Tachycardia-Induced Change of Atrial Refractory Period in Humans

Yu, Wen Chung; Chen, Shih Ann; Lee, Shih Huang; Tai, Ching Tai; Feng, An Ning; Kuo, Benjamin Ing Tiau; Ding, Yu An; Chang, Mau Song

doi:10.1161/01.cir.97.23.2331

Cited by 141 publications

(77 citation statements)

References 43 publications

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“…Shortening of the atrial ERP has been reported as one of the main underlying electrophysiological changes in patients with sustained AF [17]. Nevertheless, in our study the ERP measurements at different sites where not different between groups.…”

Section: Atrial Refractory Periodscontrasting

confidence: 63%

Inducibility of atrial fibrillation during electrophysiologic evaluation is associated with increased dispersion of atrial refractoriness

Oliveira

Silva

Timóteo

et al. 2009

International Journal of Cardiology

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The impact of atrial dispersion of refractoriness (Disp_A) in the inducibility and maintenance of atrial fibrillation (AF) has not been fully resolved. Aim: To study the Disp_A and the vulnerability (A_Vuln) for the induction of self-limited (b 60 s) and sustained episodes of AF. Methods and results: Forty-seven patients with paroxysmal AF (PAF): 29 patients without structural heart disease and 18 with hypertensive heart disease. Atrial effective refractory period (ERP) was assessed at five sites -right atrial appendage and low lateral right atrium, high interatrial septum, proximal and distal coronary sinus. We compared three groups: group A -AF not inducible (n = 13); group B -AF inducible, self-limited (n = 18); group C -AF inducible, sustained (n = 16). Age, lone AF, hypertension, left atrial and left ventricular (LV) dimensions, LV systolic function, duration of AF history, atrial flutter/tachycardia, previous antiarrhythmics, and Disp_A were analysed with logistic regression to determine association with A_Vuln for AF inducibility. The ERP at different sites showed no differences among the groups. Group A had a lower Disp_A compared to group B (47 ± 20 ms vs 82 ± 65 ms; p = 0.002), and when compared to group C (47 ± 20 ms vs 80 ± 55 ms; p = 0.008). There was no significant difference in Disp_A between groups B and C. By means of multivariate regression analysis, the only predictor of A_Vuln was Disp_A (p = 0.04). Conclusion: In patients with PAF, increased Disp_A represents an electrophysiological marker of A_Vuln. Inducibility of both self-limited and sustained episodes of AF is associated with similar values of Disp_A. These findings suggest that the maintenance of AF is influenced by additional factors.

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Section: Atrial Refractory Periodscontrasting

confidence: 63%

Inducibility of atrial fibrillation during electrophysiologic evaluation is associated with increased dispersion of atrial refractoriness

Oliveira

Silva

Timóteo

et al. 2009

International Journal of Cardiology

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“…The physiological consequences of relatively brief periods (up to several hours) of atrial tachycardia, believed to be functional, can be prevented by several drugs, including L-type Ca 2ϩ -channel blockers, renin-angiotensin system antagonists, and Na ϩ ,H ϩ -exchange inhibitors. [17][18][19][20] Longer-term consequences, caused by changed gene expression, are not suppressed by any of these compounds. 12,14,21 The only agent that has been found to prevent ERP changes and AF promotion by longer-term atrial tachycardia is mibefradil, 13,14 which is no longer available.…”

Section: Comparison With Previous Studies Of Drug Effects On Atrial Tmentioning

confidence: 99%

Effects of Antiarrhythmic Drugs on Fibrillation in the Remodeled Atrium

et al. 2003

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Background-The basis of the unique effectiveness of amiodarone for atrial fibrillation (AF) is poorly understood. The present study tested the hypothesis that amiodarone blocks electrical remodeling induced by atrial tachycardia. Methods and Results-Mongrel dogs were subjected to atrial tachycardia (400 bpm for 7 days) in the absence and presence of therapy with amiodarone, the class III cardiac antiarrhythmic drug dofetilide, or the class I agent flecainide begun 3 days before the onset of tachypacing and maintained until a final electrophysiological study. AF vulnerability (percentage of sites with AF induction by single premature extrastimuli), mean AF duration, atrial effective refractory period (ERP), and conduction velocity were compared among these dogs and in unpaced dogs in the absence or presence of treatment with the same agents. Only amiodarone prevented promotion of AF duration and vulnerability by atrial tachycardia. Furthermore, only amiodarone eliminated tachycardia-induced ERP abbreviation and loss of ERP rate adaptation while obviating L-type Ca 2ϩ -current ␣ 1c -subunit downregulation as determined by Western blot. In an additional series of dogs monitored with repeated electrophysiological studies, amiodarone administered after the induction of atrial tachycardia remodeling reversed remodeling within several days, despite continued atrial tachypacing during amiodarone therapy. Conclusions-Amiodarone is uniquely effective against AF promotion by atrial tachycardia remodeling in this experimental model and prevents electrophysiological and biochemical consequences of remodeling. Amiodarone also reversed remodeling established by 4 days of atrial tachycardia. The inhibition of atrial tachycardia remodeling may therefore contribute to the superior efficacy of amiodarone in

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“…Most studies about electrical atrial remodeling in humans have assessed subjects with and without overt cardiovascular disease [23][24][25]27 . Although micro structural atrial changes have been observed in lone AF 29 , gross and ultra-structural anatomic changes due to underlying cardiac disease, such as fibrosis, may persist indefinitely, despite the restoration to sinus rhythm and may be responsible for persistent electrophysiological abnormalities.…”

Section: Discussionmentioning

confidence: 99%

“…On the other hand, a remarkable vulnerability to recurrence during post-cardioversion period has been observed while reverse remodeling is yet incomplete 23 . However, the necessary time to completely restore atrial electrophysiological properties, especially the conduction velocity, is yet to be defined.The methods employed for electrophysiological analysis are usually invasive [23][24][25]27 and make consecutive analysis of the same subject difficult, generating limitations to determine the moment of complete reversal remodeling. Furthermore, little is known about the effects of antiarrhythmic drugs on the remodeling process, especially amiodarone, frequently used in order to facilitate cardioversion and maintain sinus rhythm 28 .…”

mentioning

confidence: 99%

Remodelagem atrial elétrica reversa após cardioversão de fibrilação atrial isolada de longa duração

Barbosa¹,

Benchimol-Barbosa²,

Bomfim³

et al. 2009

Arq. Bras. Cardiol.

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Background: Atrial fibrillation (AF) itself promotes electrophysiological changes, termed "electrical remodeling", facilitating its recurrence and maintenance. There is evidence that the remodeling process is reversible after restoration of the sinus rhythm (SR). However, the timing for the recovery of electrophysiological properties is still undefined.Objctive: The aim of this study was to assess the atrial electrical activation using P-wave signal-averaged electrocardiogram (P-SAECG) post-cardioversion of long-standing AF, focusing on the reversal remodeling process to identify the timing of the process stabilization.Methods: Subjects with lone persistent AF, eligible for cardioversion and successfully converted to SR, were enrolled at the study. SAECG was performed immediately after reversion to SR and repeated on days seven and thirty.Results: Of 31 subjects, nine presented early recurrence of atrial fibrillation, all of them in the first seven days postcardioversion; 22 remained in SR for at last one month and SAECG was obtained on days seven and thirty after cardioversion. In the latter, P-wave duration progressively abated from the first to the third SAECG (P-wave duration: 185.5±41.9 ms vs 171.7±40.5 ms vs 156.7±34.9 ms, respectively, first, second and third SAECG; p<0.001 for all matches). In the frequency domain analysis, spectral turbulence was not apparent in SAECG immediately postcardioversion, but sharply increased on day seven and remained unchanged on day thirty. Conclusion IntroductionAtrial fibrillation (AF) has been described as a selfperpetuating arrhythmia, which promotes electrophysiological changes in atrial tissue, facilitating its recurrence and maintenance [1][2][3][4][5] . Persistent AF usually progresses to a permanent form and the successful restoration and maintenance of sinus rhythm largely depend on arrhythmia duration, with longstanding AF being more resistant to cardioversion and more prone to recurrence [6][7][8][9] . Both resistance to cardioversion and tendency of recurrence are strongly related to the development of electrophysiological substrates characterized by shortened atrial effective refractory period 2,4,5,[10][11][12][13] , slow conduction in the atrial myocardium 10,11,[14][15][16] and dispersion of refractoriness 4,13,17,18 . These changes can be induced by both rapid atrial pacing and AF itself, and have been termed "electrical remodeling" 2 . The resultant electrophysiological abnormality is the presence of multiple wavelets around the atria, some of which circle back on them creating multiples reentry circuits, as proposed by Moe et al 19,20 in 1962 and 1964, and later confirmed by Allessie et al 21 in 1985.In animal models, the remodeling process has been demonstrated to be reversible after restoration of the sinus rhythm, and is characterized by progressive increase in both atrial conduction velocity and refractoriness (reversal remodeling) 1,2,10,11,13,22 . Recovery has also been demonstrated in human atria 3,[23][24][25][26] . On the other hand, a remarkab...

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Tachycardia-Induced Change of Atrial Refractory Period in Humans

Cited by 141 publications

References 43 publications

Inducibility of atrial fibrillation during electrophysiologic evaluation is associated with increased dispersion of atrial refractoriness

Inducibility of atrial fibrillation during electrophysiologic evaluation is associated with increased dispersion of atrial refractoriness

Effects of Antiarrhythmic Drugs on Fibrillation in the Remodeled Atrium

Remodelagem atrial elétrica reversa após cardioversão de fibrilação atrial isolada de longa duração

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