The diastatic pressure-volume relationship is not the same as the end-diastolic pressure-volume relationship

Zhang, Wei; Kovács, Sándor J.

doi:10.1152/ajpheart.00200.2008

Cited by 28 publications

(27 citation statements)

References 43 publications

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“…Hence the diastatic pressure-volume (P-V) relation can be differentiated from the end-diastolic P-V relation, which is conventionally used to determine LV stiffness. 14 With the earlier discussion as background, and emphasizing that during the cardiac cycle the left heart generates external work (energy source) versus being the recipient of work (energy sink) let us examine the indexes used to characterize LA function-particularly LA diastolic function and dysfunction. …”

mentioning

confidence: 99%

The Role of Left Atrial Function in Diastolic Heart Failure

Appleton¹,

Kovács

2009

Circ: Cardiovascular Imaging

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N ew heart failure affects 500 000 Americans yearly. Nearly 50% of these patients have a normal left ventricular ejection fraction (LVEF) or so-called diastolic heart failure (DHF). New onset symptomatic DHF is a lethal disease with a 5-year mortality that approaches 50%. 1 EchoDoppler techniques use LV filling patterns and tissue Doppler imaging of the mitral annulus to help identify and classify the degree of LV diastolic dysfunction, but work best in symptomatic patients with advanced disease. 2 Therefore, the diagnosis of early diastolic dysfunction, when asymptomatic and most treatable, remains problematic. A detailed causality-based, mechanistic understanding of what causes DHF, and how to most easily detect it, remains one of the most important unsolved problems in cardiovascular physiology and clinical cardiology. 3 Article see p 10Segmental LV deformation analysis for calculating contractile parameters such as strain and strain rate is now possible using noninvasive echo-Doppler techniques. 2 It has been reported that LA systolic and diastolic function can also be assessed using these Doppler strain techniques. 4 -6 Although LA enlargement increases with the severity of diastolic dysfunction, 7 the ability of LA volume measurements to discriminate asymptomatic LV diastolic dysfunction from early DHF heart failure has not been possible. However, the concept that an alteration in LA function or stiffness may indicate this change is appealing. The Present StudyTo that end in this issue Kurt et al 8 seek to advance our knowledge of additional clinical, anatomic and physiological correlates of DHF, with a particular focus on LA "diastolic function" and LA stiffness. They report clinical and echoDoppler data on 64 subjects undergoing right heart catheterization with simultaneous echocardiography, and a control group of 27 control subjects. The 64 subjects included 25 with systolic heart failure (LVEFϽ50%), 20 with DHF and normal LVEF and 19 with LV hypertrophy from hypertension, also with normal LVEF but with no history of DHF. In addition to LV mass and LA volumes they measured LA strain and strain rate during LV systole (LA s ) and LA contraction (LA A ), invasive LA stiffness (pulmonary wedge pressure/LA strain) and noninvasive stiffness as estimated by (E/eЈ)/(LA strain). Their main finding was that although asymptomatic hypertension patients with LVH and patients with normal LVEF and DHF had no differences in LV mass, LA volumes, or LA contractile function, DHF patients did have reduced LA strain and strain rate during LV systole, and an increased LA stiffness index. The analysis included use of receiver operating characteristic curves, and was adequately powered.There is much to be commended in this effort. The incorporation of hemodynamic data are increasingly rare in clinical studies and cannot be adequately replaced by surrogates such as Doppler E/eЈ ratios. The use of cardiac filling pressures with indices of LA function (strain and strain rate) to calculate LA stiffness is novel and worth explorin...

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confidence: 99%

The Role of Left Atrial Function in Diastolic Heart Failure

Appleton¹,

Kovács

2009

Circ: Cardiovascular Imaging

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“…Therefore, when heart rate is sufficiently low, the DPVR must be a more reliable metric of passive LV properties and less influenced by atrial properties than the EDPVR. Data supporting this intuitive argument show that, indeed, EDPVR is distinct from and typically defines a higher stiffness than the DPVR (131). Furthermore, the ED-PVR is identical to the DPVR in the setting of atrial fibrillation, which indicates that the DPVR is an index determined by ventricular stiffness alone (75).…”

Section: Diastasismentioning

confidence: 93%

“…This force balance implies that the chamber volume at diastasis defines the equilibrium volume of the relaxed chamber. More importantly, the beat-to-beat variation of diastatic pressure and volume points can be fit linearly to provide the diastatic pressure-volume relation (DPVR), whose slope (dP/dV) provides passive chamber stiffness (131).…”

Section: Diastasismentioning

confidence: 99%

What global diastolic function is, what it is not, and how to measure it

Chung

Shmuylovich

Kovács

2015

American Journal of Physiology-Heart and Circulatory Physiology

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Leonardo da Vinci's observation (circa 1511) that "the atria or filling chambers contract together while the pumping chambers or ventricles are relaxing and vice versa," the dynamics of four-chamber heart function, and of diastolic function (DF) in particular, are not generally appreciated. We view DF from a global perspective, while characterizing it in terms of causality and clinical relevance. Our models derive from the insight that global DF is ultimately a result of forces generated by elastic recoil, modulated by cross-bridge relaxation, and load. The interaction between recoil and relaxation results in physical wall motion that generates pressure gradients that drive fluid flow, while epicardial wall motion is constrained by the pericardial sac. Traditional DF indexes (, E/E=, etc.) are not derived from causal mechanisms and are interpreted as approximating either stiffness or relaxation, but not both, thereby limiting the accuracy of DF quantification. Our derived kinematic models of isovolumic relaxation and suction-initiated filling are extensively validated, quantify the balance between stiffness and relaxation, and provide novel mechanistic physiological insight. For example, causality-based modeling provides load-independent indexes of DF and reveals that both stiffness and relaxation modify traditional DF indexes. The method has revealed that the in vivo left ventricular equilibrium volume occurs at diastasis, predicted novel relationships between filling and wall motion, and quantified causal relationships between ventricular and atrial function. In summary, by using governing physiological principles as a guide, we define what global DF is, what it is not, and how to measure it. diastolic function; echocardiography; hemodynamics; mathematical modeling; suction pump LEFT VENTRICULAR (LV) DIASTOLIC dysfunction is typically reported and indexed as either an increase in myocardial stiffness or a slowing of relaxation (i.e., cross-bridge dissociation). In actuality, diastolic function (DF) is the result of the continuous interaction between the restoring force of elastic recoil and the opposing force generated by cross bridges that have yet to uncouple from the previous systole. The restoring forces seek to lengthen the muscle, while the cross-bridge forces previously acted to shorten the muscle. The simultaneous action of these two opposing forces during both isovolumic relaxation (IVR) and filling result in wall motion, constrained by pericardial sac volume, and simultaneous generation of pressure gradients. This review discusses the governing physical laws and the constraints of DF, as well as which indexes of DF are consistent with diastolic physiology. Deriving and evaluating indexes of DF using this conceptual framework both clarifies and advances our understanding of DF and diastolic dysfunction in health and disease. Physiology of DiastoleCardiovascular physiology is taught using the Wiggers diagram, which segments the cardiac cycle into systole and diastole ( Fig. 1) (49, 124). Systole begins...

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“…The tourniquets around the venae cavae and the catheters were tunneled, and the sternum was loosely approximated. The conductance catheters were connected to two signal conditioner processors (Sigma 5DF; CD Leycom, Zoetermeer, The Netherlands) to convert instantaneous conductance measurements into relative RA and LA volume as described previously and summarized below (11,21,27,31,36,38). At the conclusion of the study, the animals were killed, and accurate positioning of the conductance catheters was confirmed.…”

Section: Surgical Preparationmentioning

confidence: 99%

“…In general, the diastolic pressure-volume curve is quite linear when analyzed within the physiological range as long as the volume change is small enough to utilize Taylor expansion (38). However, across the entire spectrum of pressures, the relationship is more accurately represented with the nonlinear, exponential equation: P ϭ ␣ ϫ e ␤V ϩ c, where ␣, ␤, and c are the fitted coefficients and compliance is quantified as 1/␤ (ml/mmHg).…”

Section: Data Analysesmentioning

confidence: 99%

Differential impact of short periods of rapid atrial pacing on left and right atrial mechanical function

Weimar

Watanabe

Kazui

et al. 2012

American Journal of Physiology-Heart and Circulatory Physiology

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Current techniques to describe atrial function are limited by their load dependency and hence do not accurately reflect intrinsic mechanical properties. To assess the impact of atrial fibrillation on atrial function, combined pressure-volume relationships (PVR) measured by conductance catheters were used to evaluate the right (RA) and left (LA) atrium in 12 isoflurane-anesthetized pigs. Biatrial PVR were recorded over a wide range of volumes during transient caval occlusion at baseline sinus rhythm (SR), after onset of rapid atrial pacing (RAP), after 1 h of RAP, after conversion to SR, and after 1 h of recovery. Cardiac output decreased by 16% (P ϭ 0.008) with onset of RAP. Mean LA and RA pressures increased by 21 and 40% (P Ͻ 0.001), respectively, and remained elevated during the entire recovery period. RA reservoir function increased from 51 to 58% and significantly dropped to 43% after resumption of SR (P ϭ 0.017). Immediately after RAP, a right shift of LA end-systolic PVR-intercept for endsystolic volume required to generate an atrial end-systolic pressure of 10 mmHg (24.4 Ϯ 4.9 to 28.1 Ϯ 5.2 ml, P ϭ 0.005) indicated impaired contractility compared with baseline. Active LA emptying fraction dropped from 17.6 Ϯ 7.5 to 11.7 Ϯ 3.7% (P Ͻ 0.001), LA stroke volume and ⌬P/⌬t max/P declined by 22% (P ϭ 0.038 and 0.026, respectively), while there was only a trend to impaired RA systolic function. Stiffness quantified by the ratio of pressure to volume at end-diastole was increased immediately after RAP only in the RA (P ϭ 0.020), but end-diastolic PVR shifted rightward in both atria (P ϭ 0.011 LA, P ϭ 0.045 RA). These data suggest that even short periods of RAP have a differential impact on RA and LA function, which was sustained for 1 h after conversion to SR. arrhythmia; atrium; contractility; pressure; tachyarrhythmias ABNORMALITIES OF ATRIAL PERFORMANCE are clinically relevant and are present in many pathological conditions of the heart. Atrial fibrillation (AF) is the most common sustained arrhythmia worldwide with an increase in our aging population (19). It results in a loss of booster pump function in the atrium, which might contribute to the significant morbidity and mortality secondary to hemodynamic compromise and tachycardiainduced cardiomyopathy in some patients. Due to this fact, most attention has been given to the impaired left atrial (LA) contractility during AF (24, 28). However, atrial diseases in which LA compliance is markedly reduced are associated with impaired LA filling while increase in diastolic stiffness resulting in increased LA pressure can maintain stroke volume in the absence of atrial booster pump function, indicating that the changes in mechanical atrial function during AF might be much more complex (5,22).Many previous studies focused on the evaluation of atrial function after the treatment of AF, including catheter ablation or surgery, and revealed a decremental effect of variable degrees of those procedures (7, 29). The Cox-Maze procedure (CMP) was introduced for the surgical tr...

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The diastatic pressure-volume relationship is not the same as the end-diastolic pressure-volume relationship

Cited by 28 publications

References 43 publications

The Role of Left Atrial Function in Diastolic Heart Failure

The Role of Left Atrial Function in Diastolic Heart Failure

What global diastolic function is, what it is not, and how to measure it

Differential impact of short periods of rapid atrial pacing on left and right atrial mechanical function

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