Biomedical subjects

C W Chiou

Publications and source records attributed to C W Chiou.

61 records · Page 4Linked to original sources

PubMed1993

Serial electrophysiological studies in the late outcome of radiofrequency ablation for accessory atrioventricular pathway-mediated tachyarrhythmias.

Assessment of radiofrequency ablation for accessory pathway-mediated tachyarrhythmias is evaluated by a variety of methods in different institutes. However, the predictive values of these methods are not known. Therefore, serial electrocardiograms (12-lead, 24-h Holter monitoring), reviews of symptoms, and electrophysiological studies (immediate, early, late) were used in this institute to evaluate and predict late outcome in 150 patients with 174 accessory pathways. Late electrophysiological study (130 +/- 11 days after ablation) detected a larger proportion of patients (11.1%) with late ablation failure than immediate (1.3%), or early (7.0%) electrophysiological study, or serial electrocardiograms (1.4%), or reviews of symptoms (1.4%); it showed that patients with concealed accessory pathways (11.4%), energy delivered to the ventricular sites of left concealed accessory pathways (23.3%), and those without a recordable accessory pathway activation potential (14.8%) had a higher incidence of recurrent conduction, and also provided the most accurate information for predicting late outcome with higher sensitivity (100%) and predictive accuracy (100%) than other tests. It is concluded that the value of serial electrocardiograms, symptom review, immediate and early electrophysiological studies should be downgraded, and that the late electrophysiological study has a high predictive value for late outcome and helps understanding of the residual changes in accessory pathways after initially successful ablation.

Adolescent↗

PubMed1993

Radiofrequency ablation of left-sided accessory atrioventricular pathways in patients with unusual coronary sinus.

Four patients with left-sided accessory pathways (APs) and unusual coronary sinus (CS) received radiofrequency ablation. Unusual CS included occlusion of CS (patient 1), acute angulation of proximal CS (patients 2 and 3), and narrowing of CS orifice and proximal segment (patient 4). CS catheterization and AP mapping along the CS could not be performed in the four patients. Radiofrequency ablation by left ventricular retrograde technique for the manifest left posteroseptal AP (patient 1), concealed left posterior AP (patient 2), and transseptal left atrial technique for the manifest left posteroseptal AP (patient 3) and manifest left posterior AP (patient 4) were performed successfully without CS catheter guidance. This study suggests that radiofrequency ablation of left-sided AP with unusual CS is feasible by some special techniques.

Adult↗

PubMed1992

Comparison of direct-current and radiofrequency ablation of free wall accessory atrioventricular pathways in the Wolff-Parkinson-White syndrome.

To evaluate and compare the safety and efficacy of catheter-mediated direct-current (DC) or radiofrequency (RF) ablation in patients with free wall accessory atrioventricular pathways, 95 patients with free wall accessory atrioventricular pathway-mediated tachyarrhythmias underwent catheter ablation. Immediately after ablation, 27 of 30 accessory pathways (90%) were ablated successfully with DC, but 2 of the 27 had early return of conduction and received a second ablation session; 3 of 8 (38%) and 57 of 62 (92%) accessory pathways were ablated successfully with RF through a small-tip (2 mm) and a large-tip (4 mm) electrode catheter, respectively. Complications in DC ablation included transient hypotension (2 patients) and pulmonary air-trapping (2 patients) and in RF ablation, cardiac tamponade (1 patient) and suspicious aortic dissection (1 patient); myocardial injury and proarrhythmic effects were more severe in DC ablation. Procedure and radiation exposure time were significantly longer in RF ablation (DC, 3.6 +/- 0.2 hours, 34 +/- 4 minutes; RF 4.2 +/- 0.5 hours, 50 +/- 10 minutes). This study confirms that RF ablation is associated with little morbidity and few complications, and RF ablation with a large-tip electrode catheter is an effective and relatively safe nonsurgical method for treatment of free wall accessory atrioventricular pathway-mediated tachyarrhythmias.

Adult↗

PubMed1992

Radiofrequency catheter ablation for treatment of Wolff-Parkinson-White syndrome--short- and long-term follow-up.

One hundred and twenty-five patients with accessory pathways mediated tachyarrhythmias underwent radiofrequency ablation. Right-sided accessory pathways were ablated from the atrial aspect of the tricuspid anulus (all from the femoral vein approach) and the left-sided accessory pathways were ablated from the atrial or ventricular aspect of the mitral anulus. Immediately after the procedures, 3 of 8 accessory pathways (38%) and 131 of 137 accessory pathways (95%) were ablated successfully with radiofrequency through a small-tip (2 mm) and a large-tip (4 mm) electrode catheter, respectively. Seven of the 11 accessory pathways that failed radiofrequency ablation had a later successful direct current ablation. During follow-up (3 to 22 months), serial electrophysiological study showed that 11 of the 114 patients (10%) with successful ablation had return of accessory pathway conduction (2 had recurrence of tachycardia, 2%). Complications included accidental AV block (1 patient), cardiac tamponade (1 patient) and possible aortic dissection (1 patient). Transient proarrhythmic effects (more atrial and ventricular premature beats) were seen during the first week and sustained ventricular tachyarrhythmias were not inducible. In a successful session, procedure and radiation exposure times (including the time for diagnostic procedures) were 3.8 +/- 0.2 h and 45 +/- 4 min, respectively. This study confirms that radiofrequency ablation with a large-tip electrode catheter is an effective and relatively safe nonsurgical method for treatment of Wolff-Parkinson-White syndrome, with a low complication and recurrence rate.

Adult↗

PubMed1992

Radiofrequency ablation of bilateral quadruple accessory pathways in a patient with Wolff-Parkinson-White syndrome.

A patient with drug refractory supraventricular tachycardia showed electrophysiological evidence of bilateral quadruple accessory pathways. The conduction was bidirectional in the left posteroseptal and left posterolateral accessory pathways, antegrade in the right lateral accessory pathway, and retrograde in the right anterior accessory pathway. The four pathways participated in seven types of reciprocating tachycardias. Radiofrequency ablation eliminated the four pathways successfully. The patient was asymptomatic and free of any drug during a 10-month follow-up.

Adult↗

PubMed1992

Reappraisal of intermediate-term follow-up of radiofrequency ablation of accessory atrioventricular pathways for treatment of Wolff-Parkinson-White syndrome.

To evaluate the safety and efficacy of catheter mediated radiofrequency (RF) ablation in patients with Wolff-Parkinson-White syndrome, 125 patients with accessory pathway (AP) mediated tachyarrhythmias underwent RF ablation. Right-sided APs were ablated from the atrial aspect of the tricuspid annulus (all from the femoral vein approach) and the left-sided APs were ablated from the atrial or ventricular aspect of the mitral annulus. Immediately after ablation, 3 of 8 APs (38%) and 131 of 137 APs (95%) were ablated successfully with RF through a small-tip (2 mm) and a large-tip (4 mm) electrode catheter, respectively. Seven of the 11 APs where RF ablation failed had a later successful DC ablation. During follow-up (3 to 22 months), 11 of the 114 patients (10%) with successful ablation had return of accessory pathway conduction (2 had recurrence of tachycardia (2%)). Complications included transient myocardial injury (peak CK-MB 15 +/- 3 IU/l), transient proarrhythmic effects (more atrial and ventricular premature beats), accidental AV block (1 patient), cardiac tamponade (1 patient) and suspicion of aortic dissection (1 patient). In successful sessions, procedure and radiation exposure time were 3.8 +/- 0.2 h and 45 +/- 4 min, respectively. This study confirms that RF ablation with a large-tip electrode catheter is an effective and relatively safe nonsurgical method for treatment of Wolff-Parkinson-White syndrome.

Adult↗

PubMedDate not supplied

Electropharmacologic characteristics and radiofrequency catheter ablation of sustained ventricular tachycardia in patients without structural heart disease.

Twenty-six patients (mean age 39 +/- 17 years) with idiopathic sustained ventricular tachycardia (VT) were included for study. The patients were divided into two groups: group I: 14 patients with VT originating from the right ventricular outflow tract (wide QRS tachycardia with complete left bundle branch block pattern), and group II: 12 patients with VT originating from the left ventricle (wide QRS tachycardia with complete right bundle branch block pattern). Most of the group I patients (11/14) needed isoproterenol to facilitate induction of VT, and were sensitive to both verapamil and adenosine. Eight patients had successful radio-frequency (RF) ablation and were free of VT without any antiarrhythmic drugs. In group II, sustained VT was induced by programmed ventricular stimulation in all the patients (only 3 patients needed isoproterenol for facilitation); verapamil could terminate all the VT but none of the patients responded to adenosine. Eight patients received RF ablation and 6 patients had successful ablation without recurrent tachycardia on a long-term basis. Different sensitivity to adenosine and isoproterenol between right and left ventricular idiopathic VT suggested different underlying mechanisms for both types of VT. The patients who did not receive catheter ablation still had attacks of VT despite antiarrhythmic drug treatment; however, none of these patients had sudden death since the first attack of VT (mean 95 +/- 51 months), suggesting a benign prognosis in idiopathic VT.

Adolescent↗