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Catheter Ablation of Atrial Fibrillation and Atrial Flutter: A Comparison of Cryo and Radiofrequency Techniques
Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences, Cardiology-Arrhythmia.
2014 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Atrial fibrillation (AF) and atrial flutter (AFl) are two of the most common arrhythmias encountered in the population. Catheter ablation has emerged as a useful tool in the treatment of these arrhythmias. Although radiofrequency (RF) is the most commonly used energy source for ablation, cryoenergy may have some advantageous properties. The purpose of these studies was to evaluate and compare ablation with novel ablation catheters using either of these energy sources.

When used for AFl ablation, cryoenergy was associated with less perceived pain than radiofrequency. However, the acute success rate was significantly lower for cryoablation (56%) compared with RF ablation (100%) in our study.

Being one of the first centres to use a new so-called “one-shot” device for pulmonary vein isolation (PVI), the cryoballoon, we described our initial experience with this catheter in 40 patients undergoing AF ablation.  A high rate of PVI could be achieved although an additional cryocatheter was needed in 44% of the procedures. Freedom from arrhythmia-related symptoms was seen in 53% after a mean follow-up of 8.9 months.

Comparing the cryoballoon and a RF-based device intended for PVI, the pulmonary vein ablation catheter (PVAC), both catheters proved comparably effective (≥93%) and safe in achieving PVI with comparable procedure times. After 12 months only 46% versus 34% (ns) in the cryoballoon- and the PVAC group, respectively, were regarded as free from AF without antiarrhythmic drugs, after one ablation procedure, whereas 60% versus 54% reported clinical success. Quality of life was significantly increased in both groups, to a level comparable with the general Swedish population.

We tested the hypothesis that RF ablation would be accompanied by a higher activation of the coagulation and inflammatory systems, measured by biomarkers. Such a difference could not be supported in our study, which showed a comparable response with either technique, even though the cryoballoon caused more pronounced myocardial damage.

Two different energy settings with different ratios of bipolar-to-unipolar energy were tested with the PVAC under the hypothesis that ablation with a higher proportion of unipolar energy would require fewer applications in order to achieve PVI. However, this study failed to show any difference between the groups.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2014. , 90 p.
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Medicine, ISSN 1651-6206 ; 959
National Category
Medical and Health Sciences
Identifiers
URN: urn:nbn:se:uu:diva-212806ISBN: 978-91-554-8830-7 (print)OAI: oai:DiVA.org:uu-212806DiVA: diva2:679637
Public defence
2014-02-14, Enghoff salen, Ing 50, Akademiska sjukhuset, Uppsala, 09:15 (English)
Opponent
Supervisors
Available from: 2014-01-23 Created: 2013-12-14 Last updated: 2014-02-10
List of papers
1. Acute and clinical effects of cryoballoon pulmonary vein isolation in patients with symptomatic paroxysmal and persistent atrial fibrillation
Open this publication in new window or tab >>Acute and clinical effects of cryoballoon pulmonary vein isolation in patients with symptomatic paroxysmal and persistent atrial fibrillation
2008 (English)In: Europace, ISSN 1099-5129, E-ISSN 1532-2092, Vol. 10, no 11, 1277-1280 p.Article in journal (Refereed) Published
Abstract [en]

AIMS: To assess the acute effects, safety, and clinical outcome of atrial fibrillation (AF) ablation using a cryoballoon catheter. METHODS AND RESULTS: Forty patients with paroxysmal or persistent AF underwent pulmonary vein (PV) isolation with a cryoballoon catheter (Arctic Front, CryoCath). Electrocardiograms were recorded in case of symptomatic AF recurrences, and a 24 h Holter recording was performed at last follow-up. Complete PV isolation was achieved in 39 (91%) of the 43 procedures (56% with the cryoballoon catheter alone, 44% with an additional conventional ryocatheter). The number of balloon applications per procedure was 9.6 +/- 1.6. The PV isolation rate was significantly higher (83.9%) if total vessel occlusions were obtained than if intermediate (63.6%, P = 0.01) or poor occlusions were achieved (38.1%, P = 0.0002). The mean procedure time was 239 +/- 48 min. At follow-up (mean 8.9 +/- 4.6 months), 52.5% of patients were free from arrhythmia-related symptoms and another 17.5% had reduction of arrhythmia-related symptoms. Two cases each of phrenic nerve paralysis and dysphagia occurred. CONCLUSIONS: Cryoballoon PV isolation is a feasible technique with a high acute success rate and comparable clinical outcome to radiofrequency ablation. Although complications were rare, the need for an additional conventional cryocatheter warrants further development of the technique.

National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:uu:diva-103443 (URN)10.1093/europace/eun286 (DOI)000260556300006 ()18955410 (PubMedID)
Available from: 2009-05-19 Created: 2009-05-19 Last updated: 2017-12-13Bibliographically approved
2. A prospective randomised comparison of large-tip cryoablation and 8-mm-tip radiofrequency catheter ablation of atrial flutter
Open this publication in new window or tab >>A prospective randomised comparison of large-tip cryoablation and 8-mm-tip radiofrequency catheter ablation of atrial flutter
2009 (English)In: Journal of interventional cardiac electrophysiology (Print), ISSN 1383-875X, E-ISSN 1572-8595, Vol. 24, no 2, 127-31 p.Article in journal (Refereed) Published
Abstract [en]

PURPOSE: Although radiofrequency (RF) energy is routinely used for tricuspid isthmus (TI) ablation, it is often associated with discomfort. The paucity of studies comparing the feasibility and efficacy of cryo- versus RF energy for TI-ablation urged us to conduct a prospective, randomised trial. METHODS: Forty patients with atrial flutter (AFl) were randomised to RF- or cryoenergy for TI-ablation. Perceived pain was scored from 1 to 10 on a Visual Analogue Scale. RESULTS: Significantly lower pain scores were recorded for cryoablation versus RF ablation (0.96 +/- 0.73 versus 4.2 +/- 2.4, p = 0.00004). Cryoablation was associated with significantly longer procedure duration and ablation time (137 +/- 35 versus 111 +/- 29 min, p = 0.016 and 81 +/- 40 versus 48 +/- 30 min, p = 0.007) and lower acute success rate (56% versus 100%, p = 0.001) than RF ablation. The recurrence of AFl was 20% (cryo) versus 15% (RF; p = 0.45) after a mean of 15.1 months follow-up. CONCLUSION: Cryoablation results in significantly less pain and discomfort compared to RF ablation of AFl, which is offset by the significantly lower acute success rate.

National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:uu:diva-103439 (URN)10.1007/s10840-008-9315-1 (DOI)000263145900008 ()18987965 (PubMedID)
Available from: 2009-05-19 Created: 2009-05-19 Last updated: 2017-12-13Bibliographically approved
3. Ablation of atrial fibrillation with cryoballoon or duty-cycled radiofrequency pulmonary vein ablation catheter: a randomized controlled study comparing the clinical outcome and safety; the AF-COR study
Open this publication in new window or tab >>Ablation of atrial fibrillation with cryoballoon or duty-cycled radiofrequency pulmonary vein ablation catheter: a randomized controlled study comparing the clinical outcome and safety; the AF-COR study
2013 (English)In: Europace, ISSN 1099-5129, E-ISSN 1532-2092, Vol. 15, no 11, 1567-1573 p.Article in journal (Refereed) Published
Abstract [en]

AIMS:

The urge to facilitate the atrial fibrillation (AF) ablation procedure has led to the development of new ablation catheters specifically designed as 'one-shot tools' for pulmonary vein isolation (PVI). The purpose of this study was to compare the efficacy, safety, and procedure times for two such catheters using different energy sources.

METHODS AND RESULTS:

One hundred and ten patients, referred for ablation of paroxysmal or persistent AF, were randomized to treatment with either the cryoballoon or the circular multipolar duty-cycled radiofrequency-based pulmonary vein ablation catheter (PVAC). Complete PVI was achieved in 98 vs. 93% patients in the cryoballoon and PVAC group, respectively, with complication rates of 8 vs. 2% (P = 0.2). Complete freedom from AF, without antiarrhythmic drugs, after one single ablation procedure was seen in 46% in the cryoballoon vs. 34% after 12 months (P = 0.2). Procedure times were comparable, but fluoroscopy time was shorter for the cryoballoon (32 ± 16 min) than for the PVAC procedures (47 ± 17 min) (P < 0.001). A significant improvement of quality of life (QoL) and arrhythmia-related symptoms was seen in both groups after ablation.

CONCLUSION:

Both catheters proved comparably effective and safe in achieving acute PVI, apart from the shorter fluoroscopy times achieved with the cryoballoon. At follow-up, there was no statistically significant difference between the groups regarding freedom from AF and clinical success. The QoL increased to the same levels as for the general Swedish population in both groups.

National Category
Medical and Health Sciences
Research subject
Cardiology
Identifiers
urn:nbn:se:uu:diva-201282 (URN)10.1093/europace/eut104 (DOI)000326674600006 ()23703361 (PubMedID)
Available from: 2013-06-10 Created: 2013-06-10 Last updated: 2017-12-06Bibliographically approved
4. Comparison of effects on coagulation and inflammatory markers using a duty-cycled bipolar and unipolar radiofrequency pulmonary vein ablation catheter vs. a cryoballoon catheter for pulmonary vein isolation
Open this publication in new window or tab >>Comparison of effects on coagulation and inflammatory markers using a duty-cycled bipolar and unipolar radiofrequency pulmonary vein ablation catheter vs. a cryoballoon catheter for pulmonary vein isolation
2013 (English)In: Europace, ISSN 1099-5129, E-ISSN 1532-2092, Vol. 15, no 6, 798-804 p.Article in journal (Refereed) Published
Abstract [en]

AIMS:

Thrombo-embolic events are one of the most feared complications related to atrial fibrillation (AF) ablation. Since radiofrequency (RF) energy is thought to be associated with a higher risk of thrombus formation than cryoenergy, the purpose of this study was to assess if the degree of activation of coagulation and inflammatory markers differed between ablation procedures performed with a cryoballoon catheter vs. a RF energy-based pulmonary vein ablation catheter (PVAC), respectively.

METHODS AND RESULTS:

Thirty patients referred for AF ablation were randomized to pulmonary vein isolation with either the cryoballoon or the PVAC. Biomarkers were studied for endothelial damage (von Willebrand factor antigen), platelet activation (soluble P-selectin), and coagulation activity [prothrombin fragment 1 + 2 (F1 + 2) and D-dimer] at five different time points during the procedure. Troponin I (Trop I) and C-reactive protein were analysed to reflect myocardial destruction and inflammatory activity. Markers of endothelial damage and platelet activation increased after ablation in both the cryo and the RF group. Similarly, the D-dimer levels increased significantly (P = 0.001) in both groups, whereas the F1 + 2 levels increased after the transseptal puncture only (P = 0.001). The overall activation of the coagulation system was, however, comparable between the groups. The cryoballoon was associated with higher Trop I compared with the PVAC (P < 0.001), but the ratios between biomarkers and Trop I were higher with the PVAC than with the cryoballoon.

CONCLUSION:

Even though the cryoballoon causes a higher degree of myocardial destruction than the PVAC, markers of coagulation, endothelial damage, and inflammation were comparable between the two techniques.

National Category
Medical and Health Sciences
Research subject
Cardiology
Identifiers
urn:nbn:se:uu:diva-196307 (URN)10.1093/europace/eus411 (DOI)000319468300010 ()23362019 (PubMedID)
Available from: 2013-03-07 Created: 2013-03-07 Last updated: 2017-12-06Bibliographically approved
5. Efficacy and safety of different energy settings for atrial fibrillation ablation using the duty-cycled radiofrequency ablation catheter (PVAC)
Open this publication in new window or tab >>Efficacy and safety of different energy settings for atrial fibrillation ablation using the duty-cycled radiofrequency ablation catheter (PVAC)
2014 (English)In: Journal of cardiovascular medicine and cardiology, Vol. 1, 102- p.Article in journal (Refereed) Published
Abstract [sv]

Catheter based pulmonary vein isolation (PVI), is the recommended therapy for drug-refractory atrial fibrillation (AF) [1]. The procedure may be technically challenging, can be time consuming and highly dependent on operators skill. In order to improve the efficacy of PV isolation, shorten the procedure time and learning curve of operators; new specially designed catheters for pulmonary vein isolation have been developed [2-4]. One of these catheters is the Pulmonary Vein Ablation Catheter (PVAC) (Medtronic; Minneapolis, USA), which is a 10-pole circular, over the wire catheter used in combination with a multi-channel, duty-cycled radiofrequency generator (GENius; Medtronic) [2]. The feasibility of the PVAC has been demonstrated in a number of studies and randomized clinical studies have reported similar clinical results compared to point-by-point ablation around the pulmonary veins [2,5-9]. The energy can be delivered in a unipolar or bipolar setting or combined in various ratios. A higher proportion of unipolar energy will give deeper lesions but less energy between the poles possibly leading to non-continuous lines [12]. Although certain energy settings have been recommended for PV isolation there are no randomized studies that have compared the different settings for this purpose. The aim of this study was therefore to compare the efficacy and safety of PV isolation using a 4:1 versus a 2:1 unipolar/bipolar energy setting with the PVAC. Our hypothesis was that the 2:1 setting, delivering more unipolar energy, would result in deeper and more transmural lesions for pulmonary vein isolation leading to fewer applications and thus shorter procedure times.

National Category
Cardiac and Cardiovascular Systems
Identifiers
urn:nbn:se:uu:diva-212175 (URN)
Available from: 2013-12-13 Created: 2013-12-06 Last updated: 2014-11-13Bibliographically approved

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