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Aims This study presents and evaluates the impact of a new lowest-dose fluoroscopy protocol (Siemens AG), especially designed for electrophysiology (EP) procedures, on X-ray dose levels. Methods and results From October 2014 to March 2015, 140 patients underwent an EP study on an Artis zee angiography system. The standard low-dose protocol was operated at 23 nGy (fluoroscopy) and at 120 nGy (cine-loop), the new lowest-dose protocol was operated at 8 nGy (fluoroscopy) and at 36 nGy (cine-loop). Procedural data, X-ray times, and doses were analysed in 100 complex left atrial and in 40 standard EP procedures. The resulting dose–area products were 877.9 ± 624.7 µGym² ( n = 50 complex procedures, standard low dose), 199 ± 159.6 µGym² ( n = 50 complex procedures, lowest dose), 387.7 ± 36.0 µGym² ( n = 20 standard procedures, standard low dose), and 90.7 ± 62.3 µGym² ( n = 20 standard procedures, lowest dose), P < 0.01. In the low-dose and lowest-dose groups, procedure times were 132.6 ± 35.7 vs. 126.7 ± 34.7 min ( P = 0.40, complex procedures) and 72.3 ± 20.9 vs. 85.2 ± 44.1 min ( P = 0.24, standard procedures), radiofrequency (RF) times were 53.8 ± 26.1 vs. 50.4 ± 29.4 min ( P = 0.54, complex procedures) and 10.1 ± 9.9 vs. 12.2 ± 14.7 min ( P = 0.60, standard procedures). One complication occurred in the standard low-dose and lowest-dose groups ( P = 1.0). Conclusion The new lowest-dose imaging protocol reduces X-ray dose levels by 77% compared with the currently available standard low-dose protocol. From an operator standpoint, lowest X-ray dose levels create a different, reduced image quality. The new image quality did not significantly affect procedure or RF times and did not result in higher complication rates. Regarding radiological protection, operating at lowest-dose settings should become standard in EP procedures.

Aims In patients with paroxysmal atrial fibrillation (pAF), pulmonary vein isolation (PVI) has become an accepted treatment option with single procedure success rates of 60–80%. A repeat ablation is performed in ∼30% of patients because of arrhythmia recurrence. The strategy for this repeat procedure is not defined. Methods and results Patients with pAF recurrence after PVI were prospectively randomized and underwent a second ablation procedure with either PVI of all reconnected veins or PVI with an additional left atrial anterior line. Follow-up in our arrhythmia clinic was every 3 months up to 12 months including 7 day Holter monitoring. A total of 77 patients (mean age 63 ± 9 years, 69% males) were included in the analysis. A repeat PVI was performed in 41 patients, PVI + anterior line in 36 patients. After a follow-up of 12 months, 26 of 41 (63%) patients after repeat PVI and 18 of 36 (50%) patients with PVI + anterior line were in stable sinus rhythm off antiarrhythmic medication ( P = 0.26). In most patients (12 of 15 patients with PVI and 14 of 18 patients with PVI + anterior line) with an arrhythmia recurrence after the second procedure, the recurring arrhythmia was paroxysmal AF. In 2 of 15 patients of the PVI group and in 4 of 18 patients of the PVI + anterior line group atypical flutter was the reoccurring arrhythmia ( P = NS). Conclusion In this prospective randomized trial, patients with a recurrence of paroxysmal AF had no better outcome after repeat PVI + one left atrial line compared with patients with repeat PVI only.

Aims The modified anterior line (MAL) is an alternative to the mitral isthmus (MI) line for the treatment of perimitral atrial flutter (PMFL). We sought to investigate acute and long-term efficacy of this line if routinely used for PMFL. Methods and results The cohort included 77 consecutive patients who underwent catheter ablation of PMFL. The anterior line was deployed between the anterolateral mitral annulus and the ostium of the left superior pulmonary vein. Perimitral atrial flutter was either the presenting arrhythmia after persistent atrial fibrillation (AF) ablation (Group 1, n = 42, 54.5%), occurring during AF ablation (Group 2, n = 25, 35%) or presenting as primary arrhythmia (Group 3, n = 8, 10%). Acute success was defined as PMFL termination during MAL deployment with demonstration of bidirectional line block. Acute success was achieved in 68 of 77 patients (88%) without difference between the three groups. In five patients an additional MI line was necessary to terminate PMFL and in four patients both lines failed to achieve termination. During follow-up (16 ± 7 months), 38 of 77 (49%) patients underwent a repeat procedure for a recurrent arrhythmia. During reablation, 13 of 38 (34%) patients were identified to have a PMFL recurrence. Persistent MAL block was demonstrated in 22 of 38 (58%) patients during the repeat ablation. Conclusion The MAL is effective for acute and long-term treatment of PMFL. Maintenance of bidirectional MAL block was shown in 58% of patients during a repeat ablation.

Aims Data about the long-term outcome after cryoablation for atrioventricular nodal reentrant tachycardia (AVNRT) in the paediatric population indicate that recurrence rates are higher with cryo than with radiofrequency energy (RF). The purpose of this study was to review our institutional long-term outcome after cryoablation for AVNRT and to seek for predictors of recurrence. Methods and results Forty-nine patients (28 female, age 14 ± 2.7 years) undergoing slow-pathway modulation or ablation for AVNRT at our institution from 2004 to 2008 were included in the study. Acute success was obtained in all patients (100%) with a mean procedure time of 164 ± 50 min and a mean fluoroscopy time of 13 ± 8 min. During a follow-up time of 30 ± 1.9 months, AVNRT recurrence occurred in 11/49 patients (22.4%). Age, sex, number of cryomappings or ablations, catheter tip (4 mm vs. 6 mm), or ablation endpoint (slow-pathway ablation vs. modulation) were not predictive for recurrence. In eight patients, reablation using cryo was performed. All these patients remained free of arrhythmia symptoms during a follow-up of 30 ± 8 months following the second procedure. Conclusion Although cryoablation for the treatment for AVNRT in paediatric and adolescent patients is safe and associated with a high acute success rate, AVNRT recurrence occurs in 22% of patients during long-term follow-up without identifiable predictors for recurrence. A second cryoablation procedure leads to a success rate of 100% during long-term follow-up.

Aims Syncope in Wolff–Parkinson–White (WPW) syndrome may reveal an arrhythmic event or is not WPW syndrome related. The aim of the study is to evaluate the results of electrophysiological study in WPW syndrome according to the presence or not of syncope and the possible causes of syncope. Methods and results Among 518 consecutive patients with diagnosis of WPW syndrome, 71 patients, mean age 34.5+ 17, presented syncope. Transoesophageal electrophysiological study in control state and after isoproterenol infusion was performed in the out-patient clinic. Atrioventricular re-entrant tachycardia (AVRT) was more frequently induced than in asymptomatic patients (n ¼ 38, 53.5%, P , 0.01), less frequently than in those with tachycardia; atrial fibrillation (AF) and/or antidromic tachycardia (ATD) was induced in 28 patients (39%) more frequently (P , 0.05) than in asymptomatic patients or those with tachycardia. The incidence of high-risk form [rapid conduction over accessory pathway (AP) and AF or ATD induction] was higher in syncope group (n ¼ 18, 25%, P , 0.001) than in asymptomatic subjects (8%) or those with tachycardias (7.5%). Maximal rate conducted over AP was similar in patients with and without syncope, and higher in patients with spontaneous AF, but without syncope. Results were not age-related. Conclusion Tachycardia inducibility was higher in patients with syncope than in the asymptomatic group. The incidence of malignant WPW syndrome was higher in patients with syncope than in asymptomatic or symptomatic population, but the maximal rate conducted over AP was not higher and another mechanism could be also implicated in the mechanism of syncope.

Aims To determine the feasibility and the results of exercise testing (ET) and electrophysiological study (EPS) in outpatient asymptomatic children with a Wolff-Parkinson-White (WPW) syndrome. Methods and results Exercise testing and transesophageal EPS were performed in 55 outpatient asymptomatic children aged 6 to 19 years old (14 ± 3) with WPW. Wolff-Parkinson-White persisted during maximal exercise. Isoproterenol was not required in five children younger than 10 years old, because they developed a catecholaminergic sinus tachycardia. Maximal rate conducted through accessory pathway (AP) was higher in children younger than 16 years old than in teenagers ( P < 0.05). Atrioventricular re-entrant tachycardia (AVRT) was induced in six children; atrial fibrillation (AF) in 12 children. The induction of tachycardias and the dangerous forms (18%) were not influenced by age. After 5 ± 1 years, one child, 12 year old with inducible rapid AF, had a sudden cardiac arrest; two children became symptomatic after ablation. Conclusions Transesophageal EPS was required to determine the prognosis of asymptomatic WPW in children. The maximal rate conducted in AP was higher in children younger than 16 years old than in teenagers; other data did not differ. AVRT was rare; 71% of children had no inducible arrhythmia and were authorized to resume physical activities.