疗冠状血管/神经支配冠状血管/病理生理学心电描记术兴奋性突触后电位/生理学心率/生理学测压法心肌缺血/病理生理学反射时间因素迷走神经/病理生理学心室压/生理学成年人老年人女(雌)性人类男(雄)性中年人

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CARDIAC-ARRHYTHMIAS IN SPACE - ROLE OF VAGOTONIA

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ACTA ASTRONAUTICA 1981年第7期8卷 795-801页

作者： LEGUAY, G SEIGNEURIC, A Service de Medecine Aeronautique Hopital d'Instruction des Armees Dominique Larrey Versailles France.

Rhythm disorders observed in space have always been minor but they are not unfrequent. They include: ventricular or supra-ventricular extrasystoles, nodal arrhythmias, auriculo-ventricular conduction disorders. There are several etiopathogenetic hypotheses: a strict selection must permit its elimination of an underlying heart disease; the potassium deficiency is often advanced but its role is not certain; the role of catecholamines is also discussed; the role of hypervagotony is extensively analysed as great clinical and electro-cardiographic evidence speaks for it. It can induce disorders which are more serious than those observed so far, particularly fibrillation or intermittent atrial flutter; weightlessness itself could partly condition the vagotonic state; and the effects of fluid shifts are also discussed from this point of view. The possible therapies for various atrial, nodal, ventricular disorders are reviewed, with greater detail for vagal atrial arrhythmias.

关键词：适应生理学航天医学肾上腺素/代谢体液转移/生理学低钾血症去甲肾上腺素/代谢钾缺乏宇宙飞行迷走神经/病理生理学室性早搏复合征人类

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EFFECT OF AUTONOMIC NEURAL INFLUENCES ON CARDIOVASCULAR CHANGES INDUCED BY CORONARY-OCCLUSION

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AMERICAN HEART JOURNAL 1975年第6期89卷 766-774页

作者： CORR, PB GILLIS, RA GEORGETOWN UNIV SCH MED & DENTDEPT PHARMACOLWASHINGTONDC 20006

The influence of vagal stimulation and/or betaadrenergic receptor blockade on the heart rate, blood pressure, contractile force, and cardiac rhythm was evaluated in chloralose-anesthetized cats subjected to occlusion of the anterior descending coronary artery. Occlusion performed in 25 control animals produced significant decreases in heart rate (−22.9 ± 4.4 beats per minute), blood pressure (−19.2 ± 2.4 mm. Hg), and contractile force (−21.6 ± 6.3 per cent). Death due to ventricular fibrillation occurred in five out of 25 animals. Coronary occlusion performed in the presence of vagal nerve stimulation resulted in similar decreases in blood pressure, whereas the decreases in contractile force were significantly greater than in control animals. In addition, the time to onset of the arrhythmias occurring in the vagus-stimulated group was increased. Death due to ventricular fibrillation was similar to control animals (i.e., two of seven, or 28 per cent). Blockade of beta-adrenergic receptors with propranolol (0.75 mg. per kilogram) resulted in the usual decreases in rate, pressure, and force with occlusion but the duration of arrhythmias was shortened. The incidence of ventricular fibrillation was not different from that of the control animals. The combination of propranolol and vagal stimulation also failed to confer protection against ventricular fibrillation. Propranolol was observed to prevent the large decrease in contractile force seen with vagal stimulation. These results suggest that: (1) increasing vagal tone above the level existing after acute myocardial infarction does not decrease mortality, (2) propranolol pretreatment does not affect the incidence of ventricular fibrillation induced by coronary occlusion, (3) the duration of the arrhythmia after coronary occlusion is effectively shortened with propranolol, and (4) cardiac beta-adrenergic receptors do not appear to be involved in the decreases in heart rate, blood pressure, and contractile force seen with

关键词：自主神经系统/病理生理学血压/药物作用电刺激心电描记术心脏/病理生理学心脏传导系统/病理生理学心率/药物作用心肌收缩/药物作用心肌梗死/病理生理学普萘洛尔/药理学受体肾上腺素能时间因素迷走神经/病理生理学动物猫女(雌)性男(雄)性

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Dynamics of low-frequency R-R interval oscillations preceding spontaneous ventricular tachycardia

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AMERICAN HEART JOURNAL 2000年第1期139卷 126-133页

作者： Shusterman, V Aysin, B Weiss, R Brode, S Gottipaty, V Schwartzman, D Anderson, KP Univ Pittsburgh Med Ctr Cardiac Electrophysiol Program Cardiovasc InstUPHS Pittsburgh PA 15260 USA

Background Increased sympathetic activity is believed to be an important trigger of sustained ventricular tachyarrhythmias (VT) and is believed to be responsible for the increased heart rate that we and others have reported before the onset of spontaneous VT. However, in the patients reported herein, heart rate variability (HRV) indexes that reflect sympathetic activity unexpectedly declined, whereas heart rate increased. To explain this apparent paradoxic behavior, we tested the hypothesis that baseline levels of HRV determine its reaction to short-term autonomic perturbations before the onset of VT. Methods and Results Holter electrocardiograms from 47 patients (ejection fraction 36% +/- 15%) with recorded VT were analyzed. Frequency domain HRV indexes (low-frequency power [LFP] 0.04 to 0.15 Hz, high-frequency power [HFP] 0.15 to 0.4 Hz, and fetal power [TP] 0.01 to 0.4 Hz) were studied in 5-minute intervals and over a period of 24 hours. Patients were divided into those with a decrease in LFP in the 2-hour period before VT (group A, n = 32) and those with an increase or no change (group B, n = 15). The data were logarithmically transformed. Heart rate increased 15 minutes before the onset of VT compared with the 24-hour mean in both groups (group A: 80.3 +/- 15.4 to 86.1 +/- 20.0 beats/min, P = .005;group B: 80.6 +/- 13.5 to 86.7 +/- 14.0 beats/min, P = .017). Group A had higher TP, LFP, and LFP/HFP 2 hours before VT, and these variables decreased 15 minutes before the onset of VT (TP From 7.31 +/- 1.28 to 6.88 +/- 1.35, LFP from 6.09 +/- 1.28 to 5.38 +/- 1.33, LFP/HFP from 1.33 +/- 0.89 to 0.96 +/- 0.80, P < .001 for all 3 variables). HFP also decreased 15 minutes before VT compared with 2 hours (from 4.78 +/- 1.05 to 4.49 +/- 1.24, P = .028). In group B, which had lower baseline TP, LFP, and LFP/HFP at 2 hours before VT, these variables increased 15 minutes before the event (TP from 6.41 +/- 1.41 to 6.86 +/- 1.42, P = .004;LFP from 4.59 +/- 1.51 to 4.95 +/- 0.6

关键词：昼夜节律心电描记术便携式心率/生理学预后每搏输出量心动过速室性/病理生理学迷走神经/病理生理学老年人女(雌)性人类男(雄)性中年人

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Distinct hemodynamic profiles in patients with vasovagal syncope: A heterogeneous population

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JOURNAL OF THE AMERICAN COLLEGE OF CARDIOLOGY 2000年第6期35卷 1470-1477页

作者： Shen, WK Low, PA Rea, RF Lohse, CM Hodge, DO Hammill, SC Mayo Clin & Mayo Fdn Div Cardiovasc Dis & Internal Med Rochester MN 55905 USA Mayo Clin & Mayo Fdn Peripheral Neuropathy Res Lab Rochester MN 55905 USA Mayo Clin & Mayo Fdn Biostat Sect Rochester MN 55905 USA

OBJECTIVE The objective was to investigate mechanisms of vasovagal syncope by identifying laboratory techniques that characterize cardiovascular profiles in patients With vasovagal syncope. BACKGROUND The triggering mechanisms of vasovagal syncope are complex. The patient population is likely heterogeneous. We hypothesized that distinct hemodynamic profiles are definable with provocative maneuvers. METHODS Three groups of subjects were matched for age and gender: 16 patients with a history of syncope and an inducible vasovagal response during passive tilt table testing (70 degrees, 45 min, group I), 16 with a history of syncope, negative passive tilt table testing but positive isoproterenol tilt table testing (0.05 mu g/kg per min, 70 degrees, 10 min, group II), and 16 control subjects. Beat-to-beat hemodynamic functions were determined noninvasively by photoplethysmography and impedance cardiography. RESULTS At baseline, hemodynamic functions were not different among the three groups (supine). In response to tilt before any symptoms developed, total peripheral resistance decreased 99% +/- 14%, in group I from baseline supine to tilt position but increased 27% +/- 18% in group II and 28% +/- 17% in controls (p < 0.001). Responses to isoproterenol were not significantly different between group LT and controls in supine position. In response to tilt during isoproterenol infusion before any symptoms developed, total peripheral resistance decreased 24% +/- 20% in group II and increased 20% +/- 48% in controls (p = 0.002). CONCLUSIONS Group I patients may have impaired ability to increase vascular resistance during orthostatic stress. The inability to overcome isoproterenol-induced vasodilatation during tilt is important in triggering a vasovagal response in group II patients. These data suggest that the population with vasovagal response is heterogeneous. Distinct hemodynamic profiles in response to various provocative maneuvers are definable with noninvasive, continuou

关键词：血流动力学/药物作用血流动力学/生理学异丙肾上腺素拟交感神经药晕厥血管迷走神经性/诊断晕厥血管迷走神经性/病理生理学倾斜台试验迷走神经/病理生理学血管阻力/药物作用血管阻力/生理学成年人女(雌)性人类男(雄)性中年人

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SORORAL OCCURRENCE OF DIFFUSE ESOPHAGEAL SPASM

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AMERICAN JOURNAL OF DIGESTIVE DISEASES 1976年第10期21卷 901-904页

作者： KAYE, MD JOHNSON, WP UNIV COLORADO SCH MED DEPT MED DENVER CO 80220 USA

Two sisters with classical symptoms, radiological appearances and manometric features of diffuse esophageal spasm were described. This is the 1st documentation of familial occurrence of this disorder.

关键词：食管疾病/病因学食管疾病/遗传学食管疾病/放射摄影术测压法痉挛/病因学痉挛/遗传学痉挛/放射摄影术迷走神经/病理生理学女(雌)性人类中年人

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Baroreflex and non-baroreflex modulation of vagal cardiac control after myocardial infarction

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AMERICAN JOURNAL OF CARDIOLOGY 1999年第5期84卷 525-529页

作者： Grassi, G Seravalle, G Giannattasio, C Saino, A Turri, C Mancia, G Univ Milan Osped S Gerardo Cattedra Med Interna I-20052 Monza Italy Osped Maggiore Ctr Fisiol Clin & Ipertens IRCCS I-20122 Milan Italy Inst Auxol Italiano Milan Italy

Vagal control of sinus node exerted by arterial baroreceptors is markedly impaired 48 hours after acute myocardial infarction (AMI), but it recovers 10 days later. However, it is unknown whether this recovery is peculiar to baroreceptor vagal control or reflects normalization of the overall vagal modulation of heart rate, In 21 untreated patients (aged 51 +/- 3 years, mean a SEM) studied 10 +/- 1 and 21 +/- 1 days after an AMI and in 13 healthy controls (aged 47 +/- 2 years), we examined the increases in RR interval (electrocardiogram) induced by carotid baroreceptor stimulation via a neck chamber and by immersion of the face in iced water for 15 seconds (diving reflex). Both 10 and 21 days after AMI, baseline blood pressure and RR interval values were superimposable to those obtained in controls. Ten days after AMI, the bradycardic responses to carotid baroreceptor stimulation were similar to those seen in controls (maximal RR interval lengthenings: 248 +/- 34 vs 270 +/- 31 ms, respectively, p = NS) and remained virtually unchanged later. In contrast, the bradycardic response to diving was reduced in patients after AMI compared with controls (maximal RR interval lenghtenings: 203 +/- 43 vs 325 +/- 52 ms, respectively, p <0.05) and did not improve later. Thus, in AMI recovery of the early impairment of baroreceptor- heart rate control does not reflect normalization of vagal cardiac control, which remains lower than normal values at a time when the baroreflex is restored. (C) 1999 by Excerpta Medica, Inc.

关键词：血压/生理学颈动脉体/病理生理学心电描记术心脏/神经支配心率/生理学浸渍/病理生理学心肌梗死/病理生理学压力感受器/病理生理学参考值反射/生理学窦房结/病理生理学迷走神经/病理生理学女(雌)性人类男(雄)性中年人

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