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Chu-Pak Lau

Publications and source records attributed to Chu-Pak Lau.

At least 55 records · Page 3Linked to original sources
PubMed2005

Area of left ventricular regional conduction delay and preserved myocardium predict responses to cardiac resynchronization therapy.

UNLABELLED: Cardiac resynchronization therapy. BACKGROUND: A significant proportion of patients with dilated cardiomyopathy and left bundle branch block (LBBB) do not respond to cardiac resynchronization therapy (CRT). The purpose of this study was to investigate whether the electromechanical properties of the myocardium would predict acute hemodynamic improvement during left ventricular (LV) pacing. METHODS AND RESULTS: We studied 10 patients with idiopathic dilated cardiomyopathy and LBBB (ejection fraction (EF): 27%+/-7%; QRS duration: 166+/-16 msec) using three-dimensional electromechanical endocardial mapping technique to assess endocardial activation time (Endo-AT), unipolar voltage, and local linear shortening during sinus rhythm. LV stimulation was performed in VDD mode at five different sites and three atrioventricular delays within the coronary sinus. LV+dP/dtmax changes from baseline were measured during LV stimulation at each site (%DeltadP/dtmax). There was no significant relationship between maximum %DeltadP/dtmax during LV stimulation at the best coronary sinus site and LV EF, baseline LV+dP/dtmax, total LV Endo-AT, baseline QRS duration nor changes in QRS duration during LV pacing. However, the maximum %DeltadP/dtmax was significantly positively correlated with percentage area of late Endo-AT (r=0.97, P<0.001) and preserved LV myocardium (r=0.81, P=0.005), respectively. Patients with >20% of LV area with late Endo-AT and >30% of preserved LV myocardium had five times better acute hemodynamic response with LV stimulation. Multivariate analysis showed that only percentage area of late Endo-AT was independently correlated with %DeltadP/dtmax (P<0.05). CONCLUSION: The presence of a larger amount of LV area with late Endo-AT and preserved LV myocardium measured by electromechanical mapping could identify patients who have better acute improvement in systolic performance during LV stimulation.

Aged↗
PubMed2005

Prevalence and predictors of new-onset atrial fibrillation after elective surgery for colorectal cancer.

There are only limited data on the prevalence and risk factors for postoperative atrial fibrillation (AF) after elective abdominal surgery. We retrospectively studied the clinical characteristics and hospital outcomes in 563 consecutive patients (mean age: 67 +/- 13 years, 245 men) with colorectal cancer who underwent elective colectomy. The baseline clinical characteristics of patients who underwent open (OC) versus laparoscopic colectomy (LC) were similar. Postoperative AF developed in 25 patients (4.4%). Patients who developed postoperative AF were older (P = 0.017), had a higher prevalence of hypertension (P = 0.05), more major postoperative events (P = 0.02), an elevated neutrophil count on postoperative day (POD) 1 (P = 0.007), longer hospitalizations (P = 0.02), and were more likely to undergo OC (P = 0.067). In multiple regression analysis, independent predictors of postoperative AF were OC (odd ratio: 3.3, 95% confidence interval: 1.3-8.0, P = 0.008), and an elevated neutrophil count on POD 1 (odd ratio: 3.2, 95% confidence interval: 1.3-7.8, P = 0.01). The incidence of postoperative AF after elective colorectal cancer surgery was approximately 4%. Postoperative AF was more commonly observed in patients with OC versus LC and in those with elevated postoperative neutrophil counts.

Aged↗
PubMed2005

Blood pressure response to transition from supine to standing posture using an orthostatic response algorithm.

Upon standing from a supine position, the normal response is an increase in heart rate to maintain blood pressure (BP). In patients with chronotropic incompetence, heart rate may not increase upon standing, and they may experience orthostatic hypotension (OH). We evaluated a new orthostatic response (OSR) pacing algorithm that uses an accelerometer signal to detect sudden activity following prolonged rest to trigger a 2 minutes increase in pacing rate to 94 bpm. Ten recipients of DDDR pacemakers which contain the OSR compensation algorithm (mean age = 77 +/- 9 years, 8 women) with sick sinus syndrome (n = 6) or atrioventricular block (n = 4) were studied. In all patients BP was measured before and 0.5, 1, 1.5, 2, and 3 minutes after standing at their programmed base rate. A 20 mmHg fall in systolic BP upon standing was observed in five patients (OH patients), while the other five were considered non-OH patients. The measurements were repeated with the OSR algorithm turned on. Mean BP was defined as 1/3 systolic BP + 2/3 diastolic BP. Baseline heart rate was significantly slower in OH patients (62 +/- 2 bpm) than non-OH patients (71 +/- 7 bpm, P < 0.05). In OH patients mean BP increased significantly upon standing (P < 0.05 for all comparisons) with the algorithm ON instead of decreasing with the algorithm OFF, at 1 minute (+3.4 vs -10.3 mmHg), 1.5 minutes (+7.0 vs -4.9 mmHg), 2 minutes (+1.6 vs -6.7 mmHg), and 3 minutes (+2.5 vs -8.5 mmHg). These preliminary results suggest that the OSR algorithm maintains BP upon standing in patients with OH.

Aged↗
PubMed2005

Impact of duration of cryothermal application on clinical efficacy of pulmonary vein isolation using transvenous cryoablation.

BACKGROUND: Recent studies have demonstrated that transvenous cryoablation is a safe and feasible method for pulmonary vein (PV) isolation for treatment of atrial fibrillation (AF). However, this technique is limited by a much longer ablation time than conventional radiofrequency ablation. The aim of this study was to determine the effect of duration of cryoablation application with double freeze-thaw cycles on clinical efficacy for PV isolation for treatment of AF. MATERIALS AND RESULTS: We compared the clinical efficacy and procedural time of cryoablation (CryoCorTM, San Diego, CA, USA) for segmental PV isolation in 30 patients (mean age 51 +/- 13, 20 men) with paroxysmal AF using either double 5-minute (n = 15) or double 2.5-minute (n = 15) freeze-thaw cycle delivered with a 10 F deflectable transvenous catheter. Clinical recurrence of AF and the occurrence of PV stenosis as determined by computer tomography of the thorax were performed at 3- and 12-month follow-up. Acute successful electrical isolation of PV was achieved with cryoablation in 96 of 98 (98%) targeted PVs in 30 patients (mean: 3.2 +/- 0.8 PVs per patient). There were no significant differences between the baseline characteristics, the number of PV isolated per patient, the total number and percentage of effective cryoablation and the acute clinical efficacy between using double 5-minute and double 2.5-minute freezes (P > 0.05). However, the fluoroscopy time (107 +/- 43 vs 138 +/- 113 minutes, P = 0.06) and the procedural time (360 +/- 113 vs 510 +/- 115 minutes, P = 0.01) of using double 2.5-minute freezes was reduced by approximately 30% compared with double 5-minute freezes. At a mean of 20 +/- 8 month follow-up, there was no significant difference in the chronic clinical efficacy of cryoablation in terms of freedom from AF in the absence of antiarrhythmic drug therapy between using double 5-minute (6/15, 40%) and double 2.5-minute freezes (7/15, 46%, P = 0.98). CONCLUSION: As compared with double 5-minute freeze, the use of a shorter double 2.5-minute freeze protocol significantly reduces the procedural time without affecting the acute and long-term clinical efficacy of cryoablation to isolate PV for treatment of AF.

Adult↗
PubMed2005

Successful pulmonary vein isolation using transvenous catheter cryoablation improves quality-of-life in patients with atrial fibrillation.

BACKGROUND: Recent studies have demonstrated that transvenous catheter cryoablation is a safe and effective technique for creating pulmonary veins (PVs) electrical isolation for the treatment of atrial fibrillation (AF). However, the impacts of this procedure on quality-of-life (QoL) have not been evaluated. METHODS AND RESULTS: We studied the effects of PV isolation using transvenous catheter cryoablation on QoL in 46 patients (34 men, mean age: 50 +/- 12 years) with drug-refractory AF. QoL was assessed by Medical Outcomes Study Short Form-36 (SF-36) and Symptom Checklist at baseline and 3-month after cryoablation, and compared with those in a sex-age matched normal control. At 3-month follow-up, 24 of 46 patients (52%) had no recurrence of AF, including 11 patients who were not taking antiarrhythmic drugs. At baseline, patients with AF had significantly lower QoL scores in overall and in 5/8 subscales of SF-36 than the sex-age matched control group (P < 0.05). In patients with successful outcome after cryoablation showed a significant improvement in overall and in 5/8 subscales of SF-36 QoL scores have significantly increased as compared with the baseline (P < 0.05). Furthermore, their QoL scores in overall and in 6/8 subscales of SF-36 were similar to the sex-age matched control group (P > 0.05). The Symptom Checklist also showed significant reduction in both the symptoms frequency scores and symptoms severity scores at 3-month follow-up as compared with baseline (P < 0.05). CONCLUSIONS: Successful PV isolation using transvenous catheter cryoablation is associated with significant reduction in the frequency and severity of AF symptoms and improvement in the general QoL, reaching the levels of normal controls.

Atrial Fibrillation↗
PubMed2005

Transvenous cryoablation reduces platelet activation during pulmonary vein ablation compared with radiofrequency energy in patients with atrial fibrillation.

BACKGROUND: Radiofrequency (RF) ablation procedures for atrial fibrillation (AF) are associated with potential risks of thromboembolism, which may be minimized by the use of cryoablation that preserves the integrity of endocardium. The objective of this study was to compare the thrombogenic potential of transvenous cryoablation versus RF ablation during pulmonary vein (PV) isolation. METHODS AND RESULTS: Thirty consecutive patients with paroxysmal AF were randomized to undergo segmental PV isolation procedure using 4-mm tip RF ablation (n = 15) or cryoablation (CryoCor, San Diego, CA, USA) (n = 15). Blood samples were drawn after sheath insertion (baseline), after transseptal puncture, before ablation (after heparin administration), and after isolation of a superior PV. Activation of coagulation was measured with plasma levels of prothrombin fragment 1 + 2 (F1 + 2) and thrombin-antithrombin III complex (TAT), and platelets by plasma level of beta-thromboglobulin (beta-TG) and flow cytometric enumerating of P-selectin (CD62)-positive platelets. In both groups, the plasma level of beta-TG, F1 + 2, and TAT were elevated after sheath insertion. The percentage changes in plasma level of beta-TG, F1 + 2, and TAT and CD41/62-positive platelets from baseline after transseptal puncture and before ablation were similar (P > 0.05). However, the percentage changes in CD62-positive platelets from baseline were significantly higher in patients treated with RF ablation (82 +/- 20%) than with cryoablation (22 +/- 14%, P = 0.02), although their plasma levels of beta-TG, F1 + 2, and TAT were not different (P > 0.05). CONCLUSIONS: Significant platelet and coagulation activations were observed during PV ablation procedures, and heparin administration only prevented activation of coagulation but not platelets. Persistent platelets activation was observed during RF energy application, but not during cryoablation.

Antithrombin III↗
PubMed2005

Characterization of ionic currents in human mesenchymal stem cells from bone marrow.

This study characterized functional ion channels in cultured undifferentiated human mesenchymal stem cells (hMSCs) from bone marrow with whole-cell patch clamp and reverse transcription polymerase chain reaction (RT-PCR) techniques. Three types of outward currents were found in hMSCs, including a noise-like rapidly activating outward current inhibited by the large conductance Ca(2+)-activated K(+) channel (I(KCa)) blocker iberiotoxin, a transient outward K(+) current (I(to)) suppressed by 4-aminopyridine (4-AP), and a delayed rectifier K(+) current (IK(DR))-like ether-à-go-go (eag) K(+) channel. In addition, tetrodotoxin-sensitive sodium current (I(Na.TTX)) and nifedipine-sensitive L-type Ca(2+) current (I(Ca.L)) were also detected in 29% and 15% hMSCs, respectively. Moreover, RT-PCR revealed the molecular evidence of high levels of mRNA for the functional ionic currents, including human MaxiK for I(KCa), Kv4.2 and Kv1.4 for I(to), heag1 for IK(DR), hNE-Na for I(Na.TTX), and CACNAIC for I(Ca.L). These results demonstrate that multiple functional ion channel currents--that is, I(KCa), I(to), heag1, I(Na.TTX), and I(Ca.L)--are expressed in hMSCs from bone marrow.

4-Aminopyridine↗
PubMed2005

A randomized, double-blind, placebo-controlled trial of abciximab for prevention of in-stent restenosis in diabetic patients after coronary stenting: results of the ASIAD (Abciximab in Stenting Inhibits restenosis Among Diabetics) Trial.

OBJECTIVES: Coronary stenting is associated with a high incidence of restenosis in patients with diabetes mellitus. Recent data suggest that diabetic patients treated with abciximab have a lower rate of target vessel revascularization (TVR). We sought to investigate whether abciximab can reduce in-stent restenosis after coronary stenting in diabetic patients. METHODS: In this prospective double-blind trial, we randomly assigned 254 patients with type 2 diabetes mellitus undergoing nonurgent coronary stenting to receive abciximab with an initial heparin bolus of 50 U/kg (n = 128) or placebo with an initial heparin bolus of 70 U/kg (n = 126). All patients received aspirin and clopidogrel before the procedure. The primary endpoint was angiographic restenosis by quantitative coronary angiography at 6 months. The secondary endpoint was death, myocardial infarction (MI), or target lesion revascularization (TLR) at 6 months. RESULTS: The clinical, angiographic, and procedural characteristics were matched between the 2 groups. Angiographic follow-up was completed in 226 patients (90%). Angiographic restenosis occurred in 29.1% of the abciximab group, and 24% of the placebo group (p = 0.30). The rates of the secondary endpoint were similar between the 2 groups (23.4% in the abciximab group versus 22.2% in the placebo group; p = 0.88). TLR was performed on 36 (18.4%) lesions in 29 (23.4%) patients of the abciximab group, and 26 (13.6%) lesions in 23 (18.3%) patients of the placebo groups, respectively (p = 0.21 and 0.35, respectively). CONCLUSIONS: Abciximab does not reduce angiographic restenosis or TLR in type 2 diabetic patients undergoing nonurgent coronary stenting.

Abciximab↗
PubMed2004

Effects of ventricular rate regularization pacing on quality of life and symptoms in patients with atrial fibrillation (Atrial fibrillation symptoms mediated by pacing to mean rates [AF SYMPTOMS study]).

The aim of this study was to investigate the effect of the Ventricular Response Pacing (VRP) algorithm, which regularizes ventricular rate during atrial fibrillation (AF), on symptoms, quality of life, and functional capacity. VRP regularizes the ventricular rate during AF without increasing the mean ventricular rate, thereby reducing the severity of AF-related symptoms in patients with persistent AF. However, VRP did not improve general quality of life (Medical Outcomes Study 36-item Short-Form General Health Survey), the performance of routine activities (Duke Activity Status Index), or functional capacity (hall walk) in patients with AF.

Aged↗
PubMed2004

Aspirin resistance is associated with a high incidence of myonecrosis after non-urgent percutaneous coronary intervention despite clopidogrel pretreatment.

OBJECTIVES: We sought to investigate the effect of aspirin resistance on the incidence of myonecrosis after non-urgent percutaneous coronary intervention (PCI) among patients pretreated with clopidogrel. BACKGROUND: Oral antiplatelet therapy using aspirin and a thienopyridine is the standard of care for preventing thrombotic complications of PCI. The effect of aspirin resistance on the outcomes of patients undergoing PCI is unknown. METHODS: We used the Ultegra Rapid Platelet Function Assay-ASA (Accumetrics Inc., San Diego, California) to determine aspirin responsiveness of 151 patients scheduled for non-urgent PCI. All patients received a 300-mg loading dose of clopidogrel >12 h before and a 75-mg maintenance dose in the morning of the PCI. The incidence of myonecrosis was measured by creatine kinase-myocardial band (CK-MB) and by troponin I (TnI) elevations after PCI. RESULTS: A total of 29 (19.2%) patients were noted to be aspirin-resistant. There was a significantly higher incidence of female subjects in the aspirin-resistant versus aspirin-sensitive groups. The incidence of any CK-MB elevation was 51.7% in aspirin-resistant patients and 24.6% in aspirin-sensitive patients (p = 0.006). Elevation of TnI was observed in 65.5% of aspirin-resistant patients and 38.5% of aspirin-sensitive patients (p = 0.012). Multivariate analysis revealed aspirin resistance (odds ratio [OR] 2.9; 95% confidence interval [CI] 1.2 to 6.9; p = 0.015) and bifurcation lesion (OR 2.8; 95% CI 1.3 to 6.0; p = 0.007) to be independent predictors of CK-MB elevation after PCI. CONCLUSIONS: Despite adequate pretreatment with clopidogrel, patients with aspirin resistance as measured by a point-of-care assay have an increased risk of myonecrosis following non-urgent PCI.

Aged↗
PubMed2004

Differential effects of tyrosine kinase inhibitors on volume-sensitive chloride current in human atrial myocytes: evidence for dual regulation by Src and EGFR kinases.

To determine whether protein tyrosine kinase (PTK) modulates volume-sensitive chloride current (I(Cl.vol)) in human atrial myocytes and to identify the PTKs involved, we studied the effects of broad-spectrum and selective PTK inhibitors and the protein tyrosine phosphatase (PTP) inhibitor orthovanadate (VO(4)(-3)). I(Cl.vol) evoked by hyposmotic bath solution (0.6-times isosmotic, 0.6T) was enhanced by genistein, a broad-spectrum PTK inhibitor, in a concentration-dependent manner (EC(50) = 22.4 microM); 100 microM genistein stimulated I(Cl.vol) by 122.4 +/- 10.6%. The genistein-stimulated current was inhibited by DIDS (4,4'-diisothiocyanostilbene-2,2'-disulfonic acid, 150 microM) and tamoxifen (20 microM), blockers of I(Cl.vol). Moreover, the current augmented by genistein was volume dependent; it was abolished by hyperosmotic shrinkage in 1.4T, and genistein did not activate Cl(-) current in 1T. In contrast to the stimulatory effects of genistein, 100 microM tyrphostin A23 (AG 18) and A25 (AG 82) inhibited I(Cl.vol) by 38.2 +/- 4.9% and 40.9 +/- 3.4%, respectively. The inactive analogs, daidzein and tyrphostin A63 (AG 43), did not alter I(Cl.vol). In addition, the PTP inhibitor VO(4)(-3) (1 mM) reduced I(Cl.vol) by 53.5 +/- 4.5% (IC(50) = 249.6 microM). Pretreatment with VO(4)(-3) antagonized genistein-induced augmentation and A23- or A25-induced suppression of I(Cl.vol). Furthermore, the selective Src-family PTK inhibitor PP2 (5 microM) stimulated I(Cl.vol), mimicking genistein, whereas the selective EGFR (ErbB-1) kinase inhibitor tyrphostin B56 (AG 556, 25 microM) reduced I(Cl.vol), mimicking A23 and A25. The effects of both PP2 and B56 also were substantially antagonized by pretreatment with VO(4)(-3). The results suggest that I(Cl.vol) is regulated in part by the balance between PTK and PTP activity. Regulation is complex, however. Src and EGFR kinases, distinct soluble and receptor-mediated PTK families, have opposing effects on I(Cl.vol), and multiple target proteins are likely to be involved.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗
PubMed2004

Clinical characteristics of and long-term outcome in Chinese patients with hypertrophic cardiomyopathy.

BACKGROUND: Data on the phenotypical pattern and natural history of hypertrophic cardiomyopathy in Chinese patients are very limited. The purpose of this study was to describe the clinical characteristics of and long-term outcome in Chinese patients with hypertrophic cardiomyopathy. METHODS: We evaluated 118 Chinese patients (62 male) who were diagnosed with hypertrophic cardiomyopathy at Queen Mary Hospital from 1973 to 2002. Diagnosis was based on the demonstration of left ventricular hypertrophy (wall thickness > or =15 mm during diastole), either in a specific region or with diffuse distribution, using echocardiography or magnetic resonance imaging. Clinical predictors of major cardiovascular events related to hypertrophic cardiomyopathy (cardiovascular death, potentially fatal cardiac arrhythmia, and refractory heart failure requiring cardiac transplantation or percutaneous alcohol septal ablation) were evaluated with univariate and multivariate Cox proportional hazards regression models. RESULTS: The mean (+/- SD) age at presentation was 54 +/- 18 years. During a mean follow-up of 5.8 +/- 4.3 years (range, 1 to 29 years) from presentation, major cardiovascular events related to hypertrophic cardiomyopathy occurred in 19 patients (16%), including 9 deaths. Annual cardiovascular mortality was 1.6%. Fifty-five patients (47%) had one or more cardiovascular complications related to hypertrophic cardiomyopathy, of which atrial fibrillation was the most common (35%, n = 41). The most common type of hypertrophic cardiomyopathy was the apical variant (41%, n = 49). In multivariate analysis, female sex was the only independent predictor of major cardiovascular events related to hypertrophic cardiomyopathy (hazard ratio = 5.86; 95% confidence interval: 1.77 to 7.21; P = 0.007). CONCLUSION: Hypertrophic cardiomyopathy in Chinese patients is characterized by late onset of presentation, a high incidence of the apical form of the condition, and adverse clinical outcome in female patients, which suggest a different phenotypical pattern than in white patients.

Adult↗
PubMed2004

Safety and feasibility of the use of a distal filter protection device in percutaneous revascularization of small coronary arteries.

The FilterWire EX is one of the filter protection devices developed as alternatives to balloon occlusion system for percutaneous coronary intervention. Its use has been recommended in vessels between 3.5 and 5.5 mm in diameter and no data are available on its use in smaller vessels. We evaluated the safety and feasibility of using FilterWire EX in native coronary arteries smaller than 3.5 mm. We successfully deployed and retrieved the FilterWire EX in 49 coronary arteries with a mean vessel diameter of 2.62 +/- 0.45 mm at device deployment. Reversible vasospasm was observed in 24 (50%) vessels, coronary flow was temporarily reduced in 22 (44.9%), and distal embolization was noted in 2 (4%). There was no vessel dissection induced by the device. These data suggest that it is safe and feasible to use the FilterWire EX in small coronary arteries.

Coronary Angiography↗
PubMed2004

Effect of a cardiac rehabilitation program on left ventricular diastolic function and its relationship to exercise capacity in patients with coronary heart disease: experience from a randomized, controlled study.

BACKGROUND: A cardiac rehabilitation and prevention program (CRPP) is a recognized nonpharmacological modality in the management of coronary heart disease (CHD). However, the effect of a CRPP on systolic function of the heart is controversial, and no data exists on diastolic function in CHD. A randomized, controlled study was conducted to address these issues. METHODS: Patients (n = 269) with recent acute myocardial infarction (n = 193) or after percutaneous coronary intervention (PCI) (n = 76) were randomized to either CRPP (2-hour twice-weekly exercise program for 8 weeks) or conventional therapy (control group). Serial treadmill exercise testing and at-rest echocardiography were performed during phases 1 (baseline), 2 (post-exercise training), and 3 (8-month follow up). RESULTS: The prevalence of left ventricular (LV) abnormal relaxation pattern (ARP) of diastolic dysfunction was increased in the control group only in phase 3 (65% vs 88%, chi2 = 7.6, P <.01). Significant improvement of individual LV diastolic parameters towards less severe delayed relaxation was also observed in the CRPP group, especially in those with recent acute myocardial infarction or ARP. The gain in exercise capacity was faster and more substantial in the CRPP than the control group (P <.001 for phase 2, P <.05 for phase 3), and was significantly correlated with LV diastolic indices in those with ARP. Exercise training had neutral effects on LV systolic function and rate-pressure product. CONCLUSIONS: In patients with CHD, CRPP prevented the progression of resting LV diastolic dysfunction, without affecting systolic function. In those with ARP, the improvement of diastolic function predicted the gain in exercise capacity.

Adult↗
PubMed2004

A short course of cardiac rehabilitation program is highly cost effective in improving long-term quality of life in patients with recent myocardial infarction or percutaneous coronary intervention.

OBJECTIVE: To evaluate the long-term effect of a cardiac rehabilitation and prevention program (CRPP) on quality of life (QOL) and its cost effectiveness. DESIGN: Prospective, randomized controlled trial. SETTING: University-affiliated outpatient cardiac rehabilitation and prevention center. PARTICIPANTS: A total of 269 patients (76% men; mean age, 64+/-11 y) with recent acute myocardial infarction (AMI; n=193) or after elective percutaneous coronary intervention (PCI; n=76) were randomized in a ratio of 2 to 1. INTERVENTION: Patients received either CRPP (an 8-wk exercise and education class in phase 2) or conventional therapy without exercise program (control group). They were followed until they had completed all 4 phases of the program (ie, 2 y). MAIN OUTCOME MEASURES: QOL assessments, by using the Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36) and Symptoms Questionnaire, were performed at the end of each phase. Direct health care cost was calculated, whereas cost utility was estimated as money spent (in US dollars) per quality-adjusted life-year (QALY) gained. RESULTS: In the CRPP group, 6 of the 8 SF-36 dimensions improved significantly by phase 2 and were maintained throughout the study period. Patients were less anxious and depressed, and felt more relaxed and contented. In the control group, none of the SF-36 dimensions were improved by phase 2, and bodily pain was increased. In phase 4, only 4 dimensions were improved. Symptoms were unchanged except for increased hostility score. There was a significant gain in net time trade-off in the CRPP group after phase 2. The direct health care expenses in the CRPP and control groups were 15,292 dollars and 15,707 dollars per patient, respectively. Therefore, the cost utility calculated was 640 dollars saved per QALY gained. Savings attributable to CRPP were primarily explained by the lower rate (13% vs 26% of patients, chi2 test=3.9, P <.05) and cost of subsequent PCI (P =.01). CONCLUSIONS: In an era of managing patients with coronary heart disease, a short-course CRPP was highly cost effective in providing better QOL to patients with recent AMI or after elective PCI. In addition, the improvement of QOL was quick and sustained for at least 2 years after CRPP.

Angioplasty, Balloon, Coronary↗
PubMed2004

Protein tyrosine kinase-dependent modulation of voltage-dependent potassium channels by genistein in rat cardiac ventricular myocytes.

Effects of the isoflavone protein tyrosine kinase (PTK) inhibitor genistein on voltage-dependent K(+) currents, i.e., transient outward K(+) current (I(to)), sustained K(+) current (I(ss)), and inward rectifier K(+) current (I(K1)) were studied in rat cardiac ventricular myocytes. It was found that I(to) was reversibly inhibited by genistein in a concentration-dependent manner (IC(50)=28.1 microM), while I(ss) was suppressed by genistein with IC(50) of 18.5 microM. In addition, I(K1) (at -50 mV) was significantly decreased by 36.3+/-4.4% with 25 microM genistein. The inhibition of I(to), I(ss), and I(K1) by genistein was significantly reversed by the application of the protein tyrosine phosphatase inhibitor sodium orthovanadate (1 mM). However, I(to), I(ss), and I(K1) were not affected by the non-isoflavone PTK inhibitor tyrphostin A23 (100 microM) and PP2 (1 microM). These results indicate that activation of I(to), I(ss), and I(K1) channels is modulated by genistein-sensitive PTKs in rat ventricular myocytes.

Animals↗
PubMed2004

Ionic current abnormalities associated with prolonged action potentials in cardiomyocytes from diseased human right ventricles.

OBJECTIVES: This study was designed to determine whether ionic currents in right ventricular myocytes from explanted human transplant recipient hearts are related to right ventricular histopathology and function. BACKGROUND: Cardiac action potential duration (APD) is prolonged in ventricular tissues/cells from patients with heart failure, but the ionic mechanisms are not well documented. METHODS: Membrane currents and transmembrane action potentials in myocytes from right ventricular epicardium of explanted human hearts were recorded using whole-cell patch clamp technique. Data from cells from right ventricles with severe histologic and functional abnormalities (abnormal histology group [AH]) and from right ventricles with preserved histology and function (relatively normal histology group [RNH]) were compared. RESULTS: We found that APD at 50% (APD(50)) and 90% repolarization (APD(90)) were significantly longer in AH cells than in RNH cells. Early afterdepolarizations (EADs) were observed in 20% of AH cells and none of the RNH cells. Inwardly rectifying K(+) current (I(K1)) was decreased (both inward and outward components). Both transient outward K(+) current (I(to1)) and slowly delayed rectifier K(+) current (I(Ks)) were down-regulated in AH cells. L-type Ca(2+) (I(Ca.L)) was not altered in AH cells. CONCLUSIONS: I(K1), I(to1), and I(Ks) are down-regulated in AH cells of human heart failure. This down-regulation contributes to APD prolongation that favors the occurrence of arrhythmogenic EADs and suggests a link between human cardiac histopathologic/functional abnormalities and arrhythmogenic ionic remodeling.

Action Potentials↗