Altered left atrial compliance after atrial appendectomy. Influence on left atrial and ventricular filling.

Hoit, Brian D.; Shao, Yanfu; Tsai, Liang Miin; Patel, Rashmi; Gabel, Marjorie; Walsh, Richard A.

doi:10.1161/01.res.72.1.167

Cited by 151 publications

(97 citation statements)

References 23 publications

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“…The positive impact of enhanced atrial compliance and maintained reservoir to conduit properties on global cardiac performance has previously been reported for the LA (4,11,12,14). In an elegant computer model, Suga (27) also suggested that increased atrial distensibility would improve cardiac performance and concluded that a "flexible atrium" (increased receptacle capabilities) could substantially impact the heart's output.…”

Section: Discussionmentioning

confidence: 68%

Interatrial shunt for chronic pulmonary hypertension: differential impact of low-flow vs. high-flow shunting

Zierer

Melby

Voeller

et al. 2009

American Journal of Physiology-Heart and Circulatory Physiology

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Zierer A, Melby SJ, Voeller RK, Moon MR. Interatrial shunt for chronic pulmonary hypertension: differential impact of low-flow vs. high-flow shunting. Am J Physiol Heart Circ Physiol 296: H639-H644, 2009. First published January 9, 2009 doi:10.1152/ajpheart.00496.2008The purpose of the present study was to determine for the first time the qualitative and quantitative impact of varying degrees of interatrial shunting on right heart dynamics and systemic perfusion in subjects with chronic pulmonary hypertension (CPH). Eight dogs underwent 3 mo of progressive pulmonary artery banding, following which right atrial and ventricular end-systolic and end-diastolic pressure-volume relations were calculated using conductance catheters. An 8-mm shunt prosthesis was inserted between the superior vena cava and left atrium, yielding a controlled model of atrial septostomy. Data were obtained 1) preshunt or "CPH"; 2) "Low-Flow" shunt; and 3) "HighFlow" shunt (occluding superior vena cava forcing all flow through the shunt). With progressive shunting, right ventricular pressure fell from 72 Ϯ 19 mmHg (CPH) to 54 Ϯ 17 mmHg (Low-Flow) and 47 Ϯ 17 mmHg (High-Flow) (P Ͻ 0.001). Cardiac output increased from 1.5 Ϯ 0.3 l/min at CPH to 1.8 Ϯ 0.4 l/min at Low-Flow (286 Ϯ 105 ml/min, 15% of cardiac output; P Ͻ 0.001), but returned to 1.6 Ϯ 0.3 l/min at High-Flow (466 Ϯ 172 ml/min, 29% of cardiac output; P ϭ 0.008 vs. Low-Flow, P ϭ 0.21 vs. CPH). There was a modest rise in systemic oxygen delivery from 252 Ϯ 46 ml/min at CPH to 276 Ϯ 50 ml/min at Low-Flow (P ϭ 0.07), but substantial fall to 222 Ϯ 50 ml/min at High-Flow (P ϭ 0.005 vs. CPH, P Ͻ 0.001 vs. Low-Flow). With progressive shunting, bichamber contractility did not change (P ϭ 0.98), but the slope of the right atrial end-diastolic pressure volume relation decreased (P Ͻ 0.04), consistent with improved compliance. This study demonstrated that Low-Flow interatrial shunting consistently improved right atrial mechanics and systemic perfusion in subjects with CPH, while High-Flow exceeded an "ideal shunt fraction". right heart failure; atrial septostomy right ventricular overload ATRIAL SEPTOSTOMY HAS BEEN employed as a high-risk therapeutic option for patients with chronic pulmonary hypertension (CPH) refractory to maximum medical therapy (7, 16 -18, 21, 22, 25); however, results are often unpredictable, due to a lack of understanding of the qualitative and quantitative impact of varying degrees of acute and chronic atrial shunting on cardiac output and peripheral perfusion. A fine balance likely exists between increased left heart throughput and systemic arterial desaturation following atrial septostomy, such that a defect that is too small will not increase cardiac output sufficiently to impact oxygen delivery, while a defect that is too large will pass a critical level of desaturation, such that systemic oxygen delivery falls. The purpose of the present experimental study was to determine the mechanisms by which interatrial shunting improves systemic perfusion and determine whethe...

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Section: Discussionmentioning

confidence: 68%

Interatrial shunt for chronic pulmonary hypertension: differential impact of low-flow vs. high-flow shunting

Zierer

Melby

Voeller

et al. 2009

American Journal of Physiology-Heart and Circulatory Physiology

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“…Reservoir and conduit functions of the right atrium were calculated by integrating RA inflow (combined SVC and IVC flow) during RV systole (reservoir) and RV diastole (conduit) (16,17,30). Because the tricuspid valve is closed during RV systole, all blood that enters from the cavae during this period is reserved in the atrium (coronary sinus return was temporarily interrupted during data collection).…”

Section: Methodsmentioning

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

117

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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“…The significance of the LAA in fluid balance has been reinforced in humans after clamping of the LAA during cardiac surgery yielded increased LA and left ventricular filling pressures [8]. Animal studies have also shown that by removing the LAA, reduction of both LA compliance and LA function occurs [11]. Notably, a dramatic reduction in cardiac output, of nearly 50%, was witnessed in guinea pigs following ligation of the LAA.…”

Section: Laa Physiologymentioning

confidence: 99%

The Left Atrial Appendage in Health and Disease

Howlett¹

2015

MOJAP

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Atrial fibrillation (AF) is the commonest sustained cardiac arrhythmia and results in significant morbidity and mortality. The left atrial appendage (LAA), a small embryonic remnant of the left atrium (LA), has been shown to play a key role in the pathophysiology of AF-related stroke and thromboembolism. As a consequence the LAA, in spite of its meagre size, has been described as 'our most lethal human attachment'. Despite being a recognised harbinger of disease, the LAA has also been shown to play an important role in health. This review seeks to address our current understanding of this vital structure in both health and disease states.

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Altered left atrial compliance after atrial appendectomy. Influence on left atrial and ventricular filling.

Cited by 151 publications

References 23 publications

Interatrial shunt for chronic pulmonary hypertension: differential impact of low-flow vs. high-flow shunting

Interatrial shunt for chronic pulmonary hypertension: differential impact of low-flow vs. high-flow shunting

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

The Left Atrial Appendage in Health and Disease

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