Publications by authors named "Maciej Marciniak"

23 Publications

  • Page 1 of 1

Association of Systolic Blood Pressure Elevation With Disproportionate Left Ventricular Remodeling in Very Preterm-Born Young Adults: The Preterm Heart and Elevated Blood Pressure.

JAMA Cardiol 2021 May 12. Epub 2021 May 12.

Oxford Cardiovascular Clinical Research Facility, Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, England.

Importance: Preterm-born individuals have higher blood pressure with an increased risk of hypertension by young adulthood, as well as potentially adverse cardiac remodeling even when normotensive. To what extent blood pressure elevation affects left ventricular (LV) structure and function in adults born preterm is currently unknown.

Objective: To investigate whether changes observed in LV structure and function in preterm-born adults make them more susceptible to cardiac remodeling in association with blood pressure elevation.

Design, Setting, And Participants: This cross-sectional cohort study, conducted at the Oxford Cardiovascular Clinical Research Facility and Oxford Centre for Clinical Magnetic Resonance Research, included 468 adults aged 18 to 40 years. Of these, 200 were born preterm (<37 weeks' gestation) and 268 were born at term (≥37 weeks' gestation). Cardiac magnetic resonance imaging was used to characterize LV structure and function, with clinical blood pressure readings measured to assess hypertension status. Demographic and anthropometric data, as well as birth history and family medical history information, were collected. Data were analyzed between January 2012 and February 2021.

Main Outcomes And Measures: Cardiac magnetic resonance measures of LV structure and function in response to systolic blood pressure elevation.

Results: The cohort was primarily White (>95%) with a balanced sex distribution (51.5% women and 48.5% men). Preterm-born adults with and without hypertension had higher LV mass index, reduced LV function, and smaller LV volumes compared with term-born individuals both with and without hypertension. In regression analyses of systolic blood pressure with LV mass index and LV mass to end-diastolic volume ratio, there was a leftward shift in the slopes in preterm-born compared with term-born adults. Compared with term-born adults, there was a 2.5-fold greater LV mass index per 1-mm Hg elevation in systolic blood pressure in very and extremely preterm-born adults (<32 weeks' gestation) (0.394 g/m2 vs 0.157 g/m2 per 1 mm Hg; P < .001) and a 1.6-fold greater LV mass index per 1-mm Hg elevation in systolic blood pressure in moderately preterm-born adults (32 to 36 weeks' gestation) (0.250 g/m2 vs 0.157 g/m2 per 1 mm Hg; P < .001). The LV mass to end-diastolic volume ratio per 1-mm Hg elevation in systolic blood pressure in the very and extremely preterm-born adults was 3.4-fold greater compared with those born moderately preterm (3.56 × 10-3 vs 1.04 × 10-3 g/mL per 1 mm Hg; P < .001) and 3.3-fold greater compared with those born at term (3.56 × 10-3 vs 1.08 × 10-3 g/mL per 1 mm Hg; P < .001).

Conclusions And Relevance: Preterm-born adults have a unique LV structure and function that worsens with systolic blood pressure elevation. Additional primary prevention strategies specifically targeting cardiovascular risk reduction in this population may be warranted.
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http://dx.doi.org/10.1001/jamacardio.2021.0961DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8117059PMC
May 2021

Linking statistical shape models and simulated function in the healthy adult human heart.

PLoS Comput Biol 2021 Apr 15;17(4):e1008851. Epub 2021 Apr 15.

Cardiac Electromechanics Research Group, Biomedical Engineering Department, King´s College London, London, United Kingdom.

Cardiac anatomy plays a crucial role in determining cardiac function. However, there is a poor understanding of how specific and localised anatomical changes affect different cardiac functional outputs. In this work, we test the hypothesis that in a statistical shape model (SSM), the modes that are most relevant for describing anatomy are also most important for determining the output of cardiac electromechanics simulations. We made patient-specific four-chamber heart meshes (n = 20) from cardiac CT images in asymptomatic subjects and created a SSM from 19 cases. Nine modes captured 90% of the anatomical variation in the SSM. Functional simulation outputs correlated best with modes 2, 3 and 9 on average (R = 0.49 ± 0.17, 0.37 ± 0.23 and 0.34 ± 0.17 respectively). We performed a global sensitivity analysis to identify the different modes responsible for different simulated electrical and mechanical measures of cardiac function. Modes 2 and 9 were the most important for determining simulated left ventricular mechanics and pressure-derived phenotypes. Mode 2 explained 28.56 ± 16.48% and 25.5 ± 20.85, and mode 9 explained 12.1 ± 8.74% and 13.54 ± 16.91% of the variances of mechanics and pressure-derived phenotypes, respectively. Electrophysiological biomarkers were explained by the interaction of 3 ± 1 modes. In the healthy adult human heart, shape modes that explain large portions of anatomical variance do not explain equivalent levels of electromechanical functional variation. As a result, in cardiac models, representing patient anatomy using a limited number of modes of anatomical variation can cause a loss in accuracy of simulated electromechanical function.
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http://dx.doi.org/10.1371/journal.pcbi.1008851DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8049237PMC
April 2021

Septal curvature as a robust and reproducible marker for basal septal hypertrophy.

J Hypertens 2021 Jul;39(7):1421-1428

School of Biomedical Engineering and Imaging Sciences, Kings College London, London, UK.

Background: Basal septal hypertrophy (BSH) is an asymmetric, localized thickening of the upper interventricular septum and constitutes a marker of an early remodelling in patients with hypertension. This morphological trait has been extensively researched because of its prevalence in hypertension, yet its clinical and prognostic value for individual patients remains undetermined. One of the reasons is the lack of a reliable and reproducible metric to quantify the presence and the extent of BSH. This article proposes the use of the curvature of the left ventricular endocardium as a robust feature for BSH characterization, and as an objective criterion to quantify current subjective 'visual assessment' of the presence of sigmoidal septum. The proposed marker, called average septal curvature, is defined as the inverse of the radius adjacent to each point of the endocardial contour along the basal and mid inferoseptal segments of the left ventricle.

Method: Robustness and reproducibility were assessed on a cohort of 220 patients, including 161 hypertensive patients (32 with BSH) and 59 healthy controls.

Results: The results show that compared with the conventionally used wall thickness metrics, the new marker is more reproducible (relative standard deviation of errors of 7 vs. 13%, and 8 vs. 38% for intra-observer and inter-observer variability, respectively) and better correlates to the functional parameters related to BSH, with main difference (absolute rank correlation 0.417 vs. 0.341) in local deformation changes assessed by longitudinal strain.

Conclusion: Average septal curvature is a more precisely defined and reproducible metric than thickness ratios, it can be fully automated, and better infers the functional remodelling related to hypertension.
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http://dx.doi.org/10.1097/HJH.0000000000002813DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8183485PMC
July 2021

Generating Synthetic Labeled Data from Existing Anatomical Models: An Example with Echocardiography Segmentation.

IEEE Trans Med Imaging 2021 Jan 14;PP. Epub 2021 Jan 14.

Deep learning can bring time savings and increased reproducibility to medical image analysis. However, acquiring training data is challenging due to the time-intensive nature of labeling and high inter-observer variability in annotations. Rather than labeling images, in this work we propose an alternative pipeline where images are generated from existing high-quality annotations using generative adversarial networks (GANs). Annotations are derived automatically from previously built anatomical models and are transformed into realistic synthetic ultrasound images with paired labels using a CycleGAN. We demonstrate the pipeline by generating synthetic 2D echocardiography images to compare with existing deep learning ultrasound segmentation datasets. A convolutional neural network is trained to segment the left ventricle and left atrium using only synthetic images. Networks trained with synthetic images were extensively tested on four different unseen datasets of real images with median Dice scores of 91, 90, 88, and 87 for left ventricle segmentation. These results match or are better than inter-observer results measured on real ultrasound datasets and are comparable to a network trained on a separate set of real images. Results demonstrate the images produced can effectively be used in place of real data for training. The proposed pipeline opens the door for automatic generation of training data for many tasks in medical imaging as the same process can be applied to other segmentation or landmark detection tasks in any modality. The source code and anatomical models are available to other researchers.
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http://dx.doi.org/10.1109/TMI.2021.3051806DOI Listing
January 2021

Distribution of myocardial work in arterial hypertension: insights from non-invasive left ventricular pressure-strain relations.

Int J Cardiovasc Imaging 2021 Jan 12;37(1):145-154. Epub 2020 Aug 12.

Institute of Biomedical Research August Pi Sunyer (IDIBAPS), Carrer del Rosselló, 149, 08036, Barcelona, Spain.

A index of non-invasive myocardial work (MWI) can account for pressure during the assessment of cardiac function, potentially separating the influence of loading conditions from the influence of the underlying tissue remodelling. The aim is to assess LV function accounted for loading and explore hypertensive MWI distribution by comparing healthy individuals to hypertensive patients without and with localized basal septal hypertrophy (BSH). An echocardiogram was performed in 170 hypertensive patients and 20 healthy individuals. BSH was defined by a basal-to-mid septal wall thickness ratio ≥ 1.4. LV speckle-tracking was performed, and the MWI calculated globally and regionally for the apical, mid and basal regions. An apex-to-base gradient, seen in regional strain values, was preserved in the distribution of myocardial work, with the apical region compensating for the impairment of the basal segments. This functional redistribution was further pronounced in patients with localized BSH. In these patients, segmental MWI analysis revealed underlying impairment of regional work unrelated to acute loading conditions. Non-invasive MWI analysis offers the possibility to compare LV function regardless of blood pressure at the time of observation. Changes in MWI distribution can be seen in hypertension unrelated to the load-dependency of strain. Accentuated functional changes affirm the role of BSH as an echocardiographic marker in hypertension.
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http://dx.doi.org/10.1007/s10554-020-01969-4DOI Listing
January 2021

Basal Ventricular Septal Hypertrophy in Systemic Hypertension.

Am J Cardiol 2020 05 8;125(9):1339-1346. Epub 2020 Feb 8.

Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain; Cardiovascular Institute, Hospital Clínic and Universitat de Barcelona, Barcelona, Spain; CIBERCV, Instituto de Salud Carlos III (CB16/11/00354), CERCA Programme/Generalitat de Catalunya, Madrid, Spain.

Basal septal hypertrophy (BSH) is commonly seen in patients with systemic hypertension and has been associated with increased afterload. The impact of localized hypertrophy on left ventricular (LV) and left atrial (LA) function is still unclear. Our aim is to investigate if BSH is a marker of a more pronounced impact of hypertension on cardiac function in the early stages of hypertensive heart disease. An echocardiogram was performed in 163 well-controlled hypertensive patients and 22 healthy individuals. BSH was defined by a basal-to-mid septal thickness ratio ≥1.4. LV dimensions and mass were evaluated. LV global and regional deformation was assessed by 2-dimensional (2D) speckle tracking echocardiography, and LV diastolic function by 2D and Doppler imaging. LA function was evaluated with phasic volume indices calculated from 2D and 3-dimensional volumes, as well as speckle tracking echocardiography. The population was 54% men, mean age 57 (53 to 60) years. BSH was seen in 20% (n = 32) of the hypertensive cohort. Patients with BSH showed decreased regional LV systolic deformation, impaired LV relaxation with a higher proportion of indeterminate LV diastolic function, and LA functional impairment defined by a reduction of reservoir strain and a change in LA functional dynamics. In conclusion, in well-controlled hypertension impairment of LV and LA function is present in patients with early LV remodeling and localized hypertrophy. BSH might be useful as an early marker of the burden of hypertensive heart disease.
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http://dx.doi.org/10.1016/j.amjcard.2020.01.045DOI Listing
May 2020

The 'Digital Twin' to enable the vision of precision cardiology.

Eur Heart J 2020 12;41(48):4556-4564

Department of Engineering Science, University of Oxford, Oxford, UK.

Providing therapies tailored to each patient is the vision of precision medicine, enabled by the increasing ability to capture extensive data about individual patients. In this position paper, we argue that the second enabling pillar towards this vision is the increasing power of computers and algorithms to learn, reason, and build the 'digital twin' of a patient. Computational models are boosting the capacity to draw diagnosis and prognosis, and future treatments will be tailored not only to current health status and data, but also to an accurate projection of the pathways to restore health by model predictions. The early steps of the digital twin in the area of cardiovascular medicine are reviewed in this article, together with a discussion of the challenges and opportunities ahead. We emphasize the synergies between mechanistic and statistical models in accelerating cardiovascular research and enabling the vision of precision medicine.
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http://dx.doi.org/10.1093/eurheartj/ehaa159DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7774470PMC
December 2020

Cardiac Arrest in Acute Myocardial Infarction: Concept of Circulatory Support With Mechanical Chest Compression and Impella to Facilitate Percutaneous Coronary Intervention.

Heart Lung Circ 2017 Aug 28;26(8):e37-e40. Epub 2017 Feb 28.

King's College London British Heart Foundation Centre of Excellence, The Rayne Institute, St. Thomas' Hospital, London, England.

Cardiogenic shock in the context of acute ST-elevation myocardial infarction (STEMI) remains a challenge to manage and results in significant mortality and morbidity, cardiac arrest in this setting even more so. The increase in myocardial oxygen demand and consumption with the use of inotropes is recognised as increasing mortality. Alternatives include the intra-aortic balloon pump (IABP), which has yet to be shown to improve outcomes, and extracorporeal membrane oxygenation (ECMO), which requires super-specialised techniques not widely available. We report a case of Anterior STEMI from a left main stem occlusion suffering with cardiac arrest on reaching the catheter laboratory table necessitating external mechanical compression with an Autopulse™. The patient remained in pulseless electrical activity (PEA) throughout, and was Autopulse dependent despite successful percutaneous coronary intervention (PCI). An Impella was inserted for additional mechanical support and facilitated successful weaning from cardiopulmonary resuscitation (CPR). Despite 105minutes without a spontaneous output, we describe the first documented case of simultaneous use of Impella with mechanical CPR with a successful outcome; demonstrating a potential technique of good mechanical haemodynamic support to aide early revascularisation that may have potential utility in the treatment of cardiogenic shock and arrest.
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http://dx.doi.org/10.1016/j.hlc.2017.01.012DOI Listing
August 2017

Thrombus aspiration in acute myocardial infarction: concepts, clinical trials, and current guidelines.

Coron Artery Dis 2016 May;27(3):233-43

aSt Thomas' Hospital bKing's College Hospital, London cEast Surrey Hospital, Redhill, Surrey, UK.

The pathogenesis that underlies acute myocardial infarction is complex and multifactorial. One of the most important components, however, is the role of thrombus formation following atherosclerotic plaque rupture, leading to sudden coronary occlusion and subsequent ischemia and infarction. Thrombus aspiration provides the opportunity of intracoronary clot extraction with the aim to improve coronary and myocardial perfusion, by reducing the risk of no-reflow secondary to distal embolization of thrombus. The utility of thrombus aspiration during primary percutaneous coronary intervention has been assessed in an increasing number of observational and randomized studies. This article reviews the contemporary data and provides insights into the validity of thrombus aspiration in the setting of acute myocardial infarction.
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http://dx.doi.org/10.1097/MCA.0000000000000335DOI Listing
May 2016

Patent foramen ovale: the current state of play.

Heart 2015 Dec 20;101(23):1916-25. Epub 2015 Oct 20.

Department of Cardiology, Guy's and St Thomas' NHS Foundation Trust, London, UK.

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http://dx.doi.org/10.1136/heartjnl-2015-307639DOI Listing
December 2015

Multimodality imaging of extensive caseating intramyocardial calcification secondary to lymphoma.

Circ Cardiovasc Imaging 2015 Apr;8(4)

From the Department of Cardiology (A.M., M.M., R.R.) and Cardiovascular Division, Division of Imaging Sciences and Biomedical Engineering, King's College London British Heart Foundation Centre of Excellence, National Institute of Health Research Biomedical Research Centre (A.C., S.C., V.R., R.R.), Guy's and St Thomas' NHS Foundation Trust, London, United Kingdom.

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http://dx.doi.org/10.1161/CIRCIMAGING.114.002750DOI Listing
April 2015

Prediction of postoperative left ventricular systolic function in patients with chronic mitral regurgitation undergoing valve surgery--the role of deformation imaging.

Eur J Cardiothorac Surg 2011 Nov 1;40(5):1131-7. Epub 2011 Apr 1.

Department of Cardiology and Cardiothoracic Surgery, St. George's Hospital, London, UK.

Objective: Preoperative left ventricular systolic function is an important prognostic factor in patients undergoing mitral valve surgery. Preoperative myocardial deformation may be impaired without reduction in conventional indices such as ejection fraction (EF). Strain rate (SR) imaging is very sensitive in detecting regional systolic abnormalities and might allow diagnosis of subclinical changes in systolic left ventricular (LV) function before surgery. We aimed to investigate the value of preoperative regional myocardial peak systolic SR as a predictor of postoperative LV systolic function in patients with severe mitral regurgitation (MR) undergoing surgery.

Methods: A total of 62 patients (age 52±12) with chronic severe MR, who underwent mitral valve repair, were studied. A standard echo examination, extended with tissue Doppler, was performed before and at 12 months after surgery. For the evaluation of longitudinal function, mid-ventricular segment shortening was analysed for the septum, LV lateral wall and anterior and inferior walls.

Results: Patients were divided into two groups based on postoperative EF: group 1 with EF(post-op)>50% and group 2 with EF(post-op)<50%. Group 1 had a significantly (p=0.004) higher preoperative SR (LV lateral wall: -1.97±0.26s(-1); septum: -1.74±0.31s(-1); anterior wall: -1.94±0.30s(-1), inferior wall: -1.93±0.29s(-1)) compared to group 2 (LV lateral wall: -0.98±0.23s(-1); septum: -0.98±0.26s(-1); anterior wall: -0.94±0.30s(-1), inferior wall: -1.00±0.24s(-1)). When SR was corrected for size, the SR/EDV index (EDV is end diastolic volume) also showed significant changes (p=0.0007) at baseline between the groups. For detecting subclinical changes in deformation of the LV lateral wall, a cut-off value of the SR/EDV index<0.006 had 89% sensitivity and 93% specificity; for the anterior wall, SR/EDV index<0.005 had 88% sensitivity and 94% specificity.

Conclusions: SR imaging (corrected for geometry) can detect abnormalities in LV function at subclinical levels in patients with severe mitral regurgitation.
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http://dx.doi.org/10.1016/j.ejcts.2011.02.049DOI Listing
November 2011

Effect of modest salt reduction on skin capillary rarefaction in white, black, and Asian individuals with mild hypertension.

Hypertension 2010 Aug 28;56(2):253-9. Epub 2010 Jun 28.

Wolfson Institute of Preventive Medicine, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK.

Microvascular rarefaction occurs in hypertension. We carried out a 12-week randomized double-blind crossover trial to determine the effect of a modest reduction in salt intake on capillary rarefaction in 71 whites, 69 blacks, and 29 Asians with untreated mildly raised blood pressure. Both basal and maximal (during venous congestion) skin capillary density were measured by capillaroscopy at the dorsum and the side of the fingers. In addition, we used orthogonal polarization spectral imaging to measure skin capillary density at the dorsum of the fingers and the hand web. With a reduction in salt intake from 9.7 to 6.5 g/day, there was an increase in capillary density (capillaries per millimeter squared) from 101+/-21 to 106+/-23 (basal) and 108+/-22 to 115+/-22 (maximal) at the dorsum, and 101+/-25 to 107+/-26 (basal) and 110+/-26 to 116+/-26 (maximal) at the side of the fingers (P<0.001 for all). Orthogonal polarization spectral imaging also showed a significant increase in capillary density both at the dorsum of the fingers and the web. Subgroup analysis showed that most of the changes were significant in all of the ethnic groups. Furthermore, there was a significant relationship between the change in 24-hour urinary sodium and the change in capillary density at the side of the fingers. These results demonstrate that a modest reduction in salt intake, as currently recommended, improves both functional and structural capillary rarefactions that occur in hypertension, and a larger reduction in salt intake would have a greater effect. The increase in capillary density may possibly carry additional beneficial effects on target organs.
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http://dx.doi.org/10.1161/HYPERTENSIONAHA.110.155747DOI Listing
August 2010

Effects of potassium chloride and potassium bicarbonate on endothelial function, cardiovascular risk factors, and bone turnover in mild hypertensives.

Hypertension 2010 Mar 18;55(3):681-8. Epub 2010 Jan 18.

Wolfson Institute of Preventive Medicine, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, Charterhouse Square, London EC1M 6BQ, UK.

To determine the effects of potassium supplementation on endothelial function, cardiovascular risk factors, and bone turnover and to compare potassium chloride with potassium bicarbonate, we carried out a 12-week randomized, double-blind, placebo-controlled crossover trial in 42 individuals with untreated mildly raised blood pressure. Urinary potassium was 77+/-16, 122+/-25, and 125+/-27 mmol/24 hours after 4 weeks on placebo, potassium chloride, and potassium bicarbonate, respectively. There were no significant differences in office blood pressure among the 3 treatment periods, and only 24-hour and daytime systolic blood pressures were slightly lower with potassium chloride. Compared with placebo, both potassium chloride and potassium bicarbonate significantly improved endothelial function as measured by brachial artery flow-mediated dilatation, increased arterial compliance as assessed by carotid-femoral pulse wave velocity, decreased left ventricular mass, and improved left ventricular diastolic function. There was no significant difference between the 2 potassium salts in these measurements. The study also showed that potassium chloride reduced 24-hour urinary albumin and albumin:creatinine ratio, and potassium bicarbonate decreased 24-hour urinary calcium, calcium:creatinine ratio, and plasma C-terminal cross-linking telopeptide of type 1 collagen significantly. These results demonstrated that an increase in potassium intake had beneficial effects on the cardiovascular system, and potassium bicarbonate may improve bone health. Importantly, these effects were found in individuals who already had a relatively low-salt and high-potassium intake.
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http://dx.doi.org/10.1161/HYPERTENSIONAHA.109.147488DOI Listing
March 2010

How to detect early left atrial remodelling and dysfunction in mild-to-moderate hypertension.

J Hypertens 2009 Oct;27(10):2086-93

Blood Pressure Unit, Department of Cardiac and Vascular Sciences, St. George's, University of London, Blackshaw Road, London SW17 0QT, UK.

Background And Objectives: Early changes in left atrial function in hypertension are difficult to assess quantitatively. Measuring atrial reversal flow into the pulmonary veins and regional left atrial deformation parameters assessed by Tissue Doppler-derived strain/rate (S/SR) imaging could provide quantitative assessment of left atrial deformation. We aimed to quantify changes in left atrial volume and deformation and pulmonary flow reversal (PVREVERS) in hypertension to detect subclinical left atrial dysfunction.

Design, Setting And Patients: In 74 hypertensive and 34 age-matched normotensive patients (mean age 49 +/- 1.4 vs. 44.2 +/- 2.1 years) echo studies were performed, including measurements of LAV during reservoir, conduit and pump phases and standard indices reflecting left ventricular filling. S/SR was measured in the lateral left atrial wall. Total deformation (STOTAL) and the contribution to early (SE-index) and late (SA-index) filling were calculated.

Results: Hypertensive patients had significantly impaired diastolic function and increased left atrial volume during all phases. Only LAVCONDUIT significantly correlated with both ventricular hypertrophy and parameters of diastolic function. Velocity time integral of PVREVERS correlated with blood pressure and LAVCONDUIT. In hypertensive patients STOTAL was significantly higher (54.9 +/- 2.6 vs. 45.5 +/- 2.7%, P < 0.03) and SE-index was lower (P < 0.0001). This was compensated for by an increased SA-index (P < 0.0001) and SR during atrial contraction (-4.9 +/- 0.2 vs. -2.9 +/- 0.3 1/s, P < 0.0001). SA-index correlated significantly with blood pressure (R = 0.4; P < 0.0001) and PVREVERS (R = 0.3; P < 0.001).

Conclusion: Changes in left atrial function due to hypertensive diastolic impairment are best reflected by LAVCONDUIT expansion. Hypertensive atrial dilatation is related to increase in PVREVERS. Left atrial S/SR offers a clinically valuable approach to detecting subclinical atrial dysfunction.
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http://dx.doi.org/10.1097/HJH.0b013e32832f4f3dDOI Listing
October 2009

Effect of modest salt reduction on blood pressure, urinary albumin, and pulse wave velocity in white, black, and Asian mild hypertensives.

Hypertension 2009 Sep 20;54(3):482-8. Epub 2009 Jul 20.

Blood Pressure Unit, Cardiac & Vascular Sciences, St. George's, University of London, Cranmer Terrace, London, UK.

A reduction in salt intake lowers blood pressure. However, most previous trials were in whites with few in blacks and Asians. Salt reduction may also reduce other cardiovascular risk factors (eg, urinary albumin excretion, arterial stiffness). However, few well-controlled trials have studied these effects. We carried out a randomized double-blind crossover trial of salt restriction with slow sodium or placebo, each for 6 weeks, in 71 whites, 69 blacks, and 29 Asians with untreated mildly raised blood pressure. From slow sodium to placebo, urinary sodium was reduced from 165+/-58 (+/-SD) to 110+/-49 mmol/24 hours (9.7 to 6.5 g/d salt). With this reduction in salt intake, there was a significant decrease in blood pressure from 146+/-13/91+/-8 to 141+/-12/88+/-9 mm Hg (P<0.001), urinary albumin from 10.2 (IQR: 6.8 to 18.9) to 9.1 (6.6 to 14.0) mg/24 hours (P<0.001), albumin/creatinine ratio from 0.81 (0.47 to 1.43) to 0.66 (0.44 to 1.22) mg/mmol (P<0.001), and carotid-femoral pulse wave velocity from 11.5+/-2.3 to 11.1+/-1.9 m/s (P<0.01). Subgroup analysis showed that the reductions in blood pressure and urinary albumin/creatinine ratio were significant in all groups, and the decrease in pulse wave velocity was significant in blacks only. These results demonstrate that a modest reduction in salt intake, approximately the amount of the current public health recommendations, causes significant falls in blood pressure in all 3 ethnic groups. Furthermore, it reduces urinary albumin and improves large artery compliance. Although both could be attributable to the falls in blood pressure, they may carry additional benefits on reducing cardiovascular disease above that obtained from the blood pressure falls alone.
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http://dx.doi.org/10.1161/HYPERTENSIONAHA.109.133223DOI Listing
September 2009

Toward understanding response to cardiac resynchronization therapy: left ventricular dyssynchrony is only one of multiple mechanisms.

Eur Heart J 2009 Apr 11;30(8):940-9. Epub 2008 Nov 11.

Department of Cardiology, St George's Hospital, Blackshaw Road, SW17 0QT London, UK.

Aim: To date, most published echocardiographic methods have assessed left ventricular (LV) dyssynchrony (DYS) alone as a predictor for response to cardiac resynchronization therapy (CRT). We hypothesized that the response is instead dictated by multiple correctable factors.

Methods And Results: A total of 161 patients (66 +/- 10 years, EF 24 +/- 6%, QRS > 120 ms) were investigated pre- and post-CRT (median of 6 months). Reduction in NYHA Class >/=1 or LV reverse remodelling (end-systolic volume reduction >/= 10%) defined response. Four different pathological mechanisms were identified. Group1: LVDYS characterized by a pre-ejection septal flash (SF) (87 patients, 54%). Elimination of SF (77 of 87 patients) resulted in reverse remodelling in 100%. Group 2: short-AV delay (21 patients, 13%) resolution (19 of 21 patients) resulted in reverse remodelling in 16 of 19. Group 3: long-AV delay (16 patients, 10%) resolution (14 of 16 patients) resulted in NYHA Class reduction >/=1 in 11 with reverse remodelling in five patients. Group 4: exaggerated LV-RV interaction (15 patients, 9%) reduced post-CRT. All responded clinically with fall in pulmonary artery pressure (P = 0.003) but did not volume respond. Group 5: patients with none of the above correctable mechanisms (22 patients, 14%). None responded to CRT.

Conclusion: CRT response is dictated by correction of multiple independent mechanisms of which LVDYS is only one. Long-axis DYS measurements alone failed to detect 40% of responders.
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http://dx.doi.org/10.1093/eurheartj/ehn481DOI Listing
April 2009

Myocardial deformation abnormalities in patients with aortic regurgitation: a strain rate imaging study.

Eur J Echocardiogr 2009 Jan 25;10(1):112-9. Epub 2008 Jun 25.

Department of Cardiology and Cardiothoracic Surgery, St. George's Hospital, Blackshaw Road, London SW17 0QT, UK.

Aims: Early left ventricular (LV) dysfunction in asymptomatic patients with severe aortic regurgitation (AR) may go undetected due to the lack of a sufficiently sensitive diagnostic tool. Ultrasonic strain/strain rate (S/SR) imaging should now provide such sensitivity in detecting early dysfunction in regional LV systolic deformation. The aim of this study was to understand and define the changes in LV regional systolic deformation based on S/SR imaging in patients with asymptomatic or minimally symptomatic AR.

Methods And Results: Eighty-one individuals were studied: 59 asymptomatic patients with isolated non-ischaemic AR who were divided into three sub-groups such as mild, moderate, and severe AR and 22 age-matched healthy subjects. All patients underwent standard echocardiographic examinations including a tissue Doppler imaging study. For LV radial deformation, the posterior wall (LVPW) was examined. To assess LV longitudinal deformation, S and SR data were acquired from the LV lateral wall and septum. Radial as well as longitudinal peak systolic SRs were significantly decreased in patients with both moderate AR (LVPW, P=0.0009; septum, P=0.03; LV lateral wall, P=0.0009) and severe AR (P<0.0001) compared with healthy subjects. Changes in regional LV deformation correlated inversely both with LV end-diastolic volume and with end-systolic volume.

Conclusions: Strain rate imaging is a sensitive tool in detecting the spectrum of changes in radial and longitudinal deformation in asymptomatic or minimally symptomatic patients with AR. The index where volume was corrected by deformation should form the basis for predicting subclinical LV dysfunction in patients with increasing LV dilatation.
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http://dx.doi.org/10.1093/ejechocard/jen185DOI Listing
January 2009

The quantification of dipyridamole induced changes in regional deformation in normal, stunned or infarcted myocardium as measured by strain and strain rate: an experimental study.

Int J Cardiovasc Imaging 2008 Apr 2;24(4):365-76. Epub 2007 Oct 2.

Department of Cardiology, KULeuven, Leuven, Belgium.

Unlabelled: Strain rate imaging (SRI) during dobutamine stress-echocardiography (DSE) has been shown to differentiate between ischemic substrates based on the segmental response. Dipyridamole stress echo (DIPSE) is currently used as an alternative to DSE in detecting coronary artery disease. The aim of this study was: (a) to determine the normal response in peak-systolic myocardial strain (S) and strain-rate (SR) during DIPSE and (b) to compare the S and SR responses of DSE and DIPSE in the same chronically ischemic/infarcted segments in the setting of single vessel disease.

Methods: The deformation response to DIPSE was studied in 7 normal pigs and in an additional 18 pigs, with a spectrum of ischemic substrates. S and SR data were extracted from a posterior wall "at risk" segment at baseline and during both DSE and DIPSE. The animals were divided into different ischemic substrate (stunning, non-transmural and transmural infarction), based on the DSE response as previously suggested.

Results: In normal myocardium, dipyridamole induced no changes in regional systolic deformation neither during nor after the infusion. Furthermore there was no detectable response in S and SR in segments with either a non-transmural or a transmural infarction. However, in myocardial segments with a DSE "stunning response", both end systolic S and peak-systolic SR tended to "normalize" at peak dipyridamole dose.

Conclusions: These results suggest that dipyridamole does not induce changes in regional deformation in normal or (partially) infarcted myocardium. Only in stunned myocardium (in the setting of single-vessel disease), dipyridamole tends to normalize deformation.
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http://dx.doi.org/10.1007/s10554-007-9269-xDOI Listing
April 2008

Regional left ventricular deformation and geometry analysis provides insights in myocardial remodelling in mild to moderate hypertension.

Eur J Echocardiogr 2008 Jul 2;9(4):501-8. Epub 2007 Oct 2.

Department of Cardiology, St George's Hospital, Blackshaw Road, London SW17 0QT, UK.

Aim: In the early stages of hypertension (HTN), when global left ventricular (LV) function is still unaffected, localized geometrical changes suggest changes in regional function. We investigated regional geometry and systolic deformation (using strain/strain rate (S/SR) imaging) in HTN.

Methods And Results: We studied 74 untreated mild to moderate HTNs and 34 matched normotensives (NTN). All had a standard echo including myocardial velocity data for regional radial and longitudinal deformation. Despite the absence of abnormalities in standard functional indices and LVH, non-uniform changes in regional geometry and deformation were observed. Besides a significant increase in wall thickness (WT) in all HTN segments, there was a gradual increase in WT from apex to base resulting in prominent basal septal hypertrophy. In HTN, regional longitudinal peak systolic SR (SSR) and end-systolic S (ESS) were significantly (P < 0.0001) reduced in the basal septum. In the lateral wall there was an increase in peak SSR and ESS (P < 0.05) basally. The basal septal ESS correlated both with mean arterial pressure and basal septal WT, with lower ESS for higher BP and thicker septum.

Conclusion: Regionally differing geometrical remodelling occurs early in HTN. Longitudinal ESS and peak SSR are sensitive markers of early changes occurring in HTN.
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http://dx.doi.org/10.1016/j.euje.2007.08.004DOI Listing
July 2008

Full or pressure limited reperfusion of an acute myocardial infarct results in a different wall thickness and deformation of the distal myocardium--implications for clinical reperfusion strategies.

Eur J Echocardiogr 2008 Jul 23;9(4):458-65. Epub 2007 Aug 23.

Department of Cardiology, K.U.Leuven, Herestraat 49, B-3000 Leuven, Belgium.

Aim: The study aim was to determine the sequence of changes in both wall thickness and function in 'at risk' myocardium (using M-mode and radial strain/strain-rate imaging) induced by reperfusion of an acute transmural infarction, and to relate these changes to the presence or absence of a pressure-limiting stenosis in the infarct related epicardial vessel.

Methods: Eighteen closed-chest pigs were randomized into two groups (each with nine animals). In Group I, 4 weeks prior to induction of an acute transmural infarct, a copper coated stent was implanted in the proximal circumflex artery (Cx) to create a coronary artery stenosis of between 30 and 95% lumen diameter. At 4 weeks, the stenotic Cx vessel was occluded for 90 min by inflation of a PTCA balloon placed proximal to the stenosis to produce an acute transmural infarction. In Group II (the control group), 90 min Cx occlusion was performed in a normal vessel. In both groups the resulting acute transmural infarction was reperfused after 90 min by removing the PTCA balloon. For both groups, cardiac ultrasound data, including strain/strain-rate imaging, were collected at all stages of the investigation for subsequent offline analysis.

Results: In both groups, acute reperfusion (TIMI flow 3 or 2), immediately increased infarct zone end-diastolic wall thickness due to the development of oedema. The acute increase in wall thickness was significantly higher in the non-stenotic animals as compared to the ones with a residual stenosis. Neither of the groups showed any tendency to normalize deformation (strain) during the reperfusion period.

Conclusion: In this experimental study, the measurement of end-diastolic wall thickness was a simple and non-invasive tool to monitor acute infarct reperfusion. It also provided information on the presence of a flow limiting stenosis in the infarct related artery after restoration of the flow. The deformation of the myocardium remained impaired during early reperfusion, whether reflow was at full pressure or low pressure due to a residual stenosis in the infarct related artery.
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http://dx.doi.org/10.1016/j.euje.2007.06.007DOI Listing
July 2008

Changes in systolic left ventricular function in isolated mitral regurgitation. A strain rate imaging study.

Eur Heart J 2007 Nov 25;28(21):2627-36. Epub 2007 May 25.

Department of Cardiology and Cardiothoracic Surgery, St George's Hospital, London, UK.

Aims: The aim of the present study is to understand the changes in left ventricular (LV) regional systolic deformation based on strain rate (SR) imaging in patients with isolated mitral regurgitation (MR). Progressive LV dilatation and irreversible myocardial damage as a result of chronic isolated MR are important causes of morbidity and mortality in patients following valve surgery. To date, there is no specific diagnostic method to detect subclinical changes in systolic function before irreversible dysfunction occurs.

Methods And Results: Seventy-seven individuals were studied: 54 asymptomatic patients (age 56 +/- 12) with isolated non-ischaemic MR divided into three groups: mild, moderate, and severe and 23 healthy subjects. All underwent a standard echo examination and a tissue Doppler study. A mathematical study was carried out to predict how SR should alter with increasing dimensions and due to irreversible myocardial damage. Radial as well as longitudinal peak systolic SR was significantly decreased in patients with severe MR compared to the other groups (LV posterior wall: P = 0.0006, septum: P = 0.0004, LV lateral wall: P = 0.0003). From both modelling and in our patients, deformation correlated inversely with LV end-diastolic diameter and end-systolic diameter (ESD). Deformation measurements (corrected for increased geometry) enabled the identification of patients classically referred to as at risk of irreversible myocardial damage (ESD > or = 4.5 cm).

Conclusion: In patients with a wide range of MR, deformation remains unchanged due to a balance of increased dimensions and increased stroke volume. Only when contractility is expected to change, deformation will significantly decrease. SR imaging indices, corrected for geometry, might potentially be useful in detecting subclinical deterioration in LV function in asymptomatic patients with severe MR.
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http://dx.doi.org/10.1093/eurheartj/ehm072DOI Listing
November 2007

The potential clinical role of ultrasonic strain and strain rate imaging in diagnosing acute rejection after heart transplantation.

Eur J Echocardiogr 2007 Jun 23;8(3):213-21. Epub 2006 May 23.

Department of Cardiology, University Hospital Gasthuisberg, Herestraat 49, B-3000 Leuven, Belgium.

Background: There has been a continued search for a more sensitive noninvasive technique for detecting sub-clinical acute rejection in heart transplant recipients. Ultrasonic deformation imaging (strain/strain rate) is sensitive in detecting sub-clinical abnormalities in regional systolic function and could potentially be sufficiently sensitive to detect changes in deformation induced by graft rejection.

Aim: To assess the use of strain (S) and strain rate (SR) imaging as a noninvasive method for monitoring and diagnosing acute rejection in heart transplant recipients.

Methods And Results: A prospective preliminary study was carried out involving 31 consecutive heart transplant patients who underwent a total of 106 routine follow up endomyocardial biopsy with correlative cardiac ultrasound data. To assess regional longitudinal deformation, ultrasonic S and SR data were acquired from the intraventricular septum, left ventricular (LV) lateral and right ventricular free walls (RVFW). For radial deformation, data were obtained from the LV posterior wall (LVPW). According to the International Society of Heart and Lung Transplantation criteria, 88 biopsies (Group 1) had grade 0 or IA rejection, and 18 biopsies (Group 2) had > or =grade IB rejection. Longitudinal peak systolic S and SR were decreased (p<0.05) in Group 2, compared to Group 1 in the RVFW basal and apical segments and the basal and mid segments of the LV lateral wall. Radial peak systolic S and SR were significantly lower (p<0.001) in Group 2, compared to Group 1.

Conclusions: S/SR imaging might be a good technique and an additional tool for detecting > or =IB grade of acute rejection. The myocardial deformation, as assessed by S/SR imaging could be of clinical value in monitoring and diagnosing acute rejection in heart transplant recipients and could improve patients' management by reducing the number of biopsies performed.
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http://dx.doi.org/10.1016/j.euje.2006.03.014DOI Listing
June 2007