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Plappert F, Wallman M, Abdollahpur M, Platonov PG, Östenson S, Sandberg F. An atrioventricular node model incorporating autonomic tone. Front Physiol 2022; 13:976468. [PMID: 36187793 PMCID: PMC9520409 DOI: 10.3389/fphys.2022.976468] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Accepted: 08/10/2022] [Indexed: 11/19/2022] Open
Abstract
The response to atrial fibrillation (AF) treatment is differing widely among patients, and a better understanding of the factors that contribute to these differences is needed. One important factor may be differences in the autonomic nervous system (ANS) activity. The atrioventricular (AV) node plays an important role during AF in modulating heart rate. To study the effect of the ANS-induced activity on the AV nodal function in AF, mathematical modelling is a valuable tool. In this study, we present an extended AV node model that incorporates changes in autonomic tone. The extension was guided by a distribution-based sensitivity analysis and incorporates the ANS-induced changes in the refractoriness and conduction delay. Simulated RR series from the extended model driven by atrial impulse series obtained from clinical tilt test data were qualitatively evaluated against clinical RR series in terms of heart rate, RR series variability and RR series irregularity. The changes to the RR series characteristics during head-down tilt were replicated by a 10% decrease in conduction delay, while the changes during head-up tilt were replicated by a 5% decrease in the refractory period and a 10% decrease in the conduction delay. We demonstrate that the model extension is needed to replicate ANS-induced changes during tilt, indicating that the changes in RR series characteristics could not be explained by changes in atrial activity alone.
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Affiliation(s)
- Felix Plappert
- Department of Biomedical Engineering, Lund University, Lund, Sweden
- *Correspondence: Felix Plappert,
| | - Mikael Wallman
- Department of Systems and Data Analysis, Fraunhofer-Chalmers Centre, Gothenburg, Sweden
| | | | - Pyotr G. Platonov
- Department of Cardiology, Clinical Sciences, Lund University, Lund, Sweden
| | - Sten Östenson
- Department of Internal Medicine and Department of Clinical Physiology, Central Hospital Kristianstad, Kristianstad, Sweden
| | - Frida Sandberg
- Department of Biomedical Engineering, Lund University, Lund, Sweden
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Chopra N. A unique case of pulmonary embolism presenting as a paroxysmal atrial tachycardia instigated only by recumbency and stooping. HeartRhythm Case Rep 2016; 2:404-406. [PMID: 28491721 PMCID: PMC5419948 DOI: 10.1016/j.hrcr.2016.05.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Jorat MV, Eftekharzadeh SA, Mirzaei M, Owlia M, Sartipzadeh NH, Salami MA, Vafaeenasab M, Rahimianfar AA, Shamibaf M, Jafarieh M, Seyfpourshouraki Z, Sarebanhassanabadi M. Evaluation of the effect of radiofrequency catheter ablation on autonomic function in patients with atrioventricular nodal reentrant tachycardia by head-up tilt table test. Adv Biomed Res 2015; 4:96. [PMID: 26015922 PMCID: PMC4434488 DOI: 10.4103/2277-9175.156662] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2014] [Accepted: 07/28/2014] [Indexed: 11/23/2022] Open
Abstract
Background: One of the recommended treatments for atrioventricular nodal reentrant tachycardia (AVNRT), is radiofrequency catheter ablation (RFCA). However, RFCA may affect the autonomic system. This study aims to evaluate the effect of RFCA on autonomic system in patients with PSVT by head-up tilt table (HUTT) test. Materials and Methods: In a before–after study, 22 patients with PSVT were enrolled. Data were collected with a data collection form that included two parts. Electrocardiogram (ECG), echocardiogram, 24-h Holter monitoring, HUTT test, heart rate variability (HRV) indexes, and symptoms of all patients were recorded 24 h before and 1 month after the ablation. Wilcoxon, McNemar, Mann–Whitney U, and Chi-square tests were used to analyze the data. Results: Of the total 22 patients, 31.8% were male and 68.2% were female. There were significant differences in heart palpitation (P < 0.0001) and non-specific symptoms (P = 0.031) and no significant difference in head-up tilt test results and HRV indices before and after RFCA. The results showed that there were no significant differences in specific and non-specific symptoms in patients with AVNRT with positive and negative HUTT before and after RFCA. Conclusions: The observed difference in heart palpitation and non-specific symptoms emphasized the role of AVNRT in causing these symptoms. Autonomic dysfunction is more probably an accompanying condition of AVNRT than causing symptoms. We could not find any significance in the results of HUTT after RFCA. HUTT cannot determine or predict the symptoms after RFCA.
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Affiliation(s)
- Mohammad Vahid Jorat
- Yazd Cardiovascular Research Center, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
| | | | - Masoud Mirzaei
- Yazd Cardiovascular Research Center, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
| | - Mohammadbagher Owlia
- Yazd Cardiovascular Research Center, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
| | | | - Maryam-Alsadat Salami
- Yazd Cardiovascular Research Center, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
| | | | - Ali Akbar Rahimianfar
- Yazd Cardiovascular Research Center, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
| | - Marzieh Shamibaf
- Yazd Cardiovascular Research Center, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
| | - Minoo Jafarieh
- Yazd Cardiovascular Research Center, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
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Rodrigo R, Cereceda M, Castillo R, Asenjo R, Zamorano J, Araya J, Castillo-Koch R, Espinoza J, Larraín E. Prevention of atrial fibrillation following cardiac surgery: basis for a novel therapeutic strategy based on non-hypoxic myocardial preconditioning. Pharmacol Ther 2008; 118:104-27. [PMID: 18346791 DOI: 10.1016/j.pharmthera.2008.01.005] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2008] [Accepted: 01/24/2008] [Indexed: 02/06/2023]
Abstract
Atrial fibrillation is the most common complication of cardiac surgical procedures performed with cardiopulmonary bypass. It contributes to increased hospital length of stay and treatment costs. At present, preventive strategies offer only suboptimal benefits, despite improvements in anesthesia, surgical technique, and medical therapy. The pathogenesis of postoperative atrial fibrillation is considered to be multifactorial. However oxidative stress is a major contributory factor representing the unavoidable consequences of ischemia/reperfusion cycle occurring in this setting. Considerable evidence suggests the involvement of reactive oxygen species (ROS) in the pathogenic mechanism of this arrhythmia. Interestingly, the deleterious consequences of high ROS exposure, such as inflammation, cell death (apoptosis/necrosis) or fibrosis, may be abrogated by a myocardial preconditioning process caused by previous exposure to moderate ROS concentration known to trigger survival response mechanisms. The latter condition may be created by n-3 PUFA supplementation that could give rise to an adaptive response characterized by increased expression of myocardial antioxidant enzymes and/or anti-apoptotic pathways. In addition, a further reinforcement of myocardial antioxidant defenses could be obtained through vitamins C and E supplementation, an intervention also known to diminish enzymatic ROS production. Based on this paradigm, this review presents clinical and experimental evidence supporting the pathophysiological and molecular basis for a novel therapeutic approach aimed to diminish the incidence of postoperative atrial fibrillation through a non-hypoxic preconditioning plus a reinforcement of the antioxidant defense system in the myocardial tissue.
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Affiliation(s)
- Ramón Rodrigo
- Molecular and Clinical Pharmacology Program, Institute of Biomedical Sciences, Faculty of Medicine, University of Chile, Santiago, Chile.
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Makai A, Csillik A, Csanádi Z, Sághy L, Forster T, Rudas L. Unusual case of orthostatic tachycardia. Orv Hetil 2007; 148:77-80. [PMID: 17344123 DOI: 10.1556/oh.2007.27850] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Bevezetés:
Az orthostasis intolerancia, az orthostaticus tachycardia gyakran jelez hypovolemiát, gyógyszermellékhatást vagy autonóm elégtelenséget. Az orthostasisszal provokálható tachyarrhythmia ritka jelenség, emelt fejvégű billenőasztal vizsgálatsorozatokban csak elvétve fordul elő.
Célkitűzés:
A szerzők egy olyan beteget mutatnak be, akinek AV-csomó reentry tachycardiás paroxysmusait függőleges testhelyzet provokálta.
Módszer:
Vagusmanőverekkel az anterográd lassú pálya vezetésének blokkolása révén sikeresen szüntették a tachycardiát.
Eredmények:
Figyelemre méltó, hogy a vagusmanőverek csak vízszintes testhelyzetben bizonyultak hatásosnak.
Következtetés:
Ez a megfigyelés felhívja a figyelmet a manőverek pontos kivitelezésének fontosságára.
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Affiliation(s)
- Attila Makai
- Szegedi Tudományegyetem, Altalános Orvostudományi Kar, Aneszteziológiai és Intenzív Terápiás Intézet, Altalános Intenzív Részleg, Szeged, Korányi fasor 7, 6720.
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Brignole M, Gianfranchi L, Menozzi C, Raviele A, Oddone D, Lolli G, Bottoni N. Role of autonomic reflexes in syncope associated with paroxysmal atrial fibrillation. J Am Coll Cardiol 1993; 22:1123-9. [PMID: 8409051 DOI: 10.1016/0735-1097(93)90426-2] [Citation(s) in RCA: 75] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
OBJECTIVES The purpose of this study was to evaluate the role of autonomic reflexes in the genesis of syncope associated with the onset of paroxysmal atrial fibrillation. BACKGROUND Syncope associated with paroxysmal atrial fibrillation has been interpreted as an ominous finding predictive of rapid ventricular rates. However, various mechanisms may be involved when heart rate is not particularly high. METHODS Forty patients (age 60 +/- 14 years, 20 men, 20 women) with syncope and atrial fibrillation were compared with atrial fibrillation without syncope. Carotid sinus massage and head-up tilt testing (at 60 degrees for 60 min at baseline and during isoproterenol infusion) were performed during sinus rhythm. A positive response was defined as the induction of syncope. Atrial fibrillation was also induced on a tilt table at 60 degrees by means of short bursts of atrial pacing. RESULTS Results of carotid sinus massage were positive in 15 (37%) of 40 patients but in no control subjects (p = 0.002). Head-up tilt test findings were positive in 25 (66%) of 38 patients and in 2 (12%) of 16 control subjects (p = 0.0004). The induction of atrial fibrillation in the upright position elicited syncope in 16 (42%) of 38 patients but in none of 16 control subjects (p = 0.001). At the beginning of atrial fibrillation, systolic blood pressure was lower in patients than in control subjects (88 +/- 32 vs. 127 +/- 32 mm Hg), whereas mean heart rate was similar (142 +/- 35 vs. 134 +/- 25 beats/min). The correlation between heart rate and systolic blood pressure was weak (r = 0.35), and in five patients syncope occurred at a heart rate < or = 130 beats/min. At the time of syncope, heart rate decreased (-12 +/- 21 beats/min) in patients with induced syncope, whereas it remained unchanged in patients without induced syncope (+1 +/- 17 beats/min, p = 0.04) or slightly increased in control subjects (+9 +/- 21 beats/min, p = 0.009). CONCLUSIONS Patients with syncope associated with paroxysmal atrial fibrillation are predisposed to an abnormal neural response during both sinus rhythm and arrhythmia. In some patients the onset of atrial fibrillation triggers vasovagal syncope.
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Affiliation(s)
- M Brignole
- Laboratory of Electrophysiology and Pacing, Ospedali Riuniti, Lavagna, Italy
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Leitch JW, Klein GJ, Yee R, Leather RA, Kim YH. Syncope associated with supraventricular tachycardia. An expression of tachycardia rate or vasomotor response? Circulation 1992; 85:1064-71. [PMID: 1537103 DOI: 10.1161/01.cir.85.3.1064] [Citation(s) in RCA: 111] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
BACKGROUND Syncope in patients with supraventricular tachycardia has been suggested to be an ominous finding, predictive of rapid rates during tachycardia. METHODS AND RESULTS To explore the mechanism of syncope during supraventricular tachycardia, tachycardia was induced in the supine position and after passive head-up tilting to 60 degrees in 13 patients with atrioventricular (AV) node reentry, eight patients with AV reentry, and one patient with atrial tachycardia. Tilt testing was also performed in sinus rhythm for 30 minutes (the last 15 minutes with isoproterenol infusion). Mean +/- SEM age was 38 +/- 3 years, and 11 patients had a history of syncope (median number of syncopal episodes, three; range, one to 30). The cycle length of tachycardia when upright was shorter than when supine (297 +/- 9 compared with 357 +/- 10 msec, p less than 0.001), and mean blood pressure fell to a greater extent after the onset of tachycardia (fall in mean blood pressure, 53 +/- 6 compared with 24 +/- 3 mm Hg, p less than 0.001). Mean blood pressure correlated significantly with tachycardia cycle length when supine (r = 0.58, p = 0.005) but not when tilted upright (r = 0.18, p = 0.45). Syncope occurred in seven patients during upright tachycardia. These seven patients had a greater fall in mean blood pressure with upright tachycardia than the 15 patients without syncope (fall in mean blood pressure, 70 +/- 4 compared with 45 +/- 5 mm Hg, p = 0.01), but there was no difference in the tachycardia cycle length (311 +/- 10 compared with 290 +/- 11 msec, p = 0.29). Six of the seven patients with tachycardia-induced syncope also had syncope with tilt testing in sinus rhythm compared with four of the 15 patients without tachycardia-induced syncope (p = 0.02). CONCLUSIONS These data support the view that syncope during supraventricular tachycardia is related to vasomotor factors and does not predict a more rapid tachycardia rate.
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Affiliation(s)
- J W Leitch
- Department of Medicine, University of Western Ontario, London, Canada
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