Chi Keong Ching

National Heart Centre Singapore, Tumasik, Singapore

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Publications (49)179.2 Total impact

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    ABSTRACT: A 45-year-old man with normal heart structure and function underwent an electrophysiology study for recurrent palpitations. Catheters were placed in the coronary sinus, right ventricular apex and at the His bundle. The baseline electrocardiogram was normal with subtle preexcitation and normal intervals (AH 87ms, HV 50ms). There was poor VA conduction and evident VA dissociation during retrograde conduction studies. Atrial double extra-stimuli showed progressive prolongation of the AH interval with induction of a narrow complex tachycardia of cycle length 440 ms (Fig. 1). The QRS shortened at the onset of tachycardia with subtle changes in the surface electrocardiogram. There was VA dissociation during the tachycardia. A premature ventricular complex (PVC) during His refractory advanced the subsequent His and reset the tachycardia (Fig. 2). This article is protected by copyright. All rights reserved.
    Journal of Cardiovascular Electrophysiology 11/2015; DOI:10.1111/jce.12878 · 2.96 Impact Factor
  • K. Chua · Y. Go · C. Sivathasan · C. Lim · D.K. Sim · C. Ching · C. Ng ·

    The Journal of Heart and Lung Transplantation 04/2015; 34(4):S199-S200. DOI:10.1016/j.healun.2015.01.547 · 6.65 Impact Factor
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    ABSTRACT: AimThe aim of this study was to test the hypothesis that diabetes modifies the risk of mortality in acute heart failure patients, especially in patients with impaired LVEF, and that impaired LVEF in turn modifies the risk of mortality in diabetic patients. Methods and resultsWe studied 2121 patients with acute heart failure admitted at two centres in Singapore from 1 January 2008 to 31 December 2009. The date of the last follow-up was 31 December 2011, with a median follow-up time (interquartile range) of 914 (442-1190) days. Cox regression was used to estimate hazard ratios for all-cause mortality in patients with LVEF 50%, LVEF 30-49%, and LVEF <30% relative to diabetic status. Impaired LVEF (<50%) in the presence of diabetes substantially increased the risk of mortality compared with non-diabetics with LVEF <50%. The adjusted hazard ratio (aHR) and 95% confidence interval (CI) for diabetic patients with an LVEF of 30-49% (1.46, 95% 1.18-1.81) was not statistically different from the aHR in non-diabetic patients with severely impaired LVEF of <30% (1.38, 95% CI 1.09-1.75) (P = 0.644). The deleterious effects of diabetes seemed to be confined to acute heart failure patients with impaired LVEF, as the mortality rate in patients with LVEF >50% was not increased. Other clinical predictors of mortality were ageing, prior myocardial infarction, systolic blood pressure >140 mmHg, creatinine 250 mu mol/L, haemoglobin <9.0 g/dL, and prior stroke/transient ischaemic attack. Conclusion The interaction of diabetes and impaired LVEF in acute heart failure patients significantly amplifies the deleterious effects of each as distinct disease entities.
    European Journal of Heart Failure 11/2014; 16(11). DOI:10.1002/ejhf.119 · 6.53 Impact Factor
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    ABSTRACT: Background: Heart failure with preserved ejection fraction (HF-PEF) has been shown to be of better or equivalent prognosis than heart failure with reduced ejection fraction (HF-REF). We aimed to characterize and study the outcome of HF-PEF in a multiethnic South East Asian context. Methods: This is a single-centre retrospective analysis of 312 patients admitted with decompensated heart failure over 1 year from January to December 2009. We evaluated clinical characteristics of patients according to left ventricular ejection fraction at least 50 or less than 50%. Outcomes as defined by 1-year mortality and 90-day re-hospitalization rates for heart failure were compared between the two groups in an in-patient setting. Results: The median age was 68 years and median length of hospitalization was 4 days. Around 21.8% had HF-PEF. Patients with preserved ejection fraction were more often older, female, hypertensive, with atrial fibrillation, had no coronary artery disease and had never smoked before. They were less often prescribed antiplatelets, angiotensin-converting enzyme inhibitor/angiotensin-II receptor blocker, aldosterone-receptor antagonists, digoxin and loop diuretics. After 1 year, mortality was 5.9% in patients with HF-PEF and 11.3% in those with HF-REF, but the difference was nonsignificant (P = 0.195). There was also no difference in 90-day rehospitalization rates between the groups (16.2 vs. 17.6%, respectively, P = 0.780). Poor prognostic factors for the cohort of heart failure patients included increased age, diabetes and renal impairment, but not left ventricular ejection fraction. Conclusion: HF-PEF is associated with distinct risk factors from HF-REF, but has a similar morbidity and mortality to HF-REF.
    Journal of Cardiovascular Medicine 07/2014; Publish Ahead of Print(9). DOI:10.2459/JCM.0000000000000100 · 1.51 Impact Factor
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    03/2014; 9(1):e168. DOI:10.1016/j.gheart.2014.03.1826
  • Choon Ta Ng · Jason See · Chee Wan Lee · C.-K. Ching ·
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    ABSTRACT: The authors illustrate the successful ablation of a left-sided posterior accessory pathway via a retrograde aortic approach in a patient with coronary ostial atresia associated with persistent left-sided superior vena cava. This is an extremely rare anomaly which should be considered by cardiac electrophysiologists when there is difficulty cannulating the coronary sinus via the right atrial route. Awareness of this route obviates the need for additional venous access.
    Heart Asia 01/2014; 6(1):128-129. DOI:10.1136/heartasia-2014-010563
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    ABSTRACT: A 48-year-old male patient underwent cardiac resynchronization therapy defibrillator implantation, and he was found to have atresia of the coronary sinus ostium with venous drainage occurring via a persistent left-sided superior vena cava, which was connected to the right-sided superior vena cava by the innominate vein. This is a rare benign cardiac anomaly that can pose problems when the coronary sinus needs to be cannulated. To identify the course of the coronary sinus, a coronary angiogram can be performed with attention directed to the venous phase of the angiogram. Although the technical difficulty of coronary sinus cannulation increases, various catheters, wires, and delivery systems can be utilized and this anomaly does not usually prevent successful left ventricular lead placement in cardiac resynchronization therapy via a left-sided superior vena cava approach. There however needs to be consideration regarding caliber of the left-sided superior vena cava being sufficiently large to avoid compromise of venous drainage after lead insertion.
    International Journal of Angiology 09/2013; 22(3):199-202. DOI:10.1055/s-0033-1348882
  • Daniel Tt Chong · Boon Yew Tan · Kah Leng Ho · Wee Siong Teo · Chi Keong Ching ·

    Annals of the Academy of Medicine, Singapore 09/2013; 42(9):480-2. · 1.15 Impact Factor
  • Daniel Chong · Boon Yew Tan · Kah Leng Ho · Wee Siong Teo · Chi Keong Ching ·

    Europace 06/2013; 15(8). DOI:10.1093/europace/eut205 · 3.67 Impact Factor
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    Choon Ta Ng · Aaron Wong · Foong-Koon Cheah · Chi Keong Ching ·

    Heart Asia 01/2013; 5(1):15. DOI:10.1136/heartasia-2012-010234
  • Amit Kumar Malik · Chi Keong Ching · Wee Siong Teo ·
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    ABSTRACT: a b s t r a c t The combineduseofanAmplatzguidingcatheterandsupportcathetercreatesaprogressively supportiverailtoimplanttheleftventricular(LV)leadindifficultcardiacresynchronizationtherapy deviceimplantation.Wedescribethecaseofa32-year-oldmalewithnon-ischaemiccardiomyopathy, left bundle-branchblock,andanLVejectionfractionof30%,whowasreferredtoourcentreforarepeat attemptatanLVleadimplant.Previously,theimplanterhadbeenunabletoadvancedifferentguide cathetersoverthewiretothedesiredtributaryofthecoronarysinus(CS).Atourcentre,theCSwas cannulatedwitha6-FrAL2coronaryguidingcatheter.A135-cmsupportcatheter(SpectraneticsQuick- Cross)wasadvancedviaAL2guidingoverthe0.035in.guidewiretothedistalCS.Theproximalluer fitting ofthesupportcatheterwascutandaninnersheath(MedtronicATTAINSELECTII)advancedover the supportcatheterintotheCS.A4-Frover-the-wireLVleadwasadvancedthroughtheinnersheath over a0.014in.percutaneoustransluminalcoronaryangioplastywireafterremovalofthesupport catheter.Theuseofasupportcatheterservesasrailfortheplacementoftheinnersheathdeepinthe CS andfacilitatesimplantationoftheLVpacinglead.Thistechniqueissafeandeasilyapplied.
    Journal of Arrhythmia 08/2012; 28(4):225-227. DOI:10.1016/j.joa.2011.11.005
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    ABSTRACT: AimsGuidelines from the ESC and ACC/AHA recommend implantable cardioverter defibrillators (ICDs) be implanted in clinically indicated patients with a reasonable expectation of >1 year survival. Our study aimed to assess if selected clinical markers of organ dysfunction were associated with increased 1-year mortality despite ICD therapy.Methods and resultsWe retrospectively studied 283 patients with de novo ICDs implanted for primary or secondary prevention in ischaemic heart disease and dilated cardiomyopathy. We investigated the association of the following clinical markers of organ dysfunction with 1 year mortality: liver dysfunction (aspartate transaminase/alanine transaminase ≥ 3× upper limit of normal or prothrombin time/international normalized ratio ≥ 1.5 in the absence of anticoagulation), respiratory dysfunction (recent mechanical ventilation within 3 months prior to ICD implant), renal dysfunction (creatinine ≥150 mol/L or glomerular filtration rate ≤ 30 mL/min/1.73 m2), anaemia (Hb ≤ 100 g/L), and prior cerebral vascular injury. With no organ dysfunction, 1 year mortality was 1.9%. In the presence of a single organ dysfunction, mortality was increased to 14.3%. With two or more markers of organ dysfunction mortality was 38.1% at 1 year (log-rank test P < 0.001).Conclusions Clinical markers of liver dysfunction, recent mechanical ventilation, and renal impairment were independently associated with increased 1 year mortality. Presence of more than one clinical marker of organ dysfunction was associated with significantly increased risk of mortality in our study.
    Europace 07/2012; 15(4). DOI:10.1093/europace/eus225 · 3.67 Impact Factor
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    ABSTRACT: BACKGROUND: Fragmented QRS complexes (fQRS) correlate with myocardial scar, and may predict arrhythmias in patients with repaired tetralogy of Fallot (TOF). We investigated the relationship between fQRS in operated TOF patients with right ventricular (RV) dysfunction and RV outflow tract (RVOT) aneurysm. METHODS: We studied 56 operated TOF patients with moderate/severe pulmonary regurgitation, referred for cardiac magnetic resonance imaging (MRI) over a 4.5year period. The presence of fQRS (additional notches in the R/S wave in ≥2 contiguous leads on the ECG) was correlated with MRI findings. RESULTS: fQRS was observed in 44 (78.6%) patients. Patients with fQRS had significantly larger RV end diastolic volume index (RVEDVi; 162ml vs 141ml, p=0.028) and RV end systolic volume index (RVESVi; 88ml vs 70ml, p=0.031). Increasing number of leads with fragmentation was independently associated with increasingly lower RV ejection fraction (adjusted co-efficient -0.97, 95%CI -1.83 to -0.12, p=0.026), greater pulmonary regurgitation fraction (1.65, 0.28 to 3.01, p=0.019), larger RVEDVi (6.78, 2.00 to 11.56, p=0.006) and RVESVi (5.41, 1.66 to 9.15, p=0.005). Anterior fragmentation correlated most significantly with RV dysfunction (p<0.05). fQRS had no significant association with LV dysfunction. Presence of any fQRS (OR 17.5, 95%CI 2.1-147.8, p=0.009) and inferior fQRS (OR 9.0, 95%CI 2.7-30.1, p<0.001) were found to be significant predictors for RVOT aneurysm. CONCLUSIONS: The presence of fQRS on the ECG is significantly associated with RV dysfunction and RVOT aneurysms in repaired TOF patients. Increasing burden of fragmentation, especially in the anterior leads, is associated with increasing RV dysfunction.
    International journal of cardiology 04/2012; 167(4). DOI:10.1016/j.ijcard.2012.04.004 · 4.04 Impact Factor
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    ABSTRACT: Ablation of sinus node reentrant tachycardia (SNRT) may be difficult with risk of sinus node injury by using conventional catheters. We report successful ablation of SNRT by using remote magnetic navigation system (Stereotaxis).
    Europace 03/2012; 14(3):455-6. DOI:10.1093/europace/eur283 · 3.67 Impact Factor
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    ABSTRACT: Resting 12-lead electrocardiograms (ECGs) have been employed in the pre-participation evaluation of young asymptomatic subjects to detect pre-existing heart diseases. Although the incorporation of routine ECG in pre-participation screening remains controversial, there is increasing evidence that cardiomyopathies and ion channelopathies have ECG changes as the initial manifestation. The causes of sudden cardiac death in young people show significant geographical variation. We aim to determine the prevalence and spectrum of ECG abnormalities in a young male South-East Asian population. The Singapore Armed Forces Electrocardiogram and Echocardiogram (SAFE) protocol is an ECG-based pre-participation cardiac screening programme modelled after the Italian system. From October 2008 to May 2009, a total of 18 476 young male conscripts (mean age 19.5 years old, range 16-27) underwent mandatory pre-enlistment medical screening at a single medical facility. Subjects with abnormal ECG findings were classified into two groups: Group A had ECG changes that fulfilled a pre-specified checklist to screen for hypertrophic cardiomyopathy and were referred for transthoracic echocardiogram; Group B had other ECG abnormalities [such as Brugada pattern, Wolff-Parkinson-White (WPW) pattern, long QTc] and were referred for secondary screening at a tertiary institution. Of the 18 476 subjects screened, 7.0% (n= 1285) had ECG abnormalities. Of note, 19 (0.10%) had Brugada pattern, 25 (0.14%) had WPW pattern, and 31 (0.17%) had prolonged QT interval on ECG. The prevalence of ECG abnormalities was significantly higher in Chinese than in South Asians (7.2 vs. 5.7%, P= 0.003). The prevalence of ECG abnormalities in a young, South-East Asian male population was 7.0%. There were significant ethnic differences, with ECG abnormalities more prevalent in Chinese than in South Asians (7.2 vs. 5.7%, P= 0.003). The inclusion of universal ECG, in addition to history and physical examination, may increase the sensitivity of a cardiovascular screening programme. Knowledge of the spectrum and prevalence of ECG abnormalities and disease conditions would be pivotal in designing customized screening programmes.
    Europace 02/2012; 14(7):1018-24. DOI:10.1093/europace/eur424 · 3.67 Impact Factor
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    ABSTRACT: Dronedarone restores sinus rhythm and reduces hospitalization or death in intermittent atrial fibrillation. It also lowers heart rate and blood pressure and has antiadrenergic and potential ventricular antiarrhythmic effects. We hypothesized that dronedarone would reduce major vascular events in high-risk permanent atrial fibrillation. We assigned patients who were at least 65 years of age with at least a 6-month history of permanent atrial fibrillation and risk factors for major vascular events to receive dronedarone or placebo. The first coprimary outcome was stroke, myocardial infarction, systemic embolism, or death from cardiovascular causes. The second coprimary outcome was unplanned hospitalization for a cardiovascular cause or death. After the enrollment of 3236 patients, the study was stopped for safety reasons. The first coprimary outcome occurred in 43 patients receiving dronedarone and 19 receiving placebo (hazard ratio, 2.29; 95% confidence interval [CI], 1.34 to 3.94; P=0.002). There were 21 deaths from cardiovascular causes in the dronedarone group and 10 in the placebo group (hazard ratio, 2.11; 95% CI, 1.00 to 4.49; P=0.046), including death from arrhythmia in 13 patients and 4 patients, respectively (hazard ratio, 3.26; 95% CI, 1.06 to 10.00; P=0.03). Stroke occurred in 23 patients in the dronedarone group and 10 in the placebo group (hazard ratio, 2.32; 95% CI, 1.11 to 4.88; P=0.02). Hospitalization for heart failure occurred in 43 patients in the dronedarone group and 24 in the placebo group (hazard ratio, 1.81; 95% CI, 1.10 to 2.99; P=0.02). Dronedarone increased rates of heart failure, stroke, and death from cardiovascular causes in patients with permanent atrial fibrillation who were at risk for major vascular events. Our data show that this drug should not be used in such patients. (Funded by Sanofi-Aventis; PALLAS number, NCT01151137.).
    New England Journal of Medicine 11/2011; 365(24):2268-76. DOI:10.1056/NEJMoa1109867 · 55.87 Impact Factor
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    ABSTRACT: Hypertrophic cardiomyopathy is a leading cause of sudden cardiac death (SCD) in young people in the USA. Pre-participation screening for athletes might reduce the incidence of SCD. In Singapore, military service is compulsory for all young able-bodied male citizens. The Singapore Armed Forces Electrocardiogram and Echocardiogram (SAFE) pre-participation screening protocol based on the Italian programme was introduced. This study evaluates the prevalence of hypertrophic cardiomyopathy (HCM) in a young male South-East Asian population. From October 2008 to May 2009, all male military conscripts underwent pre-participation screening. For all conscripts whose electrocardiogram (ECG) findings fulfilled any of these pre-specified criteria (Group A), direct referral for a transthoracic echocardiogram was mandatory. Conscripts with ECG findings other than pre-specified criteria (e.g. T-wave inversions, repolarization abnormalities) were referred for secondary screening by cardiologists (Group B), which could include echocardiography. Out of 18 476 subjects screened during the study period, 988 (5.3%) subjects were fast tracked for echocardiogram (Group A). Of them, there were three (0.3%) cases with severe abnormalities; there was one case each of HCM, bicuspid aortic valve with significant aortic valve regurgitation, and atrial septal defect with right ventricular systolic dysfunction. The patient with HCM had left axis deviation on ECG. None of the 215 patients who underwent echocardiography following cardiology consult (Group B) had HCM. The prevalence of HCM in our young male population (mean age 19.5, range 16-27) using an ECG-based screening protocol was 0.005%; this appeared lower than published data from other geographical cohorts. Possible explanations include a later age of phenotypic manifestation in our population, limitations of the ECG criteria for screening, or a truly lower prevalence of HCM. More population-based longitudinal studies would be needed to ascertain the true prevalence of HCM in our South-East Asian population.
    Europace 06/2011; 13(6):883-8. DOI:10.1093/europace/eur051 · 3.67 Impact Factor
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    ABSTRACT: Cardiac electric therapies effectively terminate tachyarrhythmias. Recent data suggest a possible increase in long-term mortality associated with implantable cardioverter-defibrillator shocks. Little is known about the association between external cardioversion episodes (ECVe) and long-term mortality. We sought to assess the safety of repeated ECVe with regard to cardiovascular mortality and morbidity. We analyzed the data of the 4060 patients from the AFFIRM (Atrial Fibrillation Follow-up Investigation of Rhythm Management) trial. In particular, associations of ECVe with all-cause mortality, cardiovascular mortality, and hospitalizations after ECVe were studied. Over an average follow-up of 3.5 years, 660 (16.3%) patients died, 331 (8.2%) from cardiovascular causes. A total of 207 (5.1%) and 1697 (41.8%) patients had low ejection fraction and nonparoxysmal atrial fibrillation, respectively; 2460 patients received no ECVe, whereas 1600 experienced ≥ 1 ECVe. Death occurred in 412 (16.7%), 196 (16.5%), 39 (13.5%), and 13 (10.4%) of patients with 0, 1, 2, and ≥ 3 ECVe, respectively. There was no significant association between ECVe and mortality within any of the 4 subgroups defined by ejection fraction and atrial fibrillation type, although myocardial infarction, coronary artery bypass graft, and digoxin were significantly associated with death (estimated hazard ratios, 1.65, 1.59, and 1.62, respectively; P < 0.0001). ECVe were associated with increased cardiac hospitalization reported at the next follow-up visit (39.3% versus 5.8%; estimated odds ratio, 1.39; P < 0.0001). In the AFFIRM study, there was no significant association between ECVe and long-term mortality, even though ECVe were associated with increased hospitalizations from cardiac causes. Digoxin, myocardial infarction, and coronary artery bypass graft were significantly associated with mortality.
    Circulation Arrhythmia and Electrophysiology 04/2011; 4(4):465-9. DOI:10.1161/CIRCEP.110.960591 · 4.51 Impact Factor

  • Journal of Arrhythmia 01/2011; 27(Supplement):PE3_011. DOI:10.4020/jhrs.27.PE3_011
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    ABSTRACT: Introduction: Unfavourable Coronary sinus (CS) anatomy and lack of guide wire support make CRT implantation difficult in some cases. We describe a novel technique to obtain CS cannulation based on a combined use of an Amplatz guiding catheter and Quick cross support catheter to create a progressively supportive rail to advance the LV lead. Methods: The CS was cannulated with 6 Fr. Amplatz (AL2) guiding catheter and an exchange length 0.035 straight tip standard Terumo guide wire placed in distal CS. A 135 cm Spectranetics QuickCross support catheter (518 037, with a proximal shaft diameter of 4.8 Fr. tapering to a distal shaft diameter of 3.8 Fr.) was advanced through AL2 guiding over the Terumo guide wire into distal CS. Terumo guide wire was changed to 0.035 standard Jtip PTFE guide wire, keeping support catheter in place. The proximal luer fitting of support catheter was cut and a Medtronic inner sheath (ATTAIN SELECT II) advanced over support catheter into the mid CS. A 4 Fr. LV lead was advanced over 0.014PTCA wire through inner sheath after removal of support catheter and 0.035 guide wire. Conclusions: Support catheter can be used as anchor to facilitate CS cannulation and LV lead placement in patients with difficult venous anatomy.
    Journal of Arrhythmia 01/2011; 27(Supplement):PE4_087. DOI:10.4020/jhrs.27.PE4_087

Publication Stats

824 Citations
179.20 Total Impact Points


  • 2007-2015
    • National Heart Centre Singapore
      Tumasik, Singapore
  • 2007-2009
    • Cleveland Clinic
      • Center for Atrial Fibrillation
      Cleveland, Ohio, United States
  • 2008
    • Case Western Reserve University
      Cleveland, Ohio, United States