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Victor M. Wiegant - One of the best experts on this subject based on the ideXlab platform.
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CRH Signalling in the Bed Nucleus of the Stria Terminalis is Involved in Stress-Induced Cardiac Vagal Activation in Conscious Rats
Neuropsychopharmacology, 2001Co-Authors: Marjoleen J.m.a. Nijsen, Gerda Croiset, Michaela Diamant, David De Wied, Victor M. WiegantAbstract:The bed nucleus of the stria terminalis (BNST) is involved in autonomic and behavioral reactions to fearful stimuli and contains corticotropin-releasing hormone (CRH) fibers and terminals. The role of CRH in the medial part of the BNST in the regulation of heart rate (HR) and PQ Interval of the electrocardiogram was studied under resting conditions and conditioned fear stress in freely moving rats. Microinfusion of CRH (0.2 μg/0.6 μl) in the medial BNST under resting conditions significantly enhanced HR as compared to saline treatment, but did not reduce the PQ Interval, indicating that exogenous CRH in the medial BNST can activate both the sympathetic and parasympathetic cardiac outflow. In addition, CRH induced a slight increase in gross locomotor activity, an effect that succeeded the tachycardiac response, indicating that the HR response was not a consequence of increased locomotor activity, but likely a direct effect of CRH. CF was induced by 10-min forced exposure to a cage in which the rat had experienced footshocks (5 × 0.5 mA × 3s) the day before. α-helical CRH(9–41) (αhCRH; 5 μg/0.6 μl), a non-selective CRH receptor antagonist, or saline was infused into the medial BNST of rats prior to CF. CF induced freezing behavior, associated with an increase in HR and PQ Interval, indicating activation of sympathetic and vagal outflow to the heart. αhCRH significantly reduced the PQ response, but enhanced the tachycardia, suggesting inhibition of vagal activity. In addition, α-helical CRH(9–41) reduced the freezing response. Taken together, the data provide first evidence that CRH, released in the medial BNST during stress, contributes to cardiac stress responses, particularly by activating vagal outflow.
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The Role of the CRH Type 1 Receptor in Autonomic Responses to Corticotropin-Releasing Hormone in the Rat
Neuropsychopharmacology, 2000Co-Authors: Marjoleen J.m.a. Nijsen, Gerda Croiset, Michaela Diamant, David De Wied, Adrie W. Bruijnzeel, Ruben Stam, Victor M. WiegantAbstract:The involvement of the corticotropin-releasing hormone (CRH) type 1 receptor in CRH-induced cardiac responses was studied in freely moving rats. Intracerebroventricular (icv) infusion of 2 μ g CRH under resting conditions resulted in a significant increase in heart rate (HR), but did not significantly affect the PQ Interval of the electrocardiogram. This effect involves sympathetic nervous system (SNS) activation, since CRH-treatment resulted in a marked increase in plasma norepinephrine (NE) and epinephrine (E), and sympathetic blockade by subcutaneously injected atenolol (1 mg/kg), a β 1-selective adrenergic antagonist, completely prevented the CRH-induced tachycardia. CRH infusion after sympathetic blockade resulted in an elongation of the PQ Interval, indicating CRH-induced vagal activation. Gross locomotor activity (GA) was determined to study its possible indirect effects on cardiac activity. Although CRH induced a marked increase in GA, this effect followed the tachycardiac response, indicating that the HR response was not a consequence of increased locomotor activity, but was a direct effect of icv CRH. Treatment with CP-154,526 (icv, 10 or 25 μ g), a selective CRH type 1 receptor antagonist, did not affect baseline HR, plasma NE and E, whereas it partially blocked the CRH-induced increase in HR, plasma NE and E levels. CP-154,526 treatment had no significant effects on baseline or CRH-induced changes in GA. These results indicate that CRH activates the sympathetic nervous system at least in part via the CRH type 1 receptor.
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Endogenous corticotropin-releasing hormone inhibits conditioned-fear-induced vagal activation in the rat
European journal of pharmacology, 2000Co-Authors: Marjoleen J.m.a. Nijsen, Gerda Croiset, Michaela Diamant, R. Stam, David De Wied, Patrick Joseph Gerardus Hendrikus Kamphuis, Adrie W. Bruijnzeel, Victor M. WiegantAbstract:The role of the endogenous corticotropin-releasing hormone (CRH) system in the regulation of heart rate, PQ Interval (a measure of vagal activity), gross activity and release of adrenocorticotropic hormone (ACTH), noradrenaline and adrenaline into the blood during conditioned fear was studied in freely moving rats. Intracerebroventricular (i.c.v.) infusion of alpha-helical CRH-(9-41) (10 microgram/3 microliter), a non-selective CRH receptor antagonist, under resting conditions had no significant effect on gross activity, heart rate and PQ Interval, indicating that alpha-helical CRH at this dose was devoid of agonist effects. Conditioned fear was induced by 10 min forced exposure to a cage in which the rat had experienced footshocks (5x0.5 mAx3 s) 1 day before. Conditioned-fear rats showed freezing behaviour, associated with an increase in heart rate, PQ Interval, noradrenaline and adrenaline, indicating that the conditioned-fear-induced cardiac effects were the result of coactivation of the sympathetic and parasympathetic nervous system. The i.c.v. pre-treatment of rats with alpha-helical CRH significantly reduced the conditioned-fear-induced tachycardiac and ACTH response, and enhanced the increase in PQ Interval, without affecting the noradrenaline and adrenaline response. These results suggest that endogenous CRH reduces the vagal response to conditioned-fear stress in rats. To test this, rats were pre-treated with atropine methyl nitrate (0.3 mg/kg, subcutaneously; s.c.), a peripherally acting cholinergic receptor antagonist. This resulted in a complete blockade of the alpha-helical CRH-induced decrease in heart rate response and increase in PQ Interval. From these findings, it is concluded that endogenous CRH in the brain inhibits vagal outflow induced by emotional stress.
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Conditioned fear-induced tachycardia in the rat; vagal involvement
European Journal of Pharmacology, 1998Co-Authors: Marjoleen J.m.a. Nijsen, Gerda Croiset, Michaela Diamant, R. Stam, Dianne Delsing, David De Wied, Victor M. WiegantAbstract:Abstract The effects of conditioned fear on gross activity, heart rate, PQ Interval, noradrenaline and adrenaline were studied in freely moving rats. Subcutaneous (s.c.) injections of atropine methyl nitrate (0.5 mg/kg) during rest resulted in a significant shortening of the PQ Interval, indicating that the PQ Interval can be used as a measure of vagal activity. Conditioned fear was induced by 10-min forced exposure to a cage in which the rat had previously experienced footshocks (5×0.5 mA×3 s). In non-shocked controls, an increase in gross activity was found and a pronounced tachycardia, without changes in PQ Interval. Conditioned fear rats showed immobility behaviour, associated with a less pronounced tachycardia and an increase in PQ Interval. Noradrenaline was similarly increased in both groups, whereas adrenaline was increased in conditioned fear rats only. To further evaluate the role of the vagus, rats were exposed to conditioned fear after pre-treatment with atropine methyl nitrate (0.5 mg/kg, s.c.). Again, immobility was observed with a concomitant tachycardia, but without an increase in PQ Interval. These results indicate that the autonomic nervous system is differentially involved in heart rate regulation in conditioned fear rats and in non-shocked controls: in non-shocked controls a predominant sympathetic nervous system activation results in an increase in heart rate, whereas in conditioned fear rats the tachycardiac response is attenuated by a simultaneous activation of sympathetic nervous system and parasympathetic nervous system.
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Vagal activation in novelty-induced tachycardia during the light phase in the rat.
Physiology & Behavior, 1998Co-Authors: Marjoleen J.m.a. Nijsen, Gerda Croiset, Michaela Diamant, M.h. Broekhoven, Victor M. WiegantAbstract:Abstract Nijsen, M. J. M. A., G. Croiset, M. Diamant, M. H. Broekhoven, D. De Wied and V. M. Wiegant. Vagal activation in novelty-induced tachycardia during the light phase in the rat. PHYSIOL BEHAV 63(2) 233–239, 1998.—The effects of repeated exposure to a novel test box on cardiac and behavioral activities (locomotion, rearing, grooming, scanning, and immobility) were studied in rats tested during the dark phase (“dark” rats) or the light phase (“light” rats) of the lighting cycle, using a telemetry system for registration of ECGs during the first and fifth tests. Heart rate (HR) was used to monitor sympathetic and parasympathetic activity; the PQ Interval was used to monitor parasympathetic activity. Behavior was videotaped simultaneously. In light rats, the first and fifth exposures to the test box resulted in higher increases of active behavior and HR than in dark rats, whereas the duration of the PQ Interval of the ECG was increased in light rats only. This indicates that in the light phase novelty induces active behavior associated with an increase in both sympathetic and vagal outflow, whereas in the dark phase behavioral activation is predominantly associated with increased sympathetic activity, without appreciable changes in vagal outflow. In addition, light rats showed less active behavior during the fifth than during the first exposure, indicating behavioral habituation. This behavioral habituation to the test box in the light phase coincided with vagal habituation (a diminution of the PQ Interval). The increase of the tachycardiac response during the fifth exposure as compared to the first exposure suggests that it is not likely that sympathetic outflow was part of the habituation process. In dark rats no behavioral or cardiac habituation was found.
Jens Cosedis Nielsen - One of the best experts on this subject based on the ideXlab platform.
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atrial fibrillation in patients with sick sinus syndrome the association with PQ Interval and percentage of ventricular pacing
Europace, 2012Co-Authors: Jens Cosedis Nielsen, Poul Erik Bloch Thomsen, Soren Hojberg, Mogens Moller, Sam Riahi, Dorthe Dalsgaard, Leif Spange Mortensen, Tonny Nielsen, Mogens Asklund, Elsebeth V FriisAbstract:Aims In the recently published DANPACE trial, incidence of atrial fibrillation (AF) was significantly higher with single-lead atrial (AAIR) pacing than with dual-chamber (DDDR) pacing. The present analysis aimed to evaluate the importance of baseline PQ-Interval and percentage of ventricular pacing (VP) on AF. Methods and results We analysed data on AF during follow-up in 1415 patients included in the DANPACE trial. In a subgroup of 650 patients with DDDR pacemaker, we studied whether %VP, baseline PQ-Interval, and programmed atrio-ventricular Interval (AVI) was associated with AF burden measured as time in mode-switch (MS) detected by the pacemaker. In the entire DANPACE study population, the incidence of AF was significantly higher in patients with baseline PQ-Interval >180 ms ( P 180 ms ( P = 0.028). No significant association was detected between %VP and %MS (Spearman's ρ 0.056, P = 0.154). %MS was not different between minimal-paced programmed AVI ≤ 100 and >100 ms (median value), respectively ( P = 0.60). Conclusions The present study indicates that a longer baseline PQ-Interval is associated with an increased risk of AF in patients with sick sinus syndrome. Atrial fibrillation burden is not associated with the percentage of VP or the length of the programmed AVI.
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atrioventricular conduction during long term follow up of patients with sick sinus syndrome
Circulation, 1998Co-Authors: Henning Rud Andersen, Leif Thuesen, Thomas Vesterlund, Poul Erik Bloch Thomsen, Jens Cosedis Nielsen, Anders Kirstein Pedersen, Peter Thomas MortensenAbstract:Background—It has been claimed that patients with sick sinus syndrome have an increased risk of developing AV block, but this has never been assessed prospectively. The aim of the present study was to evaluate in a prospective trial AV conduction during the long-term follow-up of patients with sick sinus syndrome. Methods—Two hundred twenty-five consecutive patients with sick sinus syndrome and intact AV conduction were randomized to undergo single-chamber atrial pacing (110 patients) or single-chamber ventricular pacing (115 patients). Follow-up after 3 months and then yearly included measurement of the PQ Interval and, in patients with atrial pacemakers, determination of the atrial stimulus–Q Intervals at pacing rates of 100 and 120 bpm. The occurrence of AV block in the atrial group was recorded. During follow-up (mean, 5.5±2.4 years), there was no change in PQ Interval in either group and no change in atrial stimulus–Q Intervals or Wenckebach block point in the atrial group. Four of 110 patients in th...
Poul Erik Bloch Thomsen - One of the best experts on this subject based on the ideXlab platform.
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atrial fibrillation in patients with sick sinus syndrome the association with PQ Interval and percentage of ventricular pacing
Europace, 2012Co-Authors: Jens Cosedis Nielsen, Poul Erik Bloch Thomsen, Soren Hojberg, Mogens Moller, Sam Riahi, Dorthe Dalsgaard, Leif Spange Mortensen, Tonny Nielsen, Mogens Asklund, Elsebeth V FriisAbstract:Aims In the recently published DANPACE trial, incidence of atrial fibrillation (AF) was significantly higher with single-lead atrial (AAIR) pacing than with dual-chamber (DDDR) pacing. The present analysis aimed to evaluate the importance of baseline PQ-Interval and percentage of ventricular pacing (VP) on AF. Methods and results We analysed data on AF during follow-up in 1415 patients included in the DANPACE trial. In a subgroup of 650 patients with DDDR pacemaker, we studied whether %VP, baseline PQ-Interval, and programmed atrio-ventricular Interval (AVI) was associated with AF burden measured as time in mode-switch (MS) detected by the pacemaker. In the entire DANPACE study population, the incidence of AF was significantly higher in patients with baseline PQ-Interval >180 ms ( P 180 ms ( P = 0.028). No significant association was detected between %VP and %MS (Spearman's ρ 0.056, P = 0.154). %MS was not different between minimal-paced programmed AVI ≤ 100 and >100 ms (median value), respectively ( P = 0.60). Conclusions The present study indicates that a longer baseline PQ-Interval is associated with an increased risk of AF in patients with sick sinus syndrome. Atrial fibrillation burden is not associated with the percentage of VP or the length of the programmed AVI.
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atrioventricular conduction during long term follow up of patients with sick sinus syndrome
Circulation, 1998Co-Authors: Henning Rud Andersen, Leif Thuesen, Thomas Vesterlund, Poul Erik Bloch Thomsen, Jens Cosedis Nielsen, Anders Kirstein Pedersen, Peter Thomas MortensenAbstract:Background—It has been claimed that patients with sick sinus syndrome have an increased risk of developing AV block, but this has never been assessed prospectively. The aim of the present study was to evaluate in a prospective trial AV conduction during the long-term follow-up of patients with sick sinus syndrome. Methods—Two hundred twenty-five consecutive patients with sick sinus syndrome and intact AV conduction were randomized to undergo single-chamber atrial pacing (110 patients) or single-chamber ventricular pacing (115 patients). Follow-up after 3 months and then yearly included measurement of the PQ Interval and, in patients with atrial pacemakers, determination of the atrial stimulus–Q Intervals at pacing rates of 100 and 120 bpm. The occurrence of AV block in the atrial group was recorded. During follow-up (mean, 5.5±2.4 years), there was no change in PQ Interval in either group and no change in atrial stimulus–Q Intervals or Wenckebach block point in the atrial group. Four of 110 patients in th...
Peter Thomas Mortensen - One of the best experts on this subject based on the ideXlab platform.
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atrioventricular conduction during long term follow up of patients with sick sinus syndrome
Circulation, 1998Co-Authors: Henning Rud Andersen, Leif Thuesen, Thomas Vesterlund, Poul Erik Bloch Thomsen, Jens Cosedis Nielsen, Anders Kirstein Pedersen, Peter Thomas MortensenAbstract:Background—It has been claimed that patients with sick sinus syndrome have an increased risk of developing AV block, but this has never been assessed prospectively. The aim of the present study was to evaluate in a prospective trial AV conduction during the long-term follow-up of patients with sick sinus syndrome. Methods—Two hundred twenty-five consecutive patients with sick sinus syndrome and intact AV conduction were randomized to undergo single-chamber atrial pacing (110 patients) or single-chamber ventricular pacing (115 patients). Follow-up after 3 months and then yearly included measurement of the PQ Interval and, in patients with atrial pacemakers, determination of the atrial stimulus–Q Intervals at pacing rates of 100 and 120 bpm. The occurrence of AV block in the atrial group was recorded. During follow-up (mean, 5.5±2.4 years), there was no change in PQ Interval in either group and no change in atrial stimulus–Q Intervals or Wenckebach block point in the atrial group. Four of 110 patients in th...
Andrzej Cwetsch - One of the best experts on this subject based on the ideXlab platform.
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Minimizing right ventricular pacing in patients with sinus node disease and prolonged PQ Interval: The impact on exercise capacity.
Cardiology journal, 2014Co-Authors: Krystian Krzyżanowski, Dariusz Michałkiewicz, Zbigniew Orski, Robert Wierzbowski, Robert Ryczek, Andrzej CwetschAbstract:Background: Several clinical and experimental studies have shown that unnecessary right ventricular pacing in sinus node disease can be detrimental. Inter- and intra-ventricular asynchrony imposed by right ventricular pacing may cause reduction in contractility and relaxation of left ventricle, worsening mitral regurgitation, regional redistribution of myocardial perfusion and oxygen consumption, and asymmetrical hypertrophy of left ventricular wall. In some patients, sinus node disease coexists with impaired atrioventricular conduction. The optimal pacing mode in this population is not determined. Minimizing right ventricular pacing can preserve inter- and intra-ventricular synchrony. On the other hand, longer atrioventricular delay may cause atrioventricular asynchrony. The aim of this study was to prospectively assess the impact of minimizing right ventricular pacing in patients with DDD pacemaker implanted for sinus node disease and prolonged PQ Interval on exercise capacity, cardiac function and quality of life. Methods: The study enrolled 50 consecutive patients with prolonged PQ Interval who were implanted with DDD pacemaker because of sinus node disease. Each patient was treated alternately with 2 pacing modes in random order for 4-month periods: conventional dualchamber pacing and dual-chamber minimal ventricular pacing (prolonged atrioventricular delay). At the end of each phase the following tests were performed: cardiopulmonary exercise testing, echocardiographic evaluation and quality of life assessment (SF36). Results: There was no significant relationship between pacing mode and cardiopulmonary parameters, echocardiographic parameters and quality of life. Conclusions: Sequential atrioventricular pacing may be a reasonable choice for treating patients with sinus node disease and prolonged PQ Interval.