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Biomedical subjects

Lexin Wang

Publications and source records attributed to Lexin Wang.

At least 37 records · Page 2Linked to original sources
PubMed2004

Clinical features and management of congenital long QT syndrome: a report on 54 patients from a national registry.

To assess the clinical features and the management of congenital long QT syndrome (LQTS) in China, we collected the clinical data of 54 LQTS patients (14 males and 40 females) from our newly established national registry. All patients were symptomatic, with syncope being the most common symptom. The average age when the first symptoms occurred was 17.9 +/- 15.6 (range, 0.5-62) years; 55.6% of them had the first symptoms before the age of 20. The most common triggers of the symptoms were physical exercise or emotional stress. The average corrected QT interval was 0.55 +/- 0.08 s. Using ECG criteria, there were 14 (25.9%) LQT1 patients, 28 (51.9%) LQT2, and 2 (3.7%) LQT3. Thirty (55.6%) patients were treated with Beta-blockers at the time of enrollment, with propranolol being the most commonly used drug, with an average daily dose of 57.5 +/- 39.1 mg. Four patients underwent left cardiac sympathectomy. After an average follow-up of 24.9 +/- 13.2 months, 3.1% (1/32) of patients with antiadrenergic therapy and 9.1% (2/22) without antiadrengergic therapy died of sudden cardiac death ( P < 0.05). We concluded that LQT2 might be the most common subtype in these patients. Antiadrenergic treatment was underused, raising the urgent need for educating both physicians and patients on the nature of the disease and its optimal antiadrenergic therapy.

Adrenergic beta-Antagonists↗
PubMed2004

Nitric oxide and prostacyclin mediate coronary shear force-induced alterations in cardiac electrophysiology.

Previous studies have shown that an increase in coronary flow or shear force enhances the oxygen consumption and contractility of myocardium (the "Gregg effect"). Recent studies have indicated that an increase in coronary shear force also affects atrioventricular conduction and ventricular repolarization. The mechanisms of "Gregg effect" and the shear force-induced alterations in cardiac electrophysiology are unclear. It has been proposed that the distension of the coronary arteries and the stretch of the surrounding myocytes may play a key role but this is not supported by the latest studies. Intracoronary perfusion increases coronary endothelial synthesis of nitric oxide and prostacyclin. Emerging evidence has indicated that both nitric oxide and prostacyclin prolong the action potential duration or effective refractory period in the in vitro and in vivo animal heart. We therefore hypothesized that shear force-induced alterations in cardiac function and electrophysiology are largely attributed to the enhanced endothelial release of nitric oxide and prostacyclin.

Adaptation, Physiological↗
PubMed2004

Left cardiac sympathetic denervation as the first-line therapy for congenital long QT syndrome.

Congenital long QT syndrome (LQTS) is a cardiac electrophysiological disorder due to genetic mutations. Patients with LQTS, if untreated, have a high incidence of ventricular tachycardia and cardiac arrest. Adrenergic activities are believed to play a major role in triggering the onset of cardiac events. The current mainstay of therapy for LQTS is oral beta-blockers, which improves clinical symptoms and reduces the incidence of sudden cardiac death in approximately 70% of the patients. Left cardiac sympathetic denervation (LCSD) is an alternative therapy for patients who are resistant to beta-blockers. Its clinical use, however, has been hindered by the complexity of the procedure and complications after the surgery. Video-assisted thoracoscopic sympathectomy has been used to treat patients with palmar and axillary hyperhidrosis. We suggest that the use of the microinvasice thoracoscopic technique may greatly simplify the LSCD procedure, making it the first-line therapy for LQTS.

Cardiac Surgical Procedures↗
PubMed2004

Can local ventricular fibrillation interval predict ventricular refractory period in human hearts?

Assessment of the spatial dispersion of ventricular refractory periods has become an important part of electrophysiological study in both experimental and clinical settings, because inhomogeneity of ventricular refractoriness is associated with an increased risk of life-threatening ventricular arrhythmias. Previous animal studies in dog and sheep have demonstrated that local ventricular fibrillation (VF) intervals measured from the heart surface correlate well with the ventricular effective refractory periods measured from the same ventricular sites. We hypothesise that local VF intervals may also predict the ventricular refractory periods in human hearts, hence, can be used to assess the spatial dispersion of refractoriness and to predict the risk of ventricular arrhythmias.

Animals↗
PubMed2004

Rheumatoid arthritis increases the risk of coronary heart disease via vascular endothelial injuries.

Patients with rheumatoid arthritis (RA) have an increased prevalence of coronary heart disease and a high cardiovascular mortality rate. The causes of increased coronary heart disease in RA patients are poorly understood. Conventional cardiovascular risk factors, such as inactivity, overweight or dyslipidemia may play a role, but they do not seem to be wholly responsible for the increased cardiovascular risk. RA is associated with a high incidence of inflammation and vascular endothelial injuries. Endothelial dysfunction is one of the key steps in the pathogenesis of atherosclerosis in non-RA patients. Therefore, we hypothesized that inflammation-induced vascular endothelial injuries may be responsible for the increased risk of coronary heart disease and high rates of cardiovascular mortality in patients with RA.

Arthritis, Rheumatoid↗
PubMed2004

Prevalence of overweight and smoking patients with coronary heart disease in rural China.

OBJECTIVE: To investigate the prevalence of overweight and/or smoking patients with coronary artery disease in rural China. DESIGN: A prospective survey with qualitative, open-ended questionnaires. SETTING: Tertiary referral centre. SUBJECTS: 158 hospitalised patients (71 men and 87 women) with established coronary heart disease. MAIN OUTCOME MEASURES: To determine the prevalence of overweight and/or smoking hospitalised patients who had a definitive diagnosis of coronary artery disease and to determine participants understanding of these risk factors. RESULTS: Being overweight and smoking cigarettes were found in 32.7% and 15.2% of the participants, respectively. More than 70% of the overweight participants had neither knowledge nor counselling on their weight before the study. Most smokers believed smoking was harmful to their health and cardiac condition, and had tried unsuccessfully to quit smoking. CONCLUSIONS: There was a high prevalence of overweight and/or smoking patients with coronary heart disease. A systematic approach is urgently required to educate patients and primary care physicians, and to improve the management of being overweight and smoking cigarettes.

Adult↗
PubMed2004

Simplified approach to radiofrequency catheter ablation of paroxysmal supraventricular tachycardia.

AIM: To investigate the safety and efficacy of a simplified approach in radiofrequency catheter ablation of paroxysmal supraventricular tachycardia. METHODS: The study involved 239 patients (118 men and 121 women) with paroxysmal supraventricular tachycardia and normal 12-lead electrocardiographic (ECG) findings at sinus rhythm, who visited the Cardiology Department of Weifang Medical College Hospital between January 2000 and September 2003. The mean age of patients was 39.2+/-11.9 years. The patients were divided into two groups: one undergoing a conventional 5-catheter ablation (controls), and the other a simplified 3-catheter ablation (study group). The follow up after ablation lasted 12 months. No antiarrhythmic agents were prescribed to the patients with successful ablation. RESULTS: The conventional and the 3-catheter ablation group did not differ in ablation success (97.5% vs 98.3%, p=0.42) and recurrence of paroxysmal supraventricular tachycardia (2.5% vs 3.3%, p=0.23). The simplified approach was associated with a significantly shorter procedure duration (89.1+/-28.2 vs 96.1+/-21.2 minutes, p<0.01) and fluoroscopy time (10.7+/-2.6 vs 12.7+/-4.2 minutes, p<0.01). There were no significant differences between the two groups in the type and incidence of procedural complications and ablation success. CONCLUSIONS: The simplified 3-catheter ablation approach proved to be a safe and effective method for ablation of paroxysmal supraventricular tachycardia. However, further studies including larger sample of such patients are needed to assess the clinical outcomes and cost-effectiveness of this simplified procedure.

Adult↗
PubMed2003

Carbachol prolongs ventricular repolarisation through nitric oxide release in an intact heart.

AIMS: The primary ain of this study was to investigate the effect of carbachol on ventricular repolarisation in an intact animal heart. METHODS: In five sheep, carbachol was administered to the left circumflex coronary artery (LCX) at 1.0 and 2.5 micromol/ml/min respectively for 3 min. Multiple unipolar ECGs were acquired from the epicardium of LCX territory. Administration of carbachol at 2.5 micromol/ml/min was also repeated after pre-treatment with nitro-L-arginine (20 mg/kg), a nitric oxide synthase inhibitor. RESULTS: Carbachol at 1.0 or 2.5 micromol/ml/min resulted in a T wave inversion and ARI prolongation in the LCX territory. The increase in ARI at 1.0 and 2.5 micromol/ml/min was 38 +/- 17 and 58 +/- 14 ms respectively (p<0.05). T wave inversion and ARI prolongation at 2.5 micromol/ml/min was diminished by pre-treatment with nitro-L-arginine. CONCLUSIONS: Carbachol results in a dose-dependent prolongation in ventricular repolarisation in this open-chest animal model. This effect is partially mediated by endogenous nitric oxide.

Animals↗
PubMed2003

Video-assisted thoracoscopic sympathectomy for congenital long QT syndromes.

The feasibility, safety, and effectiveness of video-assisted thoracoscopic sympathectomy (VATS) for congenital long QT syndrome were assessed in four patients who had frequent syncopal events before the surgeries. Under general anaesthesia, the pleural cavity was entered via two small incisions in the left third and fifth intercostal spaces at the mid-axillary line. The left thoracic sympathetic chain was identified and resected from T2-T5. The lower one third of the left stellate ganglion was also resected. VATS resulted in a significant shortening in corrected QT intervals (QTc) in three patients, the average QTc of the four patients immediately before and after VATS was 538 +/- 76 and 512 +/- 57 ms, respectively (P = 0.047). The heart rate remained unchanged after the VATS (67 +/- 4 vs 69 +/- 4 beats/min, P > 0.05). There were no major perioperative complications apart from mild ptosis of the left upper eyelid in one patient who recovered in the following days. There was no recurrence in syncopal events after a 3-month follow-up. VATS is a safe and effective technique for left cardiac sympathectomy in patients with congenital long QT syndromes.

Adult↗
PubMed2003

Role of educational intervention in the management of comorbid depression and hypertension.

To assess the effect of health education on blood pressure control and depression symptoms, we conducted a prospective study in 272 patients with essential hypertension. Depression symptoms were assessed by the Zung Self-rating Depression Scale (SDS). There was no significant difference in the level of hypertension and SDS scores between the educational (n = 138) and control (n = 134) group before the study (p > 0.05). After 12 months of follow-up, the body mass index (BMI) was reduced in the educational group (23.6 +/- 2.6 vs 21.4 +/- 2.2 kg/m2, p < 0.01), but it remained unchanged in the control group. The average systolic and diastolic blood pressure were reduced in both groups, but the amplitude of systolic blood pressure reduction in the educational group was greater than that of the control group (7.9 +/- 2.3 vs 4.2 +/- 2.0 mmHg, p < 0.01). The incidence of depression (10.9% vs 10.4%) and the average SDS scores (32.4 +/- 6.7 vs 33.2 +/- 6.9) were similar between the two groups (p > 0.05). However, in the depressed patients who received hypertension education, the average systolic (160.2 +/- 12.4 mmHg) and diastolic (89.8 +/- 7.3 mmHg) blood pressure was significantly lower than that of the control group (169.1 +/- 16.8 and 96.8 +/- 13.0 mmHg, respectively, p < 0.01). We conclude that hypertension education does not reduce the incidence or symptoms of depression, but it may facilitate blood pressure management in patients with clinical depression.

Aged↗
PubMed2003

Congenital long QT syndrome: 50 years of electrophysiological research from cell to bedside.

Congenital long QT syndrome (LQTS) is a group of ion channel disorders of ventricular myocytes due to genetic mutations. The main symptoms of LQTS are pre-syncopal or syncopal attacks and cardiac arrest. Anti-adrenergic therapy with beta-blockers has been the mainstay of treatment. Left cardiac sympathectomy has also been used as an alternative in those in whom beta-blockers failed. ICDs are highly effective in preventing mortality and should be the first choice of therapy for those with cardiac arrest as the first symptom or those with LQT3 genotype not responding to anti-adrenergic therapy alone. Research on new therapeutic options, specifically those targeting at defective genes or mutant ion channels, may provide more effective treatment for this rare but potentially fatal electrophysiological disorder.

Adrenergic beta-Antagonists↗
PubMed2003

Electrocardiographic diagnosis of left atrial enlargement in patients with mitral stenosis: the value of the P-wave area.

OBJECTIVE: To investigate the value of the P-wave area in diagnosing left atrial enlargement in patients with mitral stenosis. METHODS: We measured the P-wave area from lead II of a standard 12-lead ECG in 136 consecutive patients with mitral stenosis. We also measured the left atrial diameter with two-dimensional echocardiography. RESULTS: Left atrial enlargement was identified in 120 (88.2%) patients. There was an excellent correlation between P-wave area and left atrial diameter in these patients (r = 0.739, p = 0.001). A P-wave area of > or = 4 ms x mv had an 85.8% sensitivity and 93.7% specificity for left atrial enlargement. There was also a smaller but significant correlation between left atrial diameter and the total P-wave duration (r = 0.635, p < 0.01) or P-wave amplitude (r = 0.683, p < 0.01) in these patients. However, the P-wave area had a better overall sensitivity than the P-wave duration (43.3%) or amplitude (10.8%) in diagnosing left atrial enlargement. CONCLUSIONS: Left atrium enlargement can be estimated by P-wave area measured from ECG lead II in patients with mitral stenosis. A P-wave area 24 ms x mv serves as a new criterion of left atrial enlargement.

Adolescent↗
PubMed2003

Influence of commissural calcification on the immediate outcomes of percutaneous balloon mitral valvuloplasty.

OBJECTIVES: To evaluate the impact of mild to moderate commissural calcification on the immediate outcomes of percutaneous balloon mitral valvuloplasty (PBMV). METHODS AND RESULTS: We analysed the results of 223 consecutive patients (mean age 37.6 +/- 8.7 years) who underwent PBMV for rheumatic mitral stenosis. Commissural calcification was identified with a two-dimensional echocardiography (echo) in 65 (29.1%) patients with the severity of calcification being graded from 0-3. The anatomy and function of the mitral valve were assessed byWilkins echo score. In patients with no commissural calcification the increase in mitral valve area after PBMV was 0.90 +/- 0.42 cm2, which was greater than the increase in those with calcification grade 1 (0.83 +/- 0.42 cm2, p < 0.05), grade 2 (0.72 +/- 0.38 cm2, p < 0.05) and grade 3 (0.63 +/- 0.13 cm2, p < 0.05). In patients with an echo score of < or = 8, the presence of commissural calcification was associated with a smaller increase in mitral valve area (p < 0.05) and a smaller reduction in New York Heart Association (NYHA) function class after PBMV (p < 0.05). In patients with an echo score of more than 8, commissural calcification had no significant effect on the valve area increase and NYHA function class reduction (p > 0.05). CONCLUSIONS: Commissural calcification has an adverse effect on the clinical results of PBMV. Detailed pre-procedural assessment of commissural calcification with echocardiography must be performed to provide background information on the immediate outcomes of PBMV.

Adolescent↗
PubMed2003

Management of cardiovascular risk factors in type 2 diabetic patients undergoing coronary angiography.

AIM: To investigate risk factor management in diabetic patients undergoing coronary angiography. METHODS: Hemoglobin (Hgb) A1c, low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), triglycerides (TG), blood pressure (BP), and body mass index (BMI) were cardiovascular risk factors analyzed in 284 consecutive type 2 diabetic patients who underwent coronary angiography. RESULTS: Coronary artery disease (CAD) was identified in 233 (82.0%) diabetic patients. The mean HgbA1c fraction for all patients at hospital admission was 9.7+/-1.4%. The mean concentration of LDL-C, HDL-C, and triglycerides was 2.82+/-0.9, 0.92+/-0.28, and 2.56+/-0.81 mmol/L, respectively. One hundred and twenty-two (43.0%) patients had LDL-C <2.6 mmol/L, 70 (24.7%) patients had a blood pressure of less than 130/85 mm Hg, and 158 (55.7%) had BMI <30 kg/m(2). Only 26 (9.1%) patients had optimal control of the above cardiac risk factors. The average LDL-C, triglycerides, and blood pressure in patients with severe coronary artery disease were higher than those in patients with moderate to mild coronary artery disease (p<0.01; unpaired t-test). CONCLUSIONS: Cardiovascular risk factors were poorly controlled in type 2 diabetic patients. The average LDL-C, triglycerides, and blood pressure in patients with severe coronary artery disease were higher than those in patients with moderate to mild coronary artery disease.

Aged↗
PubMed2003

Using left atrial esophagus impression after a barium swallow to determine the optimal septal puncture site during percutaneous balloon mitral valvuloplasty.

BACKGROUND: Transseptal catheterization is the key to a successful percutaneous balloon mitral valvuloplasty (PBMV). The primary aim of the study was to investigate new methods of transseptal catheterization for PBMV. METHODS: Eighty-four patients with rheumatic mitral stenosis were randomized into two groups for PBMV. In the study group, the left atrial (LA) impression on the esophagus after a barium swallow was used as a reference of LA silhouette to determine the septal puncture site. In the control group, the LA silhouette under a normal fluoroscopic view was used for the determination of septal puncture site. RESULTS: In the study group, the average length of esophagus impression after a barium swallow was similar to the size of the left atrium measured by angiography (43.8+/-0.6 mm versus 44.1+/-0.7 mm, n=42, P>0.05). The success rate of atrial septum puncture in the study and control groups were 100% and 64.3%, respectively (P<0.01). Transseptal catheterization was subsequently achieved using the barium swallow approach in the 15 initially unsuccessful patients from the control group. PBMV was successful in the 84 patients with significant reduction in LA pressure and improvement of clinical symptoms. CONCLUSIONS: Transseptal catheterization in patients undergoing PBMV can be safely and effectively performed using the barium swallow approach.

Adult↗
PubMed2002

Acute myocardial infarction and congestive heart failure following a blunt chest trauma.

A 42-year-old man experienced chest discomfort after being struck by a low-speed flying object. Two weeks after the accident, the patient complained of severe shortness of breath accompanied by ankle edema. Chest X-ray indicated acute pulmonary edema and left ventricular enlargement. There were Q waves and flat T waves in the precordial ECG leads. Echocardiography revealed dyskinesis in the interventricular septum, hypokinesis in the anterior left ventricular wall, and severe impairment of left ventricular function. A coronary angiogram showed 90% stenosis of the proximal left descending coronary artery. Subsequent medical therapy with diuretics and enalapril led to significant improvement in ventricular function and the patient's symptoms. We conclude that a mild blunt chest trauma can cause myocardial infarction and severe congestive heart failure. Careful investigations into myocardial ischemia or infarction and a close follow-up should be conducted in all patients presenting with a blunt chest trauma.

Adult↗
PubMed2002

Percutaneous balloon angioplasty of inferior vena cava in Budd-Chiari syndrome-R1.

This study was to evaluate the clinical effects of percutaneous balloon angioplasty of Budd-Chiari syndrome (BCS) caused by inferior vena cava (IVC) obstruction. Between 1993 and 1999, 28 men and 14 women with mean age of 44+/-12 years underwent percutaneous balloon angioplasty for primary BCS. Color Doppler ultrasound and venography showed membranous and segmental obstruction of IVC in 29 and 13 patients, respectively. Fourteen patients also had left- and/or mid-hepatic vein obstruction. Angioplasty of IVC was successful in 41 patients (97.6%), resulting in a reduction of pressure gradient between IVC and the right atrium from 15.0+/-2.5 to 5.5+/-0.8 mmHg (P<0.01). A stent was placed in the site of obstruction in the patient with unsuccessful balloon angioplasty. Patients with successful angioplasty or stent placement had significant improvement in clinical symptoms indicated by a reduction in hepatomegaly and the degree of ascites. No specific attempt was made to treat the occluded left- and/or mid-hepatic vein due to the presence of potent right hepatic vein. Over the follow-up period of 32+/-12 months, restenosis of IVC occurred in only one patient (2.4%), which was redilated successfully. Percutaneous balloon angioplasty is a safe and effective therapy for Budd-Chiari syndrome caused by IVC obstruction, therefore should be the first choice of treatment for this condition.

Adolescent↗