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Masenga SK, Kirabo A. Hypertensive heart disease: risk factors, complications and mechanisms. Front Cardiovasc Med 2023; 10:1205475. [PMID: 37342440 PMCID: PMC10277698 DOI: 10.3389/fcvm.2023.1205475] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Accepted: 05/26/2023] [Indexed: 06/22/2023] Open
Abstract
Hypertensive heart disease constitutes functional and structural dysfunction and pathogenesis occurring primarily in the left ventricle, the left atrium and the coronary arteries due to chronic uncontrolled hypertension. Hypertensive heart disease is underreported and the mechanisms underlying its correlates and complications are not well elaborated. In this review, we summarize the current understanding of hypertensive heart disease, we discuss in detail the mechanisms associated with development and complications of hypertensive heart disease especially left ventricular hypertrophy, atrial fibrillation, heart failure and coronary artery disease. We also briefly highlight the role of dietary salt, immunity and genetic predisposition in hypertensive heart disease pathogenesis.
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Affiliation(s)
- Sepiso K. Masenga
- HAND Research Group, School of Medicine and Health Sciences, Mulungushi University, Livingstone Cam-Pus, Livingstone, Zambia
- School of Medicine, University of Zambia, Lusaka, Zambia
- Department of Medicine, Vanderbilt University Medical Centre, Nashville, TN, United States
| | - Annet Kirabo
- Department of Medicine, Vanderbilt University Medical Centre, Nashville, TN, United States
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Izumida T, Imamura T, Nakamura M, Kinugawa K. Optimal Heart Rate and Prognosis in Patients with Cardiac Amyloidosis. J Cardiovasc Dev Dis 2021; 8:jcdd8120182. [PMID: 34940536 PMCID: PMC8706408 DOI: 10.3390/jcdd8120182] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Revised: 12/05/2021] [Accepted: 12/10/2021] [Indexed: 11/16/2022] Open
Abstract
Background: Optimal heart rate (HR) that associates with higher cardiac output and greater clinical outcomes in patients with cardiac amyloidosis remains unknown. Methods: Consecutive patients with sinus rhythm who were diagnosed with cardiac amyloidosis at our institute between February 2015 and February 2021 were retrospectively included. Ideal HR, at which E-wave and A-wave stand adjacent without any overlaps in the trans-mitral flow echocardiography, was calculated by the formula: 86.8−0.08 × deceleration time (msec). The association between optimal HR and cardiac death or heart failure readmission was investigated. Results: Ten patients (median 74 years old, 8 men) were included. On median, actual HR was 64 bpm and ideal HR was 69 bpm. An incidence rate of the primary endpoint in the sub-optimal HR group tended to be higher than optimal HR group: one of the four patients in optimal HR group had events (25%); two of the two patients in higher HR group had events (100%); two of the four patients in lower HR group had events (50%). Conclusions: The optimal HR was associated with greater clinical outcomes in patients with cardiac amyloidosis. The clinical impact of aggressive HR optimization in this cohort remains the next concern.
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Tagashira S, Kurose S, Kimura Y. Improvements in exercise tolerance with an exercise intensity above the anaerobic threshold in patients with acute myocardial infarction. Heart Vessels 2021; 36:766-774. [PMID: 33484291 DOI: 10.1007/s00380-020-01757-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Accepted: 12/11/2020] [Indexed: 10/22/2022]
Abstract
Anaerobic threshold (AT) from cardiopulmonary exercise tests (CPX) is the standard for measuring exercise intensity among patients with cardiovascular disease in Japan. However, it remains controversial whether AT represents the safety limit for exercise intensity in patients with cardiovascular disease. The purpose of this study was to investigate cardiac rehabilitation (CR) efficacy and safety with exercise intensities above the AT and at a traditional AT in a randomized trial. The participants included 57 patients who were admitted to the outpatient CR unit with a diagnosis of acute myocardial infarction. The participants were randomly divided as follows: 25 patients in the AT group, who performed aerobic exercises with an intensity at the AT; and 32 patients in the "Over AT" group, who performed exercises at an intensity higher than the AT. The following components were measured: maximum oxygen uptake (peak VO2), oxygen uptake at the AT (AT VO2), increase in oxygen uptake during exercise (ΔVO2/ΔWR) during the CPX, vascular endothelial function test (%FMD: the percentage of flow-mediated dilation), and isometric knee extension strength. The measurements were obtained at the start of the exercise therapy and after 2, 3, and 4 months. They were compared within and between groups, and the correlation between the rates of improvement was investigated. Peak VO2, AT VO2, ΔVO2/ΔWR, and %FMD had significantly improved after 3 months in both groups. The isometric knee extension strength had improved in the "Over AT" group after 2 months. Interactions were observed with peak VO2, ΔVO2/ΔWR, and isometric knee extension strength. However, %FMD was not significantly different between the groups. In the "Over AT" group, the rate of improvement in peak VO2 was positively correlated with the improvement in the isometric knee extension strength (r = 0.61, p < 0.001), but not with %FMD. These data suggest that exercise at an intensity above the AT improved exercise tolerance faster than that at the AT, and this improvement rate was associated with changes in isometric knee extension strength.
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Affiliation(s)
- Satoshi Tagashira
- Department of Health Science, Graduate School of Medicine, Kansai Medical University, 2-5-1 Shinmachi, Hirakata, Osaka, 573-1010, Japan. .,Department of Rehabilitation, Nozaki Tokushukai Hospital, Daito, Japan.
| | - Satoshi Kurose
- Department of Health Science, Graduate School of Medicine, Kansai Medical University, 2-5-1 Shinmachi, Hirakata, Osaka, 573-1010, Japan
| | - Yutaka Kimura
- Department of Health Science, Graduate School of Medicine, Kansai Medical University, 2-5-1 Shinmachi, Hirakata, Osaka, 573-1010, Japan
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Characterisation of LV myocardial exercise function by 2-D strain deformation imaging in elite adolescent footballers. Eur J Appl Physiol 2020; 121:239-250. [PMID: 33030575 PMCID: PMC7815563 DOI: 10.1007/s00421-020-04510-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Accepted: 09/19/2020] [Indexed: 12/15/2022]
Abstract
Purpose Few data exist on the descriptions of LV myocardial mechanics and reserve during dynamic exercise of adolescent athletes. The aim of this study was to describe the LV myocardial and cardiopulmonary changes during exercise using 2-D strain deformation imaging. Methods Elite adolescent male football players (n = 42) completed simultaneous cardiopulmonary exercise testing (CPET) and exercise echocardiography measurement of LV myocardial deformation by 2-D strain imaging. LV longitudinal and circumferential 2-D strain and strain rates were analyzed at each stage during incremental exercise to a work rate of 150 W. Additionally, exercise LV myocardial deformation and its relation to metabolic exercise parameters were evaluated at each exercise stage and in recovery using repeated measures ANOVA, linear regression and paired t tests. Results LV peak systolic baseline 2-D strain (longitudinal: − 15.4 ± 2.5%, circumferential: − 22.5 ± 3.1%) increased with each exercise stage, but longitudinal strain plateaued at 50 W (mean strain reserve − 7.8 ± 3.0) and did not significantly increase compared to subsequent exercise stages (P > 0.05), whilst circumferential strain (mean strain reserve − 11.6 ± 3.3) significantly increased (P < 0.05) throughout exercise up to 150 W as the dominant mechanism of exercise LV contractility increase. Regression analyses showed LV myocardial strain increased linearly relative to HR, VO2 and O2 pulse (P < 0.05) for circumferential deformation, but showed attenuation for longitudinal deformation. Conclusion This study describes LV myocardial deformation dynamics by 2-D strain and provides reference values for LV myocardial strain and strain rate during exercise in adolescent footballers. It found important differences between LV longitudinal and circumferential myocardial mechanics during exercise and introduces a methodology that can be used to quantify LV function and cardiac reserve during exercise in adolescent athletes.
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Gierula J, Lowry JE, Paton MF, Cole CA, Byrom R, Koshy AO, Chumun H, Kearney LC, Straw S, Bowen TS, Cubbon RM, Keenan AM, Stocken DD, Kearney MT, Witte KK. Personalized Rate-Response Programming Improves Exercise Tolerance After 6 Months in People With Cardiac Implantable Electronic Devices and Heart Failure. Circulation 2020; 141:1693-1703. [DOI: 10.1161/circulationaha.119.045066] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background:
Heart failure with reduced ejection fraction (HFrEF) is characterized by blunting of the positive relationship between heart rate and left ventricular (LV) contractility known as the force-frequency relationship (FFR). We have previously described that tailoring the rate-response programming of cardiac implantable electronic devices in patients with HFrEF on the basis of individual noninvasive FFR data acutely improves exercise capacity. We aimed to examine whether using FFR data to tailor heart rate response in patients with HFrEF with cardiac implantable electronic devices favorably influences exercise capacity and LV function 6 months later.
Methods:
We conducted a single-center, double-blind, randomized, parallel-group trial in patients with stable symptomatic HFrEF taking optimal guideline-directed medical therapy and with a cardiac implantable electronic device (cardiac resynchronization therapy or implantable cardioverter-defibrillator). Participants were randomized on a 1:1 basis between tailored rate-response programming on the basis of individual FFR data and conventional age-guided rate-response programming. The primary outcome measure was change in walk time on a treadmill walk test. Secondary outcomes included changes in LV systolic function, peak oxygen consumption, and quality of life.
Results:
We randomized 83 patients with a mean±SD age 74.6±8.7 years and LV ejection fraction 35.2±10.5. Mean change in exercise time at 6 months was 75.4 (95% CI, 23.4 to 127.5) seconds for FFR-guided rate-adaptive pacing and 3.1 (95% CI, −44.1 to 50.3) seconds for conventional settings (analysis of covariance;
P
=0.044 between groups) despite lower peak mean±SD heart rates (98.6±19.4 versus 112.0±20.3 beats per minute). FFR-guided heart rate settings had no adverse effect on LV structure or function, whereas conventional settings were associated with a reduction in LV ejection fraction.
Conclusions:
In this phase II study, FFR-guided rate-response programming determined using a reproducible, noninvasive method appears to improve exercise time and limit changes to LV function in people with HFrEF and cardiac implantable electronic devices. Work is ongoing to confirm our findings in a multicenter setting and on longer-term clinical outcomes.
Registration:
URL:
https://www.clinicaltrials.gov
; Unique identifier: NCT02964650.
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Affiliation(s)
- John Gierula
- Leeds Institute of Cardiovascular and Metabolic Medicine (J.G., J.E.L., M.F.P., C.A.C., R.B., A.O.K., H.C., L.C.K., S.S., R.M.C., M.T.K., K.K.W.), University of Leeds, United Kingdom
| | - Judith E. Lowry
- Leeds Institute of Cardiovascular and Metabolic Medicine (J.G., J.E.L., M.F.P., C.A.C., R.B., A.O.K., H.C., L.C.K., S.S., R.M.C., M.T.K., K.K.W.), University of Leeds, United Kingdom
| | - Maria F. Paton
- Leeds Institute of Cardiovascular and Metabolic Medicine (J.G., J.E.L., M.F.P., C.A.C., R.B., A.O.K., H.C., L.C.K., S.S., R.M.C., M.T.K., K.K.W.), University of Leeds, United Kingdom
| | - Charlotte A. Cole
- Leeds Institute of Cardiovascular and Metabolic Medicine (J.G., J.E.L., M.F.P., C.A.C., R.B., A.O.K., H.C., L.C.K., S.S., R.M.C., M.T.K., K.K.W.), University of Leeds, United Kingdom
| | - Rowenna Byrom
- Leeds Institute of Cardiovascular and Metabolic Medicine (J.G., J.E.L., M.F.P., C.A.C., R.B., A.O.K., H.C., L.C.K., S.S., R.M.C., M.T.K., K.K.W.), University of Leeds, United Kingdom
| | - Aaron O. Koshy
- Leeds Institute of Cardiovascular and Metabolic Medicine (J.G., J.E.L., M.F.P., C.A.C., R.B., A.O.K., H.C., L.C.K., S.S., R.M.C., M.T.K., K.K.W.), University of Leeds, United Kingdom
| | - Hemant Chumun
- Leeds Institute of Cardiovascular and Metabolic Medicine (J.G., J.E.L., M.F.P., C.A.C., R.B., A.O.K., H.C., L.C.K., S.S., R.M.C., M.T.K., K.K.W.), University of Leeds, United Kingdom
| | - Lorraine C. Kearney
- Leeds Institute of Cardiovascular and Metabolic Medicine (J.G., J.E.L., M.F.P., C.A.C., R.B., A.O.K., H.C., L.C.K., S.S., R.M.C., M.T.K., K.K.W.), University of Leeds, United Kingdom
| | - Sam Straw
- Leeds Institute of Cardiovascular and Metabolic Medicine (J.G., J.E.L., M.F.P., C.A.C., R.B., A.O.K., H.C., L.C.K., S.S., R.M.C., M.T.K., K.K.W.), University of Leeds, United Kingdom
| | - T. Scott Bowen
- Faculty of Biological Sciences, School of Medicine (T.S.B.), University of Leeds, United Kingdom
| | - Richard M. Cubbon
- Leeds Institute of Cardiovascular and Metabolic Medicine (J.G., J.E.L., M.F.P., C.A.C., R.B., A.O.K., H.C., L.C.K., S.S., R.M.C., M.T.K., K.K.W.), University of Leeds, United Kingdom
| | | | - Deborah D. Stocken
- Leeds Institute of Clinical Trials Research (D.D.S), University of Leeds, United Kingdom
| | - Mark T. Kearney
- Leeds Institute of Cardiovascular and Metabolic Medicine (J.G., J.E.L., M.F.P., C.A.C., R.B., A.O.K., H.C., L.C.K., S.S., R.M.C., M.T.K., K.K.W.), University of Leeds, United Kingdom
| | - Klaus K. Witte
- Leeds Institute of Cardiovascular and Metabolic Medicine (J.G., J.E.L., M.F.P., C.A.C., R.B., A.O.K., H.C., L.C.K., S.S., R.M.C., M.T.K., K.K.W.), University of Leeds, United Kingdom
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Gierula J, Paton MF, Lowry JE, Jamil HA, Byrom R, Drozd M, Garnham JO, Cubbon RM, Cairns DA, Kearney MT, Witte KK. Rate-Response Programming Tailored to the Force-Frequency Relationship Improves Exercise Tolerance in Chronic Heart Failure. JACC-HEART FAILURE 2018; 6:105-113. [DOI: 10.1016/j.jchf.2017.09.018] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Revised: 08/31/2017] [Accepted: 09/10/2017] [Indexed: 01/09/2023]
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Vela-Guajardo JE, Pérez-Treviño P, Rivera-Álvarez I, González-Mondellini FA, Altamirano J, García N. The 8-oxo-deoxyguanosine glycosylase increases its migration to mitochondria in compensated cardiac hypertrophy. ACTA ACUST UNITED AC 2017; 11:660-672. [PMID: 28882450 DOI: 10.1016/j.jash.2017.08.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Revised: 06/30/2017] [Accepted: 08/15/2017] [Indexed: 11/19/2022]
Abstract
Cardiac hypertrophy is a compensatory mechanism maladapted because it presents an increase in the oxidative stress which could be associated with the development of the heart failure. A mechanism proposed is by mitochondrial DNA (mtDNA) oxidation, which evolved to a vicious cycle because of the synthesis of proteins encoded in the genome is committed. Therefore, the aim of the present work was to evaluate the mtDNA damage and enzyme repairing the 8-oxo-deoxyguanosine glycosylase mitochondrial isoform 1-2a (OGG1-2a) in the early stage of compensated cardiac hypertrophy induced by abdominal aortic constriction (AAC). Results showed that after 6 weeks of AAC, hearts presented a compensated hypertrophy (22%), with an increase in the cell volume (35%), mitochondrial mass (12%), and mitochondrial membrane potential (94%). However, the increase of oxidative stress did not affect mtDNA most probably because OGG1-2a was found to increase 3.2 times in the mitochondrial fraction. Besides, mitochondrial function was not altered by the cardiac hypertrophy condition but in vitro mitochondria from AAC heart showed an increased sensibility to stress induced by the high Ca2+ concentration. The increase in the oxidative stress in compensated cardiac hypertrophy induced the OGG1-2a migration to mitochondria to repair mtDNA oxidation, as a mechanism that allows maintaining the cardiac function in the compensatory stage.
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Affiliation(s)
- Jorge E Vela-Guajardo
- Medicina Cardiovascular y Metabolómica, Tecnologico de Monterrey, Escuela de Medicina y Ciencias de la Salud, San Pedro Garza García, Nuevo León, México
| | - Perla Pérez-Treviño
- Medicina Cardiovascular y Metabolómica, Tecnologico de Monterrey, Escuela de Medicina y Ciencias de la Salud, San Pedro Garza García, Nuevo León, México
| | - Irais Rivera-Álvarez
- Medicina Cardiovascular y Metabolómica, Tecnologico de Monterrey, Escuela de Medicina y Ciencias de la Salud, San Pedro Garza García, Nuevo León, México
| | - Fabio A González-Mondellini
- Medicina Cardiovascular y Metabolómica, Tecnologico de Monterrey, Escuela de Medicina y Ciencias de la Salud, San Pedro Garza García, Nuevo León, México
| | - Julio Altamirano
- Medicina Cardiovascular y Metabolómica, Tecnologico de Monterrey, Escuela de Medicina y Ciencias de la Salud, San Pedro Garza García, Nuevo León, México
| | - Noemí García
- Medicina Cardiovascular y Metabolómica, Tecnologico de Monterrey, Escuela de Medicina y Ciencias de la Salud, San Pedro Garza García, Nuevo León, México.
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Pieles GE, Gowing L, Forsey J, Ramanujam P, Miller F, Stuart AG, Williams CA. The relationship between biventricular myocardial performance and metabolic parameters during incremental exercise and recovery in healthy adolescents. Am J Physiol Heart Circ Physiol 2015; 309:H2067-76. [PMID: 26475589 DOI: 10.1152/ajpheart.00627.2015] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Accepted: 10/08/2015] [Indexed: 12/18/2022]
Abstract
Background left ventricular (LV) and right ventricular (RV) myocardial reserve during exercise in adolescents has not been directly characterized. The aim of this study was to quantify myocardial performance response to exercise by using two-dimensional (2-D) speckle tracking echocardiography and describe the relationship between myocardial reserve, respiratory, and metabolic exercise parameters. A total of 23 healthy boys and girls (mean age 13.2 ± 2.7 yr; stature 159.1 ± 16.4 cm; body mass 49.5 ± 16.6 kg; BSA 1.47 ± 0.33 m(2)) completed an incremental cardiopulmonary exercise test (25 W · 3 min increments) with simultaneous acquisition of 2-D transthoracic echocardiography at rest, each exercise stage up to 100 W, and in recovery at 2 min and 10 min. Two-dimensional LV (LV Sl) and RV (RV Sl) longitudinal strain and LV circumferential strain (LV Sc) were analyzed to define the relationship between myocardial performance reserve and metabolic exercise parameters. Participants achieved a peak oxygen uptake (V̇o 2peak) of 40.6 ± 8.9 ml · kg(-1) · min(-1) and a work rate of 154 ± 42 W. LV Sl and LV Sc and RV Sl increased significantly across work rates (P < 0.05). LV Sl during exercise was significantly correlated to resting strain, V̇o 2peak, oxygen pulse, and work rate (0.530 ≤ r ≤ 0.784, P < 0.05). This study identifies a positive and moderate relationship between LV and RV myocardial performance and metabolic parameters during exercise by using a novel methodology. Relationships detected present novel data directly describing myocardial adaptation at different stages of exercise and recovery that in the future can help directly assess cardiac reserve in patients with cardiac pathology.
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Affiliation(s)
- Guido E Pieles
- Bristol Congenital Heart Centre, The Bristol Heart Institute, University Hospitals, Bristol NHS Foundation Trust, and National Institute for Health Research Cardiovascular Biomedical, Research Unit, Bristol Heart Institute, Bristol, United Kingdom
| | - Lucy Gowing
- Children's Health and Exercise Research Centre, University of Exeter, Exeter, United Kingdom
| | - Jonathan Forsey
- Bristol Congenital Heart Centre, The Bristol Heart Institute, University Hospitals, Bristol NHS Foundation Trust, and
| | - Paramanantham Ramanujam
- Children's Health and Exercise Research Centre, University of Exeter, Exeter, United Kingdom
| | - Felicity Miller
- Children's Health and Exercise Research Centre, University of Exeter, Exeter, United Kingdom
| | - A Graham Stuart
- Bristol Congenital Heart Centre, The Bristol Heart Institute, University Hospitals, Bristol NHS Foundation Trust, and
| | - Craig A Williams
- Children's Health and Exercise Research Centre, University of Exeter, Exeter, United Kingdom
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Sugiura Kojima M, Noda A, Miyata S, Kojima J, Hara Y, Minoshima M, Murohara T. The Effect of Habitual Physical Training on Left Ventricular Function During Exercise Assessed by Three-Dimensional Echocardiography. Echocardiography 2015; 32:1670-5. [PMID: 25817077 DOI: 10.1111/echo.12934] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND Stroke volume (SV) in trained athletes continuously increases with progressive exercise intensity. We studied whether physical training affected left ventricle (LV) function response to exercise using 3D echocardiography and tissue Doppler imaging (TDI). METHODS Eleven male university athletes and 12 male university nonathletes were enrolled in this study. After baseline data were collected, subjects performed a symptom-limited supine bicycle ergometer exercise test. Initial workload was 25 Watts (W) and increased 25 W every 3 minutes. At rest and every exercise stage, LV end-systolic and diastolic volume index (LVEDVI and LVESVI), SV index (SVI), cardiac index (CI), LV ejection fraction (LVEF), and early lateral mitral flow velocity (Ea) were evaluated. Heart rate (HR), and systolic and diastolic blood pressure (SBP and DBP) were continuously recorded. RESULTS Nonathletes showed a slow increase in CI, and SVI reached a plateau value at a HR of 90 beats per minute (bpm). In contrast, CI and SVI increased progressively and continuously in athletes. Both CI and SVI were significantly higher in athletes than in nonathletes at HRs of 100, 110, and 120 bpm. LVEDVI kept increasing in athletes while it plateaued in nonathletes. In contrast, LVESV decreased continuously during exercise in both groups. There was no significant difference in LVEF, Ea, SBP, or DBP at rest and during exercise between the two groups. CONCLUSION LV responses to exercise in athletes were different from those of in nonathletes; thus, habitual physical training may play an important role in the increase in both SVI and CI in young individuals.
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Affiliation(s)
| | - Akiko Noda
- Department of Biomedical Sciences, Chubu University, Kasugai, Japan
| | - Seiko Miyata
- Department of Biomedical Sciences, Chubu University, Kasugai, Japan
| | - Jun Kojima
- Nagoya University School of Health Sciences, Nagoya, Japan
| | - Yuki Hara
- Nagoya University School of Health Sciences, Nagoya, Japan
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10
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Bombardini T, Zoppè M, Ciampi Q, Cortigiani L, Agricola E, Salvadori S, Loni T, Pratali L, Picano E. Myocardial contractility in the stress echo lab: from pathophysiological toy to clinical tool. Cardiovasc Ultrasound 2013; 11:41. [PMID: 24246005 PMCID: PMC3875530 DOI: 10.1186/1476-7120-11-41] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2013] [Accepted: 11/15/2013] [Indexed: 11/10/2022] Open
Abstract
Up-regulation of Ca2+ entry through Ca2+ channels by high rates of beating is involved in the frequency-dependent regulation of contractility: this process is crucial in adaptation to exercise and stress and is universally known as force-frequency relation (FFR). Disturbances in calcium handling play a central role in the disturbed contractile function in myocardial failure. Measurements of twitch tension in isolated left-ventricular strips from explanted cardiomyopathic hearts compared with non-failing hearts show flat or biphasic FFR, while it is up-sloping in normal hearts. Starting in 2003 we introduced the FFR measurement in the stress echo lab using the end-systolic pressure (ESP)/End-systolic volume index (ESVi) ratio (the Suga index) at increasing heart rates. We studied a total of 2,031 patients reported in peer-reviewed journals: 483 during exercise, 34 with pacing, 850 with dobutamine and 664 during dipyridamole stress echo. We demonstrated the feasibility of FFR in the stress echo lab, the clinical usefulness of FFR for diagnosing latent contractile dysfunction in apparently normal hearts, and residual contractile reserve in dilated idiopathic and ischemic cardiomyopathy. In 400 patients with left ventricular dysfunction (ejection fraction 30 ± 9%) with negative stress echocardiography results, event-free survival was higher (p < 0.001) in patients with ΔESPVR (the difference between peak and rest end-systolic pressure-volume ratio, ESPVR) ≥ 0.4 mmHg/mL/m2. The prognostic stratification of patients was better with FFR, beyond the standard LV ejection fraction evaluation, also in the particular settings of severe mitral regurgitation or diabetics without stress-induced ischemia. In the particular setting of selection of heart transplant donors, the stress echo FFR was able to correctly select 34 marginal donor hearts efficiently transplanted in emergency recipients. Starting in 2007, we introduced an operator-independent cutaneous sensor to monitor the FFR: the force is quantified as the sensed pre-ejection myocardial vibration amplitude. We demonstrated that the sensor-derived force changes at increasing heart rates are highly related with both max dP/dt in animal models, and with the stress echo FFR in 220 humans, opening a new window for pervasive cardiac heart failure monitoring in telemedicine systems.
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Affiliation(s)
- Tonino Bombardini
- CNR, Institute of Clinical Physiology, Area della Ricerca, Pisa 56124, Italy.
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11
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Schmidt MR, White PA, Khambadkone S, Gross GJ, Bøtker HE, Vogel M, Hjortdal VE, Sørensen KE, Redington AN. The neonatal but not the mature heart adapts to acute tachycardia by beneficial modification of the force-frequency relationship. Pediatr Cardiol 2011; 32:562-7. [PMID: 21394656 DOI: 10.1007/s00246-011-9899-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/07/2008] [Accepted: 01/31/2011] [Indexed: 10/18/2022]
Abstract
The force-frequency relationship (FFR) reflects alterations in intracellular calcium cycling during changing heart rate (HR). Tachycardia-induced heart failure is associated with depletion of intracellular calcium. We hypothesized (1) that the relative resistance to tachycardia-induced heart failure seen in neonatal pigs is related to differences in calcium cycling, resulting in different FFR responses and (2) that pretreatment with digoxin to increase intracellular calcium would modifies these changes. LV +dP/dt was measured during incremental right atrial pacing in 16 neonatal and 14 adult pigs. FFR was measured as the change in +dP/dt as HR was increased. Animals were randomized to control or intravenous bolus digoxin (n = 8 neonate pigs in the 0.05 mg/kg group and n = 7 adult pigs in the 0.025 mg/kg group) and paced for 90 min at 25 bpm greater than the rate of peak +dP/dt. Repeat FFR was then obtained. The postpacing FFR in neonatal control pigs shifted rightward, with peak force occurring 30 bpm greater than baseline (P < 0.03). There was no vertical shift; thus, force at 150 bpm decreased (P < 0.03) and force at 300 beats/min increased (P < 0.08). In adult control pigs, FFR shifted downward (P < 0.01), with decreased force generation at all HRs. In both neonates and adult pigs, digoxin increased +dP/dt at all HRs; however, in neonate pigs digoxin decreased the contractile reserve by abrogation of the rightward shift of FFR. An adaptive response to tachycardia in the neonate pig leads to improved force generation at greater HRs. Conversely, the response of the mature pig heart is maladaptive with decreased force generation. Pretreatment with digoxin modifies these responses.
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Affiliation(s)
- M R Schmidt
- Aarhus University Hospital, Skejby Sygehus, Aarhus, Denmark.
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GEMIGNANI VINCENZO, BIANCHINI ELISABETTA, FAITA FRANCESCO, LIONETTI VINCENZO, CAMPAN MANUELA, RECCHIA FABIOANASTASIO, PICANO EUGENIO, BOMBARDINI TONINO. Transthoracic Sensor for Noninvasive Assessment of Left Ventricular Contractility: Validation in A Minipig Model of Chronic Heart Failure. PACING AND CLINICAL ELECTROPHYSIOLOGY: PACE 2010; 33:795-803. [DOI: 10.1111/j.1540-8159.2009.02684.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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13
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Unno K, Isobe S, Izawa H, Cheng XW, Kobayashi M, Hirashiki A, Yamada T, Harada K, Ohshima S, Noda A, Nagata K, Kato K, Yokota M, Murohara T. Relation of functional and morphological changes in mitochondria to myocardial contractile and relaxation reserves in asymptomatic to mildly symptomatic patients with hypertrophic cardiomyopathy. Eur Heart J 2009; 30:1853-62. [DOI: 10.1093/eurheartj/ehp184] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Bombardini T, Gemignani V, Bianchini E, Pasanisi E, Pratali L, Pianelli M, Faita F, Giannoni M, Arpesella G, Sicari R, Picano E. Post-exercise contractility, diastolic function, and pressure: operator-independent sensor-based intelligent monitoring for heart failure telemedicine. Cardiovasc Ultrasound 2009; 7:21. [PMID: 19442285 PMCID: PMC2689191 DOI: 10.1186/1476-7120-7-21] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2009] [Accepted: 05/14/2009] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND New sensors for intelligent remote monitoring of the heart should be developed. Recently, a cutaneous force-frequency relation recording system has been validated based on heart sound amplitude and timing variations at increasing heart rates. AIM To assess sensor-based post-exercise contractility, diastolic function and pressure in normal and diseased hearts as a model of a wireless telemedicine system. METHODS We enrolled 150 patients and 22 controls referred for exercise-stress echocardiography, age 55 +/- 18 years. The sensor was attached in the precordial region by an ECG electrode. Stress and recovery contractility were derived by first heart sound amplitude vibration changes; diastolic times were acquired continuously. Systemic pressure changes were quantitatively documented by second heart sound recording. RESULTS Interpretable sensor recordings were obtained in all patients (feasibility = 100%). Post-exercise contractility overshoot (defined as increase > 10% of recovery contractility vs exercise value) was more frequent in patients than controls (27% vs 8%, p < 0.05). At 100 bpm stress heart rate, systolic/diastolic time ratio (normal, < 1) was > 1 in 20 patients and in none of the controls (p < 0.01); at recovery systolic/diastolic ratio was > 1 in only 3 patients (p < 0.01 vs stress). Post-exercise reduced arterial pressure was sensed. CONCLUSION Post-exercise contractility, diastolic time and pressure changes can be continuously measured by a cutaneous sensor. Heart disease affects not only exercise systolic performance, but also post-exercise recovery, diastolic time intervals and blood pressure changes--in our study, all of these were monitored by a non-invasive wearable sensor.
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Affiliation(s)
- Tonino Bombardini
- Department of Echocardiography Lab, Institute of Clinical Physiology, National Council of Research, Pisa, Italy.
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Restoration of cardiac function by setting the ventricular pacing at a lower range in an infant with congenital complete atrioventricular block and dilated cardiomyopathy. Int J Cardiol 2008; 131:e38-40. [DOI: 10.1016/j.ijcard.2007.07.061] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/20/2007] [Accepted: 07/07/2007] [Indexed: 11/17/2022]
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Bombardini T, Galderisi M, Agricola E, Coppola V, Mottola G, Picano E. Negative stress echo: Further prognostic stratification with assessment of pressure–volume relation. Int J Cardiol 2008; 126:258-67. [PMID: 17509703 DOI: 10.1016/j.ijcard.2006.12.093] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2006] [Revised: 10/25/2006] [Accepted: 12/30/2006] [Indexed: 10/23/2022]
Abstract
BACKGROUND A maximal negative stress echo identifies a low risk for subsequent hard events subset. However, the potentially prognostically relevant information on global contractile reserve on the left ventricle is missed by standard regional wall motion assessment, and can be obtained by end-systolic pressure-volume relationship (PVR) evaluation. AIM To assess the relative prognostic value of PVR in patients with negative stress echo. METHODS We enrolled 99 consecutive patients (age=61+/-14 years; 81 males, LVEF 47+/-14%, WMSI=1.42+/-0.50) with negative exercise stress echo for standard wall motion criteria. To build the PVR, the force was determined at rest and peak stress as the ratio of the systolic pressure/end-systolic volume index. All patients were followed-up on medical therapy. RESULTS Median follow-up was 21 months (interquartile range 12-26). Twenty-nine events have been observed: 6 deaths, 10 heart failure related hospitalization and 13 worsening NYHA class of >or=1 grade. Using Cox's proportional hazard model the best independent predictor of total events was SP/ESV index change (rest-stress) <1.5 mm Hg/ml/m(2) as determined by ROC analysis cut-off (RR=29, p=0.001, sensitivity=80%, specificity=93%). The overall survival and event-free survival was 34% in patients with change (rest-stress) SP/ESV index<1.5 mm Hg/ml/m(2) and 97% in whose with >1.5 mm Hg/ml/m(2). CONCLUSIONS In patients with negative stress echo, a preserved global contractility response can be easily identified through stress-induced variation in SP/ESV index, with powerful further risk stratification.
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Affiliation(s)
- T Bombardini
- CNR, Institute of Clinical Physiology, Via Moruzzi 1, 56124 Pisa, Italy.
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17
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Bombardini T, Gemignani V, Bianchini E, Venneri L, Petersen C, Pasanisi E, Pratali L, Pianelli M, Faita F, Giannoni M, Picano E. Cardiac reflections and natural vibrations: force-frequency relation recording system in the stress echo lab. Cardiovasc Ultrasound 2007; 5:42. [PMID: 18031588 PMCID: PMC2221800 DOI: 10.1186/1476-7120-5-42] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2007] [Accepted: 11/22/2007] [Indexed: 11/18/2022] Open
Abstract
Background The inherent ability of ventricular myocardium to increase its force of contraction in response to an increase in contraction frequency is known as the cardiac force-frequency relation (FFR). This relation can be easily obtained in the stress echo lab, where the force is computed as the systolic pressure/end-systolic volume index ratio, and measured for increasing heart rates during stress. Ideally, the noninvasive, imaging independent, objective assessment of FFR would greatly enhance its practical appeal. Objectives 1 – To evaluate the feasibility of the cardiac force measurement by a precordial cutaneous sensor. 2 – To build the curve of force variation as a function of the heart rate. 3 – To compare the standard stress echo results vs. this sensor operator-independent built FFR. Methods The transcutaneous force sensor was positioned in the precordial region in 88 consecutive patients referred for exercise, dipyridamole, or pacing stress. The force was measured as the myocardial vibrations amplitude in the isovolumic contraction period. FFR was computed as the curve of force variation as a function of heart rate. Standard echocardiographic FFR measurements were performed. Results A consistent FFR was obtained in all patients. Both the sensor built and the echo built FFR identifiy pts with normal or abnormal contractile reserve. The best cut-off value of the sensor built FFR was 15.5 g * 10-3 (Sensitivity = 0.85, Specificity = 0.77). Sensor built FFR slope and shape mirror pressure/volume relation during stress. This approach is extendable to daily physiological exercise and could be potentially attractive in home monitoring systems.
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Ciampi Q, Villari B. Role of echocardiography in diagnosis and risk stratification in heart failure with left ventricular systolic dysfunction. Cardiovasc Ultrasound 2007; 5:34. [PMID: 17910744 PMCID: PMC2064911 DOI: 10.1186/1476-7120-5-34] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2007] [Accepted: 10/02/2007] [Indexed: 01/13/2023] Open
Abstract
Heart failure (HF) is a complex clinical syndrome that can result from any structural or functional cardiac disorder that impairs the ability of the ventricle to fill with or eject blood. Echocardiography represents the "gold standard" in the assessment of LV systolic dysfunction and in the recognition of systolic heart failure, since dilatation of the LV results in alteration of intracardiac geometry and hemodynamics leading to increased morbidity and mortality. The functional mitral regurgitation is a consequence of adverse LV remodelling that occurs with a structurally normal valve and it is a marker of adverse prognosis. Diastolic dysfunction plays a major role in signs and symptoms of HF and in the risk stratification, and provides prognostic information independently in HF patients and impaired systolic function. Ultrasound lung comets are a simple echographic sign of extravascular lung water, more frequently associated with left ventricular diastolic and/or systolic dysfunction, which can integrate the clinical and pathophysiological information provided by conventional echocardiography and provide a useful information for prognostic stratification of HF patients. Contractile reserve is defined as the difference between values of an index of left ventricular contractility during peak stress and its baseline values and the presence of myocardial viability predicts a favorable outcome. A non-invasive echocardiographic method for the evaluation of force-frequency relationship has been proposed to assess the changes in contractility during stress echo. In conclusion, in HF patients, the evaluation of systolic, diastolic function and myocardial contractile reserve plays a fundamental role in the risk stratification. The highest risk is present in HF patients with a heart that is weak, big, noisy, stiff and wet.
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Affiliation(s)
- Quirino Ciampi
- Division of Cardiology, Fatebenefratelli Hospital, Benevento, Italy
| | - Bruno Villari
- Division of Cardiology, Fatebenefratelli Hospital, Benevento, Italy
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Yamanaka T, Onishi K, Tanabe M, Dohi K, Funabiki-Yamanaka K, Fujimoto N, Kurita T, Tanigawa T, Kitamura T, Ito M, Nobori T, Nakano T. Force- and relaxation-frequency relations in patients with diastolic heart failure. Am Heart J 2006; 152:966.e1-7. [PMID: 17070168 DOI: 10.1016/j.ahj.2006.06.023] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/26/2005] [Accepted: 06/07/2006] [Indexed: 01/19/2023]
Abstract
BACKGROUND Chronotropic effects on myocardial contractility (the positive force-frequency relation) and relaxation (the positive relaxation-frequency relation) are impaired in patients with congestive heart failure and depressed left ventricular (LV) ejection fraction (systolic heart failure [SHF]). However, the force- and relaxation-frequency relation and LV-arterial coupling in patients with diastolic heart failure (DHF) has not been fully investigated. METHODS AND RESULTS To examine inotropic and lusitropic responsiveness to atrial pacing, LV pressure-volume relations were measured using a conductance catheter and microtip manometer in patients with DHF (n = 18) and SHF (n = 11). In patients with SHF, an increase in heart rate by 40 beat/min did not affect LV end-systolic elastance (Ees), which reflects LV contractility, or the time constant of LV relaxation. By contrast, in patients with DHF, an increase in heart rate by 40 beat/min significantly enhanced Ees (2.1 vs 2.9 mm Hg/mL, P < .05) but not the time constant. Furthermore, LV-arterial coupling, quantified as Ees/arterial elastance, was impaired during pacing in patients with DHF (1.1 vs 0.8, P < .05) as well as SHF. CONCLUSIONS In patients with DHF, the force-frequency relation was preserved, but the relaxation-frequency relation was impaired. Furthermore, LV-arterial coupling was impaired as heart rate increased, which may be related to the impaired LV function. These results suggest that the impaired relaxation-frequency relation and exacerbated LV-arterial coupling during tachycardia may be an important therapeutic target in patients with DHF.
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Affiliation(s)
- Takashi Yamanaka
- The First Department of Internal Medicine, Mie University School of Medicine, Tsu, Japan
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Pereira NL, Zile MR, Harley RA, Van Bakel AB. Myocardial Mechanisms Causing Heart Failure Early After Cardiac Transplantation. Transplant Proc 2006; 38:2999-3003. [PMID: 17112884 DOI: 10.1016/j.transproceed.2006.08.117] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2006] [Indexed: 10/23/2022]
Abstract
Early after heart transplantation, some patients have heart failure (HF) with preserved left ventricular ejection fraction (LVEF), in the absence of rejection. The purpose of this study was to define the mechanisms causing HF early after transplantation and to determine whether these mechanisms involve changes that occur in active or passive myocardial properties. Eleven consecutive patients 1 week after heart transplantation underwent right heart catheterization and echocardiography with an endomyocardial biopsy. Hemodynamic measurements were obtained at spontaneous heart rate, and then were repeated at three atrially paced rates increased in 20-bpm increments above spontaneous heart rate. At baseline, 5 patients (group 1) had clinical HF and a pulmonary capillary wedge pressure (PCWP) > or = 16 mmHg, and 6 patients (group 2) had no clinical evidence of HF and a PCWP < 16 mmHg. LVEF was normal in all 11 patients. The relationships between cardiac index versus heart rate (HR) and PCWP versus HR were normal in all 11 patients. These normal function-versus-frequency relationships suggested that there were no significant abnormalities in the active myocardial processes of contraction or relaxation. In group 1 patients, the PCWP was significantly increased but the left ventricular end diastolic dimension was normal, suggestive of diastolic stiffness. Early after transplantation, there was a significant increase in LV wall thickness in group 1 patients as compared with preexplantation values despite myocardial biopsies in all 11 patients, showing no evidence of rejection, cardiomyocyte hypertrophy, or interstitial fibrosis thus suggestive of myocardial edema.
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Affiliation(s)
- N L Pereira
- Department of Medicine, Medical University of South Carolina, Charleston, South Carolina 29425, USA.
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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: 102] [Impact Index Per Article: 5.7] [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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Lin MS, Lin JL, Liu YB, Wu CC, Lin LC, Chen MF. Immediate impairment of left ventricular mechanical performance and force–frequency relation by rate-responsive dual-chamber, but not atrial pacing: Implications from intraventricular isovolumic relaxation flow. Int J Cardiol 2006; 109:367-74. [PMID: 16054251 DOI: 10.1016/j.ijcard.2005.06.055] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2005] [Revised: 06/09/2005] [Accepted: 06/11/2005] [Indexed: 11/25/2022]
Abstract
BACKGROUND Despite the maintenance of atrioventricular (AV) synchrony, the detrimental effect of left ventricular asynchronization on mechanical performance and intraventricular flow by nonphysiologic right ventricular apical pacing in dual-chamber pacing, with and without rate adaptation, is not clear. METHOD Twenty-seven consecutive patients receiving permanent pacemakers for symptomatic bradyarrhythmias (18 with DDD and 9 with AAI mode pacemakers) were evaluated with standard and tissue Doppler echocardiography before and 24 h after pacemaker implantation. The rate-response effect of pacing was studied by programmed rate with increments of 20, from 60 to 100/min. RESULTS Color M-mode echocardiography demonstrated that much more DDD patients developed new biphasic intraventricular flow during isovolumic relaxation period than AAI patients (13/18 versus 0/9, P<0.001). In DDD patients, the ventricular relaxation represented by mitral annulus velocity in early diastole significantly attenuated (before vs. after DDDR, 8.5+/-2.8 vs. 5.2+/-1.2 cm/s, P<0.05), and also the mitral flow propagation velocity (33+/-11 vs. 25+/-5 cm/s, P<0.01). The myocardial performance index increased after DDD (0.70+/-0.15 vs. 0.79+/-0.24, P<0.05) but not after AAI (0.61+/-0.1 vs. 0.59+/-0.08, P=NS). For both pacing groups, the accelerated pacing rate prolonged the isovolumic relaxation time and shortened the diastole period (P<0.001). However, only DDD patients had a decreased mitral flow propagation velocity (P=0.026) and an attenuated force-frequency relation in programmed rate acceleration. CONCLUSION Despite the AV synchrony, right ventricular apical pacing immediately attenuates the left ventricular contraction and relaxation performance, which deteriorated further and suppressed the physiologically positive force-frequency relation after accelerated pacing rate.
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Affiliation(s)
- Mao-Shin Lin
- Division of Cardiology, Department of Internal Medicine, National Taiwan University Hospital, No. 7, Chung-Shan South Road, Taipei 10016, Taiwan
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Abstract
Background High-rate pacing is a valid stress test to be used in conjunction with echocardiography; it is independent of physical exercise and does not require drug administration. There are two main applications of pacing stress in the echo lab: the noninvasive detection of coronary artery disease through induction of a regional transient dysfunction; and the assessment of contractile reserve through peak systolic pressure/ end-systolic volume relationship at increasing heart rates to assess global left ventricular contractility. Methods The pathophysiologic rationale of pacing stress for noninvasive detection of coronary artery disease is obvious, with the stress determined by a controlled increase in heart rate, which is a major determinant of myocardial oxygen demand, and thereby tachycardia may exceed a fixed coronary flow reserve in the presence of hemodynamically significant coronary artery disease. The use of pacing stress echo to assess left ventricular contractile reserve is less established, but promising. Positive inotropic interventions are mirrored by smaller end-systolic volumes and higher end-systolic pressures. An increased heart rate progressively increases the force of ventricular contraction (Bowditch treppe or staircase phenomenon). To build the force-frequency relationship, the force is determined at different heart rate steps as the ratio of the systolic pressure (cuff sphygmomanometer)/end-systolic volume index (biplane Simpson rule). The heart rate is determined from ECG. Conclusion Two-dimensional echocardiography during pacing is a useful tool in the detection of coronary artery disease. Because of its safety and ease of repeatability noninvasive pacing stress echo can be the first-line stress test in patients with permanent pacemaker. The force-frequency can be defined as up- sloping (normal) when the peak stress pacing systolic pressure/end-systolic volume index is higher than baseline and intermediate stress values, biphasic with an initial up- sloping followed by a later down-sloping trend, or flat or negative when peak stress pacing systolic pressure/end-systolic volume index is equal or lower than baseline stress values. This approach is certainly highly feasible and allows a conceptually immaculate definition of contractility with prognostic usefulness, but its therapeutic implications remains to be established. Bowditch treppe, assessed with pacing stress, can be used to assess the optimal stimulation frequency and to optimise the patient's chronotropic response in programming rate-adaptive pacemakers.
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Affiliation(s)
| | - Marco Agrusta
- U.T.I.C., Clinica Montevergine, Mercogliano (AV), Italy
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Shimizu M, Nii M, Konstantinov IE, Li J, Redington AN. Isovolumic but not Ejection Phase Doppler Tissue Indices Detect Left Ventricular Dysfunction Caused by Coronary Stenosis. J Am Soc Echocardiogr 2005; 18:1241-6. [PMID: 16376749 DOI: 10.1016/j.echo.2005.03.035] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2005] [Indexed: 11/19/2022]
Abstract
BACKGROUND Isovolumic acceleration (IVA) obtained by tissue Doppler echocardiography (TDE) is a sensitive and relatively load-independent index for assessing systolic ventricular function. IVA also has the ability to describe the force-frequency relationship during incremental atrial pacing in vivo. OBJECTIVE We sought to assess the ability of IVA to detect global left ventricular (LV) dysfunction induced by coronary constriction. METHODS In 6 open-chest anesthetized pigs we examined right ventricular and LV long-axis function by TDE (4-chamber view) with simultaneous invasive measurements of intraventricular pressure, maximum dP/dt, minimum dP/dt, and tau by microtip catheter. A pneumatic cuff was placed around the proximal portion of left anterior descending coronary artery (LAD) and distal flow was monitored by transonic flow probe. Mean arterial pressures were monitored by indwelling cannula. Baseline studies assessed force-frequency relationships with TDE and invasive measurements during incremental pacing from 100 to 200/min (20/min increments every 10 minutes). The protocol was repeated 10 minutes after balloon inflation to reduce LAD blood flow by 50%. RESULTS Compared with baseline, LV pressure decreased significantly (P = .03, 2-way analysis of variance) as did maximum dP/dt (P < .004) with LAD constriction. At the same time IVA and isovolumic velocity at the LV free wall were significantly reduced (P < .002 and P = .04, respectively) and both IVA and isovolumic velocity were correlated with dP/dt (r = 0.45, P < .002, and r = 0.35, P < .02, respectively). TDE systolic indices were unchanged in the right ventricle. CONCLUSION IVA detects changes in global LV systolic function during LAD constriction and may be a useful clinical tool to diagnose ischemia.
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Affiliation(s)
- Mikiko Shimizu
- Division of Cardiology, Hospital for Sick Children, Toronto, Ontario, Canada
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25
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Ohshima S, Isobe S, Izawa H, Nanasato M, Ando A, Yamada A, Yamada K, Kato TS, Obata K, Noda A, Nishizawa T, Kato K, Nagata K, Okumura K, Murohara T, Yokota M. Cardiac sympathetic dysfunction correlates with abnormal myocardial contractile reserve in dilated cardiomyopathy patients. J Am Coll Cardiol 2005; 46:2061-8. [PMID: 16325043 DOI: 10.1016/j.jacc.2005.08.046] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/21/2005] [Revised: 06/30/2005] [Accepted: 08/01/2005] [Indexed: 11/19/2022]
Abstract
OBJECTIVES We investigated the relationship between iodine-123-metaiodobenzylguanidine (123I-MIBG) findings and myocardial contractile reserve in patients with mild to moderate dilated cardiomyopathy (DCM). BACKGROUND Little is known regarding the relationship between cardiac sympathetic nervous function and myocardial contractile reserve in DCM. METHODS Twenty-four DCM patients who showed sinus rhythm underwent echocardiography, biventricular catheterization, and myocardial 123I-MIBG scintigraphy. Left ventricular (LV) pressures were measured using a micromanometer-tipped catheter. The myocardial contractile function (LV dP/dt(max)) was determined at rest and during atrial pacing. The messenger ribonucleic acid (mRNA) expressions of intracellular Ca2+-regulatory proteins were analyzed by real-time quantitative reverse transcription-polymerase chain reaction. Myocardial 123I-MIBG accumulation was quantified as a heart-mediastinum ratio (HMR). RESULTS A significant correlation was observed between the delayed 123I-MIBG HMR and the percentage change in LV dP/dt(max) from the baseline to the peak or critical heart rate (r = 0.64; p < 0.001). The delayed 123I-MIBG HMR was significantly lower in patients showing a worsening change in LV dP/dt(max) than in those showing a favorable change (p < 0.005). The maximum LV dP/dt(max) during pacing and the sarcoplasmic reticulum Ca2+-ATPase (SERCA2) mRNA levels were significantly more reduced in patients with a delayed HMR < or =1.8 than in those with a delayed HMR >1.8 (p < 0.05, respectively). CONCLUSIONS Abnormal myocardial 123I-MIBG accumulation is related to an impaired myocardial contractile reserve and down-regulation of SERCA2 mRNA in DCM. Myocardial 123I-MIBG scintigraphy can be useful in noninvasively evaluating myocardial contractile reserve in patients with mild to moderate DCM.
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Affiliation(s)
- Satoru Ohshima
- Department of Cardiology, Nagoya University School of Medicine, Nagoya, Japan
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Bombardini T. Myocardial contractility in the echo lab: molecular, cellular and pathophysiological basis. Cardiovasc Ultrasound 2005; 3:27. [PMID: 16150150 PMCID: PMC1242240 DOI: 10.1186/1476-7120-3-27] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2005] [Accepted: 09/08/2005] [Indexed: 12/25/2022] Open
Abstract
In the standard accepted concept, contractility is the intrinsic ability of heart muscle to generate force and to shorten, independently of changes in the preload or afterload with fixed heart rates. At molecular level the crux of the contractile process lies in the changing concentrations of Ca2+ ions in the myocardial cytosol. Ca2+ ions enter through the calcium channel that opens in response to the wave of depolarization that travels along the sarcolemma. These Ca2+ ions "trigger" the release of more calcium from the sarcoplasmic reticulum (SR) and thereby initiate a contraction-relaxation cycle. In the past, several attempts were made to transfer the pure physiological concept of contractility, expressed in the isolated myocardial fiber by the maximal velocity of contraction of unloaded muscle fiber (Vmax), to the in vivo beating heart. Suga and Sagawa achieved this aim by measuring pressure/volume loops in the intact heart: during a positive inotropic intervention, the pressure volume loop reflects a smaller end-systolic volume and a higher end-systolic pressure, so that the slope of the pressure volume relationship moves upward and to the left. The pressure volume relationship is the most reliable index for assessing myocardial contractility in the intact circulation and is almost insensitive to changes in preload and after load. This is widely used in animal studies and occasionally clinically. The limit of the pressure volume relationship is that it fails to take into account the frequency-dependent regulation of contractility: the frequency-dependent control of transmembrane Ca2+ entry via voltage-gated Ca2+ channels provides cardiac cells with a highly sophisticated short-term system for the regulation of intracellular Ca2+ homeostasis. An increased stimulation rate increases the force of contraction: the explanation is repetitive Ca2+ entry with each depolarization and, hence, an accumulation of cytosolic calcium. As the heart fails, there is a change in the gene expression from the normal adult pattern to that of fetal life with an inversion of the normal positive slope of the force-frequency relation: systolic calcium release and diastolic calcium reuptake process is lowered at the basal state and, instead of accelerating for increasing heart rates, slows down. Since the force-frequency relation uncovers initial alteration of contractility, as an intermediate step between normal and abnormal contractility at rest, a practical index to measure it is mandatory. Measuring end-systolic elastance for increasing heart rates is impractical: increasing heart rates with atrial pacing has to be adjunct to the left ventricular conductance catheter, to the left ventricular pressure catheter, to the vena cava balloon, and to afterload changes. Furthermore, a noninvasive index is needed. Noninvasive measurement of the pressure/volume ratio for increasing heart rates during stress in the echo lab could be the practical answer to this new clinical demand in the current years of a dramatic increase in the number of heart failure patients.
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Affiliation(s)
- Tonino Bombardini
- Department of Echocardiography, Institute of Clinical Physiology, National Council of Research, Pisa, Italy.
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Grosu A, Bombardini T, Senni M, Duino V, Gori M, Picano E. End-systolic pressure/volume relationship during dobutamine stress echo: a prognostically useful non-invasive index of left ventricular contractility. Eur Heart J 2005; 26:2404-12. [PMID: 16105848 DOI: 10.1093/eurheartj/ehi444] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
AIMS Left ventricular end-systolic pressure-volume relationship (PVR) provides a robust, relatively load-insensitive evaluation of contractility and can be assessed non-invasively during exercise echo. Dobutamine might provide an exercise-independent alternative approach to assess inotropic reserve. The feasibility of a non-invasive estimation of PVR during dobutamine stress in the echo lab and its relationship with subsequent clinical events was assessed. METHODS AND RESULTS We enrolled 137 consecutive patients referred for dobutamine stress echo. To build the PVR, the force was determined at different heart rate increments during stepwise dobutamine infusion as the ratio of the systolic pressure/end-systolic volume index. The PVR at increasing heart rate was flat-biphasic in 65 and up-sloping in 72 patients: 42 patients underwent surgery and 95 patients were treated medically (median follow-up, 18 months; interquartile range, 12-24). Events occurred in 18 patients (death in eight, acute heart failure in 10); a flat-biphasic PVR was independent predictor of events (RR=10.16, P<0.01). CONCLUSION PVR is feasible during dobutamine stress. This index of global contractility is reasonably simple, does not affect the imaging time, and only minimally prolongs the off-line analysis time. It allows unmasking quite different, and heterogeneous, contractility reserve patterns underlying a given ejection fraction at rest. The best survival is observed in patients with up-sloping PVR, whereas flat-biphasic pattern is a strong predictor of cardiac events.
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Affiliation(s)
- Aurelia Grosu
- Department of Cardiovascular Medicine and Internal Medicine, Ospedali Riuniti, Bergamo, Italy
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Bombardini T, Agrusta M, Natsvlishvili N, Solimene F, Pap R, Coltorti F, Varga A, Mottola G, Picano E. Noninvasive assessment of left ventricular contractility by pacemaker stress echocardiography. Eur J Heart Fail 2005; 7:173-81. [PMID: 15701463 DOI: 10.1016/j.ejheart.2004.04.019] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2003] [Revised: 03/23/2004] [Accepted: 04/22/2004] [Indexed: 10/26/2022] Open
Abstract
BACKGROUND Estimating contractility of the left ventricle with noninvasive techniques is an important yet elusive goal. Positive inotropic interventions are mirrored by smaller end-systolic volumes and higher end-systolic pressures. An increased heart rate progressively increases the force of ventricular contraction (Bowditch treppe or staircase phenomenon). AIM To assess the feasibility of a noninvasive estimation of force-frequency relation (FFR) during pacing stress in the echo lab in patients with permanent pacemaker (PM). METHODS Transthoracic stress pacing echocardiography was performed in 26 patients with a permanent pacemaker (age 69+/-11 years; 21 men, 5 women). Seven patients had normal function at baseline and during stress ("normals"); eight had angiographically assessed coronary artery disease (three with and five without induced ischemia with stress echo); eleven patients had dilated cardiomyopathy (DC). To build the FFR, the force was determined at different steps as the ratio of the systolic pressure (SP, cuff sphygmomanometer)/end-systolic volume index (ESV, biplane Simpson rule/body surface area). Heart rate was determined from ECG. RESULTS The absolute value of the FFR slope was highest in controls and lowest in DC patients. A flat-downsloping FFR was found in 12/19 patients but not for normals (p<0.01). CONCLUSIONS Noninvasive pacemaker stress echocardiography (PASE) is a simple and efficient option to assess left ventricular (LV) contractility in patients with permanent pacemaker.
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Affiliation(s)
- Tonino Bombardini
- CNR, Institute of Clinical Physiology, Via Moruzzi 1, 56124 Pisa, Italy
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Bombardini T, Correia MJ, Cicerone C, Agricola E, Ripoli A, Picano E. Force-frequency relationship in the echocardiography laboratory: a noninvasive assessment of Bowditch treppe? J Am Soc Echocardiogr 2003; 16:646-55. [PMID: 12778025 DOI: 10.1016/s0894-7317(03)00221-9] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
BACKGROUND Estimation of contractility of the left ventricle is an important, and as yet elusive, goal with noninvasive techniques. OBJECTIVE We sought to assess the feasibility of a totally noninvasive estimation of force-frequency relation (FFR) during exercise stress in the echocardiography laboratory. METHODS We enrolled 13 healthy control patients (12 men, age 38 +/- 15 years) as group I, and 50 patients (38 men, age 64 +/- 11 years) referred for exercise echocardiography as group II. To build the FFR, the force was determined at each step as the ratio of the systolic pressure (cuff sphygmomanometer)/end-systolic volume index (biplane Simpson's rule/body surface area). The slope of the relationship was calculated with the linear best fit of the FFR. RESULTS Noninvasive systolic pressure/end-systolic volume ratio was obtained in all patients. The slope of the linear best fit of the force-frequency curve was lower in group II compared with group I (group II = 10.1 +/- 9.3 x 10(-2) vs group I = 14.9 +/- 9.9 x 10(-2) group I, P =.04). By regional wall-motion analysis, 2 subgroups were identified in group II: group IIA (n = 8) had a positive echocardiogram; and group IIB (n = 42) had a negative echocardiogram. The slope of the force-frequency curve was lower in patients with ischemia compared with those without (group IIA = 3.5 +/- 4.2 x 10(-2) vs group IIB = 11.4 +/- 9.5 x 10(-2); P =.012). Heart rate-systolic pressure/end-systolic volume index relation was biphasic, with an initial positive slope and a subsequent negative slope in 1 patient of group I, 4 patients of group IIA, and 15 patients of group IIB (P <.05 vs group I). CONCLUSION A noninvasive estimation of FFR can be easily determined during exercise echocardiography. This index of global contractility is theoretically appealing for identification of limited contractile reserve and latent global left ventricular dysfunction.
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Kim IS, Izawa H, Sobue T, Ishihara H, Somura F, Nishizawa T, Nagata K, Iwase M, Yokota M. Prognostic value of mechanical efficiency in ambulatory patients with idiopathic dilated cardiomyopathy in sinus rhythm. J Am Coll Cardiol 2002; 39:1264-8. [PMID: 11955842 DOI: 10.1016/s0735-1097(02)01775-8] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
OBJECTIVES The purpose of this study was to determine, by analyzing the pressure-volume relationship, the prognostic value of parameters related to myocardial energetics for predicting mortality in patients with dilated cardiomyopathy (DCM) in sinus rhythm. BACKGROUND The relationship between the myocardial energetics and the prognosis of patients with DCM in sinus rhythm remains unclear. METHODS We followed 114 ambulatory patients with nonischemic DCM in sinus rhythm for a mean period of 5.8 +/- 3.9 years. Over 70% of our patients were in New York Heart Association functional class I and class II. Pressure-volume data were obtained by the conductance method, and myocardial oxygen consumption per beat (VO(2)) measurements were obtained. RESULTS The 3-, 5-, and 10-year cumulative survival rates were 88.6%, 80.0%, and 73.9%, respectively. Of the 114 patients, 47 were selected randomly to assess their myocardial energetics. By univariate analysis, the mechanical efficiency (ME, external work/VO(2)), left ventricular (LV) ejection fraction and the LV end-diastolic pressure were statistically associated with cardiac death. The ME was the strongest predictor of survival in a Cox proportional-hazards analysis (p = 0.011). The best cutoff point of ME identified by the receiver-operating curve was 11%. This value had a sensitivity of 100%, a specificity of 87% and an overall predictive accuracy of 88% to distinguish survivors from nonsurvivors. CONCLUSIONS This study clearly demonstrates that ME is a powerful clinical predictor for cardiac death in patients with mild to moderate heart failure and with sinus rhythm. Whether these conclusions apply to patients with more severe heart failure requires further investigations.
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Affiliation(s)
- Il Sung Kim
- Cardiovascular Division, Department of Clinical Pathophysiology, Nagoya University Graduate School of Medicine, Nagoya, Japan
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31
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Takeichi Y, Yokota M, Iwase M, Izawa H, Nishizawa T, Ishiki R, Somura F, Nagata K, Isobe S, Noda A. Biphasic changes in left ventricular end-diastolic pressure during dynamic exercise in patients with nonobstructive hypertrophic cardiomyopathy. J Am Coll Cardiol 2001; 38:335-43. [PMID: 11499721 DOI: 10.1016/s0735-1097(01)01384-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
OBJECTIVES The aim of this study was to clarify the serial changes in left ventricular (LV) end-diastolic pressure (LVEDP) during dynamic exercise in patients with hypertrophic cardiomyopathy (HCM). BACKGROUND Although HCM is characterized by impaired resting LV diastolic function, serial changes in LVEDP during exercise have not been characterized. METHODS We simultaneously measured LV pressure and LV dimensions during symptom-limited supine bicycle exercise in 5 healthy individuals and 20 patients with HCM. Exercise thallium-201 scintigraphic studies were also performed. RESULTS The LVEDP (baseline: 12 +/- 5 mm Hg) progressively increased to a maximum value at peak exercise (28 +/- 8 mm Hg) in 11 patients with HCM (group I). In the remaining nine patients with HCM (group II), changes in LVEDP during exercise were biphasic, with an initial progressive increase and a subsequent gradual decline up to peak exercise (14 +/- 4 mm Hg at baseline, 27 +/- 5 mm Hg at the critical heart rate, 16 +/- 3 mm Hg at peak exercise). Exercise-induced changes in LV dimensions and LV peak systolic pressures were similar in both groups. However, the maximum first derivative of LV pressure was greater and the LV pressure half-time was shorter in group II than in group I at a similar peak exercise heart rate. The biphasic changes in LVEDP disappeared by pretreatment with propranolol. The LV hypertrophy scores were higher in group I than in group II. Exercise thallium-201 images showed more severe perfusion defects in group I than in group II patients. CONCLUSIONS The biphasic changes in LVEDP seen during exercise may be related to improved coronary microcirculation in response to beta-adrenergic stimulation in patients with mild to moderate HCM.
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Affiliation(s)
- Y Takeichi
- Cardiovascular Division, Nagoya University, Graduate School of Medicine, Japan
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Zuo P, Izawa H, Ishiki R, Noda A, Nishizawa T, Shigemura K, Nagata K, Iwase M, Yokota M. Different beta-adrenergic regulation of myocardial contraction and relaxation between apical and nonobstructive hypertrophic cardiomyopathy. Am Heart J 2000; 140:329-37. [PMID: 10925351 DOI: 10.1067/mhj.2000.107999] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
BACKGROUND The impaired adrenergic control of both inotropic and lusitropic reserves has been evaluated in patients with hypertrophic cardiomyopathy (HCM) but not in those with apical HCM (APH). OBJECTIVES We examined the influence of increases in heart rate and adrenergic stimulation on inotropic and lusitropic reserves in HCM and APH with normal resting left ventricular (LV) systolic function. METHODS We evaluated LV isovolumic contraction and relaxation during atrial pacing and during supine leg exercise in 7 patients with APH and in 8 patients with HCM. RESULTS Heart rate was significantly correlated with LV isovolumic contraction and relaxation during pacing and exercise in all patients. In all patients with APH, the increase in LV isovolumic contraction was greater during exercise (101%) than pacing alone (27%) for similar increase in heart rate. In 5 patients with HCM, the increase in LV isovolumic contraction was greater during exercise (83%) than pacing alone (24%), whereas in 3 patients with HCM the increase in LV isovolumic contraction was similar between during exercise (25%) and during pacing alone (22%). In all patients with APH, relaxation was shorter during exercise (39%) than pacing alone (16%). Conversely, in patients with HCM relaxation was similarly shortened between during pacing alone (20%) and during exercise (19%). CONCLUSIONS The force-frequency and the relaxation-frequency relations were well-preserved in all patients. In patients with HCM, the adrenergic enhancement of force-frequency relation and/or relaxation-frequency relation was impaired. In patients with APH, however, adrenergic control of both force-frequency and relaxation-frequency relations was well-preserved, which may indicate a preserved beta-adrenergic signaling pathway.
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Affiliation(s)
- P Zuo
- Department of Clinical Laboratory Medicine, and the First Department of Internal Medicine, Nagoya University School of Medicine, Japan
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Shinke T, Takeuchi M, Takaoka H, Yokoyama M. Beneficial effects of heart rate reduction on cardiac mechanics and energetics in patients with left ventricular dysfunction. JAPANESE CIRCULATION JOURNAL 1999; 63:957-64. [PMID: 10614841 DOI: 10.1253/jcj.63.957] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
It has been shown recently that the force-frequency relationship is blunted in experimental heart failure models. Furthermore, tachycardia is thought to have adverse effects on the diseased heart for several reasons, one of which is an increase in myocardial oxygen consumption. Inversely, the oxygen-saving effects of bradycardia may be beneficial for the treatment of heart failure. The aim of this study was to elucidate how heart rate (HR) modulates cardiac mechanics and energetics in patients with left ventricular (LV) dysfunction. LV pressure-volume data and myocardial oxygen consumption (MVO2) was assessed using conductance and coronary sinus thermodilution catheters in 14 patients with moderate LV dysfunction (mean ejection fraction 34%) under 3 conditions: (a) basal, (b) HR increased by 20% using atrial pacing, and (c) HR decreased by 16% using a specific bradycardic agent, zatebradine (7.5 mg p.o.). Atrial pacing decreased external work (EW) (from 0.39 to 0.31 J beat(-1) m(-2), p<0.05) at a comparable MVO2 per beat with a marginal increase in LV contractility index (Ees) (from 2.34 to 2.76 mm Hg ml(-1) m(-2), p = 0.08), resulting in a decrease in mechanical efficiency (EW/MVO2) (from 25.9 to 22.1%, p<0.05). In contrast, zatebradine did not decrease Ees (from 2.34 to 2.24 mm Hg ml(-1) m(-2), NS), but increased EW (from 0.39 to 0.42 J beat(-1) m(-2), p<0.05 vs. basal level) without a change in MVO2 per beat, resulting in improved mechanical efficiency (from 25.9 to 29.7%, p<0.05 vs. basal level). These results suggest that mild bradycardia is energetically advantageous and does not decrease myocardial contractility and performance, whereas pacing-induced tachycardia worsens cardiac mechanics and energetics in patients with LV dysfunction. Thus, the oxygen-saving effect of bradycardia may be beneficial for the treatment of heart failure.
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Affiliation(s)
- T Shinke
- The First Department of Internal Medicine Kobe University School of Medicine, Japan
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