James Pemberton

The Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle-on-Tyne, England, United Kingdom

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Publications (25)77.54 Total impact

  • James Pemberton · Nigel Cooper · Antoinette Kenny

    No preview · Article · Aug 2012 · Archives of cardiovascular diseases
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    James Pemberton · Peter Raudkivi
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    ABSTRACT: A patient presented with shortness of breath, lethargy and weight loss. A computerized tomography and echocardiogram showed a mass in the right ventricle nearly obstructing the pulmonary valve during systole and prolapsing into the main pulmonary artery. The mass was completely excised. Histology was that of a typical myxoma.
    Preview · Article · Dec 2011 · Interactive Cardiovascular and Thoracic Surgery
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    ABSTRACT: Aims: Accurate calculation of left ventricular ejection fraction (LVEF) is important for diagnostic, prognostic and therapeutic reasons. Cardiac magnetic resonance (CMR) is the reference standard for LVEF calculation, followed by real time three-dimensional echocardiography (RT3DE). Limited availability of CMR and RT3DE leaves Simpson's rule as the two-dimensional echocardiography (2DE) standard by which LVEF is calculated. We investigated the accuracy of the 16-Segment Regional Wall Motion Score Index (RWMSI) as an alternative method for calculating LVEF by 2DE and compared this to Simpson's rule and CMR. Methods and Results: The 2D echocardiograms of 110 patients were studied (LVEF range: 7–74%); 57 of these underwent CMR. A RWMS was applied, based on the consensus opinion of two experienced cardiologists, to each of 16 American Heart Association myocardial segments (RWMSI: hyperkinesis = 3; normal regional contraction = 2; mild hypokinesis = 1.25; severe hypokinesis = 0.75; akinesis = 0; dyskinesis =–1). LVEF was calculated by: LVEF(%) =Σ(16segRWMS)/16×30. LVEF was calculated by Simpson's rule and CMR using standard methods. Results were correlated against CMR. Intertechnique agreement was examined. A P value of<0.05 was considered significant. RWMSI-LVEF correlated strongly with Biplane Simpson's rule (P< 0.001, r = 0.915). RWMSI-LVEF had a strong correlation to CMR (P < 0.001, r = 0.916); Simpson's rule-LVEF had a moderate correlation to CMR (P< 0.001, r = 0.647). In patients with LV dysfunction (EF < 55%), on linear regression analysis, RWMSI-LVEF had a better correlation with CMR than Simpson's rule. Further more Simpson's rule overestimated LVEF compared to CMR (mean difference: –6.12 ± 16.44, P = 0.002) whereas RWMSI did not (mean difference: 2.58 ± 14.80, P = NS). Conclusion: RWMSI-LVEF correlates strongly with CMR with good intertechnique agreement. In centers where CMR and RT3DE are not readily available, the use by experienced individuals, of the RWMSI for calculating LVEF may be a more simple, accurate, and reliable alternative to Simpson's rule. (Echocardiography 2011;28:597-604)
    Full-text · Article · Jun 2011 · Echocardiography

  • No preview · Article · Dec 2008 · Heart, Lung and Circulation

  • No preview · Article · Oct 2008 · Heart (British Cardiac Society)

  • No preview · Article · Dec 2007 · Heart, Lung and Circulation
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    ABSTRACT: We have developed an integrated high-resolution intracardiac echocardiography (ICE) catheter for electrophysiology (EP) testing, which can be coregistered in 3-dimensional space with EP testing and ablation catheters using electrofield sensing. Twelve open-chest pigs (34-55 kg) and 3 closed-chest pigs were studied. After introduction from the jugular or femoral venous locations, the 9F side-looking, highly steerable (0 degrees -180 degrees), 64-element array catheters could be manipulated easily throughout the right side of the heart. Multisite cardiac pacing was performed for assessing left ventricular (LV) synchrony using tissue Doppler methods. Also, in the open-chest pigs, right atrial (RA) and right ventricular (RV) ablations were performed with a separate radio frequency catheter under fluoroscopic guidance and visualized with ICE to characterize the changes. In the 3 closed-chest pigs, electrofield NavX 3-dimensional coregistration (St Jude Medical Corp, Minneapolis, MN) allowed us to test whether this additional feature could shorten the time necessary to perform 4 targeted ablations in each animal while imaging the ablation catheter and the adjacent region by ICE. Intracardiac anatomy, tricuspid, aortic, pulmonary, and mitral valve function, and pulmonary vein flow were all imaged reproducibly from scanning locations in the RA or RV in all animals, along with assessment of cardiac motion and the effects of multisite pacing. Three-dimensional electrofield displays detailed the spatial relationship between the ICE catheter and ablation catheters such that the time to visualize and ablate 4 sites in each of the 3 closed-chest animals was reduced. This new technology is a first step in the integration of ICE with EP procedures.
    No preview · Article · Dec 2007 · Journal of ultrasound in medicine: official journal of the American Institute of Ultrasound in Medicine
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    J. Wild · A. J. Sims · J. Pemberton · A. Kenny · A. Murray
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    ABSTRACT: Three dimensional echocardiography offers the benefit of non-invasive measurement of chamber volume at the cost of increased effort of data handling. Automated or semi-automated image analysis may help to reduce manual effort but can embody assumptions and limitations which have a significant effect on results. We used a laboratory balloon phantom to study the effect ofthree factors used in a semi-automated image analysis technique. These factors were: a) the use of 2D or 3D image gradient operators; b) manual or automatic detection of base; c) fixed or case-by-case limit of short-axis radius. We found that 3D image gradient operators were more accurate than their traditional 2D counterparts; that manual identification of the base had no effect on accuracy or repeatability, and that setting the maximum short axis radius on a case-by-case basis was more accurate and re- peatable than achieved with a constant value.
    Full-text · Article · Sep 2007 · Computers in cardiology
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    ABSTRACT: Torsion is an essential component of left ventricular (LV) function. Systolic rotation, as a component of torsion, winds the heart muscle up like a spring, setting up recoil for early diastole. We used a new 2-dimensional speckle tracking strain method to study differences in twisting in subendocardial and subepicardial layers of the LV in open-chest pigs. Our aim was to identify the relative contributions of the inner or outer layers of the LV wall to rotation and, hence, systole. A total of 23 juvenile pigs were imaged in the short axis, epicardially, to obtain images at a level just below the papillary muscles with high-frequency (14 MHz) ultrasound. Speckle tracking software using scanline files was used to measure the torsional contribution of septum, anterior, posterior, and inferior LV wall segments. Two zones on the septum were evaluated separately: one with apparent circumferential fiber orientation in the inner layer and one with a speckle pattern suggesting longitudinal fiber orientation on the right ventricular aspect of the septum. Pressure rate changes (dP/dt) during the cardiac cycle were measured as an index of LV function and correlated with the regional torsion. Mean peak rotations measured by speckle tracking echocardiography at the apex showed counterclockwise rotation of LV septal wall (10.68 +/- 2.67 degrees for the inner layer and 8.27 +/- 1.73 degrees for the outer layer). The time difference for time to peak rotation was 213.22 +/- 77.95 and 241.17 +/- 54.67 milliseconds for inner and outer layers, respectively. Significant differences were shown between the inner and outer layer of the LV for both rotation (P = .000) and timing of rotation (P = .02). The dP/dt measurements correlated well with the inner rotation magnitude of the LV and with the difference of short-axis rotation between inner and outer layers of the LV wall. Inner and outer layers of the LV wall, especially at the septum, have different rotational behaviors. When used with very high-resolution imaging, this method could contribute to the understanding of functional contributions of the LV wall and their relative contribution to cardiac segmental twisting.
    Full-text · Article · Jun 2007 · Journal of the American Society of Echocardiography: official publication of the American Society of Echocardiography
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    ABSTRACT: Platypnoea orthodeoxia syndrome is a rare condition in which shortness of breath and hypoxaemia occur when upright and resolve when prone. The hypoxaemia results from increased right to left shunting of deoxygenated blood, when standing, through a patent foramen ovale (PFO), atrial septal defect (ASD) or other right to left shunt, in the absence of raised right-heart pressure. We present the case of a patient with platypnoea orthodeoxia with marked shunting through a large PFO, evaluated by transesophageal and transthoracic echo.
    Preview · Article · Apr 2007 · European Heart Journal – Cardiovascular Imaging
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    ABSTRACT: Real-time 3-dimensional echocardiography is increasingly used in clinical cardiology. Studies have been shown that this technique can be accurately used to assess both cardiac mass and chamber volumes. We review the work showing that real-time 3-dimensional Doppler echocardiography can be used to accurately calculate intracardiac flow volumes that can potentially be used to assess cardiac function, intracardiac shunt, and valve regurgitation.
    No preview · Article · Dec 2006 · Journal of the American Society of Echocardiography: official publication of the American Society of Echocardiography
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    ABSTRACT: Normal left ventricular contraction involves a twisting component that helps augment stroke volume, the unwinding of which also very usefully contributes to early diastolic filling. Abnormalities of cardiac twist have been related to abnormal cardiac function. We sought to quantify the twisting action using a new sonographically based angle-independent motion-detecting echo method. A twist model was developed with a variable-speed motor to rotate a wheel in water bath. A freshly harvested pig heart was mounted on it as a twist phantom. Short axis views were acquired with a GE/VingMed Vivid 7 system (GE Healthcare, Milwaukee, WI) at 3.5 MHz and more than 100 frames/s. Eight different speeds (30-100 cycles/min of winding and unwinding) were studied at 5 degrees of rotation (10 degrees , 20 degrees , 30 degrees , 40 degrees , and 50 degrees ). Data were analyzed off-line for twist analysis with a new 2-dimensional speckle-tracking-based program (2-dimensional strain rate method [2DSR]) embedded in EchoPac software (GE Healthcare). Ten freshly harvested pig hearts were studied in this model. The 2DSR program tracked the twist well (mean determination at 10 degrees = 16.88 degrees +/- 1.81 degrees [SD]; at 20 degrees = 26.5 degrees +/- 1.05 degrees ; at 30 degrees = 36.47 degrees +/- 1.31 degrees ; at 40 degrees = 44.03 degrees +/- 1.39 degrees ; and at 50 degrees = 54.1 degrees +/- 1.96 degrees ). The 2DSR program can be used to study twisting action of the heart.
    No preview · Article · Oct 2006 · Journal of ultrasound in medicine: official journal of the American Institute of Ultrasound in Medicine
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    ABSTRACT: Laminar flow stroke volume (SV) quantification in the ascending aorta or pulmonary artery can provide a measure for determining cardiac output (CO). Comparing flows across different valves can also compute shunt volumes and regurgitant fractions. Quantification methods for 3D color Doppler laminar flow volumes have been developed using reconstructive 3D, but these are cumbersome and time-consuming both in acquisition and measurement. Our study evaluated newly developed color Doppler mapping with real-time live 3D echo to test velocity, spatial and temporal resolution for computing SV. Five rubber tubes (diameters=3.0, 2.25, 2.0, 1.9, 1.7 cm), a freshly dissected porcine aorta (Ao) and a pulmonary artery (PA) (both 2-3 cm diameter) were connected to a pulsatile pump in a water bath. Different SV, from 10 to 80 ml/beat, were studied at pump rates of 40-60 bpm in this phantom model with flow quantified by timed collection. The Nyquist limit was set between 43 and 100 cm/s and frame rate ranged from 14 to 23/s. ECG triggered 3D color Doppler volumes were acquired with a 2-4 MHz probe. The digital scan line data from the 3D volumes, with retained velocity assignments, was exported and analyzed offline by MatLab custom software. Close correlations were found between 3D calculated SV and reference data for all tubes (r=0.98, y=1.14x-1.69, SEE=2.82 ml/beat, p<0.0001). Both Ao and PA flows were also highly correlated with the reference measurements (PA: r=0.98, SEE=3.17 ml/beat; Ao: r=0.99, SEE=3.20 ml/beat). Real-time 3D color Doppler method could provide an efficient, accurate and reliable method for clinical evaluation and quantification of flow volumes in patients.
    Full-text · Article · Dec 2005 · European Heart Journal – Cardiovascular Imaging
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    ABSTRACT: Invasive monitors and noninvasive 2-dimensional echocardiography are the standard clinical methods for stroke volume (SV) and cardiac output computation. We studied the use of real-time color Doppler 3-dimensional (3D) echocardiography (3DE) for the assessment of SV in human beings. In all, 55 pediatric and adult patients with good transthoracic windows and a normal aortic valve were studied. Real-time 3DE color Doppler volumes incorporating the left ventricular outflow tract and aortic valve were taken. SV was calculated from the color Doppler data in the 3DE DICOM dataset. This was compared with 2-dimensional echocardiography SV calculation from the pulsed wave velocity through the aortic valve along with the left ventricular outflow tract diameter. Five patients were excluded because of mismatching of the 3D color Doppler segments in the 3D volume. The 3D Doppler volumes from the remaining 50 patients were analyzed. There was good correlation between the patients' averaged 3DE SV calculations and the 2-dimensional echocardiography pulsed wave SV estimation (y = 0.84x + 7.8, r2 = 0.90). Real-time 3D Doppler echocardiography can be used to accurately calculate SV and cardiac output, compared with conventional pulsed Doppler measurement, in pediatric and adult patients from transthoracic imaging.
    No preview · Article · Nov 2005 · Journal of the American Society of Echocardiography: official publication of the American Society of Echocardiography
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    ABSTRACT: Visualization of myocardial perfusion is possible in both 2-dimensional and from reconstructive 3-dimensional echocardiography. We present the findings of our experimental pilot study of myocardial perfusion detection using live real-time 3-dimensional echocardiography in an animal model.
    No preview · Article · Oct 2005 · Journal of the American Society of Echocardiography: official publication of the American Society of Echocardiography
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    ABSTRACT: We and others have reported on the use of digital color Doppler sonography from real-time 3-dimensional (3D) echocardiography and its use in accurately calculating cardiac flow volumes, namely stroke volume (SV) and, hence, cardiac output. However, in some patients, image depth is higher than average, and this may affect the accuracy of volume calculation. We sought to investigate the impact of image depth and the accompanying change in signal strength, spatial resolution, and pulse repetition frequency on the accuracy of SV calculation from 3D color Doppler data in an in vitro model. A tube model of the left ventricular outflow tract was constructed from plastic tubing and connected to a pulsatile pump. The volume flowing through the tube was imaged using a 3D echocardiography system. Stroke volumes from the pump were computed from the DICOM data using commercially available software and compared with a reference standard of timed volumes with the use of a graduated measuring cylinder over a range of depth settings and SVs. There was good correlation between the 3D-derived SVs and the reference cylinder measures over all depths from 4 to 16 cm at 1-cm increments with a tube diameter of 17 mm, a pump rate of 60 beats/min, and SVs ranging from 20 to 70 mL. The average r(2) value for the 13 different depths was 0.976. However, the accuracy of the 3D method of volume calculation appeared to fall at depths greater than 13 cm, especially at higher SVs. Stroke volume calculation from real-time 3D color Doppler data in this in vitro study shows that at depths greater than approximately 13 cm, accuracy decreases, especially at higher SVs. This may be due to decreased resolution and the reduced frame rate at these depths. At shallower depths, volume calculation form the 3D Doppler data appears very accurate.
    No preview · Article · Sep 2005 · Journal of ultrasound in medicine: official journal of the American Institute of Ultrasound in Medicine
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    ABSTRACT: The purpose of this study was to investigate whether cardiac output (CO) could be accurately computed from live three-dimensional (3-D) Doppler echocardiographic data in an acute open-chested animal preparation. The accurate measurement of CO is important in both patient management and research. Current methods use invasive pulmonary artery catheters or two-dimensional (2-D) echocardiography or esophageal aortic Doppler measures, with the inherent risks and inaccuracies of these techniques. Seventeen juvenile, open-chested pigs were studied before undergoing a separate cardiopulmonary bypass procedure. Live 3-D Doppler echocardiography images of the left ventricular outflow tract and aortic valve were obtained by epicardial scanning, using a Philips Medical Systems (Andover, Massachusetts) Sonos 7500 Live 3-D Echo system with a 2.5-MHz probe. Simultaneous CO measurements were obtained from an ultrasonic flow probe placed around the aortic root. Subsequent offline processing using custom software computed the CO from the digital 3-D Doppler DICOM data, and this was compared to the gold standard of the aortic flow probe measurements. One hundred forty-three individual CO measurements were taken from 16 pigs, one being excluded because of severe aortic regurgitation. There was good correlation between the 3-D Doppler and flow probe methods of CO measurement (y = 1.1x - 9.82, R(2) = 0.93). In this acute animal preparation, live 3-D Doppler echocardiographic data allowed for accurate assessment of CO as compared to the ultrasonic flow probe measurement.
    Full-text · Article · Mar 2005 · Journal of the American College of Cardiology
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    ABSTRACT: The earliest heart movements in the valveless curved embryonic heart tube were believed to be poorly synchronized and almost peristaltic.
    No preview · Conference Paper · Feb 2005
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    James Pemberton · David J Sahn
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    ABSTRACT: The aorta is an integral part of the cardiovascular system and should not be considered as just a conduit for blood supply from the heart to the limbs and major organs. A range of important pathologies affect the aorta and are responsible for a high level of morbidity and mortality in affected patients. Many of these conditions are seen in the adult congenital population, especially as advances in diagnosis and treatment mean these patients are surviving well into adulthood. As we gain a greater understanding of these disorders, especially the underlying genetics and pathophysiology, it becomes clear that the aorta is a highly complex part of the vascular tree. As such, the aorta requires increasingly sophisticated imaging techniques for the diagnosis, treatment and follow-up of these patients. The advantages and disadvantages of the various imaging techniques available to clinicians will be discussed in the context of both acute and chronic aortic pathology.
    Full-text · Article · Jan 2005 · International Journal of Cardiology
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    J. Wild · A.J. Sims · J. Pemberton · T. Irvine · A. Kenny · A. Murray
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    ABSTRACT: Left ventricular volume is an important clinical indicator for the diagnosis and the monitoring of treatment of many heart diseases. Automated quantification using echocardiography is challenging due to inherent image artefacts. In this paper, three different methods for calculating left ventricular volume were compared. 3D images of the left ventricle (LV) were reconstructed from rotationally acquired B-mode images for six patients at end-diastole and end-systole. By manual selection of the LV long-axis centre line, virtual, contiguous perpendicular short-axis images could be extracted. The LV wall was then detected by using (a) circle fitting, (b) smoothing between circles, and (c) greedy snake. Results of this study showed that there was no significant difference between chamber volume estimated by all three techniques.
    Full-text · Conference Paper · Oct 2004

Publication Stats

231 Citations
77.54 Total Impact Points


  • 2002-2012
    • The Newcastle upon Tyne Hospitals NHS Foundation Trust
      • Department of Cardiology
      Newcastle-on-Tyne, England, United Kingdom
  • 2011
    • Newcastle University
      • Institute of Cellular Medicine
      Newcastle-on-Tyne, England, United Kingdom
    • Auckland City Hospital
      • Department of Cardiothoracic Surgery
      Окленд, Auckland, New Zealand
  • 2004-2008
    • Oregon Health and Science University
      • Department of Diagnostic Radiology
      Portland, Oregon, United States
  • 2006
    • James Cook University
      Townsville, Queensland, Australia