Fifty-one consecutive patients underwent modified catheter-mediated direct-current ablation of accessory pathways. Energy was delivered through the distal pair of electrodes (dual electrode configuration) of a 6F quadripolar catheter to the internal surface of the right or left atrioventricular (AV) annulus. In an attempt to prevent the later resumption of accessory pathway conduction, one additional shock was given after the initial successful interruption of accessory pathways. A mean of 2.7 shocks wth cumulative energy of 453±32 Joules/patient interrupted the accessory pathways in 47 patients and modified the accessory pathway conduction in 2 patients. Forty-eight patients were asymptomatic and free of any antiarrhythmic agents with a follow-up ranging from 3-20 months (mean 12±1 months), without early or late serious complications (AV block or tamponade). Conduction characteristics, concealed or manifest, and recording of accessory pathway activity did not affect the outcome. Mean cumulative energy and number of applications of energy to achieve a successful outcome were lower in patients with concealed (376±31 Joules, 2.4±0.2 shocks) than manifest accessory pathways (516±50 Joules, 2.9±0.2 shocks). At the successful ablation sites, the mean shortest retrograde ventriculoatrial interval during orthodromic reentrant tachycardia (VA') was 80±3msec (78% had VA' less than 90msec) and was not different between concealed and manifest accessory pathways; the mean shortest antegrade AV interval was 47±3msec in manifest preexcitation; the mean ratio of atrial to ventricular wave amplitude was not significantly different between left-sided (0.8±0.1) and right-sided (1.1±0.2) accessory pathways (p>0.05). A successful outcome was achieved in 94% of 51 patients. This procedure is relatively safe and effective, regardless of the location of the accessory pathway.
Although erythromycin frequently induces long QT interval and torsade de pointes, the newer drug, azithromycin, has rarely been reported to be associated with torsade de pointes. We report here the occurrence of a significant typical QT prolongation within a few hours after taking azithromycin which lead to torsade de pointes.
To evaluate and compare the safety and efficacy of catheter-mediated direct current (DC) or radio frequency (RF) ablation in patients with free wall accessory atrioventricular pathways, 89 patients with free wall accessory atrioventricular pathway (AP)-mediated tachyarrhythmias underwent catheter ablation. Electrophysiological parameters were similar in the patients with DC (group I, 29 patients with 30 APs) or RF (group II, 60 patients with 64 APs) ablation. Immediately after ablation, it was seen that 27 of 30 APs (90%) had been ablated successfully with DC, but two ofthe 27 APs hadearly return of conduction and received a second ablation session; three of eight APs (38%) and 53 of 56 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 eight A Ps who had a failed RF ablation later had a successful DC ablation. During the follow-up (group I, 14 to 27; group II, 8 to 14 months), all successfully ablated patients had no recurrence of tachycardia. Complications in DC ablation included transient hypotension (two patients), and pulmonary air-trapping (two patients); in RF ablation the complications included cardiac tamponade (I patient) and suspicious aortic dissection (1 patient); myocardial injury (reflected by peak CK-MB, 34 ±5 vs 15 ±4 IU . I−1) and pro-arrhythmic effects (new atrial and ventricular arrhythmias) were more severe in those who had DC ablation. Procedure and radiation exposure time were significantly longer in RF ablation (DC, 3·6 ±0·2 h, 34±4 min; RF4·0±0·4 h, 46±10 min). This study confirms that RF ablation with a large-tip electrode catheter is an effective and relatively safe non-surgical method for treatment of free wall accessory atrioventricular pathway-mediated tachyarrhythmias.
A 17-year-old girl was admitted to our hospital due to traumatic subarachnoid hemorrhage (SAH) and intracerebral hemorrhage (ICH) caused by a traffic accident. On day 6 after admission, significant ST elevation from V1-V3 was observed on 12-lead electrocardiogram (ECG). Acute anterior myocardial inf
Conventional His-bundle ablation, performed at the site with the largest His-bundle potential, displays a high incidence of a new right bundle branch block with loss of pacemaker escape. Damage to the perinodal atrial area may decrease the injury to the His-bundle, such that the escape pacemaker activity with a narrow QRS complex is produced. This study reports data from 25 patients with drug-refractory atrial tachyarrhythmias. Nine patients (group I) received radiofrequency (RF) ablation of the atrioventricular junction (AVJ). General anesthesia was not necessary in group I patients. During a mean follow-up period of 10 months, a complete AV block persisted in 5 patients, and a first degree AV block persisted in 2 patients; these patients were asymptomatic and did not require treatment with antiarrhythmic agents. A successful direct-current (DC) ablation was performed in one of the patients with an unsuccessful RF lesion, producing a new right bundle branch block (RBBB). Sixteen patients (group II) received DC ablation of the AVJ. During a mean follow-up period of 20 months, a complete AV block persisted in 9 patients, a first degree AV block was produced in 7 patients, and a new RBBB occurred in 2 patients. Fifteen patients (94%) were asymptomatic without administration of antiarrhythmic agents. Complications, including nonsustained ventricular tachycardia (1 patient) and pericarditis (1 patient), occurred immediately after ablation in group II. Myocardial injury, reflected by creatine kinase-MB isoenzyme, was higher in group II than in group I (25±2 vs 10±1 IU/l). We conclude that (1) catheter-mediated RF ablation of the AV junction is safer than DC ablation, (2) a majority of patients with drug-refractory atrial tachyarrhythmias can be successfully treated with RF ablation and (3) failure to achieve AV junction ablation with RF does not mitigate against successful application of DC ablation.
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 anguJation 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 transseptai 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.
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