Biomedical subjects

Hsueh-Wei Yen

Publications and source records attributed to Hsueh-Wei Yen.

At least 19 recordsLinked to original sources

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

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

Effects of different contrast media on glutathione peroxidase and superoxide dismutase activities in the heart and kidneys of normal and streptozotocin-induced diabetic rats.

BACKGROUND/PURPOSE: Hemodynamic changes and contrast nephropathy are well known complications of contrast media injection. However, the mechanisms of toxicity leading to these complications remain unclear. We hypothesized that contrast media toxicity would manifest as a change in antioxidant enzyme activity, thus leading to tissue damage. METHODS: This study investigated the effects of injection of ionic high-osmolar diatrizoate, ionic low-osmolar ioxaglate, and nonionic low-osmolar iopromide on the activities of two antioxidant enzymes, glutathione peroxidase (GPX) and superoxide dismutase (SOD), in the heart and kidney tissue of normal male Wistar rats (n = 51) and streptozotocin (STZ)-induced diabetic rats (n = 54). Activities of GPX and SOD were assayed spectrophotometrically. RESULTS: Renal GPX activities were significantly decreased in both normal (458.3 +/- 64.6 to 385.5 +/- 63.4 mU/mg, p = 0.005) and diabetic rats (669.0 +/- 98.1 vs. 564.0 +/- 153.3 mU/mg, p = 0.035) at 1 hour after diatrizoate injection. Renal SOD activities were not affected after contrast injection. Ioxaglate and iopromide injection did not cause any change in renal antioxidant enzyme activity. In contrast to kidney tissue, there was no significant change in GPX and SOD activities in heart tissue at 1 hour after injection of different contrast media. CONCLUSION: Intravenous injection of ionic high-osmolar diatrizoate reduced renal GPX activity during the first hour in both normal and STZ-induced diabetic rats. Heart tissue was not prone to antioxidant enzyme activity changes after intravenous contrast media injection. GPX activity reduction can be an important mechanism of nephrotoxicity after contrast media injection.

Animals↗

PubMed2006

Positive interference from contrast media in cardiac troponin I immunoassays.

Cardiac troponin I (cTnI) has been found to be a sensitive and reliable marker of myocardial damage, and elevated levels of cTnI can indicate high risk for acute coronary syndrome. To determine how to intervene in possible cases of acute coronary syndrome, cTnI levels must be measured by immunoassay. However, cTnI immunoassay results are prone to interference from many substances such as heparin and common drugs. The contrast media used in the coronary angiography might also interfere with results. To explore this possibility, we performed two in vivo and two in vitro studies. In the first in vivo study, we evaluated the effects of contrast media on cTnI immunoassays by collecting blood samples from 45 patients undergoing coronary angiography before and after the procedure. We used the Opus Magnum immunoassay system to measure cTnI levels. In the second in vivo study, we collected 25 blood samples from another group of patients also undergoing angiography at various times before and after the procedure to determine cTnI values by both the Opus Magnum and ACCESS systems. In the first in vitro study, 12 different contrast media were treated as samples to disclose the potential interference of measurement in the two assay systems. In the second in vitro study, we made sequential dilutions of iopromide (Ultravist; Schering) with serum to explore their potential for interfering with the detection of cTnI by the Opus Magnum and ACCESS assays. In the first in vivo study using the Opus Magnum assay, cTnI concentrations in samples taken after angiography were significantly higher at 5 minutes than at 30 minutes, and, at 60 minutes, all cTnI concentrations had dropped below the cutoff point. In the second in vivo study, we found a substantial difference in detection of cTnI by the Opus Magnum and ACCESS assays. All cTnI concentrations checked by ACCESS assay were below the cutoff value. In our first in vitro study, the Opus Magnum assay gave false positive results for all 12 contrast media; the ACCESS assay gave a positive result for only one contrast medium, poppy-seed oil (Lipiodol; Guebert). In our second in vitro study, we found that, in the Opus Magnum assay, the more concentrated the contrast medium, the higher the cTnI value, but not in the ACCESS assay. We conclude that contrast media may cause false-positive results in cTnI assays and that, when contrast media are being used for angiography, cTnI results, especially those based on samples taken within the first hour of the procedure, should be interpreted carefully.

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

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

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

Influence of withdrawal of statin treatment on proinflammatory response and fibrinolytic activity in humans: an effect independent on cholesterol elevation.

BACKGROUND: In addition to lowering lipid profile, statins have pleiotropic effects on improving vascular function. Changes of these pleiotropic effects and their relationship to lipid profile after withdrawal of statin treatment remained unclear. METHODS: We investigated the changes of lipid profile and plasma concentrations of human soluble vascular cell adhesion molecule-1 (sVCAM-1) and human tissue type plasminogen activator (tPA) after withdrawal of statin treatment. Twenty-two patients (14 F, 8 M, aged 63+/-13 years) with hypercholesterolemia were treated with atorvastatin (ATOR; 10 mg/day) for 12 weeks. Blood samplings for serum lipid and markers were collected before, after and withdrawal of statin treatment. RESULTS: The total cholesterol, LDL-cholesterol and sVCAM-1 (from 394.4+/-251.7 to 321.0+/-198.9 ng/ml, p<0.05) all decreased significantly and the tPA (from 9.47+/-3.57 to 11.62+/-3.99 ng/ml, p<0.05) increased significantly after atorvastatin treatment. During the following 3 days after withdrawal of atorvastatin, the total cholesterol and LDL-cholesterol did not show any significant change. However, the plasma sVCAM-1 significantly elevated on day 2 (from 321.0+/-198.9 to 371.2+/-220.4 ng/ml, p<0.05) and the plasma tPA significantly decreased on day 1 (from 11.62+/-3.99 to 10.52+/-3.55 ng/ml, p<0.05) and day 3 (from 11.62+/-3.99 to 10.27+/-3.69 ng/ml, p<0.05). Both the significant elevation of sVCAM-1 and decrease of tPA after withdrawal of atorvastatin treatment occurred within 3 days, while the serum cholesterol and LDL-chol levels did not have any significant change and were still within the therapeutic range. CONCLUSIONS: After 12 weeks of atorvastatin treatment, the beneficial pleiotropic effects can be demonstrated simultaneously with lowering the lipid profile. However, after withdrawal of atorvastatin, the beneficial pleiotropic effects are abrogated rapidly within days and are independent on elevation of serum cholesterol.

Aged↗

PubMed2005

Left ventricular inflow propagation velocity at pulsed wave Doppler analysis: an index of relaxation.

To test whether left ventricular inflow propagation velocity at the pulsed wave Doppler analysis (IPVpw) is a useful noninvasive index of relaxation, 21 patients under coronary angiography for chest pain were included for simultaneous catheter-based and Doppler studies. IPVpw was derived through the application of range ambiguity, and the time constant of isovolumic left ventricular pressure decline (tau) was acquired by a previously described method. At baseline status, IPVpw correlated significantly with the peak negative dP/dt and tau ( r = -0.609, P = .003), but not with the peak velocity of transmitral early flow (E) wave. Sublingual application of nitroglycerin increased heart rate, decreased the transmitral E velocity and transmitral E-to-A velocity ratio, and prolonged the deceleration time of the transmitral E wave. However, there was no significant impact on IPVpw, peak negative dP/dt, or tau. IPVpw correlated with tau ( r = -0.533, P < .001) at the combined analysis of the data before and after nitroglycerin application. In conclusion, IPVpw is a preload-independent, noninvasive index of left ventricular relaxation.

Blood Flow Velocity↗

PubMed2005

Isovolumic relaxation flow propagation velocity in patients with diseases impairing ventricular relaxation.

To evaluate the propagation velocity of isovolumic relaxation flow within the left ventricle (IRFPV) associated with impaired ventricular relaxation, 49 patients with diseases known to impair ventricular relaxation (disease group) and 38 age-matched control subjects (control group) were studied. IRFPV was measured as the slope of the first aliasing velocity line segment of the isovolumic relaxation flow wave front in the color M-mode Doppler echocardiogram. Compared with the control group, the disease group had thicker interventricular septum and left ventricular posterior wall, more left ventricular mass, and lower early diastolic mitral annular velocity (8 +/- 3 vs 11 +/- 4 cm/s, P < .001), early (E) wave propagation velocity (47 +/- 16 vs 70 +/- 41 cm/s, P = .002), and IRFPV (193 +/- 149 vs 395 +/- 220 cm/s, P < .001). No matter in subgroup or whole population analysis, either the early diastolic mitral annular velocity or the E wave propagation velocity was selected as one of the determinants of IRFPV. In conclusion, diseases impairing ventricular relaxation may retard IRFPV.

Aortic Valve Stenosis↗

PubMed2005

Effects of total coronary artery occlusion on vascular endothieial growth factor and transforming growth factor beta.

Vascular endothelial growth factor (VEGF) and transforming growth factor beta (TGF-beta1) play an important role in angiogenesis. We wanted to determine if concentrations of growth factors in the coronary sinus (CS) and right atrium (RA) are higher in coronary artery disease patients with total occlusions than in those with partial occlusions. Fifty-one patients scheduled for coronary artery angiography were evaluated for possible recruitment. A 6F Goodale-Lubin catheter was used to collect blood from the CS and RA. Data for all but four patients were gathered successfully, leaving 47 study patients. The reviewer was blinded to growth factor data when interpreting coronary angiographic findings. Of the 47 enrolled patients, 32 had at least one diseased vessel, seven of whom had at least one major total epicardial coronary occlusion. In all 32 patients, the concentrations of VEGF in the CS were higher than those in the RA (31.5 +/- 2.7 vs 27.1 +/- 1.8 pg/mL; p = 0.005). Patients with total occlusions had higher VEGF concentrations in the CS than those with non-total occlusions (38.9 +/- 8.0 vs 29.5 +/- 2.6 pg/mL; p = 0.037). The differences in TGF-beta1 in the two groups were not statistically significant. The higher CS VEGF concentrations in patients with total occlusion indicate that VEGF may play a part in the development of angiogenesis.

Aged↗

PubMed2005

Vascular endothelial growth factor in coronary sinus: evidence for its association with coronary collaterals.

OBJECTIVES: To explore whether local growth factors concentration, including vascular endothelial growth factor (VEGF) and transforming growth factor beta one (TGF-beta(1)), influence the formation of coronary collaterals. DESIGN: Thirty-six patients scheduled for coronary angiography received a 6F Goodale-Lubin catheterization to collect blood from the coronary sinus (CS) and right atrium (RA). RESULTS: Patients with coronary collaterals had a higher number of diseased vessels (2.6+/-0.2 vs. 1.4+/-0.3, p = 0.005), higher percentage of severity of stenosis (93+/-2 vs. 48+/-8, P < 0.001) and higher VEGF concentrations in CS (38.9+/-3.9 pg/ml vs. 20.8+/-1.4 pg/ml, P < 0.001) and in RA (31.7+/-3.1 pg/ml vs. 22.0+/-2.3 pg/ml, p = 0.004). There was no significant relationship between coronary collateral formation and TGF-beta(1) concentration. By binary logistic regression analysis, VEGF concentrations in CS (p = 0.030) and stenosis severity (p = 0.042) are correlated positively with collateral formation. CONCLUSIONS: The association between local, endogenous secretion of VEGF and coronary collateral formation is compatible with a paracrine role for this growth factor in pathophysiologic collateral formation.

Collateral Circulation↗

PubMed2005

Left ventricular Tei index: comparison between flow and tissue Doppler analyses.

BACKGROUND: It is still unknown whether a correlation exists between left ventricular Tei index obtained by tissue Doppler imaging and that determined by flow Doppler waveforms. This study was conducted to evaluate their relationship and to assess the positional effect on them. METHODS: Twenty-six healthy subjects and 25 patients with essential hypertension were included. On the tissue Doppler images, the time interval from the end to the onset of the mitral annular velocity pattern during diastole and the duration of the S-wave were used to calculate tissue Doppler Tei index. RESULTS: The tissue Doppler Tei index correlated with the flow Doppler Tei index at sitting position (r = 0.406, P = 0.003), but not at left lateral decubitus position. The limits of agreement for the Tei index measured by both methods were -0.26 to 0.62 at left lateral decubitus position and -0.09 to 0.55 at sitting position. Preload reduction associated with sitting position with dangling feet raised the Tei index both in the healthy controls [0.54 (0.14) vs 0.42 (0.12), P < 0.001] and in the hypertensives [0.53 (0.15) vs 0.46 (0.12), P = 0.005]. There was a similar positional effect on the tissue Doppler Tei index in the control subjects [0.75 (0.12) vs 0.53 (0.10), P < 0.001]. CONCLUSIONS: Tissue Doppler Tei index does not seem to be a suitable substitute for flow Doppler Tei index. Flow Doppler Tei index is preload dependent and the loading status should be taken into consideration at the application of Tei index to the evaluation of myocardial performance.

Adult↗

PubMed2004

Effect of withdrawal of statin on C-reactive protein.

BACKGROUND: C-reactive protein is considered a risk factor for coronary artery disease. In addition to its lipid-lowering properties, statin decreases the level of C-reactive protein. Abrupt cessation of statin therapy during treatment could increase the incidence of cardiac events in patients with atherosclerotic heart disease. The changes of C-reactive protein after withdrawal of statin therapy are still unknown. METHODS: Twenty patients with hyperlipidemia received statin (atorvastatin, 10 mg/day) therapy for 3 months. The levels of lipid profiles and C-reactive protein were assessed before receiving the statin therapy, immediately after 3 months of therapy, and on the 3 consecutive days after withdrawal of statin treatment. RESULTS: After 3 months of statin therapy, the total cholesterol, low-density lipoprotein cholesterol (LDL-chol), and C-reactive protein were significantly reduced (264.94 +/- 16.23 vs. 183.44 +/- 16.34 mg/dl, 183.17 +/- 34.56 vs. 122.00 +/- 17.66 mg/dl, and 2,309.00 +/- 437.85 vs. 1,257.95 +/- 207.99 ng/ml, respectively). The level of C-reactive protein increased on the second day after withdrawal of statin therapy (2,590.14 +/- 1,045.05 vs. 1,257.95 +/- 207.99 ng/ml); however, the total cholesterol and LDL-chol did not increase during the 3-day period after withdrawal of statin therapy. CONCLUSIONS: The increase in the level of C-reactive protein after withdrawal of statin therapy may be a contributing factor to the increased incidence of cardiac events in patients who have abruptly stopped statin therapy.

Aged↗

PubMed2004

Propagation velocity of mitral late flow toward the apex in healthy participants.

The transit time of mitral late flow (A wave) to the outflow tract (A-Ar interval) has been demonstrated to be shorter in the presence of increased ventricular stiffness. However, the A-Ar interval is just a measure of time duration and the data of intraventricular A-wave propagation velocity are still unavailable. In this study we presented the aging trend in various intracardiac Doppler signals, including the mitral A-wave propagation velocity toward the apex (APV(apex)). It was measured as the slope of the first aliasing velocity line segment of the mitral A wavefront at color M-mode Doppler analysis. Age correlated significantly with peak velocity of mitral early flow (E wave), peak A velocity, velocity ratio of E to A wave, deceleration time of E wave, and mitral E-wave propagation velocity toward the apex, but not with the A-Ar interval (r = -0.262, P =.066) or the APV(apex) (r = -0.047, P =.748). Neither the A-Ar interval nor the APV(apex) was different between the young and the elderly groups. Furthermore, there was no significant correlation between the APV(apex) and the A-Ar interval (r = -0.135, P =.348). In conclusion, aging has a major adverse impact on myocardial relaxation associated with a minor one on the noninvasive indices of ventricular compliance. The APV(apex) is age-independent and, moreover, there is no significant correlation between the APV(apex) and the A-Ar interval.

Adult↗

PubMed2004

Effect of electrophysiologic character of ventricular premature beat on heart rate turbulence.

Heart rate turbulence (HRT) has been described as a predictor of high-risk patients with cardiac diseases. The purpose of this study is to determine how the degree of prematurity of a ventricular premature beat (VPB%) and retrograde ventriculoatrial (VA) conduction of VPBs affect HRT. We studied 30 patients without organic heart disease. We calculated turbulent slope (TS) and turbulent onset (TO) from VPBs induced by programmed stimulation from the right ventricular apex. TS was inversely and TO was positively correlated to VPB%. Without retrograde VA conduction of VPBs, TS was inversely and TO was positively correlated to VPB%. In VPBs with retrograde VA conduction, there were no significant correlations between TO and TS with VPB%. In conclusion, TS and TO calculated from VPBs with different degrees of prematurity varied widely. Both VPB% and characteristics of retrograde VA conduction may affect HRT.

Adult↗