The purpose of this EP wire survey was to examine current practice in the management of both cavotricuspid isthmus (CTI)-dependent and non-CTI-dependent atrial flutter (AFL) ablation amongst electrophysiologists in European and Canadian centres and to understand how current opinions vary from guidelines. The results of the survey were collected from a detailed questionnaire that was created by the European Heart Rhythm Association Research Network and the Canadian Heart Rhythm Society. Responses were received from 89 centres in 12 countries. The survey highlighted variability within certain aspects of the management of AFL ablation. The variability in opinion regarding other procedural details suggests a need for further research in this area and consideration of the development of guidelines specific to AFL. Overall, there is reasonable consensus regarding oral anticoagulation and the desired endpoints of ablation for patients with CTI-dependent AFL and for non-CTI-dependent AFL.
Introduction
Typical atrial flutter (AFL) is categorized as either typical counterclockwise AFL when the macro re-entrant circuit is dependent on the cavotricuspid isthmus (CTI) and uses this isthmus from the patients right to left or typical clockwise AFL when the macro re-entrant circuit is dependent on the CTI and uses this isthmus from the patient’s left to right. Atypical AFL is not dependent on the CTI and may be either macro re-entrant as in peri-mitral, left atrial roof dependent or scar related (from prior ablation or surgery) atypical AFL or micro re-entrant (≤2 cm in diameter) AFL, which often resemble a focal atrial tachycardias.1 Catheter ablation for the management of CTI-dependent AFL is considered to be a highly successful procedure with an acute success of approximately 97%2 and a recurrence probability of approximately 10% over 14 months.3 Nevertheless, the subsequent occurrence of atrial fibrillation (AF) is common following a catheter ablation for CTI-dependent AFL with reported incidences of 34–53% over 14 months 2 and up to 82% of patients over 5 years.4 Catheter ablation for non-CTI-dependent AFL is technically more difficult with a large range in reported success rates from 73–100% and reported recurrence probabilities of 7–53% depending on the underlying mechanism for the atypical AFL.5,6 As a result, CTI-dependent catheter ablation is considered to be useful in patients with AFL who are either symptomatic or refractory to drug therapy (Class I indication, level of evidence B) and for recurrent symptomatic non-CTI-dependent AFL after failure of at least one antiarrhythmic drug (Class I indication, level of evidence C).5,6 There are several technologies available for this procedure that would likely predict a wide range of variability of clinical practice in the periprocedural and procedural periods. The purpose of this EP wire survey was to examine current practice in European and Canadian centres performing these procedures in order to gain an understanding of real-world experience and to identify deficiencies in practice which may need to be further addressed.
Methods
Results from the survey were collected from a detailed questionnaire that was jointly created by the European Heart Rhythm Association (EHRA) Scientific Initiatives Committee and the Canadian Heart Rhythm Society (CHRS). The questionnaire was sent via the internet to the EHRA-EP Research Network Centres and all registered CHRS members. Responses were examined as pre-procedure, intra-procedure, and post-procedure practices for each of CTI-dependent and non-CTI-dependent AFL. Percentages are expressed with the denominator being according to the number of individuals who provided responses to each question. Statistical analysis by χ2 test and Fisher’s exact test were used to compare responses between Europe and Canada. A P-value ≤0.05 was considered to be statistically significant.
Results
Of 89 responses received from centres in 12 countries (59 from Canada and 30 from European countries), 77/89 (86%) were from a university hospital, 4/89 (5%) from a non-academic private hospital, and 8/89 (9%) from a non-academic public or other type of institution; 25/89 responses (28%) were from centres performing more than 500 ablations per year (for all types of arrhythmia), 37/89 responses (42%) were received from centres performing 300–500 ablations annually, 11/89 (12%) from centres performing 200–300 ablations per year, 11/89 responses (12%) were received from centres performing between 100 and 200 ablations per year, and 5/89 (6%) were from centres performing <100 procedures per year.
Pre-procedural management
Catheter ablation was considered to be a therapeutic option only after at least one electrical cardioversion by 44/88 (50%) of respondents for CTI-dependent AFL and by 65/88 (74%) of respondents for non-CTI-dependent AFL. Using ablation as first-line therapy was considered to be an appropriate option by 41/88 (47%) of respondents for CTI-dependent AFL and by 10/88 (11%) of respondents for non-CTI-dependent AFL. Failure of antiarrhythmic drug therapy was considered to be the indication for catheter ablation by 3/88 respondents (3%) for CTI-dependent AFL and by 13/88 respondents (15%) for non-CTI-dependent AFL. There was no significant difference in practice between Europe and Canada.
The details of periprocedural management of oral anticoagulant therapy with either vitamin K antagonists (VKAs) or non-VKA oral anticoagulants (NOACs) are summarized in Table 1 for both CTI-dependent and non-CTI-dependent AFL. For patients with CTI-dependent AFL oral anticoagulation was routinely prescribed for ≥3 weeks prior to catheter ablation by 42/89 respondents (47%) and for ≥4 weeks before ablation by 28/89 respondents (31%). For patients with non-CTI-dependent AFL, pre-procedural oral anticoagulation was routinely provided for ≥3 weeks by 43/89 respondents (48%) and for ≥4 weeks by 33/89 respondents (38%). Of the remaining respondents who did not routinely prescribe oral anticoagulation prior to catheter ablation for CTI-dependent and non-CTI-dependent AFL 14/89 (16%) and 11/89 (12%), respectively, only prescribed an oral anticoagulant for patients with a CHA2DS2-VASC score of ≥2, irrespective of whether the patient was in AFL or sinus rhythm. The remaining 5/89 (6%) and 2/89 respondents (2%) did not prescribe oral anticoagulant therapy in patients with CTI-dependent and non-CTI-dependent AFL, respectively.
Management of periprocedural anticoagulation for CTI-dependent and non-CTI-dependent AFL ablation
| CTI-dependent (n = 89) | Non-CTI-dependent (n = 89) | |
|---|---|---|
| Pre-procedural oral anticoagulant use | ||
| Not routinely used | 5/89 (6%) | 2/89 (2%) |
| ≥3 weeks only for high-risk patients (CHADS2-VASC ≥2) | 14/89 (16%) | 11/89 (12%) |
| ≥3 weeks routinely | 42/89 (47%) | 43/89 (48%) |
| ≥4 weeks routinely | 28/89 (31%) | 33/89 (38%) |
| Procedural VKA use | ||
| Not discontinued | 78/89 (87%) | 69/89 (78%) |
| Discontinued OAC and LMWH bridging | 7/89 (8%) | 14/89 (15%) |
| Other strategy | 4/89 (5%) | 6/89 (7%) |
| Procedural NOAC use | ||
| Continue throughout the ablation procedure | 31/89 (35%) | 19/89 (21%) |
| Hold NOAC for 24 h | 48/89 (54%) | 53/89 (60%) |
| Hold NOAC for 48 h | 7/89 (8%) | 11/89 (12%) |
| Other strategy | 3/89 (3%) | 6/89 (7%) |
| Post-procedural NOAC use | ||
| Immediately following procedure | 7/89 (8%) | 7/89 (8%) |
| 4 h post-procedure | 5/89 (6%) | 9/89 (10%) |
| 4–6 h post-procedure | 24/89 (26%) | 28/89 (31%) |
| 6–24 h post-procedure | 22/89 (25%) | 26/89 (29%) |
| Continue NOAC throughout ablation procedure | 31/89 (35%) | 19/89 (22%) |
| Long-term OAC therapy post-ablation | ||
| Discontinue immediately after ablation procedure | 2/89(2%) | 1/89 (1%) |
| OAC is used routinely 4 weeks after procedure | 4/89 (5%) | 4/89 (5%) |
| OAC is used routinely 3 months after procedure | 8/89 (9%) | 7/89 (8%) |
| OAC is used routinely >3 months after procedure | 5 89 (6%) | 14/89 (16%) |
| >4 weeks, history of AF | 18/89 (20%) | 11/89 (12%) |
| >4 weeks, high-risk patient (CHA2DS2-VASC ≥2) | 51/89 (57%) | 51/89 (57%) |
| Unknown | 1/89 (1%) | 1/89 (1%) |
| CTI-dependent (n = 89) | Non-CTI-dependent (n = 89) | |
|---|---|---|
| Pre-procedural oral anticoagulant use | ||
| Not routinely used | 5/89 (6%) | 2/89 (2%) |
| ≥3 weeks only for high-risk patients (CHADS2-VASC ≥2) | 14/89 (16%) | 11/89 (12%) |
| ≥3 weeks routinely | 42/89 (47%) | 43/89 (48%) |
| ≥4 weeks routinely | 28/89 (31%) | 33/89 (38%) |
| Procedural VKA use | ||
| Not discontinued | 78/89 (87%) | 69/89 (78%) |
| Discontinued OAC and LMWH bridging | 7/89 (8%) | 14/89 (15%) |
| Other strategy | 4/89 (5%) | 6/89 (7%) |
| Procedural NOAC use | ||
| Continue throughout the ablation procedure | 31/89 (35%) | 19/89 (21%) |
| Hold NOAC for 24 h | 48/89 (54%) | 53/89 (60%) |
| Hold NOAC for 48 h | 7/89 (8%) | 11/89 (12%) |
| Other strategy | 3/89 (3%) | 6/89 (7%) |
| Post-procedural NOAC use | ||
| Immediately following procedure | 7/89 (8%) | 7/89 (8%) |
| 4 h post-procedure | 5/89 (6%) | 9/89 (10%) |
| 4–6 h post-procedure | 24/89 (26%) | 28/89 (31%) |
| 6–24 h post-procedure | 22/89 (25%) | 26/89 (29%) |
| Continue NOAC throughout ablation procedure | 31/89 (35%) | 19/89 (22%) |
| Long-term OAC therapy post-ablation | ||
| Discontinue immediately after ablation procedure | 2/89(2%) | 1/89 (1%) |
| OAC is used routinely 4 weeks after procedure | 4/89 (5%) | 4/89 (5%) |
| OAC is used routinely 3 months after procedure | 8/89 (9%) | 7/89 (8%) |
| OAC is used routinely >3 months after procedure | 5 89 (6%) | 14/89 (16%) |
| >4 weeks, history of AF | 18/89 (20%) | 11/89 (12%) |
| >4 weeks, high-risk patient (CHA2DS2-VASC ≥2) | 51/89 (57%) | 51/89 (57%) |
| Unknown | 1/89 (1%) | 1/89 (1%) |
CTI, cavotricuspid isthmus; LMWH, low-molecular-weight heparin; NOAC, non-vitamin K antagonist oral anticoagulant; VKA, vitamin K antagonist.
Management of periprocedural anticoagulation for CTI-dependent and non-CTI-dependent AFL ablation
| CTI-dependent (n = 89) | Non-CTI-dependent (n = 89) | |
|---|---|---|
| Pre-procedural oral anticoagulant use | ||
| Not routinely used | 5/89 (6%) | 2/89 (2%) |
| ≥3 weeks only for high-risk patients (CHADS2-VASC ≥2) | 14/89 (16%) | 11/89 (12%) |
| ≥3 weeks routinely | 42/89 (47%) | 43/89 (48%) |
| ≥4 weeks routinely | 28/89 (31%) | 33/89 (38%) |
| Procedural VKA use | ||
| Not discontinued | 78/89 (87%) | 69/89 (78%) |
| Discontinued OAC and LMWH bridging | 7/89 (8%) | 14/89 (15%) |
| Other strategy | 4/89 (5%) | 6/89 (7%) |
| Procedural NOAC use | ||
| Continue throughout the ablation procedure | 31/89 (35%) | 19/89 (21%) |
| Hold NOAC for 24 h | 48/89 (54%) | 53/89 (60%) |
| Hold NOAC for 48 h | 7/89 (8%) | 11/89 (12%) |
| Other strategy | 3/89 (3%) | 6/89 (7%) |
| Post-procedural NOAC use | ||
| Immediately following procedure | 7/89 (8%) | 7/89 (8%) |
| 4 h post-procedure | 5/89 (6%) | 9/89 (10%) |
| 4–6 h post-procedure | 24/89 (26%) | 28/89 (31%) |
| 6–24 h post-procedure | 22/89 (25%) | 26/89 (29%) |
| Continue NOAC throughout ablation procedure | 31/89 (35%) | 19/89 (22%) |
| Long-term OAC therapy post-ablation | ||
| Discontinue immediately after ablation procedure | 2/89(2%) | 1/89 (1%) |
| OAC is used routinely 4 weeks after procedure | 4/89 (5%) | 4/89 (5%) |
| OAC is used routinely 3 months after procedure | 8/89 (9%) | 7/89 (8%) |
| OAC is used routinely >3 months after procedure | 5 89 (6%) | 14/89 (16%) |
| >4 weeks, history of AF | 18/89 (20%) | 11/89 (12%) |
| >4 weeks, high-risk patient (CHA2DS2-VASC ≥2) | 51/89 (57%) | 51/89 (57%) |
| Unknown | 1/89 (1%) | 1/89 (1%) |
| CTI-dependent (n = 89) | Non-CTI-dependent (n = 89) | |
|---|---|---|
| Pre-procedural oral anticoagulant use | ||
| Not routinely used | 5/89 (6%) | 2/89 (2%) |
| ≥3 weeks only for high-risk patients (CHADS2-VASC ≥2) | 14/89 (16%) | 11/89 (12%) |
| ≥3 weeks routinely | 42/89 (47%) | 43/89 (48%) |
| ≥4 weeks routinely | 28/89 (31%) | 33/89 (38%) |
| Procedural VKA use | ||
| Not discontinued | 78/89 (87%) | 69/89 (78%) |
| Discontinued OAC and LMWH bridging | 7/89 (8%) | 14/89 (15%) |
| Other strategy | 4/89 (5%) | 6/89 (7%) |
| Procedural NOAC use | ||
| Continue throughout the ablation procedure | 31/89 (35%) | 19/89 (21%) |
| Hold NOAC for 24 h | 48/89 (54%) | 53/89 (60%) |
| Hold NOAC for 48 h | 7/89 (8%) | 11/89 (12%) |
| Other strategy | 3/89 (3%) | 6/89 (7%) |
| Post-procedural NOAC use | ||
| Immediately following procedure | 7/89 (8%) | 7/89 (8%) |
| 4 h post-procedure | 5/89 (6%) | 9/89 (10%) |
| 4–6 h post-procedure | 24/89 (26%) | 28/89 (31%) |
| 6–24 h post-procedure | 22/89 (25%) | 26/89 (29%) |
| Continue NOAC throughout ablation procedure | 31/89 (35%) | 19/89 (22%) |
| Long-term OAC therapy post-ablation | ||
| Discontinue immediately after ablation procedure | 2/89(2%) | 1/89 (1%) |
| OAC is used routinely 4 weeks after procedure | 4/89 (5%) | 4/89 (5%) |
| OAC is used routinely 3 months after procedure | 8/89 (9%) | 7/89 (8%) |
| OAC is used routinely >3 months after procedure | 5 89 (6%) | 14/89 (16%) |
| >4 weeks, history of AF | 18/89 (20%) | 11/89 (12%) |
| >4 weeks, high-risk patient (CHA2DS2-VASC ≥2) | 51/89 (57%) | 51/89 (57%) |
| Unknown | 1/89 (1%) | 1/89 (1%) |
CTI, cavotricuspid isthmus; LMWH, low-molecular-weight heparin; NOAC, non-vitamin K antagonist oral anticoagulant; VKA, vitamin K antagonist.
If a patient was on a VKA, 78/89 (87%) and 69/89 (78%) of respondents continued this treatment through the procedure for CTI-dependent and non-CTI-dependent AFL, respectively. The remaining respondents either used low molecular weight heparin bridging or held the VKA with no bridging. For patients who were on an NOAC, administration was continued through the procedure by 31/89 (35%) and 19/89 (21%) of respondents for patients with CTI-dependent and non-CTI-dependent AFL, respectively. Of those who discontinued the NOAC prior to catheter ablation for CTI-dependent AFL, NOACs were held for 24 h by 48/89 respondents (54%) and for 48 h by 7/89 respondents (8%). For non-CTI-dependent AFL, NOACs were held for 24 h by 53/89 respondents (60%) and for 48 h by 11/89 respondents (12%). The remaining responses varied depending on the patient’s CHA2DS2-VASC score or creatinine clearance, for both CTI-dependent and non-CTI-dependent AFL. There were no significant differences in the use of oral anticoagulation between respondents from Europe and Canada apart from a greater continuation of NOAC use throughout the catheter ablation of CTI-dependent AFL in Europe (16/30 respondents, 53%) vs. 15/59 respondents (25%) in Canada, P = 0.0009.
Transoesophageal echocardiography (TEE) was routinely performed by 15/88 respondents (17%) for CTI-dependent and by 41/88 respondents (47%) for non-CTI-dependent AFL prior to or during a catheter ablation. Of those who did not routinely perform a TEE prior to a catheter ablation for typical CTI-dependent AFL 69/88 respondents (78%) only performed a TEE if the patient was in AFL prior to catheter ablation, if the NOAC had been held for ≥24 h prior to the procedure, or if the international normalized ratio (INR) was subtherapeutic in the 3 weeks before ablation for patients on a VKA. The remaining 4/88 respondents (5%) only performed a TEE in patients with a CHA2DS2-VASC score of ≥2. Of the respondents who did not routinely perform a pre-procedure TEE for non-CTI-dependent AFL, 40/88 (45%) only performed a TEE if the patient was in AFL prior to catheter ablation, if the NOAC had been held for at least 24 h prior to the procedure, or if the INR was below the therapeutic range during the 3 weeks prior to ablation for patients on a VKA. The remaining 5/88 respondents (6%) performed a TEE only in patients with a CHA2DS2-VASC score ≥2. Two of the 88 respondents (2%) performed a pre-procedural CT to rule out the left atrial appendage thrombus. There were no significant differences in responses between European and Canadian operators.
Procedural details
Region-specific comparison of treatment strategy in patients with history of AF for CTI-dependent AFL ablation in Europe (A) and Canada (B) and non-CTI-dependent AFL in Europe (C) and Canada (D). AF, atrial fibrillation; AFL, atrial flutter; CTI, cavotricuspid isthmus; PVI, pulmonary vein isolation.
Region-specific comparison of diagnostic catheter setup for CTI-dependent AFL ablation in Europe (A) and Canada (B) as well as ablation catheter choice for CTI-dependent AFL in Europe (C) and Canada (D) and non-CTI-dependent AFL in Europe (E) and Canada (F). CF, contact force; CS, coronary sinus; CTI, cavotricuspid isthmus; RA, right atrium; RV, right ventricle.
Mapping of the tachycardia using a multielectrode catheter or repositioning a bipolar catheter to assess the activation sequence was used by 61/68 respondents (90%) for CTI-dependent AFL and by 47/68 respondents (69%) for non-CTI-dependent AFL. Entrainment was used by 70/78 respondents (90%) to confirm the diagnosis of CTI-dependent AFL and by 73/78 respondents (94%) for non-CTI-dependent AFL.
For patients with CTI-dependent AFL, 54/83 respondents (65%) used a 4-mm irrigated non-contact force catheter, 11/83 (13%) used a 4-mm irrigated contact force catheter, 1/83 (1%) used a non-irrigated 4-mm catheter, and 17/83 respondents (21%) used an 8-mm catheter for the majority of their cases. For non-CTI-dependent AFL, 28/83 respondents (34%) used a 4-mm irrigated non-contact force catheter, 47/83 (57%) used a 4-mm irrigated contact force catheter, 3/83 (4%) used a 4-mm non-irrigated catheter, and 5/83 respondents (6%) used an 8-mm catheter for the majority of their cases. As shown in Figure 2, there was a significantly greater preference for the use of 8-mm ablation catheters in Europe compared with Canada for the catheter ablation of CTI-dependent AFL [9/25 respondents (36%) in Europe vs. 8/58 respondents (14%) in Canada; P = 0.021]. For non-CTI-dependent AFL ablation, there was a significantly greater preference for the use of 4-mm contact force catheters in Canada compared with Europe [9/25 respondents (36%) in Europe vs. 37/58 respondents (63%) in Canada; P = 0.019].
Bidirectional CTI block was used as the desired endpoint in ablation procedures for CTI-dependent AFL by 83/85 respondents (95%). The most common method of assessing for bidirectional block was by using multisite pacing with the ablation catheter by 74/76 respondents (97%); 47/76 (62%) of these respondents also used a multielectrode catheter and 45/76 respondents (59%) used double potentials along the ablation line.
For patients with non-CTI-dependent AFL, termination of the tachycardia with ablation alone was considered indicative of a successful ablation by 8/85 respondents (9%) whereas 17/85 respondents (20%) required non-inducibility of the clinical arrhythmia as an endpoint and 18/85 (21%) considered non-inducibility of any arrhythmia as an endpoint. The remaining 42/85 respondents (49%) considered block across an ablation line as a suitable endpoint. There were no differences in terms of endpoints for catheter ablation for CTI-dependent AFL and non-CTI-dependent AFL between Europe and Canada.
Post-procedural management
In patients in whom NOAC therapy was stopped before ablation, 7/89 (8%) of respondents would restart NOACs immediately after the procedure, 5/89 (6%) would restart NOACs 4 h after the procedure, 24/89 (26%) would restart NOAC therapy 4–6 h after the procedure, and 22/89 respondents (25%) would restart NOAC therapy from 6 to 24 h after the procedure. For non-CTI-dependent AFL, 7/89 respondents (8%) would restart NOAC therapy immediately after the procedure, 9/89 (10%) would re-initiate NOAC therapy 4 h after the procedure, 28/89 (32%) would restart NOAC therapy 4–6 h after the procedure, and 26/89 respondents (29%) would restart the NOAC therapy 6–24 h after the procedure. This practice did not vary significantly between responses from Europe and Canada.
For patients who had undergone an apparently successful CTI ablation, oral anticoagulation was routinely stopped at the time of the procedure by 2/89 respondents (2%), 4 weeks after the procedure by 4/89 (5%), 3 months after the procedure by 8/89 (9%), and more than 3 months after the procedure by 5/89 respondents (6%) irrespective of the patient’s CHA2DS2-VASC score. However, 18/89 respondents (20%) would recommend continuing oral anticoagulation indefinitely in patients with a history of AF and 51/89 respondents (57%) would recommend continuing oral anticoagulation indefinitely in such patients only if their CHA2DS2-VASC score is ≥ 2. For patients who underwent an apparently successful ablation for non-CTI dependent, 1/89 respondents (1%) routinely stop oral anticoagulation at the time of the procedure, 4/89 (5%) stop oral anticoagulation 4 weeks after the procedure, 7/89 (8%) stop oral anticoagulation 3 months after the procedure, and 14/89 (16%) stop oral anticoagulation more than 3 months after the procedure irrespective of the CHA2DS2-VASC score. In patients with a history of AF, indefinite continuation of oral anticoagulant therapy is recommended irrespective of the CHA2DS2-VASC score value by 11/89 respondents (12%), or only if the CHA2DS2-VASC score equals ≥2 (51/89 respondents, 57%). There were no differences between Europe and Canada in terms of the management of longer term oral anticoagulation in patients who had undergone catheter ablation for either CTI-dependent or non-CTI-dependent AFL.
Discussion
Given the high success and relatively low complication rates for CTI-dependent AFL catheter ablation should be considered in both symptomatic and recurrent AFL.5,6 Almost all respondents in this survey considered CTI ablation an appropriate therapy as either first line therapy or following at least one electrical cardioversion for AFL. The majority (almost 75%) of respondents also considered catheter ablation to be first line therapy for the treatment of non-CTI-dependent AFL. This likely reflects the fact that the majority of these tends to occur after a catheter ablation for AF with a high recurrence rate despite the use of antiarrhythmic drug therapy.
Patients with AFL are presumed to have a similar risk of thrombo-embolism to those with AF.3,7 The guidelines for oral anticoagulation in patients with AFL therefore recommend that oral anticoagulation for these patients should be identical to those undergoing catheter ablation for AF, i.e. a minimum of 4 weeks prior to (in all but the lowest risk patients) and 8 weeks following the ablation with the longer term decision should be based on the patients CHA2DS2-VASC score.8 Almost 80% of respondents recommended that they would commence oral anticoagulation at least 3 weeks prior to a catheter ablation for either CTI-dependent or non-CTI-dependent AFL. The majority of respondents (77%) in our survey also stated that they would continue with longer term oral anticoagulation in patient with either a history of AF or a higher CHA2DS2-VASC score which is in keeping with recommendations.
There is an overall lack of consensus on the periprocedural use of NOAC agents in the catheter ablation of AFL or AF. Although there are data for the use of safety of uninterrupted NOAC’s in AF ablations compared with uninterrupted VKA9, these studies are small and the lack of an overall recommendation is likely reflected by the variability in responses in this survey between individual operators and between continents with a higher number of respondents continuing NOAC usage during CTI ablation in Europe. The majority of respondents did not stop oral anticoagulation for >24 h prior to the procedure. If the last dose of NOAC is taken more than 36 h prior to catheter ablation, a TEE is recommended10 and this may explain why the majority of operators opted not to perform a TEE prior to catheter ablation for CTI-dependent and to a lesser extent non-CTI-dependent AFL.
In patients with a history of both AFL and AF, catheter ablation techniques targeting the right atrial isthmus for CTI-dependent AFL or pulmonary vein isolation for AF have been shown to achieve effective outcomes in the treatment of these arrhythmias.11 Nevertheless, the timing of consideration of the two procedures in patients with both arrhythmias is debated. In this survey, approximately two-thirds of operators stated that they would ablate AFL first and reassess the patient later irrespective of whether AFL was the predominant rhythm or not. The remaining one-third of operators stated that they would perform an ablation procedure for both typical flutter and AF during the same procedure. Given the high recurrence rate of AF in follow-up after an AFL ablation there may be merit in performing a combined procedure. This must be weighed against the potential for additional complications of a catheter ablation for AF in patients whose dominant clinical rhythm is AFL. Clearly, further studies are required in order to assess more precise risk factors for development of AF after an AFL ablation.
Approximately 80% of the responding operators use an irrigated 4-mm catheter for the ablation of CTI-dependent AFL with the majority of the remaining operators using an 8-mm catheter. Just over 10% of operators are currently using contact force catheters for a CTI ablation. The use of contact force irrigated 4-mm catheter was considered by almost 60% of operators for use in the ablation of non-CTI-dependent AFL. There is no evidence to suggest that 8-mm catheters are more efficacious than 4-mm irrigated catheters for the treatment of AFL.12 Although there is evidence of an advantage to the use of contact force catheters in performing AF catheter ablations by virtue of a lower probability of acute pulmonary vein reconnection,13 similar data are lacking for both CTI-dependent and non-CTI-dependent AFL ablations.
Conclusion
The results of this survey show some variability in clinical practice among operators with respect to the periprocedural and procedural details of catheter ablation for patients with AFL. There is reasonable consensus regarding oral anticoagulation and the desired endpoints of ablation for patients with CTI-dependent AFL and for non-CTI-dependent AFL. The variability in opinion regarding other procedural details speaks to the need for further research and a consideration to develop guidelines in this area.
Acknowledgements
The production of this EP Wire document is under the responsibility of the Scientific Initiative Committee of the EHRA: Nikolaos Dagres (chair), Tatjana S. Potpara (co-chair), Serge Boveda, Jian Chen, Jean Claude Deharo, Dan Dobreanu, Stefano Fumagalli, Kristina Haugaa, Torben Bjeregaard Larsen, Radosław Lenarczyk, Antonio Madrid, Elena Sciaraffia, Milos Taborsky, and Roland Tilz. Document reviewer for EP-Europace: Irene Savelieva (St George’s University of London, London, UK). The authors acknowledge the EHRA Research Network centres participating in this EP Wire. A list of the Research Network can be found on the EHRA website. We would like to acknowledge all members and participants of the Canadian Heart Rhythm Society.
Conflict of interest: none declared.
