Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 123
Filtrar
1.
Eur Heart J Cardiovasc Imaging ; 21(6): 619-628, 2020 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-32031587

RESUMO

AIMS : Investigating the acute impact of cardiac resynchronization therapy (CRT) on regional myocardial work distribution in the left ventricle (LV) and to which extent it is related to long-term reverse remodelling. METHODS AND RESULTS : One hundred and thirty heart failure patients, referred for CRT implantation, were recruited in our prospective multicentre study. Regional myocardial work was calculated from non-invasive segmental stress-strain loop area before and immediately after CRT. The magnitude of volumetric reverse remodelling was determined from the change in LV end-systolic volume, 11 ± 2 months after implantation. CRT caused acute redistribution of myocardial work across the LV, with an increase in septal work, and decrease in LV lateral wall work (all P < 0.05). Amongst all LV walls, the acute change in work in the septum and lateral wall of the four-chamber view correlated best and significantly with volumetric reverse remodelling (r = 0.62, P < 0.0001), with largest change seen in patients with most volumetric reverse remodelling. In multivariate linear regression analysis, including conventional parameters, such as pre-implant QRS morphology and duration, LV ejection fraction, ischaemic origin of cardiomyopathy, and the redistribution of work across the septal and lateral walls, the latter appeared as the strongest determinant of volumetric reverse remodelling after CRT (model R2 = 0.414, P < 0.0001). CONCLUSION : The acute redistribution of regional myocardial work between the septal and lateral wall of the LV is an important determinant of reverse remodelling after CRT implantation. Our data suggest that the treatment of the loading imbalance should, therefore, be the main aim of CRT.

2.
Artigo em Inglês | MEDLINE | ID: mdl-31954643

RESUMO

OBJECTIVES: The purpose of this study was to investigate how LBBB and CRT modify RV free wall function by direct ventricular interaction. BACKGROUND: Right ventricular (RV) function influences prognosis in patients with left bundle branch block (LBBB) and cardiac resynchronization therapy (CRT). There is, however, limited insight into how LBBB and CRT affect RV function. METHODS: In 24 patients with LBBB with nonischemic cardiomyopathy, RV and left ventricular (LV) strain by speckle-tracking echocardiography was measured before and after CRT. Underlying mechanisms were studied in 16 anesthetized dogs with ultrasonic dimension crystals and micromanometers. RESULTS: Patients with LBBB demonstrated distinct early systolic shortening in the RV free wall, which coincided with the typical abnormal early systolic septal shortening. In animals, this RV free wall contraction pattern resulted in reduced myocardial work as a large portion of the shortening occurred against low pressure during early systole, coinciding with abnormal leftward septal motion. RV systolic function was maintained by vigorous contraction in the late-activated LV lateral wall, which pushed the septum toward the RV. CRT reduced abnormal septal motion and increased RV free wall work because there was less inefficient shortening against low pressure. CONCLUSIONS: LBBB reduces workload on the RV free wall because of abnormal septal motion and delayed activation of the LV lateral wall. Restoring septal and LV function by CRT increases workload in RV free wall and may explain why patients with RV failure respond poorly to CRT. (Contractile Reserve in Dyssynchrony: A Novel Principle to Identify Candidates for Cardiac Resynchronization Therapy [CRID-CRT]; NCT02525185).

3.
J Appl Physiol (1985) ; 128(4): 729-738, 2020 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-31999529

RESUMO

We investigated whether tachycardia in left bundle branch block (LBBB) decreases left ventricular (LV) diastolic distensibility and increases diastolic pressures due to incomplete relaxation, and if cardiac resynchronization therapy (CRT) modifies this response. Thirteen canines were studied at baseline heart rate (120 beats/min) and atrial paced tachycardia (180 beats/min) before and after induction of LBBB and during CRT. LV and left atrial pressures (LAP) were measured by micromanometers and dimensions by sonomicrometry. The time constant τ of exponential pressure decay and degree of incomplete relaxation at mitral valve opening (MVO) and end diastole (ED) based on extrapolation of the exponential decay were assessed. Changes in LV diastolic distensibility were investigated using the LV transmural pressure-volume (PV) relation. LBBB caused prolongation of τ (P < 0.03) and increased the degree of incomplete relaxation during tachycardia at MVO (P < 0.001) and ED (P = 0.08) compared with normal electrical activation. This was associated with decreased diastolic distensibility seen as upward shift of the PV relation at MVO by 18.4 ± 7.0 versus 12.0 ± 5.0 mmHg, at ED by 9.8 ± 2.3 versus 4.7 ± 2.3 mmHg, and increased mean LAP to 11.4 ± 2.7 versus 8.5 ± 2.6 mmHg, all P < 0.006. CRT shifted the LV diastolic PV relation downwards during tachycardia, reducing LAP and LV diastolic pressures (P < 0.03). Tachycardia in LBBB reduced LV diastolic distensibility and increased LV diastolic pressures due to incomplete relaxation, whereas CRT normalized these effects. Clinical studies are needed to determine whether a similar mechanism contributes to dyspnea and exercise intolerance in LBBB and if effects of CRT are heart rate dependent.NEW & NOTEWORTHY Compared with normal electrical conduction, tachycardia in left bundle branch block resulted in incomplete relaxation during filling, particularly of the late activated left ventricular lateral wall. This further resulted in reduced left ventricular diastolic distensibility and elevated diastolic pressures and thus amplified the benefits of cardiac resynchronization therapy in this setting.

4.
JACC Cardiovasc Imaging ; 13(1 Pt 2): 272-282, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31202741

RESUMO

Diastolic dysfunction is a key factor in the pathogenesis of heart failure. Around 50% of cases of heart failure, the hemodynamic correlate of which is increased left ventricular filling pressure, are caused by diastolic dysfunction in the setting of apparently normal systolic function. Due to its high prevalence, diastolic dysfunction is often recognized as an incidental finding. Many patients have Doppler echocardiographic evidence of impaired diastolic function but do not have any symptoms of heart failure at rest. In many of these patients, symptoms of diastolic dysfunction occur only during exercise, as left ventricular filling pressure is normal at rest, but increases with exercise. This implies that filling pressures should also be measured during exercise. The diastolic stress test refers to the evaluation of diastolic function, either invasively or noninvasively, during exercise. This review focuses on the clinical need for diastolic stress testing, both invasively and noninvasively.

5.
6.
Eur Heart J Cardiovasc Imaging ; 21(2): 143-153, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31599327

RESUMO

AIMS : Regional myocardial work may be assessed by pressure-strain analysis using a non-invasive estimate of left ventricular pressure (LVP). Strain by speckle tracking echocardiography (STE) is not always accessible due to poor image quality. This study investigated the estimation of regional myocardial work from strain by feature tracking (FT) cardiac magnetic resonance (CMR) and non-invasive LVP. METHODS AND RESULTS : Thirty-seven heart failure patients with reduced ejection fraction, left bundle branch block (LBBB), and no myocardial scar were compared to nine controls without LBBB. Circumferential strain was measured by FT-CMR in a mid-ventricular short-axis cine view, and longitudinal strain by STE. Segmental work was calculated by pressure-strain analysis. Twenty-five patients underwent 18F-fluorodeoxyglucose (FDG) positron emission tomography. Segmental values were reported as percentages of the segment with maximum myocardial FDG uptake. In LBBB patients, net CMR-derived work was 51 ± 537 (mean ± standard deviation) in septum vs. 1978 ± 1084 mmHg·% in the left ventricular (LV) lateral wall (P < 0.001). In controls, however, there was homogeneous work distribution with similar values in septum and the LV lateral wall (non-significant). Reproducibility was good. Segmental CMR-derived work correlated with segmental STE-derived work and with segmental FDG uptake (average r = 0.71 and 0.80, respectively). CONCLUSION : FT-CMR in combination with non-invasive LVP demonstrated markedly reduced work in septum compared to the LV lateral wall in patients with LBBB. Work distribution correlated with STE-derived work and energy demand as reflected in FDG uptake. These results suggest that FT-CMR in combination with non-invasive LVP is a relevant clinical tool to measure regional myocardial work.

7.
Hypertension ; 75(1): 23-32, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31786973

RESUMO

Current cardiovascular pharmacotherapy targets maladaptive overactivation of the renin-angiotensin-aldosterone system (RAAS), which occurs throughout the continuum of cardiovascular disease spanning from hypertension to heart failure with reduced ejection fraction. Over the past 16 years, 4 prospective, randomized, placebo-controlled clinical trials using candesartan, perindopril, irbesartan, and spironolactone in patients with heart failure with preserved ejection fraction (HFpEF) failed to demonstrate increased efficacy of RAAS blockade added to guideline-directed medical therapy. We reappraise these trials and their weaknesses, which precluded statistically significant findings. Recently, dual-acting RAAS blockade with sacubitril-valsartan relative to stand-alone valsartan failed to improve outcome in the PARAGON-HF trial (Efficacy and Safety of LCZ696 Compared with Valsartan, on Morbidity and Mortality in Heart Failure Patients With Preserved Ejection Fraction). The majority of patients with HFpEF experience hypertension, frequently with subclinical left ventricular dysfunction, contributed to by comorbidities such as coronary disease, diabetes mellitus, overweight, and atrial fibrillation. Contrasting the findings in HFpEF, trials evaluating RAAS blockade on either side of HFpEF on the cardiovascular continuum in patients with high-risk hypertension and heart failure with reduced ejection fraction, respectively, showed positive outcomes. We do not have a biologically plausible explanation for such divergent efficacy of RAAS blockade. Based on considerations of well-established clinical efficacy in hypertension and heart failure with reduced ejection fraction and the shortcomings of aforementioned clinical trials in HFpEF, we argue that RAAS blockers including MRAs (mineralocorticoid receptor antagonists; aldosterone antagonists) should be used in the treatment of patients with HFpEF.

9.
JACC Cardiovasc Imaging ; 12(10): 2097-2098, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31601383
10.
Am Heart J ; 212: 53-63, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-30951976

RESUMO

BACKGROUND: Recent studies have shown that myocardial constructive work (CW) assessed by pressure-strain loops (PSLs) is an independent predictor of a volumetric response to cardiac resynchronization therapy (CRT). The aim of this study was to evaluate the role of CW in predicting the cardiac outcome of heart failure patients undergoing CRT. METHODS: This is a retrospective study including 166 CRT candidates (ejection fraction [EF] ≤35%, QRS duration ≥120 milliseconds). Two-dimensional standard echocardiography and speckle-tracking echocardiography were performed before CRT and at 6-month follow-up. PSLs were used to assess myocardial CW. RESULTS: After a median follow-up of 4 years (range 1.3-5 years), cardiac death occurred in 14 patients (8%). A multivariable Cox regression analysis including age, coronary artery disease, and septal flash showed that CW≤888 mm Hg% was the only independent predictor of cardiac mortality (hazard ratio 4.23, 95% CI 1.08-16.5, P = .03). After 6 months of CRT, a 15% reduction in left ventricular end-systolic volume was observed in 118 (71%) patients, and a CRT volumetric response was identified. Among CRT responders, the concomitant presence of CW ≤888 mm Hg% identified a subgroup of patients at high risk of cardiac death (P = .04 in the log-rank test). The addition of CW ≤888 mm Hg% to a model including age, coronary artery disease, septal flash, and CRT response caused a significant increase in model power for the prediction of cardiac death (χ2: 12.6 vs 25.7, P = .02). CONCLUSIONS: The estimation of left ventricular CW by PSLs is a relatively novel tool that allows for the prediction of cardiac outcome in CRT candidates.


Assuntos
Terapia de Ressincronização Cardíaca/métodos , Eletrocardiografia , Insuficiência Cardíaca/terapia , Contração Miocárdica/fisiologia , Seleção de Pacientes , Volume Sistólico/fisiologia , Função Ventricular Esquerda/fisiologia , Idoso , Ecocardiografia/métodos , Feminino , Seguimentos , Insuficiência Cardíaca/mortalidade , Insuficiência Cardíaca/fisiopatologia , Humanos , Masculino , Pessoa de Meia-Idade , Noruega/epidemiologia , Prognóstico , Estudos Retrospectivos , Taxa de Sobrevida/tendências , Fatores de Tempo
11.
Tidsskr Nor Laegeforen ; 139(6)2019 Mar 26.
Artigo em Norueguês | MEDLINE | ID: mdl-30917641

RESUMO

BACKGROUND: Approximately one half of all patients with heart failure have normal ejection fraction in the left ventricle, and heart failure is attributed to stiffness of the cardiac muscle. The most common cause is hypertension with ventricular hypertrophy. MATERIAL AND METHOD: Literature searches were conducted in PubMed. After we made our selection, a total of 15 articles on heart failure with normal ejection fraction were included. In addition, we included nine articles from our own literature archive. RESULTS: The diagnosis of heart failure with normal ejection fraction presupposes clinical findings consistent with heart failure and objective signs of diastolic dysfunction. The main objective sign is increased left ventricular filling pressure estimated by echocardiography. Ventricular hypertrophy and increased natriuretic peptides support the diagnosis. INTERPRETATION: Underlying conditions and symptoms are treated, and in general the same drugs are used as for heart failure with reduced ejection fraction.


Assuntos
Insuficiência Cardíaca , Volume Sistólico/fisiologia , Doenças Cardiovasculares/complicações , Doenças Cardiovasculares/tratamento farmacológico , Ecocardiografia , Insuficiência Cardíaca/diagnóstico , Insuficiência Cardíaca/tratamento farmacológico , Insuficiência Cardíaca/etiologia , Insuficiência Cardíaca/fisiopatologia , Humanos , Hipertensão/complicações , Hipertensão/tratamento farmacológico , Hipertrofia Ventricular Esquerda/complicações , Hipertrofia Ventricular Esquerda/tratamento farmacológico
12.
JACC Cardiovasc Imaging ; 12(12): 2402-2413, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30772230

RESUMO

OBJECTIVES: This study sought to investigate how regional left ventricular (LV) function modifies septal motion in left bundle branch block (LBBB). BACKGROUND: In LBBB, the interventricular septum often has marked pre-ejection shortening, followed by immediate relengthening (rebound stretch). This motion, often referred to as septal flash, is associated with positive response to cardiac resynchronization therapy (CRT). METHODS: In 10 anesthetized dogs, we induced LBBB by radiofrequency ablation and occluded the circumflex (CX) (n = 10) and left anterior descending (LAD) (n = 6) coronary arteries, respectively. Myocardial dimensions were measured by sonomicrometry and myocardial work by pressure-segment length analysis. In 40 heart failure patients with LBBB, including 20 with post-infarct scar and 20 with nonischemic cardiomyopathy, myocardial strain was measured by speckle-tracking echocardiography and myocardial work by pressure-strain analysis. Scar was assessed by cardiac magnetic resonance imaging with late gadolinium enhancement. RESULTS: During LBBB, each animal showed typical septal flash with pre-ejection shortening and rebound stretch, followed by reduced septal systolic shortening (p < 0.01). CX occlusion caused LV lateral wall dysfunction and abolished septal flash due to loss of rebound stretch (p < 0.0001). Furthermore, CX occlusion restored septal systolic shortening to a similar level as before induction of LBBB and substantially improved septal work (p < 0.001). LAD occlusion, however, accentuated septal flash by increasing rebound stretch (p < 0.05). Consistent with the experimental findings, septal flash was absent in patients with LV lateral wall scar due to lack of rebound stretch (p < 0.001), and septal systolic shortening and septal work far exceeded values in nonischemic cardiomyopathy (p < 0.0001). Septal flash was present in most patients with anteroseptal scar. CONCLUSIONS: LV lateral wall dysfunction and scar abolished septal flash and markedly improved septal function in LBBB. Therefore, function and scar in the LV lateral wall should be taken into account when septal motion is used to evaluate dyssynchrony.

13.
Circ Cardiovasc Imaging ; 12(1): e008122, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-30632389

RESUMO

BACKGROUND: Assessment of left ventricular (LV) filling pressure is among the important components of a comprehensive echocardiographic report. Previous studies noted wide limits of agreement using 2009 American Society of Echocardiography/European Association of Echocardiography guidelines, but reproducibility of 2016 guidelines update in estimating LV filling pressure is unknown. METHODS: Echocardiographic and hemodynamic data were obtained from 50 patients undergoing cardiac catheterization for clinical indications. Clinical and echocardiographic findings but not invasive hemodynamics were provided to 4 groups of observers, including experienced echocardiographers and cardiology fellows. Invasively acquired LV filling pressure was the gold standard. RESULTS: In group I of 8 experienced echocardiographers from the guidelines writing committee, sensitivity for elevated LV filling pressure was 92% for all observers, and specificity was 93±6%. Fleiss κ-value for the agreement in group I was 0.80. In group II of 4 fellows in training, sensitivity was 91±2%, and specificity was 95±2%. Fleiss κ-value for the agreement in group II was 0.94. In group III of 9 experienced echocardiographers who had not participated in drafting the guidelines, sensitivity was 88±5%, and specificity was 91±7%. Fleiss κ-value for the agreement in group III was 0.76. In group IV of 7 other fellows, sensitivity was 91±3%, and specificity was 92±5%. Fleiss κ-value for the agreement in group IV was 0.89. CONCLUSIONS: There is a good level of agreement and accuracy in the estimation of LV filling pressure using the American Society of Echocardiography/European Association of Cardiovascular Imaging 2016 recommendations update, irrespective of the experience level of the observer.


Assuntos
Ecocardiografia Doppler/normas , Cardiopatias/diagnóstico por imagem , Ventrículos do Coração/diagnóstico por imagem , Guias de Prática Clínica como Assunto/normas , Função Ventricular Esquerda , Pressão Ventricular , Idoso , Feminino , Cardiopatias/fisiopatologia , Ventrículos do Coração/fisiopatologia , Humanos , Masculino , Pessoa de Meia-Idade , Variações Dependentes do Observador , Valor Preditivo dos Testes , Reprodutibilidade dos Testes
14.
Trends Cardiovasc Med ; 29(6): 335-342, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-30401603

RESUMO

The impact of left bundle branch block (LBBB) on cardiac mechanical function ranges from minimal effect in some patients to marked reduction in left ventricular (LV) systolic function in others. It appears that this variability in part reflects differences in anatomical location of the bundle block. In most patients with LBBB and congestive heart failure, however, there is associated cardiac disease such as cardiomyopathies or coronary artery disease which contributes to LV dysfunction. The mechanism of harmful effect of LBBB on cardiac function is in-coordinated ventricular contractions which result in LV contractile inefficiency. Septal contribution to LV systolic function is lost or attenuated and an excessive workload is placed on the LV free wall which responds with remodeling and in some cases it decompensates. The magnitude of the contractile inefficiency depends on the extent of electrical conduction delay and degree of associated heart disease. Another mechanism, which in many patients contributes to cardiac dysfunction in LBBB, is mitral regurgitation due to in-coordinated contractions of the papillary muscles and altered mitral valve function due to LV remodeling. Potentially, reduced LV filling time due to prolonged LV systole may contribute to cardiac dysfunction, but there is limited knowledge about the clinical importance of this mechanism. In LBBB there is typically reduced septal perfusion, probably not as a sign of ischemia, but reflecting physiologic autoregulation of coronary flow in response to reduced septal work that reduces metabolic demand. Future studies should explore how current insights into mechanisms of cardiac mechanical effects of LBBB can be incorporated into decision algorithms for selection of patients for cardiac resynchronization therapy, as well as how to manage patients with LBBB and preserved LV function.


Assuntos
Bloqueio de Ramo/complicações , Insuficiência Cardíaca/etiologia , Insuficiência da Valva Mitral/etiologia , Disfunção Ventricular Esquerda/etiologia , Potenciais de Ação , Idoso , Idoso de 80 Anos ou mais , Animais , Fascículo Atrioventricular/fisiopatologia , Bloqueio de Ramo/diagnóstico , Bloqueio de Ramo/fisiopatologia , Bloqueio de Ramo/terapia , Terapia de Ressincronização Cardíaca , Tomada de Decisão Clínica , Progressão da Doença , Feminino , Insuficiência Cardíaca/diagnóstico , Insuficiência Cardíaca/fisiopatologia , Insuficiência Cardíaca/terapia , Frequência Cardíaca , Humanos , Masculino , Pessoa de Meia-Idade , Valva Mitral/fisiopatologia , Insuficiência da Valva Mitral/diagnóstico , Insuficiência da Valva Mitral/fisiopatologia , Insuficiência da Valva Mitral/terapia , Seleção de Pacientes , Prognóstico , Medição de Risco , Fatores de Risco , Disfunção Ventricular Esquerda/diagnóstico , Disfunção Ventricular Esquerda/fisiopatologia , Disfunção Ventricular Esquerda/terapia , Função Ventricular Esquerda , Remodelação Ventricular
16.
Europace ; 21(2): 347-355, 2019 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-30418572

RESUMO

Aims: There are conflicting data and no consensus on how to measure acute response to cardiac resynchronization therapy (CRT). This study investigates, which contractility indices are best markers of acute CRT response. Methods and results: In eight anaesthetized dogs with left bundle branch block, we measured left ventricular (LV) pressure by micromanometer and end-diastolic volume (EDV) and end-systolic volume (ESV) by sonomicrometry. Systolic function was measured as LV ejection fraction (EF), peak rate of LV pressure rise (LV dP/dtmax) and as a gold standard of contractility, LV end-systolic elastance (Ees), and volume axis intercept (V0) calculated from end-systolic pressure-volume relations (ESPVR). Responses to CRT were compared with inotropic stimulation by dobutamine. Both CRT and dobutamine caused reduction in ESV (P < 0.01) and increase in LV dP/dtmax (P < 0.05). Both interventions shifted the ESPVR upwards indicating increased contractility, but CRT which reduced V0 (P < 0.01), caused no change in Ees. Dobutamine markedly increased Ees, which is the typical response to inotropic stimulation. Preload (EDV) was decreased (P < 0.01) by CRT, and there was no change in EF. When adjusting for the reduction in preload, CRT increased EF (P = 0.02) and caused a more marked increase in LV dP/dtmax (P < 0.01). Conclusion: Increased contractility by CRT could not be identified by Ees, which is a widely used reference method for contractility. Furthermore, reduction in preload by CRT attenuated improvement in contractility indices such as EF and LV dP/dtmax. These results suggest that changes in LV volume may be more sensitive markers of acute CRT response than conventional contractility indices.

17.
JACC Cardiovasc Imaging ; 12(6): 967-977, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-29361486

RESUMO

OBJECTIVES: This study sought to investigate the hypothesis that patients with left bundle branch block (LBBB) are hypersensitive to elevated afterload. BACKGROUND: Epidemiological data suggest that LBBB can provoke heart failure in patients with hypertension. METHODS: In 11 asymptomatic patients with isolated LBBB and 11 age-matched control subjects, left ventricular ejection fraction (LVEF) and global longitudinal strain (GLS) were measured by echocardiography. Systolic arterial pressure was increased by combining pneumatic extremity constrictors and handgrip exercise. To obtain more insight into mechanisms of afterload response, 8 anesthetized dogs with left ventricular (LV) micromanometer and dimension crystals were studied during acutely induced LBBB and aortic constriction. Regional myocardial work was assessed by LV pressure-dimension analysis. RESULTS: Consistent with normal afterload dependency, elevation of systolic arterial pressure by 38 ± 12 mm Hg moderately reduced LVEF from 60 ± 4% to 54 ± 6% (p < 0.01) in control subjects. In LBBB patients, however, a similar blood pressure increase caused substantially larger reduction in LVEF (p < 0.01), from 56 ± 6% to 42 ± 7% (p < 0.01). There were similar findings for GLS. In the dog model, aortic constriction abolished septal shortening (p < 0.02), and septal work decreased to negative values (p < 0.01). Therefore, during elevated systolic pressure, the septum made no contribution to global LV work, as indicated by net negative work, and instead absorbed energy from work done by the LV lateral wall. CONCLUSIONS: Moderate elevation of arterial pressure caused marked reductions in LVEF and GLS in patients with LBBB. This reflects a cardiodepressive effect of elevated afterload in the dyssynchronous ventricle and was attributed to loss of septal function.

18.
J Appl Physiol (1985) ; 125(5): 1482-1489, 2018 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-30188795

RESUMO

Atrial switch operation in patients with transposition of the great arteries (TGA) leads to leftward shift and changes the geometry of the interventricular septum. By including the implications of regional work and septal curvature, this study investigates if changes in septal function and geometry contribute to reduced function of the systemic right ventricle (RV) in adult TGA patients. Regional myocardial work estimation has been possible by applying a recently developed method for noninvasive work calculation based on echocardiography. In 14 TGA patients (32 ± 6 yr, means ± SD) and 14 healthy controls, systemic ventricular systolic strains were measured by speckle tracking echocardiography and regional work was calculated by pressure-strain analysis. In TGA patients, septal longitudinal strain was reduced to -14 ± 2 vs. -20 ± 2% in controls ( P < 0.01) and septal work was reduced from 2,046 ± 318 to 1,146 ± 260 mmHg·% ( P < 0.01). Septal circumferential strain measured in a subgroup of patients was reduced to -11 ± 3 vs. -27 ± 3% in controls ( P < 0.01), and a reduction of septal work (540 ± 273 vs. 2,663 ± 459 mmHg·%) was seen ( P < 0.01). These reductions were in part attributed to elevated afterload due to increased radius of curvature of the leftward shifted septum. To conclude, in this mechanistic study we demonstrate that septal dysfunction contributes to failure of the systemic RV after atrial switch in TGA patients. This is potentially a long-term response to increased afterload due to a flatter septum and suggests that medical therapy that counteracts septal flattening may improve function of the systemic RV. NEW & NOTEWORTHY We have demonstrated that transposition of the great arteries patients with systemic right ventricles (RVs) have reduced function of the interventricular septum (IVS). Since the IVS is constructed to eject into the systemic circulation, it may seem unexpected that it does not maintain function when being part of the systemic RV. By applying the principles of regional work, wall tension, and geometry, we have identified unfavorable working conditions for the IVS when the RV adapts to systemic pressures.


Assuntos
Transposição das Grandes Artérias/efeitos adversos , Septos Cardíacos/fisiopatologia , Transposição dos Grandes Vasos/fisiopatologia , Disfunção Ventricular Direita/etiologia , Adulto , Fenômenos Biomecânicos , Estudos de Casos e Controles , Feminino , Humanos , Masculino , Transposição dos Grandes Vasos/cirurgia , Disfunção Ventricular Direita/fisiopatologia , Função Ventricular Esquerda , Adulto Jovem
19.
J Am Soc Echocardiogr ; 31(7): 799-806, 2018 07.
Artigo em Inglês | MEDLINE | ID: mdl-29580694

RESUMO

BACKGROUND: There is a paucity of data on the utility of right atrial pressure (RAP) for estimating pulmonary capillary wedge pressure (PCWP) in patients with normal ejection fraction (EF), including patients with heart failure with preserved EF. METHODS: Mean RAP was compared with PCWP in 129 patients (mean age, 61 ± 11 years; 45% men) with exertional dyspnea enrolled in a multicenter study. Measurements included left ventricular volumes, EF, and mitral inflow velocities. RESULTS: Mean PCWP was 14 ± 7 mm Hg, and mean RAP was 8 ± 5 mm Hg. A significant relation was present between mean RAP and mean PCWP (r2 = 0.5, P < .001). RAP > 8 mm Hg had 76% sensitivity and 86% specificity in detecting mean PCWP > 12 mm Hg. In 101 patients with inconclusive mitral filling pattern (defined according to American Society of Echocardiography/European Association of Cardiovascular Imaging 2016 diastolic function recommendations), RAP by catheterization had sensitivity of 73% and specificity of 91%. In a subset of 59 patients with echocardiographic assessment of mean RAP, RAP by echocardiography had sensitivity of 76% and specificity of 89%. CONCLUSIONS: Mean RAP provides useful information about mean PCWP in many patients with normal left ventricular EF. There is good sensitivity and excellent specificity when combining invasive or noninvasive RAP and mitral velocities to determine if PCWP is elevated.


Assuntos
Pressão Atrial/fisiologia , Cateterismo Cardíaco/métodos , Ecocardiografia/métodos , Insuficiência Cardíaca/diagnóstico , Pressão Propulsora Pulmonar/fisiologia , Volume Sistólico/fisiologia , Fatores Etários , Idoso , Estudos de Coortes , Feminino , Insuficiência Cardíaca/terapia , Humanos , Masculino , Pessoa de Meia-Idade , Prognóstico , Estudos Prospectivos , Reprodutibilidade dos Testes , Medição de Risco , Fatores Sexuais , Função Ventricular Esquerda/fisiologia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA