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Cheuk-Man Yu

Publications and source records attributed to Cheuk-Man Yu.

At least 19 recordsLinked to original sources
PubMed2006

N-terminal pro-brain natriuretic peptide: an independent risk predictor of cardiovascular congestion, mortality, and adverse cardiovascular outcomes in chronic peritoneal dialysis patients.

This study was performed to determine whether the N-terminal pro-brain natriuretic peptide (NT-pro-BNP) is a useful biomarker in predicting cardiovascular congestion, mortality, and cardiovascular death and event in chronic peritoneal dialysis (PD) patients. A prospective cohort study was conducted in 230 chronic PD patients in a dialysis unit of a university teaching hospital. Serum NT-pro-BNP was measured at baseline together with echocardiography and dialysis indices. Each patient was followed for 3 yr from the day of enrollment or until death. Time to develop first episode of cardiovascular congestion and other cardiovascular event and time to mortality and cardiovascular death were studied in relation to NT-pro-BNP. NT-pro-BNP showed the strongest correlation with residual GFR, followed by left ventricular ejection fraction and left ventricular mass index. In the univariate Cox regression model, NT-pro-BNP was a significant predictor of cardiovascular congestion, mortality, and cardiovascular death and event. In the fully adjusted multivariable Cox regression analysis that included residual GFR, left ventricular ejection fraction, and left ventricular mass index, the hazard ratios for cardiovascular congestion, mortality, composite end point of mortality and cardiovascular congestion, and cardiovascular death and event for patients of the fourth quartile were 4.25 (95% confidence interval [CI] 1.56 to 11.62; P = 0.005), 4.97 (95% CI 1.35 to 18.28; P = 0.016), 5.03 (95% CI 2.07 to 12.26; P < 0.001), 7.50 (95% CI 1.36 to 41.39; P = 0.021), and 9.10 (95% CI 2.46 to 33.67; P = 0.001), respectively, compared with the first quartile. These data showed that NT-pro-BNP is an important risk predictor of cardiovascular congestion, mortality, and adverse cardiovascular outcomes in chronic PD patients and adds important prognostic information beyond that contributed by left ventricular hypertrophy, systolic dysfunction, and other conventional risk factors.

Adult↗
PubMed2006

Benefits of cardiac resynchronization therapy for heart failure patients with narrow QRS complexes and coexisting systolic asynchrony by echocardiography.

OBJECTIVES: This study was designed to evaluate the role of cardiac resynchronization therapy (CRT) in heart failure (HF) patients with narrow QRS complexes (<120 ms) and echocardiographic evidence of mechanical asynchrony. BACKGROUND: Cardiac resynchronization therapy is currently recommended to advanced HF patients with prolonged QRS duration. Echocardiographic assessment of systolic mechanical asynchrony has been proven useful to predict a favorable response after CRT. METHODS: A total of 102 HF patients with New York Heart Association (NYHA) functional class III or IV were enrolled. Among them, 51 had wide QRS (>120 ms) and 51 had narrow QRS (<120 ms). Tissue Doppler imaging (TDI) was employed to select patients with systolic asynchrony (increased asynchrony index) in the narrow-QRS group. Clinical and echocardiographic assessments were performed at baseline and 3 months after CRT. RESULTS: There was a significant reduction of left ventricular (LV) end-systolic volume in both narrow (122 +/- 42 cc vs. 103 +/- 47 cc, p < 0.001) and wide (148 +/- 74 cc vs. 112 +/- 64 cc, p < 0.001) QRS groups. Improvement of NYHA functional class (both p < 0.001), maximal exercise capacity (both p < 0.05), 6-min hall-walk distance (both p < 0.01), ejection fraction (both p < 0.001), and mitral regurgitation (both p < 0.005) was also observed. In both groups, the degree of baseline mechanical asynchrony determined LV reverse remodeling to a similar extent, as shown by the superimposed regression lines. Withholding CRT for 4 weeks resulted in loss of echocardiographic benefits. CONCLUSIONS: Cardiac resynchronization therapy for HF patients with narrow QRS complexes and coexisting mechanical asynchrony by TDI results in LV reverse remodeling and improvement of clinical status. The amplitude of benefit is similar to the wide-QRS group provided that similar extent of systolic asynchrony is selected.

Aged↗
PubMed2006

Diastolic and systolic asynchrony in patients with diastolic heart failure: a common but ignored condition.

OBJECTIVES: The present study aimed to examine whether diastolic and systolic asynchrony exist in diastolic heart failure (DHF) and their prevalence and relationship to systolic heart failure (SHF) patients. BACKGROUND: Few data exist on mechanical asynchrony in DHF. METHODS: Tissue Doppler echocardiography was performed in 373 heart failure patients (281 with SHF and 92 with DHF) and 100 normal subjects. Diastolic and systolic asynchrony was determined by measuring the standard deviation of time to peak myocardial systolic (Ts-SD) and peak early diastolic (Te-SD) velocity using a 6-basal, 6-mid-segmental model, respectively. RESULTS: Both heart failure groups had prolonged Te-SD (DHF vs. SHF vs. controls subjects: 32.2 +/- 18.0 ms vs. 38.0 +/- 25.2 ms vs. 19.5 +/- 7.1 ms) and Ts-SD (31.8 +/- 17.0 ms vs. 36.7 +/- 15.2 ms vs. 17.6 +/- 7.9 ms) compared with the control group (all p < 0.001 vs. control subjects). Based on normal values, the DHF group had comparable diastolic (35.9% vs. 43.1%; chi-square = 1.48, p = NS), but less systolic asynchrony than the SHF group (39.1% vs. 56.9%; chi-square = 8.82, p = 0.003). Normal synchrony, isolated systolic, isolated diastolic, and combined asynchrony were observed in 39.1%, 25.0%, 21.7%, and 14.1% of DHF patients, respectively, and these were 25.6%, 31.3%, 17.4%, and 25.6%, correspondingly, in SHF (chi-square = 10.01, p = 0.019). The correlation between systolic and diastolic asynchrony, and between the myocardial velocities and corresponding mechanical asynchrony appeared weak. A wide QRS duration (>120 ms) was rare in DHF (10.9% vs. 37.7% in SHF) (chi-square = 16.69, p < 0.001). CONCLUSIONS: Diastolic and/or systolic asynchrony was common in 61% of DHF patients despite narrow QRS complex. The presence of asynchrony was not related to myocardial systolic or diastolic function. Systolic and diastolic asynchrony were not tightly coupled, implying distinct mechanisms.

Aged↗
PubMed2006

Are left ventricular diastolic function and diastolic asynchrony important determinants of response to cardiac resynchronization therapy?

Cardiac resynchronization therapy (CRT) has been shown to reduce symptoms and reverse left ventricular (LV) remodeling. It is not known, however, whether diastolic function will improve after CRT and diastolic asynchrony will predict LV reverse remodeling. Seventy-six patients (mean age 65 +/- 12 years, 74% men) who received CRT were studied at baseline and after 3 months. Diastolic function was assessed by transmitral Doppler and tissue Doppler imaging. LV systolic and diastolic asynchrony were assessed by the time to peak myocardial contraction (Ts) and early diastolic relaxation (Te) using the 6 basal, 6 mid-segmental model. There were 42 responders (55%) with LV reverse remodeling (defined as a reduction of LV end-systolic volume >or=15%). Parameters of systolic function were significantly improved only in the responders. For diastolic function, there were reductions of transmitral E velocity in the 2 groups, without any change in atrial velocity or the E/A ratio. Tissue Doppler imaging revealed that myocardial early diastolic velocity was unchanged in responders but was significantly worsened in nonresponders. The systolic asynchrony index (the SD of Ts of 12 LV segments) correlated significantly with LV reverse remodeling (r = -0.64, p <0.001) but not the diastolic asynchrony index (the SD of Te of 12 LV segments) (r = -0.10, p = NS). The systolic asynchrony index was the only independent predictor of reverse remodeling (beta = -0.99, 95% confidence interval -1.41 to -0.58, p <0.001). In conclusion, CRT improves systolic function and systolic asynchrony but has a neutral effect on diastolic function and diastolic asynchrony. LV reverse remodeling response is determined by the severity of prepacing systolic asynchrony but not diastolic asynchrony or the diastolic filling pattern.

Aged↗
PubMed2006

Differential change in left ventricular mass and regional wall thickness after cardiac resynchronization therapy for heart failure.

AIMS: LV reverse remodelling has been shown to be a favourable response after cardiac resynchronization therapy (CRT) in many clinical trials. This study investigated whether left ventricular (LV) reverse remodelling after CRT has any structural benefit, which include the improvement of LV mass or regional wall thickness. METHODS AND RESULTS: Fifty patients (66 +/- 11 years) receiving CRT were followed up for at least 3 months. Echocardiography with tissue Doppler imaging was performed serially before and at day 1 and 3 months after CRT. Although LV end-systolic volume (LVESV) was decreased at day 1 after CRT (141 +/- 74 vs. 129 +/- 71 cm(3), P < 0.001), further LV reverse remodelling was observed at 3 months (110 +/- 67 cm(3), P < 0.001 vs. day 1). LV ejection fraction increased at day 1 (26.5 +/- 9.3 vs. 28.5 +/- 9.1%, P < 0.005) and was further improved at 3 months (34.2 +/- 10.5%, P < 0.001 vs. day 1). However, reduction of LV mass (231 +/- 67 vs. 213 +/- 59 g, P < 0.001) and regional wall thickness was only observed at 3 months, but not at day 1. The improvement of LV mass correlated with the change in LVESV (r = 0.66, P < 0.001) and the baseline systolic asynchrony index (Ts-SD) (r = -0.52, P < 0.001). LV mass was only decreased significantly in responders of LV reverse remodelling (245 +/- 66 vs. 207 +/- 61 g, P < 0.001), but increased in non-responders (209 +/- 64 vs. 223 +/- 56 g, P = 0.02). Responders had significant decrease in thickness of all the four walls for -6 to -11% (all P < or =0.02), whereas non-responders had increased thickness in septal and lateral walls for +11% (both P < 0.05). CONCLUSION: The acute reduction in LV volume after CRT is mediated by haemodynamic and geometric benefits without actual changes in LV mass. However, at 3-month follow-up, reduction in LV mass and regional wall thickness was demonstrated, which represents structural reverse remodelling. Such benefit was only observed in volumetric responders but was worsened in non-responders.

Aged↗
PubMed2006

Prevalence of amiodarone-related hepatotoxicity in 720 Chinese patients with or without baseline liver dysfunction.

BACKGROUND: The prevalence of hepatotoxicity after longterm oral amiodarone therapy in Chinese patients with or without elevated liver enzymes at baseline is unknown. HYPOTHESIS: Amiodarone may still be safely prescribed for Chinese patients who have baseline liver dysfunction. METHODS: This is a retrospective cross-sectional study. Significant liver dysfunction (SLD) was defined as alanine aminotransferase (ALT) > 2 times upper limit of normal range. RESULTS: Baseline liver function was checked in 628 of the 720 Chinese patients identified. The mean duration of amiodarone use was 615.9 +/- 703.1 days. Ninety patients (14.3%) had elevated baseline ALT. The prevalence of SLD was 3.7% (confidence interval [CI] 2.1-5.3%) and 4.4% (CI 0.2-8.6%) in patients with normal (n = 538) and elevated (n = 90) baseline ALT, respectively (p = 0.765). Therapy was continued in 42 patients with elevated baseline ALT until final follow-up. Eight of these (19.0%) had elevated ALT upon final follow-up, but the derangement was mild (mean ALT 134.8 +/- 145.9 IU/l, median 76 IU/l). During follow up, 24 patients developed SLD and half of these subsequently withdrew from therapy. The ALT levels at final follow-up had improved over time in both groups, but the mean difference was not significant (255.1 +/- 706.4 vs. 131.0 +/- 207.5 IU/l, p = 0.312). CONCLUSION: The prevalence of SLD in Chinese patients taking oral amiodarone with or without elevated baseline ALT was similar (4.4 vs. 3.7%). It seems that amiodarone may be safely prescribed in patients with elevated baseline ALT.

Alanine Transaminase↗
PubMed2006

Effect of age and heart rate on atrial mechanical function assessed by Doppler tissue imaging in healthy individuals.

BACKGROUND: The potential usefulness of Doppler tissue imaging (DTI) to assess atrial mechanical function in cardiac disease has been demonstrated. However, there are few reports on normal values of atrial function by DTI analysis. METHODS: Echocardiography with color-coded DTI was performed in 131 healthy control subjects. The peak atrial contraction velocity (V(A)) and the timing of mechanical events were assessed offline at the left atrial (LA) and right atrial (RA) free wall and interatrial septum. RESULTS: V(A) was higher in the RA (9.0 +/- 2.6 cm/s) than the LA (7.5 +/- 2.4 cm/s, P < .001), and both sites were higher than the interatrial septum (5.6 +/- 1.3 cm/s, both P < .001). The interatrial delay was 24 +/- 21 milliseconds. V(A) at the LA was higher in the participants aged 60 years or older than those who were younger than 60 years (8.1 +/- 2.7 vs 6.7 +/- 1.4 cm/s, P < .001), as was the velocity at the RA (9.6 +/- 2.8 vs 8.0 +/- 2.1 cm/s, P < .01). V(A) at the LA was higher in the participants with heart rate of 60/min or higher than those with lower heart rate (7.9 +/- 2.5 vs 6.8 +/- 1.8 cm/s, P < .05). Sex difference had no effect on V(A) and timings of atrial events. CONCLUSIONS: Assessment of atrial mechanical function by DTI is feasible in healthy individuals. The V(A) is the highest at the RA, followed by LA, and the lowest at the interatrial septum. Older age and faster heart rate seems to augment V(A) in the atrial walls.

Aging↗
PubMed2005

Cardiac resynchronization therapy: Part 1--issues before device implantation.

Cardiac resynchronization therapy (CRT) has been used extensively over the last years in the therapeutic management of patients with end-stage heart failure. Data from 4,017 patients have been published in eight large, randomized trials on CRT. Improvement in clinical end points (symptoms, exercise capacity, quality of life) and echocardiographic end points (systolic function, left ventricular size, mitral regurgitation) have been reported after CRT, with a reduction in hospitalizations for decompensated heart failure and an improvement in survival. However, individual results vary, and 20% to 30% of patients do not respond to CRT. At present, the selection criteria include severe heart failure (New York Heart Association functional class III or IV), left ventricular ejection fraction <35%, and wide QRS complex (>120 ms). Assessment of inter- and particularly intraventricular dyssynchrony as provided by echocardiography (predominantly tissue Doppler imaging techniques) may allow improved identification of potential responders to CRT. In this review a summary of the clinical and echocardiographic results of the large, randomized trials is provided, followed by an extensive overview on the currently available echocardiographic techniques for assessment of LV dyssynchrony. In addition, the value of LV scar tissue and venous anatomy for the selection of potential candidates for CRT are discussed.

Cardiac Output, Low↗
PubMed2005

Cardiac resynchronization therapy: Part 2--issues during and after device implantation and unresolved questions.

Encouraged by the clinical success of cardiac resynchronization therapy (CRT), the implantation rate has increased exponentially, although several limitations and unresolved issues of CRT have been identified. This review concerns issues that are encountered during implantation of CRT devices, including the role of electroanatomical mapping, whether CRT implantation should be accompanied by simultaneous atrioventricular nodal ablation in patients with atrial fibrillation, procedural complications, and when to consider surgical left ventricular lead positioning. Furthermore, (echocardiographic) CRT optimization and assessment of CRT benefits after implantation are highlighted. Also, controversial issues such as the potential value of CRT in patients with mild heart failure or narrow QRS complex are addressed. Finally, open questions concerning when to combine CRT with implantable cardioverter-defibrillator therapy and the cost-effectiveness of CRT are discussed.

Atrial Fibrillation↗
PubMed2005

Clinical versus echocardiographic parameters to assess response to cardiac resynchronization therapy.

Currently, a clear definition of response to cardiac resynchronization therapy (CRT) is still lacking, and clinical and echocardiographic end points are used. It is also unclear whether patients with clinical responses also improve in echocardiographic end points (and vice versa). To better understand and define response to CRT, the relation between improvement in clinical and echocardiographic parameters was evaluated in 144 patients.

Aged↗
PubMed2005

Tissue Doppler echocardiographic evidence of atrial mechanical dysfunction in coronary artery disease.

BACKGROUND: Atrial function is an integral part of cardiac function which is often neglected. The presence of coronary artery disease (CAD) may impair atrial function. This study investigated if atrial mechanical dysfunction was present in patients with CAD by tissue Doppler echocardiography (TDI). METHODS: Echocardiography with TDI was performed in 118 patients with CAD, and compared with 100 normal controls with comparable age and heart rate. Regional atrial function was assessed at the left (LA) and right (RA) atrial free wall and inter-atrial septum (IAS). The peak regional atrial contraction velocity of (V(A)) and the timing of mechanical events were compared. RESULTS: The V(A) in the LA (5.0+/-2.6 Vs 7.7+/-2.6 cm/s), IAS (4.8+/-1.7 Vs 5.7+/-1.5 cm/s) and RA (6.8+/-3.1 Vs 9.2+/-2.9 cm/s) were significantly decreased in patients with CAD when compared with controls (all p<0.001). Patients with impaired systolic function (ejection fraction 50% (both p<0.001); and were lower in those with restrictive filling pattern (RFP) than non-RFP of diastolic dysfunction (both p<0.05). The V(A) in all the subgroups was lower than controls. In contrast, transmitral atrial velocity was unable to reveal any abnormality except in the subgroup with a RFP. The LA dimension, area and volume were increased in the disease groups, but were largely unchanged in the RA despite abnormal V(A). The physiological inter-atrial delay for the onset and peak atrial contraction between the RA and LA were unaffected by CAD. CONCLUSIONS: The atrial contractile function in both atria was impaired in the presence of CAD, especially in the LA. This was detected even in patients with preserved systolic function or mild diastolic dysfunction such as non-RFP. Direct assessment of atrial velocity by TDI may better reflect atrial mechanical function than transmitral atrial velocity.

Atrial Function, Right↗
PubMed2005

Strain rate imaging differentiates transmural from non-transmural myocardial infarction: a validation study using delayed-enhancement magnetic resonance imaging.

OBJECTIVES: The aim of this study was to determine if strain rate imaging (SRI) correlates with the transmural extent of myocardial infarction (MI) measured by contrast-enhanced magnetic resonance imaging (Ce-MRI). BACKGROUND: Identification of the transmural extent of myocardial necrosis and degree of non-viability after acute MI is clinically important. METHODS: Tissue Doppler echocardiography with SRI and Ce-MRI were performed in 47 consecutive patients with a first acute MI between days 2 and 6 and compared to 60 age-matched healthy volunteers. Peak myocardial velocities and peak myocardial deformation strain rates were measured. Location and size of the infarct zone was confirmed by Ce-MRI using the delayed enhancement technique with a 16-segment model. RESULTS: Contrast-enhanced MRI identified transmural infarction in 21 patients, non-transmural infarction in 15 (mean transmurality of infarct 72.3 +/- 10.6%), and another 11 patients with subendocardial infarction (<50% transmural extent of the left ventricular wall). Peak systolic strain rate (SRs) of the transmural infarction segments was significantly lower compared to normal myocardium or with non-transmural infarction segments (both p < 0.0005). A cutoff value of SRs >-0.59 s(-1) detected a transmural infarction with high sensitivity (90.9%) and high specificity (96.4%), and -0.98 s(-1) >SRs >-1.26 s(-1) distinguished subendocardial infarction from normal myocardium with a sensitivity of 81.3% and a specificity of 83.3%. CONCLUSIONS: Peak myocardial deformation by SRI can differentiate transmural from non-transmural MI, and it allows noninvasive determination of transmurality of the scar after MI and thereby the extent of non-viable myocardium.

Acute Disease↗
PubMed2005

Left ventricular reverse remodeling but not clinical improvement predicts long-term survival after cardiac resynchronization therapy.

BACKGROUND: In patients with severe heart failure and dilated cardiomyopathy, cardiac resynchronization therapy (CRT) improves left ventricular (LV) systolic function associated with LV reverse remodeling and favorable 1-year survival. However, it is unknown whether LV reverse remodeling translates into a better long-term prognosis and what extent of reverse remodeling is clinically relevant, which were investigated in this study. METHODS AND RESULTS: Patients (n=141) with advanced heart failure (mean+/-SD age, 64+/-11 years; 73% men) who received CRT were followed up for a mean (+/-SD) of 695+/-491 days. The extent of reduction in LV end-systolic volume (LVESV) at 3 to 6 months relative to baseline was examined for its predictive value on long-term clinical outcome. The cutoff value for LV reverse remodeling in predicting mortality was derived from the receiver operating characteristic curve. Then the relation between potential predictors of mortality and heart failure hospitalizations were compared by Kaplan-Meier survival analysis, followed by Cox regression analysis. There were 22 (15.6%) deaths, mostly due to heart failure or sudden cardiac death. The receiver operating characteristic curve found that a reduction in LVESV of > or =9.5% had a sensitivity of 70% and specificity of 70% in predicting all-cause mortality and of 87% and 69%, respectively, for cardiovascular mortality. With this cutoff value, there were 87 (61.7%) responders to reverse remodeling. In Kaplan-Meier survival analysis, responders had significantly lower all-cause morality (6.9% versus 30.6%, log-rank chi2=13.26, P=0.0003), cardiovascular mortality (2.3% versus 24.1%, log-rank chi2=17.1, P<0.0001), and heart failure events (11.5% versus 33.3%, log-rank chi2=8.71, P=0.0032) than nonresponders. In the Cox regression analysis model, the change in LVESV was the single most important predictor of all-cause (beta=1.048, 95% confidence interval=1.019 to 1.078, P=0.001) and cardiovascular (beta=1.072, 95% confidence interval=1.033 to 1.112, P<0.001) mortality. Clinical parameters were unable to predict any outcome event. CONCLUSIONS: A reduction in LVESV of 10% signifies clinically relevant reverse remodeling, which is a strong predictor of lower long-term mortality and heart failure events. This study suggests that assessing volumetric changes after an intervention in patients with heart failure provides information predictive of natural history outcomes.

Aged↗
PubMed2005

Effects of cardiac resynchronization therapy on incidence of atrial fibrillation in patients with poor left ventricular systolic function.

Although the beneficial role of cardiac resynchronization therapy (CRT) in selected patients with heart failure is well proven, its effect on the incidence of atrial fibrillation (AF) is unclear. The present study compared the incidence of AF in 36 consecutive patients with chronic heart failure receiving CRT with its incidence in controls matched for age, gender, and left ventricular ejection fraction but not receiving CRT. The findings suggest that patients with CRT had a significantly lower incidence of AF than controls. Further studies to establish the role of CRT in preventing AF and its mechanisms are warranted.

Aged↗