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Background: The study sought to evaluate whether electrogram-aided identification of hot spot targets produces additional clinical and/or procedure benefits when using a non-traditional focal cryo ablation method to treat common atrial flutter., Methods: A preliminary study identified a specific electrogram criterion (e.g., a stimulus to onset of electrogram time of 74 [+/- 5] ms) that produced successful cryo testing plus subsequent cryoablation with demonstrable bi-directional isthmus block created at intervention site. In the present study, 26 consecutive patients with symptomatic common atrial flutter were ablated with a 9FR 8 mm tip cryo catheter using electrogram-aided identification of hot spot targets with a stimulus to onset of electrogram time of > or =70 ms. Outcomes measured were bi-directional isthmus block at intervention, symptom and conduction recurrence at 3 month follow-up, symptom recurrence at 6 month follow-up, and procedure characteristics., Results: Acute success rate at intervention was 100%. The percentage of patients with symptom recurrence by 3 month follow-up was 4.5% and no additional patients had arrhythmia symptoms documented by 12 month follow-up. Repeat electrophysiological study (EPS) at 3 month follow-up identified 44% of patients with conduction recurrence. The mean +/- SD number of cryo tests and ablations were 11 +/- 9 and 2 +/- 1, respectively. Procedure, fluoroscopy and cryoapplication times were 77 +/- 29 min, 11 +/- 7 min, and 28 +/- 11 min, respectively., Conclusions: A high acute success rate, plus low long-term clinical recurrence rate and procedure benefits may be achieved with electrogram-aided identification of hot spots for focal cryo ablation treatment of common atrial flutter using a 9FR 8 mm tip cryo catheter. The population of patients who were asymptomatic and had demonstrated conduction recurrence on repeat EPS at 3 month follow-up require close scrutiny over the long-term to ascertain whether they eventually experience arrhythmic symptoms. However, should these patients remain symptom-free over the long-term it would suggest that the entire isthmus may not be needed to support symptomatic common atrial flutter.

Background: Larger tipped cryothermal catheters may deliver efficacy and procedure benefits in the treatment of patients with atrial flutter., Objective: To compare 7 French 6 mm and 9 French 8 mm tip cryothermal catheters (Freezor, Xtra or Freezor, MAX, CryoCath Technologies Inc., Kirkland, Canada) in terms of acute and chronic efficacy, and procedure characteristics in the treatment of atrial flutter., Methods: This non-randomized clinical investigation determined bi-directional isthmus block at intervention, procedure characteristics, and symptom and conduction recurrence rates post procedure in consecutive patients with symptomatic atrial flutter ablated either with the 7 French 6 mm tip cryothermal catheter (n = 43) at -75 degrees C for 4 minutes or the 9 French 8 mm tip cryothermal catheter (n = 51) at -75 degrees C for 8 minutes., Results: Clinical data showed a higher acute success rate for the larger tipped catheter (100% vs. 88%). Symptom recurrence rates were 0% for both catheters at 3, 6, and 9 month follow-up. Conduction recurrence rates were similar for both catheters on repeat electrophysiological study at 3 months post procedure (35% vs. 32%). Procedure benefits were fewer cryotests (20 +/- 17 vs. 26 +/- 21) and ablations (4 +/- 4 vs. 12 +/- 18), and shorter procedure (80 +/- 61 min vs. 87 +/- 48 min), fluoroscopy (14 +/- 9 min vs. 24 +/- 10 min), and cryoapplication times (37 +/- 18 min vs. 44 +/- 23 min) with the larger tipped catheter. There were no adverse events reported., Conclusions: Clinical results showed differences in catheter performance that favoured the larger tipped catheter. However, increased acute success rate did not translate into reduced conduction recurrence rate post ablation, although clinical recurrence was completely absent long-term.

Introduction: At the present time, several techniques are used or are under investigation for atrial fibrillation (AF) therapy. Nowadays, no well-defined target for such therapies has been yet completely identified. Furthermore, AF is an arrhythmia with high rates of recurrences, both symptomatic and asymptotic. Thus the measure of therapy success rates not only based on symptom perception remains a goal to be reached., Aims of the Study: This study investigates the role of an implantable loop recorder (ILR) as an additional tool to identify initiating and perpetuating mechanisms of AF. The role of right atrial linear ablation (RALA) procedures is also investigated using the monitoring capabilities of the ILR., Methods and Results: Nine patients (mean age 63.8 +/- 5.9) with paroxysmal AF were referred to our institution as candidates for AF ablation. All patients (pts) had in their medical history several years of AF episodes. Therefore pts were aware of AF related symptoms. Six of them were implanted with an ILR before ablation and were monitored one month before and six months after the procedure. The ILRs stored 54 patient activated events (PAE) and 124 automatically activated events (AAE). 68% of PAEs and 67% of AAEs were classified as appropriate. Most common reasons for inappropriate detections were premature atrial or ventricular contractions among PAEs and undersensing among AAEs. The arrhythmia onset was properly identified in 4 pts (44%). The average AF recurrence rate was 10.8 +/- 3.5 ep/month before ablation and 5.0 +/- 1.8 ep/month after the procedure ( p = 0.042)., Conclusion: The ILR may be a helpful tool in monitoring pts undergoing ablation. Dedicated AF detection characteristics could give additional value to the device. RALA appears as a feasible, safe and relatively effective first approach in AF therapy.

Objectives: The aims of this study were to compare the efficacy of a 2- versus a 3 RF lesions ablation procedure in the RA in patients with paroxysmal AF, and to map right atrial activation during AF., Background: RF catheter-mediated ablation lines mimicking the Maze operation have been proposed as a novel curative approach for AF. The relationship between this type of ablation and right atrial mapping has not been extensively studied., Methods: Twenty-four patients with recurrent, drug-refractory, paroxysmal AF underwent an extensive mapping of the RA before attempting linear lesion RF ablation. Patients were divided into two groups: 15 patients received two linear lesions (Group 1), 9 patients three linear lesions (Group 2)., Results: One-month success rate AF did not recur in 40% of Group 1 patients (6/15) and in 66% (6/9) of Group 2 patients. 27% of patients in Group 1 and 11% of patients in Group 2 had recurrences controlled by drugs. No benefit in 33% of Group 1 patients and 22% of Group 2. Long-term follow-up In the absence of any drug treatment, no AF recurrences were observed in 26% of Group 1 patients (FU: 23 to 47 months) and 55% of Group 2 (FU: 14 to 23 months). No complications were reported., Conclusions: Right atrial linear ablation is safe and may be proposed for AF treatment in selected patients.