LV and myocyte structure and function after early recovery from tachycardia-induced cardiomyopathy

1995 ◽  
Vol 268 (2) ◽  
pp. H836-H847 ◽  
Author(s):  
F. G. Spinale ◽  
H. H. Holzgrefe ◽  
R. Mukherjee ◽  
S. R. Arthur ◽  
M. J. Child ◽  
...  

Left ventricular (LV) function and mass were measured in six conscious dogs at weekly intervals during the progression of tachycardia-induced dilated cardiomyopathy (DCM) and during a 1-mo recovery period from DCM (post-DCM). LV end-diastolic volume and LV wall stress increased and LV ejection fraction decreased with each week of pacing. Despite the increased LV wall stress, LV mass did not change during the progression of tachycardia DCM. One week post-DCM resulted in an improved LV ejection fraction and normalization of neurohormonal profiles. However, 1 wk post-DCM was accompanied by a 26% increase in LV mass and persistent LV chamber dilation. Isolated myocyte function was examined and compared with that in six normal control dogs. Myocyte percent and myocyte velocity of shortening were 19 and 32% lower, respectively, in the post-DCM group compared with controls. Thus termination of the tachycardia subsequent to the development of DCM resulted in persistent LV chamber dilation and abnormalities in myocyte contractile function. The improved LV pump function with early recovery from tachycardia-induced DCM was mediated by LV hypertrophy and a subsequent reduction in LV wall stress rather than a normalization of LV geometry and myocyte contractile function.

Author(s):  
Magnus T. Jensen ◽  
Kenneth Fung ◽  
Nay Aung ◽  
Mihir M. Sanghvi ◽  
Sucharitha Chadalavada ◽  
...  

Background: Diabetes mellitus (DM) is associated with increased risk of cardiovascular disease. Detection of early cardiac changes before manifest disease develops is important. We investigated early alterations in cardiac structure and function associated with DM using cardiovascular magnetic resonance imaging. Methods: Participants from the UK Biobank Cardiovascular Magnetic Resonance Substudy, a community cohort study, without known cardiovascular disease and left ventricular ejection fraction ≥50% were included. Multivariable linear regression models were performed. The investigators were blinded to DM status. Results: A total of 3984 individuals, 45% men, (mean [SD]) age 61.3 (7.5) years, hereof 143 individuals (3.6%) with DM. There was no difference in left ventricular (LV) ejection fraction (DM versus no DM; coefficient [95% CI]: −0.86% [−1.8 to 0.5]; P =0.065), LV mass (−0.13 g/m 2 [−1.6 to 1.3], P =0.86), or right ventricular ejection fraction (−0.23% [−1.2 to 0.8], P =0.65). However, both LV and right ventricular volumes were significantly smaller in DM, (LV end-diastolic volume/m 2 : −3.46 mL/m 2 [−5.8 to −1.2], P =0.003, right ventricular end-diastolic volume/m 2 : −4.2 mL/m 2 [−6.8 to −1.7], P =0.001, LV stroke volume/m 2 : −3.0 mL/m 2 [−4.5 to −1.5], P <0.001; right ventricular stroke volume/m 2 : −3.8 mL/m 2 [−6.5 to −1.1], P =0.005), LV mass/volume: 0.026 (0.01 to 0.04) g/mL, P =0.006. Both left atrial and right atrial emptying fraction were lower in DM (right atrial emptying fraction: −6.2% [−10.2 to −2.1], P =0.003; left atrial emptying fraction:−3.5% [−6.9 to −0.1], P =0.043). LV global circumferential strain was impaired in DM (coefficient [95% CI]: 0.38% [0.01 to 0.7], P =0.045). Conclusions: In a low-risk general population without known cardiovascular disease and with preserved LV ejection fraction, DM is associated with early changes in all 4 cardiac chambers. These findings suggest that diabetic cardiomyopathy is not a regional condition of the LV but affects the heart globally.


1978 ◽  
Vol 235 (6) ◽  
pp. H767-H775 ◽  
Author(s):  
G. A. Geffin ◽  
M. A. Vasu ◽  
D. D. O'Keefe ◽  
D. G. Pennington ◽  
A. J. Erdmann ◽  
...  

In dogs anesthetized with chloralose-urethan on right heart bypass, left ventricular (LV) performance was assessed at constant LV stroke work before and for up to 2.5 h after crystalloid hemodilution was established. Lowering the hematocrit from 43.3 +/- 1.3% to 13.6 +/- 1.7% (SE) did not significantly change LV end-diastolic pressure (LVEDP) initially. After 80 min LVEDP increased slightly by 1.7 +/- 0.6 cmH2O (P less than 0.05) at a stroke work of 17.3 +/- 2.3 g.m. The value of dP/dt did not change significantly throughout. When LV function curves were generated by increasing cardiac output, the stroke work attained at an LVEDP of 10 cmH2O decreased with hemodilution from 23.9 +/- 3.5 to 20.8 +/- 3.9 g.m (NS). LV wall water content increased with hemodilution, from which it could be calculated that there was an 18.6% increase in LV mass. Thus, despite an increase in LV external girth demonstrated by LV circumferential gauges, it is possible that increased wall thickness due to the water gain resulted in little change or an actual decrease in LV end-diastolic volume. Thus, profound hemodilution can be attained with only slight depression of LV performance.


1991 ◽  
Vol 261 (2) ◽  
pp. H308-H318 ◽  
Author(s):  
F. G. Spinale ◽  
M. Tomita ◽  
J. L. Zellner ◽  
J. C. Cook ◽  
F. A. Crawford ◽  
...  

Chronic supraventricular tachycardia (SVT) causes left ventricular (LV) dYsfunction and dilatation. Termination of SVT appears to improve symptoms of congestive heart failure. However, the structural events that occur during development and regression of SVT-induced cardiomyopathy are unknown. Accordingly, LV function (simultaneous echocardiogram-catheterization) and collagen content and distribution were measured in pigs (23-25 kg) assigned to three groups: 1) rapid atrial pacing (240 beats/min) for 3 wk (SVT, n = 10); 2) SVT for 3 wk, followed by deactivation of the pacemaker and a 4-wk recovery period (PST, n = 9); and 3) sham-operated controls (CON, n = 10). LV fractional shortening was 30 +/- 2% in CON, fell to 13 +/- 2% with SVT (P less than 0.05), and returned to CON values with PST (31 +/- 2%). SVT resulted in significantly increased LV end-diastolic dimension compared with CON (4.9 +/- 0.3 vs. 3.5 +/- 0.2 cm, P less than 0.05) and no change in LV wt/body wt (2.7 +/- 0.2 vs. 2.6 +/- 0.2 g/kg, P = 0.85). Termination of SVT (PST) resulted in development of hypertrophy, LV mass increased to 3.50 +/- 0.3 g/kg (P less than 0.05 vs. CON). With the use of pressure-dimension-thickness relations during diastole, the regional chamber stiffness constant (Kc) was computed. Kc was unchanged by SVT compared with CON (5.3 +/- 1.4 vs. 3.7 +/- 0.5, P greater than 0.35) but increased with PST (7.4 +/- 0.6, P less than 0.05). LV hydroxyproline content significantly fell with SVT compared with CON (2.24 +/- 0.58 vs. 2.68 +/- 0.45 mg/g dry wt, P less than 0.05, respectively) and significantly increased with PST (3.68 +/- 0.85 mg/g dry wt, P less than 0.05). With the use of transmission electron microscopy, collagen fibril diameter was reduced with SVT compared with CON (1.45 +/- 0.5 vs. 1.7 +/- 0.5 microns, P less than 0.05) and increased with PST (3.3 +/- 1.4 microns, P less than 0.05). Scanning electron microscopy revealed disruption of collagen struts between adjacent SVT myocytes and a thickened collagen weave with PST. Thus chronic SVT resulted in systolic and diastolic dysfunction and reduced collagen support of adjoining myocytes. Early recovery from SVT was associated with LV hypertrophy, increased collagen, and increased LV stiffness.


1985 ◽  
Vol 248 (4) ◽  
pp. H438-H444 ◽  
Author(s):  
N. F. Paradise ◽  
C. F. Pilati ◽  
W. R. Payne ◽  
J. A. Finkelstein

We sought to determine if left ventricular (LV) function of the heart from the adult, chronically obese animal is impaired. Hearts from 50 wk-old genetically obese female Zucker rats (624 +/- 13 g) and their lean littermate controls (275 +/- 5 g) were isolated during ether anesthesia, supported metabolically by retrograde aortic perfusion (6 ml/min, 35 degrees C) with physiological solution containing suspended canine erythrocytes (hematocrit, 20%), and the ventricles were paced at 180 beats/min. A distensible, fluid-filled balloon was placed in the LV, and pressure-volume (PV) relationships were obtained. The obese and lean end-diastolic PV curves were not different, and therefore the obese and lean LV chamber compliances were similar. Comparison of the systolic PV relationships demonstrated that the obese rat's heart had a greater pressure-generating capability, which probably was a reflection of its increased LV mass (0.96 +/- 0.03 vs. 0.72 +/- 0.02 g). The calculated average meridional (or circumferential) peak systolic wall stress in the LV of the obese rat's heart, however, was significantly reduced compared with control. This diminished ability to develop systolic stress from the same end-diastolic volumes suggests that the hypertrophied LV of the middle-aged obese rat's heart is dilated or that its contractility is depressed, or both.


2020 ◽  
Author(s):  
Runfeng Zhang ◽  
Jiang Yu ◽  
Ningkun Zhang ◽  
Wensong Li ◽  
Jisheng Wang ◽  
...  

Abstract Objective: Our aimed to evaluate efficacy and safety of intracoronary autologous bone morrow mesenchymal stem cells (BM-MSCs) transplantation in patients with ST-segment elevation myocardial infarction(STEMI). Methods: In this randomised, single-blind, controlled trial, patients with STEMI (aged 39-76 years) were enrolled at 6 centers in Beijing (the People's Liberation Army Navy General Hospital, Beijing Armed Police General Hospital, Chinese People's Liberation Army General Hospital, Beijing Huaxin Hospital, Beijing Tongren Hospital, Beijing Chaoyang Hospital West Hospital). Patients underwent optimum medical treatment and percutaneous coronary intervention,and were randomly assigned in a 1:1 ratio to BM-MSCs group or control group. The primary endpoint was change of myocardial viability at 6 months' follow-up and left-ventricular (LV) function at 12 months' follow-up.The secondary endpoints were incidence of cardiovascular event, total mortality and adverse event at 12 months' follow-up. The myocardial viability assessed by single- photon emission tomography (SPECT). The left ventricular ejection fraction was used to assess LV function. All patients underwent dynamic ECG and laboratory evaluations. This trial is registered with ClinicalTrails.gov, number NCT04421274. Results: Between March , 2008, and July , 2010, 43 patients were randomly assigned to BM-MSCs group (n=21)or control group(n=22) and followed up for 12 months. LV ejection fraction increased from baseline to 12 months in the BM-MSCs group and control group ( mean baseline-adjusted BM-MSCs treatment differences in LV ejection fraction 4.8% (SD 9.0) and mean baseline-adjusted control group treatment differences in LV ejection fraction 5.8% (SD 6.04) ). After 6 months of follow-up, there was no significant improvement in myocardial metabolic activity in the BM-MSCs group before and after transplantation. however,there was no statistically significant difference between the two groups in the change of LV ejection fraction (p=0.30) and myocardial metabolic activity(p>0.05). We noticed that ,after 12 months of follow-up, except for 1 death and 1 coronary microvascular embolism in the BM-MSCs group, no other events occurred and Alanine transaminase(ALT) and C-reactive protein(CRP) in BM-MSCs group were significantly lower than that in control group. Conclusions: It is unreasonable to speculate that intracoronary transfer of autologous bone marrow MSCs could augment recovery of LV function and myocardial viability after acute myocardial infarction.Trial registration: clinicaltrials,NCT04421274. Registered 06,08,2020- Retrospectively registered, https://register.clinicaltrials.gov/NCT04421274.


PLoS ONE ◽  
2021 ◽  
Vol 16 (12) ◽  
pp. e0259450
Author(s):  
Maria F. Paton ◽  
John Gierula ◽  
Judith E. Lowry ◽  
David A. Cairns ◽  
Kieran Bose Rosling ◽  
...  

Background Pacemakers are widely utilised to treat bradycardia, but right ventricular (RV) pacing is associated with heightened risk of left ventricular (LV) systolic dysfunction and heart failure. We aimed to compare personalised pacemaker reprogramming to avoid RV pacing with usual care on echocardiographic and patient-orientated outcomes. Methods A prospective phase II randomised, double-blind, parallel-group trial in 100 patients with a pacemaker implanted for indications other than third degree heart block for ≥2 years. Personalised pacemaker reprogramming was guided by a published protocol. Primary outcome was change in LV ejection fraction on echocardiography after 6 months. Secondary outcomes included LV remodeling, quality of life, and battery longevity. Results Clinical and pacemaker variables were similar between groups. The mean age (SD) of participants was 76 (+/-9) years and 71% were male. Nine patients withdrew due to concurrent illness, leaving 91 patients in the intention-to-treat analysis. At 6 months, personalised programming compared to usual care, reduced RV pacing (-6.5±1.8% versus -0.21±1.7%; p<0.01), improved LV function (LV ejection fraction +3.09% [95% confidence interval (CI) 0.48 to 5.70%; p = 0.02]) and LV dimensions (LV end systolic volume indexed to body surface area -2.99mL/m2 [95% CI -5.69 to -0.29; p = 0.03]). Intervention also preserved battery longevity by approximately 5 months (+0.38 years [95% CI 0.14 to 0.62; p<0.01)) with no evidence of an effect on quality of life (+0.19, [95% CI -0.25 to 0.62; p = 0.402]). Conclusions Personalised programming in patients with pacemakers for bradycardia can improve LV function and size, extend battery longevity, and is safe and acceptable to patients. Trial registration ClinicalTrials.gov identifier: NCT03627585.


Author(s):  
Savvas Toumanidis ◽  
John Agrios ◽  
Anna Kaladaridou ◽  
Dimitrios Bramos ◽  
Elias Skaltsiotes ◽  
...  

Aim: Early intravenous use of b-blockers within the first hours of STEMI is less firmly established. The aim of this study was to evaluate the effect of esmolol on left ventricular (LV) haemodynamic, rotational and strain parameters in intact myocardium and early post an experimental acute anterior myocardial infarction (MI). Methods: In 20 healthy pigs LV torsional and strain parameters were calculated from basal and apical short axis epicardial planes with speckle tracking technique using EchoPAC platform. LV measurements at baseline and during esmolol infusion (0.5 mg/kg for 1 min, then 0.05 mg/kg/min for 5 min) were compared in intact myocardium and repeated without b-blocker and during esmolol infusion 2 hours post LAD ligation. Results: LV function was highly dependent on the esmolol infusion, in the intact and even more in the infarcted myocardium. LV ejection fraction, LV dP/dtmax and LV end-systolic pressure decreased significantly, a deterioration produced by the administration of esmolol. Torsion-twist and untwisting rate also presented significant reduction in correlation with ejection fraction and cardiac output, appearing to affect especially the apex torsional and strain parameters. Conclusion: Esmolol infusion significantly reduces LV haemodynamic, torsional and strain parameters in intact myocardium and early post MI. These results suggest that early intravenous use of esmolol in patients with STEMI is risky and it is prudent to wait for the patient to stabilize before starting esmolol.


2021 ◽  
Vol 23 (Supplement_G) ◽  
Author(s):  
Giovanni Diana ◽  
Laura Manfredonia ◽  
Monica Filice ◽  
Emanuele Ravenna ◽  
Francesca Graziani ◽  
...  

Abstract Aims Global longitudinal strain (GLS) is a hallmark of cardiac damage in mitral regurgitation (MR). GLS &gt; −18% in patients with severe organic MR (OMR) and normal LV ejection fraction (LVEF) is an independent predictor of postoperative LV dysfunction. While it is known that GLS is impaired in less than severe functional ischaemic MR (FMR), the value of GLS in less than severe OMR is not known. We aimed to determine prevalence and determinants of any GLS impairment in OMR, in comparison to FMR. Methods We retrospectively evaluated 51 consecutive patients (33 OMR and 18 FMR) with mild-to-moderate, moderate and moderate-to-severe MR (Table*). Overall, GLS was higher in OMR than FMR (17.9±4.5 vs. 10.3±5.3, P&lt;0.001), with rate of impairment of 45% in OMR and 89% in FMR (P= 0.0024). Results However, no significant difference was found in GLS between mild-to-moderate, moderate and moderate-to-severe MR patients within OMR (17.7±4.7 vs. 16.9±3.9 vs. 22.4±3, respectively, P&gt;0.05), as well as FMR (9.8±6.6 vs. 10.7±5.3 vs. 10.4±5.3, respectively, P&gt;0.05) groups. GLS correlated directly with left ventricular (LV) ejection fraction (EF) in both OMR (r=0.69, P&lt;0.001) and FMR (r=0.90, P&lt;0.001), and inversely with LV mass indexed for body surface area (LVMi) in both OMR (r = −0.50, P=0.005) and FMR (r = −0.48, P=0.042). While correlation with LVEF was better for FMR than OMR (Z − 1.95, P=0.026), correlation with LVMi was similar for OMR and FMR groups (Z − 0.082, P&gt;0.05). Conclusions In patients with OMR, GLS may be reduced, despite normal LVEF, in less than severe MR. Prevalence and degree of GLS impairment in OMR is less than in FMR. In OMR, as well as in FMR, GLS impairment is independent of entity of MR, but rather correlates with LVMi, maybe reflecting impact of myocardial fibrosis derived by increased LVMi on GLS.


Heart ◽  
2020 ◽  
pp. heartjnl-2020-316992
Author(s):  
Paul A Grayburn ◽  
Milton Packer ◽  
Anna Sannino ◽  
Gregg W Stone

Secondary (functional) mitral regurgitation (SMR) most commonly arises secondary to left ventricular (LV) dilation/dysfunction. The concept of disproportionately severe SMR was proposed to help explain the different results of two randomised trials of transcatheter edge-to-edge mitral valve repair (TEER) versus medical therapy. This concept is based on the fact that effective regurgitant orifice area (EROA) depends on LV end-diastolic volume (LVEDV), ejection fraction, regurgitant fraction and the velocity-time integral of SMR. This review focuses on the haemodynamic framework underlying the concept and the myths and misconceptions arising from it. Each component of EROA/LVEDV is prone to measurement error which can result in misclassification of individual patients. Moreover, EROA is typically measured at peak systole rather than its mean value over the duration of MR. This can result in physiologically impossible values of EROA or regurgitant volume. Although the EROA/LVEDV ratio (1) emphasises that grading MR severity needs to consider LV size and function and (2) helps explain the different outcomes between COAPT and MITRAFR, there are important factors that are not included. Among these are left atrial compliance, LV pressure and ejection fraction, pulmonary hypertension, right ventricular function and tricuspid regurgitation. Because medical therapy can reduce LV volumes and improve both LV function and SMR severity, the key to patient selection is forced titration of neurohormonal antagonists to the target doses that have been proven in clinical trials (along with cardiac resynchronisation when appropriate). Patients who continue to have symptomatic severe SMR after doing so should be considered for TEER.


2021 ◽  
Vol 36 (Supplement_1) ◽  
Author(s):  
João Carvão ◽  
Adriana Fernandes ◽  
Rita Veríssimo ◽  
Rita Calça ◽  
Ana Rita Martins ◽  
...  

Abstract Background and Aims N-terminal fragment of B-type natriuretic peptide (NT-proBNP) can reflect changes in hydration status and may help the nephrologist to estimate it. Fluid volume overload is a major concern in dialysis patients, and it is associated with increased cardiovascular risk and death. This study evaluated the relationship between serum NT-proBNP levels and left ventricular (LV) dysfunction and extra-cellular excess water in peritoneal dialysis patients. Method We conducted a cross-sectional study of 60 peritoneal dialysis (PD) patients. Incident and prevalent patients were included. Echocardiography was performed using HDI 5000, allowing M-mode, two-dimensional measurement. A multifrequency bioimpedance (BIA) analyzer was used. Overhydration (OH) was defined as an extra-cellular water (ECW)/total body water (TBW) over 15%. Clinical and biochemical variables were also analysed. Results A total of 60 patients were evaluated (male 60% (n=36), mean age was 55,8 ± 15,3 years, BMI 25.9 ± 3.9 kg/m2 and 31.7% (n=19) had diabetes mellitus (DM). Median PD vintage was 21 months, automated PD 30%, 8.3% (n=5) were anuric and 10% (n=6) were overhydrated. The median serum NT-proBNP level was 1071 pg/mL. LV mass index and LV ejection fraction were 129.0 ± 51.1 g/m2 and 62.8 ± 13.0%, respectively. The median excess volume overload was 0.9L. Serum NT-proBNP levels correlated positively with, diabetes (r=0.27, p=0.04), isquemic cardiopathy (r=0.37, p=0.01), LV mass index (r=0.48, p=0.001) and extracellular water (r=0.31, p=0.02) and negatively with LV ejection fraction (r= -0.81, p=0.01). In a multivariable analysis, in a model adjusted to time in DP, diabetes, residual diuresis, isquemic cardiopathy and left ventricle mass index, NT-proBNP &gt; 1600 pg/mL was associated with patient overhidratation (exp (B) 1,44, 95% CI 0,15-2.73). No statistical difference was observed considering nutritional parameters, peritoneal transport, dialysis efficacy and NT-proBNP. Conclusion In this population, higher levels of NT-proBNP were associated with overhydration status and left ventricular dysfunction. Therefore, BIA and NT-proBNP may be complementary to clinical evaluation of PD patients. BIA results can be affected by malnutrition with loss of cell mass according to some studies. In our population NT-proBNP is not affected by nutritional status and therefore can also be used as a congestive marker in malnourished patients. Longitudinal application of BIA could be a useful clinical tool to evaluate adequacy in PD patients.


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