Role of Left Atrial Appendage in Left Atrial Reservoir Function as Evaluated by Left Atrial Appendage Clamping During Cardiac Surgery

Tabata, Tomotsugu; Oki, Takashi; Yamada, Hirotsugu; Iuchi, Arata; Ito, Susumu; Hori, Takaki; Kitagawa, Tetsuya; Kato, Itsuo; Kitahata, Hiroshi; Oshita, Shuzo

doi:10.1016/s0002-9149(97)00903-x

Cited by 157 publications

(103 citation statements)

References 15 publications

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“…Nagano et al (28) found in normal subjects that the left atrium was less compliant than the left ventricle, facilitating blood transfer between the chambers during the early conduit phase. It is not surprising, however, that others have suggested that increased atrial compliance, which promotes reservoir function (17,37), would have a greater positive impact on cardiac output than would supplementation of conduit function (2,36). Hoit and Gabel (14) examined left atrial mechanics during left ventricular dysfunction, comparing the compensatory response with a normal atrium versus a failing atrium (induced with rapid atrial pacing).…”

Section: Discussionmentioning

confidence: 99%

Reservoir and conduit function of right atrium: impact on right ventricular filling and cardiac output

Gaynor¹,

Maniar²,

Prasad³

et al. 2005

American Journal of Physiology-Heart and Circulatory Physiology

118

106

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The purpose of this study was to investigate the relationship between right atrial (RA) reservoir and conduit function and to determine how hemodynamic changes influence this relationship and its impact on cardiac output. In 11 open-chest sheep, RA reservoir and conduit function were quantified as RA inflow with the tricuspid valve closed versus open, respectively. Conduit function was separated into early (before A wave) and late (after A wave) components. The effects of inotropic stimulation, partial pulmonary artery occlusion, and pericardiotomy were tested. At baseline with the pericardium intact, reservoir function accounted for 0.56 (SD 0.13) of RA inflow, early conduit for 0.29 (SD 0.07), and late conduit (during RA contraction) for 0.16 (SD 0.11). Inotropic stimulation decreased conduit function and increased reservoir function, but these effects did not reach statistical significance. With partial pulmonary artery occlusion, early conduit function fell to 0.20 (SD 0.11) (P Ͻ 0.04), and the conduit-to-reservoir ratio decreased by 41% (P Ͻ 0.03). Similarly, after pericardiotomy, early conduit function fell to 0.14 (SD 0.09) (P Ͻ 0.004), reservoir function increased to 0.72 (SD 0.08) (P Ͻ 0.04), and, consequently, the early conduit-to-reservoir ratio decreased by 63% (P Ͻ 0.006). Cardiac output was inversely related to the conduit-to-reservoir ratio (r ϭ 0.39, P Ͻ 0.001). This study demonstrated that the right atrium adjusts its ability to act more as a reservoir than a conduit in a dynamic manner. The RA conduit-to-reservoir ratio was directly related to the right ventricular pressure-RA pressure gradient at the time of maximum RA volume, with increased ventricular pressures favoring conduit function, but it was inversely related to cardiac output, with an increase in the reservoir contribution favoring improved cardiac output. right atrial function; conductance catheter; right ventricular afterload; inotropic stimulation; pulmonary artery occlusion THE RIGHT ATRIUM is a dynamic structure whose role is to assist filling of the right ventricle. Ideally, the right atrium should transfer a high volume of blood rapidly to the ventricle at low pressure to prevent peripheral edema and hepatic congestion. The three components of atrial function are 1) reservoir function, storing blood when the tricuspid valve is closed and releasing stored blood when it opens; 2) conduit function, passive blood transfer directly from the coronary and systemic veins to the right ventricle when the tricuspid valve is open; and 3) booster pump function, atrial contraction in late diastole to complete ventricular filling (10,13,31). Previous studies have demonstrated that pathologically altered left atrial conduit-to-reservoir function is an important determinant of left heart function and can profoundly affect cardiac performance (2, 4, 14 -17, 30, 33, 34, 38), but studies examining right atrial (RA) reservoir and conduit function are limited.The mechanics of the right atrium are complex (5,8,24,26). In 1628, William Harvey was the...

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Section: Discussionmentioning

confidence: 99%

Reservoir and conduit function of right atrium: impact on right ventricular filling and cardiac output

Gaynor¹,

Maniar²,

Prasad³

et al. 2005

American Journal of Physiology-Heart and Circulatory Physiology

118

106

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“…3 However, the LAA is also the most common site for thrombus formation in atrial fibrillation. 4 The physiological consequences of a congenitally absent LAA are unknown.…”

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confidence: 99%

Congenital Absence of the Left Atrial Appendage

Collier

Cavalcante

Phelan

et al. 2012

Circ: Cardiovascular Imaging

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“…50 In humans, LAA relaxation declines with age, 51 as does the thickness of pectinate muscles. 30 Dog studies of LAA exclusion demonstrate acute reduction in reservoir atrial function and increased restrictive physiology in keeping with loss of the atrial compliance chamber, 52, 53 , findings which are also reflected in patients undergoing surgical LAA closure, 54,55 and with a reduction in atrial booster function by up to a third when the appendage is removed. 56,57 Patients with AF undergoing LARIAT percutaneous LAA ligation (detailed below) have a marked reduction in circulating renin, aldosterone, and noradrenaline levels (unpublished).…”

Section: Functionmentioning

confidence: 99%