[Isthmus-dependent right atrial flutter : Clinical course after isthmus ablation]

Ablation of the cavotricuspid isthmus (CTI) to create bidirectional isthmus blockade is the most effective way to achieve rhythm control in typical atrial flutter. Compared with drug therapy, ablation reduces cardiovascular mortality, all-cause mortality, stroke risk, and the risk of cardiac decompensation. Concomitant arrhythmia of atrial flutter is atrial fibrillation (AF); therefore the duration of oral anticoagulation should be adapted according to the risk of stroke and bleeding. A combined procedure of CTI ablation and pulmonary vein isolation (PVI) in patients with typical atrial flutter but without evidence of AF should be evaluated individually especially in patients aged > 54 years depending on (cardiac) comorbidities. The comprehensive diagnostic view should keep in mind not only arrhythmias but also possibly underlying coronary artery disease.

Long-term results of two-stage ablation approach in coexistent atrial fibrillation and typical atrial flutter: prospective randomized study

Background One of the most arrhythmias associated with atrial fibrillation (AF) is typical atrial flutter (AFL). The main methods of surgical treatment of these arrhythmias is catheter ablation. The problem of catheter ablation strategy for these coexistentarrhythmias is not solved. Purpose: To assess the effectiveness of long-term maintenance of sinus rhythm in a two-stage approach to the interventional treatment of atrial fibrillation associated with typical atrial flutter. Methods: The study included 34 patients aged 41-82 years with AF and coexistent typical AFL. Female 11 (32,35%), male 23 (67,35%). Randomization 1:1. Group 1 (n=17) has been performed radiofrequency ablation (RFA) of the cavotricuspid isthmus (CTI) with radiofrequency catheter isolation of the PV. Group 2 (n=17) has been performed only RFA of CTI. AF and AFL recurrences rate has been evaluated in both groups. Follow-up period 12 months. Results: Procedure duration and fluoroscopy time were less in group 2 that those in group 1. Extended intervention in group 1 was accompanied with complications in two cases. There were no significant differences in AF recurrence rate in both groups (p=0,43183). AFL recurrences has not been found in both groups. Conclusion: One stage ablation approach in AF patients with coexistent AFLassociated with increaseprocedure duration and fluoroscopy time. The frequency of AF recurrence in patients who underwent extended intervention (catheter isolation of the PV and RFA CTI) and in patients who underwent only the elimination of typical atrial flutter, was not statistically significantly different (p = 0.43183). In the presence of AF and typical atrial flutter, a two-stage approach to interventional treatment should be regarded as appropriate.

Impact of cavotricuspid isthmus ablation for typical atrial flutter and heart failure in the elderly-results of a retrospective multi-center study

Introduction

While in the CASTLE-AF trial, in patients with atrial fibrillation and heart failure with reduced ejection fraction, interventional therapy using pulmonary vein isolation was associated with outcome improvement, data on cavotricuspid isthmus ablation (CTIA) in atrial flutter (AFL) in the elderly is rare.

Methods

We included 96 patients between 60 and 85 years with typical AFL and heart failure with reduced or mildly reduced ejection fraction (HFrEF/HFmrEF) treated in two medical centers. 48 patients underwent an electrophysiological study with CTIA, whereas 48 patients received rate or rhythm control and guideline-compliant heart failure therapy. Patients were followed up for 2 years, with emphasis on left ventricular ejection fraction (LVEF) over time. Primary endpoints were cardiovascular mortality and hospitalization for cardiac causes.

Results

Patients with CTIA showed a significant increase in LVEF after 1 (p < 0.001) and 2 years (p < 0.001) in contrast to baseline LVEF. Improvement of LVEF in the CTIA group was associated with significantly lower 2-year mortality (p = 0.003). In the multivariate regression analysis, CTIA remained the relevant factor associated with LVEF improvement (HR: 2.845 CI:95% 1.044-7.755; p = 0.041). Elderly patients (≥ 70 years) further benefited from CTIA, since they showed a significantly reduced rehospitalization (p = 0.042) and mortality rate after 2 years (p = 0.013).

Conclusions

CTIA in patients with typical AFL and HFrEF/HFmrEF was associated with significant improvement of LVEF and reduced mortality rates after 2 years. Patient age should not be a primary exclusion criterion for CTIA, since patients ≥70 years also seem to benefit from intervention in terms of mortality and hospitalization.

Cryoablation as standard treatment of atrial flutter: a prospective, 2-center study (CASTAF)

BACKGROUND

Cryoablation (CRYO) of cavotricuspid isthmus (CTI)-dependent atrial flutter (AFL) has been shown to be non-inferior to radiofrequency ablation (RF) in terms of ablation success and is associated with less pain. However, procedural time has been significantly longer with CRYO compared to RF. A possible explanation for this could be that operators had less experience with CRYO than with RF. The purpose of this study was to test the hypothesis that in the hands of experienced operators, cryoablation of CTI-dependent AFL is effective with procedure-time similar to what is reported for RF.

METHODS

This prospective 2-center study included 184 patients with CTI-dependent AFL - median age 66 years (range 28-83), 159 men (86%). Cryoablation was performed using a 9 F, 8 mm tip catheter (Freezor MAX, Medtronic, Inc, MN, USA). Ablation endpoint was bidirectional CTI-block. Pain was evaluated with a visual analogue scale (VAS 0-10). All operators had experience of at least 25 previous CTI-ablations with CRYO.

RESULTS

The acute success rate was 89%. Procedural time including an observation period of 30 min, was 115 ± 36 min which is similar to procedural times for RF in previous studies. Fluoroscopy time was 11 ± 9 min. Cryoablation was perceived as almost pain- free by the patients, VAS (mean) 1.8 ± 1.2. Success rate at 12-month follow-up (FU) was 88% in patients with primary success. No major adverse events occurred.

CONCLUSIONS

Cryoablation of CTI-dependent AFL is effective, with a low level of procedure-related pain. In experienced hands, the procedure time in this prospective non-randomised trial seems to be in the level of reported procedure times for RF. The long-term relapse rate appears to be higher than for RF.

Cryoballoon ablation for treatment of patients with refractory esophageal neoplasia after first line endoscopic eradication therapy

Background and study aims  Cryoablation with the Cryoballoon device is a novel ablative therapy that uses cycles of freezing and thawing to induce cell death. This single-center prospective study evaluated the feasibility of the focal cryoablation device for the treatment of areas of refractory esophageal neoplasia in patients who had undergone first line endoscopic eradication therapy (EET). Complete remission of dysplasia (CR-D) and complete remission of intestinal metaplasia (CR-IM) at first follow-up endoscopy, durability of disease reversal, rates of stenosis and adverse events were studied. Patients and methods  Eighteen cases were treated. At baseline, nine patients had low-grade dysplasia (LGD), six had high-grade dysplasia (HGD) and three had intramucosal carcinoma (IMC). Median length of dysplastic Barrett's esophagus (BE) treated was 3 cm. The median number of ablations per patient was 11. Each selected area of visible dysplasia received 10 seconds of ablation. One session of cryoablation was performed per patient. Biopsies were performed at around 3 months post-ablation. Results  CR-D was achieved in 78 % and CR-IM in 39 % of patients. There were no device malfunction or adverse events. Stenosis was noted in 11 % of cases. At a median follow up of 19-months, CR-D was maintained in 72 % of patients and CR-IM in 33 %. Conclusions  Cryoablation appears to be a viable rescue strategy in patients with refractory neoplasia. It is well tolerated and successful in obtaining CR-D and CR-IM in patients with treatment-refractory BE. Further trials of dosimetry, efficacy and safety in treatment-naïve patients are underway.

Biophysical properties, efficacy, and lesion characteristics of a new linear cryoablation catheter in a canine model

BACKGROUND

The cryoballoon (CB) catheter is an established tool for pulmonary vein isolation (PVI), but its use is limited for that purpose.

OBJECTIVE

The purpose of this study was to investigate the biophysical properties of a newly developed linear cryoablation catheter for creation of linear ablation lesions in an in vivo model.

METHODS

Twenty-nine dogs (14 acutely ablated, 15 chronically followed) underwent cryoablation using the linear cryoablation catheter. Regions of interest included the cavotricuspid isthmus (CTI), mitral isthmus (MI), left atrial (LA) roof, and LA posterior wall in an acute study. Cryoablations for CTI and MI were performed in 14 atrial fibrillation animals after PVI and followed over 1 month in the chronic study. Tissue temperature during cryoablation was monitored using implanted thermocouples in the regions of interest. Gross and microscopic pathologic characteristics of the lesions were assessed.

RESULTS

In acute animals, lesion length (transmurality) was CTI 34 ± 4 mm (89% ± 11%); MI 29 ± 4 mm (90% ± 13%); LA roof 19 ± 3 mm (90% ± 8%); and LA posterior wall 19 ± 2 mm (81% ± 13%), with 1 or 2 freezes. Chronic bidirectional block was achieved in 13 of 14 CTI (93%) and 10 of 14 MI (71%) ablations after 1-month follow-up and was consistent with lesion continuity and transmurality upon pathology. The lowest tissue temperature correlated well with the closest distance to the linear cryocatheter (r = 0.688; P <.001).

CONCLUSION

This linear cryocatheter created continuous and transmural linear lesions with "single-shot" cryoenergy application and has the potential for clinical use in the setting of various arrhythmias.

Evaluation of myocardial injury induced by different ablation approaches (radiofrequency ablation versus cryoablation) in atrial flutter patients: a meta-analysis

Background: To evaluate myocardial injury in Atrial flutter (AFL) patients undergoing Radiofrequency ablation (RF) and cryoablation (CRYO) treatments.

Methods: We conducted a systematic search on PubMed, Embase, Cochrane Library, and CBM databases. All relevant clinical trials (up to October 2018) on myocardial injury in AFL patients were retrieved and subsequent results analyzed with a random-effects model or a fixed-effects model.

Results: A total of eight clinical trials with a sample size of 644 patients, were identified and incorporated in the present study. The results indicated no significant differences in creatine kinase (CK) levels (mean difference (MD) = 62.74, P=0.46; 4–6 h and MD = 30.73, P=0.49; 12–24 h after ablation), creatine kinase MB(CK-MB) levels (MD = 17.32, P=0.25; 12–24 h post-ablation), troponinI (TnI) levels (MD = 0.12, P=0.08; 6 h after ablation), and troponin T (TnT) levels (MD = 0.30, P=0.08; 4–6 h post-ablation) between the two treatment approaches. However, patients receiving CRYO xhibited higher levels of CK (MD = 179.54, P=0.04; tested immediately after the procedure), CK-MB (MD = 10.08, P=0.004) 4–6 h after ablation, and TnT (MD = 0.19, P=0.002) tested the next morning. Moreover, those patients had a significantly reduced pain perception (odds ratio (OR) = 0.05, P=0.04) compared with those in the RF group.

Conclusion: These results indicate that CRYO in comparison with RF significantly increases myocardial injury in AFL patients. Additionally, it decreases pain perception during the procedure. Further large-sampled studies are needed to support these findings.

Atrial Tachyarrhythmias and Atrial Flutter: the Basics of Diagnostics and Modern Opportunities of Therapy

The article is devoted to the description of all types of atrial tachyarrhythmias, including inappropriate sinus tachycardia, which, as a rule, is not paid enough attention in the domestic literature, sinoatrial node reentrant tachycardia, focal and multifocal atrial tachycardia, atrial flutter, and atrial fibrillation. The electrophysiological mechanisms of development and electrocardiographic criteria for the diagnosis of these cardiac rhythm disturbances are presented. Along with this, the article discusses the modern view of the strategy and tactics of pharmacological cardioversion and preventive therapy in patients with the main types of atrial tachyarrhythmias and atrial flutter. It is noted that the prognosis for inappropriate sinus tachycardia, as a rule, is favorable, and therefore, aim of treatment is to reduce the symptoms, and in their absence medical treatment is not necessary. Much attention is paid to drug and interventional treatment of atrial flutter. It is emphasized that catheter ablation of isthmus-dependent atrial flutter in most cases is preferred over long-term pharmacotherapy. However, in prolonged observation (more than 3 years), nearly 1/3 of patients may develop paroxysmal atrial fibrillation. At the same time, catheter ablation of atypical atrial flutter is, in most cases, substantially less effective. The indications and side effects of catheter ablation of the sinus node are also discussed. The authors provide a critical analysis of traditional approaches to the treatment of atrial tachyarrhythmias and analyze new recommendations for the management of these patients presented in Europe and the USA. Based on these recommendations, clear algorithms for the management of patients with atrial tachyarrhythmias are given. The need to prevent thromboembolic complications in some types of atrial tachyarrhythmias is emphasized.

Focal cryoballoon versus radiofrequency ablation of dysplastic Barrett's esophagus: impact on treatment response and postprocedural pain

BACKGROUND AND AIMS

Radiofrequency ablation (RFA) is safe and effective for eradicating Barrett's esophagus (BE) but is associated with significant postprocedural pain. Alternatively, balloon-based focal cryoablation (CRYO) has recently been developed, which preserves the extracellular matrix and might therefore be less painful. Although data for CRYO are still limited, uncontrolled studies suggest comparable safety and efficacy to RFA in eradicating limited BE areas. Therefore, secondary endpoints such as pain might become decisive for treatment selection. We aimed to compare efficacy and tolerability between focal CRYO and RFA.

METHODS

We identified BE patients undergoing focal ablation (either RFA or CRYO) of all visible BE from our prospective cohort in 2 Dutch referral centers. After ablation, patients completed a 14-day digital diary to assess chest pain (0-10), dysphagia (0-4), and analgesics use. A follow-up endoscopy was scheduled after 3 months to assess the BE surface regression (blindly scored by 2 independent BE expert endoscopists). Outcomes were BE surface regression; 14-day cumulative scores (area under the curves [AUCs]) for pain, dysphagia, analgesics, and peak pain.

RESULTS

We identified 46 patients (20 CRYO, 26 RFA) with similar baseline characteristics. The BE regression was comparable (88% vs 90%, P = .62). AUCs for pain, dysphagia, and analgesics were significantly smaller after CRYO versus RFA (all P < .01). Peak pain was lower after CRYO (visual analog scale 2 vs 4, P < .01), and the duration of pain was also shorter after CRYO (2 vs 4 days, P < .01). CRYO patients used analgesics for 2 days versus 4 days for RFA (P < .01).

CONCLUSIONS

In this multicenter, nonrandomized cohort study, we found no differences in efficacy after a single treatment with CRYO and RFA for short-segment BE. Patients reported less pain after CRYO as compared with RFA. Moreover, CRYO patients used fewer analgesics. Our results suggest a different pain course favoring CRYO over RFA, but a randomized trial is needed for definitive conclusions. (Clinical trial registration number: NCT02249975.).

Creating bidirectional conduction block in the cavotricuspid isthmus by cryothermal ablation with a short freeze time: Insight from the results with a 2-minute freeze cycle

BACKGROUND

Optimal freeze doses are unknown during cryothermal cavo-tricuspid isthmus (CTI) ablation. This study aimed to evaluate the feasibility of 2-minute freeze doses for CTI ablation.

METHODS

Forty-eight consecutive patients undergoing cryothermal CTI ablation following pulmonary vein isolation were enrolled. CTI ablation was performed with 2-minute freeze cycles and 8-mm tip cryocatheters.

RESULTS

Bidirectional CTI block was successfully achieved in 45(93.8%) patients with a median of 5.0[4.0-6.0] cryocatheter applications. The total procedure and fluoroscopic times were a median of 16.5[13.0-20.0] and 4.0[2.0-5.0]min, respectively. A crossover to radiofrequency was performed in 3 patients including 1 due to coronary spasms during the cryoapplication. The tip temperature when block was achieved was a median of -81.0[-73.3 - -84.0]°C. Application times from the start of the last application to achieving block were significantly longer in patients with acute conduction resumption than in those without (46.8±4.0 vs. 20.2±8.8s, p<0.0001), and the optimal cutoff point for predicting no acute resumption was 38.5s (sensitivity 100%, specificity 99.5%). Vasospastic angina occurred in 2 patients, during the procedure in 1 and after in another. Durability could be evaluated a median of 6.0[3.0-8.0] months after the procedure in 14 patients, and conduction resumption was observed in 8(57.1%). The majority of gaps were located at the inferior vena cava edge.

CONCLUSIONS

Acute CTI block was obtained by 2-minute freeze cycles with short procedure and fluoroscopic times. Care should be taken to avoid coronary spasms during the peri-procedural period. Additional cryoapplications might be required to improve conduction block durability.

Myocardial injury during radiofrequency and cryoablation of typical atrial flutter

PURPOSE

Cardiac enzyme elevation after radiofrequency (RF) catheter ablation of atrial flutter (AFL) is common. Some studies found that cryoablation (CRYO) of AFL, compared to RF, is associated with higher levels of troponin, a finding that may indicate CRYO causes a greater amount of myocardial injury than RF. However, other investigations found no significant differences between troponin levels after CRYO versus RF. We have in a randomized study compared the post-procedural troponin I levels in RF and CRYO and the possible relation to procedural outcome and complications.

METHODS

We randomized 153 patients with cavotricuspid isthmus (CTI)-dependent AFL to CRYO or RF (78 CRYO; 75 RF). RF was performed with a 3.5-mm open-irrigated-tip catheter, and CRYO was performed with an 8-mm-tip catheter. Troponin I levels were measured before and 6 h after ablation.

RESULTS

Acute procedural success was achieved in 71/75 patients in the RF and in 72/78 patients in the CRYO. Troponin I levels were significantly elevated in both groups (baseline 0.012, 6th hour 0.35 ng/ml; p < 0.001). Troponin I levels were similar for RF and CRYO. Troponin I levels were higher in patients with acute failure compared to patients with acute success (0.48 ± 0.4 and 0.34 ± 0.16 ng/ml, p = 0.029); however, there was no difference between patients with or without late recurrence. There were no major complications in any group.

CONCLUSION

RF and CRYO for CTI-dependent AFL resulted in similar amounts of procedural myocardial injury. Troponin I levels had no prognostic value for late recurrence of AFL and there were no complications related to high troponin I levels.

Efficacy comparison between cryoablation and radiofrequency ablation for patients with cavotricuspid valve isthmus dependent atrial flutter: a meta-analysis

We perform this meta-analysis to compare the efficacy and safety of cryoablation versus radiofrequency ablation for patients with cavotricuspid valve isthmus dependent atrial flutter. By searching EMBASE, MEDLINE, PubMed and Cochrane electronic databases from March 1986 to September 2014, 7 randomized clinical trials were included. Acute (risk ratio[RR]: 0.93; P = 0.14) and long-term (RR: 0.94; P = 0.08) success rate were slightly lower in cryoablation group than in radiofrequency ablation group, but the difference was not statistically significant. Additionally, the fluoroscopy time was nonsignificantly reduced (weighted mean difference[WMD]: −2.83; P = 0.29), whereas procedure time was significantly longer (WMD: 25.95; P = 0.01) in cryoablation group compared with radiofrequency ablation group. Furthermore, Pain perception during the catheter ablation was substantially less in cryoabaltion group than in radiofrequency ablation group (standardized mean difference[SMD]: −2.36; P < 0.00001). Thus, our meta-analysis demonstrated that cryoablation and radiofrequency ablation produce comparable acute and long-term success rate for patients with cavotricuspid valve isthmus dependent atrial flutter. Meanwhile, cryoablation ablation tends to reduce the fluoroscopy time and significantly reduce pain perception in cost of significantly prolonged procedure time.

Open-irrigated laser catheter ablation produces flow-dependent sizes of lesions

BACKGROUND

Growth and sizes of lesions produced during catheter ablation is difficult to control. Laser lesion formation was evaluated during various flow rates and energy settings by using an open-irrigated laser catheter on a thigh-muscle dog model.

METHODS

Laser radiation at 15 W or 20 W was applied in blood for 10 seconds, 20 seconds, 30 seconds, 40 seconds, and 50 seconds during an irrigation flow of 16 mL/min or 35 mL/min, in direct contact, and in a noncontact mode of laser application. Lesions were evaluated morphometrically.

RESULTS

There was a linear increase of lesions with the increase of the level of energy applied. Maximal depth of lesions achieved during a flow rate of 16 mL/min at 15 W/50 seconds increased significantly from 9.9 ± 0.3 mm to 12.1 ± 0.5 mm, and at 20 W/50 seconds from 11.1 ± 0.55 mm to 12.4 ± 0.26 mm, when irrigation flow was 35 mL/min (P < 0.5). However, difference of lesion increase between 15 W and 20 W was not significant (P = 0.30). Lesions were achieved also in a noncontact mode of radiation at a distance of 1-2 mm, but not at 5 mm away. Radiation at 20 W > 40 seconds and a flow rate of 35 mL/min may cause steam pop with intramural cavitation.

CONCLUSIONS

By using an open-irrigated laser catheter augmentation of catheter flow increases lesion sizes. Lesions can be achieved also in a noncontact mode of radiation. In order to avoid unwanted effects the level of energy applied must be limited.