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Gregory Y H Lip

Publications and source records attributed to Gregory Y H Lip.

At least 19 recordsLinked to original sources
PubMed2026

Combined effects of early rhythm control and exercise on atrial fibrillation outcomes: Nationwide cohort analysis.

BACKGROUND: The benefit of combining early rhythm control (ERC) and exercise habit change in atrial fibrillation (AF) is unknown. OBJECTIVE: To evaluate the primary outcomes-including major adverse cardiovascular events (MACE) and all-cause death-according to the combination of ERC status and exercise habit change. METHODS: From the National Health Information Database, we included 161,379 patients diagnosed with AF. Rhythm control initiated within 2 years from AF diagnosis was defined as ERC. Based on the status of regular exercise at serial health examinations before and after AF diagnosis, exercise habit change was categorized into persistent non-exercisers, exercise dropouts, new exercisers, and exercise maintainers. RESULTS: During a mean follow-up of 4.6 years, ERC was associated with a lower risk of MACE and all-cause death, with adjusted hazard ratios (aHRs) of 0.832 (95% confidence interval [CI], 0.797-0.868) and 0.953 (95% CI, 0.915-0.992), respectively (both P < .001). Exercise maintenance was also associated with a lower risk of MACE and all-cause death (aHR = 0.822; 95% CI, 0.763-0.886 for MACE and 0.708; 95% CI, 0.658-0.762 for all-cause death; both P < .001). There was a progressive decrease in the risk of MACE and all-cause death as patients with AF engaged in ERC or regular exercise; the combination of ERC and exercise maintenance provided the greatest benefit, associated with the lowest risk of MACE (aHR = 0.641; 95% CI, 0.576-0.713) and all-cause death (aHR = 0.564; 95% CI, 0.499-0.636; both P < .001). CONCLUSION: The combination of ERC and exercise maintenance yielded a synergistic effect, maximizing the reduction in MACE and all-cause death risks, highlighting the importance of integrated management in AF.

Atrial fibrillation↗
PubMed2006

Blood oxygen saturation during atrio-ventricular dissociation with wide-QRS complex tachycardias.

Amplitude ratios of two adjacent mixed blood oxygen saturation curve peaks in randomly selected strips of ECG were analysed in 32 patients with regular wide-QRS complex tachycardias and 60 control subjects where pacing was performed before ablation of narrow-QRS complex tachycardias. Patients with VT showed different patterns of A-to-V relationships, leading to varying ratios of SpO2 adjacent peak amplitudes, in contrast to patients with aberrant SVTs and 1:1 AV association. Application of a criterion of adjacent SpO2 peaks differing by twofold or more had a sensitivity of 90.0% and specificity of 83.3% to detect AV dissociation during VT. Fluctuations on the mixed oxygen saturation curve may be a useful non-invasive clinical parameter to detect different ventricular filling caused by atrio-ventricular dissociation during VT.

Case-Control Studies↗
PubMed2005

Diabetes mellitus and atrial fibrillation: perspectives on epidemiological and pathophysiological links.

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia, which is also associated with a substantial risk of mortality and morbidity from stroke, thromboembolism, heart failure and hospitalisations. On a epidemiological basis, diabetes mellitus is commonly associated with AF. Nonetheless, AF is also associated with vascular disease and hypertension, which are themselves intimately linked to diabetes. Indeed, the precise pathophysiological and clinical relationships between AF and diabetes mellitus are not completely understood. What we do know is that both diabetes and AF are individually bad for our patients, and the presence of both requires aggressive management strategies.

Atrial Fibrillation↗
PubMed2005

Inter-relationships of indices of endothelial damage/dysfunction [circulating endothelial cells, von Willebrand factor and flow-mediated dilatation] to tissue factor and interleukin-6 in acute coronary syndromes.

BACKGROUND: Increased circulating endothelial cells (CECs, reflecting endothelial damage) in acute coronary syndromes (ACS) has been reported. However, the inter-relationships of indices of endothelial damage/injury with development of vascular (dys)function, plasma levels of tissue factor (TF, an index of coagulation) and interleukin-6 (IL-6, a pro-inflammatory cytokine) have not been investigated in ACS. We hypothesized that increased CECs can be related to impaired flow-mediated vasodilatation (FMD, an index of endothelial dysfunction) and elevated plasma von Willebrand factor (vWf, also marking endothelial damage/dysfunction), TF and IL-6 in patients with ACS. METHODS: We studied 120 patients with ACS (80 acute myocardial infarction and 40 unstable angina; 86 male, age 65+/-12 years) and 40 matched patients with stable CAD and 40 healthy controls (HC) in a cross-sectional analysis. Plasma vWf, TF and IL-6 levels were measured by ELISA. CECs were quantified using epifluorescence microscope after immunomagnetic separation with CD146. Brachial artery FMD was assessed in a subset of 39 ACS patients. RESULTS: ACS patients had significantly higher CECs, vWf, TF and IL-6 levels, but lower FMD, when compared to stable CAD and HC (all p<0.001) and all were inter-correlated significantly. In ACS, CECs was strongly correlated with FMD (r=-0.64, p<0.001) and TF (r=0.7, p<0.001). In stable CAD, significant correlations were again found between many indices, but on multivariate analysis, IL-6 and vWf were both independently related to FMD. CONCLUSIONS: Increased CECs in ACS patients are closely associated with endothelial damage/dysfunction (vWf and FMD), coagulation (TF) and inflammation (IL-6). These inter-relationships support the concept of a central role of endothelial damage/injury in the activation of vascular and coagulation abnormalities in ACS.

Aged↗
PubMed2005

Home-based cardiac rehabilitation compared with centre-based rehabilitation and usual care: a systematic review and meta-analysis.

BACKGROUND: To determine the effectiveness of home-based cardiac rehabilitation programmes compared with (i) usual care and (ii) supervised centre-based cardiac rehabilitation on mortality, health related quality of life and modifiable cardiac risk factors of patients with coronary heart disease. METHODS: Systematic review and meta-analysis of randomised controlled trials. MAIN OUTCOME MEASURES: mortality, smoking cessation, exercise capacity, systolic blood pressure, total cholesterol, psychological status, and health related quality of life. RESULTS: Eighteen included trials for home versus usual rehabilitation and six trials of home versus supervised centre-based rehabilitation were identified. The home-based interventions were clinically heterogeneous, trials often small, with quality poorly reported. Compared with usual care, home-based cardiac rehabilitation had a 4 mm Hg (95% CI 6.5, 1.5) greater reduction in systolic blood pressure, and a reduced relative risk of being a smoker at follow-up (RR 0.71, 95% CI 0.51, 1.00). Differences in exercise capacity, total cholesterol, anxiety and depression were all in favour of the home-based group. In patients post-myocardial infarction exercise capacity was significantly improved in the home rehabilitation group by 1.1 METS (95% CI 0.2, 2.1) compared to usual care. The comparison of home-based with supervised centre-based cardiac rehabilitation revealed no significant differences in exercise capacity, systolic blood pressure and total cholesterol. CONCLUSIONS: Current evidence does not show home-based cardiac rehabilitation to be significantly inferior to centre-based rehabilitation for low-risk cardiac patients. However, the numbers of patients included are less than 750 and ongoing trials will contribute to the debate on the acceptability, effectiveness and cost-effectiveness of home-based cardiac rehabilitation.

Cardiology Service, Hospital↗
PubMed2005

The effects of direct current cardioversion for persistent atrial fibrillation on indices of endothelial damage/dysfunction.

BACKGROUND: Atrial fibrillation is associated with increased thromboembolic risk, and this risk may occur even following cardioversion. Atrial fibrillation has been hypothesised to cause alterations in endothelial cell function through the influences of altered flow dynamics, and resultant endothelial dysfunction may be contributory to the generation of a prothrombotic state. The aim of this study was therefore to assess endothelial function before and after electrical cardioversion. METHODS: We studied 30 consecutive patients undergoing elective cardioversion for AF and compared them with 20 healthy controls. Plasma levels of endothelial damage/dysfunction [von Willebrand factor (vWF), E-selectin (E-sel), soluble thrombomodulin (sTM)] and Circulating Endothelial Cells (CECs, an index of endothelial damage) in whole blood were measured in all subjects and on the AF group at baseline (pre-cardioversion) and at 2 h and 4 weeks following cardioversion. RESULTS: Plasma levels of vWf were significantly increased in persistent AF at baseline compared to healthy controls (p<0.001). With restoration of sinus rhythm, vWF levels were significantly decreased at 4 weeks (p=0.0001), whilst levels of CECs (p=0.01) and sTM (p=0.022), although not increased at baseline, were significantly increased following cardioversion. CONCLUSION: Although plasma vWF levels decreased post-cardioversion, suggesting some improvement in vascular endothelial function, the increases in sTM and CECs at 4 weeks may indicate endothelial injury sustained peri-cardioversion. This (delayed) injury and shedding of endothelial cells post-cardioversion may contribute to late thromboembolic risk.

Aged↗
PubMed2005

Is atrial fibrillation an inflammatory disorder?

There is mounting evidence to support the influence of inflammation in the pathogenesis of atrial fibrillation (AF). Indeed, AF is associated with increased levels of known inflammatory markers, even after adjustment for confounding factors. The renin-angiotensin-aldosterone system (RAAS) appears to play a key role in this process. Atrial biopsies from patients with AF have also confirmed the presence of inflammation. Furthermore, there is preliminary evidence to support a number of drug therapies that have the potential to reduce the clinical burden of AF. In this review, we present an overview of the evidence supporting a link between inflammation and AF, and some of the drug therapies, such as the angiotensin-converting enzyme inhibitors, angiotensin II receptor blockers, steroids, fish oils, and vitamin C, that might be efficacious in the prevention of AF by modulating inflammatory pathways.

Ascorbic Acid↗
PubMed2005

Statins and postoperative risk of atrial fibrillation following coronary artery bypass grafting.

Atrial fibrillation (AF) is a common complication after coronary artery bypass grafting. Atrial remodeling has been observed in AF and has been associated with the development of this arrhythmia. Because 3-hydroxy-3-methylglutaryl coenzyme A inhibitors (statins) have been demonstrated to modify remodeling, we hypothesized a protective role of statins against postoperative AF. We also hypothesized that extracellular matrix turnover and brain natriuretic peptide (BNP) might be related to such atrial remodeling. We studied 234 consecutive patients who underwent coronary artery bypass grafting (173 men; 65 +/- 9 years of age) in whom the occurrence of postoperative AF was monitored. In a subgroup of 66 patients, we measured plasma levels of matrix metalloproteinase-1 (MMP-1), its inhibitor, tissue inhibitor matrix metalloproteinase-1 (TIMP-1; as indexes of extracellular matrix remodeling), and N-terminus pro-BNP (related to left ventricular function) at baseline and at 24 hours after surgery. Of 234 patients, 66 (28.2%) developed postoperative AF. In multivariate analysis, previous AF was related to an increase in the development of AF (odds ratio 11.92, 95% confidence interval 2.37 to 59.98, p = 0.026), whereas statin use was related to a decrease in arrhythmia (odds ratio 0.52, 95% confidence interval 0.28 to 0.96, p = 0.038). A higher TIMP-1/MMP-1 ratio at 24 hours after surgery was present in those who did not develop postoperative AF (p = 0.043). Statin use was associated with increased TIMP-1 levels and TIMP-1/MMP-1 ratio (p = 0.027 and 0.036, respectively). No significant relations to N-terminus pro-BNP were seen. In conclusion, previous AF and nonuse of statins are significantly associated with AF after coronary artery bypass grafting. Statin use may be protective against AF after coronary artery bypass grafting, possibly due to alterations in the extracellular matrix and remodeling after coronary artery bypass grafting.

Aged↗
PubMed2005

Patient knowledge and perceptions of atrial fibrillation and anticoagulant therapy: effects of an educational intervention programme. The West Birmingham Atrial Fibrillation Project.

OBJECTIVE: Previous research has demonstrated that patients with atrial fibrillation (AF) possess very little knowledge of their disease, the consequences of AF and the benefits/risks of anti-coagulant therapy. The aim of this pilot study was to examine patient's knowledge and perceptions of AF and their anticoagulant treatment before and after a brief educational intervention. MATERIALS AND METHODS: Ninety-three patients (47 male; mean (S.D.) age 67.3 (11.6) years) completed the baseline interview to assess their knowledge and perceptions of AF. All patients were given an information booklet which explained what AF was, associated symptoms, the possible causes and consequences of AF, treatment options and their benefits/risks, what the INR is and what factors may effect it. The booklet was explained to each patient by the researcher and given to the patient to take away for reference. Thirty-three (35.5%) patients (12 men; mean (S.D.) age 68.0 (13.6) years) completed the follow-up assessment to re-assess their knowledge and perceptions of AF. RESULTS: Only 49% of patients could name their cardiac condition at baseline, although the majority were aware that AF was an arrhythmia (80% baseline vs. 91% follow-up). Only about half the patients perceived AF as a serious condition or were aware that AF predisposes to thromboembolism at baseline. Following the educational intervention there was a non-significant increase in patient knowledge of the risks associated with AF. Of those who completed both questionnaires, 52% were aware that anticoagulants prevented blood clots, which increased to 70% post-intervention. However, few patients were aware of the benefit of stroke prevention associated with anticoagulants at baseline (21%) or after the educational intervention (27%). The intervention had little effect on increasing awareness of the bleeding risks associated with anticoagulants, although three in five people appeared to appreciate these risks. However, the educational intervention significantly improved patient's knowledge of the target INR range and factors that may affect INR levels (p=0.001 and p=0.014, respectively) for those who completed both questionnaires. CONCLUSIONS: Most patients with AF possess very limited knowledge about their cardiac condition, its consequences, and how anticoagulant treatment can benefit them. This pilot study has demonstrated that a brief educational intervention with an information booklet can help to somewhat improve their knowledge about anticoagulation therapy for AF.

Aged↗
PubMed2005

Rheumatoid disease and ischaemic heart disease: insights from pathophysiology and vascular biology.

Rheumatoid disease (RD) is a multisystem inflammatory disorder, which is associated with an increased cardiovascular mortality, thought to be due to ischaemic heart disease (IHD). The precise mechanisms causing increased IHD in RD are unclear. However, there is increasing recognition that atherosclerosis is another chronic inflammatory condition, which shares several pathophysiological features with RD. For example, endothelial damage/dysfunction, platelet activation, hypercoagulability and angiogenesis are well-recognised in both disease processes. Furthermore, RD may influence traditional risk factors such as dyslipidaemia. Although the exact reasons for the increased ischaemic burden are unclear, physicians should place a high priority upon reducing cardiovascular risk in sufferers of RD. This review summarises factors that might contribute to the pathogenesis of IHD in RD. Discussion will focus upon features shared by atherosclerotic and rheumatoid processes, as well as possible interactions between RD and conventional IHD risk factors.

Cell Adhesion Molecules↗
PubMed2005

Stroke prevention with aspirin, warfarin and ximelagatran in patients with non-valvular atrial fibrillation: a systematic review and meta-analysis.

OBJECTIVE: To compare the effectiveness of aspirin, warfarin, and ximelagatran as thromboprophylaxis in patients with non-valvular atrial fibrillation (NVAF). METHODS: Systematic review of randomised controlled trials in patients with NVAF treated with adjusted-dose warfarin and aspirin, fixed low-dose (FLD) warfarin, ximelagatran or placebo. Outcome measures studied were ischaemic stroke, systemic embolism, mortality and haemorrhage. Meta-analysis was performed using a fixed effects model. RESULTS: We identified 13 trials (n=14,423 participants) of sufficient quality to be included in the analysis. Adjusted-dose warfarin significantly reduced the risk of ischaemic stroke or systemic embolism compared with aspirin (relative risk [RR] 0.59; 95% confidence interval [CI]: 0.40 to 0.86), FLD warfarin (RR 0.36; 95% CI: 0.23 to 0.58), or placebo (RR 0.33; 95% CI: 0.24 to 0.45). However, aspirin and placebo had a lower risk of major bleeding compared to warfarin (RR 0.58; 95% CI: 0.35 to 0.97 and RR 0.45; 95% CI: 0.25 to 0.82, respectively). The oral direct thrombin inhibitor, ximelagatran was as effective as adjusted-dose warfarin in the prevention of ischaemic strokes or systemic emboli (RR 1.04; 95% CI: 0.77 to 1.40) with less risk of major bleeding (RR 0.74; 95% CI: 0.56 to 0.96). Adjusted-dose warfarin significantly reduced mortality compared to placebo (RR 0.69; 95% CI: 0.53 to 0.89), but not for any of the other comparisons (aspirin: RR 0.87; 95% CI: 0.67 to 1.13; FLD warfarin: RR 1.11; 95% CI: 0.81 to 1.52; ximelagatran: RR 1.04; 95% CI: 0.86 to 1.26). CONCLUSIONS: We have extended previous analyses, making this the largest systematic review and meta-analysis of thromboprophylaxis trial data in AF--and have included recent trials with the new oral direct thrombin inhibitor, ximelagatran. This systematic review confirms the superiority of anticoagulation therapy over aspirin as thromboprophylaxis in patients with NVAF. The new oral direct thrombin inhibitor, ximelagatran, appears as effective as adjusted-dose warfarin for the prevention of thromboembolic events in NVAF, with a lower risk of bleeding.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed2005

Increased circulating endothelial cells in acute heart failure: comparison with von Willebrand factor and soluble E-selectin.

BACKGROUND: Circulating endothelial cells (CECs) in the peripheral blood, probably representing the most direct evidence of endothelial cell damage, are increased in myocardial infarction, unstable angina and critical limb ischaemia. As chronic heart failure is also associated with endothelial abnormalities, we hypothesised that CECs are raised in acute heart failure and that they would correlate with plasma indices of endothelial perturbation, that is, von Willebrand factor (vWf) and soluble E-selectin. METHODS: We studied 30 patients with acute heart failure (venesected within 24 h of emergency hospital admission), 30 patients with chronic stable heart failure (venesected as out-patients, all patients in sinus rhythm with ejection fraction < or = 40%) and 20 healthy controls. CECs were quantified using epifluorescence microscopy after CD146-immunomagnetic separation and phenotyped by streptavidin/biotin immunocytochemistry. Citrated plasma was analysed for soluble E-selectin and vWf by ELISA. RESULTS: Levels of CECs, vWf and soluble E-selectin were significantly higher (all p<0.01) in patients with heart failure compared to controls, with no significant differences between acute and chronic heart failure. CECs correlated with plasma vWf (p<0.0001) and soluble E-selectin (p = 0.022) but not ejection fraction or NYHA class. In multiple regression analysis, heart failure was the only independent predictor of raised CECs (p<0.0001). Immunoperoxidase-defined surface expression of CD34, CD45 and CD36 by CECs was <2%, 0% and 8%, respectively. CONCLUSION: CECs, a possibly heterologous population, may be used as a novel measure of endothelial damage in acute heart failure and may have implications for the thrombotic risk associated with acute and chronic heart failure and prognosis in this condition.

Acute Disease↗
PubMed2005

Effects of omega-3 polyunsaturated fatty acids on plasma indices of thrombogenesis and inflammation in patients post-myocardial infarction.

OBJECTIVE: To determine the effects of n-3 PUFAs supplementation on plasma indices of coagulation (fibrinogen), fibrin D-Dimer (an index of thrombogenesis and fibrin turnover), endothelial damage/dysfunction (von Willebrand factor (vWf)), platelet activation (soluble P-selectin (sP-sel)) and inflammation (interleukin-6, IL-6) in patients following acute myocardial infarction. METHODS: Open-labelled randomised controlled trial. Seventy-seven post-myocardial infarction (MI) patients stabilized on standard secondary prevention therapy were randomised either to 3 months' treatment with Omacor 1 g/day (n=37) or 'usual care' control (n=40). Plasma levels of fibrinogen, D-Dimer, vWf, sP-sel, IL-6 and plasma viscosity at baseline and after 3 months were determined. RESULTS: At baseline, there were no significant differences between the groups in all research indices, except vWf levels were higher in patients allocated to Omacor supplementation. After 3 months, there were no significant changes in the levels of any research indices in either the Omacor supplemented or the 'usual care' control patients when compared to baseline. Patients who received Omacor experienced a fall in total cholesterol (p=0.019), total/HDL-cholesterol ratio (p=0.009) and LDL-cholesterol (p=0.023). However, the relative changes in plasma lipids and lipoproteins did not differ between the two groups. CONCLUSIONS: Three-month supplementation of Omacor at 1 g per day in post-MI patients is not associated with an improvement in the levels of peripheral indices of coagulation potential, endothelial function, platelet reactivity and inflammation.

Dietary Supplements↗