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Biomedical subjects

Lexin Wang

Publications and source records attributed to Lexin Wang.

45 records · Page 3Linked to original sources
PubMed2002

Predictors of long-term success in catheter ablation of atrioventricular nodal reentrant tachycardia: a multivariate regression analysis.

BACKGROUND: To investigate the predictors of long-term success after catheter ablation of atrioventricular nodal reentrant tachycardia (AVNRT). METHODS: One-hundred and fourteen consecutive patients underwent slow pathway ablation using anteroseptal (n=24), midseptal (n=65) and posteroseptal approach (n=25). The correlation between ablation approaches, electrophysiological characteristics during and after ablation and the recurrence rate of AVNRT was analyzed by a multivariate regression analysis. RESULTS: During ablation, transient AV block in the anteroseptal, midseptal and posteroseptal approach occurred in 8.3, 4.6 and 0%, respectively (P<0.01). AVNRT recurred in seven patients after 5 years follow-up. Five recurrences (20.8%) were from anteroseptal approach group and two (3.1%) were from midseptal approach group. Multivariate regression analysis revealed that anteroseptal ablation approach and residual dual atrioventricular nodal pathway following apparently successful ablation were the predictors for recurrence of AVNRT (R=0.645, P<0.001). CONCLUSION: Anteroseptal approach of slow pathway ablation is associated with a higher incidence of transient AV block and AVNRT recurrence than other approaches. Residual dual atrioventricular nodal pathway after apparently successful ablation also carries a high risk of recurrence.

Adolescent↗
PubMed2002

Effects of procainamide on transmural ventricular repolarisation.

To investigate the pharmacological effect of procainamide on transmural ventricular repolarisation in normal heart, the transmural activation-recovery intervals (ARI) and their responses to procainamide (20 mg/min i.v. for 20 min) were studied in 6 open-chest, pentobarbitone-anaesthetised sheep. ARI was measured from the unipolar ECGs acquired with 4 plunge needles inserted into the basal and apical parts of the left ventricular wall. During sinus rhythm (cycle length 500-700 ms), there was no significant difference in the pooled ARI between the epicardium (266.0 +/- 30.5 ms), midmyocardium (265.0 +/- 28.9 ms) and endocardium (265.7 +/- 28.1 ms) (p > 0.05). Procainamide prolonged ARI in all myocardial layers. The pooled ARI prolongation from the epicardium, midmyocardium and endocardium of the 6 animals was 66.8 +/- 18.3, 70.3 +/- 14.7 and 65.3 +/- 15.7 ms (p > 0.05), respectively. In conclusion, sodium channel blocker procainamide results in a similar repolarisation prolongation in the left ventricular epicardium, midmyocardium and endocardium of a healthy heart.

Animals↗
PubMed2002

A comparison of metropolitan and rural medical schools in China: which schools provide rural physicians?

To compare the role of metropolitan and rural medical schools in the provision of rural physicians, a survey was conducted in 12 metropolitan and 10 rural medical schools. Rural medical schools enrolled fewer students (P = 0.019), and produced fewer graduates (P = 0.023) than metropolitan medical schools. Students in rural medical schools were mainly from surrounding regional cities and counties, whereas those in metropolitan schools were from cities nationwide (P < 0.001). All rural medical schools produced rural physicians; one rural school reported that of its 256 graduates, 88 (34.4%) entered rural practice. Ten of the 12 metropolitan medical schools did not produce any rural physicians, whereas the remaining two metropolitan schools registered a total of 73 graduates who selected a rural practice location. These results indicate that rural medical schools may play a key role in overcoming the shortage of physicians in rural communities in China.

China↗
PubMed2002

A new approach for transseptal catheterization in patients undergoing percutaneous balloon mitral valvuloplasty.

AIMS: To evaluate the safety and efficacy of a new approach for transseptal catheterization in patients undergoing percutaneous balloon mitral valvuloplasty (PBMV). METHODS: One hundred and two patients with rheumatic mitral stenosis were randomized into two groups. In the study group (RA approach), an imaginary horizontal line was drawn from the top end of the tricuspid valve under anteroposterior fluoroscopic view. The intersection of the horizontal line and the right edge of the corresponding thoracic vertebra was defined as the upper border of the Fossa ovalis. The atrial septum was punctured from a point 0.5 cm below the upper border of the Fossa ovalis. In the control group (LA approach), an imaginary horizontal line was drawn between the upper and middle third of the left atrium, and the intersection of this horizontal line and the right edge of the corresponding thoracic vertebra was used as an atrial septum puncture point. RESULTS: Atrial septum puncture succeeded in all patients in the study group and in 72.6% of the patients in the control group (p < 0.01). The average fluoroscopy times for transseptal catheterization in the study and the control groups were 2.0 +/- 0.5 and 3.0 +/- 1.0 min, respectively (p < 0.01). Transseptal catheterization was subsequently achieved using the RA approach in the 14 patients from the control group in whom the LA approach failed. CONCLUSIONS: The RA approach is a safe and effective means for transseptal catheterization in patients undergoing PBMV.

Cardiac Catheterization↗
PubMedDate not supplied

Radiofrequency catheter ablation of accessory pathway-mediated tachycardia is a safe and effective long-term therapy.

BACKGROUND: The primary purpose of the study was to evaluate long-term clinical results of radiofrequency catheter ablation of accessory pathway-mediated tachycardia. METHODS: Catheter ablation was performed in 321 patients who were subsequently followed up for an average of 36 months. RESULTS: Accessory pathway-mediated tachycardia was abolished by catheter ablation in 308 patients (96%). Right free wall (10.6%) and right posteroseptal (14.9%) accessory pathway was associated with higher failure rate than left-sided pathways (2.3%, p<0.01). Atrioventricular block occurred in two patients during ablation of anteroseptal pathway. Recurrence of accessory pathway conduction occurred in 13 (4.1%) patients, principally within the first 4 weeks after ablation procedure. Recurrence in right free wall (12.8%) or right posteroseptal (14.2%) pathways was higher than in left-sided pathways (1.8%, p<0.01). CONCLUSIONS: Radiofrequency catheter ablation has high immediate success rate and long-term recurrence of accessory pathway conduction or tachycardia. Right free wall or right posteroseptal pathways are associated with higher incidence of initial ablation failure and short- to medium-term recurrence.

Adolescent↗
PubMedDate not supplied

Long-term follow-up of patients with P-R prolongation after catheter ablation of slow pathway for atrioventricular node re-entrant tachycardia.

BACKGROUND: Long-term impact of interval between P wave and R wave (P-R) prolongation on prognosis of patients with successful catheter ablation of slow atrioventricular nodal pathway was investigated. METHODS: Among 436 patients undergoing slow-pathway ablation for atrioventricular node re-entrant tachycardia (AVNRT), 17 (3.9%) experienced permanent P-R prolongation. Ablation target sites where conduction block was induced were located in mid- or anteroseptum. Fast junctional rhythm with ventriculoatrial conduction block was observed in eight patients immediately before atrioventricular block. RESULTS: Antegrade slow-pathway conduction was eliminated in 16 patients, and retrograde fast- and slow-pathway conduction was abolished in all patients. There was no recurrence of AVNRT after an average of 38 +/- 12 month follow-up. There was no deterioration of atrioventricular block in these patients. Average PR interval prior to hospital discharge and at the end of follow-up was 0.24 +/- 0.02 sec and 0.23 +/- 0.02 sec, respectively (p >0.05). Left ventricular ejection fraction remained unchanged in these patients (p >0.05). CONCLUSIONS: Radiofrequency catheter ablation of slow pathway for AVNRT is associated with a small risk of atrioventricular block. PR prolongation after successful slow-pathway ablation is associated with benign prognosis.

Adult↗
PubMedDate not supplied

Long-term efficacy of slow-pathway catheter ablation in patients with documented but noninducible supraventricular tachycardia.

BACKGROUND: The long-term efficacy of radiofrequency catheter ablation of slow pathway in patients with dual atrioventricular node pathway and a documented but noninducible paroxysmal supraventricular tachycardia (PSVT) is not entirely clear. METHODS: Forty nine patients (Group A) with documented but noninducible PSVT and dual atrioventricular node pathway were prospectively studied. Programmed electrical stimulation induced a single atrioventricular node echo beat in 13 patients, and double echo beats in 9 at baseline or during isoproterenol infusion. Clinical and electrophysiological characteristics of Group A patients were compared with that of age- and gender-matched patients with dual atrioventricular node pathway but inducible PSVT (Group B). RESULTS: There was no significant difference in the electrophysiological properties of the fast and slow pathways between the two groups. Catheter ablation eliminated the slow pathway in all patients. There was no recurrence of PSVT in either Group A or Group B during the follow-up of 38 +/- 5 months. CONCLUSIONS: In patients with dual atrioventricular node pathway and a documented but noninducible PSVT, catheter ablation of slow pathway is highly effective in preventing tachycardia in long term.

Adult↗
PubMedDate not supplied

Physician-related barriers to hypertension management.

OBJECTIVE: To investigate the levels of understanding and implementation of current hypertension guidelines among specialist physicians. SUBJECTS AND METHODS: A survey of the understanding and practice in the management of hypertension was conducted among 56 physicians who individually had managed more than 150 new hypertensive patients annually. RESULTS: All respondents were familiar with the current hypertension guidelines and 51.8% always or usually followed these guidelines in treating their patients. Most believed that the lowest blood pressure where pharmacological therapy should be initiated was 155/95 mm Hg. Forty-five (80.4%) physicians considered a blood pressure of less than 140/ 90 mm Hg should be achieved in hypertensive patients. Only 12 (21.4%) respondents provided routine advice on lifestyle modification to their patients. Fifty-four (96.4%) respondents ranked poor adherence to antihypertensive drugs as the major patient barrier to blood pressure control. CONCLUSIONS: Most physicians are familiar with the current hypertension guidelines but the implementation of these guidelines in clinical practice is inadequate. Systematic educational programs are needed to enhance physicians' awareness of the optimal goals of blood pressure control.

Antihypertensive Agents↗