Left Atrial Mechanical Adaptation to Long-Standing Hemodynamic Loads Based on Pressure–Volume Relations

doi:10.1016/S0002-9149(98)00134-9

The American Journal of Cardiology

Volume 81, Issue 9, 1 May 1998, Pages 1138-1143

https://doi.org/10.1016/S0002-9149(98)00134-9 Get rights and content

Abstract

Left atrial (LA) adaptation during the development of left ventricular (LV) dysfunction is not fully understood. We performed echocardiographic assessment of LA volumes simultaneously with recordings of pulmonary wedge pressures in 60 patients. Twenty patients had no structural or functional LV abnormalities, 20 had a recent myocardial infarction with LV dysfunction, and 20 suffered from congestive heart failure (CHF). Pressure–volume loops were obtained at baseline and during increases in LA pressure produced by normal saline infusion. LA afterload was estimated by the effective LV elastance (E_LV). Atrioventricular coupling was calculated by the E_LV/E_es ratio (where E_es is the end-systolic elastance). E_es increased in patients with myocardial infarction (0.80 ± 0.09 mm Hg/ml, p <0.001), whereas it decreased in patients with CHF (0.22 ± 0.05 mm Hg/ml, p <0.001) compared with controls (0.61 ± 0.07 mm Hg/ml). Similarly, stroke workload increased in patients with myocardial infarction (60.7 ± 7.3 mm Hg · ml, p <0.001), whereas it decreased in patients with CHF (25.4 ± 2.2 mm Hg · ml, p <0.001) compared with controls (44.8 ± 5.5 mm Hg · ml). In all patients LA stiffness (slope of the relation of the filling portion of the pressure–volume loop) was increased compared with controls (controls: 0.13 ± 0.04, patients with myocardial infarction: 0.22 ± 0.05, and patients with CHF: 0.27 ± 0.05 mm Hg/ml, p <0.001 for both comparisons). Moreover, the E_LV/E_es ratio increased gradually as LV function deteriorated (controls: 1.06 ± 0.10, patients with myocardial infarction: 1.35 ± 0.16, and patients with CHF: 6.90 ± 0.84, p <0.001). Thus, early in heart failure, LA pump function is augmented but LA stiffness increases and work mismatch occurs. With further progression of LV dysfunction, LA pump function decreases as a result of increased afterload imposed on the LA myocardium.

Section snippets

Study Population

The study population consisted of 60 subjects, in whom the LA pressure–volume relation was assessed. The control group consisted of 20 subjects who had chest pain and no evidence of heart disease after complete clinical, electrocardiographic, and echocardiographic examinations and treadmill exercise testing. The patients’ group included 2 subgroups: the myocardial infarction group consisted of 20 patients who had documented anteroseptal transmural myocardial infarction and no other associated

Method Repeatability

Repeatability coefficient values for intraobserver repeatability concerning LA volume and its pulsatile changes were 3.5 and 0.49 ml, respectively. These values were small compared with the mean values of LA volume and its pulsatile changes in this sample (41 and 6 ml, respectively). The same procedure was applied for wedge pressure at the peak of the A wave, stroke workload, end-systolic elastance, V_0,es intercept, and stiffness constant. Repeatability coefficient values for pressure, stroke

Discussion

The main findings of the present study are the following: early during the course of evolving heart failure an initial increase in LA pump function associated with an increase in LA afterload occurs. In these patients with increased atrial systolic function, however, stroke workload is far from optimal due to impaired atrioventricular coupling. In end-stage heart failure, LA pump function is reduced, leading to further impairment of atrioventricular coupling and eventual loss of LA compensation.

Acknowledgements

The contribution of Fani Safeti, RN, to the present study is gratefully acknowledged.

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Reference values of left and right atrial volumes and phasic function based on a large sample of healthy Chinese adults: A cardiovascular magnetic resonance study
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The left and right atrial (LA and RA) size and function are tightly linked to the morbidity and mortality of multiple cardiovascular diseases. We aimed to establish cardiovascular magnetic resonance (CMR) reference values for LA and RA volumes and phasic function based on a large sample of healthy Chinese adults.
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Men demonstrated greater LAVmax, LAVmin, LAVpac, LAPEV, RAVmax, RAVmin, RAVpac, RATEV, and RAAEV, while women had higher LAEF total, LAEF booster, RAEF total, RAEF passive, and RAEF booster (all p < 0.05). Age was positively correlated with LAVpac and RAVpac in both sexes but was positively correlated with LAVmax, LAVmin, RAVmax, and RAVmin only in women (all p < 0.05). For both sexes, aging was associated with decreased LAEF total, LAEF passive, RAEF total, and RAEF passive, but increased LAEF booster (all p < 0.05).
We systematically provide age- and sex-specific CMR reference values for LA and RA volumes and phasic function based on a large sample of healthy Chinese adults with a wide age range. Both age and sex are closely associated with biatrial volumes and function.
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The aim of this study was to assess the effect of congestion and decongestive therapy on left atrial (LA) mechanics and to determine the relationship between LA improvement after decongestive therapy and clinical outcome in immediate or chronic heart failure with reduced ejection fraction (HFrEF).
LA mechanics are affected by volume/pressure overload in decompensated HFrEF.
A total of 31 patients with HFrEF and immediate heart failure (age 64 ± 15 years, 74% male, left ventricular ejection fraction 20 ± 12%) underwent serial echocardiography during decongestive therapy with simultaneous hemodynamic monitoring. LA function was assessed by strain (rate) imaging. Patients were re-evaluated 6 weeks after discharge and prospectively followed up for the composite endpoint of heart failure readmission and all-cause mortality.
LA reservoir function was markedly reduced at baseline and improved with decongestion (peak atrial longitudinal strain from 6.4 ± 2.2% to 8.8 ± 3.0% and strain rate from 0.29 ± 0.11 s^–1 to 0.38 ± 0.13 s^–1), independent of changes in left ventricular global longitudinal strain, LA end-diastolic volume, and mitral regurgitation severity (p < 0.001). Both measures continued to rise at 6 weeks (up to 13.4 ± 6.1% and 0.50 ± 0.19 s^–1, respectively; p < 0.001). LA pump strain rate only increased 6 weeks after discharge (–0.25 ± 0.12 s^–1 to –0.55 ± 0.29 s^–1; p < 0.010). Changes in LA mechanics correlated with changes in wedge pressure (r = –0.61; p < 0.001). Lower peak atrial longitudinal strain values after decongestion were associated with increased risk for the composite endpoint of heart failure and mortality (p < 0.019).
LA reservoir and booster function, while severely impaired during immediate decompensation, significantly improve during and after decongestive therapy. Poor LA reservoir function after decongestion is associated with worse outcome.
Acute Decompensated Heart Failure in Patients with Heart Failure with Preserved Ejection Fraction
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Citation Excerpt :
Tricuspid plane annular systolic excursion (TAPSE) to pulmonary artery systolic pressure (PASP) ratio is a useful, simple, and noninvasive indicator of RV-PC coupling that has arisen in recent years.30–33 On the other hand, the left atrium is extremely sensitive to sustained volume and pressure overload secondary to increased LV filling pressures,34 and the stepwise backward effects of loss in left atrial (LA) functional properties are a reduction in lung vessel compliance and vascular remodeling that may trigger RV overload and dysfunction35 (Fig. 2). In fact, the evolving stages of HFrEF or HFpEF are associated with RV-to-PC uncoupling, gas exchange impairment, and exercise ventilation inefficiency.23,36
Left Atrial Function: Basic Physiology
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A resurgence of interest in atrial function has enhanced our understanding of the atrial contributions to cardiovascular performance in health and disease. Despite this attention, quantifying atrial function is difficult, in part because the atria are geometrically complex and because of the critical interplay between the cardiac cycle-dependent atrial functions and ventricular performance. The primary mechanical function of the left atrium (LA) is to modulate left ventricular filling and cardiovascular performance, a task that is accomplished by its interrelated atrial roles as a reservoir for pulmonary venous flow during ventricular systole, as a conduit for pulmonary venous flow during early ventricular diastole, and as a booster pump that increases ventricular filling during late ventricular diastole. This chapter will discuss these cycle-dependent functions in the context of normal LA physiology, ventricular systolic and diastolic dysfunction, and primary atrial myocardial disease using the LA pressure-volume relation, conventional methods, and deformation analysis.
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Original ArticlesLeft Atrial Mechanical Adaptation to Long-Standing Hemodynamic Loads Based on Pressure–Volume Relations

Abstract

Section snippets

Study Population

Method Repeatability

Discussion

Acknowledgements

Am Heart J

J Am Coll Cardiol

Am J Cardiol

Am J Med

J Am Coll Cardiol

Wall stress and paterns of hypertrophy in human left ventricle

J Clin Invest

Regional changes in hemodynamics and cardiac myocyte size in rats with aortocaval fistulasDeveloping and establishing hypertrophy

Circ Res

Cardiac beta myocin heavy chain diversity in normal and chronically hypertensive baboons

J Clin Invest

Left atrial mechanical and biochemical adaptation to pacing induced heart failure

Cardiovasc Res

Mechanism of altered patterns of left ventricular filling during the development of congestive heart failure

Circulation

Left atrial contribution to ventricular filling during the course of evolving heart failure

Circulation

Original Articles
Left Atrial Mechanical Adaptation to Long-Standing Hemodynamic Loads Based on Pressure–Volume Relations