Atypical atrial flutter ablation: clinical practice on patient selection, mapping, ablation strategies, and procedural endpoints—results from a European Heart Rhythm Association survey

Figures

• 

  Figure 1. Clinical profile and procedural factors associated with AAFl occurrence. (A) Most respondents reported that AAFl patients frequently have structural heart disease, prior cardiac surgery, or previous AF ablation. (B) Combined PVI with additional linear lesions was perceived as the AF ablation strategy most commonly associated with later AAFl. (C) Radiofrequency energy was most often considered the modality linked to AAFl recurrence, reflecting its widespread use for linear lesion creation. AAFI, atypical atrial flutter; AF, atrial fibrillation; CFAE, complex fractionated atrial electrograms; LAA, left atrial appendage; LVA, low-voltage area; PVI, pulmonary vein isolation; VoM, vein of Marshall.

• 

  Figure 2. Preferred timing and barriers to first-line ablation in AAFl. (A) Most respondents favoured early CA as first-line therapy for AAFl. (B) Among those not using ablation as first-line strategy, concerns included the risk–benefit balance, uncertainty about long-term efficacy, and limited operator or institutional resources. AAD, antiarrhythmic drugs; AAFI, atypical atrial flutter; ECV, electrical cardioversion.

• 

  Figure 3. Procedural strategies for AAFl ablation according to presenting rhythm and concomitant arrhythmias. (A) In patients with concomitant AF, most respondents combined AAFl ablation with PVI, whereas in patients with a history of AF, strategies were more evenly split between AAFl-only ablation and AAFl ablation combined with PVI. (B) In patients in sinus rhythm with non-inducible AAFl, the most common approach was combined PVI and voltage-guided substrate ablation, followed by empirical PVI alone or rescheduling the procedure. (C) When multiple AAFl were inducible, many respondents targeted all flutters, while others limited ablation to the clinically predominant AAFl or added adjunctive substrate ablation. AAFI, atypical atrial flutter; AF, atrial fibrillation; PVI, pulmonary vein isolation.

• 

  Figure 4. Pre-procedural cardiac imaging strategies in patients undergoing ablation for AAFl. Most respondents reported routine use of echocardiography (transoesophageal and transthoracic), whereas cardiac MDCT was used in roughly one-third of centres and late gadolinium-enhanced cardiac magnetic resonance was rarely employed. AAFI, atypical atrial flutter; LA, left atrium; LV, left ventricle; MDCT, multidetector computed tomography; MRI, magnetic resonance imaging; TOE, transoesophageal echocardiography; TTE, transthoracic echocardiography.

• 

  Figure 5. AAFl circuit mapping and anatomical considerations. (A) Activation mapping was ranked as the preferred method to confirm the circuit and select the first ablation site, whereas mid-diastolic signals and long or fractionated electrograms were least favoured. (B) In de novo left AAFl without prior cardiac interventions, the LAAW and mitral annulus were most frequently identified as part of the critical isthmus, followed by the LA roof and pulmonary veins. (C) Respondents estimated that macro-reentrant circuits account for the majority of AAFl cases, with localized reentry perceived as less common. AAFI, atypical atrial flutter; EGM, electrogram; LA, left atrium; LAA, left atrial appendage; LAAW, left atrial anterior wall; LAPW, left atrial posterior wall; PV, pulmonary vein.

• 

  Figure 6. Procedural endpoints in AAFl ablation: reported frequency of use and achievement rates. Most respondents reported routinely pursuing interruption of the clinical arrhythmia, validation of conduction block, and non-inducibility of the clinical flutter, and achieving these endpoints in >80% of cases, whereas non-inducibility of any atrial flutter was targeted and obtained less frequently. AAFI, atypical atrial flutter.