1,720,986 research outputs found
The second law of thermodynamics and the heart
No full textThe second law of thermodynamics explains the phenomenon of irreversibility and the increasing entropic trend of nature. Similar to human-made machines, living structures are subjected to entropy generation, becoming 'worn' and 'damaged' from use. However, they have the possibility of eluding or deferring these processes. According to nonequilibrium thermodynamics, the heart could be considered as an open dissipative system, since it has the potential to offset the body's increasing entropic burden by using energy to export entropy to the surroundings. By organizing the tissues' molecules in order to perform external work as a result of its ability to provide oxygen and nutrients and remove waste products, the heart maintains the organization of the living structure and acts as an open dissipative system. However, the increase in tissues' randomness and disorder as a result of a number of disease states may be responsible for the intervening cardiac damage and entropy generation. This effect is known as the 'Dorian Gray effect' of the heart. Technical advances, including MRI and 3D echocardiography, may provide a means to improve the understanding of thermodynamic aspects of cardiovascular physiology and heart diseas
The potential value of integrated natriuretic peptide and echo-guided heart failure management
Full text linkThere is increasing interest in guiding Heart Failure (HF) therapy with Brain Natriuretic Peptide (BNP) or N-terminal prohormone of Brain Natriuretic Peptide (NT-proBNP), with the goal of lowering concentrations of these markers (and maintaining their suppression) as part of the therapeutic approach in HF. However, recent European Society of Cardiology (ESC) and American Heart Association/American College of Cardiology (AHA/ACC) guidelines did not recommend biomarker-guided therapy in the management of HF patients. This has likely to do with the conceptual, methodological, and practical limitations of the Natriuretic Peptides (NP)-based approach, including biological variability, slow time-course, poor specificity, cost and venipuncture, as well as to the lack of conclusive scientific evidence after 15 years of intensive scientific work and industry investment in the field. An increase in NP can be associated with accumulation of extra-vascular lung water, which is a sign of impending acute heart failure. If this is the case, an higher dose of loop diuretics will improve symptoms. However, if no lung congestion is present, diuretics will show no benefit and even harm. It is only a combined clinical, bio-humoral (for instance with evaluation of renal function) and echocardiographic assessment which may unmask the pathophysiological (and possibly therapeutic) heterogeneity underlying the same clinical and NP picture. Increase in B-lines will trigger increase of loop diuretics (or dialysis); the marked increase in mitral insufficiency (at baseline or during exercise) will lead to increase in vasodilators and to consider mitral valve repair; the presence of substantial inotropic reserve during stress will give a substantially higher chance of benefit to beta-blocker or Cardiac Resynchronization Therapy (CRT). To each patient its own therapy, not with a "blind date" with symptoms and NP and carpet bombing with drugs, but with an open-eye targeted approach on the mechanism predominant in that individual patient. A monocular, specialistic, unidimensional approach to HF can miss its pathogenetic and clinical complexity, which only can be overcome with an integrated, versatile and tailored approach
Left atrial strain: a new parameter for assessment of left ventricular filling pressure
No full textIn order to obtain accurate diagnosis, treatment and prognostication in many cardiac conditions, there is a need for assessment of left ventricular (LV) filling pressure. While systole depends on ejection function of LV, diastole and its disturbances influence filling function and pressures. The commonest condition that represents the latter is heart failure with preserved ejection fraction in which LV ejection is maintained, but diastole is disturbed and hence filling pressures are raised. Significant diastolic dysfunction results in raised LV end-diastolic pressure, mean left atrial (LA) pressure and pulmonary capillary wedge pressure, all referred to as LV filling pressures. Left and right heart catheterization has traditionally been used as the gold standard investigation for assessing these pressures. More recently, Doppler echocardiography has taken over such application because of its noninvasive nature and for being patient friendly. A number of indices are used to achieve accurate assessment of filling pressures including: LV pulsed-wave filling velocities (E/A ratio, E wave deceleration time), pulmonary venous flow (S wave and D wave), tissue Doppler imaging (E′ wave and E/E′ ratio) and LA volume index. LA longitudinal strain derived from speckle tracking echocardiography (STE) is also sensitive in estimating intracavitary pressures. It is angle-independent, thus overcomes Doppler limitations and provides highly reproducible measures of LA deformation. This review examines the application of various Doppler echocardiographic techniques in assessing LV filling pressures, in particular the emerging role of STE in assessing LA pressures in various conditions, e.g., HF, arterial hypertension and atrial fibrillation
Combining echo-derived haemodynamic phenotypes and myocardial strain for risk stratification of chronic heart failure with reduced ejection fraction
No full textEchocardiography has shown to categorize heart failure (HF) patients according to haemodynamic profiles. Whether left ventricular (LV) global longitudinal strain (LV-GLS) could integrate echo-derived haemodynamic profiles to risk stratify chronic HF patients is still unknown
[The right ventricle: role of Doppler echocardiography in clinical practice]
No full textTo date, right ventricular function can be clinically assessed by Doppler echocardiography. Monodimensional and two-dimensional echocardiography provide information about right ventricular dimensions, wall thickness and tricuspid annular plane systolic excursion, which is an accurate estimate of longitudinal systolic function. Additional insights into right ventricular systolic function are given by Doppler interrogation of right ventricular outflow, measuring the duration of systolic time intervals. The Doppler recordings of the tricuspid inflow and hepatic venous flow allow the assessment of right ventricular diastolic properties. Also the new ultrasound technologies are clinically useful. The myocardial velocities and time intervals, detectable by pulsed tissue Doppler at the level of the tricuspid annulus, are markers of systolic and diastolic longitudinal motion of the right ventricle. The off-line strain rate imaging permits quantification of right ventricular myocardial contractility and may be particularly useful for the assessment of congenital cardiomyopathies. The right ventricular filling pressure and pulmonary arterial pressure may be derived by the combined analysis of the grade of tricuspid regurgitation and the respiratory reactivity of the inferior vena cava. The systolic time intervals, measured at the level of the right ventricular outflow, represent estimates of changes in pulmonary vascular resistance. The prognostic value of Doppler echocardiographic measurements of right ventricular function is demonstrated in various pathologies. This evaluation also provides additional value for the risk stratification of patients with chronic heart failure
Acute pericarditis as a major clinical manifestation of long COVID-19 syndrome
No full textBACKGROUND: The long COVID-19 syndrome has been recently described and some reports have suggested that acute pericarditis represents important manifestation of long COVID-19 syndrome. The aim of this study was to identify the prevalence and clinical characteristics of patients with long COVID-19, presenting with acute pericarditis. METHODS: We retrospectively included 180 patients (median age 47 years, 62% female) previously diagnosed with COVID-19, exhibiting persistence or new-onset symptoms ≥12 weeks from a negative naso-pharyngeal SARS CoV2 swamp test. The original diagnosis of COVID-19 infection was determined by a positive swab. All patients had undergone a thorough physical examination. Patients with suspected heart involvement were referred to a complete cardiovascular evaluation. Echocardiography was performed based on clinical need and diagnosis of acute pericarditis was achieved according to current guidelines. RESULTS: Among the study population, shortness of breath/fatigue was reported in 52%, chest pain/discomfort in 34% and heart palpitations/arrhythmias in 37%. Diagnosis of acute pericarditis was made in 39 patients (22%). Mild-to-moderate pericardial effusion was reported in 12, while thickened and bright pericardial layers with small effusions (< 5 mm) with or without comet tails arising from the pericardium (pericardial B-lines) in 27. Heart palpitations/arrhythmias (OR:3.748, p = 0.0030), and autoimmune disease and allergic disorders (OR:4.147, p = 0.0073) were independently related to the diagnosis of acute pericarditis, with a borderline contribution of less likelihood of hospitalization during COVID-19 (OR: 0.100, p = 0.0512). CONCLUSION: Our findings suggest a high prevalence of acute pericarditis in patients with long COVID-19 syndrome. Autoimmune and allergic disorders, and palpitations/arrhythmias were frequently associated with pericardial disease
Combining echo and natriuretic peptides to guide heart failure care in the outpatient setting: A position paper
No full textBACKGROUND: Chronic heart failure (HF) is a relevant and growing public health problem. Although the prognosis has recently improved, it remains a lethal disease, with a mortality that equals or exceeds that of many malignancies. Furthermore, chronic HF is costly, representing a large and growing drain on healthcare resources.
METHODS: This narrative review is based on the material searched for and obtained via PubMed up to May 2017. The search terms we used were: "heart failure, echocardiography, natriuretic peptides" in combination with "treatment, biomarkers, guidelines".
RESULTS: Particularly, hospitalization contributes to the greatest proportion of expenditure. Recent studies have supported the value of natriuretic peptides (NPs) and Doppler echocardiographic biomarkers of increased left ventricular (LV) filling pressures or pulmonary congestion as tools to scrutinize patients with impending clinically overt HF. Therefore, combination of pulsed-wave tissue and blood-flow Doppler with NPs appears valuable in guiding HF management in the outpatient setting. In as much as both the echo and the plasma levels of NPs may reflect the presence of fluid overload and elevations of LV filling pressures, integrating NP and echocardiographic biomarkers with clinical findings may help the cardiologist to identify high-risk patients, i.e. to recognize whether a patient is stable or the condition is likely to evolve into decompensated HF, to optimize treatment, to improve the prognosis and to reduce re-hospitalization.
CONCLUSION: we discussed the rationale and the clinical significance of combining follow-up echo and NP assessment to guide management of ambulatory patients with chronic HF
Prognostic value of cardiac power output to left ventricular mass in patients with left ventricular dysfunction and dobutamine stress echo negative by wall motion criteria
No full textCardiac power output to left ventricular mass (power/mass) is an index of myocardial efficiency reflecting the rate at which cardiac work is delivered with respect to the potential energy stored in the left ventricular mass. In the present study, we sought to investigate the capability of power/mass assessed at peak of dobutamine stress echocardiography to predict mortality in patients with ischaemic cardiomyopathy and no inducible ischaemia
Association of left ventricular longitudinal and circumferential systolic dysfunction with diastolic function in hypertension: a nonlinear analysis focused on the interplay with left ventricular geometry
No full textBackground The relationships of left ventricular (LV) longitudinal and circumferential systolic dysfunction with diastolic performance in hypertensive patients have never been compared. Methods and Results In 532 asymptomatic hypertensive patients, circumferential function was assessed with the use of midwall fractional shortening (mFS) and stress-corrected mFS (SCmFS), whereas longitudinal function was assessed with the use of left atrioventricular plane displacement (AVPD) and systolic mitral annulus velocity (s′). Early diastolic annular velocity (e′) and the E/e′ ratio were measured. Global longitudinal and circumferential strain were determined in a subset of 210 patients. e′ was linearly related to all systolic indexes (AVPD: R = 0.40; s′: R = 0.39; mFS: R = 0.16; SCmFS: R = 0.17; all P <.0001), but the correlations were stronger with longitudinal indexes than with circumferential ones (P <.0001). E/e′ was nonlinearly related to AVPD (R = -0.49; P <.0001) and s′ (R = -0.34; P <.0001) and showed no relationship with mFS and SCmFS. Longitudinal indexes were superior to circumferential ones in predicting e′ <8 cm/s, E/e′ <8, and E/e′ ≥13. The effect of LV geometry on LV diastolic function was evident among patients with preserved systolic longitudinal function, but was blunted among patients with impaired longitudinal function. In multivariable analyses, only longitudinal indexes remained associated with e′ and E/e′. Analyses using strains provided similar results. Conclusions In asymptomatic hypertensive subjects, LV diastolic performance is independently associated with longitudinal systolic dysfunction, but not with circumferential systolic dysfunction. Subtle longitudinal systolic impairment plays a role in mediating the effect of LV geometry on diastolic performance. These findings may support the need of critically revising the concept of isolated diastolic dysfunction in these patients
Optimizing Management of Heart Failure by Using Echo and Natriuretic Peptides in the Outpatient Unit
No full textChronic heart failure (HF) is an important public health problem and is associated with high morbidity, high mortality, and considerable healthcare costs. More than 90% of hospitalizations due to worsening HF result from elevations of left ventricular (LV) filling pressures and fluid overload, which are often accompanied by the increased synthesis and secretion of natriuretic peptides (NPs). Furthermore, persistently abnormal LV filling pressures and a rise in NP circulating levels are well known indicators of poor prognosis. Frequent office visits with the resulting evaluation and management are most often needed. The growing pressure from hospital readmissions in HF patients is shifting the focus of interest from traditionally symptom-guided care to a more specific patient-centered follow-up care based on clinical findings, BNP and echo. Recent studies supported the value of serial NP measurements and Doppler echocardiographic biomarkers of elevated LV filling pressures as tools to scrutinize patients with impending clinically overt HF. Therefore, combination of echo and pulsed-wave blood-flow and tissue Doppler with NPs appears valuable in guiding ambulatory HF management, since they are potentially useful to distinguish stable patients from those at high risk of decompensation.</p
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