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Your search keyword '"Yip, Gabriel W.K."' showing total 43 results
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43 results on '"Yip, Gabriel W.K."'

21. Severe obstructive sleep apnea is associated with left ventricular diastolic dysfunction *

Author

Fung, Jeffrey W.H., Li, Thomas S.T., Choy, Dominic K.L., Yip, Gabriel W.K., Ko, Fanny W.S., Sanderson, John E., and Hui, David S.C.

Subjects
Diastole (Cardiac cycle) -- Abnormalities -- Physiological aspects, Sleep apnea syndromes -- Physiological aspects, Health, Physiological aspects, Abnormalities
Abstract

Introduction: Hypertension is common in patients with obstructive sleep apnea (OSA). However, the effect of OSA on ventricular function, especially diastolic function, is not clear. Therefore, we have assessed the [...]

Published
2002

24. Does atrial fibrillation preclude biventricular pacing?

Author

Fung, Jeffrey W.H., Yip, Gabriel W.K., and Yu, Cheuk-Man

Subjects
Atrial fibrillation -- Complications and side effects, Heart failure -- Patient outcomes, Heart failure -- Development and progression, Heart failure -- Care and treatment, Electrophysiology -- Research, Cardiac pacing -- Usage, Cardiac pacing -- Patient outcomes, Health
Published
2008

39. Strain Rate Imaging Differentiates Transmural From Non-Transmural Myocardial Infarction A Validation Study Using Delayed-Enhancement Magnetic Resonance Imaging

Author

Zhang, Yan, Chan, Anna K.Y., Yu, Cheuk-Man, Yip, Gabriel W.K., Fung, Jeffrey W.H., Lam, Wynnie W.M., So, Nina M.C., Wang, Mei, Wu, Eugene B., Wong, John T., and Sanderson, John E.

Subjects
parasitic diseases, cardiovascular system, cardiovascular diseases
Abstract

ObjectivesThe 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).BackgroundIdentification of the transmural extent of myocardial necrosis and degree of non-viability after acute MI is clinically important.MethodsTissue 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.ResultsContrast-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 (−0.59 s−1detected a transmural infarction with high sensitivity (90.9%) and high specificity (96.4%), and −0.98 s−1>SRs >−1.26 s−1distinguished subendocardial infarction from normal myocardium with a sensitivity of 81.3% and a specificity of 83.3%.ConclusionsPeak 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.

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40. Diastolic and Systolic Asynchrony in Patients With Diastolic Heart Failure A Common But Ignored Condition

Author

Yu, Cheuk-Man, Zhang, Qing, Yip, Gabriel W.K., Lee, Pui-Wai, Kum, Leo C.C., Lam, Yat-Yin, and Fung, Jeffrey Wing-Hong

Abstract

ObjectivesThe 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.BackgroundFew data exist on mechanical asynchrony in DHF.MethodsTissue 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.ResultsBoth 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).ConclusionsDiastolic 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.

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43. Heart failure with a normal ejection fraction.

Author

Sanderson, John E. and Yip, Gabriel W.K.

Subjects
*HEART failure, *HEART conduction system, *HEART beat, HEART disease research
Abstract

The authors reflect on heart failure with a normal ejection fraction. They suggest that research has shown that heart failure with a normal ejection fraction is now a more common cause of hospital admission than systolic heart failure in many parts of the world. They argue that the condition is underdiagnosed, has a high mortality rate and lacks evidence based treatment.

Published
2009

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