Publications by authors named "Knut Matre"

Article Synopsis
  • Global left ventricular (LV) function declines as aortic valve stenosis (AS) worsens, but the specific deformation changes from base to apex had not been studied until now.
  • A cross-sectional study involving 85 AS patients used 3D echocardiography to assess global LV function and deformation patterns by categorizing patients into mild, moderate, and severe AS groups.
  • Results showed that as AS severity increased, global and regional myocardial function decreased, particularly in males and those with higher body mass index, linking LV mechanics to AS severity and cardiovascular risk factors.*
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Aims: Patients with severe obesity are predisposed to left ventricular (LV) hypertrophy, increased myocardial oxygen demand, and impaired myocardial mechanics. Bariatric surgery leads to rapid weight loss and improves cardiovascular risk profile. The present prospective study assesses whether LV wall mechanics improve 1 year after bariatric surgery.

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Background: Aortic valve sclerosis (AVS), mitral valve sclerosis (MVS), remodeling of major arteries, and increased pericardial fat are associated with subclinical atherosclerosis. We assessed these markers of atherosclerosis in severely obese patients before and 1 year after bariatric surgery. Methods: Eighty-seven severely obese patients (43 ± 10 years, preoperative body mass index [BMI] 41.

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Speckle tracking echocardiography is a promising method for assessment of myocardial function in fetal and neonatal hearts, but further studies are necessary to validate and optimize the settings for use in fetal cardiology. Previous studies have shown that the definition of the region of interest (ROI) affects strain values in adults. The aim of this study was to investigate how different widths of ROI influences measurements of four-chamber longitudinal systolic strain in fetuses late in pregnancy.

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The aims of this study was to assess the effect of using a four chamber versus a three plane model on speckle tracking derived global longitudinal strain, the effects of drift compensation, the effect of assessing strain in different layers and finally the interplay between these aspects for the assessment of strain in neonates. Speckle tracking derived longitudinal strain was obtained from 22 healthy neonates. ANOVA, Bland-Altman analyses, coefficients of variation and assessment of intraclass correlation coefficients were conducted to assess the effect of the abovementioned aspects as well as assess both inter-observer and intra-observer variability.

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Clinical application of strain in neonates requires an understanding of which image acquisition and processing parameters affect strain values. Previous studies have examined frame rate, transmitting frequency, and vendor heterogeneity. However, there is a lack of human studies on how user-regulated spatial and temporal smoothing affect strain values in 36 neonates.

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Background And Aims: Increased myocardial oxygen (O) demand carries higher cardiovascular risk in hypertension. We hypothesized that myocardial O demand is increased in severe obesity and linked to early left ventricular (LV) dysfunction.

Methods And Results: Baseline data from 106 severely obese subjects referred for gastric bypass surgery (42 ± 11 years, 74% women, body mass index [BMI] 41.

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Introduction: Sex-difference in types of cardiac organ damage has been reported in subjects with increased body mass index (BMI). However less is known about sex-differences in left ventricular (LV) myocardial function assessed by global longitudinal strain (GLS) in these subjects.

Methods: 493 subjects (mean age 47 ± 9 years, 61% women) with BMI > 27.

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Article Synopsis
  • The study investigates the relationship between first-phase ejection fraction (EF1) and factors like myocardial contractility and arterial load in patients with aortic stenosis (AS).
  • Data from 114 patients with varying severities of AS were analyzed, focusing on how these factors influence EF1 measured during peak aortic jet velocity.
  • Results indicated that lower EF1 correlates with reduced myocardial contractility and increased arterial load, regardless of AS severity, suggesting these could be important markers for assessing cardiac function in AS patients.
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Reference values for left ventricular systolic strain in healthy neonates are necessary for clinical application of strain. The objectives of this systematic review were to identify echocardiographic studies that presented left ventricular strain values in healthy neonates, perform a meta-analysis for speckle tracking-derived global longitudinal strain, and identify areas that require further investigation. A structured search was applied to MEDLINE, Embase, and Cochrane Central Register of Clinical Trials in search of echocardiographic studies that presented left ventricular strain in healthy neonates.

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Traditional two-dimensional (2D) ultrasound speckle tracking echocardiography (STE) studies have shown a wide range of twist values, also for normal hearts, which is due to the limitations of short-axis 2D ultrasound. The same limitations do not apply to three-dimensional (3D) ultrasound, and several studies have shown 3D ultrasound to be superior to 2D ultrasound, which is unreliable for measuring twist. The aim of this study was to develop a left ventricular twisting phantom and to evaluate the accuracy of 3D STE twist measurements using different acquisition methods and volume rates (VR).

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Objective: Subclinical left ventricular (LV) myocardial dysfunction is associated with an increased risk of cardiovascular disease (CVD), but it is not known whether subclinical LV myocardial dysfunction is present in patients with ankylosing spondylitis (AS) independent of CVD risk factors.

Methods: Conventional and speckle tracking echocardiography were performed in 106 patients with AS (mean ± SD age 48 ± 12 years; 59% men) and 106 matched controls (mean ± SD age 51 ± 12 years; 59% men). LV systolic myocardial function was assessed by peak systolic global longitudinal strain (GLS).

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Background: Hypertension is highly prevalent in ischemic stroke patients, but less is known about its impact on subclinical left ventricular (LV) dysfunction in such patients.

Methods: Conventional and speckle tracking echocardiography was performed in 276 young (15-44 years) and middle-aged (45-60 years) ischemic stroke patients (mean age 50 ± 9 years, 66% men). Hypertension was defined as a history of hypertension, use of antihypertensive medications, persistently elevated blood pressure (BP) during hospitalization or elevated clinic BP (≥140/90 mmHg) and ambulatory BP (≥130/80 mmHg) at follow-up visits.

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Introduction: This experimental study compares myocardial function after prolonged arrest by St. Thomas' Hospital polarizing cardioplegic solution (esmolol, adenosine, Mg) with depolarizing (hyperkalaemic) St. Thomas' Hospital No 2, both administered as cold oxygenated blood cardioplegia.

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Objectives: This study investigated whether the novel St. Thomas' Hospital polarizing cardioplegic solution (STH-POL) with esmolol/adenosine/magnesium offers improved myocardial protection by reducing demands for high-energy phosphates during cardiac arrest compared to the depolarizing St. Thomas' Hospital cardioplegic solution No 2 (STH-2).

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Article Synopsis
  • The study aimed to assess if adding carvedilol, a heart medication with antioxidant properties, to oxygenated blood cardioplegia could enhance heart function post-surgery in pigs.
  • In a controlled experiment involving twenty anesthetized pigs, researchers found that carvedilol improved several metrics of heart function, including left ventricular compliance and reduced oxidative stress, compared to the control group.
  • Key results indicated that after 100 minutes of cardiac arrest and subsequent heart reperfusion, the carvedilol group exhibited better diastolic function and lower levels of oxidative damage, suggesting potential benefits for cardiac protection.
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Objectives: Disease activity has emerged as a new, independent risk factor for cardiovascular disease in patients with rheumatoid arthritis (RA). We tested if disease activity in RA was associated with lower left ventricular (LV) systolic function independent of traditional cardiovascular risk factors.

Methods: Echocardiographic assessment was performed in 78 patients with RA having low, moderate or high disease activity (Simplified Disease Activity Index (SDAI) >3.

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The purpose of this study was to investigate the effect of frame rate and probe frequency on the accuracy of speckle tracking echocardiography-derived strain measurements in infants. An infant-sized left ventricle phantom with sonomicrometer crystals was made from polyvinyl alcohol. The examined stroke rates were 60, 120 and 180 strokes per min (SPM).

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Noninvasive measurements of myocardial strain and strain rate by speckle tracking echocardiography correlate to cardiac contractile state but also to load, which may weaken their value as indices of inotropy. In a porcine model, we investigated the influence of acute dynamic preload reductions on left ventricular strain and strain rate and their relation to the pressure-conductance catheter-derived preload recruitable stroke work (PRSW) and peak positive first derivative of left ventricular pressure (LV-dP/dtmax). Speckle tracking strain and strain rate in the longitudinal, circumferential, and radial directions were measured during acute dynamic reductions of end-diastolic volume during three different myocardial inotropic states.

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Objectives: Potassium-based depolarizing St Thomas' Hospital cardioplegic solution No 2 administered as intermittent, oxygenated blood is considered as a gold standard for myocardial protection during cardiac surgery. However, the alternative concept of polarizing arrest may have beneficial protective effects. We hypothesize that polarized arrest with esmolol/adenosine/magnesium (St Thomas' Hospital Polarizing cardioplegic solution) in cold, intermittent oxygenated blood offers comparable myocardial protection in a clinically relevant animal model.

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Background: Left ventricular (LV) radial tissue Doppler imaging (TDI) strain increases gradually from the subepicardial to the subendocardial layer in healthy individuals. A speckle tracking echocardiography study suggested this gradient to be reduced in parallel with increasing aortic stenosis (AS) severity.

Methods: We used TDI strain in 84 patients with AS (mean age 73 ± 10 years, 56% hypertensive) for superior assessment of layer strain.

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Article Synopsis
  • The study explored whether esmolol, a β-receptor blocker, improves heart function when added to standard cardioplegia in pigs.
  • After 3 hours of reperfusion, esmolol-treated pigs showed significantly better heart performance and increased cardiac index compared to the control group.
  • Overall, esmolol appears to help preserve heart function after surgery without affecting troponin-T levels, indicating no additional cardiac damage.
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Background: Experimental studies have demonstrated that insulin elicits cardioprotection in coronary occlusion-reperfusion models. We studied the effects of intracoronary insulin on regional cardiac function in a porcine model with reperfusion after a critical coronary artery stenosis.

Methods: In 20 anaesthetized pigs with an extracorporeal shunt from the brachiocephalic to the left anterior descending coronary artery, a fixed stenosis was applied, obtaining 50% reduction of shunt flow for 60 min.

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