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Gao M, Moslehpour M, Olivier NB, Mukkamala R. Emax monitoring by aortic pressure waveform analysis. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2015; 2014:6762-5. [PMID: 25571548 DOI: 10.1109/embc.2014.6945180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Emax- the maximal left ventricular elastance- is perhaps the best available scalar index of contractility. However, the conventional method for its measurement involves obtaining multiple ventricular pressure-volume loops at different loading conditions and is thus impractical. We previously proposed a more practical technique for tracking Emax from just a single beat of an aortic pressure waveform based on a lumped parameter model of the left ventricle and arteries. Here, we tested the technique against the conventional Emax measurement method in animals during inotropic interventions. Our results show that the estimated Emax changes corresponded fairly well to the reference changes, with a correlation coefficient of 0.793. With further development and testing, the technique could ultimately permit continuous and less invasive monitoring of Emax.
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Abi-Abdallah Rodriguez D, Durand E, de Rochefort L, Boudjemline Y, Mousseaux E. Simultaneous pressure-volume measurements using optical sensors and MRI for left ventricle function assessment during animal experiment. Med Eng Phys 2014; 37:100-8. [PMID: 25500196 DOI: 10.1016/j.medengphy.2014.11.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Revised: 10/15/2014] [Accepted: 11/16/2014] [Indexed: 12/22/2022]
Abstract
Simultaneous pressure and volume measurements enable the extraction of valuable parameters for left ventricle function assessment. Cardiac MR has proven to be the most accurate method for volume estimation. Nonetheless, measuring pressure simultaneously during MRI acquisitions remains a challenge given the magnetic nature of the widely used pressure transducers. In this study we show the feasibility of simultaneous in vivo pressure-volume acquisitions with MRI using optical pressure sensors. Pressure-volume loops were calculated while inducing three inotropic states in a sheep and functional indices were extracted, using single beat loops, to characterize systolic and diastolic performance. Functional indices evolved as expected in response to positive inotropic stimuli. The end-systolic elastance, representing the contractility index, the diastolic myocardium compliance, and the cardiac work efficiency all increased when inducing inotropic state enhancement. The association of MRI and optical pressure sensors within the left ventricle successfully enabled pressure-volume loop analysis after having respective data simultaneously recorded during the experimentation without the need to move the animal between each inotropic state.
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Affiliation(s)
| | - Emmanuel Durand
- Univ Paris-Sud, IR4M, UMR8081 Orsay, France; CNRS, IR4M, UMR8081 Orsay, France
| | | | - Younes Boudjemline
- Univ Paris 05, France; Hôpital Necker-Enfants malades, AP HP, Paris, France
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Tan W, Madhavan K, Hunter KS, Park D, Stenmark KR. Vascular stiffening in pulmonary hypertension: cause or consequence? (2013 Grover Conference series). Pulm Circ 2014; 4:560-80. [PMID: 25610594 PMCID: PMC4278618 DOI: 10.1086/677370] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Accepted: 05/27/2014] [Indexed: 12/24/2022] Open
Abstract
Recent studies have indicated that systemic arterial stiffening is a precursor to hypertension and that hypertension, in turn, can perpetuate arterial stiffening. Pulmonary artery (PA) stiffening is also well documented to occur in pulmonary hypertension (PH), and there is evidence that pulmonary vascular stiffness (PVS) may be a better predictor of outcome than pulmonary vascular resistance (PVR). We have hypothesized that the decreased flow-damping function of elastic PAs in PH likely initiates and/or perpetuates dysfunction of pulmonary microvasculature. Recent studies have shown that large-vessel stiffening increases flow pulsatility in the distal pulmonary vasculature, leading to endothelial dysfunction within a proinflammatory, vasoconstricting, and profibrogenic environment. The intricate role of stiffening-stimulated high pulsatile flow in endothelial cell dysfunction includes stepwise molecular events underlying PA hypertrophy, inflammation, endothelial-mesenchymal transition, and fibrosis. In addition to contributing to microenvironmental alterations of the distal vasculature, disordered proximal-distal PA coupling likely also plays a role in increasing ventricular afterload, ultimately causing right ventricle (RV) dysfunction and death. Current therapeutic treatments do not provide a realistic approach to destiffening arteries and, thus, to potentially abrogating the effects of high pulsatile flow on the distal pulmonary vasculature or the increased work imposed by stiffening on the RV. Scrutinizing the effect of PA stiffening on high pulsatile flow-induced cellular and molecular changes, and vice versa, might lead to important new therapeutic options that abrogate PA remodeling and PH development. With a clear understanding that PA stiffening may contribute to the progression of PH to an irreversible state by contributing to chronic microvascular damage in lungs, future studies should be aimed first at defining the underlying mechanisms leading to PA stiffening and then at improved treatment approaches based on these findings.
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Affiliation(s)
- Wei Tan
- Department of Pediatrics, University of Colorado Denver, Aurora, Colorado, USA
- Cardiovascular Pulmonary Research Laboratories, University of Colorado Denver, Aurora, Colorado, USA
- Department of Mechanical Engineering, University of Colorado Boulder, Boulder, Colorado, USA
| | - Krishna Madhavan
- Department of Pediatrics, University of Colorado Denver, Aurora, Colorado, USA
- Department of Bioengineering, University of Colorado Denver, Aurora, Colorado, USA
| | - Kendall S. Hunter
- Department of Pediatrics, University of Colorado Denver, Aurora, Colorado, USA
- Department of Bioengineering, University of Colorado Denver, Aurora, Colorado, USA
| | - Daewon Park
- Department of Bioengineering, University of Colorado Denver, Aurora, Colorado, USA
| | - Kurt R. Stenmark
- Department of Pediatrics, University of Colorado Denver, Aurora, Colorado, USA
- Cardiovascular Pulmonary Research Laboratories, University of Colorado Denver, Aurora, Colorado, USA
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Wang CH, Wu ET, Wu MS, Tsai MS, Ko YH, Chang RW, Chang CY, Chang KC. Pyridoxamine protects against mechanical defects in cardiac ageing in rats: studies on load dependence of myocardial relaxation. Exp Physiol 2014; 99:1488-98. [PMID: 25239923 PMCID: PMC4240468 DOI: 10.1113/expphysiol.2014.082008] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
New Findings Our team demonstrated in the past that pyridoxamine attenuated arterial stiffening by targeting the pathogenic formation of glycated collagen cross-links in aged rats. Herein, we examined whether pyridoxamine therapy can protect against mechanical defects in myocardial relaxation by improving arterial wave properties and cardiac contractile performance in senescent animals. Fifteen-month-old male Fisher 344 rats were treated daily with pyridoxamine (1 g l−1 in drinking water) for 5 months and compared with age-matched untreated control animals (20 months old). Arterial wave properties were characterized by wave transit time (τw) and wave reflection factor (Rf). We measured the contractile status of the myocardium in an intact heart as the left ventricular (LV) end-systolic elastance (Ees). Myocardial relaxation was described according to the time constant of the LV isovolumic pressure decay (τe). Pyridoxamine therapy prevented the age-associated prolongation in LV τe and the diminished Ees in senescent rats. The drug also attenuated the age-related augmentation in afterload imposed on the heart, as evidenced by the increased τw and decreased Rf. We found that the LV τe was significantly influenced by both the arterial τw and Rf (τe = 16.3902 + 8.3123 × Rf − 0.4739 × τw; r = 0.7048, P < 0.005). In the meantime, the LV τe and the LV Ees showed a significant inverse linear correlation (τe = 13.9807 − 0.0068 × Ees; r = 0.6451, P < 0.0005). All these findings suggested that long-term treatment with pyridoxamine might ameliorate myocardial relaxation rate, at least partly through its ability to enhance myocardial contractile performance, increase wave transit time and decrease wave reflection factor in aged rats.
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Affiliation(s)
- Chih-Hsien Wang
- Department of Surgery, National Taiwan University Hospital, Taipei, Taiwan Department of Surgery, Hsin-Chu Branch of National Taiwan University Hospital, Hsin-Chu, Taiwan
| | - En-Ting Wu
- Department of Pediatrics, National Taiwan University Hospital, Taipei, Taiwan
| | - Ming-Shiou Wu
- Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan
| | | | - Ya-Hui Ko
- Department of Physiology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Ru-Wen Chang
- Department of Physiology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Chun-Yi Chang
- Department of Emergency Medicine, National Taiwan University Hospital, Taipei, Taiwan
| | - Kuo-Chu Chang
- Department of Physiology, College of Medicine, National Taiwan University, Taipei, Taiwan
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Guarracino F, Ferro B, Morelli A, Bertini P, Baldassarri R, Pinsky MR. Ventriculoarterial decoupling in human septic shock. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2014; 18:R80. [PMID: 24762124 PMCID: PMC4056562 DOI: 10.1186/cc13842] [Citation(s) in RCA: 85] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/23/2013] [Accepted: 04/03/2014] [Indexed: 12/20/2022]
Abstract
Introduction Septic shock is the most severe manifestation of sepsis. It is characterized as a hypotensive cardiovascular state associated with multiorgan dysfunction and metabolic disturbances. Management of septic shock is targeted at preserving adequate organ perfusion pressure without precipitating pulmonary edema or massive volume overload. Cardiac dysfunction often occurs in septic shock patients and can significantly affect outcomes. One physiologic approach to detect the interaction between the heart and the circulation when both are affected is to examine ventriculoarterial coupling, which is defined by the ratio of arterial elastance (Ea) to left ventricular end-systolic elastance (Ees). In this study, we analyzed ventriculoarterial coupling in a cohort of patients admitted to ICUs who presented with vs without septic shock. Methods In this retrospective cross-sectional opportunity study, we measured routine hemodynamics using indwelling arterial and pulmonary arterial catheters and transthoracic echocardiograms in 25 septic patients (group S) and 25 non–septic shock patients (group C) upon ICU admission. Ees was measured by echocardiography using a single-beat (EesSB) method. Ea was calculated as 0.9 systolic arterial pressure/stroke volume, and then the Ea/EesSB ratio was calculated (normal value <1.36). Results In group S, 21 patients had an Ea/EesSB ratio >1.36 (uncoupled). The four patients with Ea/EesSB ratios ≤1.36 had higher EesSB values than patients with Ea/EesSB ratios >1.36 (P = 0.007), although Ea measurements were similar in both groups (P = 0.4). In group C, five patients had uncoupled Ea/EesSB ratios. No correlation was found between EesSB and left ventricular ejection fraction and between Ea/EesSB ratio and mixed venous oxygen saturation in septic shock patients. Conclusions Upon admission to the ICU, patients in septic shock often display significant ventriculoarterial decoupling that is associated with impaired left ventricular performance. Because Ea/Ees decoupling alters cardiovascular efficiency and cardiac energetic requirements independently of Ea or Ees, we speculate that septic patients with ventriculoarterial uncoupling may benefit from therapy aimed at normalizing the Ea/Ees ratio.
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Pressure-overload-induced right heart failure. Pflugers Arch 2014; 466:1055-63. [PMID: 24488007 DOI: 10.1007/s00424-014-1450-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2014] [Accepted: 01/13/2014] [Indexed: 01/27/2023]
Abstract
Although pulmonary arterial hypertension originates in the lung and is caused by progressive remodeling of the small pulmonary arterioles, patients die from the consequences of pressure-overload-induced right heart failure. Prognosis is poor, and currently there are no selective treatments targeting the failing right ventricle. Therefore, it is of utmost importance to obtain more insights into the mechanisms of right ventricular adaptation and the transition toward right heart failure. In this review, we propose that the same adaptive mechanisms, which initially preserve right ventricular systolic function and maintain cardiac output, eventually initiate the transition toward right heart failure.
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Haemodynamics and left ventricular function in heart failure patients: Comparison of awake versus intra-operative conditions. Eur J Heart Fail 2014; 10:467-74. [DOI: 10.1016/j.ejheart.2008.03.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2007] [Revised: 02/27/2008] [Accepted: 03/27/2008] [Indexed: 11/18/2022] Open
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Dimensional reductions of a cardiac model for effective validation and calibration. Biomech Model Mechanobiol 2013; 13:897-914. [DOI: 10.1007/s10237-013-0544-6] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Accepted: 11/27/2013] [Indexed: 10/25/2022]
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Wang CH, Wang SS, Ko WJ, Chen YS, Chang CY, Chang RW, Chang KC. Acetyl-l-carnitine and oxfenicine on cardiac pumping mechanics in streptozotocin-induced diabetes in male Wistar rats. PLoS One 2013; 8:e69977. [PMID: 23922880 PMCID: PMC3724909 DOI: 10.1371/journal.pone.0069977] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2013] [Accepted: 06/14/2013] [Indexed: 11/18/2022] Open
Abstract
INTRODUCTION In the treatment of patients with diabetes, one objective is an improvement of cardiac metabolism to alleviate the left ventricular (LV) function. For this study, we compared the effects of acetyl-l-carnitine (one of the carnitine derivatives) and of oxfenicine (a carnitine palmitoyltransferase-1 inhibitor) on cardiac pumping mechanics in streptozotocin-induced diabetes in male Wistar rats, with a particular focus on the pressure-flow-volume relationship. METHODS Diabetes was induced by a single tail vein injection of 55 mg kg(-1) streptozotocin. The diabetic animals were treated on a daily basis with either acetyl-L-carnitine (1 g L(-1) in drinking water) or oxfenicine (150 mg kg(-1) by oral gavage) for 8 wk. They were also compared with untreated age-matched diabetic controls. LV pressure and ascending aortic flow signals were recorded to calculate the maximal systolic elastance (E max) and the theoretical maximum flow (Q max). Physically, E max reflects the contractility of the myocardium as an intact heart, whereas Q max has an inverse relationship with the LV internal resistance. RESULTS When comparing the diabetic rats with their age-matched controls, the cardiodynamic condition was characterized by a decline in E max associated with the unaltered Q max. Acetyl-l-carnitine (but not oxfenicine) had reduced cardiac levels of malondialdehyde in these insulin-deficient animals. However, treating with acetyl-l-carnitine or oxfenicine resulted in an increase in E max, which suggests that these 2 drugs may protect the contractile status from deteriorating in the diabetic heart. By contrast, Q max showed a significant fall after administration of oxfenicine, but not with acetyl-L-carnitine. The decrease in Q max corresponded to an increase in total vascular resistance when treated with oxfenicine. CONCLUSIONS Acetyl-l-carnitine, but not oxfencine, optimizes the integrative nature of cardiac pumping mechanics by preventing the diabetes-induced deterioration in myocardial intrinsic contractility associated with unaltered LV internal resistance.
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Affiliation(s)
- Chih-Hsien Wang
- Department of Surgery, National Taiwan University Hospital, Taipei, Taiwan
- Department of Physiology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Shoei-Shen Wang
- Department of Surgery, National Taiwan University Hospital, Taipei, Taiwan
| | - Wen-Je Ko
- Department of Surgery and Traumatology, National Taiwan University Hospital, Taipei, Taiwan
| | - Yih-Sharng Chen
- Department of Surgery, National Taiwan University Hospital, Taipei, Taiwan
| | - Chun-Yi Chang
- Department of Emergency Medicine, National Taiwan University Hospital, Taipei, Taiwan
| | - Ru-Wen Chang
- Department of Surgery and Traumatology, National Taiwan University Hospital, Taipei, Taiwan
| | - Kuo-Chu Chang
- Department of Physiology, College of Medicine, National Taiwan University, Taipei, Taiwan
- * E-mail:
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60
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Non-invasively estimated end-systolic elastance in patients with resistant hypertension and type 2 diabetes mellitus. Heart Vessels 2013; 29:375-83. [DOI: 10.1007/s00380-013-0371-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2012] [Accepted: 05/17/2013] [Indexed: 10/26/2022]
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61
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Guarracino F, Ferro B, Baldassarri R, Bertini P, Forfori F, Giannini C, Di Bello V, Petronio AS. Non invasive evaluation of cardiomechanics in patients undergoing MitrClip procedure. Cardiovasc Ultrasound 2013; 11:13. [PMID: 23642140 PMCID: PMC3651274 DOI: 10.1186/1476-7120-11-13] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/19/2013] [Accepted: 04/26/2013] [Indexed: 11/28/2022] Open
Abstract
Background In the last recent years a new percutaneous procedure, the MitraClip, has been validated for the treatment of mitral regurgitation. MitraClip procedure is a promising alternative for patients unsuitable for surgery as it reduces the risk of death related to surgery ensuring a similar result. Few data are present in literature about the variation of hemodynamic parameters and ventricular coupling after Mitraclip implantation. Methods Hemodynamic data of 18 patients enrolled for MitraClip procedure were retrospectively reviewed and analyzed. Echocardiographic measurements were obtained the day before the procedure (T0) and 21 ± 3 days after the procedure (T1), including evaluation of Ejection Fraction, mitral valve regurgitation severity and mechanism, forward Stroke Volume, left atrial volume, estimated systolic pulmonary pressure, non invasive echocardiographic estimation of single beat ventricular elastance (Es(sb)), arterial elastance (Ea) measured as systolic pressure • 0.9/ Stroke Volume, ventricular arterial coupling (Ea/Es(sb) ratio). Data were expressed as median and interquartile range. Measures obtained before and after the procedure were compared using Wilcoxon non parametric test for paired samples. Results Mitraclip procedure was effective in reducing regurgitation. We observed an amelioration of echocardiographic parameters with a reduction of estimated systolic pulmonary pressure (45 to 37,5 p = 0,0002) and left atrial volume (110 to 93 p = 0,0001). Despite a few cases decreasing in ejection fraction (37 to 35 p = 0,035), the maintained ventricular arterial coupling after the procedure (P = 0,67) was associated with an increasing in forward stroke volume (60,3 to 78 p = 0,05). Conclusion MitraClip is effective in reducing mitral valve regurgitation and determines an amelioration of hemodynamic parameters with preservation of ventricular arterial coupling.
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Affiliation(s)
- Fabio Guarracino
- Department of Cardiothoracic Anesthesia and Intensive Care Medicine, Azienda Ospedaliero Universitaria Pisana, Via Paradisa 2, 56123, Italy.
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Darvishi S, Behnam H, Pouladian M, Samiei N. Measuring Left Ventricular Volumes in Two-Dimensional Echocardiography Image Sequence Using Level-set Method for Automatic Detection of End-Diastole and End-systole Frames. Res Cardiovasc Med 2013; 2:39-45. [PMID: 25478488 PMCID: PMC4253755 DOI: 10.5812/cardiovascmed.6397] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2012] [Revised: 02/01/2012] [Accepted: 02/09/2012] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND Identifying End-Diastole (ED) and End-Systole (ES) frames is highly important in the process of evaluating cardiac function and measuring global parameters accurately, such as Ejection Fraction (EF), Cardiac Output (CO) and Stroke Volume. OBJECTIVES The current study aimed to develop a new method based on measuring volume changes in Left Ventricle (LV) during cardiac cycle. MATERIAL AND METHODS For this purpose, the Level Set method was used both in detecting endocardium border and quantifying cardiac function of all frames. RESULTS Demonstrating LV volumes displays ED and ES frames and the volumes used in calculating the required parameters. CONCLUSIONS Since ES and ED frames exist in iso-volumic phases of the cardiac cycle with minimum and maximum values of LV volume signals, such peaks can be utilized in finding related frames.
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Affiliation(s)
- Saeed Darvishi
- Faculty of Biomedical Engineering, Department of Biomedical Engineering, Science and Research Branch, Islamic Azad University, Tehran, IR Iran
- Corresponding author: Saeed Darvishi, Faculty of Biomedical Engineering, Department of Biomedical Engineering, Science and Research Branch, Islamic Azad University, Tehran, IR Iran. Tel.: +98-2144444330, Fax: +98-2144444331, E-mail: s.
| | - Hamid Behnam
- Department of the Electronic Engineering, Iran University of Science and Technology, Tehran, IR Iran
| | - Majid Pouladian
- Department of Biomedical Engineering, Science and Research Branch, Islamic Azad University, Tehran, IR Iran
| | - Niloufar Samiei
- Echocardiography Research Center, Rajaie Cardiovascular Medical and Research Center, Tehran University of Medical Sciences, Tehran, IR Iran
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63
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Accurate assessment of load-independent right ventricular systolic function in patients with pulmonary hypertension. J Heart Lung Transplant 2013; 32:50-5. [DOI: 10.1016/j.healun.2012.09.022] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2012] [Revised: 08/30/2012] [Accepted: 09/14/2012] [Indexed: 11/20/2022] Open
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Morimont P, Lambermont B, Desaive T, Janssen N, Chase G, D'Orio V. Arterial dP/dtmax accurately reflects left ventricular contractility during shock when adequate vascular filling is achieved. BMC Cardiovasc Disord 2012; 12:13. [PMID: 22380679 PMCID: PMC3313844 DOI: 10.1186/1471-2261-12-13] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2011] [Accepted: 03/01/2012] [Indexed: 11/30/2022] Open
Abstract
Background Peak first derivative of femoral artery pressure (arterial dP/dtmax) derived from fluid-filled catheter remains questionable to assess left ventricular (LV) contractility during shock. The aim of this study was to test if arterial dP/dtmax is reliable for assessing LV contractility during various hemodynamic conditions such as endotoxin-induced shock and catecholamine infusion. Methods Ventricular pressure-volume data obtained with a conductance catheter and invasive arterial pressure obtained with a fluid-filled catheter were continuously recorded in 6 anaesthetized and mechanically ventilated pigs. After a stabilization period, endotoxin was infused to induce shock. Catecholamines were transiently administrated during shock. Arterial dP/dtmax was compared to end-systolic elastance (Ees), the gold standard method for assessing LV contractility. Results Endotoxin-induced shock and catecholamine infusion lead to significant variations in LV contractility. Overall, significant correlation (r = 0.51; p < 0.001) but low agreement between the two methods were observed. However, a far better correlation with a good agreement were observed when positive-pressure ventilation induced an arterial pulse pressure variation (PPV) ≤ 11% (r = 0.77; p < 0.001). Conclusion While arterial dP/dtmax and Ees were significantly correlated during various hemodynamic conditions, arterial dP/dtmax was more accurate for assessing LV contractility when adequate vascular filling, defined as PPV ≤ 11%, was achieved.
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Affiliation(s)
- Philippe Morimont
- Medical Intensive Care Unit, Emergency Department, University Hospital of Liège, and Faculty of Sciences, University of Liège, Liège, Belgium.
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Bozkurt B, Bolos M, Deswal A, Ather S, Chan W, Mann DL, Carabello B. New Insights into Mechanisms of Action of Carvedilol Treatment in Chronic Heart Failure Patients—A Matter of Time for Contractility. J Card Fail 2012; 18:183-93. [DOI: 10.1016/j.cardfail.2011.11.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2011] [Revised: 11/26/2011] [Accepted: 11/30/2011] [Indexed: 10/14/2022]
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66
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Abstract
The problem of heart failure with preserved ejection fraction (HFpEF) has recently received much attention. In this study we discuss some relations that connect ejection fraction EF to the parameters describing the end-systolic pressure-volume relation (ESPVR). It is shown that the study of the relation between EF and ESPVR can give some understanding of the problem of HFpEF. An important feature of the present approach is the introduction of the active force of the myocardium (also called isovolumic pressure) in the formalism describing the ESPVR.
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Affiliation(s)
- Rachad M Shoucri
- Department of Mathematics & Computer Science, Royal Military College of Canada, Kingston, ON K7K7B4, Canada.
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Dette H, Melas VB, Pepelyshev A. Optimal designs for estimating the slope of a regression. STATISTICS-ABINGDON 2010. [DOI: 10.1080/02331880903348473] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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68
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Kind T, Faes TJC, Vonk-Noordegraaf A, Westerhof N. Proportional Relations Between Systolic, Diastolic and Mean Pulmonary Artery Pressure are Explained by Vascular Properties. Cardiovasc Eng Technol 2010; 2:15-23. [PMID: 21423331 PMCID: PMC3036810 DOI: 10.1007/s13239-010-0027-1] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2010] [Accepted: 10/22/2010] [Indexed: 12/26/2022]
Abstract
Recently, it was shown that proportional relationships exist between systolic, diastolic and mean pulmonary artery pressure (Psys, Pdia and Pmean) and that they are maintained under various conditions in both health and disease. An arterial-ventricular interaction model was used to study the contribution of model parameters to the ratios Psys/Pmean, and Pdia/Pmean. The heart was modeled by a time-varying elastance function, and the arterial system by a three-element windkessel model consisting of peripheral resistance, Rp, arterial compliance Ca, and pulmonary artery characteristic impedance Z0. Baseline model parameters were estimated in control subjects and compared to values estimated in patients with pulmonary hypertension. Results indicate that experimentally derived ratios Psys/Pmean and Pdia/Pmean could be accurately reproduced using our model (1.59 and 0.61 vs. 1.55 and 0.64, respectively). Sensitivity analysis showed that the (empirical) constancy of Psys/Pmean and Pdia/Pmean was primarily based on the inverse hyperbolic relation between total vascular resistance (RT; calculated as Rp + Z0) and Ca, (i.e. constant RTCa product). Of the cardiac parameters, only heart rate affected the pressure ratios, but the contribution was small. Therefore, we conclude that proportional relations between systolic, diastolic and mean pulmonary artery pressure result from the constancy of RTCa thus from pulmonary arterial properties, with only little influence of heart rate.
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Affiliation(s)
- Taco Kind
- Department of Pulmonary Diseases, Institute for Cardiovascular Research, VU University Medical Center, Amsterdam, The Netherlands
| | - Theo J. C. Faes
- Department of Physics and Medical Technology, Institute for Cardiovascular Research, VU University Medical Center, Amsterdam, The Netherlands
| | - Anton Vonk-Noordegraaf
- Department of Pulmonary Diseases, Institute for Cardiovascular Research, VU University Medical Center, Amsterdam, The Netherlands
| | - Nico Westerhof
- Department of Pulmonary Diseases, Institute for Cardiovascular Research, VU University Medical Center, Amsterdam, The Netherlands
- Department of Physiology, Institute for Cardiovascular Research, VU University Medical Center, Amsterdam, The Netherlands
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Deryck YLJM, Fonck K, DE Baerdemaeker L, Naeije R, Brimioulle S. Differential effects of sevoflurane and propofol anesthesia on left ventricular-arterial coupling in dogs. Acta Anaesthesiol Scand 2010; 54:979-86. [PMID: 20626353 DOI: 10.1111/j.1399-6576.2010.02267.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
BACKGROUND General anesthetics interfere with arterial and ventricular mechanical properties, often altering left ventricular-arterial (LVA) coupling. We hypothesized that sevoflurane and propofol alter LVA coupling by different effects on arterial and ventricular properties. METHODS Experiments were conducted in six anesthetized open-chest dogs for the measurement of left ventricular pressure and aortic pressure and flow. Measurements were performed during anesthesia with 0.5, 1.0 and 1.5 minimum alveolar concentration sevoflurane and 12, 24 and 36 mg/kg/h propofol. LVA coupling was assessed as the ratio of ventricular end-systolic elastance (E(es), measuring ventricular contractility) to effective arterial elastance (E(a), measuring ventricular afterload). The steady component of afterload, arterial tone, was assessed by systemic vascular resistance and arterial pressure-flow curves. The pulsatile component of afterload was assessed by aortic impedance and compliance. RESULTS Sevoflurane decreased aortic pressure and cardiac output more than propofol. Sevoflurane reduced arterial tone, increased arterial stiffness and did not affect wave reflections. It increased E(a), decreased E(es) and reduced LVA coupling. Propofol reduced arterial tone, did not affect arterial stiffness and decreased wave reflections. It did not affect E(a), E(es) or LVA coupling. CONCLUSIONS Sevoflurane increased ventricular afterload and decreased ventricular performance, thereby altering LVA coupling. Propofol did not affect ventricular afterload or ventricular performance, thereby preserving LVA coupling. Thus, propofol preserves LVA coupling in dogs better, and might be a better choice for patients with compromised left ventricular function.
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Affiliation(s)
- Y L J M Deryck
- Laboratory of Physiology, Free University of Brussels, Brussels, Belgium
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Sugai TK, Tanaka A, Yoshizawa M, Shiraishi Y, Yambe T, Nitta SI, Baba A. Estimation of Maximum Ventricular Elastance Under Assistance With a Rotary Blood Pump. Artif Organs 2010; 34:442-6. [DOI: 10.1111/j.1525-1594.2009.00876.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Chen X, Mukkamala R, Sala-Mercado JA, Hammond RL, Ichinose M, Soltani S, O'Leary DS. Dynamic control of maximal ventricular elastance in conscious dogs before and after pacing-induced heart failure. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2010; 2009:5328-31. [PMID: 19963897 DOI: 10.1109/iembs.2009.5332687] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
We identified the transfer functions relating beat-to-beat fluctuations in arterial blood pressure to maximal ventricular elastance (ABP-->E(max)) and beat-to-beat fluctuations in heart rate to E(max) (HR-->E(max)) to characterize the dynamic properties of the arterial ventricular contractility baroreflex and force-frequency relation, respectively, in three conscious dogs before and after pacing-induced heart failure. During the control condition, the average gain value, dominant time constant, and time delay were respectively -0.0374 ml(-1), 12.8 sec, and 2 sec for the ABP-->E(max) transfer function and 0.0137 mmHg/ml-bpm, 1.77 sec, and 0 sec for the HR-->E(max) transfer function. During the heart failure condition, both transfer functions were markedly depressed. These results are consistent with known physiology and previous studies and provide perhaps the first quantitative information on the dynamic control of E(max) during normal closed-loop operation.
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Affiliation(s)
- Xiaoxiao Chen
- Department of Electrical and Computer Engineering, Michigan State University, East Lansing, MI 48824, USA.
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ten Brinke EA, Klautz RJ, Verwey HF, van der Wall EE, Dion RA, Steendijk P. Single-beat estimation of the left ventricular end-systolic pressure-volume relationship in patients with heart failure. Acta Physiol (Oxf) 2010; 198:37-46. [PMID: 19735484 DOI: 10.1111/j.1748-1716.2009.02040.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
AIM The end-systolic pressure-volume relationship (ESPVR) constructed from multiple pressure-volume (PV) loops acquired during load intervention is an established method to asses left ventricular (LV) contractility. We tested the accuracy of simplified single-beat (SB) ESPVR estimation in patients with severe heart failure. METHODS Nineteen heart failure patients (NYHA III-IV) scheduled for surgical ventricular restoration and/or restrictive mitral annuloplasty and 12 patients with normal LV function scheduled for coronary artery bypass grafting were included. PV signals were obtained before and after cardiac surgery by pressure-conductance catheters and gradual pre-load reductions by vena cava occlusion (VCO). The SB method was applied to the first beat of the VCO run. Accuracy was quantified by the root-mean-square-error (RMSE) between ESPVR(SB) and gold-standard ESPVR(VCO). In addition, we compared slopes (E(ES)) and intercepts (end-systolic volume at multiple pressure levels (70-100 mmHg: ESV(70)-ESV(100)) of ESPVR(SB) vs. ESPVR(VCO) by Bland-Altman analyses. RESULTS RMSE was 1.7 + or - 1.0 mmHg and was not significantly different between groups and not dependent on end-diastolic volume, indicating equal, high accuracy over a wide volume range. SB-predicted E(ES) had a bias of -0.39 mmHg mL(-1) and limits of agreement (LoA) -2.0 to +1.2 mmHg mL(-1). SB-predicted ESVs at each pressure level showed small bias (range: -10.8 to +9.4 mL) and narrow LoA. Two-way anova indicated that differences between groups were not dependent on the method. CONCLUSION Our findings, obtained in hearts spanning a wide range of sizes and conditions, support the use of the SB method. This method ultimately facilitates less invasive ESPVR estimation, particularly when coupled with emerging noninvasive techniques to measure LV pressures and volumes.
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Affiliation(s)
- E A ten Brinke
- Department of Cardiology, Leiden University Medical Center, Leiden, the Netherlands
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Abstract
Enhanced external counterpulsation (EECP) is a noninvasive technique that provides beneficial effects for patients with chronic, symptomatic angina pectoris. However, the direct left ventricular effects of EECP have not been studied invasively. We examined invasive right atrial pressure and left ventricular hemodynamics during EECP. Ten patients referred for diagnostic evaluation underwent left heart catheterization from the radial artery. At baseline and during EECP, left ventricular pressure and volume were measured using a micromanometer pressure-conductance catheter, along with recording of right atrial and central aortic pressures. Hemodynamics were recorded at different lower extremity cuff configuration and cuff inflation pressures. As cuff inflation pressure increased, EECP resulted in a dose-dependent increase in right atrial and aortic diastolic pressure (P < 0.0001). The increase in ventricular preload resulted in increased left ventricular volume. Maximum positive (P = 0.0003) and negative left ventricular dP/dt (P < 0.0001) increased. Left ventricular diastolic pressure decreased. There was a neutral effect on myocardial mechanical efficiency. In conclusion, EECP acutely increased right atrial and central aortic diastolic pressure. The increase in preload attenuated the reduction in left ventricular diastolic pressure resulting from systolic unloading. The increased preload counterbalanced the afterload reduction, resulting in a neutral effect on myocardial efficiency.
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Zanon F, Aggio S, Baracca E, Pastore G, Corbucci G, Boaretto G, Braggion G, Piergentili C, Rigatelli G, Roncon L. Ventricular-arterial coupling in patients with heart failure treated with cardiac resynchronization therapy: may we predict the long-term clinical response? EUROPEAN JOURNAL OF ECHOCARDIOGRAPHY 2009; 10:106-11. [DOI: 10.1093/ejechocard/jen184] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Cheng HM, Yu WC, Sung SH, Wang KL, Chuang SY, Chen CH. Usefulness of systolic time intervals in the identification of abnormal ventriculo-arterial coupling in stable heart failure patients. Eur J Heart Fail 2008; 10:1192-200. [PMID: 19004668 DOI: 10.1016/j.ejheart.2008.09.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/13/2007] [Revised: 06/01/2008] [Accepted: 09/08/2008] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND The ratio of effective arterial elastance (Ea) to ventricular end-systolic elastance (Ees) indicates the status of ventriculo-arterial coupling. AIMS We investigated if systolic time intervals (pre-ejection period, PEP; ejection time, ET; and their ratio, PEP/ET) can be used to identify heart failure patients with abnormal ventriculo-arterial coupling. METHODS Age and sex-matched study subjects included 54 apparently healthy subjects with normal left ventricular (LV) function, and stable patients with LV diastolic (n=54) and systolic dysfunction (n=54). Ees and Ea were estimated non-invasively by echocardiography, and abnormal ventriculo-arterial coupling was defined as Ea/Ees>1.2. PEP, ET, and PEP/ET were measured automatically using electrocardiography, phonocardiography, and brachial pulse volume recording. RESULTS Ea/Ees>1.2 was present in 48.1% of subjects with systolic dysfunction. The PEP/ET was significantly associated with most parameters of LV structure and function, and Ea/Ees (r=0.67, p<0.001). Using PEP/ET> or =0.423 as cut point, the sensitivity and specificity to identify patients with Ea/Ees>1.2 were 85.7% and 84.3%, respectively for the whole population, and 84.6% and 78.6%, for patients with systolic dysfunction. CONCLUSION Abnormal ventriculo-arterial coupling was present in almost half of stable patients with systolic dysfunction. PEP/ET was useful in identifying such patients.
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Mynard J, Penny D, Smolich J. Accurate Automatic Detection of End-Diastole From Left Ventricular Pressure Using Peak Curvature. IEEE Trans Biomed Eng 2008; 55:2651-7. [DOI: 10.1109/tbme.2008.2001295] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Ramcharitar S, Meliga E, Kirschbaum SW, ten Cate FJ, van Geuns RJ, Serruys PW. Acute hemodynamic changes in percutaneous transluminal septal coil embolization for hypertrophic obstructive cardiomyopathy. ACTA ACUST UNITED AC 2008; 5:806-10. [PMID: 18838967 DOI: 10.1038/ncpcardio1355] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2008] [Accepted: 06/27/2008] [Indexed: 11/09/2022]
Abstract
BACKGROUND A 48-year-old man with hypertrophic obstructive cardiomyopathy (HOCM) presented with palpitations, symptoms of medically refractory class II angina, and NYHA class II-III heart failure. INVESTIGATIONS Physical examination revealed a grade 3 systolic murmur that increased to grade 4 with exercise. Echocardiography showed marked septal thickening (17 mm), a left ventricular outflow tract gradient (LVOTG) of 95 mmHg, and a 3+ systolic anterior motion of the mitral valve apparatus. No other pathology was noted with cardiac MRI or with coronary angiography. DIAGNOSIS Severe symptomatic HOCM. MANAGEMENT Coil embolization of the first two septal vessels resulted in a limited septal infarct (creatine kinase-MB 36.6 microg/l; troponin T 0.43 microg/l) that corresponded to a mass of 8.1 g on gadolinium contrast cardiac MRI. The LVOTG decreased immediately from 78 mmHg to 35 mmHg. On pressure-volume loops, contractile isovolemic and systolic ejectional parameters decreased, while an improvement in diastolic left ventricular function was observed. CONCLUSION Septal coil embolization acutely and effectively reduced the LVOTG in a patient with drug-refractory HOCM.
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Computerized Acoustic Cardiographic Electromechanical Activation Time Correlates With Invasive and Echocardiographic Parameters of Left Ventricular Contractility. J Card Fail 2008; 14:577-82. [DOI: 10.1016/j.cardfail.2008.03.011] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2007] [Revised: 02/21/2008] [Accepted: 03/28/2008] [Indexed: 11/19/2022]
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Meliga E, Steendijk P, Valgimigli M, Ten Cate FJ, Serruys PW. Effects of percutaneous transluminal septal myocardial ablation for obstructive hypertrophic cardiomyopathy on systolic and diastolic left ventricular function assessed by pressure-volume loops. Am J Cardiol 2008; 101:1179-84. [PMID: 18394455 DOI: 10.1016/j.amjcard.2007.12.016] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/12/2007] [Revised: 12/09/2007] [Accepted: 12/09/2007] [Indexed: 10/22/2022]
Abstract
The aim of the present study was to determine the long-term effects of percutaneous transluminal septal myocardial ablation (PTSMA) on systolic and diastolic left ventricular (LV) functions in patients with obstructive hypertrophic cardiomyopathy (HC). Ten consecutive patients with symptomatic HC despite optimal medical treatment were referred for PTSMA at our center. LV systolic and diastolic functions were assessed by online LV pressure-volume loops obtained by conductance catheter at baseline and at 6 months after the procedure. At follow-up, the mean gradients at rest and after extrasystole were significantly decreased compared with baseline (88 +/- 29 to 21 +/- 11 mm Hg and 130 +/- 50 to 35 +/- 22 mm Hg, respectively, p <0.01 for the 2 comparisons). End-systolic and end-diastolic pressures significantly decreased (p <0.01), whereas end-systolic and end-diastolic LV volumes significantly increased (p <0.01 for the 2 comparisons). Cardiac output and stroke volume were unchanged, as were ejection fraction (p = 0.25) and maximum dP/dt (p = 0.13). The slope of the end-systolic pressure-volume relation was not decreased, indicating a preserved contractility. The relaxation constant time, end-diastolic stiffness, projected volume of the end-diastolic pressure-volume relation at 30 mm Hg, and diastolic stiffness constant showed a significant improvement of active and passive myocardial diastolic properties. In conclusion, PTSMA is an effective method in the treatment of symptomatic patients with HC. At 6-month follow-up, the LV-aortic gradient was decreased and active and passive LV diastolic properties were increased. Myocardial contractility was not decreased and general hemodynamics was maintained.
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Wu MS, Liang JT, Lin YD, Wu ET, Tseng YZ, Chang KC. Aminoguanidine prevents the impairment of cardiac pumping mechanics in rats with streptozotocin and nicotinamide-induced type 2 diabetes. Br J Pharmacol 2008; 154:758-64. [PMID: 18376420 DOI: 10.1038/bjp.2008.119] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
BACKGROUND AND PURPOSE Aminoguanidine (AG), an inhibitor of advanced glycation endproducts, has been shown to prevent arterial stiffening and cardiac hypertrophy in streptozotocin (STZ) and nicotinamide (NA)-induced type 2 diabetes in rats. Our aims were to examine whether AG produced benefits on cardiac pumping mechanics in the STZ and NA-treated animals in terms of maximal systolic elastance (E(max)) and theoretical maximum flow (Q(max)). EXPERIMENTAL APPROACH After induction of type 2 diabetes, rats received daily injections of AG (50 mg kg(-1), i.p.) for 8 weeks and were compared with age-matched, untreated, diabetic controls. Left ventricular (LV) pressure and ascending aortic flow signals were recorded to calculate E(max) and Q(max), using the elastance-resistance model. Physically, E(max) reflects the contractility of the myocardium as an intact heart, whereas Q(max) has an inverse relationship with the LV internal resistance. KEY RESULTS Both type 2 diabetes and AG affected E(max) and Q(max), and there was an interaction between diabetes and AG for these two variables. The E(max) and Q(max) were reduced in rats with type 2 diabetes, but showed a significant rise after administration of AG to these diabetic rats. Moreover, the increase in Q(max) corresponded to a decrease in total peripheral resistance of the systemic circulation when the STZ and NA-induced diabetic rats were treated with AG. CONCLUSIONS AND IMPLICATIONS AG therapy prevented not only the contractile dysfunction of the heart, but also the augmentation in LV internal resistance in rats with STZ and NA-induced type 2 diabetes.
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Affiliation(s)
- M-S Wu
- Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan
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Yeih DF, Lin LY, Yeh HI, Lai YJ, Chiang FT, Tseng CD, Chu SH, Tseng YZ. Temporal changes in cardiac force- and flow-generation capacity, loading conditions, and mechanical efficiency in streptozotocin-induced diabetic rats. Am J Physiol Heart Circ Physiol 2008; 294:H867-74. [DOI: 10.1152/ajpheart.00573.2007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Diabetes mellitus may result in impaired cardiac contractility, but the underlying mechanisms remain unclear. We aimed to investigate the temporal alterations in cardiac force- and flow-generation capacity and loading conditions as well as mechanical efficiency in the evolution of systolic dysfunction in streptozotocin (STZ)-induced diabetic rats. Adult male Wistar rats were randomized into control and STZ-induced diabetic groups. Invasive hemodynamic studies were done at 8, 16, and 22 wk post-STZ injection. Maximal systolic elastance (Emax) and maximum theoretical flow (Qmax) were assessed by curve-fitting techniques, and ventriculoarterial coupling and mechanical efficiency were assessed by a single-beat estimation technique. In contrast to early occurring and persistently depressed Emax, Qmax progressively increased with time but was decreased at 22 wk post-STZ injection, which temporally correlated with the changes in cardiac output. The favorable loading conditions enhanced stroke volume and Qmax, whereas ventriculoarterial uncoupling attenuated the cardiac mechanical efficiency in diabetic animals. The changes in Emax and Qmax are discordant during the progression of contractile dysfunction in the diabetic heart. In conclusion, our study showed that depressed Qmax and cardiac mechanical efficiency, occurring preceding overt systolic heart failure, are two major determinants of deteriorating cardiac performance in diabetic rats.
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Kim YJ, Jones M, Greenberg NL, Popovic ZB, Sitges M, Bauer F, Thomas JD, Shiota T. Evaluation of Left Ventricular Contractile Function Using Noninvasively Determined Single-beat End-systolic Elastance in Mitral Regurgitation: Experimental Validation and Clinical Application. J Am Soc Echocardiogr 2007; 20:1086-92. [PMID: 17566701 DOI: 10.1016/j.echo.2007.02.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2006] [Indexed: 11/15/2022]
Abstract
OBJECTIVE We performed this study to validate the single-beat estimation of end-systolic elastance (E(es)) in an animal model of chronic mitral regurgitation (MR) and to use E(es) to predict postoperative left ventricular (LV) systolic function with the noninvasively derived single-beat E(es) (E(es-s)) in patients with MR. METHODS Eight sheep with MR were studied under 4 different loading conditions. E(es) was measured as the slope of the end-systolic pressure-volume relationship with a conductance catheter during inferior vena cava occlusion. E(es-s) was calculated using a bilinearly approximated time-varying elastance curve. We also studied 105 patients with MR who had undergone mitral valve repair. All measurements in these patients were performed before surgery and repeated at about 1 week after surgery. RESULTS In the animals in a total of 23 different stages, E(es-s) showed a good correlation and agreement with invasively determined E(es) (y = 0.84 x + 0.38; r = 0.8; P < .01, mean difference = 0.1 +/- 0.6 mm Hg/mL). In the clinical study, preoperative E(es-s) (r = 0.77; P < .001) and end-systolic volume index correlated well with postoperative ejection fraction (r = -0.69; P < .001). Multivariate analyses revealed that only E(es-s) was an independent predictor of postoperative LV function. Preoperative E(es-s) less than or equal to 1.0 mm Hg/mL was most predictive for identifying patients with LV dysfunction after surgery (sensitivity 87%; specificity 76%). CONCLUSIONS LV end-systolic elastance can be estimated noninvasively and is useful to detect latent LV dysfunction in patients with MR before surgery.
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Affiliation(s)
- Yong Jin Kim
- Seoul National University Hospital, Seoul, Korea
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83
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Bakhtiary F, Dogan S, Dzemali O, Ackermann H, Kleine P, Schächinger V, Moritz A, Aybek T. Impact of Different Pacing Modes on Left Ventricular Contractility Following Cardiopulmonary Bypass. PACING AND CLINICAL ELECTROPHYSIOLOGY: PACE 2007; 30:1083-90. [PMID: 17725750 DOI: 10.1111/j.1540-8159.2007.00817.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND Acute left ventricular (LV) dysfunction after cardiopulmonary bypass (CBP) is a serious complication in cardiac surgery. The aim of this study was to investigate the effect of different epicardial pacing modes on LV contractility and changes of myocardial oxygen extraction (MVO(2)) following CPB in an animal model. The utility of conductance catheter measurement versus left ventricular outflow tract mean systolic acceleration (LVOT(Acc)) for quantification of LV function was evaluated. METHODS Fourteen piglets underwent median sternotomy and CPB for 90 minutes, myocardial ischemia for 60 minutes, and reperfusion for 30 minutes. Different pacing modes were obtained before and after CPB to investigate changes in LV function. LV Function was quantified by end-systolic-pressure-volume relationships (ESPVR) as measured by the conductance catheter method and by LVOT(Acc) obtained from transepicardial echocardiographic studies. RESULTS LV contractility improved significantly by biventricular and atrial pacing compared with natural sinus rhythm (SR). MVO(2) remained stable or even decreased with biventricular pacing after surgery compared with SR. Right ventricular pacing resulted in poor LV-function with a rise of MVO(2). LVOT(Acc) showed a strong correlation to invasively measured ESPVR. CONCLUSION Postoperative biventricular pacing was associated with an improved LV contractility without rise of MVO(2) compared with SR and atrial pacing. At termination of CPB, this appears to facilitate the management of LV failure and potentially may reduce the need for inotropic support, additionally protecting myocardial metabolism. The echocardiographic assessment of LVOT(Acc) was a simple and reliable as well as effective method to quantify LV contractility and showed a good correlation with the more invasive conductance catheter.
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Affiliation(s)
- Farhad Bakhtiary
- Department of Thoracic and Cardiovascular Surgery, Johann Wolfgang Goethe University Hospital, Frankfurt/Main, Germany.
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Zhong L, Tan RS, Ghista DN, Ng EYK, Chua LP, Kassab GS. Validation of a novel noninvasive cardiac index of left ventricular contractility in patients. Am J Physiol Heart Circ Physiol 2007; 292:H2764-72. [PMID: 17237251 DOI: 10.1152/ajpheart.00540.2006] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Although there are several excellent indexes of myocardial contractility, they require accurate measurement of pressure via left ventricular (LV) catheterization. Here we validate a novel noninvasive contractility index that is dependent only on lumen and wall volume of the LV chamber in patients with normal and compromised LV ejection fraction (LVEF). By analysis of the myocardial chamber as a thick-walled sphere, LV contractility index can be expressed as maximum rate of change of pressure-normalized stress (dσ*/d tmax, where σ* = σ/P and σ and P are circumferential stress and pressure, respectively). To validate this parameter, dσ*/d tmax was determined from contrast cine-ventriculography-assessed LV cavity and myocardial volumes and compared with LVEF, dP/d tmax, maximum active elastance ( Ea,max), and single-beat end-systolic elastance [ Ees(SB)] in 30 patients undergoing clinically indicated LV catheterization. Patients with different tertiles of LVEF exhibit statistically significant differences in dσ*/d tmax. There was a significant correlation between dσ*/d tmax and dP/d tmax (dσ*/d tmax = 0.0075dP/d tmax − 4.70, r = 0.88, P < 0.01), Ea,max (dσ*/d tmax = 1.20 Ea,max + 1.40, r = 0.89, P < 0.01), and Ees(SB) [dσ*/d tmax = 1.60 Ees(SB) + 1.20, r = 0.88, P < 0.01]. In 30 additional individuals, we determined sensitivity of the parameter to changes in preload (intravenous saline infusion, n = 10 subjects), afterload (sublingual glyceryl trinitrate, n = 10 subjects), and increased contractility (intravenous dobutamine, n = 10 patients). We confirmed that the index is not dependent on load but is sensitive to changes in contractility. In conclusion, dσ*/d tmax is equivalent to dP/d tmax, Ea,max, and Ees(SB) as an index of myocardial contractility and appears to be load independent. In contrast to other measures of contractility, dσ*/d tmax can be assessed with noninvasive cardiac imaging and, thereby, should have more routine clinical applicability.
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Affiliation(s)
- Liang Zhong
- Department of Cardiology, National Heart Centre, University of New South Wales-Asia, Singapore
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Chang KC, Liang JT, Tseng CD, Wu ET, Hsu KL, Wu MS, Lin YT, Tseng YZ. Aminoguanidine prevents fructose-induced deterioration in left ventricular-arterial coupling in Wistar rats. Br J Pharmacol 2007; 151:341-6. [PMID: 17401443 PMCID: PMC2013974 DOI: 10.1038/sj.bjp.0707223] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND AND PURPOSE Aminoguanidine (AG), an inhibitor of advanced glycation endproducts, has been identified as a prominent agent that prevents the fructose-induced arterial stiffening in male Wistar rats. Our aims were to examine whether AG produced benefits on the left ventricular (LV)-arterial coupling in fructose-fed (FF) animals in terms of the ventricular and arterial chamber properties. EXPERIMENTAL APPROACH Rats given 10% fructose in drinking water (FF) were daily treated with AG (50 mg x kg(-1), i.p.) for 2 weeks and compared with the untreated FF group. In anaesthetised rats, LV pressure and ascending aortic flow signals were recorded to calculate LV end-systolic elastance (E(es), an indicator of myocardial contractility) and effective arterial volume elastance (E(a)). The optimal afterload (Q(load)) determined by the ratio of E(a) to E(es) was used to measure the coupling efficiency between the left ventricle and its vasculature. KEY RESULTS There was a significant interaction between fructose and AG in their effects on E(a). Fructose loading significantly elevated E(a) and AG prevented the fructose-derived deterioration in arterial chamber elastance. Both fructose and AG affected E(es) and Q(load), and there was an interaction between fructose and AG for these two variables. Both E(es) and Q(load) exhibited a decline with fructose feeding but showed a significant rise after AG treatment in the FF rats. CONCLUSIONS AND IMPLICATIONS AG prevented not only the contractile dysfunction of the heart caused by fructose loading, but also the fructose-induced deterioration in matching left ventricular function to the arterial system.
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Affiliation(s)
- K-C Chang
- Department of Physiology, College of Medicine, National Taiwan University, Taipei, Taiwan.
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5 Linear and Non-Linear Regression Methods in Epidemiology and Biostatistics. ACTA ACUST UNITED AC 2007. [DOI: 10.1016/s0169-7161(07)27005-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/17/2023]
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87
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Abstract
Pressure-volume analysis has provided critical insight into ventricular mechanics, and it has elucidated the underlying mechanisms of heart failure (HF). Renewed interest in ventriculovascular coupling, the interaction of the left ventricle and the arterial system, has developed from recent investigations focusing on the importance of heart rate control in systolic HF, blood pressure lability in the elderly, and acute pulmonary edema in patients with HF and a normal ejection fraction. These data suggest that abnormal ventriculovascular coupling may be an additional pathophysiologic mechanism underlying the development of HF with a normal ejection fraction and may provide a target for novel therapies.
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Affiliation(s)
- Justin M Fox
- Clinical Cardiovascular Research Laboratory for the Elderly, Allen Pavilion of New York Presbyterian Hospital, 5141 Broadway, 3 Field West, Room 035, New York, NY 10034, USA
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Abstract
Pressure-volume analysis has provided critical insight into ventricular mechanics, and it has elucidated the underlying mechanisms of heart failure (HF). Renewed interest in ventriculovascular coupling, the interaction of the left ventricle and the arterial system, has developed from recent investigations focusing on the importance of heart rate control in systolic HF, blood pressure lability in the elderly, and acute pulmonary edema in patients with HF and a normal ejection fraction. These data suggest that abnormal ventriculovascular coupling may be an additional pathophysiological mechanism underlying the development of HF with a normal ejection fraction and may provide a target for novel therapies.
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Affiliation(s)
- Justin M Fox
- Clinical Cardiovascular Research Laboratory for the Elderly, Allen Pavilion of New York Presbyterian Hospital, 5141 Broadway, 3 Field West, Room 035, New York, NY 10034, USA
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89
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Curiel R, Perez-Gonzalez J, Torres E, Landaeta R, Cerrolaza M. Operative contractility: A functional concept of the inotropic state. Clin Exp Pharmacol Physiol 2005; 32:871-81. [PMID: 16173950 DOI: 10.1111/j.1440-1681.2010.04282.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
1. Initial unsuccessful attempts to evaluate ventricular function in terms of the 'heart as a pump' led to focusing on the 'heart as a muscle' and to the concept of myocardial contractility. However, no clinically ideal index exists to assess the contractile state. The aim of the present study was to develop a mathematical model to assess cardiac contractility. 2. A tri-axial system was conceived for preload (PL), afterload (AL) and contractility, where stroke volume (SV) was represented as the volume of the tetrahedron. Based on this model, 'operative' contractility ('OperCon') was calculated from the readily measured values of PL, AL and SV. The model was tested retrospectively under a variety of different experimental and clinical conditions, in 71 studies in humans and 29 studies in dogs. A prospective echocardiographic study was performed in 143 consecutive subjects to evaluate the ability of the model to assess contractility when SV and PL were measured volumetrically (mL) or dimensionally (cm). 3. With inotropic interventions, OperCon changes were comparable to those of ejection fraction (EF), velocity of shortening (Vcf) and dP/dt-max. Only with positive inotropic interventions did elastance (Ees) show significantly larger changes. With load manipulations, OperCon showed significantly smaller changes than EF and Ees and comparable changes to Vcf and dP/dt-max. Values of OperCon were similar when AL was represented by systolic blood pressure or wall stress and when volumetric or dimensional values were used. 4. Operative contractility is a reliable, simple and versatile method to assess cardiac contractility.
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Affiliation(s)
- Roberto Curiel
- Centro Medico Docente La Trinidad, Facultad de Medicina, Universidad Central de Venezuela, Caracas, Venezuela.
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90
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Single-Beat Evaluation of Right Ventricular Contractility. Crit Care Med 2005. [DOI: 10.1097/01.ccm.0000159852.03751.37] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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91
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Poelaert JI, Schüpfer G. Hemodynamic monitoring utilizing transesophageal echocardiography: the relationships among pressure, flow, and function. Chest 2005; 127:379-90. [PMID: 15654003 DOI: 10.1378/chest.127.1.379] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
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92
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Lambermont B, Segers P, Ghuysen A, Tchana-Sato V, Morimont P, Dogne JM, Kolh P, Gerard P, D'Orio V. Comparison between single-beat and multiple-beat methods for estimation of right ventricular contractility. Crit Care Med 2004; 32:1886-90. [PMID: 15343017 DOI: 10.1097/01.ccm.0000139607.38497.8a] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE It was investigated whether pharmacologically induced changes in right ventricular contractility can be detected by a so-called "single-beat" method that does not require preload reduction. DESIGN Prospective animal research. SETTING Laboratory at a large university medical center. SUBJECTS Eight anesthetized pigs. INTERVENTIONS End-systolic elastance values obtained by a recently proposed single-beat method (Eessb) were compared with those obtained using the reference multiple-beat method (Eesmb). MEASUREMENTS AND MAIN RESULTS Administration of dobutamine increased Eesmb from 1.6 +/- 0.3 to 3.8 +/- 0.5 mm Hg/mL (p =.001), whereas there was only a trend toward an increase in Eessb from 1.5 +/- 0.2 to 1.7 +/- 0.4 mm Hg/mL. Esmolol decreased Eesmb from 1.7 +/- 0.3 to 1.1 +/- 0.2 mm Hg/mL (p =.006), whereas there was only a trend for a decrease in Eessb from 1.5 +/- 0.2 to 1.3 +/- 0.1. CONCLUSIONS The present method using single-beat estimation to assess right ventricular contractility does not work as expected, since it failed to detect either increases or decreases in right ventricular contractility induced by pharmacologic interventions.
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93
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Chang KC, Hsu KL, Chou TF, Lo HM, Tseng YZ. Aminoguanidine prevents age-related deterioration in left ventricular-arterial coupling in Fisher 344 rats. Br J Pharmacol 2004; 142:1099-104. [PMID: 15249427 PMCID: PMC1575179 DOI: 10.1038/sj.bjp.0705831] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
In recent studies, aminoguanidine (AG), an inhibitor of advanced glycation endproducts, has been identified as a prominent agent that can prevent the age-related aortic stiffening and cardiac hypertrophy. The aim of this study was to determine whether AG had effects on the left ventricular (LV)-arterial coupling in aged Fisher 344 rats in terms of the ventricular and arterial chamber properties. Normotensive rats were treated from 18 to 24 months with AG (1 g l(-1) in drinking water) and compared with a control group. LV pressure and ascending aortic flow signals were recorded to construct the ventricular and arterial end-systolic pressure-stroke volume relationships to calculate LV end-systolic elastance (Ees) and effective arterial volume elastance (Ea), respectively. The optimal afterload (Qload) determined by the ratio of Ea to Ees was used to measure the efficiency of mechanical energy transferred from the left ventricle to the arterial system. In comparison with the 6-month-old rats, the 24-month-old animals had decreased Ees, at 567.4 +/- 26.7 vs 639.0 +/- 20.7 mmHg ml(-1), decreased Ea, at 411.5 +/- 18.6 vs 577.9 +/- 15.7 mmHg ml(-1), and decreased Q(load), at 0.9428 +/- 0.0024 vs 0.9962 +/- 0.0014. Treatment with AG for 6 months did not significantly affect Ees; however, when normalized to LV weight (i.e., Eesn = Ees/LV weight), Eesn showed a significant rise of 22.8%, suggesting that AG may retard the aging process on the intrinsic contractility of the left ventricle. On the other hand, the decrease in Ea in aging rats was prevented by AG, as reflected in the increase of 19.7% in this variable (P < 0.05). The 24-month-old treated rats also exhibited a significant rise of 21.6% in Ea/Ees, causing an increase of 5.2% in Qload (P < 0.05). We conclude that in healthy older Fisher 344 rats without diabetes, long-term treatment with AG may improve both the arterial and ventricular function and optimize the matching condition for the left ventricular-arterial coupling.
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Affiliation(s)
- Kuo-Chu Chang
- Department of Physiology, College of Medicine, National Taiwan University, Taipei, Taiwan.
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94
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Werber-Zion G, Goldhammer E, Shaar A, Pollock ML. Left Ventricular Function During Strength Testing and Resistance Exercise in Patients With Left Ventricular Dysfunction. ACTA ACUST UNITED AC 2004; 24:100-9. [PMID: 15052112 DOI: 10.1097/00008483-200403000-00006] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE Deterioration in left ventricular function is a more sensitive marker of myocardial ischemia during exercise than ST segment depression. The current study was designed to evaluate left ventricular function during one-repetition-maximum (1-RM) strength testing and resistance exercise in cardiac patients with moderate left ventricular dysfunction. METHODS Using echocardiographic methods, left ventricular function was evaluated in 15 patients with left ventricular dysfunction (age, 65 +/- 6.5 years; ejection fraction, 42.1 +/- 5.8). Measurements were performed during 1-RM testing and resistance exercise (20%, 40%, and 60% of 1-RM using 10 to 15 repetitions) on the one-arm biceps curl (BIC) and bilateral knee extension exercises and compared with measurements of left ventricular function during the symptom-limited graded exercise test (SL-GXT). RESULTS During the knee extension exercise, there was a slight but significant reduction (P< or =.05) in ejection fraction values at the end of 60% 1-RM, as compared with rest and previous workloads. Significant increases in systolic blood pressure and left ventricular end-systolic volume ratio values (P< or =.05) from rest to exercise were observed across test modes and for all workloads. The prevalence of new wall motion abnormalities during knee extension and BIC 1-RM strength testing was comparable with that observed during SL-GXT. The greatest increase in new wall motion abnormalities was seen during 60% 1-RM of knee extension exercise, as compared with prior workloads, BIC exercises, and SL-GXT. CONCLUSIONS Despite an increase in occurrence of ischemic changes during the highest resistance exercise workloads and with larger muscle mass, the findings are small in magnitude and do not suggest reduced cardiac performance.
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95
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Segers P, Tchana-Sato V, Leather HA, Lambermont B, Ghuysen A, Dogne JM, Benoit P, Morimont P, Wouters PF, Verdonck P, Kolh P. Determinants of left ventricular preload-adjusted maximal power. Am J Physiol Heart Circ Physiol 2003; 284:H2295-301. [PMID: 12637350 DOI: 10.1152/ajpheart.01110.2002] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Maximal left ventricular (LV) hydraulic power output (PWR(max)), corrected for preload as PWR(max)/(V(ed))(beta) (where V(ed) is the end-diastolic volume and beta is a constant coefficient), is an index of LV contractility. Whereas preload-adjusted maximal power (PAMP) is usually calculated with beta = 2, there is uncertainty about the optimal value of beta (beta = 1 for the normal LV and 2 for the dilated LV). The aim of this work is to study the determining factors of beta. The data set consisted of 245 recordings (steady state and vena cava occlusion) in 10 animals in an ischemic heart pig model. The occlusion data yielded the slope (E(es); 2.01 +/- 0.77 mmHg/ml, range 0.71-4.16 mmHg/ml) and intercept (V(0); -11.9 +/- 22.6 ml; range -76 to 39 ml) of the end-systolic pressure-volume relation, and the optimal beta-factor (assessed by fitting an exponential curve through the V(ed)-PWR(max) relation) was 1.94 +/- 0.88 (range 0.29-4.73). The relation of beta with V(ed) was weak [beta = 0.60 + 0.02(V(ed)); r(2) = 0.20]. In contrast, we found an excellent exponential relation between V(0) and beta [beta = 2.16e(0.0189(V(0))), r(2) = 0.70]. PAMP, calculated from the steady-state data, was 0.64 +/- 0.40 mW/ml(2) (range 0.14-2.83 mW/ml(2)) with a poor correlation with E(es) (r = 0.30, P < 0.001). An alternative formulation of PAMP as PWR(max)/(V(ed) - V(0))(2), incorporating V(0), yielded 0.47 +/- 0.26 mW/ml(2) (range 0.09-1.42 mW/ml(2)) and was highly correlated with E(es) (r = 0.89, P < 0.001). In conclusion, correct preload adjustment of maximal LV power requires incorporation of V(0) and thus of data measured under altered loading conditions.
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Affiliation(s)
- Patrick Segers
- Hydraulics Laboratory, Institute Biomedical Technology, Ghent University, Belgium.
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96
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Brimioulle S, Wauthy P, Ewalenko P, Rondelet B, Vermeulen F, Kerbaul F, Naeije R. Single-beat estimation of right ventricular end-systolic pressure-volume relationship. Am J Physiol Heart Circ Physiol 2003; 284:H1625-30. [PMID: 12531727 DOI: 10.1152/ajpheart.01023.2002] [Citation(s) in RCA: 232] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Assessment of right ventricular (RV) contractility from end-systolic pressure-volume relationships (ESPVR) is difficult due to problems in measuring RV instantaneous volume and to effects of changes in RV preload or afterload. We therefore investigated in anesthetized dogs whether RV ESPVR and contractility can be determined without measuring RV volume and without changing RV preload or afterload. The maximal RV pressure of isovolumic beats (P(max)) was predicted from isovolumic portions of RV pressure during ejecting beats and compared with P(max) measured during the first beat after pulmonary artery clamping. In RV pressure-volume loops obtained from RV pressure and integrated pulmonary arterial flow, end-systolic elastance (E(es)) was assessed as the slope of P(max)-derived ESPVR, pulmonary artery effective elastance (E(a)) as the slope of end-diastolic to end-systolic relation, and coupling efficiency as the E(es)-to-E(a) ratio (E(es)/E(a)). Predicted P(max) correlated with observed P(max) (r = 0.98 +/- 0.02). Dobutamine increased E(es) from 1.07 to 2.00 mmHg/ml and E(es)/E(a) from 1.64 to 2.49, and propranolol decreased E(es)/E(a) from 1.64 to 0.91 (all P < 0.05). After adrenergic blockade, preload reduction did not affect E(es), whereas hypoxia and arterial constriction markedly increased E(a) and somewhat increased E(es) due to the Anrep effect. Low preload did not affect E(es)/E(a) and high afterload decreased E(es)/E(a). In conclusion, in the right ventricle 1) P(max) can be calculated from normal beats, 2) P(max) can be used to determine ESPVR without change in load, and 3) P(max)-derived ESPVR can be used to assess ventricular contractility and ventricular-arterial coupling efficiency.
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Affiliation(s)
- Serge Brimioulle
- Department of Intensive Care, Erasme Hospital, 808 Lennik Road, B-1070 Brussels, Belgium.
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97
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Bauer F, Jones M, Shiota T, Firstenberg MS, Qin JX, Tsujino H, Kim YJ, Sitges M, Cardon LA, Zetts AD, Thomas JD. Left ventricular outflow tract mean systolic acceleration as a surrogate for the slope of the left ventricular end-systolic pressure-volume relationship. J Am Coll Cardiol 2002; 40:1320-7. [PMID: 12383581 DOI: 10.1016/s0735-1097(02)02138-1] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
OBJECTIVE The goal of this study was to analyze left ventricular outflow tract systolic acceleration (LVOT(Acc)) during alterations in left ventricular (LV) contractility and LV filling. BACKGROUND Most indexes described to quantify LV systolic function, such as LV ejection fraction and cardiac output, are dependent on loading conditions. METHODS In 18 sheep (4 normal, 6 with aortic regurgitation, and 8 with old myocardial infarction), blood flow velocities through the LVOT were recorded using conventional pulsed Doppler. The LVOT(Acc) was calculated as the aortic peak velocity divided by the time to peak flow; LVOT(Acc) was compared with LV maximal elastance (E(m)) acquired by conductance catheter under different loading conditions, including volume and pressure overload during an acute coronary occlusion (n = 10). In addition, a clinically validated lumped-parameter numerical model of the cardiovascular system was used to support our findings. RESULTS Left ventricular E(m) and LVOT(Acc) decreased during ischemia (1.67 +/- 0.67 mm Hg.ml(-1) before vs. 0.93 +/- 0.41 mm Hg.ml(-1) during acute coronary occlusion [p < 0.05] and 7.9 +/- 3.1 m.s(-2) before vs. 4.4 +/- 1.0 m.s(-2) during coronary occlusion [p < 0.05], respectively). Left ventricular outflow tract systolic acceleration showed a strong linear correlation with LV E(m) (y = 3.84x + 1.87, r = 0.85, p < 0.001). Similar findings were obtained with the numerical modeling, which demonstrated a strong correlation between predicted and actual LV E(m) (predicted = 0.98 [actual] -0.01, r = 0.86). By analysis of variance, there was no statistically significant difference in LVOT(Acc) under different loading conditions. CONCLUSIONS For a variety of hemodynamic conditions, LVOT(Acc) was linearly related to the LV contractility index LV E(m) and was independent of loading conditions. These findings were consistent with numerical modeling. Thus, this Doppler index may serve as a good noninvasive index of LV contractility.
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Affiliation(s)
- Fabrice Bauer
- Cleveland Clinic Foundation, Cleveland, Ohio 44195, USA
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98
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Kjørstad KE, Korvald C, Myrmel T. Pressure-volume-based single-beat estimations cannot predict left ventricular contractility in vivo. Am J Physiol Heart Circ Physiol 2002; 282:H1739-50. [PMID: 11959639 DOI: 10.1152/ajpheart.00638.2001] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The end-systolic pressure-volume relationship is regarded as a useful index for assessing the contractile state of the heart. However, the need for preload alterations has been a serious limitation to its clinical applications, and there have been numerous attempts to develop a method for calculating contractility based on one single pressure-volume loop. We have evaluated four of these methods. Pressure-volume data were obtained by combined pressure and conductance catheters in 37 pigs. All four methods were applied to 88 steady-state pressure-volume files, including eight files sampled during dopamine infusions. Estimates of single-beat contractility (elastance) were compared with preload-varied multiple-beat elastance [E(es(MB))]. All methods had a low average bias (-0.3 to 0.5 mmHg/ml) but limits of agreement (+/-2 SD) were unacceptably high (+/-2.6 to +/-3.8 mmHg/ml). In the dopamine group, E(es(MB)) showed an increase of 1.7 +/- 0.8 mmHg/ml (mean +/- SD) compared with baseline (P < 0.001). None of the single-beat methods predicted this increase in contractility. It is therefore doubtful whether any of the methods allow for single-beat assessment of contractility.
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Affiliation(s)
- Knut E Kjørstad
- Department of Thoracic and Cardiovascular Surgery, University Hospital of Tromsø, N-9038 Tromsø, Norway.
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99
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Chang KC, Lo HM, Tseng YZ. Systolic elastance and resistance in the regulation of cardiac pumping function in early streptozotocin-diabetic rats. Exp Biol Med (Maywood) 2002; 227:251-9. [PMID: 11910047 DOI: 10.1177/153537020222700405] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
We determined the roles of maximal systolic elastance (E(max)) and theoretical maximum flow ((max)) in the regulation of cardiac pumping function in early streptozotocin (STZ)-diabetic rats. Physically, E(max) can reflect the intrinsic contractility of the myocardium as an intact heart, and (max) has an inverse relation to the systolic resistance of the left ventricle. Rats given STZ 65 mg/kg i.v. (n = 17) were divided into two groups, 1 week and 4 weeks after induction of diabetes, and compared with untreated age-matched controls (n = 15). Left ventricular (LV) pressure and ascending aortic flow signals were recorded to calculate E(max) and (max), using the elastance-resistance model. After 1 or 4 weeks, STZ-diabetic animals show an increase in effective LV end-diastolic volume (V(eed)), no significant change in peak isovolumic pressure (P(iso)(max)), and a decline in effective arterial volume elastance (E(a)). The maximal systolic elastance E(max) is reduced from 751.5 +/- 23.1 mmHg/ml in controls to 514.1 +/- 22.4 mmHg/ml in 1- and 538.4 +/- 33.8 mmHg/ml in 4-week diabetic rats. Since E(max) equals P(iso)(max)/V(eed), an increase in V(eed) with unaltered P(iso)(max) may primarily act to diminish E(max) so that the intrinsic contractility of the diabetic heart is impaired. By contrast, STZ-diabetic rats have higher theoretical maximum flow (max) (40.9 +/- 2.8 ml/s in 1- and 44.5 +/- 3.8 ml/s in 4-week diabetic rats) than do controls (30.7 +/- 1.7 ml/s). There exists an inverse relation between (max) and E(a) when a linear regression of (max) on E(a) is performed over all animals studied (r = 0.65, p < 0.01). The enhanced (max) is indicative of the decline in systolic resistance of the diabetic rat heart. The opposing effects of enhanced (max) and reduced E(max) may negate each other, and then the cardiac pumping function of the early STZ-diabetic rat heart could be preserved before cardiac failure occurs.
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Affiliation(s)
- Kuo-Chu Chang
- Department of Physiology and Department of Internal Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan.
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100
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Eucker SA, Lisauskas J, Courtois MR, Kovács SJ. Analysis of left ventricular hemodynamics in physiological hyperspace. J Appl Physiol (1985) 2002; 92:323-30. [PMID: 11744675 DOI: 10.1152/japplphysiol.00560.2001] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Our laboratory has previously shown that it is possible to elucidate novel physiological relationships by analyzing the left ventricular pressure (P) contour in the phase [time derivative of P (dP/dt) vs. P] plane (Eucker SA, Lisauskas JB, Singh J, and Kovács SJ, J Appl Physiol 90: 2238-2244, 2001). To further characterize cardiac physiology, we introduce a method that combines P-volume (V) and phase plane-derived information in physiological hyperspace. From four-dimensional (P, V, dP/dt, time derivative of V) hyperspace, we consider three-dimensional embedding diagrams having dP/dt, P, and V as coordinate axes. Our method facilitates analysis of physiological function independent of inotropic state and permits assessment of P-V-based relationships in the phase plane and vice versa. To test feasibility, the method was applied to murine hemodynamic data. As predicted from first principles, the area of the P-V loop (ventricular external work) correlated closely (r = 0.97) with phase plane limit cycle area (external power). The P-V plane-derived linear (r = 0.99) end-systolic P-V relationship (maximum elastance) appeared linear in the phase plane (r = 0.85). We conclude that analysis of data in physiological hyperspace is generalizable: it facilitates quantitative characterization of ventricular systolic and diastolic function and can guide discovery of novel physiological relationships.
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Affiliation(s)
- Stephanie A Eucker
- Cardiovascular Biophysics Laboratory, Washington University, St. Louis, Missouri 63110, USA
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