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Bamaiyi AJ, Norton GR, Peterson V, Norman G, Mojiminiyi FB, Woodiwiss AJ. Limited Impact of β-Adrenergic Receptor Activation on Left Ventricular Diastolic Function in Rat Models of Hypertensive Heart Disease. J Cardiovasc Pharmacol 2018; 72:242-251. [PMID: 30403389 DOI: 10.1097/fjc.0000000000000620] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Hypertension is a major cause of left ventricular (LV) diastolic dysfunction. Although β-adrenergic receptor (β-AR) blockers are often used to manage hypertension, the impact of β-AR activation on LV lusitropic effects and hence filling pressures in the hypertensive heart with LV diastolic dysfunction is uncertain. METHODS Using tissue Doppler imaging and Speckle tracking software, we assessed LV function in isoflurane anesthetised spontaneously hypertensive (SHR) and Dahl salt-sensitive (DSS) rats before and after β-AR activation [isoproterenol (ISO) administration]. RESULTS As compared to normotensive Wistar Kyoto control rats, or DSS rats not receiving NaCl in the drinking water, SHR and DSS rats receiving NaCl in the drinking water had a reduced myocardial relaxation as indexed by lateral wall e' (early diastolic tissue velocity at the level of the mitral annulus) and an increased LV filling pressure as indexed by E/e'. However, LV ejection fraction and deformation and motion were preserved in both SHR and DSS rats. The administration of ISO resulted in a marked increase in ejection fraction and decrease in LV filling volumes in all groups, and an increase in e' in SHR, but not DSS rats. However, after ISO administration, although E/e' decreased in DSS rats in association with a reduced filling volume, E/e' in SHR remained unchanged and SHR retained greater values than Wistar Kyoto control. CONCLUSIONS The hypertensive heart is characterized by reductions in myocardial relaxation and increases in filling pressures, but β-AR activation may fail to improve myocardial relaxation and when this occurs, it does not reduce LV filling pressures.
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Affiliation(s)
- Adamu J Bamaiyi
- Cardiovascular Pathophysiology and Genomics Research Unit, School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Gavin R Norton
- Cardiovascular Pathophysiology and Genomics Research Unit, School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Vernice Peterson
- Cardiovascular Pathophysiology and Genomics Research Unit, School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Glenda Norman
- Cardiovascular Pathophysiology and Genomics Research Unit, School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Frank B Mojiminiyi
- Department of Physiology, Faculty of Basic Medical Sciences, College of Health Sciences, Usmanu Danfodiyo University, Sokoto, Nigeria
| | - Angela J Woodiwiss
- Cardiovascular Pathophysiology and Genomics Research Unit, School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
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Kano N, Okumura T, Isobe S, Sawamura A, Watanabe N, Fukaya K, Mori H, Morimoto R, Kato K, Bando YK, Murohara T. Left ventricular phase entropy: Novel prognostic predictor in patients with dilated cardiomyopathy and narrow QRS. J Nucl Cardiol 2018; 25:1677-1687. [PMID: 28176257 DOI: 10.1007/s12350-017-0807-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Accepted: 01/17/2017] [Indexed: 10/20/2022]
Abstract
BACKGROUND The prognostic impact and pathophysiology of global left ventricular mechanical dyssynchrony (LVMD), namely mechanical dyssynchrony of whole left ventricle, as assessed by phase analysis of electrocardiographically gated (ECG-gated) myocardial perfusion SPECT has not been clearly elucidated in patients with dilated cardiomyopathy (DCM) and narrow QRS complex (<120 ms). METHODS AND RESULTS Forty-six patients with DCM underwent ECG-gated myocardial 99mTc-sestamibi perfusion SPECT and endomyocardial biopsy. LV phase entropy was automatically calculated using a phase analysis of ECG-gated myocardial perfusion SPECT. The patients were divided into two groups according to the median phase entropy value: low-phase entropy (<0.61) (N = 23: LE group) and high-phase entropy (≥0.61) (N = 23: HE group). In the Kaplan-Meier survival analysis, the event-free survival rate was significantly lower in the HE group (log-rank P = 0.015). Moreover, high-phase entropy was an independent predictor of adverse cardiac events (hazard ratio, 5.77%; 95% confidence interval, 1.02-108.32; P = 0.047). Interestingly, the mRNA expression levels of sarcoplasmic reticulum Ca2+-ATPase (SERCA2a) in endomyocardial biopsy specimens were significantly lower in the HE group (P = 0.015). CONCLUSION LV phase entropy, which may reflect impairment of Ca2+ handling caused by decreased SERCA2a mRNA levels, is a novel prognostic predictor in patients with DCM and narrow QRS complex.
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Affiliation(s)
- Naoaki Kano
- Department of Cardiology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, Aichi, 466-8550, Japan
| | - Takahiro Okumura
- Department of Cardiology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, Aichi, 466-8550, Japan.
| | - Satoshi Isobe
- Department of Cardiology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, Aichi, 466-8550, Japan
| | - Akinori Sawamura
- Department of Cardiology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, Aichi, 466-8550, Japan
| | - Naoki Watanabe
- Department of Cardiology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, Aichi, 466-8550, Japan
| | - Kenji Fukaya
- Department of Cardiology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, Aichi, 466-8550, Japan
| | - Hiroaki Mori
- Department of Cardiology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, Aichi, 466-8550, Japan
| | - Ryota Morimoto
- Department of Cardiology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, Aichi, 466-8550, Japan
- Department of CKD Initiatives Internal Medicine, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Katsuhiko Kato
- Department of Radiological and Medical Laboratory Sciences, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Yasuko K Bando
- Department of Cardiology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, Aichi, 466-8550, Japan
| | - Toyoaki Murohara
- Department of Cardiology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, Aichi, 466-8550, Japan
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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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Esfandiari S, Fuchs F, Wainstein RV, Chelvanathan A, Mitoff P, Sasson Z, Mak S. Heart rate-dependent left ventricular diastolic function in patients with and without heart failure. J Card Fail 2014; 21:68-75. [PMID: 25451706 DOI: 10.1016/j.cardfail.2014.10.013] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Revised: 10/09/2014] [Accepted: 10/20/2014] [Indexed: 11/25/2022]
Abstract
BACKGROUND Chronic heart rate (HR) reduction in the treatment of heart failure (HF) with systolic dysfunction is beneficial, but the immediate mechanical advantages or disadvantages of altering HR are incompletely understood. We examined the effects of increasing HR on early and late diastole in humans with and without HF. METHODS AND RESULTS We studied force-interval relationships of the left ventricle (LV) in 11 HF patients and 14 control subjects. HR was controlled by right atrial pacing, and LV pressure was recorded by a micromanometer-tipped catheter. The time constant of isovolumic relaxation (tau) was calculated, and simultaneous sonographic images were analyzed for LV volumes. The end-diastolic pressure-volume relationship (EDPVR) was analyzed with the use of a single-beat method. Tau was shortened in response to increasing HR in both groups; the slope of this relationship was steeper in HF than in control subjects. The predicted volume at a theoretic pressure of 0 mm Hg (V30) increased at higher HRs compared with baseline, shifting the predicted EDPVR compliance curve to the right in HF patients but not in control subjects. CONCLUSIONS In HF, changes in HR affect early relaxation and diastolic compliance to a greater extent than in control subjects. Our study reinforces current recommendations for HR-lowering drug treatment in HF.
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Affiliation(s)
- Sam Esfandiari
- Division of Cardiology, Mount Sinai Hospital, University of Toronto, Toronto, Ontario, Canada; Institute of Medical Science, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Felipe Fuchs
- Division of Cardiology, Mount Sinai Hospital/University Health Network, Toronto, Ontario, Canada
| | - Rodrigo V Wainstein
- Division of Cardiology, Hospital de Clinicas de Porto Alegre, Porto Alegre, Brazil
| | - Anjala Chelvanathan
- Division of Cardiology, Mount Sinai Hospital, University of Toronto, Toronto, Ontario, Canada
| | - Peter Mitoff
- Division of Cardiology, Mount Sinai Hospital, University of Toronto, Toronto, Ontario, Canada
| | - Zion Sasson
- Division of Cardiology, Mount Sinai Hospital, University of Toronto, Toronto, Ontario, Canada
| | - Susanna Mak
- Division of Cardiology, Mount Sinai Hospital, University of Toronto, Toronto, Ontario, Canada.
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Noninvasive evaluation of left ventricular force-frequency relationships by measuring carotid arterial wave intensity during exercise stress. J Med Ultrason (2001) 2014; 42:65-70. [PMID: 25620873 PMCID: PMC4300423 DOI: 10.1007/s10396-014-0554-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2014] [Accepted: 05/14/2014] [Indexed: 11/08/2022]
Abstract
Background and purpose Estimation of the contractility of the left ventricle during exercise is important in drawing up a protocol of cardiac rehabilitation. It has been demonstrated that color Doppler- and echo tracking-derived carotid arterial wave intensity is a sensitive index of global left ventricular (LV) contractility. We assessed the feasibility of measuring carotid arterial wave intensity and determining force−frequency (contractility−heart rate) relations (FFRs) during exercise totally noninvasively. Methods We measured carotid arterial wave intensity with a combined color Doppler and echo tracking system in 25 healthy young male volunteers (age 20.8 ± 1.2 years) at rest and during exercise. FFRs were constructed by plotting the maximum value of wave intensity (WD1) against heart rate (HR). Results We first confirmed that HR increased linearly with an increase in work load in each subject (r2 = 0.95 ± 0.04). WD1 increased linearly with an increase in HR. The goodness-of-fit of the regression line of WD1 on HR in each subject was very high (r2 = 0.48−0.94, p < 0.0001, respectively). The slope of the WD1-HR relation ranged 0.30−2.20 [m/s3 (beat/min)]. Conclusions Global LV FFRs can be generated in healthy young volunteers with an entirely noninvasive combination of exercise and wave intensity. These data should show the potential usefulness of the FFR in the context of cardiac rehabilitation.
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Yamada T, Hirashiki A, Cheng XW, Okumura T, Shimazu S, Okamoto R, Shinoda N, Isobe S, Takeshita K, Naganawa S, Kondo T, Murohara T. Relationship of myocardial fibrosis to left ventricular and mitochondrial function in nonischemic dilated cardiomyopathy--a comparison of focal and interstitial fibrosis. J Card Fail 2014; 19:557-64. [PMID: 23910585 DOI: 10.1016/j.cardfail.2013.05.018] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2013] [Revised: 04/14/2013] [Accepted: 05/31/2013] [Indexed: 12/29/2022]
Abstract
BACKGROUND Mitochondrial damage is associated with histologic myocardial fibrosis. Late gadolinium enhancement (LGE) on cardiac magnetic resonance (CMR) can be used to identify focal fibrosis. We examined whether myocardial fibrosis on CMR and collagen volume fraction (CVF) from biopsies correlated with left ventricular (LV) and mitochondrial function in patients with nonischemic dilated cardiomyopathy (DCM). METHODS AND RESULTS Fifty-nine DCM patients underwent CMR, cardiac catheterization, and endomyocardial biopsy. Minimum first derivative of LV pressure (LVdP/dt(min)) was measured as an index of LV relaxation. Mitochondrial RNA expression was also analyzed. For quantitative analysis of myocardial fibrosis, percentage LGE (%LGE) and CVF were calculated. Patients were divided into 2 groups on the basis of the presence (LGE group; n = 27) or absence (non-LGE group; n = 32) of LGE. Mean CVF and absolute value of LVdP/dt(min) were significantly higher and lower, respectively, in the LGE group than in the non-LGE group. Multivariate analysis revealed that %LGE was an independent determinant of LVdP/dt(min). The abundance of mitochondrial enzyme mRNA was significantly lower in the LGE group. CONCLUSIONS Noninvasive CMR imaging is more useful in predicting diastolic dysfunction than invasive histologic assessments. In addition, it might indicate mitochondrial dysfunction in DCM.
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Affiliation(s)
- Takashi Yamada
- Department of Cardiology, Nagoya University Graduate School of Medicine, Nagoya, Japan
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Masutani S, Cheng HJ, Morimoto A, Hasegawa H, Han QH, Little WC, Cheng CP. β3-Adrenergic receptor antagonist improves exercise performance in pacing-induced heart failure. Am J Physiol Heart Circ Physiol 2013; 305:H923-30. [PMID: 23873794 PMCID: PMC3761346 DOI: 10.1152/ajpheart.00371.2012] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2012] [Accepted: 07/13/2013] [Indexed: 11/22/2022]
Abstract
In heart failure (HF), the impaired left ventricular (LV) arterial coupling and diastolic dysfunction present at rest are exacerbated during exercise. We have previously shown that in HF at rest stimulation of β3-adrenergic receptors by endogenous catecholamine depresses LV contraction and relaxation. β3-Adrenergic receptors are activated at higher concentrations of catecholamine. Thus exercise may cause increased stimulation of cardiac β3-adrenergic receptors and contribute to this abnormal response. We assessed the effect of L-748,337 (50 μg/kg iv), a selective β3-adrenergic receptor antagonist (β3-ANT), on LV dynamics during exercise in 12 chronically instrumented dogs with pacing-induced HF. Compared with HF at rest, exercise increased LV end-systolic pressure (PES), minimum LV pressure (LVPmin), and the time constant of LV relaxation (τ) with an upward shift of early diastolic portion of LV pressure-volume loop. LV contractility decreased and arterial elastance (EA) increased. LV arterial coupling (EES/EA) (0.40 vs. 0.51) was impaired. Compared with exercise in HF preparation, exercise after β3-ANT caused similar increases in heart rate and PES but significantly decreased τ (34.9 vs. 38.3 ms) and LVPmin with a downward shift of the early diastolic portion of LV pressure-volume loop and further augmented dV/dtmax. Both EES and EES/EA (0.68 vs. 0.40) were increased. LV mechanical efficiency improved from 0.39 to 0.53. In conclusion, after HF, β3-ANT improves LV diastolic filling; increases LV contractility, LV arterial coupling, and mechanical efficiency; and improves exercise performance.
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Affiliation(s)
- Satoshi Masutani
- Cardiology Section, Wake Forest School of Medicine, Winston-Salem, North Carolina
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Tanaka H, Matsuda T, Tobina T, Yamada Y, Yamagishi T, Sakai H, Obara S, Higaki Y, Kiyonaga A, Brubaker PH. Product of Heart Rate and First Heart Sound Amplitude as an Index of Myocardial Metabolic Stress During Graded Exercise. Circ J 2013; 77:2736-41. [DOI: 10.1253/circj.cj-12-1610] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Hiroaki Tanaka
- Fukuoka University Institute for Physical Activity, Faculty of Sports and Health Science, Fukuoka University
| | - Takuro Matsuda
- Fukuoka University Institute for Physical Activity, Faculty of Sports and Health Science, Fukuoka University
| | - Takuro Tobina
- Fukuoka University Institute for Physical Activity, Faculty of Sports and Health Science, Fukuoka University
| | - Yousuke Yamada
- Fukuoka University Institute for Physical Activity, Faculty of Sports and Health Science, Fukuoka University
| | | | | | - Shigeru Obara
- Faculty of Integrated Arts and Sciences, University of Tokushima
| | - Yasuki Higaki
- Fukuoka University Institute for Physical Activity, Faculty of Sports and Health Science, Fukuoka University
| | - Akira Kiyonaga
- Fukuoka University Institute for Physical Activity, Faculty of Sports and Health Science, Fukuoka University
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Tanaka M, Sugawara M, Ogasawara Y, Suminoe I, Izumi T, Hiramatsu O, Kajiya F. Noninvasive assessment of left ventricular force-frequency relationships by measuring carotid arterial wave intensity during exercise stress. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2013; 2013:687-690. [PMID: 24109780 DOI: 10.1109/embc.2013.6609593] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
BACKGROUND Evaluation of the contractile state of the left ventricle during exercise is important in drawing up a protocol of cardiac rehabilitation. It has been demonstrated that color Doppler- and echo tracking-derived carotid arterial wave intensity is a sensitive index of global left ventricular (LV) contractility. OBJECTIVES We assessed the feasibility of measuring carotid arterial wave intensity and determining force-frequency (contractility-heart rate) relationships (FFR's) during exercise totally noninvasively. METHODS We measured carotid arterial wave intensity with a combined color Doppler and echo tracking system in 15 healthy young male volunteers (age 20.8 ± 1.3 years) at rest and during exercise. FFR's were constructed by plotting the maximum value of wave intensity (WD1) against heart rate (HR). RESULTS WD1 increased linearly with an increase in HR. The goodness-of-fit of the regression line of WD1 on HR in each subject was very high (r2 0.67 ~ 0.91, p < 0.0001 respectively). The slope of the WD1-HR relation ranged from 0.31 to 1.52 [m/s(3)(beat/min)]. CONCLUSIONS A global LV FFR can be generated in healthy young volunteers with an entirely noninvasive combination of exercise and wave intensity. These data should show the potential usefulness of FFR in the context of cardiac rehabilitation.
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Ohara T, Niebel CL, Stewart KC, Charonko JJ, Pu M, Vlachos PP, Little WC. Loss of Adrenergic Augmentation of Diastolic Intra-LV Pressure Difference in Patients With Diastolic Dysfunction. JACC Cardiovasc Imaging 2012; 5:861-70. [DOI: 10.1016/j.jcmg.2012.05.013] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2012] [Revised: 05/08/2012] [Accepted: 05/21/2012] [Indexed: 10/27/2022]
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Qintar M, Morad A, Alhawasli H, Shorbaji K, Firwana B, Essali A, Kadro W. Pacing for drug-refractory or drug-intolerant hypertrophic cardiomyopathy. Cochrane Database Syst Rev 2012; 2012:CD008523. [PMID: 22592731 PMCID: PMC8094451 DOI: 10.1002/14651858.cd008523.pub2] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
BACKGROUND Hypertrophic cardiomyopathy (HCM) is a genetic disease with an autosomal-dominant inheritance for which negative inotropes are the most widely used initial therapies. Observational studies and small randomised trials have suggested symptomatic and functional benefits using pacing and several theories have been put forward to explain why. Pacing, although not the primary treatment for HCM, could be beneficial to patients with relative or absolute contraindications to surgery or alcohol ablation. Several randomised controlled trials comparing pacing to other therapeutic modalities have been conducted but no Cochrane-style systematic review has been done. OBJECTIVES To assess the effects of pacing in drug-refractory or drug-intolerant hypertrophic cardiomyopathy patients. SEARCH METHODS We searched the following on the 14/4/2010: CENTRAL (The Cochrane Library 2010, Issue 1), MEDLINE OVID (from 1950 onwards ), EMBASE OVID (from 1980 onwards ), Web of Science with Conference Proceedings (from 1970 onwards). No language restrictions were applied. SELECTION CRITERIA Randomised controlled trials of either parallel or crossover design that assess the beneficial and harmful effects of pacing for hypertrophic cardiomyopathy were included. When crossover studies were identified, we considered data only from the first phase. DATA COLLECTION AND ANALYSIS Data from included studies were extracted onto a pre-formed data extraction paper by two authors independently. Data was then entered into Review Manager 5.1 for analysis. Risk of bias was assessed using the guidance provided in the Cochrane Handbook. For dichotomous data, relative risk was calculated; and for continuous data, the mean differences were calculated. Where appropriate data were available, meta-analysis was performed. Where meta-analysis was not possible, a narrative synthesis was written. A QUROUM flow chart was provided to show the flow of papers. MAIN RESULTS Five studies (reported in 10 papers) were identified. However, three of the five studies provided un-usable data. Thus the data from only two studies (reported in seven papers) with 105 participants were included for this review. There was insufficient data to compare results on all-cause mortality, cost effectiveness, exercise capacity, Quality of life and Peak O2 consumption.When comparing active pacing versus placebo pacing on exercise capacity, one study showed that exercise time decreased from (13.1 ± 4.4) minutes to (12.6 ± 4.3) minutes in the placebo group and increased from (12.1 ± 5.6) minutes to (12.9 ± 4.2) minutes in the treatment group (MD 0.30; 95% CI -1.54 to 2.14). Statistically significant data from the same study showed that left ventricular outflow tract obstruction decreased from (71 ± 32) mm Hg to (52 ± 34) mm Hg in the placebo group and from (70 ± 24) mm Hg to (33 ± 27) mm Hg in the active pacing group (MD -19.00; 95% CI -32.29 to -5.71). This study was also able to show that New York Heart Association (NYHA) functional class decreased from (2.5 ± 0.5) to (2.2 ± 0.6) in the inactive pacing group and decreased from (2.6 ± 0.5) to (1.7 ± 0.7) in the placebo group (MD -0.50; 95% CI -0.78 to -0.22).When comparing active pacing versus trancoronary ablation of septal hypertrophy (TASH), data from one study showed that NYHA functional class decreased from (3.2 ± 0.7) to (1.5 ± 0.5) in the TASH group and decreased from (3.0 ± 0.1) to (1.9 ± 0.6) in the pacemaker group. This study also showed that LV wall thickness remained unchanged in the active pacing group compared to reduction from (22 ± 4) mm to (17 ± 3) mm in the TASH group (MD 0.60; 95% CI -5.65 to 6.85) and that LV outflow tract obstruction decreased from (80 ± 35.5) mm Hg in the TASH group to (49.3 ± 37.7) mm Hg in the pacemaker group. AUTHORS' CONCLUSIONS Trials published to date lack information on clinically relevant end-points. Existing data is derived from small trials at high risk of bias, which concentrate on physiological measures. Their results are inconclusive. Further large and high quality trials with more appropriate outcomes are warranted.
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Affiliation(s)
- Mohammed Qintar
- Cleveland Clinic, OH, USA, Faculty of Medicine, Damascus University, Damascus, Syrian Arab Republic.
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Masutani S, Cheng HJ, Tachibana H, Little WC, Cheng CP. Levosimendan restores the positive force-frequency relation in heart failure. Am J Physiol Heart Circ Physiol 2011; 301:H488-96. [PMID: 21572004 PMCID: PMC3154658 DOI: 10.1152/ajpheart.01116.2010] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/05/2010] [Accepted: 05/10/2011] [Indexed: 11/22/2022]
Abstract
Frequency potentiation of contractile function is a major mechanism of the increase in myocardial performance during exercise. In heart failure (HF), this positive force-frequency relation is impaired, and the abnormal left ventricular (LV)-arterial coupling is exacerbated by tachycardia. A myofilament Ca(2+) sensitizer, levosimendan, has been shown to improve exercise tolerance in HF. This may be due to its beneficial actions on the force-frequency relation and LV-arterial coupling (end-systolic elastance/arterial elastance, E(ES)/E(A)). We assessed the effects of therapeutic doses of levosimendan on the force-frequency relation and E(ES)/E(A) in nine conscious dogs after pacing-induced HF using pressure-volume analysis. Before HF, pacing tachycardia increased E(ES), shortened τ, and did not impair E(ES)/E(A) and mechanical efficiency (stroke work/pressure-volume area, SW/PVA). In contrast, after HF, pacing at 140, 160, 180, and 200 beat/min (bpm) produced smaller a increase of E(ES) or less shortening of τ, whereas E(ES)/E(A) (from 0.56 at baseline to 0.42 at 200 bpm) and SW/PVA (from 0.52 at baseline to 0.43 at 200 bpm) progressively decreased. With levosimendan, basal E(ES) increased 27% (6.2 mmHg/ml), τ decreased 11% (40.8 ms), E(ES)/E(A) increased 34% (0.75), and SW/PVA improved by 15% (0.60). During tachycardia, E(ES) further increased by 23%, 37%, 68%, and 89%; τ decreased by 9%, 12%, 15%, and 17%; and E(ES)/E(A) was augmented by 11%, 16%, 31%, and 33%, incrementally, with pacing rate. SW/PVA was improved (0.61 to 0.64). In conclusion, in HF, treatment with levosimendan restores the normal positive LV systolic and diastolic force-frequency relation and prevents tachycardia-induced adverse effect on LV-arterial coupling and mechanical efficiency.
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Affiliation(s)
- Satoshi Masutani
- Cardiology Section, Wake Forest University School of Medicine, Winston-Salem, North Carolina, USA
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Isobe S, Ohshima S, Unno K, Izawa H, Kato K, Noda A, Hirashiki A, Murohara T. Relation of 99mTc-sestamibi washout with myocardial properties in patients with hypertrophic cardiomyopathy. J Nucl Cardiol 2010; 17:1082-90. [PMID: 20635229 DOI: 10.1007/s12350-010-9266-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2010] [Accepted: 06/14/2010] [Indexed: 11/24/2022]
Abstract
BACKGROUND We sought to determine the relationship between (99m)Tc-sestamibi washout and myocardial properties in hypertrophic cardiomyopathy (HCM) patients. METHODS AND RESULTS Twenty-four HCM patients underwent biventricular cardiac catheterization, with a micromanometer-tipped catheter, both at rest and during atrial pacing, echocardiography and myocardial (99m)Tc-sestamibi scintigraphy at rest. The (99m)Tc-sestamibi washout rate (WR) was calculated using initial and delayed planar images. The HCM patients were divided into two groups as follows: Group A consisted of 13 patients showing (99m)Tc-sestamibi WR < 22.5%; group B of 11 patients showing (99m)Tc-sestamibi WR ≥ 22.5%. Significant correlations were observed between (99m)Tc-sestamibi WR and percentage changes in pressure half-time (T (1/2)), as well as those in the maximum first derivative LV pressure (LV dP/dt (max)) (r = .43, P = .033; r = -.63, P = .001). The percentage changes in LV dP/dt (max) and those in T (1/2) were significantly more reduced in group B than in group A (P < .05). The biphasic force-frequency relation was more frequently observed in group B than in group A (82% vs. 18%). CONCLUSION Increased (99m)Tc-sestamibi washout is associated with an impaired contractile reserve and prolonged relaxation, suggesting that myocardial (99m)Tc-sestamibi scintigraphy may be useful in noninvasively detecting the early impairment of myocardial function in HCM patients.
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Affiliation(s)
- Satoshi Isobe
- Department of Cardiology, Kami-iida Dai-ichi General Hospital, Kita-ku, Nagoya, Japan.
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14
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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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15
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Kurita T, Onishi K, Dohi K, Tanabe M, Fujimoto N, Tanigawa T, Setsuda M, Isaka N, Nobori T, Ito M. Impact of heart rate on mechanical dyssynchrony and left ventricular contractility in patients with heart failure and normal QRS duration. Eur J Heart Fail 2007; 9:637-43. [PMID: 17467334 DOI: 10.1016/j.ejheart.2007.03.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2006] [Revised: 01/11/2007] [Accepted: 03/06/2007] [Indexed: 11/23/2022] Open
Abstract
AIMS The quantification of mechanical dyssynchrony has important diagnostic value and may help to determine optimal therapy in heart failure (HF). We hypothesized that mechanical dyssynchrony may be augmented at increased heart rates in patients with HF and normal QRS duration. METHODS AND RESULTS From online segmental conductance catheter signals, we derived indices to quantify temporal and spatial aspects of mechanical dyssynchrony during systole in 20 control subjects, 20 HF patients with normal QRS duration, and 12 HF patients with complete left bundle branch block (CLBBB). Data were collected at baseline, and then following a 40 bpm increase in heart rate induced by right atrial pacing. Mechanical dyssynchrony in HF patients with normal QRS duration or CLBBB was higher than that found in control subjects. In HF patients with normal QRS duration, mechanical dyssynchrony increased from 37.4+/-4.8% at baseline to 43.2+/-4.4% with increased heart rate (p<0.01), the resultant degree of mechanical dyssynchrony was similar to that at baseline in the HF patients with CLBBB. Increased heart rate did not affect dyssynchrony in the control patients. CONCLUSION Mechanical dyssynchrony was augmented as heart rate increased by right atrial pacing in patients with HF and normal QRS duration.
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Affiliation(s)
- Tairo Kurita
- Department of Cardiology, Mie University Graduate School of Medicine, 2-174 Edobashi, Tsu 514-8507, Japan
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16
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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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17
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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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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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19
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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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20
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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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21
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Kato T, Noda A, Izawa H, Nishizawa T, Somura F, Yamada A, Nagata K, Iwase M, Nakao A, Yokota M. Myocardial velocity gradient as a noninvasively determined index of left ventricular diastolic dysfunction in patients with hypertrophic cardiomyopathy. J Am Coll Cardiol 2003; 42:278-85. [PMID: 12875764 DOI: 10.1016/s0735-1097(03)00573-4] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
OBJECTIVES We investigated the utility of the peak negative myocardial velocity gradient (MVG) derived from tissue Doppler imaging (TDI) for evaluation of diastolic dysfunction in patients with hypertrophic cardiomyopathy (HCM). BACKGROUND Hypertrophic cardiomyopathy is characterized by impaired diastolic function with abnormal stiffness and prolonged relaxation. However, it remains difficult to evaluate these defects noninvasively. METHODS Both TDI and conventional echocardiography were performed in 36 patients with HCM and in 47 control subjects. Left ventricular (LV) pressure was measured simultaneously in all HCM patients and in 26 controls. RESULTS The peak negative MVG occurred soon after the isovolumic relaxation period during the initial phase of rapid filling (auxotonic relaxation). It was significantly smaller in HCM patients than in control subjects (2.32 +/- 0.52/s vs. 4.82 +/- 1.15/s, p < 0.0001); the cutoff value for differentiation between all HCM patients and 47 normal individuals was determined as 3.2/s. Both the left ventricular end-diastolic pressure (LVEDP) (19.6 +/- 6.1 mm Hg vs. 6.5 +/- 1.7 mm Hg, p < 0.0001) and the time constant of LV pressure decay during isovolumic diastole (tau) (44.0 +/- 6.7 ms vs. 32.1 +/- 5.5 ms, p < 0.0001) were increased in HCM patients compared with controls. The peak negative MVG was negatively correlated with both LVEDP (r = -0.75, p < 0.0001) and tau (r = -0.58, p < 0.0001). CONCLUSIONS A reduced peak negative MVG reflects both prolonged relaxation and elevated LVEDP. The peak negative MVG might thus provide a noninvasive index of diastolic function, yielding unique information about auxotonic relaxation in patients with HCM.
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Affiliation(s)
- Tomoko Kato
- Cardiovascular Division, Department of Clinical Pathophysiology, Nagoya University, Graduate School of Medicine, Nagoya, Japan
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22
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Umeda H, Iwase M, Izawa H, Nishizawa T, Nonokawa M, Isobe S, Noda A, Nagata K, Ishihara H, Yokota M. Biphasic relaxation-frequency relations in patients with effort angina pectoris: a new marker of myocardial demand ischemia. Am Heart J 2003; 146:75-83. [PMID: 12851611 DOI: 10.1016/s0002-8703(03)00149-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
BACKGROUND Relaxation-frequency relations (RFR) during demand ischemia have not been fully examined in patients with effort angina pectoris (AP). We sought to clarify the effects of pacing and exercise on RFR in patients with AP. METHODS We recorded left ventricular (LV) pressures during rapid atrial pacing and symptom-limited supine bicycle exercise. RFR were analyzed in 24 patients with AP and 10 controls. RESULTS LV pressure half-time (T(1/2)) in controls was gradually shortened with an increase in heart rate (HR) during pacing (-19% +/- 6% at peak HR). The changes in T(1/2) during pacing were biphasic with initial shortening (-12% +/- 5% at the critical HR) followed by prolongation (-3% +/- 7% at peak HR) in all patients with AP. The critical HR, at which T(1/2) was minimum, preceded the HR at 0.1-mV ST-segment depression, and finally chest pain occurred. The critical HR was correlated negatively with the severity of ischemia as assessed by thallium-201 scintigraphy. T(1/2) was remarkably shortened during exercise in controls (-41% +/- 10% at peak exercise). In patients with AP, 2 distinct patterns of RFR were observed during exercise. T(1/2) was shortened progressively (-37% +/- 8% at peak exercise) in 15 patients, whereas RFR remained biphasic (-21% +/- 10% at the critical HR and -11% +/- 11% at peak exercise) in the other 9 patients. Coronary angiography and exercise scintigraphy suggested more severe ischemia in patients with biphasic RFR during exercise. CONCLUSIONS Impaired RFR might be the most sensitive parameter of pacing-induced ischemia. The critical HR was closely related with severity of ischemia. Adverse effects of ischemia on LV relaxation may be alleviated by exercise.
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Affiliation(s)
- Hisashi Umeda
- Department of Organ Regulation and Internal Medicine, Nagoya University, Graduate School of Medicine, Nagoya, Japan
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23
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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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24
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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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25
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Freeman K, Colon-Rivera C, Olsson MC, Moore RL, Weinberger HD, Grupp IL, Vikstrom KL, Iaccarino G, Koch WJ, Leinwand LA. Progression from hypertrophic to dilated cardiomyopathy in mice that express a mutant myosin transgene. Am J Physiol Heart Circ Physiol 2001; 280:H151-9. [PMID: 11123229 DOI: 10.1152/ajpheart.2001.280.1.h151] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A mouse model of hypertrophic cardiomyopathy (HCM) was created by expression of a cardiac alpha-myosin transgene including the R(403)Q mutation and a deletion of a segment of the actin-binding domain. HCM mice show early histopathology and hypertrophy, with progressive hypertrophy in females and ventricular dilation in older males. To test the hypothesis that dilated cardiomyopathy (DCM) is part of the pathological spectrum of HCM, we studied chamber morphology, exercise tolerance, hemodynamics, isolated heart function, adrenergic sensitivity, and embryonic gene expression in 8- to 11-mo-old male transgenic animals. Significantly impaired exercise tolerance and both systolic and diastolic dysfunction were seen in vivo. Contraction and relaxation parameters of isolated hearts were also decreased, and lusitropic responsiveness to the beta-adrenergic agonist isoproterenol was modestly reduced. Myocardial levels of the G protein-coupled beta-adrenergic receptor kinase 1 (beta-ARK1) were increased by more than twofold over controls, and total beta-ARK1 activity was also significantly elevated. Induction of fetal gene expression was also observed in transgenic hearts. We conclude that transgenic male animals have undergone cardiac decompensation resulting in a DCM phenotype. This supports the idea that HCM and DCM may be part of a pathological continuum rather than independent diseases.
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Affiliation(s)
- K Freeman
- Department of Molecular Cellular and Developmental Biology, University of Colorado, Boulder 80309-0347, Colorado, USA
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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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Guazzi M, Maltagliati A, Tamborini G, Celeste F, Pepi M, Muratori M, Berti M, Guazzi MD. How the left and right sides of the heart, as well as pulmonary venous drainage, adapt to an increasing degree of head-up tilting in hypertrophic cardiomyopathy: differences from the normal heart. J Am Coll Cardiol 2000; 36:185-93. [PMID: 10898433 DOI: 10.1016/s0735-1097(00)00698-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
OBJECTIVES We aimed to assess the differences in the adaptive response of patients with hypertrophic cardiomyopathy (HCM) compared with normal subjects, as well as any association with increased susceptibility to the test. BACKGROUND Diastolic function contributes importantly in the adaptation of the normal heart to head-up tilting. This mechanism may be disturbed by an impaired relaxation in HCM. METHODS Twenty-one male patients with HCM (46 +/- 6 years old) and 22 healthy men (44 +/- 8 years) were studied using Doppler echocardiography after 1 and 10 min of head-up tilting at 20 degrees, 40 degrees and 60 degrees. RESULTS In control subjects, tilting was associated with 1) a predominance of diastolic pulmonary venous flow and early left ventricular (LV) filling (atrium functioning as an open conduit); 2) right ventricular (RV) shrinkage; and 3) no LV dimensional variations. In patients with HCM, tilting was associated with 1) a prevalence of systolic pulmonary venous flow (atrium functioning as a reservoir in which filling depends on atrial relaxation and compliance) and late diastolic transmitral flow (atrium working as a booster pump); 2) LV shrinkage; and 3) no RV dimension variations. These mechanisms did not prevent stroke volume (SV) from decreasing at 40 degrees and 60 degrees in both groups. Because of a lower increase in heart rate (HR), a reduction in cardiac output (CO) was greater in patients with HCM. The responses were similar after 1 and 10 min of tilting in control subjects, whereas in patients, blood pressure (BP), SV and LV dimension fell more after 10 min. CONCLUSIONS Adaptation of the normal heart to tilting is based on a ventricular interaction and LV diastolic properties; HCM relies on left atrial diastolic and systolic functions. An inadequate HR reaction to a fall in BP and SV in HCM (depressed reflexogenic activity) contributes to making CO more vulnerable by greater and more prolonged displacements.
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Affiliation(s)
- M Guazzi
- Istituto di Cardiologia dell'Università degli Studi, Centro Cardiologico, IRCCS, Centro di Studio Ricerche Cardiovascolari del Consiglio Nazionale delle Ricerche, Milano, Italy.
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Schotten U, Koenigs B, Rueppel M, Schoendube F, Boknik P, Schmitz W, Hanrath P. Reduced myocardial sarcoplasmic reticulum Ca(2+)-ATPase protein expression in compensated primary and secondary human cardiac hypertrophy. J Mol Cell Cardiol 1999; 31:1483-94. [PMID: 10423346 DOI: 10.1006/jmcc.1999.0981] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Pathological intracellular calcium handling has been proposed to underlie the alterations of contractile behavior in hypertrophied myocardium. However, the myocardial protein expression of intracellular calcium transport proteins in compensated human left ventricular hypertrophy has not yet been studied. We investigated septal myocardial specimens of patients suffering from hypertrophic obstructive cardiomyopathy (n=14) or from acquired aortic valve stenosis (n=11) undergoing myectomy or aortic valve replacement, respectively. For comparison, we studied non-hypertrophied myocardium of six non-failing hearts which could not be transplanted for technical reasons. The myocardial density of the calcium release channel of the sarcoplasmic reticulum (SR) was determined by(3)H-ryanodine binding. Myocardial contents of SR Ca(2+)-ATPase, phospholamban, calsequestrin and Na(+)/Ca(2+)-exchanger were analysed by Western blot analysis. The myocardial SR calcium release channel density was not significantly different in hypertrophied and non-failing human myocardium. In both hypertrophic obstructive cardiomyopathy and in aortic valve stenosis, SR Ca(2+)-ATPase expression was reduced by about 30% compared to non-failing myocardium (P<0.05), whereas the expression of phospholamban, calsequestrin, and the Na(+)/Ca(2+)-exchanger was unchanged. The decrease of SR Ca(2+)-ATPase expression was still observable when related to its regulatory protein phospholamban or to the myosin content of the homogenates (P<0.05). Furthermore, the SR Ca(2+)-ATPase expression was inversely correlated to the septum thickness assessed by echocardiography, but not to age, cardiac index or outflow tract gradient. In primary as well as in secondary hypertrophied human myocardium, the expression of SR Ca(2+)-ATPase is reduced and inversely related to the degree of the hypertrophy. The diminished SR Ca(2+)-ATPase expression might result in reduced Ca(2+)reuptake into the SR and might contribute to altered contractile behavior in hypertrophied human myocardium.
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Affiliation(s)
- U Schotten
- Department of Cardiology, Medical Faculty, University of Technology, Pauwelsstrasse 30, Aachen, D-52057, Germany.
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Bhargava V, Shabetai R, Mathiäsen RA, Dalton N, Hunter JJ, Ross J. Loss of adrenergic control of the force-frequency relation in heart failure secondary to idiopathic or ischemic cardiomyopathy. Am J Cardiol 1998; 81:1130-7. [PMID: 9605055 DOI: 10.1016/s0002-9149(98)00133-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
This study was designed to determine whether the force-frequency effect on myocardial contractility, known to be importantly regulated by the adrenergic nervous system in experimental animals, can be enhanced by beta-adrenergic receptor stimulation in patients with heart failure. Animal experiments have demonstrated that the positive force-frequency relation in most mammals is subject to enhancement by beta-adrenergic receptor stimulation during exercise or infusion of a beta-receptor agonist. In animal models of heart failure, this regulatory mechanism generally is lost. The response to progressive increases in heart rate to 150 to 160 beats/min by right atrial pacing before and during dobutamine infusion was studied in 3 relatively normal subjects and in 5 patients with severe dilated cardiomyopathy. Left ventricular (LV) pressure and its first derivative (LV dP/dt(max)) were measured with a micromanometer, and the time constant of LV relaxation was assessed. The slopes of the relations between heart rate and LV dP/dt(max) in control subjects were positive at baseline and the mean slope increased substantially and significantly during dobutamine infusion. In patients with heart failure, the heart rate versus LV dP/dt(max) relations were depressed and flattened without a descending limb. Dobutamine infusion shifted this relation upward slightly, without increase in mean slope, indicating lack of amplification. The rate of isovolumic relaxation significantly decreased as heart rate increased at baseline and was further shortened by dobutamine. In patients with heart failure, a depressed and flattened relation between heart rate and LV dP/dt(max) (force-frequency effect) did not show the amplification of myocardial contractility by beta-adrenergic stimulation observed in the normal heart. This abnormality in control of the force-frequency relation undoubtedly plays an important role in the impairment of cardiac function during exercise in heart failure.
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