Publications by authors named "Uyên Châu Nguyên"

13 Publications

  • Page 1 of 1

Undersensing, asynchronous pacing, and ventricular fibrillation.

Europace 2019 07;21(7):1078

Department of Cardiology, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University Medical Center, Maastricht, the Netherlands.

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http://dx.doi.org/10.1093/europace/euz009DOI Listing
July 2019

Integration of cardiac magnetic resonance imaging, electrocardiographic imaging, and coronary venous computed tomography angiography for guidance of left ventricular lead positioning.

Europace 2019 Apr;21(4):626-635

Department of Cardiology, CARIM, Maastricht University Medical Center, Maastricht, the Netherlands.

Aims: An appropriate left ventricular (LV) lead position is a pre-requisite for response to cardiac resynchronization therapy (CRT) and is highly patient-specific. The purpose of this study was to develop a non-invasive pre-procedural CRT-roadmap to guide LV lead placement to a coronary vein in late-activated myocardium remote from scar.

Methods And Results: Sixteen CRT candidates were prospectively included. Electrocardiographic imaging (ECGI), computed tomography angiography (CTA), and delayed enhancement cardiac magnetic resonance imaging (DE-CMR) were integrated into a 3D cardiac model (CRT-roadmap) using anatomic landmarks from CTA and DE-CMR. Electrocardiographic imaging was performed using 184 electrodes and a CT-based heart-torso geometry. Coronary venous anatomy was visualized using a designated CTA protocol. Focal scar was assessed from DE-CMR. Cardiac resynchronization therapy-roadmaps were constructed for all 16 patients [left bundle branch block: n = 6; intraventricular conduction disturbance: n = 8; narrow-QRS (ablate and pace strategy); n = 1; right bundle branch block: n = 1]. The number of coronary veins ranged between 3 and 4 per patient. The CRT-roadmaps showed no (n = 5), 1 (n = 6), or 2 (n = 5) veins per patient located outside scar in late-activated myocardium [≥50% QRS duration (QRSd)]. Final LV lead position was outside scar in late-activated myocardium in 11 out of 14 implanted patients, while a LV lead in scar was unavoidable in the remaining three patients.

Conclusion: A non-invasive pre-implantation CRT-roadmap was feasible to develop in a case series by integration of coronary venous anatomy, myocardial-scar localization, and epicardial electrical activation patterns, anticipating on clinically relevant features.
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http://dx.doi.org/10.1093/europace/euy292DOI Listing
April 2019

A left bundle branch block activation sequence and ventricular pacing influence voltage amplitudes: an in vivo and in silico study.

Europace 2018 Nov;20(suppl_3):iii77-iii86

Center for Computational Medicine in Cardiology (CCMC), Institute of Computational Science, Università della Svizzera italiana, Lugano, Switzerland.

Aims: The aim of this study was to investigate the influence of the activation sequence on voltage amplitudes by evaluating regional voltage differences during a left bundle branch block (LBBB) activation sequence vs. a normal synchronous activation sequence and by evaluating pacing-induced voltage differences.

Methods And Results: Twenty-one patients and three computer models without scar were studied. Regional voltage amplitudes were evaluated in nine LBBB patients who underwent endocardial electro-anatomic mapping (EAM). Pacing-induced voltage differences were evaluated in 12 patients who underwent epicardial EAM during intrinsic rhythm and right ventricular (RV) pacing. Three computer models customized for LBBB patients were created. Changes in voltage amplitudes after an LBBB (intrinsic), a normal synchronous, an RV pacing, and a left ventricular pacing activation sequence were assessed in the computer models. Unipolar voltage amplitudes in patients were approximately 4.5 mV (4.4-4.7 mV, ∼33%) lower in the septum when compared with other segments. A normal synchronous activation sequence in the computer models normalized voltage amplitudes in the septum. Pacing-induced differences were larger in electrograms with higher voltage amplitudes during intrinsic rhythm and furthermore larger and more variable at the epicardium [mean absolute difference: 3.6-6.2 mV, 40-53% of intrinsic value; interquartile range (IQR) differences: 53-63% of intrinsic value] compared to the endocardium (mean absolute difference: 3.3-3.8 mV, 28-30% of intrinsic value; IQR differences: 37-40% of intrinsic value).

Conclusion: In patients and computer models without scar, lower septal unipolar voltage amplitudes are exclusively associated with an LBBB activation sequence. Pacing substantially affects voltage amplitudes, particularly at the epicardium.
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http://dx.doi.org/10.1093/europace/euy233DOI Listing
November 2018

Late complications of an atrial septal occluder provoked by anticoagulant therapy.

J Cardiol Cases 2018 Feb 7;17(2):68-71. Epub 2017 Nov 7.

Department of Cardiology, Maastricht University Medical Center, Maastricht, The Netherlands.

Late complications of an atrial septal occluder device (ASO) are rare but may be serious. We report a case with extensive hemopericardium five years after ASO implantation most likely triggered by anticoagulant therapy. Although not surgically confirmed, indirect clues for erosion of the atrial wall by the device were the exclusion of other etiologies, lack of recurrence after pericardial drainage and withdrawal of anticoagulants. In addition, multimodality imaging using echocardiography, computed tomography, and cardiac magnetic resonance imaging were helpful to elucidate this unusual cause. Initiation of anticoagulant treatment in patients with an ASO should be carefully balanced and may warrant more frequent echocardiographic follow-up. < Late complications of an atrial septal occlude device (ASO) are rare. Initiation of anticoagulant therapy in patients with an ASO may lead to late hemopericardium, suggesting that more frequent echocardiographic follow-up is warranted.>.
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http://dx.doi.org/10.1016/j.jccase.2017.09.010DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6149637PMC
February 2018

Response to cardiac resynchronization therapy is determined by intrinsic electrical substrate rather than by its modification.

Int J Cardiol 2018 Nov 6;270:143-148. Epub 2018 Jun 6.

IHU Liryc, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université, F-33600 Pessac, Bordeaux, France; Bordeaux University Hospital (CHU), Cardio-Thoracic Unit, F-33600 Pessac, France.

Background: Electrocardiographic mapping (ECM) expresses electrical substrate through magnitude and direction of the activation delay vector (ADV). We investigated to what extent the response to cardiac resynchronization therapy (CRT) is determined by baseline ADV and by ADV modification through CRT and optimization of left ventricular (LV) pacing site.

Methods: ECM was performed in 79 heart failure patients (4 RBBB, 12 QRS < 120 ms, 23 non-specific conduction delay [NICD] and 40 left bundle branch block [LBBB]). 67 patients (QRS ≥ 120 ms) underwent CRT implantation and in 26 patients multiple LV pacing site optimization was performed. ADV was calculated from locations/depolarization times of 2000 virtual epicardial electrodes derived from ECM. Acute response was defined as ≥10% LVdP/dt increase, chronic response by composite clinical score at 6 months.

Results: During intrinsic conduction, ADV direction was similar in patients with QRS < 120 ms, NICD and LBBB, pointing towards the LV free wall, while ADV magnitude was larger in LBBB (117 ± 25 ms) than in NICD (70 ± 29 ms, P < 0.05) and QRS < 120 ms (52 ± 14 ms, P < 0.05). Intrinsic ADV accurately predicted the acute (AUC = 0.93) and chronic (AUC = 0.90) response to CRT. ADV change by CRT only moderately predicted response (highest AUC = 0.76). LV pacing site optimization had limited effects: +3 ± 4% LVdP/dt when compared to conventional basolateral LV pacing.

Conclusion: The baseline electrical substrate, adequately measured by ADV amplitude, strongly determines acute and chronic CRT response, while the extent of its modification by conventional CRT or by varying LV pacing sites has limited effects.
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http://dx.doi.org/10.1016/j.ijcard.2018.06.005DOI Listing
November 2018

Can We Use the Intrinsic Left Ventricular Delay (QLV) to Optimize the Pacing Configuration for Cardiac Resynchronization Therapy With a Quadripolar Left Ventricular Lead?

Circ Arrhythm Electrophysiol 2018 03;11(3):e005912

From the Department of Cardiology, University Medical Center Utrecht, The Netherlands (W.M.v.E., M.J.C., P.A.D., M.M.); Department of Cardiology, Institute for Cardiovascular Research, VU University Medical Center, Amsterdam, The Netherlands (A.Z., A.C.v.R., C.P.A.); Department of Cardiology, Maastricht University Medical Center, The Netherlands (U.C.N., K.V.); and Department of Physiology, CARIM (Cardiovascular Research Institute Maastricht), Maastricht University, The Netherlands (U.C.N., F.W.P.).

Background: Previous studies indicated the importance of the intrinsic left ventricular (LV) electric delay (QLV) for optimal benefit to cardiac resynchronization therapy. We investigated the use of QLV for achieving optimal acute hemodynamic response to cardiac resynchronization therapy with a quadripolar LV lead.

Methods And Results: Forty-eight heart failure patients with a left bundle branch block were prospectively enrolled (31 men; age, 66±10 years; LV ejection fraction, 28±8%; QRS duration, 176±14 ms). Immediately after cardiac resynchronization therapy implantation, invasive LV pressure-volume loops were recorded during biventricular pacing with each separate electrode at 4 atrioventricular delays. Acute cardiac resynchronization therapy response, measured as change in stroke work (Δ%SW) compared with intrinsic conduction, was related to intrinsic interval between Q on the ECG and LV sensing delay (QLV), normalized for QRS duration (QLV/QRSd), and electrode position. QLV/QRSd was 84±9% and variation between the 4 electrodes 9±5%. Δ%SW was 89±64% and varied by 39±36% between the electrodes. In univariate analysis, an anterolateral or lateral electrode position and a high QLV/QRSd had a significant association with a large Δ%SW (all <0.01). In a combined model, only QLV/QRSd remained significantly associated with Δ%SW (<0.05). However, a direct relation between QLV/QRSd and Δ%SW was only seen in 24 patients, whereas 24 patients showed an inverse relation.

Conclusions: The large variation in acute hemodynamic response indicates that the choice of the stimulated electrode on a quadripolar lead is important. Although QLV/QRSd was associated with acute hemodynamic response at group level, it cannot be used to select the optimal electrode in the individual patient.
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http://dx.doi.org/10.1161/CIRCEP.117.005912DOI Listing
March 2018

Pathobiology of cardiac dyssynchrony and resynchronization therapy.

Europace 2018 12;20(12):1898-1909

Department of Physiology, Cardiovascular Research Institute Maastricht, Universiteitssingel 50, ER Maastricht, The Netherlands.

Synchronous ventricular electrical activation is a prerequisite for adequate left ventricular (LV) systolic function. Conduction abnormalities such as left bundle branch block, and ventricular pacing lead to a dyssynchronous electrical activation sequence, which may have deleterious consequences. The present review attempts to connect the various processes involved in the development of 'dyssynchronopathy', and its correction by cardiac resynchronization therapy (CRT). Abnormal electrical impulse conduction leads to abnormal contraction, characterized by regional differences in timing as well as shortening patterns and amount of external work performed. Early activated regions may show 'wasted work', which leads to inefficient action of the entire left ventricle. Moreover, both the development of heart failure (HF) in general and the regional differences in mechanical load lead to structural, electrical, and contractile remodelling processes. These have been demonstrated at the level of the myocardium (asymmetric hypertrophy, fibrosis, prolongation of activation and reduction in repolarization forces, decrease in LV ejection fraction), cell (gap junctional remodelling, derangement of the T-tubular structure), and molecule (under or overexpression of ion channels and contractile proteins subtypes and abnormal calcium handling). The myocardial adaptations to dyssynchrony are 'maladaptive'. This also explains why CRT, unlike most pharmacological treatments, continues to increase its therapeutic effect over time. Finally, better understanding of all processes involved in dyssynchrony and CRT may also lead to new pharmacological agents for treating HF and to novel pacing strategies.
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http://dx.doi.org/10.1093/europace/euy035DOI Listing
December 2018

Relationship between vectorcardiographic QRS, myocardial scar quantification, and response to cardiac resynchronization therapy.

J Electrocardiol 2018 May - Jun;51(3):457-463. Epub 2018 Feb 8.

Department of Physiology, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, The Netherlands.

Purpose: To investigate the relationship between vectorcardiography (VCG) and myocardial scar on cardiac magnetic resonance (CMR) imaging, and whether combining these metrics may improve cardiac resynchronization therapy (CRT) response prediction.

Methods: Thirty-three CRT patients were included. QRS, T and QRST were derived from the ECG-synthesized VCG. CMR parameters reflecting focal scar core (Scar, Gray) and diffuse fibrosis (pre-T1, extracellular volume [ECV]) were assessed. CRT response was defined as ≥15% reduction in left ventricular end-systolic volume after six months' follow-up.

Results: VCG QRS, T and QRST inversely correlated with focal scar (R = -0.44--0.58 for Scar, p ≤ 0.010), but not with diffuse fibrosis. Scar, Gray and QRS predicted CRT response with AUCs of 0.692 (p = 0.063), 0.759 (p = 0.012) and 0.737 (p = 0.022) respectively. A combined ROC-derived threshold for Scar and QRS resulted in 92% CRT response rate for patients with large QRS and small Scar or Gray.

Conclusion: QRS is inversely associated with focal scar on CMR. Incremental predictive value for CRT response is achieved by a combined CMR-QRS analysis.
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http://dx.doi.org/10.1016/j.jelectrocard.2018.01.009DOI Listing
March 2019

Evaluation of the use of unipolar voltage amplitudes for detection of myocardial scar assessed by cardiac magnetic resonance imaging in heart failure patients.

PLoS One 2017 5;12(7):e0180637. Epub 2017 Jul 5.

Center for Computational Medicine in Cardiology, Institute of Computational Science, Università della Svizzera italiana, Lugano, Switzerland.

Background: Validation of voltage-based scar delineation has been limited to small populations using mainly endocardial measurements. The aim of this study is to compare unipolar voltage amplitudes (UnipV) with scar on delayed enhancement cardiac magnetic resonance imaging (DE-CMR).

Methods: Heart failure patients who underwent DE-CMR and electro-anatomic mapping were included. Thirty-three endocardial mapped patients and 27 epicardial mapped patients were investigated. UnipV were computed peak-to-peak. Electrograms were matched with scar extent of the corresponding DE-CMR segment using a 16-segment/slice model. Non-scar was defined as 0% scar, while scar was defined as 1-100% scar extent.

Results: UnipVs were moderately lower in scar than in non-scar (endocardial 7.1 [4.6-10.6] vs. 10.3 [7.4-14.2] mV; epicardial 6.7 [3.6-10.5] vs. 7.8 [4.2-12.3] mV; both p<0.001). The correlation between UnipV and scar extent was moderate for endocardial (R = -0.33, p<0.001), and poor for epicardial measurements (R = -0.07, p<0.001). Endocardial UnipV predicted segments with >25%, >50% and >75% scar extent with AUCs of 0.72, 0.73 and 0.76, respectively, while epicardial UnipV were poor scar predictors, independent of scar burden (AUC = 0.47-0.56). UnipV in non-scar varied widely between patients (p<0.001) and were lower in scar compared to non-scar in only 9/22 (41%) endocardial mapped patients and 4/19 (21%) epicardial mapped patients with scar.

Conclusion: UnipV are slightly lower in scar compared to non-scar. However, significant UnipV differences between and within patients and large overlap between non-scar and scar limits the reliability of accurate scar assessment, especially in epicardial measurements and in segments with less than 75% scar extent.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0180637PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5498065PMC
October 2017

Left ventricular lead positioning in cardiac resynchronization therapy: Mission accomplished?

Heart Rhythm 2017 09 24;14(9):1373-1374. Epub 2017 May 24.

Department of Physiology, Maastricht University Medical Center, Maastricht, The Netherlands; Department of Cardiology, Maastricht University Medical Center, Maastricht, The Netherlands. Electronic address:

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http://dx.doi.org/10.1016/j.hrthm.2017.05.030DOI Listing
September 2017

A novel approach for left ventricular lead placement in cardiac resynchronization therapy: Intraprocedural integration of coronary venous electroanatomic mapping with delayed enhancement cardiac magnetic resonance imaging.

Heart Rhythm 2017 01 20;14(1):110-119. Epub 2016 Sep 20.

Department of Cardiology, Maastricht University Medical Center, Maastricht, the Netherlands.

Background: Placing the left ventricular (LV) lead at a site of late electrical activation remote from scar is desired to improve cardiac resynchronization therapy (CRT) response.

Objective: The purpose of this study was to integrate coronary venous electroanatomic mapping (EAM) with delayed enhancement cardiac magnetic resonance (DE-CMR) enabling LV lead guidance to the latest activated vein remote from scar.

Methods: Eighteen CRT candidates with focal scar on DE-CMR were prospectively included. DE-CMR images were semi-automatically analyzed. Coronary venous EAM was performed intraprocedurally and integrated with DE-CMR to guide LV lead placement in real time. Image integration accuracy and electrogram parameters were evaluated offline.

Results: Integration of EAM and DE-CMR was achieved using 8.9 ± 2.8 anatomic landmarks and with accuracy of 4.7 ± 1.1 mm (mean ± SD). Maximal electrical delay ranged between 72 and 197ms (57%-113% of QRS duration) and was heterogeneously located among individuals. In 12 patients, the latest activated vein was located outside scar, and placing the LV lead in the latest activated vein remote from scar was accomplished in 10 patients and prohibited in 2 patients. In the other 6 patients, the latest activated vein was located in scar, and targeting alternative veins was considered. Unipolar voltages were on average lower in scar compared to nonscar (6.71 ± 3.45 mV vs 8.18 ± 4.02 mV [median ± interquartile range), P <.001) but correlated weakly with DE-CMR scar extent (R -0.161, P <.001) and varied widely among individual patients.

Conclusion: Integration of coronary venous EAM with DE-CMR can be used during CRT implantation to guide LV lead placement to the latest activated vein remote from scar, possibly improving CRT.
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http://dx.doi.org/10.1016/j.hrthm.2016.09.015DOI Listing
January 2017

Comparison between a count-based and geometrical approach for the assessment of left ventricular dyssynchrony using myocardial perfusion scintigraphy.

Nucl Med Commun 2016 Nov;37(11):1125-35

aFaculty of Technical Medicine, University of Twente, Enschede bDepartment of Physiology, Cardiovascular Research Institute Maastricht, Maastricht Departments of cNuclear Medicine dCardiology, Leiden University Medical Centre, Leiden eDepartment of Nuclear Medicine, VieCurie, Venlo fDepartment of Nuclear Medicine, Antoni van Leeuwenhoek Hospital, Netherlands Cancer Institute, Amsterdam, The Netherlands.

Objective: There are two distinct approaches for the assessment of left ventricular (LV) dyssynchrony by myocardial perfusion scintigraphy (MPS). The aim of this study was to compare the performance of the count-based and geometrical approach in clinical data using gated single photon emission computed tomography MPS.

Material And Methods: Group 1 consisted of 113 patients (49 men, 64 women) with normal perfusion [summed rest score (SRS)≤3], normal LV ejection fraction (≥55%), and normal QRS duration (QRSd<120 ms). Group 2 consisted of 89 heart failure patients (79 men, 10 women) with no restriction for SRS, LV ejection fraction ≤35%, and QRSd ≥120 ms. All MPS parameters were obtained from the software Corridor4DM. Dyssynchrony parameters used were time to peak contraction, SD, and bandwidth (BW).

Results: SD and BW were estimated higher (difference group 1: SD 3.0±2.3 and BW 11.3±9.3, P-values <0.001; difference group 2: SD 2.4±4.3 and BW 1.3±17.0, P-value <0.001 and 0.479 respectively) using the count-based approach in comparison with the geometrical method. A significant and good correlation was found between these two methods (R=0.763, 0.902, 0.896 for time to peak contraction, SD, and BW respectively, P-values ≤0.001). SD and BW in both approaches were equally good parameters for differentiating heart failure patients (area under the curve: 0.995-0.998), although using different cut-off values.

Conclusion: The count-based approach generally provides a wider phase distribution and subsequently greater SD and BW estimates compared with the geometrical algorithm. These differences result in clinically relevant deviations in normal and cut-off values that have to be recognized when evaluating patients.
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http://dx.doi.org/10.1097/MNM.0000000000000574DOI Listing
November 2016

An in-silico analysis of the effect of heart position and orientation on the ECG morphology and vectorcardiogram parameters in patients with heart failure and intraventricular conduction defects.

J Electrocardiol 2015 Jul-Aug;48(4):617-25. Epub 2015 May 8.

Center for Computational Medicine in Cardiology, Institute of Computational Science, Università della Svizzera italiana, Lugano, Switzerland; Division of Cardiology, Fondazione Cardiocentro Ticino, Lugano, Switzerland.

Aim: The aim of this study was to investigate the influence of geometrical factors on the ECG morphology and vectorcardiogram (VCG) parameters.

Methods: Patient-tailored models based on five heart-failure patients with intraventricular conduction defects (IVCDs) were created. The heart was shifted up to 6 cm to the left, right, up, and down and rotated ±30° around the anteroposterior axis. Precordial electrodes were shifted 3 cm down.

Results: Geometry modifications strongly altered ECG notching/slurring and intrinsicoid deflection time. Maximum VCG parameter changes were small for QRS duration (-6% to +10%) and QRS-T angle (-6% to +3%), but considerable for QRS amplitude (-36% to +59%), QRS area (-37% to +42%), T-wave amplitude (-41% to +36%), and T-wave area (-42% to +33%).

Conclusion: The position of the heart with respect to the electrodes is an important factor determining notching/slurring and voltage-dependent parameters and therefore must be considered for accurate diagnosis of IVCDs.
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http://dx.doi.org/10.1016/j.jelectrocard.2015.05.004DOI Listing
March 2016