Some observations on the mechanism of pressure related atrial fibrillation

Sideris, D.A.; Toumanidis, Savvas; Thodorakis, M.; Kostopoulos, Kostis; Tselepatiotis, E.; Langoura, C.; Stringli, T.; Moulopoulos, Spyridon D.

doi:10.1093/oxfordjournals.eurheartj.a060433

Cited by 49 publications

(24 citation statements)

References 2 publications

(3 reference statements)

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“…6,22,24 In a canine model of progressive heart failure, interstitial fibrosis and heterogeneous conduction were considered important determinants of the substrate for AF. 14 In human studies as well, atrial dilatation and impaired conduction were correlated with atrial arrhythmias.…”

Section: Discussionmentioning

confidence: 99%

Development of a Substrate of Atrial Fibrillation During Chronic Atrioventricular Block in the Goat

et al. 2005

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Background-Atrial dilatation is an important risk factor for atrial fibrillation (AF). In the present study, we monitored the electrophysiological changes during progressive atrial dilatation in chronically instrumented goats. Methods and Results-In 8 goats, 2 screw-in leads with piezoelectric crystals were implanted transvenously in the right atrium. After 2 weeks, atrial diameter and effective refractory period were measured. AF paroxysms were induced by burst pacing to determine the baseline AF cycle length and stability of AF. After His-bundle ablation, the above measurements were repeated once a week. After 4 weeks of complete AV block, the free wall of the right atrium was mapped and the atrium was fixed in formalin for histological analysis. After His-bundle ablation, the ventricular rate decreased from 113.8Ϯ4.8 to 44.6Ϯ2.5 bpm. Right atrial diameter increased gradually by 13.5Ϯ3.9% during 4 weeks of AV block (PϽ0.01). The duration of induced AF paroxysms increased from 4.6 seconds to 6.4 minutes (PϽ0.05). Atrial effective refractory period and AF cycle length remained constant. Spontaneous paroxysms of AF were not observed. Atrial mapping during rapid pacing revealed that slow conduction (Ͻ30 cm/s) was present in 3.7Ϯ1.0% of the mapped area (control, 0.9Ϯ0.5%, PϽ0.05). Histological analysis showed hypertrophy without atrial fibrosis. Connexin40 and connexin43 expression was unchanged. Conclusions-Chronic

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Section: Discussionmentioning

confidence: 99%

Development of a Substrate of Atrial Fibrillation During Chronic Atrioventricular Block in the Goat

et al. 2005

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“…[18][19][20] Studies of human atrial electrophysiology performed in the electrophysiology laboratory have focused on RA refractoriness in patients without structural heart disease. These studies demonstrated variable results, including no change in ERP, 7 a reduction in ERP, 8 and an increase in ERP.…”

Section: Acute Atrial Stretch and Conduction Blockmentioning

confidence: 99%

Acute Atrial Stretch Results in Conduction Slowing and Complex Signals at the Pulmonary Vein to Left Atrial Junction

Walters

Lee

Spence

et al. 2014

Circ: Arrhythmia and Electrophysiology

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Background— The pulmonary vein–left atrial (PV–LA) junction is key in pathogenesis of AF, and acute stretch is an important stimulus to AF. We aimed to characterize the response of the junction to acute stretch, hypothesizing that stretch would result in electrophysiological changes predisposing to re-entry. Methods and Results— Fifteen participants undergoing cardiac surgery underwent evaluation of the right superior PV–LA junction using an epicardial mapping plaque. In 10, this was performed before and after atrial stretch imposed by rapid volume expansion, and in 5, it was performed with an intervening observation period. Activation was characterized by conduction slowing and electrogram fractionation transversely across the PV–LA junction, with lines of block also demonstrated perpendicular to the junction. Conduction was decremental (plaque activation time 135.8±46.8 ms with programmed extra stimuli at 10 ms above effective refractory period versus 66.1±22.9 ms with pacing at 400 ms; P <0.001) and percentage fractionation was greater with programmed extra stimuli at 10 ms above (33.5%±15.3% versus 20.7%±14.0%, P =0.001). Right atrial pressure increased by 2.5±1.8 mm Hg ( P =0.002) with volume expansion. Stretch resulted in conduction slowing across the PV–LA junction (increase in activation time 10.9±14.6 ms in acute stretch group versus −0.1±4.5 ms in control group; P =0.002). Conduction slowing was more marked with programmed extra stimuli at 10 ms above effective refractory period than with stable pacing (13.4±16.5 ms versus 1.7±5.4 ms; P =0.003). Stretch resulted in a significant increase in fractionated electrograms (7.9%±7.0% versus −0.4±3.3; P =0.004). Conclusions— Acute stretch results in conduction slowing across the PV–LA junction, with a greater degree of signal complexity. This substrate may be important in AF initiation and maintenance by promoting re-entry.

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“…This can be explained by the preservation of the sinus node integrity when the more recent techniques are used. Also, modifications in the atrial geometry predispose to atrial arrhythmias, as well as to increased internal pressure, since these events prolong the electric conduction time 34,54,55 . An additional risk for arrhytmias are the acute graft rejection episodes 34,56 .…”

Section: Discussionmentioning

confidence: 99%

O transplante cardíaco biatrial deve ainda ser realizado? Metanálise

Locali¹,

Matsuoka²,

Cherbo³

et al. 2010

Arq. Bras. Cardiol.

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.standard, two other techniques -the total and bicaval transplantation, were developed with the aim of ensuring better anatomical and physiological graft adaptation and better postoperative outcomes [5][6][7][8][9] . In fact, there are evidences in the literature that better results are obtained with the two techniques described more recently [10][11][12][13][14][15][16][17][18][19][20][21] . However, these evidences are weak when considered alone, and thus do not ensure an adequate level of evidence, especially because most of them are from retrospective studies with small case series 11,14,[22][23][24][25] .For this reason, in 2007, Schnoor et al 10 conducted a metaanalysis with the purpose of increasing the statistical power of the evidences that the new techniques are better than the biatrial transplantation 10 . However, these authors excluded retrospective studies from the main assessments; they included the two more recent techniques in a single group and made a limited review of the literature. As such, relevant data may have not been included in the meta-analysis, thus making the evidence incomplete. For this reason, the objective of this study was to determine whether the techniques of total and bicaval heart transplantation are better than the biatrial technique, thus adding to Schnoor et al 10 results. Method Inclusion and exclusion criteria Study selectionProspective controlled studies were included, whether randomized or not. Description of the randomization techiques, masking and patient follow-up, as described in the respective methodology of the studies, were not considered as criteria for inclusion. Retrospective studies including control groups were also included.Studies whose designs did not meet these requirements, like case series and uncontrolled retrospective studies, narrative reviews and systematic reviews of the literature, case reports, letters, brief communications, and experimental animal studies were excluded. Additionally, studies whose results were incomplete, that is, those not reporting information on mean and standard deviation for continuous numeric variables and proportion of events occurred for nominal categorical variables, were also excluded. PatientsNo restrictions were made as to patient gender, age, and ethnicity, or as to the baseline heart diseases that led SummaryThe outcomes of total and bicaval heart transplantation techniques are better than those of the biatrial technique; however, the latter is still considered the gold-standard. The objective of this study was to determine whether the total and bicaval heart transplantation techniques are, in fact, better than the biatrial technique. A systematic review with meta-analysis was carried out. Studies were retrieved from Pubmed™, Lilacs™, Web of Science™, Scirus™, Scopus™, Google Scholar™, and Scielo™ databases, identified by sensitive strategy. Randomized, prospective, and retrospective controlled studies were selected for inclusion. Intra and postoperative parameters were assessed. A total of 11,602 studies were ...

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Some observations on the mechanism of pressure related atrial fibrillation

Cited by 49 publications

References 2 publications

Development of a Substrate of Atrial Fibrillation During Chronic Atrioventricular Block in the Goat

Development of a Substrate of Atrial Fibrillation During Chronic Atrioventricular Block in the Goat

Acute Atrial Stretch Results in Conduction Slowing and Complex Signals at the Pulmonary Vein to Left Atrial Junction

O transplante cardíaco biatrial deve ainda ser realizado? Metanálise

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