Coronary sinus stenosis as a late complication of catheter ablation in Wolff-Parkinson-White syndrome

Successful implantation of a coronary sinus lead after stenting of a coronary vein stenosis

Dislodgment of the coronary sinus lead was observed in a 79-year-old patient 8 months after implantation of a biventricular pacing system. A severe stenosis in the posterolateral branch, in which the lead was previously positioned, prohibited reinsertion of the lead. Because no other branches with adequate anatomy for lead insertion were available in the targeted area, the stenosis was dilated and stented. Subsequently, the left ventricular lead could be reimplanted in the same vessel.

Radiofrequency catheter ablation of left-sided accessory pathways in pediatric patients

In many cases, radiofrequency catheter ablation has replaced the long-term use of antiarrhythmic medication for symptomatic tachycardia, and has all but eliminated arrhythmia surgery. The most common substrate for radiofrequency catheter ablation in pediatric patients is atrioventricular (AV) reentry tachycardia due to a concealed or manifest accessory pathway. Accessory pathways are distributed unevenly along the right and left atrioventricular valve annuli, and left-sided accessory pathways are most common. Although some centers advocate an abbreviated diagnostic and mapping approach to both concealed and manifest left-sided accessory pathways, most still use a complete electrophysiological evaluation and complex catheter manipulation for mapping, followed by the application of radiofrequency energy. Left-sided accessory pathways may be approached from the transatrial approach, the retrograde aortic approach, or less commonly from within the coronary sinus. Each approach has proven to be associated with success, but also with a distinct set of risks. Possibly because left-sided accessory pathways are most common, catheter ablation of this substrate has proven highly successful and has the lowest risk of recurrence. However, recent data also suggest that this substrate is associated with greater risk of complications than of right-sided accessory pathways or pathways located in the posteroseptal region. The following report reviews some of the recently described diagnostic and mapping techniques, success rates, risks and follow-up data in pediatric patients undergoing radiofrequency catheter ablation of left-sided accessory pathways.

Case report: pulmonary vein stenosis following RF ablation of paroxysmal atrial fibrillation: successful treatment with balloon dilation

Paroxysmal atrial fibrillation and atrial tachycardia may originate from a focal source in one or multiple pulmonary veins. A focal origin facilitates a potential cure amendable to radiofrequency ablation. Herein we report the case of a 16 year old adolescent male with a tachycardia induced cardiomyopathy who presented with very frequent paroxysmal episodes of atrial fibrillation, atrial flutter and atrial tachycardia. The origin of the arrhythmia was mapped to the secondary branches of the left lower pulmonary vein using an octapolar micro-mapping catheter. Immediately following application of three radiofrequency lesions, angiography of the left lower pulmonary vein revealed a region of focal stenosis at the site of energy application, with delayed pulmonary venous emptying. Attempts to relieve any element of spasm using direct administration of nitroglycerin were unsuccessful. Three months later repeat catheterization revealed an unchanged region of tight anatomical stenosis. Balloon dilation of two stenotic areas resulted in dramatic relief of the obstruction and improved venous drainage. Recatheterization 6 months later revealed mild restenosis that was successfully redilated. Intracardiac ultrasound demonstrated focal constriction. Care should be exercised in attempting RF ablation in distal arborization sites of the pulmonary veins in children, because of the small caliber compared to adult subjects. Radiofrequency induced focal areas of stenosis may be amenable to balloon catheter dilation.

Efficacy and safety of an irrigated-tip catheter for the ablation of accessory pathways resistant to conventional radiofrequency ablation

BACKGROUND

Radiofrequency catheter ablation of accessory pathways (APs) is very effective in all but a minority of patients. We examined the usefulness and safety of irrigated-tip catheters in treating patients with APs resistant to conventional catheter ablation.

METHODS AND RESULTS

Among 314 APs in 301 consecutive patients, conventional ablation failed to eliminate AP conduction in 18 APs in 18 patients (5.7%), 6 of which were located in the left free wall, 5 in the middle/posterior-septal space, and 7 inside the coronary sinus (CS) or its tributaries. Irrigated-tip catheter ablation was subsequently performed with temperature control mode (target temperature, 50 degrees C), a moderate saline flow rate (17 mL/min), and a power limit of 50 W (outside CS) or 20 to 30 W (inside CS) at previously resistant sites. Seventeen of the 18 resistant APs (94%) were successfully ablated with a median of 3 applications using irrigated-tip catheters. A significant increase in power delivery was achieved (20.3+/-11.5 versus 36.5+/-8.2 W; P:<0.01) with irrigated-tip catheters, irrespective of the AP location, particularly inside the CS or its tributaries. No serious complications occurred.

CONCLUSIONS

Irrigated-tip catheter ablation is safe and effective in eliminating AP conduction resistant to conventional catheters, irrespective of the location.