Transseptal approach for catheter ablation of left-sided accessory pathways in children with Marfan syndrome:A case report

BACKGROUND Left-sided accessory pathways(APs)can be accessed with either a transaortic(TA)or transseptal approach(TS).For children with Marfan syndrome(MFS)who have aortic disease,the use of TA can aggravate the disease,making TS the best choice for these patients.CASE SUMMARY A 10-year-old girl was hospitalized because of intermittent heart palpitations and chest tightness.She was diagnosed with MFS,supraventricular tachycardia,Wolff-Parkinson-White syndrome,and left-sided AP was detected by cardiac electrophysiological.Catheter ablation was successfully performed via TS under the guidance of the Ensite system.During the follow-up,no recurrence or complications occurred.CONCLUSION The TS for catheter ablation of left-sided APs can be considered in children with MFS.Adequate evaluation and selection of the appropriate puncture site are particularly important.

3D Non-Fluoroscopic Cryoablation of Right-Sided Accessory Pathways in Children:Monocentric Study and Literature Review

Background:Cryoablation of accessory pathways(APs)is effective and very safe in children,as previously reported by our group.The aim of this retrospective study was to evaluate the current efficacy of 3D non-fluoroscopic cryoablation of right sided APs in children,comparing results obtained with the Ensite VelocityTM and the more recent Ensite PrecisionTM 3D mapping systems.Methods and Results:From January 2016 to December 2019,102 pediatric patients[mean age 12.5±2.8,62 males(61%of total cohort)]with right APs underwent 3D non-fluoroscopic transcatheter cryoablation at our Institution.Fifteen(14.7%)patients had previously undergone catheter ablation.Acute procedural success rate was 95.1%(n=97).No significant differences were detected in acute success rates achieved with Ensite Velocity^(TM)or Ensite PrecisionTM systems nor between manifest(94%)and concealed APs(100%).No permanent complications occurred.During follow-up(428±286 days,median 396 days[interquartile range 179-713]),19 patients(19.6%)had recurrences.Recurrences were more frequent for parahissian/anterior APs compared to midseptal/posterior and lateral APs(p=0.043).Recurrences were not related to the Ensite system used.A redo ablation procedure was attempted in 13 cases,11 cryoablation and 2 radiofrequency ablations:the former was successful in 10 cases out of 11(90.9%).Conclusion:3D cryoablation of right-sided APs is associated with a very high acute success rate with limited use of fluoroscopy,resulting in great benefit to the children.Recurrence rates are not high and patients can be retreated with cryo-energy with higher success rates.

Effect of Accessory Pathway Conduction on PJ Interval in Wolff-Parkinson-White Syndrome

Objective To observe the effect of accessory pathway (AP) conduction on PJ interval in patients with Wolff-Parkinson-White syndrome. Methods 129 patients with a single manifestation of AP who underwent successful radiofrequency ablation (RFCA) were included. Patients were divided into 10 groups according to AP location. The PR intervals, QRS durations and the PJ intervals were measured using simultaneous 12-lead ECG before and after ablation. The PJ intervals before ablation were compared with that after ablation. The atrioventricular (AV) conduction time via atrioventricular node-His conduction system before ablation were compared with the PR intervals after ablation. The ventricular depolarization time via atrioventricular node-His conduction system before ablation were compared with the QRS durations after ablation. Delta waves were compared between each two groups. Results (1) The PJ intervals of right posterior (RP) group and right posteroseptal (RPS) group before ablation were shorter than that after ablation (RP group 226±18 ms vs 236±19 ms, P<0.01, RPS group 221±18 ms vs 238±31 ms, P<0.05, respectively). (2) There were no significant differences between the atrioventricular (AV) conduction time via atrioventricular node-His conduction system before ablation and the PR intervals after ablation. (3)The ventricular depolarization time via atrioventricular node-His conduction system of RP group and RPS group before ablation were shorter than the PR intervals after ablation(RP group 79±12 ms vs 87±9 ms, P=0.01; RPS group 70±13 ms vs 86±9 ms, P<0.05, respectively). (4)The delta waves of RP group and RPS group were longer than that of left posterior group and left posteroseptal group(P<0.05). Conclusion PJ interval is shortened by AP conduction which pre-excites the general last excited part of left ventricle. It is determined by AP location and the extent of preexcitation.

The Experience of Radiofrequency Ablation for Treatment of Multiple Accessory Pathways

Objective To analyse retrospectively the experience of radiofrequency ablation for successful treatment of multiple accessory pathways (APS). Methods 150 patients with supraventricu-lar tachycardia related to APS have undergone radiofrequency ablation since 1994; the data was analysed. Results 8 patients with multiple APS were cured, 4 patients could be diagnosed to have multiple APS during electrophysiologic study (EPS) before ablation, and in the remaining 4 patients the multiple APS could only be diagnosed after successful ablation of one AP. Conclusion right - sided multiple APS are sometimes very difficult to treat by ablation, because there are no standard reference electrograms for bracketing the earliest site. Mapping area should be broader rather than limited by preestablished idea.

Localization and radiofrequency ablation of slow conducting pathway in left free wall

Objectives To study the Electrophysiologic characteristics and method of radiofrequency ablation in patients with slow conduction in left free wall. Methods When 5 cases induced tachycardia, using VS_2 program stimulation terminated the tachycardia to establish that ventricle is the part of reentry circle. Results No retrograde A waves in 4 cases but only 1 case present A wave in terminating tachycardia. The accessory pathways have decreasing conduction in One case. Successful ablation were located in ventricle sides. Conclusions Ventricular sense and S_2 program stimulation to terminate tachycardia is a reliable method to different atrial tachycardia . A wave of successful targets ahead of A wave of any coronary sinus leads is 8～22 ms.

Dyssynchrony Induced by Ventricular Preexcitation: A Risk Factor for the Development of Dilated Cardiomyopathy

Background:Signifi cant left ventricular dysfunction may arise in right-sided accessory pathways with ventricular preexcitation in the absence of recurrent or incessant tachycardia.This has just been realized and not enough attention has been paid to it.Methods:In the last 7 years,we identifi ed 12 consecutive children with a diagnosis of ventricular preexcitation–induced dilated cardiomyopathy.This report describes the clinical and echocardiographic characteristics of the patients before and after ablation.Results:Dyssynchronous ventricular contraction was observed by M-mode echocardiography and two-dimensional strain analysis in all patients.The basal and middle segments of the interventricular septum became thin and moved similarly to an aneurysm,with typical bulging during the end of systole.The locations of the accessory pathways were the right-sided septum(n=5)and the free wall(n=7).Left ventricular synchrony was obtained shortly after ablation.The left ventricular function recovered to normal and the left ventricular end-diastolic diameter decreased gradually during follow-up.Conclusions:A causal relationship between ventricular preexcitation and the development of dilated cardiomyopathy is supported by the complete recovery of left ventricular function and reversed left ventricular remodeling after the loss of ventricular preexcitation.Preexcitation-related dyssynchrony was thought to be the crucial mechanism.Ventricular preexcitation–induced dilated cardiomyopathy is an indication for ablation with a good prognosis.