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If Only the Slope Could Tell*. Crit Care Med 2020; 48:1540-1542. [DOI: 10.1097/ccm.0000000000004534] [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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Lertwanakarn T, Suntravat M, Sanchez EE, Boonhoh W, Solaro RJ, Wolska BM, Martin JL, de Tombe PP, Tachampa K. Suppression of cardiomyocyte functions by β-CTX isolated from the Thai king cobra ( Ophiophagus hannah) venom via an alternative method. J Venom Anim Toxins Incl Trop Dis 2020; 26:e20200005. [PMID: 32742278 PMCID: PMC7375408 DOI: 10.1590/1678-9199-jvatitd-2020-0005] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Accepted: 06/16/2020] [Indexed: 12/20/2022] Open
Abstract
Background Beta-cardiotoxin (β-CTX), the three-finger toxin isolated from king cobra (Ophiophagus hannah) venom, possesses β-blocker activity as indicated by its negative chronotropy and its binding property to both β-1 and β-2 adrenergic receptors and has been proposed as a novel β-blocker candidate. Previously, β-CTX was isolated and purified by FPLC. Here, we present an alternative method to purify this toxin. In addition, we tested its cytotoxicity against different mammalian muscle cell types and determined the impact on cardiac function in isolated cardiac myocyte so as to provide insights into the pharmacological action of this protein. Methods β-CTX was isolated from the crude venom of the Thai king cobra using reverse-phased and cation exchange HPLC. In vitro cellular viability MTT assays were performed on mouse myoblast (C2C12), rat smooth muscle (A7r5), and rat cardiac myoblast (H9c2) cells. Cell shortening and calcium transient dynamics were recorded on isolated rat cardiac myocytes over a range of β-CTX concentration. Results Purified β-CTX was recovered from crude venom (0.53% w/w). MTT assays revealed 50% cytotoxicity on A7r5 cells at 9.41 ± 1.14 µM (n = 3), but no cytotoxicity on C2C12 and H9c2 cells up to 114.09 µM. β-CTX suppressed the extend of rat cardiac cell shortening in a dose-dependent manner; the half-maximal inhibition concentration was 95.97 ± 50.10 nM (n = 3). In addition, the rates of cell shortening and re-lengthening were decreased in β-CTX treated myocytes concomitant with a prolongation of the intracellular calcium transient decay, indicating depression of cardiac contractility secondary to altered cardiac calcium homeostasis. Conclusion We present an alternative purification method for β-CTX from king cobra venom. We reveal cytotoxicity towards smooth muscle and depression of cardiac contractility by this protein. These data are useful to aid future development of pharmacological agents derived from β-CTX.
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Affiliation(s)
- Tuchakorn Lertwanakarn
- Department of Physiology, Faculty of Veterinary Science, Chulalongkorn University, Bangkok, Thailand
| | - Montamas Suntravat
- National Natural Toxins Research Center, Texas A&M University-Kingsville, Kingsville, TX, USA.,Department of Chemistry, Texas A&M University-Kingsville, Kingsville, TX, USA
| | - Elda E Sanchez
- National Natural Toxins Research Center, Texas A&M University-Kingsville, Kingsville, TX, USA.,Department of Chemistry, Texas A&M University-Kingsville, Kingsville, TX, USA
| | - Worakan Boonhoh
- Department of Physiology, Faculty of Veterinary Science, Chulalongkorn University, Bangkok, Thailand
| | - R John Solaro
- Department of Physiology and Biophysics, University of Illinois at Chicago, IL, USA
| | - Beata M Wolska
- Department of Physiology and Biophysics, University of Illinois at Chicago, IL, USA.,Department of Medicine, University of Illinois at Chicago, IL, USA
| | - Jody L Martin
- Department of Physiology and Biophysics, University of Illinois at Chicago, IL, USA
| | - Pieter P de Tombe
- Department of Physiology and Biophysics, University of Illinois at Chicago, IL, USA
| | - Kittipong Tachampa
- Department of Physiology, Faculty of Veterinary Science, Chulalongkorn University, Bangkok, Thailand
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Grapsa J. Left Ventricular Ejection Fraction and Global Longitudinal Strain. J Am Coll Cardiol 2018; 72:1065-1066. [DOI: 10.1016/j.jacc.2018.05.070] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Revised: 05/15/2018] [Accepted: 05/20/2018] [Indexed: 11/24/2022]
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Thiele RH, Bartels K, Esper S, Ikeda K, Gan TJ. Real-time Doppler-based arterial vascular impedance and peripheral pressure-flow loops: a pilot study. J Cardiothorac Vasc Anesth 2013; 28:36-41. [PMID: 24075638 DOI: 10.1053/j.jvca.2013.04.021] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2013] [Indexed: 11/11/2022]
Abstract
OBJECTIVE Arterial pressure-flow loops and vascular impedance provide additional data that could be used to assess the hemodynamic effects of therapeutic interventions in anesthetized patients. To evaluate the utility of such an approach, the authors sought to design a device that combines flow waveforms from an esophageal Doppler probe and pressure waveforms from a peripheral artery to produce real-time pressure-flow loops and estimates of arterial vascular impedance. DESIGN Prospective, cohort study. SETTING Single center, university-based teaching hospital. PARTICIPANTS Patients undergoing surgery in whom the attending anesthesiologist had opted to place an esophageal Doppler probe and a peripheral arterial catheter for hemodynamic monitoring. INTERVENTIONS This was a non-interventional study designed to record pressure-flow loops and arterial vascular impedance intraoperatively using a novel, noninvasive device. MEASUREMENTS AND MAIN RESULTS Pressure-flow loops and arterial vascular impedance were measured noninvasively using radial artery pressure and descending thoracic aorta flow waveforms in real time. CONCLUSIONS Real-time arterial vascular impedance and peripheral pressure-volume loops can be determined using available monitoring devices. Technical feasibility of this technology in patients is a crucial first step to permit meaningful evaluation of the clinical value of this approach for accurate determination of complex hemodynamic indices and, eventually, improvement of outcomes.
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Affiliation(s)
- Robert H Thiele
- Technology in Anesthesia and Critical Care Group, University of Virginia, Charlottesville, VA.
| | - Karsten Bartels
- Department of Anesthesiology, University of Colorado Denver, Aurora, CO
| | - Stephen Esper
- Department of Anesthesiology, University of Pittsburgh, Pittsburgh, PA
| | - Keita Ikeda
- Department of Anesthesiology, Duke University, Durham, NC
| | - Tong-Joo Gan
- Department of Anesthesiology, Duke University, Durham, NC
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Ochagavía A, Zapata L, Carrillo A, Rodríguez A, Guerrero M, Ayuela JM. [Evaluation of contractility and postloading in the intensive care unit]. Med Intensiva 2012; 36:365-74. [PMID: 22482957 DOI: 10.1016/j.medin.2012.02.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2012] [Accepted: 02/19/2012] [Indexed: 11/26/2022]
Abstract
Cardiovascular failure is a common disorder in critical care medicine. When admitted to the ICU, patients with hemodynamic deterioration should be examined rapidly to correctly assess the main determinants of cardiovascular function (preload, afterload and contractility). This review examines the assessment of contractility and afterload involving the combined use of several hemodynamic monitors, which allows different approaches to the same problem, with a view to improving the efficiency of management and treatment in critically ill patients.
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Affiliation(s)
- A Ochagavía
- Servicio de Medicina Intensiva, Hospital de Sabadell, CIBER Enfermedades Respiratorias, Institut Universitari Parc Tauli, UAB, Sabadell, Barcelona, España.
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Fatkin D, Yeoh T, Hayward CS, Benson V, Sheu A, Richmond Z, Feneley MP, Keogh AM, Macdonald PS. Evaluation of left ventricular enlargement as a marker of early disease in familial dilated cardiomyopathy. ACTA ACUST UNITED AC 2011; 4:342-8. [PMID: 21636824 DOI: 10.1161/circgenetics.110.958918] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Echocardiographic screening of families with dilated cardiomyopathy has identified a subgroup of asymptomatic relatives with left ventricular enlargement (LVE). The prognostic significance of LVE in this setting is incompletely understood. METHODS AND RESULTS We evaluated 457 asymptomatic relatives in 128 dilated cardiomyopathy families and identified 110 individuals (24%) with LVE. Serial echocardiograms in 72 untreated LVE relatives showed that 9 individuals (13%) had development of dilated cardiomyopathy over 10 to 152 months (median, 52). Thirty LVE relatives and 30 age- and sex-matched healthy control subjects were evaluated using 2-dimensional and M-mode echocardiography, tissue Doppler imaging, noninvasive pressure-volume assessment, exercise stress echocardiography, and brain natriuretic peptide levels. LVE relatives showed mild defects of systolic and diastolic LV function, with normal filling pressures and exercise-induced increments in systolic contraction in most cases. LV dimensions and fractional shortening most effectively differentiated LVE relatives from control subjects, with other functional indices lacking additive discriminative value. In a receiver operating characteristics analysis, the area under the curve for LV end-diastolic diameter (% predicted) was 0.96 (P<0.001). LV end-diastolic diameter (% predicted) >116% or LV end-diastolic diameter (% predicted) 112% to 116%+fractional shortening ≤29% had high sensitivity (100%) and specificity (93%) for LVE relatives and identified 8 of 9 progressors. CONCLUSIONS LVE is a common finding in asymptomatic relatives in dilated cardiomyopathy families and can be a marker of preclinical cardiomyopathy. Assessment of LV size and contractile function is required for differentiating between pathological and physiological causes of LVE and may help to identify those at risk of disease progression.
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Affiliation(s)
- Diane Fatkin
- Molecular Cardiology Division, Victor Chang Cardiac Research Institute, Darlinghurst, New South Wales, Australia.
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Black A, Grenz N, Niccole S, Arndt P, Lucht J, Nesvig K, Ewert D, Mulligan L. Assessment of dsigma*/dt (max), a load independent index of contractility, in the canine. CARDIOVASCULAR ENGINEERING (DORDRECHT, NETHERLANDS) 2009; 9:49-55. [PMID: 19466542 DOI: 10.1007/s10558-009-9073-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2008] [Accepted: 05/11/2009] [Indexed: 05/27/2023]
Abstract
The search for a load-independent index of myocardial contractility has been a focus for nearly 100 years. Nearly all of the parameters developed have yielded insight into cardiac function but their clinical utility has been limited. A new index, dsigma*/dt (max), has been proposed to be useful in the clinic. This parameter is expressed as the maximum time rate of change of the pressure normalized circumferential wall stress (sigma* = sigma ( theta )/P, where sigma ( theta ) is circumferential wall stress and P is pressure) for a thick walled sphere model of the left ventricle (LV). This definition for a contractility index renders dsigma*/dt (max) dependent only on LV wall volume (V (m)) and maximum time rate of change of the ventricular volume, dV/dt (max). The index dsigma*/dt (max) has been studied in patients with echocardiogram-derived volume, but up until this point its characteristics in canines have remained unknown. Validating this index in the canine will allow for a more intensive and wide-range investigation of the index that is not available with humans. The purpose of this study was to validate dsigma*/dt (max) as a load-independent measure of contractility in the canine heart with the hope that it was a noninvasive assessment of contractile function. To assess the load independence of dsigma*/dt (max), the index was estimated over a range of preloads (end diastolic volume, EDV) during a vena caval occlusion (VCO). The study was conducted in five canines under various pacing modes [right atrial (RA), right ventricular (RV), left ventricular (LV), and biventricular (BV)] at rates of 90 or 100, and 160 bpm. The animals' ventricular volume measurements were assessed by conductance catheter, calibrated with echocardiography. A 50 Hz filter was applied to the volume signal before differentiation to obtain dV/dt (max). Echocardiography was used to calculate left ventricle mass and V (m). In eight of ten cases, dsigma*/dt (max) was significantly correlated with decreasing EDV (p < 0.05). There was also a significant correlation between dsigma*/dt (max) and dP/dt (max). With a strong correlation between the values of dsigma*/dt (max), dP/dt (max), and EDV in all five subjects, dsigma*/dt (max) is not load independent in the canine heart when preload is altered by a VCO. Further evaluation of this index is required to delineate the situations where dsigma*/dt (max) can be accurately applied.
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Affiliation(s)
- Adam Black
- Therapy Delivery, Medtronic, Minneapolis, MN, USA
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Licker M, Sierra J, Kalangos A, Panos A, Diaper J, Ellenberger C. Cardioprotective effects of acute normovolemic hemodilution in patients with severe aortic stenosis undergoing valve replacement. Transfusion 2007; 47:341-50. [PMID: 17302782 DOI: 10.1111/j.1537-2995.2007.01111.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
BACKGROUND After acute normovolemic hemodilution (ANH), improvement of the rheologic conditions may contribute to optimize tissue oxygen delivery and attenuate ischemia-reperfusion injuries. It was hypothesized that ANH would confer additional cardioprotection in patients with ventricular hypertrophy undergoing open heart surgery. STUDY DESIGN AND METHODS This study was a randomized controlled trial. Forty patients scheduled for elective aortic valve replacement were randomly assigned to a control group (standard care) or an ANH group (target hematocrit level of 28%). All patients were managed with standard myocardial preservation techniques (cold blood cardioplegia, anesthetic preconditioning). The outcome measures included the release of myocardial enzymes, perioperative hemodynamic changes, the need for pharmacologic cardiovascular support, and cardiac complications. RESULTS In the ANH group, the postoperative release of troponin I (mean peak plasma concentrations, 1.7 ng/mL; 95% confidence interval, 1.4-2.1 ng/mL) and myocardial fraction of creatine kinase (22 U/L; range, 18-24 U/L) was significantly lower than in the control group (3.6 [range, 3.0-4.2] ng/mL and 45 [range, 39-51] U/L, respectively). In addition, requirement for inotropic support was significantly lower and fewer hemodiluted patients presented adverse cardiac events. After ANH, there was a significant decrease in heart rate (-11 +/- 6%) and rate-pressure product (-16 +/- 8%) until the aortic cross-clamping time and, at the end of surgery, the circulating levels of erythropoietin (EPO) were higher than in control patients (13.6 +/- 4.2 mUI/mL vs. 7.3 +/- 2.4 mUI/mL; p < 0.05). CONCLUSIONS Besides conventional cardiac preservation techniques, preoperative ANH further attenuates myocardial injuries. Optimization of preischemic myocardial oxygen delivery and/or consumption and the postconditioning effects of endogenous EPO are potential mechanisms for ANH-induced cardioprotection.
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Affiliation(s)
- Marc Licker
- Department of Anesthesiology, Pharmacology and Surgical Intensive Care, University Hospital of Geneva, Geneva, Switzerland.
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Abstract
PURPOSE OF REVIEW We review new findings concerning ventricular function in patients in intensive care units with shock or unexplained respiratory distress syndrome analyzed using echocardiography. RECENT FINDINGS Bedside echocardiography is not only an imaging technique but should be considered as a hemodynamic method. Left-ventricular systolic function can be assessed in daily clinical practice by measuring shortening fraction, fraction area change and ejection fraction. But these indices are dependent on load conditions. Index of myocardial performance can be also used. Rate of left-ventricular pressure increase may be measured from mitral regurgitation. Other indices such a maximal elastance and preload-adjusted maximal power were developed to evaluate myocardial systolic function but are not still used in clinical practice in patients in intensive care. Cardiac output measurement can be calculated easily from aortic annulus diameter and the velocity time integral of aortic blood flow. To complete the assessment of ventricular function, left-ventricular diastolic function and pressure as well as right ventricular size, septal movement and right pressures should be analyzed. SUMMARY Using echocardiography the intensivist can examine both the mechanism and the cause of shock or pulmonary edema. It is time to increase the use of this technique in intensive care units.
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Affiliation(s)
- Michel Slama
- INSERM, ERI 12, Amiens, France and unite de reanimation, service de nephrologie, CHU sud Amiens, France.
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Senzaki H, Masutani S, Ishido H, Taketazu M, Kobayashi T, Sasaki N, Asano H, Katogi T, Kyo S, Yokote Y. Cardiac Rest and Reserve Function in Patients With Fontan Circulation. J Am Coll Cardiol 2006; 47:2528-35. [PMID: 16781384 DOI: 10.1016/j.jacc.2006.03.022] [Citation(s) in RCA: 118] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2005] [Revised: 01/30/2006] [Accepted: 02/07/2006] [Indexed: 10/24/2022]
Abstract
OBJECTIVES In the present study, we systematically tested cardiac rest and reserve function in patients with Fontan physiology to check for inherent limitations of this circulation. BACKGROUND Details of the mechanisms of cardiac performance that could account for adverse outcome after Fontan surgery are not well understood. METHODS The subjects were 17 Fontan patients with good functional status (Fontan group) and 20 patients with normal two-ventricle circulation (control group). We examined baseline ventricular contractility, diastolic function, and loading factors, and examined changes in those parameters in response to increased heart rate (HR) due to atrial pacing and in response to beta-adrenergic stimulation, using ventricular pressure-area relationships during preload reduction. RESULTS At baseline, the Fontan patients exhibited minimal abnormality of cardiac properties, but the significant increase in afterload resulted in decreased cardiac index. In addition, Fontan circulation was associated with limited inotropic response and worsening of diastolic filling with increased HR, leading to decreased systolic pressure and elevation of central venous pressure at higher HRs (p < 0.05 vs. control). Furthermore, beta-adrenergic reserve was markedly decreased in the Fontan group, compared with controls, owing to limited preload reserve rather than limited contractile reserve. CONCLUSIONS Because normal ventricular-vascular interaction and augmentation of cardiac performance during increased HR and adrenergic stimulation are important for maintaining cardiac output and exercise capacity, the present results may have important implications for the mechanisms underlying adverse outcome after Fontan surgery. Thus, improvement of long-term prognosis of patients after Fontan surgery requires the development of medical interventions that can overcome such limitations inherent in Fontan circulation.
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Affiliation(s)
- Hideaki Senzaki
- Department of Pediatric Cardiology and Cardiovascular Surgery, Saitama Medical School Hospital, Iruma-Gun, Saitama, Japan.
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Licker M, Ellenberger C, Sierra J, Christenson J, Diaper J, Morel D. Cardiovascular response to acute normovolemic hemodilution in patients with coronary artery diseases: Assessment with transesophageal echocardiography. Crit Care Med 2005; 33:591-7. [PMID: 15753752 DOI: 10.1097/01.ccm.0000156446.03285.e0] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE Preoperative acute normovolemic hemodilution induces an increase in circulatory output that is thought to be limited in patients with cardiac diseases. Using multiple-plane transesophageal echocardiography, we investigated the mechanisms of cardiovascular adaptation during acute normovolemic hemodilution in patients with severe coronary artery disease. DESIGN Prospective case-control study. SETTING Operating theater in a university hospital. PATIENTS Consecutive patients treated with beta-blockers, scheduled to undergo coronary artery bypass (n = 50). INTERVENTIONS After anesthesia induction, blood withdrawal and isovolemic exchange with iso-oncotic starch (1:1.15 ratio) to achieve a hematocrit value of 28%. MEASUREMENTS AND MAIN RESULTS In addition to heart rate and intravascular pressures, echocardiographic recordings were obtained before and after acute normovolemic hemodilution to assess cardiac preload, afterload, and contractility. In a control group, not subjected to acute normovolemic hemodilution, hemodynamic variables remained stable during a 20-min anesthesia period. Following acute normovolemic hemodilution, increases in cardiac stroke volume (+28 +/- 4%; mean +/- sd) were correlated with increases in central venous pressure (+2.0 +/- 1.3 mm Hg; R = .56) and in left ventricular end-diastolic area (+18 +/- 5%, R = .39). The unchanged left ventricular end-systolic wall stress and preload-adjusted maximal power indicated that neither left ventricular afterload nor contractility was affected by acute normovolemic hemodilution. Diastolic left ventricular filling abnormalities (15 of 22 cases) improved in 11 patients and were stable in the remaining four patients. Despite reduction in systemic oxygen delivery (-20.5 +/- 7%, p < .05), there was no evidence for myocardial ischemia (electrocardiogram, left ventricular wall motion abnormalities). CONCLUSIONS In anesthetized patients with coronary artery disease, moderate acute normovolemic hemodilution did not compromise left ventricular systolic and diastolic function. Lowering blood viscosity resulted in increased stroke volume that was mainly related to increased venous return and higher cardiac preload.
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Affiliation(s)
- Marc Licker
- Department of Anesthesiology, Pharmacology and Surgical Intensive Care, University Hospital of Geneva
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Schenk S, Popović ZB, Ochiai Y, Casas F, McCarthy PM, Starling RC, Kopcak MW, Dessoffy R, Navia JL, Greenberg NL, Thomas JD, Fukamachi K. Preload-adjusted right ventricular maximal power: concept and validation. Am J Physiol Heart Circ Physiol 2004; 287:H1632-40. [PMID: 15155255 DOI: 10.1152/ajpheart.00123.2004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Right ventricular (RV) maximal power (PWRmx) is dependent on preload. The objective of this study was to test our hypothesis that the PWRmx versus end-diastolic volume (EDV) relationship, analogous to the load-independent stroke work (SW) versus EDV relationship (preload-recruitable SW, PRSW), is linear, with the PWR x-axis intercept (V0PWR) corresponding to the PRSW intercept (V0SW). If our hypothesis is correct, the preload sensitivity of PWRmx could be eliminated by adjusting for EDV and V0PWR. Ten dogs were instrumented with a pulmonary flow probe, micromanometers, and RV conductance catheter. Data were obtained during bicaval occlusions under various conditions and fitted to PWRmx = a·(EDV − V0PWR)β, where a is the slope of the relationship. The PWRmx versus EDV relationship did not deviate from linearity (β = 1.09, P = not significant vs. 1), and V0PWR correlated with V0SW ( r = 0.93, P <0.0001). V0PRW was related to steady-state EDV and left ventricular end-diastolic pressure, allowing for estimation of V0PWR (V0Est) and single-beat PWRmx preload adjustment. Dividing PWRmx by the difference of EDV and V0PWR (PAMPV0PWR) eliminated preload dependency down to 50% of the baseline EDV. PWRmx adjustment using V0Est (PAMPV0Est) showed similar preload independency. Enhancing contractility increased PAMPV0PWR and PAMPV0Est from 176 ± 52 to 394 ± 205 W/ml × 104 and 145 ± 51 to 404 ± 261 W/ml × 104, respectively, accompanied by an increase of PRSW from 13.0 ± 4.5 to 29.7 ± 16.4 mmHg (all P <0.01). PAMPV0PWR and PAMPV0Est correlated with PRSW ( r = 0.85; r = 0.77; both P <0.001). Numerical modeling confirmed the accuracy of our experimental data. Thus preload adjustment of PWRmx should consider a linear PWRmx versus EDV relationship with distinct V0PWR. PAMPV0PWR is a preload-independent estimate of RV contractility that may eventually be determined noninvasively.
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Affiliation(s)
- Soren Schenk
- Dept. of Biomedical Engineering/ ND20, Cleveland Clinic Foundation, 9500 Euclid Avenue, Cleveland, OH 44195, USA
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Abstract
Heart failure remains a significant health problem in the United States and in the world. Despite a surfeit of recent diagnostic and therapeutic advances, patients with heart failure remain inadequately helped. The overwhelming need for new and better therapies continues to stimulate scientists to investigate new technologies. Over the past several years the use of enhanced external counterpulsation as a treatment for chronic angina has steadily increased. Recently, its potential role in heart failure management has been shown. We review the role of enhanced external counterpulsation in heart failure management as an emerging noninvasive outpatient therapy.
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Affiliation(s)
- Ozlem Soran
- Cardiovascular Institute, EECP Research Laboratory, University of Pittsburgh, Pittsburgh, Pennsylvania 15213, USA.
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Lester SJ, Shin H, Lambert AS, Miller JP, Cahalan MK, Seeberger MD, Foster E, Schiller NB. Is PA-PWRmax truly a preload-independent index of myocardial contractility in anesthetized humans? Cardiology 2004; 102:77-81. [PMID: 15103176 DOI: 10.1159/000077908] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/21/2003] [Accepted: 12/22/2003] [Indexed: 11/19/2022]
Abstract
This study tested the hypothesis that the preload-adjusted maximal power index (PA-PWRmax) is a load-independent index of human myocardial contractility. Based on the ventricular pressure-volume relationship and derived from stroke work, the index is the product of instantaneous ventricular pressure and volume changes, divided by a correction term of end-diastolic volume (EDV2) or end-diastolic area (EDA3/2) to adjust for preload effects. Echocardiographic measures of instantaneous ventricular area change may be used to obtain PA-PWRmax noninvasively. We prospectively evaluated 28 human subjects undergoing cardiac evacuation before cardiopulmonary bypass procedures. Continuous peripheral arterial pressure, pulmonary arterial pressure, and echocardiographic views of the left ventricle in the transgastric short-axis view were recorded. Simultaneously gated instantaneous fractional shortening (FS) and PA-PWRmax indices were calculated, with FS = (EDA - ESA)/EDA and PA-PWRmax = [MAP (EDA - ESA)]/ EDA3/2, where ESA = end-systolic area and MAP = instantaneous mean arterial pressure. FS decreased uniformly with cardiac evacuation and decreasing pulmonary artery diastolic pressure (t = -5.4; 95% confidence interval, -10 to -0.046; p < 0.001), as did PA-PWRmax (t = -5.8; 95% confidence interval, -2.25 to -1.08; p < 0.001). FS and PA-PWRmax showed a strong downward correlation (r = 0.81). Unlike previous studies of autonomically denervated animals, our study did not find PA-PWRmax to be preload independent, perhaps because of the instantaneous homeostatic mechanisms of the human autonomic nervous system linking contractility to loading conditions.
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Affiliation(s)
- Steven J Lester
- Adult Echo Laboratory, University of California, San Francisco, San Francisco, Calif, USA
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Marwick TH. Techniques for comprehensive two dimensional echocardiographic assessment of left ventricular systolic function. BRITISH HEART JOURNAL 2003; 89 Suppl 3:iii2-8. [PMID: 14594869 PMCID: PMC1876300 DOI: 10.1136/heart.89.suppl_3.iii2] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- T H Marwick
- University of Queensland Department of Medicine, Princess Alexandra Hospital, Brisbane, Qld 4102, Australia.
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Royse CF, Royse AG, Wong CT, Soeding PF. The effect of pericardial restraint, atrial pacing, and increased heart rate on left ventricular systolic and diastolic function in patients undergoing cardiac surgery. Anesth Analg 2003; 96:1274-1279. [PMID: 12707119 DOI: 10.1213/01.ane.0000055801.23956.c2] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
UNLABELLED Baseline measurements of systolic and diastolic function performed after the induction of anesthesia may be compared with subsequent measurements acquired under different physical conditions such as open pericardium and different heart rate or rhythm. We acquired data from 21 patients undergoing coronary artery surgery. Combined echocardiographic and pulmonary artery catheter measurements were performed before and after pericardial opening, atrial pacing at the native rate, and atrial pacing 30 bpm faster. Indices of systolic function included fractional area change, afterload corrected fractional area change, and myocardial performance index; diastolic function included mitral inflow and pulmonary vein Doppler profiles, color M-Mode Doppler flow propagation velocity, instantaneous end-diastolic stiffness, and isovolumetric relaxation time. Hemodynamic indices included cardiac index, mean arterial, right atrial, and pulmonary capillary wedge pressures, and systemic vascular resistance index. There were no changes in measurements after opening of the pericardium or with institution of atrial pacing. With increased heart rate, there were no changes in systolic function, but instantaneous end-diastolic stiffness increased. Propagation velocity showed a paradoxical improvement with increased heart rate opposite to other trends. Beat fusion occurs with increasing heart rate for mitral inflow Doppler. We recommend that serial measurements are performed at a similar heart rate. IMPLICATIONS Pericardial restraint or the institution of atrial pacing do not alter left ventricular function, as assessed by pulmonary artery catheter and transesophageal echocardiography measurements. Diastolic (but not systolic) measurements showed inconsistency with increased heart rate.
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Affiliation(s)
- Colin F Royse
- *Department of Pharmacology, University of Melbourne; and Departments of †Anaesthesia and Pain Management and ‡Cardiothoracic Surgery, The Royal Melbourne Hospital, Australia
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Leather HA, Segers P, Sun YY, De Ruyter HA, Vandermeersch E, Wouters PF. The limitations of preload-adjusted maximal power as an index of right ventricular contractility. Anesth Analg 2002; 95:798-804, table of contents. [PMID: 12351248 DOI: 10.1097/00000539-200210000-00003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
UNLABELLED Right ventricular (RV) dysfunction is an important cause of perioperative morbidity and mortality, particularly in cardiac surgery. However, assessment of RV contractility remains difficult in clinical practice. Our goal in this study was to examine the value of preload-adjusted maximal power (PWR(max)/end-diastolic volume [EDV](2); PAMP) as an alternative to the load-independent pressure-volume-derived indices of contractility in the RV. In anesthetized dogs, RV end-systolic elastance and preload-recruitable stroke work were studied as "gold standards" by using the conductance technique. PAMP was calculated with pulmonary artery flow and RV pressure measurements. Changes in these indices were compared after modulation of the inotropic state (dobutamine infusion; n = 12) and loading conditions (pulmonary artery and inferior caval vein occlusion; n = 14). All indices increased dose-dependently with dobutamine. PAMP was slightly influenced by preload reduction (the slope of the relation between PAMP and EDV was 0.00397 +/- 0.01026 W. mL(-3). 0.10(-4); mean +/- SD). PAMP decreased significantly during pulmonary artery banding (from 1.1 +/- 0.7 to 0.7 +/- 0.5 W. mL(-2). 0.10(-4); mean +/- SD), whereas end-systolic elastance and preload-recruitable stroke work did not change. We conclude that the value of PAMP as an index of RV contractility is limited in the open-chest/open-pericardium setting, primarily by its sensitivity to alterations in afterload. IMPLICATIONS Preload-adjusted maximal power (PAMP), a load-independent contractile index in the left ventricle, could offer a solution to the problem of measuring right ventricular (RV) contractility in clinical practice. However, this study in open-chest dogs suggests that PAMP is unreliable for assessment of RV contractility because of its sensitivity to afterload changes.
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Affiliation(s)
- H Alex Leather
- Center for Experimental Surgery and Anesthesiology, Anesthesiology Department, Katholieke Universiteit Leuven, Belgium
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Takagaki M, McCarthy PM, Chung M, Connor J, Dessoffy R, Ochiai Y, Howard M, Doi K, Kopcak M, Mazgalev TN, Fukamachi K. Preload-adjusted maximal power: a novel index of left ventricular contractility in atrial fibrillation. Heart 2002; 88:170-6. [PMID: 12117848 PMCID: PMC1767221 DOI: 10.1136/heart.88.2.170] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
BACKGROUND Left ventricular contractility in atrial fibrillation is known to change in a beat to beat fashion, but there is no gold standard for contractility indices in atrial fibrillation, especially those measured non-invasively. OBJECTIVE To determine whether the non-invasive index of contractility "preload-adjusted PWR(max)" (maximal ventricular power divided by the square of end diastolic volume) can accurately measure left ventricular contractility in a beat to beat fashion in atrial fibrillation. METHODS Atrial fibrillation was induced experimentally using 60 Hz stimulation of the atrium and maintained in 12 sheep; four received diltiazem, four digoxin, and four no drugs (control). Aortic flow, left ventricular volume, and left ventricular pressure were monitored simultaneously. Preload-adjusted PWR(max), the slope of the end systolic pressure-volume relation (E(max)), and the maximum rate of change of left ventricular pressure (dP/dt(max)) were calculated in a beat to beat fashion. RESULTS Preload-adjusted PWR(max) correlated linearly with load independent E(max) (p < 0.0001) and curvilinearly with load dependent dP/dt(max) (p < 0.0001), which suggested the load independence of preload-adjusted PWR(max). After five minutes of diltiazem administration, preload-adjusted PWR(max), dP/dt(max), and E(max) fell significantly (p < 0.0001) to 62%, 64%, and 61% of baseline, respectively. Changes were not significant after five minutes of digoxin (103%, 98%, and 102%) or in controls (97%, 96%, and 95%). CONCLUSIONS Preload-adjusted PWR(max) correlates linearly with E(max) and is a useful measure of contractility even in atrial fibrillation. Non-invasive application of this method, in combination with echocardiography and tonometry, may yield important information for optimising the treatment of patients with atrial fibrillation.
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Affiliation(s)
- M Takagaki
- Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, Ohio 44195, USA
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Strobeck JE. Enhanced external counterpulsation in congestive heart failure: possibly the most potent inodilator to date. CONGESTIVE HEART FAILURE (GREENWICH, CONN.) 2002; 8:201-3. [PMID: 12147942 DOI: 10.1111/j.1527-5299.2002.01743.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Senzaki H, Masutani S, Kobayashi J, Kobayashi T, Sasaki N, Asano H, Kyo S, Yokote Y, Ishizawa A. Ventricular afterload and ventricular work in fontan circulation: comparison with normal two-ventricle circulation and single-ventricle circulation with blalock-taussig shunts. Circulation 2002; 105:2885-92. [PMID: 12070118 DOI: 10.1161/01.cir.0000018621.96210.72] [Citation(s) in RCA: 122] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Recent studies have indicated that there are inherent limitations associated with Fontan physiology. However, there have been no quantitative analyses of the effects of right heart bypass on ventricular afterload, hydraulic power, and resultant overall hemodynamics. Methods and Results- During routine cardiac catheterization, aortic impedance and ventricular hydraulic power were determined, both at rest and under increased ventricular work induced by dobutamine, in 17 patients with Fontan circulation, 15 patients with a single ventricle whose pulmonary circulation was maintained only by Blalock-Taussig shunts, and 13 patients who had normal 2-ventricle circulation. Both vascular resistance (nonpulsatile load on the ventricle) and pulsatile components of ventricular afterload (represented by low-frequency impedance) were significantly higher in the Fontan group than in the other groups (P<0.01), and this was associated with decreased cardiac output in the Fontan patients. In addition, hydraulic power cost per unit forward flow was 40% lower in the 2-ventricle circulation than in the single-ventricle circulation, suggesting lower ventricular efficiency in single-ventricle circulation attributable to the lack of a pulmonary ventricle. Furthermore, in the Fontan group, beta-adrenergic reserve was markedly decreased because of a limited preload reserve. CONCLUSIONS Fontan physiology is associated with disadvantageous ventricular power and afterload profiles and has limited ventricular reserve capacity. Thus, to improve the long-term prognosis of patients after Fontan surgery, future research should be conducted into medical interventions that can overcome these limitations inherent in Fontan circulation.
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Affiliation(s)
- Hideaki Senzaki
- Department of Pediatric Cardiology, Saitama Medical School Hospital, Saitama, National Children's Hospital, Tokyo, Japan.
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Monitoring Left Heart Performance in the Critically Ill. Intensive Care Med 2002. [DOI: 10.1007/978-1-4757-5551-0_48] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Poortmans G, Schüpfer G, Roosens C, Poelaert J. Transesophageal echocardiographic evaluation of left ventricular function. J Cardiothorac Vasc Anesth 2000; 14:588-98. [PMID: 11052447 DOI: 10.1053/jcan.2000.9439] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- G Poortmans
- Postoperative Cardiac Surgical ICU and Department of Cardiac Anesthesia, Ghent University Hospital, Belgium
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Schmidlin D, Aschkenasy S, Vogt PR, Schmidli J, Jenni R, Schmid ER. Left ventricular pressure-area relations as assessed by transoesophageal echocardiographic automated border detection: comparison with conductance catheter technique in cardiac surgical patients. Br J Anaesth 2000; 85:379-88. [PMID: 11103178 DOI: 10.1093/bja/85.3.379] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The aim of this study was to validate measurements of intraoperative left ventricular (LV) area by transoesophageal echocardiography against simultaneous measurements of LV volume by conductance catheter (CC) in cardiac surgical patients with normal systolic LV function. Echo area was compared with CC volume during steady state and during acute changes of pre- and afterload by partial clamping of the inferior vena cava and the ascending aorta in eight patients scheduled for coronary artery bypass grafting. At steady state, Bland-Altman analysis of 32 recordings revealed a bias (SD) of 0.6% (2.5%) between echo area and CC volume, related to the initial values of end-diastolic area (100% area) and volume (100% volume), respectively. During loading interventions, bias between the two methods, as assessed by 112 measurement sequences, was 0.5% (3.7%) during aortic occlusion and -3.9% (4.4%) during cava occlusion at end-systole (P < 0.0001); at end-diastole, this bias was 1.3% (4%) during aortic occlusion and 0.2% (5.7%) during cava occlusion (P < 0.0001). Intraoperative area measurements with transoesophageal echocardiography in cardiac surgical patients with normal systolic LV function show good correlation with CC volume measurements under steady-state conditions. During acute unloading by vena cava occlusion, the resulting small end-systolic echo area measurements differ significantly more from CC volume measurements than during acute increase in afterload by aortic occlusion.
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Affiliation(s)
- D Schmidlin
- Institute of Anaesthesiology, University Hospital, Zurich, Switzerland
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Karunanithi MK, Feneley MP. Single-beat determination of preload recruitable stroke work relationship: derivation and evaluation in conscious dogs. J Am Coll Cardiol 2000; 35:502-13. [PMID: 10676701 DOI: 10.1016/s0735-1097(99)00566-5] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
OBJECTIVES To derive and evaluate a method of estimating the slope (Mw) of the preload recruitable stroke work (PRSW) relationship between left ventricular stroke work (SW) and end-diastolic volume (EDV) from a single beat. BACKGROUND Mw is a load-insensitive index of contractile function, but its clinical application has been limited by the need to record multiple beats over a wide volume range. METHODS Pressure-volume loops were recorded over a variable preload and afterload range by vena caval and aortic constrictions in 12 conscious dogs instrumented with epicardial dimension transducers and micromanometers. Single-beat Mw (SBMw) was determined as the ratio SW/(EDV-Vw), where the volume-axis intercept of the PRSW relationship (Vw)(EDV at zero SW) was estimated as k x EDVB + (k - 1)LVwall, k is the ratio of the epicardial shell volumes corresponding to Vw and baseline EDV (EDVB) and LVwall is wall volume. RESULTS In the first six dogs, k was found to be essentially constant at 0.7, SBMw estimates were insensitive to wide preload variation, and the relationship between SBMw and multibeat Mw determined during caval and aortic constrictions did not differ significantly from the line of identity. When the same constant k value was applied to SBMw estimation in a different group of six dogs, SBMw did not differ significantly from multibeat Mw (83 +/- 12 erg x cm(-3) x 10(3) and 77 +/- 12 erg x cm(-3) x 10(3), respectively), neither changed significantly during aortic constriction and both increased significantly with calcium infusion (107 +/- 18 erg x cm(-3) x 10(3) and 95 +/- 19 erg x cm(-3) x 10(3), respectively, both p < 0.05). Single-beat Mw was less load-dependent, more reproducible and a more sensitive index of inotropic state than two previously described single-beat indexes, single-beat elastance and maximum power divided by EDV2. CONCLUSIONS Mw can be determined accurately from a single, steady-state beat in the normal canine heart and is sensitive to inotropic alterations while being insensitive to wide variations in preload and afterload. Single-beat Mw estimation should facilitate noninvasive, load-independent assessment of contractile function.
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Affiliation(s)
- M K Karunanithi
- Victor Chang Cardiac Research Institute and Cardiology Department, St. Vincent's Hospital, Sydney, Australia
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Armstrong GP, Carlier SG, Fukamachi K, Thomas JD, Marwick TH. Estimation of cardiac reserve by peak power: validation and initial application of a simplified index. Heart 1999; 82:357-64. [PMID: 10455090 PMCID: PMC1729165 DOI: 10.1136/hrt.82.3.357] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
OBJECTIVES To validate a simplified estimate of peak power (SPP) against true (invasively measured) peak instantaneous power (TPP), to assess the feasibility of measuring SPP during exercise and to correlate this with functional capacity. DESIGN Development of a simplified method of measurement and observational study. SETTING Tertiary referral centre for cardiothoracic disease. SUBJECTS For validation of SPP with TPP, seven normal dogs and four dogs with dilated cardiomyopathy were studied. To assess feasibility and clinical significance in humans, 40 subjects were studied (26 patients; 14 normal controls). METHODS In the animal validation study, TPP was derived from ascending aortic pressure and flow probe, and from Doppler measurements of flow. SPP, calculated using the different flow measures, was compared with peak instantaneous power under different loading conditions. For the assessment in humans, SPP was measured at rest and during maximum exercise. Peak aortic flow was measured with transthoracic continuous wave Doppler, and systolic and diastolic blood pressures were derived from brachial sphygmomanometry. The difference between exercise and rest simplified peak power (Delta SPP) was compared with maximum oxygen uptake (VO(2)max), measured from expired gas analysis. RESULTS SPP estimates using peak flow measures correlated well with true peak instantaneous power (r = 0.89 to 0.97), despite marked changes in systemic pressure and flow induced by manipulation of loading conditions. In the human study, VO(2)max correlated with Delta SPP (r = 0.78) better than Delta ejection fraction (r = 0.18) and Delta rate-pressure product (r = 0.59). CONCLUSIONS The simple product of mean arterial pressure and peak aortic flow (simplified peak power, SPP) correlates with peak instantaneous power over a range of loading conditions in dogs. In humans, it can be estimated during exercise echocardiography, and correlates with maximum oxygen uptake better than ejection fraction or rate-pressure product.
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Affiliation(s)
- G P Armstrong
- Department of Cardiology, The Cleveland Clinic Foundation, Cleveland, Ohio, USA
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Abstract
Stress echocardiography is composed of a family of examinations in which various forms of cardiovascular stress are combined with echocardiographic imaging to assist in the diagnosis of coronary artery disease. Exercise cardiography has evolved over the past 20 years into a routinely available clinical tool employed in both university and community hospital settings. This article discusses advantages and disadvantages of using exercise echocardiography.
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Affiliation(s)
- E Bossone
- Cardiorespiratory Department, II University of Naples, Italy
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Gorcsan J. Load-Independent Indices of Left Ventricular Function Using Automated Border Detection. Echocardiography 1999; 16:63-76. [PMID: 11175124 DOI: 10.1111/j.1540-8175.1999.tb00787.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Echocardiographic automated border detection is the ability to assess left ventricular (LV) cross-sectional cavity areas and volumes on line. This capability has enabled the use of LV pressure-volume relationships as a means to determine LV function in a manner relatively independent of loading conditions. This discussion reviews previous validation studies in animal models and humans using LV cross-sectional area as a surrogate for LV volume and the clinical applications of LV pressure-area relations. Applications of arterial pressure as a substitute for LV ejection pressure to assess pressure-area relations are also reviewed, along with the use of pressure-area relations to assess right ventricular performance. Last, preload-adjusted maximal power as an alternative load-insensitive means to determine LV performance is discussed.
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