Shorter RSPV cryoapplications result in less phrenic nerve injury and similar 1-year freedom from atrial fibrillation.

BACKGROUND: In the 123-study, we prospectively assessed, in a randomized fashion, the minimal cryoballoon application time necessary to achieve pulmonary vein (PV) isolation (PVI) in patients with paroxysmal atrial fibrillation (AF) with the aim to reduce complications by shortening the application duration. The first results of this study demonstrated that shortened cryoballoon applications (<2 minutes) resulted in less phrenic nerve injury (PNI) without compromising acute isolation efficacy for the right PVs. We now report the 1-year follow-up results regarding safety and efficacy of shorter cryoballoon applications. METHODS: A total of 222 patients with AF were randomized to two applications of 1 min "short," 2 min "medium," or 3 min "long" duration, 74 per group. Recurrence of AF and PV reconduction at 1-year follow-up were assessed. RESULTS: The overall 1-year freedom from AF was 79% and did not differ significantly between the short, medium, and long application groups (77%, 74%, and 85% for short, medium, and long application groups, respectively; P = 0.07). In 30 patients, a redo PVI procedure was performed. For all four PVs, there was no significant difference in reconduction between the three groups. Reconduction was most common in the left superior PV (57%). The right superior PV (RSPV) showed significantly less reconduction (17%) compared to the other PVs. CONCLUSIONS: Shortening cryoballoon applications of the RSPV to <2 minutes results in less PNI, while acute success and 1-year freedom from AF are not compromised. Therefore, shorter cryoballoon applications (especially) in the RSPV could be used to reduce PNI.

Comparison of a 6.5, 10, and 15 mm cryoablation catheter-tip for the treatment of common atrial flutter.

AIM: Only a few studies have investigated the effect of large tip sizes for catheter-based cryoablation (cryo). This study evaluates the safety and efficacy of cryo of the cavotricuspid isthmus (CTI) using three cryocatheter-tip sizes. METHODS AND RESULTS: Forty-five consecutive patients with common atrial flutter (AFL) underwent cryo of the CTI using a 6.5, a 10, or a novel 15 mm catheter-tip. Single applications of 3 min were delivered at each site along the CTI. Baseline characteristics of the three groups were comparable. The overall acute success rate was 89% and there was no difference with respect to the tip electrode size (P > 0.05). Fewer applications were required for a 10 mm (6 ± 2, range 3-7) and a 15 mm (6 ± 1, range 4-8) compared with a 6.5 mm catheter-tip (8 ± 3, range 4-14; P < 0.05). Procedure time was significantly shorter with the largest tip electrode (89 ± 26 min vs. 132 ± 28 min (6.5 mm tip), P < 0.05). No complications occurred. After a mean follow-up of 51 ± 5 months, 43 patients (96%) were without recurrence of AFL. CONCLUSIONS: A large (10 or 15 mm) cryoablation catheter-tip requires significantly fewer applications to create bidirectional CTI block compared with a 6.5 mm tip. A significant decrease in procedure time with preservation of the overall safety and efficacy supports the preference of a 15 over a 6.5 mm catheter-tip for cryoablation of AFL.

Catheter-based cryoablation of postinfarction and idiopathic ventricular tachycardia: initial experience in a selected population.

INTRODUCTION: Transvenous cryoablation has proven to be safe and effective for the treatment of supraventricular arrhythmias. The aim of this prospective study was to report the feasibility and safety of catheter-based cryoablation for the treatment of postinfarction and idiopathic ventricular tachycardia (VT). METHODS AND RESULTS: Catheter-based cryoablation was performed in 17 patients (15 men, 58 +/- 18 years). VT occurred after a prior myocardial infarction in 10 and was idiopathic in 7 patients. Cryoablation was performed with a 10-F, 6.5-mm tipped catheter. The ablation site was selected using entrainment mapping techniques for postinfarction VT. The site of the earliest activation time with optimal pace mapping was used for ablation of idiopathic VT. All targeted VTs (12 postinfarction and 7 idiopathic) were acute successfully ablated after a median number of 2 applications of 5 minutes with an average temperature of -82 +/- 4 degrees C. Mean procedure and fluoroscopy times were 204 +/- 52 and 52 +/- 20 minutes for postinfarction VT and 203 +/- 24 and 38 +/- 15 minutes for idiopathic VT. No cryocatheter or cryoenergy complications were observed. After a follow-up of 6 months, 4 of the 10 patients with postinfarction VT had a recurrence. In 1 of the 7 patients with idiopathic VT the index arrhythmia recurred. CONCLUSION: In this small patient population, catheter-based cryoablation of VT was safe and effective. Future studies are needed to evaluate the effect of cryothermy in a larger group of patients, especially those with postinfarction VT.

Typical atrial flutter can effectively be treated using single one-minute cryoapplications: results from a repeat electrophysiological study.

PURPOSE: Catheter-based cryoablation (cryo) has proven to be as effective as radiofrequency energy (RF) ablation for the treatment of arrhythmias. Nevertheless, the duration of cryoapplications has been reported as being significantly longer than RF applications. METHODS: Thirty-seven consecutive patients (28 men; mean age 59 +/- 14 years) with typical atrial flutter (AFL) underwent cryo of the cavotricuspid isthmus (CTI). Applications of 1 min were delivered with a 10-French, 10-mm tipped catheter (CryoCor). If bidirectional CTI block was not obtained after 12 1-min applications, applications of 3 min were selectively delivered to areas of conduction breakthrough. The endpoint of the procedure was creation of bidirectional CTI block and non-inducibility of AFL. RESULTS: A median of 7 (range 3 to 12) 1-min applications were given along the CTI with a mean temperature of -88.6 +/- 2.3 degrees C. Mean fluoroscopy and procedure time were 27 +/- 14 min and 110 +/- 28 min respectively. Five patients required additional 3-min applications; in one patient an overextended ablation catheter prevented the completion of the index-procedure. The acute success rate of the index-procedure was 97%. In 12/24 patients, two with AFL recurrence, resumption of CTI conduction was found 4 months post-ablation. In all patients bidirectional CTI block was re-obtained after a median of one 1-min application. No additional AFL recurrences occurred, after a mean follow-up of 37 +/- 3 (range 30 to 44) months. CONCLUSIONS: Cryo of AFL can successfully be performed using the same application duration as used for RF ablation. Both acute and long-term results are comparable to RF ablation. AFL recurrences occurred in only a minority of patients with resumption of CTI conduction.

Long-term follow-up after cryothermic ostial pulmonary vein isolation in paroxysmal atrial fibrillation.

OBJECTIVES: This study was designed to evaluate the long-term effect of segmental pulmonary vein (PV) cryoablation in patients with recent-onset paroxysmal atrial fibrillation (PAF). BACKGROUND: Patients with PAF have more triggers to initiate and less substrate to sustain atrial fibrillation (AF). Elimination of the potential initiators alone may be sufficient to abolish the arrhythmia. METHODS: Patients with PAF were prospectively recruited from July 2001 to July 2005. If the triggers for AF were identified, PV cryoisolation of the arrhythmogenic vein(s) was performed. Otherwise, all PVs were isolated. RESULTS: Seventy patients with minimal or no heart disease (54 men; age 40 +/- 10 years) were enrolled. The duration of AF was 4 +/- 1 year. The left ventricular ejection fraction and left atrial size were 59 +/- 8% and 41 +/- 5 mm, respectively. An arrhythmogenic PV was found in 10 patients (14%). Complications occurred in 3 patients (4%). No PV stenosis or esophageal injury was detected during a mean follow-up of 33 +/- 15 months. Thirty-four patients (49%) achieved complete success (no AF and no antiarrhythmic drugs [AAD]); 15 patients (22%) had no recurrences with AAD; and 8 patients (11%), still with sporadic bursts of AF, improved >50% with AAD. Overall, 82% of the patients benefited from the procedure. Patients in whom the arrhythmogenic PV was identified and isolated had no recurrences. CONCLUSIONS: Pulmonary vein cryoisolation is effective in 82% of patients with recent-onset PAF during a mean follow-up of 33 +/- 15 (range 15 to 60) months. If the arrhythmogenic PV is identified and isolated, the long-term outcome is excellent, indicating no need to isolate all PVs.

Catheter-based cryoablation permanently cures patients with common atrial flutter.

BACKGROUND: Cryoablation (cryo) has a high success rate in the short-term treatment of atrial flutter (AFL), but evidence of long-term efficacy is lacking. The present study reports the long-term effect of cryo of the cavotricuspid isthmus (CTI) in patients with common AFL. METHODS AND RESULTS: Thirty-five consecutive patients (28 men; mean age, 53 years) underwent cryo of the CTI. In 34 patients, the AFL had a counterclockwise rotation (cycle length, 242+/-43 ms). Eleven patients had structural heart disease. Cryo was performed with a 10F catheter with a 6-mm-tip electrode (CryoCor). Applications (3 to 5 minutes each) were delivered by use of a point-by-point technique to create the ablation line. The acute end point of the procedure was creation of bidirectional isthmus conduction block and noninducibility of AFL. A median of 14 applications (range, 4 to 30) at 10 sites (range, 4 to 19) was given along the CTI with a mean temperature of -80.0+/-5.0 degrees C. Mean fluoroscopy and procedure times were 40+/-26 minutes and 3.2+/-1.3 hours, respectively. Of the 35 patients, 34 were acutely successfully ablated (97%). After a mean follow-up of 17.6+/-6.2 months (range, 9.6 to 26.1 months), 31 patients (89%) did not have recurrence of AFL. Three of the 4 patients with recurrence had a second successful procedure. One patient had transient ST elevation in the inferior leads during cryoapplication. CONCLUSIONS: Cryo produces permanent bidirectional isthmus conduction block of the CTI. Short- and long-term success rates are comparable to those for radiofrequency ablation.

Single cryothermia applications of less than five minutes produce permanent cavotricuspid isthmus block in humans.

OBJECTIVES: The aim of this study was to compare single-3-minute (single-3) with double-3-minute (double-3) cryothermia applications for treatment of atrial flutter (AFL). BACKGROUND: Previous animal studies have indicated the need for a double 5-minute cryothermal application to create large and permanent lesions. METHODS: Forty patients (56 +/- 13 years old) with typical AFL (cycle length 229 +/- 35 ms) were randomized to single-3 (n = 20) or double-3 (n = 20) cryothermia applications at each site along the cavotricuspid isthmus (CTI). Cryoablation was performed with the CryoCor cryoablation system. A successful procedure was defined as noninducibility of AFL with the concomitant presence of bidirectional CTI conduction block under isoproterenol infusion. RESULTS: All but 1 patient (95%) of the single-3 group and all patients (100%) of the double-3 group were successfully ablated. The number of sites needed to create isthmus conduction block was 9 +/- 4 (single-3) and 8 +/- 2 (double-3) (NS). Fluoroscopy time did not differ between the two groups (single-3: 31 +/- 14; double-3: 36 +/- 17 min, NS). The procedure time of the single-3 group was significantly shorter compared to the procedure time of the double-3 group (mean procedure duration 132 +/- 64 vs 159 +/- 50 min, P < .04). After a mean follow-up of 11.7 +/- 4.7 months, two recurrences of AFL occurred in the double-3 group. CONCLUSIONS: Single cryothermia applications of 3 minutes produce permanent CTI conduction block in patients with typical AFL and significantly reduce procedure duration.