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Biomedical subjects

Tsung-Hsien Lin

Publications and source records attributed to Tsung-Hsien Lin.

At least 19 recordsLinked to original sources
PubMed2007

Effect of preload alterations by hemodialysis on the time interval between the onsets of early diastolic mitral inflow and annular waveforms.

BACKGROUND: The T(Ea-E), which is defined as the time interval between the peak of the R-wave and the onset of early diastolic mitral annular waveform (T(Ea)) minus the time interval between the peak of the R-wave and the onset of early diastolic mitral inflow waveform (T(E)), is recently proposed as a useful index of left ventricular (LV) relaxation. The aim of this study is to determine whether the T(Ea-E) is preload-independent. METHODS: Twenty hemodialysis (HD) patients (9 men; age 64 +/- 9 years) underwent echocardiography 1 hour before and 1 hour after HD was studied. RESULTS: After HD, the body weight (P < 0.001), early transmitral filling wave peak velocity (E) (P < 0.001), the ratio of E to late transmitral filling wave peak velocity (P = 0.011), the early diastolic mitral anuular velocity (Ea) (P = 0.002), E/Ea (P = 0.026), and T(Ea-E) (P < 0.001) decreased significantly, and the T(Ea) (P = 0.047) and T(E) (P = 0.005) increased significantly. In addition, T(Ea-E) had a significant negative correlation with Ea either before (r =-0.457, P = 0.043) or after HD (r =-0.637, P = 0.003). CONCLUSIONS: T(Ea-E), as well as Ea, was a preload-dependent relaxation index. The preload dependence of this newer Doppler parameter limited its utility in evaluating LV diastolic function in HD patients.

Aged↗
PubMed2007

D-allele of ACE polymorphism is associated with increased magnitude of QT dispersion prolongation in elderly Chinese: 4-year follow-up study.

BACKGROUND: There has not been a longitudinal investigation of the influence of angiotensin-converting enzyme (ACE) insertion/deletion and angiotensinogen (AGT) M235T gene polymorphisms on repolarization parameters, such as QT dispersion (QTd) and the peak and the end of the T-wave interval (Tpe). METHODS AND RESULTS: Electrocardiographys were recorded from 106 elderly Chinese at baseline, and 2nd and 4th year follow-up. The corrected QT (QTc), QTd, QTc dispersion (QTcd) and Tpe were manually calculated. Average age was 72.7+/-4.1 years (range 62-81). QTd, QTcd and Tpe were significantly prolonged (all p<0.001 at the 2nd and 4th year). At the 4th year the magnitude of the QTd prolongation, but not Tpe, was significantly higher in subjects carrying the ACE D allele than non-D-allele carriers (p=0.001), as was QTcd (p=0.002). This association was still significant in the multivariate analyses (p<0.001 and p=0.001 for QTc and QTcd, respectively). No significant correlation was found between repolarization parameters and AGT genotype. CONCLUSIONS: This longitudinal study shows that the ageing process is associated with prolongation of QTd, QTcd and Tpe after 4 years follow-up. The elderly Chinese subjects with the ACE D-allele had greater prolongation QTd and QTcd.

Aged↗
PubMed2006

Effects of verapamil on superior vena cava electrical remodeling induced by short-term pacing from right atrium and superior vena cava in human.

BACKGROUND: Although the superior vena cava (SVC) may be involved in the triggering or maintenance of atrial fibrillation (AF), the electrophysiological properties of SVC in human are ill-defined. METHODS: The baseline effective refractory periods (ERPs) of high right atrium (HRA), SVC and the conduction time (CT) between HRA and SVC were measured at pacing cycle lengths (PCL) of 600 and 400 ms respectively in 20 patients (12 females, age 46+/-13 years) with paroxysmal supraventricular tachycardia. Immediately after acute electrical remodeling (ER) induced by constant HRA or SVC pacing at PCL of 400 ms for 5 min, ERPs of HRA, SVC and the CT between HRA and SVC were determined. After verapamil was administered, the same protocols for determining ERPs of HRA, SVC and the CT between HRA and SVC were repeated. RESULTS: The baseline ERP of SVC was significantly longer than that of HRA. The CT from SVC to HRA was significantly longer than that from HRA to SVC. After acute ER, both the ERPs of HRA and SVC were significantly shortened. However, no significant changes of the CT between HRA and SVC could be demonstrated. After verapamil infusion, significant shortening of the ERP of HRA and SVC still occurred following acute ER and the ERP of SVC was still longer than that of HRA. CONCLUSIONS: In human, ER can occur both in HRA and SVC after a short and moderately rapid heart rate pacing either from HRA or SVC. Verapamil cannot prevent such ER from occurring.

Calcium Channel Blockers↗
PubMed2006

Usefulness of time interval between end of diastolic mitral annular velocity pattern and onset of QRS for predicting left ventricular end-diastolic pressure.

Diastolic mitral annular motion may terminate earlier in patients with higher left ventricular end-diastolic pressure (LVEDP). It was therefore hypothesized that the time interval measured from the end of the diastolic mitral annular velocity pattern to the onset of QRS (the AQ interval) would be a useful parameter in predicting LVEDP. The aim of this study was to evaluate the relation between the AQ interval and LVEDP. Forty-six patients with suspected coronary artery disease who underwent Doppler echocardiographic studies and cardiac catheterization were included. LVEDP was determined using a micromanometer-tipped catheter. On univariate analysis, the AQ interval had positive correlations with the PR interval (r = 0.405, p = 0.005), transmitral E-wave velocity (r = 0.502, p <0.001), isovolumic contraction time (r = 0.635, p <0.001), and LVEDP (r = 0.514, p <0.001) and a negative correlation with E-wave deceleration time (r = -0.430, p = 0.003). After stepwise multiple linear regression analysis, the PR interval, transmitral E-wave velocity, and LVEDP were the independent predictors of the AQ interval (beta = 0.234, p = 0.033; beta = 0.331, p = 0.004; and beta = 0.350, p = 0.003, respectively). In conclusion, the AQ interval is a novel, simple, and easily obtained index in the prediction of LVEDP.

Cardiac Catheterization↗
PubMed2006

Septum hematoma: a complication of retrograde wiring in chronic total occlusion.

In spite of the remarkable technological innovation and improved outcomes with percutaneous coronary intervention (PCI), chronically total occlusion in coronary arteries (CTO) remains a formidable challenge for coronary interventionalist. Recently Japanese interventionists have proposed a retrograde wiring technique which provides another way to resolve such difficulties. The retrograde wire in the distal CTO vessel can then be used as a clear landmark in the distal true lumen, facilitating antegrade wiring and possibly increasing the success rate of CTO-PCI. Reported here is a patient who experienced retrograde wire technique but suffered from a complication with septum hematoma and myocardial infarction. The patient had a complete recovery of chest symptoms and resolution of septum hematoma in 1 month. Retrograde wire manipulation should be used as a last resort and via a large collateral vessel in the treatment of CTO.

Angioplasty, Balloon, Coronary↗
PubMed2006

Association between hypertension and primary mitral chordae tendinae rupture.

BACKGROUND: Mitral regurgitation from chordae tendinae rupture (CTR) may cause severe clinical symptoms and is a progressive disease that eventually results in the need for mitral valve surgery. Early recognition of CTR and identification of risk factors are important because early intervention increases the chances of survival. Hypertension may increase mitral valve complex mechanical strain and cause the chordae tendinae to rupture. METHOD: Using a cross-sectional study of medical files in one medical center in Taiwan, we enrolled 98 patients with mitral CTR and classified them into two groups, comprising 68 subjects (69%) without obvious predisposing factors (primary group) and 30 subjects (31%) with known predisposing causes (secondary group). RESULT: Of the subjects, 63 (64%) were men with a mean age of 57.5 +/- 1.5 years. The posterior mitral leaflet was most commonly involved (64%). The known predisposing factors in secondary group include mitral valve prolapse, infective endocarditis, and rheumatic heart disease. The patients who had primary CTR were older (59.9 +/- 1.6 v 52.1 +/- 3.1 years, P = .029), had a higher prevalence of hypertension (56% v 30%, P = .018) and complained more often of dyspnea (82% v 53%, P = .003) than the patients in the secondary group. Using binary logistic regression analyses, the variation in primary group was found to be independently explained by age (P = .039, odds ratio = 1.039, 95% confidence interval = 1.002 to 1.077) and hypertension (P = .048, odds ratio = 2.717, 95% confidence interval = 1.008 to 7.326). CONCLUSION: We conclude that hypertension was an independent predictor for primary CTR in this study.

Age Factors↗
PubMed2006

Single-beat differentiation among left ventricular filling patterns by pulsed wave Doppler echocardiography.

We sought to evaluate whether the combination of phantom E wave peak velocity (Ep) to phantom A wave peak velocity (Ap) ratio at the apex (Ep/Ap) and pulsed wave Doppler left ventricular (LV) inflow propagation velocity (LVIPVpw) or the combination of Ep/Ap and Ep/LVIPVpw obtained from the same heartbeat can effectively differentiate LV filling patterns. The study population included 132 patients. They were classified into normal, abnormal relaxation, and pseudonormal/restrictive groups according to the ratio of early to late transmittal filling wave peak velocity (E/A), color M-mode Doppler LV inflow propagation velocity, and E/color M-mode Doppler LV inflow propagation velocity. Standard Doppler parameters of LV filling such as E, A, E/A, and E-wave deceleration time had a bimodal distribution, but LVIPVpw decreased and Ep/LVIPVpw increased progressively with worsening of LV diastolic function (both P < .001). The sensitivity and specificity of combination of Ep/Ap 1 or greater and LVIPVpw less than 77 cm/s or of Ep/Ap 1 or greater and Ep/LVIPVpw greater than 0.87 from the same heartbeat in identifying the pseudonormal/restrictive LV filling pattern were 81% and 95% or 81% and 93%, respectively. In conclusion, with application of range ambiguity phenomenon, it is simple and feasible to differentiate LV filling patterns on the same cardiac cycle by pulsed wave Doppler echocardiography.

Adult↗
PubMed2006

Lercanidipine and losartan effects on blood pressure and fibrinolytic parameters.

Antihypertensive agents may modulate fibrinolysis in addition to reducing blood pressure. We conducted a randomized trial to assess the effects of lercanidipine and losartan on blood pressure (BP) lowering and three fibrinolytic parameters: plasminogen activator inhibitor-1 (PAI-1), D-dimer, and fibrinogen. All patients enrolled had essential hypertension and underwent a placebo run-in period of 2 weeks before randomization to either lercanidipine tablets 10-20 mg once daily or losartan tablets 50-100 mg once daily. Twenty-six patients completed this study. After 8 weeks of treatment, both groups of patients had significantly reduced systolic (SBP) and diastolic BP (DBP) (SBP, p = 0.034 and 0.050, respectively; DBP, p = 0.018 and 0.034 for lercanidipine and losartan, respectively). Both drugs were well tolerated. Only in the group treated with lercanidipine was PAI-1 concentration significantly reduced (57.1 +/- 4.7 to 43.1 +/- 4.8 ng/mL, p = 0.047). No difference was found with D-dimer and fibrinogen in either group. This study shows that both lercanidipine and losartan are effective antihypertensive drugs in patients with essential hypertension. Lercanidipine may provide additional benefit in fibrinolysis.

Antihypertensive Agents↗
PubMed2006

An avoidable complication of percutaneous coronary intervention-entrapment of stent and disconnected balloon catheter.

During percutaneous coronary intervention, entrapment of catheter materials is a rare but life-threatening complication that sometimes requires emergency surgical treatment. Coronary artery stents have been developed to prevent acute coronary closure and reduce restenosis after coronary angioplasty. The most frequently reported complications of coronary stents are related to stent thrombosis and anticoagulation problems. This case study describes a 60-year-old female who had stable angina pectoris and underwent stent insertion into the left circumflex artery. Unfortunately, the coronary stent with balloon catheter was entrapped while crossing the angulated segment between the left circumflex and left main coronary artery. The stent catheter was surgically removed, and the patient underwent coronary artery bypass grafting successfully. Physicians should keep in mind that extremely angulated segments may reduce the successful rate of coronary stenting and contribute to the stent entrapment complication.

Angioplasty, Balloon, Coronary↗
PubMed2006

Randomized comparative study of the effects of treatment with once-daily, niacin extended-release/lovastatin and with simvastatin on lipid profile and fibrinolytic parameters in Taiwan.

Hyperlipidemia can be effectively treated either with niacin or HMG-CoA reductase inhibitor (statin), or a combination of both. Few reports showed the effects of the combination regimen with niacin and statin on hemostatic functions. We conducted a single-center, double-blind, double-dummy, randomized, two-arm study to assess the effects of the niacin extended-release/lovastatin therapy in a fixed-dose formulation and of simvastatin on lipid lowering and two fibrinolytic parameters, fibrinogen and d-dimer. All patients were enrolled according to NCEP-ATP III guidelines and underwent a placebo run-in period of 4 weeks before being randomized to either niacin extended-release/lovastatin tablets (500/20 mg) once daily (n = 36) or simvastatin capsule (20 mg) once daily (n = 34). After 16 weeks of treatment, both groups of patients showed significantly reduced low-density lipoprotein cholesterol and total cholesterol (LDL-C, p < 0.001 and < 0.001, respectively, p = 0.159 between the groups; TC, p < 0.001 and < 0.001, respectively, p = 0.018 between the groups). Both drugs were well tolerated. Only in the group treated with niacin extended-release/lovastatin was fibrinogen concentration significantly reduced after treatment (2.48 +/- 0.65 to 1.99 +/- 0.62 g/L, p = 0.008). No difference was found with d-dimer in either group. This study shows that both niacin extended-release/lovastatin and simvastatin are effective and well-tolerated lipid-lowering drugs in Taiwanese patients with dyslipidemia. A combinational treatment with niacin extended-release/lovastatin may provide additional benefit in fibrinolysis.

Aged↗
PubMed2006

St-segment elevation acute myocardial infarction in a patient with acromegaly: a case report and literature review.

Acromegaly is a disorder caused by the excess production of pituitary growth hormone and is characterized by the enlargement of the hands, feet and head. Increased morbidity and mortality with acromegaly is associated with cardiovascular complications, hypertension, glucose intolerance, cardiomyopathy and coronary artery disease. We report a case of acromegaly, which presented with ST-segment elevation acute myocardial infarction. The patient received successful primary transluminal coronary angioplasty with stent implantation. Acromegaly was suspected from typical appearance, and confirmed with hormonal examination and imaging of the pituitary mass. We discuss this case in comparison with previous literature.

Acromegaly↗
PubMed2006

Gitelman syndrome: report of three cases and literature review.

Gitelman syndrome (GS) is a rare autosomal recessive, inherited renal tubular disorder. Herein, we report three cases of GS, one sporadic case and two siblings. They have typical laboratory findings, including hypokalemia, metabolic alkalosis, hypomagnesemia, and hypocalciuria. All of them were treated with oral potassium and magnesium supplements. They received regular pediatric clinic follow-up to check electrolytes and monitor development. These three cases reminded us that doctors should be alert to unexplained hypokalemia, which is usually the initial presentation of GS.

Adolescent↗
PubMed2006

Traumatic tricuspid insufficiency with chordae tendinae rupture: a case report and literature review.

With the increase in the number of automobile accidents, traumatic tricuspid insufficiency, a rare complication of non-penetrating blunt chest injury, has become an important problem. This kind of injury has been found more frequently during the last decade, partly because of better diagnostic procedures and a better understanding of the pathology. Here, we report a 22-year-old male patient who suffered chest trauma from an automobile accident. Echocardiography demonstrated tricuspid chordae tendinae rupture with remarkable tricuspid regurgitation. We discuss this case in comparison with the previous literature. This case reminds us that physicians in the emergency department should be aware of this potential complication following non-penetrating chest trauma.

Adult↗
PubMed2006

Differentiation of left ventricular diastolic dysfunction, identification of pseudonormal/restrictive mitral inflow pattern and determination of left ventricular filling pressure by Tei index obtained from tissue Doppler echocardiography.

BACKGROUND: Tei index obtained from tissue Doppler echocardiography (TDE-Tei index) has an inherent advantage of recording its systolic and diastolic components simultaneously on the same cardiac cycle. The aims of this study are to evaluate whether TDE-Tei index also exerts a correlation with left ventricular (LV) systolic and diastolic function and filling pressure and to see whether it can effectively identify the pseudonormal/restrictive mitral filling pattern. METHODS: Echocardiographic examination was performed in 243 consecutive patients. These patients were classified into three groups as normal, abnormal relaxation, and pseudonormal/restrictive groups according to the transmitral E/A-wave velocity (E/A), early diastolic velocity of lateral mitral annulus (Ea) and E/Ea. RESULTS: Standard Doppler indices of LV filling such as E, A, E/A, and E-wave deceleration time had a bimodal distribution, but Ea decreased and E/Ea and TDE-Tei index increased progressively with worsening of LV diastolic function. The sensitivity and specificity of TDE-Tei index>0.51 in the discrimination of pseudonormal/restrictive filling pattern were 85% and 96%, respectively. After stepwise multiple linear regression analysis, TDE-Tei index had a significant negative correlation with Ea (beta=-0.296, P<0.001) and ejection fraction (beta=-0.293, P<0.001) and positive correlation with E/Ea (beta=0.235, P=0.001). CONCLUSIONS: TDE-Tei index increased with worsening of LV diastolic function and can effectively identify the pseudonormal/restrictive mitral inflow pattern. It also correlated with the echocardiographic parameters of LV systolic and diastolic function and filling pressure. It suggests that TDE-Tei index is a simple and feasible marker in assessing global LV function.

Adult↗
PubMed2006

Preload independence of isovolumic relaxation flow propagation velocity.

To evaluate whether isovolumic relaxation flow propagation velocity (IRFPV) is independent of preload alterations, 41 healthy subjects (35 +/- 7 years) were included for Doppler examinations at three different positions, i.e., supine, Trendelenburg, and reverse Trendelenburg. A positional difference was detected in the peak velocity of the transmitral early diastolic flow wave (P = 0.012) and the peak velocities of both early (P = 0.004) and late (P = 0.007) diastolic mitral annular velocity waves. In contrast, there was no positional difference in the early diastolic inflow propagation velocity or IRFPV. In conclusion, IRFPV is a preload-independent Doppler parameter.

Adult↗
PubMed2005

Polarization controllable spatial filter based on azo-dye-doped liquid-crystal film.

This investigation establishes the feasibility of exploiting the surface-assisted photoalignment effect in dye-doped liquid-crystal (DDLC) films as spatial filters with controllable polarization in optical signal processing. The fabrication relies on the fact that the various intensities of the diffracted orders are responsible for various changes of the polarization state induced by the photoaligned DDLC film. Specific spatial orders in Fourier optical signal processing can be filtered by use of an analyzer placed behind the sample to control the polarization state of the diffracted orders. A simulation was performed, and the results agree closely with the experimental data.

Journal Article↗
PubMed2005

Photophysical and electrochemical properties of 1,7-diaryl-substituted perylene diimides.

Substituent effects on the photophysical and electrochemical properties of 1,7-diaryl-substituted perylene diimides (1,7-Ar(2)PDIs) have been carefully explored. Progressive red-shifts of the absorption and emission maxima were observed when the electron-donating ability of these substituents was increased. Linear Hammett correlations of 1/lambda(max) versus sigma(+) were observed in both spectral analyses. The positive slopes of the Hammett plots suggested that the electronic transitions carry certain amounts of photoinduced intramolecular charge-transfer (PICT) character from the aryl substituents to the perylene diimide core which leads to the reduction of the electron density on the substituents. The substituent electronic effects originated mainly from the perturbation of the core PDI HOMO energy level by the substituents. This conclusion was supported by PM3 analyses and confirmed by cyclic voltammetry experiments. More interestingly, the Ph(2)NC(6)H(4)-substituted PDI, 4i, showed an unusual dual-band absorption that spans from 450 to 750 nm. We tentatively assigned these two bands as the charge-transfer band and the PDI core absorption, respectively.

Journal Article↗