Risk assessment in patients with symptomatic and asymptomatic pre-excitation.

AIMS: Controversy remains as to whether the exercise stress test (EST) is sufficient for risk evaluation in patients with pre-excitation. This study aims to clarify the usefulness of EST in risk stratification in both asymptomatic and symptomatic patients presenting with pre-excitation. METHODS AND RESULTS: This prospective study includes consecutive asymptomatic and symptomatic patients with pre-excitation referred for risk assessment. All participants performed an incremental EST (bicycle) prior to an electrophysiology study (EPS). Primary data from the EST included loss of pre-excitation during exercise, and primary data from the EPS included the measurement of accessory pathway effective refractory period (APERP), shortest pre-excited RR interval (SPERRI), and inducible arrhythmia with the use of a beta-adrenergic receptor agonist if deemed necessary. One hundred and sixty-four patients (59 asymptomatic, 105 symptomatic) completed an EST and EPS. Forty-five patients (27%) demonstrated low-risk findings on EST, of which 19 were asymptomatic and 26 were symptomatic. Six patients with low-risk EST findings had SPERRI/APERP ≤ 250 ms at EPS, and two of them were asymptomatic. The sensitivity, specificity, positive predictive value, negative predictive value (NPV), and accuracy of low-risk EST for excluding patients with SPERRI/APERP ≤ 250 ms were 40, 91, 87, 51, and 60%, respectively. The number of patients with inducible arrhythmia at EPS was similar in the asymptomatic (36, 69%) and symptomatic (73, 61%) groups. CONCLUSION: Sudden loss of pre-excitation during EST has a low NPV in excluding high-risk APs. The EPS with the use of isoproterenol should be considered to accurately assess the risk of patients with pre-excitation regardless of symptoms (ClinicalTrials.gov Identifier: NCT03301935).

Association between catheter ablation of atrial fibrillation and mortality or stroke.

OBJECTIVE: Catheter ablation of atrial fibrillation effectively reduces symptomatic burden. However, its long-term effect on mortality and stroke is unclear. We investigated if patients with atrial fibrillation who undergo catheter ablation have lower risk for all-cause mortality or stroke than patients who are managed medically. METHODS: We retrospectively included 5628 consecutive patients who underwent first-time catheter ablation for atrial fibrillation between 2008 and 2018 at three major Swedish electrophysiology units. Control individuals with an atrial fibrillation diagnosis but without previous stroke were selected from the Swedish National Patient Register, resulting in a control group of 48 676 patients. Propensity score matching was performed to produce two cohorts of equal size (n=3955) with similar baseline characteristics. The primary endpoint was a composite of all-cause mortality or stroke. RESULTS: Patients who underwent catheter ablation were healthier (mean CHA2DS2-VASc score 1.4±1.4 vs 1.6±1.5, p<0.001), had a higher median income (288 vs 212 1000 Swedish krona [KSEK]/year, p<0.001) and had more frequently received university education (45.1% vs 28.9%, p<0.001). Mean follow-up was 4.5±2.8 years. After propensity score matching, catheter ablation was associated with lower risk for the combined primary endpoint (HR 0.58, 95% CI 0.48 to 0.69). The result was mainly driven by a decrease in all-cause mortality (HR 0.51, 95% CI 0.41 to 0.63), with stroke reduction showing a trend in favour of catheter ablation (HR 0.75, 95% CI 0.53 to 1.07). CONCLUSIONS: Catheter ablation of atrial fibrillation was associated with a reduction in the primary endpoint of all-cause mortality or stroke. This result was driven by a marked reduction in all-cause mortality.

Comparing efficacy and safety in catheter ablation strategies for atrial fibrillation: a network meta-analysis.

BACKGROUND: There is no consensus on the most efficient catheter ablation (CA) strategy for patients with atrial fibrillation (AF). The objective of this study was to compare the efficacy and safety of different CA strategies for AF ablation through network meta-analysis (NMA). METHODS: A systematic search of PubMed, Web of Science, and CENTRAL was performed up to October 5th, 2020. Randomized controlled trials (RCT) comparing different CA approaches were included. Efficacy was defined as arrhythmia recurrence after CA and safety as any reported complication related to the procedure during a minimum follow-up time of 6 months. RESULTS: In total, 67 RCTs (n = 9871) comparing 19 different CA strategies were included. The risk of recurrence was significantly decreased compared to pulmonary vein isolation (PVI) alone for PVI with renal denervation (RR: 0.60, CI: 0.38-0.94), PVI with ganglia-plexi ablation (RR: 0.62, CI: 0.41-0.94), PVI with additional ablation lines (RR: 0.8, CI: 0.68-0.95) and PVI in combination with bi-atrial modification (RR: 0.32, CI: 0.11-0.88). Strategies including PVI appeared superior to non-PVI strategies such as electrogram-based approaches. No significant differences in safety were observed. CONCLUSIONS: This NMA showed that PVI in combination with additional CA strategies, such as autonomic modulation and additional lines, seem to increase the efficacy of PVI alone. These strategies can be considered in treating patients with AF, since, additionally, no differences in safety were observed. This study provides decision-makers with comprehensive and comparative evidence about the efficacy and safety of different CA strategies. SYSTEMATIC REVIEW REGISTRATION: PROSPERO registry number: CRD42020169494 .

Comparing Efficacy and Safety in Catheter Ablation Strategies for Paroxysmal Atrial Fibrillation: A Network Meta-Analysis of Randomized Controlled Trials.

Although catheter ablation (CA) is an established treatment for paroxysmal atrial fibrillation (PAF), there is no consensus regarding the most efficient CA strategy. The objective of this network meta-analysis (NMA) was to compare the efficacy and safety of different CA strategies for PAF. A systematic search was performed in PubMed, Web of Science, and CENTRAL until the final search date, 5 October 2020. Randomised controlled trials (RCT) comparing different CA strategies and methods for pulmonary vein isolation (PVI) were included. Efficacy was defined as lack of arrhythmia recurrence after CA and safety as any reported complication related to the procedure during a minimum follow-up time of six months. In total, 43 RCTs comparing 11 different CA strategies involving 6701 patients were included. The risk of recurrence was significantly decreased in comparison with PVI with radiofrequency only for the following treatments: PVI with adjuvant ablation (RR: 0.79, CI: 0.65-0.97) and PVI with sympathetic modulation (RR: 0.64, CI: 0.46-0.88). However, PVI with radiofrequency was superior to non-PVI strategies (RR: 1.65, CI: 1.2-2.26). No statistically significant difference was found in safety between different CA strategies. Concerning different PVI strategies, no difference was observed either in efficacy or in safety between tested strategies. This NMA suggests that different PVI strategies are generally similar in terms of efficacy, while PVI with additional ablation or sympathetic modulation may be more effective than PVI alone. This study provides decision-makers with insights into the efficacy and safety of different CA strategies.

Cryoablation of atypical atrioventricular nodal reentry tachycardia.

AIM: Data on ablation for atypical recurrent atrioventricular nodal reentry tachycardia (AVNRT) and long-term follow-up are generally sparse. Furthermore, the rate of recurrence and safety of cryoablation for atypical AVNRT has not been established. We compared patients cryoablated for atypical AVNRT and typical AVNRT during long-term follow-up. METHODS: All patients (n = 2612) who underwent catheter ablation for AVNRT at the Karolinska University Hospital between January 2009 and August 2019 were analyzed. A total of 91 patients undergoing first-time cryoablation for atypical AVNRT were included. A control group with first-time cryoablation for typical AVNRT was matched in a 1:1 ratio. Patients were followed-up for recurrences for a median of 5.0 years (interquartile range: 3.1-7.5 years). RESULTS: After 5 years, AVNRT recurrence occurred in 10 patients (11.0%) in the atypical AVNRT group and in 8 patients (8.8%) in the typical AVNRT group (hazard ratio: 1.31 [95% confidence interval: 0.52-3.32]; p = 0.568). The duration of the index procedure was significantly longer for atypical compared to typical AVNRT ablation (132.1 ± 49.2 min vs. 110.1 ± 38.8 min; p = 0.001). Transient AV blocks occurred in a similar fashion in the atypical compared to typical group (11 [12.1%] vs. 4 [4.9%]; p = 0.103). However, no ablation induced persistent AV block developed in either group. CONCLUSION: Cryoablation for atypical AVNRT showed similar rate of recurrences and safety compared to typical AVNRT during long-term follow-up.

Low incidence of major complications after the first six hours post atrial fibrillation ablation: Is same-day discharge safe and feasible in most patients?

AIMS: This study evaluates the incidence of procedural complications related to catheter ablation of atrial fibrillation (AF) to assess the potential feasibility and safety of same-day discharge in a large cohort. METHODS: We performed an analysis of prospectively collected data of complications of all patients staying overnight after undergoing AF ablation between 2001 and 2020 at a tertiary center. Using medical records, we analyzed complications occurring intraprocedurally until 6 h postablation and between 6 h postablation and discharge the day after the ablation procedure. RESULTS: In 5414 AF ablations, we identified a total of 108 (2.0%) major complications occurring intraprocedural or before discharge. Most major complications occurred intraprocedurally or within 6 h after the procedure (n = 96, 1.8%). Twelve (0.2%) major complications occurred between 6 h Postablation and discharge. The most common of these major complications were congestive heart failure (n = 6) and transient ischemic attack (TIA, n = 4). During this time span, 61 (1.1%) minor complications occurred. Factors independently associated with major complications intraprocedurally and until discharge were body mass index (BMI) ≥ 30 kg/m2 (p = .009), significant valvular disease (p = .001), cardiomyopathy (p < .001), prior stroke or TIA (p = .014), first-time procedure versus repeat procedure (p = .013), cryoablation versus radiofrequency (p < .001), and procedure duration (p < .001). CONCLUSION: After AF ablation, very few complications occurred between 6 h postprocedure and discharge the next day. Therefore, same-day discharge is a safe option for a majority of patients.

The results of health-related quality of life assessment depend on the prevailing rhythm at the assessment: Experience from the CAPTAF trial (Catheter Ablation Compared with Pharmacological Therapy for Atrial Fibrillation).

AIMS: To assess whether the prevailing rhythm at the time of replying to symptom and health-related quality of life (HR-QoL) questionnaires impacts the findings. METHOD: A total of 150 patients from the randomized Catheter Ablation Compared with Pharmacological Therapy for Atrial Fibrillation-trial, comparing atrial fibrillation (AF) ablation versus drugs, were included. The effect of the prevailing rhythm on the outcome results of the HR-QoL 36-Item Short-Form Health Survey, the symptom severity questionnaire (SSQ), and the European Heart Rhythm Association (EHRA) score for classification of AF-related symptoms was assessed. RESULTS: AF as the prevailing rhythm was independently associated with a significantly lower Vitality score; 18.4 points lower (95% confidence interval -32.7 to -4.1, p = .01) compared with sinus rhythm when adjusted for AF burden, median duration of episode, number of episodes, beta-blocker use, type of AF, and sex. The presence of AF did not affect the General Health score compared with sinus rhythm, nor did it influence symptoms assessed by the SSQ or EHRA score. CONCLUSION: The observation that the presence of AF versus sinus rhythm when conducting HR-QoL tests had a negative impact on its outcome, leaving symptom-related questionnaires unaffected, implies that the prevailing rhythm should be taken into account when results of HR-QoL questionnaires are interpreted.

A case report about successful treatment of refractory ventricular tachycardia with ablation under prolonged haemodynamic support with extracorporeal membrane oxygenation.

BACKGROUND: In patients with severe left ventricular dysfunction, recurrent ventricular tachycardia (VT) non-responsive to antiarrhythmic therapies may cause further deterioration of cardiac function and haemodynamic instability. The use of extracorporeal membrane oxygenation (ECMO) in the setting of haemodynamically unstable VT may allow rhythm stabilization and can be effective in providing haemodynamic stability during VT ablation procedures. CASE SUMMARY: We describe the clinical course of a patient with ischaemic cardiomyopathy and recurrent VTs in the early post-myocardial infarction (MI) period. Nineteen days after MI, the patient started to experience recurrent attacks of VT, which became more frequent and non-responsive to medical treatment including amiodarone and lidocaine. The patient developed cardiogenic shock and a decision was made to institute ECMO. The patient was supported with ECMO for 32 days because of heart failure, refractory VT, and recurrent infections. An electrophysiological study was performed 4 days after ECMO initiation, which revealed a large scar area in the left ventricle. Radiofrequency energy was applied 69 times, rendering the VT non-inducible. Subsequently, VT attacks disappeared and the patient was weaned from ECMO after 32 days. The patient received a left ventricular assist device 5 days post-ECMO weaning and was then transplanted. DISCUSSION: There is still no evidence or guidelines regarding patients with refractory VT; however, ECMO support has been successfully used during VT ablation procedures. In this case report, VT ablation had a crucial role in treating the culprit arrhythmia while the implementation of ECMO allowed a complex ablation procedure to be completed safely.

Atrial fibrillation burden, episode duration and frequency in relation to quality of life in patients with implantable cardiac monitor.

AIMS: To assess the relation between atrial fibrillation (AF) characteristics and health-related quality of life (QoL), and which AF characteristic had the greatest impact. METHOD: The AF characteristics burden (percentage of time in AF), duration and number of AF episodes/month were obtained from implantable cardiac monitors during the 2-month run-in period in 150 patients included in the randomized CAPTAF trial comparing early ablation and antiarrhythmic drug therapy. The QoL was measured by the General Health and Vitality dimensions of the 36-Item Short-Form Health Survey. AF characteristics were analysed continuously and in quartiles (Q1-Q4). RESULTS: Greater AF burden (p = 0.003) and longer AF episodes (p = 0.013) were associated with impaired QoL (Vitality score only) in simple linear regression analyses. Greater AF burden was, however, the only AF characteristic associated with lower QoL, when adjusted for sex, type of AF, hypertension, heart rate above 110 beats per minute during AF, and beta-blocker use in multiple linear regression analyses. For every 10% increase in AF burden there was a 1.34-point decrease of Vitality score (95% confidence interval (CI) -2.67 to -0.02, p = 0.047). The Vitality score was 12 points lower (95% CI -22.73 to -1.27, p = 0.03) in patients with an AF burden > 33% (Q4) versus those with < 0.45% (Q1), but only in unadjusted analysis. CONCLUSION: AF burden had a greater impact on QoL (Vitality), than the duration and number of AF episodes, corroborating that AF burden may be the preferred outcome measure of rhythm control in trials including relatively healthy AF populations.

Sinus heart rate post pulmonary vein ablation and long-term risk of recurrences.

PURPOSE: Cather ablation is known to influence the autonomic nervous system. This study sought to investigate the association of sinus heart rate pre-/post-ablation and recurrences in patients with atrial fibrillation undergoing pulmonary vein isolation (PVI). METHODS: Between January 2012 and December 2017, data of 482 patients undergoing their first PVI were included. Sinus heart rate was recorded before (PRE), directly post-ablation (POST) and 3 months post-ablation (3 M). All patients were screened for atrial tachyarrhythmia recurrences during the one-year follow-up. RESULTS: In the total study cohort, the mean resting sinus heart rate at PRE [mean 57.9 bpm (95% CI 57.1-58.7 bpm)] increased by over 10 bpm to POST [mean 69.4 bpm (95% CI 68.5-70.3 bpm); p < 0.001] followed by a slight decrease at 3 M [mean 67.3 bpm (95% CI 66.4-68.2 bpm)] but still remaining higher compared to PRE (p < 0.001). This pattern was observed in patients with and without recurrences at POST and 3 M (both p < 0.001 compared to PRE). However, at 3 M the mean sinus heart rate was significantly lower in patients with compared to patients without recurrences (p = 0.031). In this regard, patients with a heart rate change < 11 bpm (PRE to 3 M) or, as an alternative parameter, patients with a heart rate < 60 bpm at 3 M had a significantly higher risk of recurrences compared to the remaining patients (Hazard ratio (HR) 1.82 (95% CI 1.32-2.49), p < 0.001 and HR 1.64 (95% CI 1.20-2.25), p = 0.002, respectively). CONCLUSION: Our study confirms the impact of PVI on cardiac autonomic function with a significant sinus heart rate increase post-ablation. Patients with a sinus heart rate change < 11 bpm (PRE to 3 M) are at higher risk for recurrences during one-year post-PVI.

Focal atrial tachycardia-the localization differences between men and women: A study of 487 consecutive patients.

OBJECTIVE: The preferential sites for focal atrial tachycardia (FAT) are mainly in the right atrium in both sexes. However, a limited number of studies have indicated that sex differences in the localization of FAT. This study investigated possible sex differences in the distribution of FAT in a large cohort of patients referred for ablation. METHODS: From 2004 to 2019, 487 patients (298 women) were referred to our institution for ablation of FAT. A standard electrophysiological study was conducted, and isoproterenol or atropine was given when needed. Conventional catheter mapping, electroanatomic contact mapping, and noncontact mapping were used to assess the origin of ectopic atrial tachycardia. RESULTS: Overall, 451 foci were successfully ablated in 436 patients (90%). Although the foci located along the crista terminalis were more common in women than in men (42% vs. 29%; p=0.023), the opposite were found in the foci located along the tricuspid annulus (5% vs. 11%; p=0.032) and the right atrial appendage (RAA) (1% vs. 3%; p=0.032). Other locations were similarly distributed in men and women. In addition, the presence of persistent FAT was more frequent in men than in women (22% vs. 5%; p<0.001). Finally, the difference in the induction pattern of FAT was also remarkable between sexes. CONCLUSION: The distribution of FAT in women and men is different. In addition, persistent FAT seems more often in men than in women. The different distribution, persistency, and induction pattern of FAT should be considered in the successful management of this type of tachycardia.

Long-term outcome of patients with invasive electrophysiology procedure-related cardiac tamponade.

AIMS: Iatrogenic cardiac tamponades are a rare but dreaded complication of invasive electrophysiology procedures (EPs). Their long-term impact on clinical outcomes is unknown. This study analysed the risk of death or serious cardiovascular events in patients suffering from EP-related cardiac tamponade requiring pericardiocentesis during long-term follow-up. METHODS AND RESULTS: Out of 19 997 invasive EPs at the Karolinska University Hospital between January 1998 and September 2018, all patients with EP-related periprocedural cardiac tamponade were identified (n = 60) and matched (1:3 ratio) to a control group (n = 180). After a follow-up of 5 years, the composite primary endpoint - death from any cause, acute myocardial infarction, transitory ischaemic attack (TIA)/stroke, and hospitalization for heart failure - occurred in significantly more patients in the tamponade than in the control group [12 patients (20.0%) vs. 19 patients (10.6%); hazard ratio (HR) 2.53 (95% confidence interval, CI 1.15-5.58); P = 0.021]. This was mainly driven by a higher incidence of TIA/stroke in the tamponade than in the control group [HR 3.75 (95% CI 1.01-13.97); P = 0.049]. Death from any cause, acute myocardial infarction, and hospitalization for heart failure did not show a significant difference between the groups. Hospitalization for pericarditis occurred in significantly more patients in the tamponade than in the control group [HR 36.0 (95% CI 4.68-276.86); P = 0.001]. CONCLUSION: Patients with EP-related cardiac tamponade are at higher risk for cerebrovascular events during the first 2 weeks and hospitalization for pericarditis during the first months after index procedure. Despite the increased risk for early complications tamponade patients have a good long-term prognosis without increased risk for mortality or other serious cardiovascular events.

Early recurrences of atrial tachyarrhythmias post pulmonary vein isolation.

AIMS: To investigate the significance of early recurrence (ER) of atrial tachyarrhythmias after pulmonary vein isolation (PVI) on the development of late recurrence (LR) and to redefine the blanking period during which an ER is considered nonspecific. METHODS: Data of 713 patients undergoing their first PVI for paroxysmal or persistent atrial fibrillation between January 2012 and December 2017 were included. All patients were followed-up for 12 months according to clinical and outpatient routine and were screened for any atrial tachyarrhythmia lasting >30 seconds occurring during the first 3 months postablation (ER) and after the 3 months blanking period (LR). RESULTS: Patients with ER compared to those without ER had significantly more LR (74.5% vs 16.5% vs, P < .001). The occurrence of ER during the first, second and third months showed increasing LR rates of 35.2%, 67.9%, and 94.8%, respectively (P < .001). Receiver operator characteristic analysis revealed a blanking period of 46 days with the highest sensitivity (68.1%) and specificity (96.5%). Later timing and longer time span of ER were independent predictors for LR in multivariable analysis. CONCLUSION: ER is a strong predictor for LR. Our study advocates a shortening of the post-PVI blanking period followed by a "gray zone" up to 3 months where individualized therapeutic decisions based on additional risk factors should be considered. We suggest that the ER time span might serve as such a predictor identifying patients at the highest risk for LR.

Effect of Catheter Ablation vs Antiarrhythmic Medication on Quality of Life in Patients With Atrial Fibrillation: The CAPTAF Randomized Clinical Trial.

Importance: Quality of life is not a standard primary outcome in ablation trials, even though symptoms drive the indication. Objective: To assess quality of life with catheter ablation vs antiarrhythmic medication at 12 months in patients with atrial fibrillation. Design, Setting, and Participants: Randomized clinical trial at 4 university hospitals in Sweden and 1 in Finland of 155 patients aged 30-70 years with more than 6 months of atrial fibrillation and treatment failure with 1 antiarrhythmic drug or ß-blocker, with 4-year follow-up. Study dates were July 2008-September 2017. Major exclusions were ejection fraction <35%, left atrial diameter >60 mm, ventricular pacing dependency, and previous ablation. Interventions: Pulmonary vein isolation ablation (n = 79) or previously untested antiarrhythmic drugs (n = 76). Main Outcomes and Measures: Primary outcome was the General Health subscale score (Medical Outcomes Study 36-Item Short-Form Health Survey) at baseline and 12 months, assessed unblinded (range, 0 [worst] to 100 [best]). There were 26 secondary outcomes, including atrial fibrillation burden (% of time) from baseline to 12 months, measured by implantable cardiac monitors. The first 3 months were excluded from rhythm analysis. Results: Among 155 randomized patients (mean age, 56.1 years; 22.6% women), 97% completed the trial. Of 79 patients randomized to receive ablation, 75 underwent ablation, including 2 who crossed over to medication and 14 who underwent repeated ablation procedures. Of 76 patients randomized to receive antiarrhythmic medication, 74 received it, including 8 who crossed over to ablation and 43 for whom the first drug used failed. General Health score increased from 61.8 to 73.9 points in the ablation group vs 62.7 to 65.4 points in the medication group (between-group difference, 8.9 points; 95% CI, 3.1-14.7; P = .003). Of 26 secondary end points, 5 were analyzed; 2 were null and 2 were statistically significant, including decrease in atrial fibrillation burden (from 24.9% to 5.5% in the ablation group vs 23.3% to 11.5% in the medication group; difference -6.8% [95% CI, -12.9% to -0.7%]; P = .03). Of the Health Survey subscales, 5 of 7 improved significantly. Most common adverse events were urosepsis (5.1%) in the ablation group and atrial tachycardia (3.9%) in the medication group. Conclusions and Relevance: Among patients with symptomatic atrial fibrillation despite use of antiarrhythmic medication, the improvement in quality of life at 12 months was greater for those treated with catheter ablation compared with antiarrhythmic medication. Although the study was limited by absence of blinding, catheter ablation may offer an advantage for quality of life. Trial Registration: clinicaltrialsregister.eu Identifier: 2008-001384-11.

Safety of fluoroscopy-guided transseptal approach for ablation of left-sided arrhythmias.

AIMS: The transseptal approach is used for left atrial access during the ablation of atrial fibrillation (AF) and other left-sided arrhythmia substrates. Transseptal puncture (TP) is commonly performed with fluoroscopic guidance, contrast injection, and pressure monitoring. In many centres, additional techniques [intracardiac echocardiography (ICE), transoesophageal echocardiography (TEE), radiofrequency needle] are used to facilitate TP but its use adds costs. In this retrospective study, we studied the safety and complication rate when TP was routinely done with fluoroscopic guidance, contrast injection, and pressure monitoring using ICE or TEE only in selected cases. METHODS AND RESULTS: This study analysed 4690 consecutive TP performed between 2000 and 2015: 3408 (72.6%) were ablation of AF, left-sided atrial flutter, or left-sided atrial tachycardia (non-AP group); 1153 (24.6%) were ablation of left-sided accessory pathway, AP group; and 129 (2.8%) were ablation of ventricular tachycardia. Transseptal puncture was done under fluoroscopy, pressure monitoring, and commonly using contrast media injection. In 27 procedures, ICE or TEE was used to guide the TP. We found 34 tamponades (Tx) that required pericardial drainage of which 28 (0.59%) could possibly be TP related and six could not. The total complication rate for all Tx was 0.72%. A higher rate of tamponades was observed in the AF (non-AP) group than in the AP group (0.88 vs. 0.17%, P < 0.02). The highest rate of tamponades was registered during the operators 51-100 cases, 1.3%, and decreased to 0.4% in cases 101-200, P = 0.04. CONCLUSION: TP can safely be done under fluoroscopy and pressure monitoring without routine use of additional techniques. With experience, operators should be able to further decrease complication rate.

Cryoablation of atrioventricular nodal re-entrant tachycardia: 7-year follow-up in 515 patients-confirmed safety but very late recurrences occur.

AIMS: Cryoablation is an alternative method to radiofrequency ablation for treatment of atrioventricular nodal re-entrant tachycardia (AVNRT). This study investigates the long-term safety and efficacy of cryoablation in AVNRT. METHODS AND RESULTS: We studied 515 consecutive patients (317 women, mean age 50 years, range 13-89 years) undergoing a first cryoablation for AVNRT between 2003 and 2008. Ablations were performed with a 6-mm Freezor Xtra catheter. Six patients were acute failures; 494 out of 509 (97%) primarily successfully ablated patients were followed up for a mean of 7.1 years (range 2-12 years). About 11% (54/494 patients) of patients had recurrences of the index arrhythmia. Time to recurrence varied from days to 9 years; 14 patients (3%) had recurrences later than 2 years, 8 patients (2%) later than 3 years, and 6 patients (2%) later than 4 years. Recurrence rate was higher in patients with slow-slow or fast-slow AVNRT (n = 24) compared with the common slow-fast variant (25 vs. 10%; P = 0.04). Recurrence rate was not higher in patients with residual slow pathway conduction (jump with or without echo beat, n = 199, 39%). Transient atrioventricular (AV) block of the first-, second-, or third-degree during ablation was observed in 45 patients but had no impact on the risk of AVNRT recurrence. No late AV block occurred. Single vs. multiple applications or total amount of cryoenergy delivered did not differ between patients with and without recurrences. CONCLUSION: Cryoablation in AVNRT is safe with a long-term efficacy of 88%; however, very late recurrences occur.

Impact of cavotricuspid isthmus morphology in CRYO versus radiofrequency ablation of typical atrial flutter.

OBJECTIVES: Cryoablation (CRYO) is an alternative to radiofrequency (RF) for catheter ablation of cavotricuspid isthmus (CTI)-dependent atrial flutter (AFL). We aimed to study whether different CTI morphologies had different impacts on procedural success for CRYO and RF. DESIGN: This study randomized 153 patients with CTI-dependent AFL (median age 65 years; range 34-82) to RF or CRYO (78 CRYO; 75 RF). Biplane angiography (RAO 30° and LAO 60°) was done before the ablation procedure and isthmuses were classified as straight (n = 81), concave (n = 43) or pouch-like (n = 29). RF was performed with a 3.5-mm open-irrigated tip catheter and CRYO was performed with a 9 F, 8-mm tip catheter. The ablation endpoint was bidirectional block of CTI. RESULTS: Acute procedural success was achieved in 70/75 patients in the RF group and in 72/78 patients in the CRYO group. With regard to CRYO or RF, acute procedural success rates were similar between the three isthmus types: straight: CRYO (92%) and RF (96%); concave: CRYO (92%) and RF (94%); and pouch-like: CRYO (94%) and RF (85%). There were no significant differences regarding success rate between the different morphologies in the CRYO or the RF group. The CTI was longer in patients with acute failure compared to the patients with acute success (38 ± 7 mm versus 33 ± 6 mm, p = 0.045). CONCLUSION: The CTI morphology did not influence the acute success rate for either the CRYO or the RF ablation of CTI-dependent AFL. A longer CTI was associated with a lower success rate regardless of energy source.

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.

Comparison of regular atrial tachycardia incidence after circumferential radiofrequency versus cryoballoon pulmonary vein isolation in real-life practice.

BACKGROUND: Postablation atrial tachycardia (AT) is a significant complication following radiofrequency (RF) pulmonary vein isolation (PVI). Cryoballoon (CB) ablation is an alternative technique for PVI that appears to have a low incidence of AT. No direct comparison between AT risk in RF and CB ablation has been made. OBJECTIVE: To compare the incidence and characteristics of ATs after PVI with RF and with CB ablation in patients with paroxysmal atrial fibrillation (AF). METHODS: All patients who underwent their first PVI between January 2006 and September 2012 using either RF or CB ablation were included. When a repeat ablation procedure for AT was performed, the arrhythmia was classified as typical cavotricuspid isthmus (CTI) flutter or left atrial tachycardia (LA-AT) based on invasive mapping procedure findings and ECG P-wave morphology. RESULTS: The study population consisted of 415 and 215 consecutive patients in the RF and CB groups, respectively. After a mean follow-up of 38 ± 21 months, 52 (8.3%) patients presented ATs (9.4% and 6% in the RF and CB groups, respectively; P = 0.15). Of those, 26 (4.1%) were classified as LA-AT with 20 (4.8%) in the RF group and 6 (2.8%) in the CB group (P = 0.23). In patients without a history of typical CTI flutter or CTI line (n = 458), the incidence for this type of arrhythmia during follow-up was 3.5%. CONCLUSION: In patients with paroxysmal AF undergoing either RF or CB PVI as the sole ablation strategy, the incidence of postprocedural AT was low and there was no significant difference between the 2 techniques.

Cryoablation of substrates adjacent to the atrioventricular node: acute and long-term safety of 1303 ablation procedures.

AIMS: Radiofrequency (RF) ablation is effective for ablation of atrial arrhythmias. However, RF ablation in the vicinity of the atrioventricular (AV) node is associated with a risk of inadvertent, irreversible high-grade AV block, depending on the type of substrate. Cryoablation is an alternative method. The objective was to investigate the acute and long-term risks of AV block during cryoablation. METHODS AND RESULTS: We studied 1303 consecutive cryoablations of substrates in the vicinity of the AV node in 1201 patients (median age 51 years, range 6-89 years) on acute and long-term impairment to the AV nodal conduction system. The arrhythmias treated were AV nodal reentrant tachycardias (n=1116), paraseptal and superoparaseptal accessory pathways (n=100), and focal atrial tachycardias (n=87). In 158 (12%) procedures, cryomapping (38 cases) or cryoablation (120 cases) were stopped due to transient AV block (first-degree AV block 74 cases, second-degree AV block 67 cases, and third-degree AV block 17 cases) after which another site was tested. Transient AV block occurred within seconds of mapping up to 3 min of ablation. The incidence of AV block was similar for different substrates. In most cases, AV nodal conduction was restored within seconds but in two cases transient AV block lasted 21 and 45 min, respectively. There were no cases of acute permanent AV blocks. No late AV blocks occurred during follow-up (mean 24 months, range 6-96 months). CONCLUSION: Cryoablation adjacent to the AV node carries a negligible risk of permanent AV block. Transient AV block during ablation is a benign finding.