Higher Rate of Recurrent Atrial Flutter and Atrial Fibrillation Following Atrial Flutter Ablation After Cardiac Surgery

Atrial Flutter After Cardiac Surgery . Introduction: Atrial flutter (AFL) is common after cardiac surgery. However, the types of post‐cardiac surgery AFL, its response to catheter‐based radiofrequency ablation, and its relationship to atrial fibrillation (AF) are unknown. Methods and Results: We retrospectively studied all patients who underwent mapping and ablation for AFL after cardiac surgery from January 1990 to July 2004. One hundred randomly selected patients without prior cardiac surgery (PCS) who underwent mapping and ablation of AFL served as the control population. A total of 236 patients formed the study population (mean age 62 + 13 years, 22% female) and 100 patients formed the control population (mean age 60 + 13 years, 25% female). The majority of patients without PCS had cavo‐tricuspid isthmus (CTI)‐dependent AFL when compared to patients with PCS (93% vs 72%, respectively, P < 0.0001). In contrast, scar‐related AFL was more common in patients with PCS as compared to patients without PCS (22% vs 3%, P < 0.0001). Predictors of scar related AFL in multivariable regression analysis included PCS and left‐sided AFL. Acute success rates and complications were similar between the groups. When compared to patients with AFL ablation without PCS, those that had AFL after PCS had higher rates of recurrence of both AFL (1% vs 12%, P < 0.0001; mean time to recurrence 1.85 years) and AF (16% vs 28%, P = 0.02; mean time to recurrence 2.67 years). Conclusion: Despite ablation of AFL, patients with PCS have a higher rate of AFL and AF when compared to patients without PCS who underwent ablation of atrial flutter during long‐term follow‐up. (J Cardiovasc Electrophysiol, Vol. pp. 760‐765, July 2010)     

Intravenous Adenosine to Predict Conduction Recurrence in Cavotricuspid Isthmus Early After Ablation of Typical Atrial Flutter: Myth or Reality?

Adenosine and Ablation of Typical Atrial Flutter. Introduction: Early recovery of conduction (ER) after cavotricuspid isthmus (CTI) ablation for typical atrial flutter (AFl) occurs in approximately 10% of the patients. If not recognized, ER might lead to AFl recurrences. In this study, we hypothesized that intravenous adenosine (iADO) can be used to predict ER in the CTI immediately after RF ablation and distinguish functional block from the complete destruction of the CTI myocardium. Methods: We prospectively included 68 consecutive patients (age: 65 ± 14 years; male: 78%) referred in our centers for AFl ablation. Immediately after bidirectional isthmus block validation, a bolus of iADO was given during continuous pacing from the proximal coronary sinus. Patients with functional block revealed under iADO (iADO+) and those without (iADO?) were subsequently observed for a 30‐minute waiting period (ER?) or until sustained recovery of the conduction through the CTI (ER+). Results: Seven patients presented a persistent recovery (ER+, 10.3%, mean time to recovery: 14 ± 9 minutes). None of them presented even a transient resumption of conduction under iADO (iADO+: 0). With univariate analysis, we identified a heavy patient weight (>95 kg) as a predictor of ER (sensitivity: 71%). Conclusions: Adenosine does not predict early recovery in the CTI after linear ablation for atrial flutter. We found that a patient weight over 95 kg predicted early recovery of conduction through the CTI with a sensitivity of 71%. (J Cardiovasc Electrophysiol, Vol. 23, pp. 1201–1206, November 2012)     

Ablation of Atrial Fibrillation at the Time of Cavotricuspid Isthmus Ablation in Patients With Atrial Flutter Without Documented Atrial Fibrillation Derives a Better Long‐Term Benefit

AF Ablation in Patients With Only Documentation of Atrial Flutter. Objectives: The aim of the study was to evaluate whether isolation of the pulmonary veins (PVs) at the time of cavotricuspid isthmus (CTI) ablation is beneficial in patients with lone atrial flutter (AFL). Background: A high proportion of patients with lone persistent AFL have recurrent episodes of atrial fibrillation (AF) after CTI ablation. However, the benefit of AF ablation in patients with only documentation of AFL has not been determined. Methods: Forty‐eight patients with typical lone persistent AFL (age 56 ± 6; 90% male) were randomized to CTI ablation (Group A; n = 25) or to CTI + PV isolation (PVI) (Group B; n = 23). In addition to PVI, some patients in group B underwent ablation of complex fractionated electrograms and/or creation of left atrial roof and mitral isthmus ablation line in a stepwise approach when AF was induced and sustained for more than 2 minutes. Mean follow‐up was 16 ± 4 months with a 48‐hour ambulatory monitor every 2 months. Results: There were no recurrences of AFL in either group. Six patients in group B (22%) underwent a stepwise ablation protocol. AF organized and terminated in 5 patients during ablation (83%). Complication rate was not significantly different among the groups. Twenty patients in group B (87%) and 11 patients in group A (44%) were free of arrhythmias on no medications at the end of follow‐up (P < 0.05). Conclusions: Ablation of AF at the time of CTI ablation results in a significantly better long‐term freedom from arrhythmias. (J Cardiovasc Electrophysiol, Vol. 22, pp. 34‐38, January 2011)     

Incremental Pacing for the Diagnosis of Complete Cavotricuspid Isthmus Block During Radiofrequency Ablation of Atrial Flutter

Incremental Pacing for the Diagnosis of Cavotricuspid Isthmus Block.   Background: Complete conduction block of the cavotricuspid isthmus (CTI) reduces atrial flutter recurrences after ablation. Incremental rapid pacing may distinguish slow conduction from complete CTI conduction block.
Methods and Results: Fifty-two patients (67 ± 9 years) undergoing 55 CTI ablation procedures were included. With ablation, double potentials (DPs) separated by an isoelectric line of ≥30 ms were obtained. Incremental atrial pacing (600–250 ms) was performed from coronary sinus (CS) and low lateral right atrium (LLRA). A <20 ms increase in the DPs distance during incremental pacing was indexed as complete CTI block. In 8 patients, an initial <20 ms DPs distance increase was noted; direct complete isthmus block was suggested and no additional ablation performed. In the remaining, the CTI line was remapped for conduction gaps and additional radiofrequency energy pulses applied. Complete block, as indexed by incremental pacing, occurred in 46 of 55 procedures, with one flutter recurrence (follow-up 8 ± 2 months): DPs interval variation of 116 ± 20 to 123 ± 20 ms (CS), P = 0.21; and 122 ± 25 to 135 ± 35 ms (LLRA), P = 0.17. The remaining 9 patients (persistent rate-dependent DPs increase) presented 3 flutter recurrences, P = 0.01: DP distance from 127 ± 15 to 161 ± 18 ms (CS), P < 0.001; and 114 ± 24 to 142 ± 10 ms (LLRA), P = 0.007.
Conclusion: Incremental pacing distinguishes complete CTI block from persistent conduction. Such identification, accompanied by additional ablation to achieve block, should minimize flutter recurrences after ablative therapy. (J Cardiovasc Electrophysiol, Vol. 21, pp. 33–39, January 2010)     

Early versus Late Atrial Fibrillation after Atrial Flutter Ablation

Introduction: Radiofrequency catheter ablation of atrial flutter (AFl) has high initial success with a 10–15% recurrence. Atrial fibrillation (AFib) after radiofrequency catheter ablation of AFl can occur but may be transient (lasting no more than four weeks). Methods: Of one hundred seventeen consecutive patients studied, one hundred and four consecutive patients with sustained, symptomatic AFl, as the predominant rhythm disturbance (some of whom had transient pre-ablation AFib), referred for radiofrequency catheter ablation, had clinical follow-up. All had evidence for successful AFl ablation. Patients were followed prospectively. Results: Over a mean follow-up of 28 months, 28 patients developed AFib after ablation of AFl [12 early AFib (<2 months) and 16 late AFib (>2 months)]. Seven of 12 (58%) patients in the early onset group reverted to normal sinus rhythm; none required long-term antiarrhythmic therapy. Only one (8%) developed permanent AFib. No patient in the late onset group remained in sinus rhythm without an antiarrhythmic drug. Three (19%) developed permanent AFib despite therapy among those with late onset AFib. Two (17%) patients with early onset AFib reverted to normal sinus rhythm with treatment versus 5 (31%) in the late onset group. Finally, only 2 patients (17%) with paroxysmal/persistent episodes of Afib from the early onset group stayed in normal sinus rhythm despite therapy, while 8 patients ( ± %) with paroxysmal/persistent AFib episodes from the late onset group required therapy to maintain normal sinus rhythm. Conclusion: Early onset AFib after ablation of AFl is likely to be transient and self-limited. Late onset AFib after ablation of AFl can persist and require chronic therapy.     

Electrocardiographic and Electrophysiologic Characterization of Atypical Atrial Flutter in Man:

Atypical Atrial Flutter. Introduction : Although the circuit in typical counterclockwise atrial flutter has been clearly delineated, the mechanisms of "atypical atrial flutters" have been less well characterized. The purpose of this study was to investigate the ECG and electrophysiologic (EP) characteristics of atypical atrial flutter.
Methods and Results : Thirty-three patients with at least one form of atypical atrial flutter underwent EP evaluation with multipolar atrial activation and entrainment mapping. Nineteen patients with clockwise flutter had: (1) stereotypic ECG morphology; (2) same cycle length as counterclockwise flutter; (3) clockwise activation around the tricuspid annulus; (4) recording of discrete split potentials along the length of the crista terminalis, suggesting the presence of conduction block; (5) concealed entrainment from the low right atrial isthmus; (6) successful ablation in this isthmus. Twenty patients with atypical flutter not consistent with a clockwise mechanism ("true atypical flutter") showed: (1) heterogeneous ECG morphology; (2) cycle length shorter than that of clockwise flutter; (3) frequent transitions from and to atrial fibrillation; (4) could be entrained in only six patients and, when accomplished, demonstrated surface fusion when entraining from the low right atrial isthmus.
Conclusions : Atypical flutter falls into two broad categories. Clockwise flutter uses the same circuit with the same endocardial barriers as its counterclockwise counterpart and is best con sidered a form of typical flutter. True atypical flutter induced in the EP laboratory is a hetero geneous group of arrhythmias that are transitional to atrial fibrillation. Although it may superficially resemble clockwise or counterclockwise flutter based on the 12-lead ECG alone, the distinction can be readily made from a combined evaluation including activation and entrainment mapping.     

Randomized Comparison of Multipolar,Duty‐Cycled,Bipolar‐Unipolar Radiofrequency Versus Conventional Catheter Ablation for Treatment of Common Atrial Flutter

Comparison of Radiofrequency Versus Conventional Catheter Ablation. Introduction: Radiofrequency (RF) catheter ablation has been established as an effective and curative treatment for atrial flutter (AFL). Approved methods include a drag‐and‐drop method, as well as a point‐by‐point ablation technique. The aim of this study was to compare the acute efficacy and procedural efficiency of a multipolar linear ablation catheter with simultaneous energy delivery to multiple catheter electrodes against conventional RF for treatment of AFL. Methods: Patients presenting to our department with symptomatic, typical AFL were enrolled consecutively and randomized to conventional RF ablation with an 8‐mm tip catheter (ConvRF) or a duty‐cycled, bipolar‐unipolar RF generator delivering power to a hexapolar tip‐versatile ablation catheter (T‐VAC) group. For both groups, the procedural endpoint was bidirectional cavotricuspid isthmus block. Results: Sixty patients were enrolled, 30 patients each assigned to ConvRF and T‐VAC groups. Total procedure time (40.2 ± 15.8 min vs 60.5 ± 12.7 min), energy delivery time (8.5 ± 3.7 min vs 14.7 ± 5.2 min), radiation dose (14.5 ± 3.5 cGy/cm² vs 31.7 ± 12.1 cGy/cm²), and the minimum number of RF applications needed to achieve block (4.2 ± 2.4 vs 8.9 ± 7.2) were significantly lower in the T‐VAC group. In 7 patients treated with the T‐VAC catheter, bidirectional block was achieved with less than 3 RF applications, versus no patients with conventional RF energy delivery. Conclusion: The treatment of typical AFL using a hexapolar catheter with a multipolar, duty‐cycled, bipolar‐unipolar RF generator offers comparable effectiveness relative to conventional RF while providing improved procedural efficiency. (J Cardiovasc Electrophysiol, Vol. 21, pp. 1109‐1113)     

Right Coronary Artery Occlusion During RF Ablation of Typical Atrial Flutter

RCA Occlusion During RF Ablation . Right coronary artery (RCA) occlusion and acute myocardial infarction are rare during radiofrequency (RF) ablation of the cavotricuspid isthmus. Ventricular fibrillation (VF) or cardiac arrest in the periprocedural period may be the initial or only clinical manifestation. Septal or lateral RF delivery may increase the risk. We report 2 cases of RCA occlusion during ablation of typical atrial flutter (AFL). Angiographic and anatomical correlations are illustrated. One patient was ablated with a septal approach, the other with a lateral approach, and in each instance the RCA occluded near the ablative lesions. If septal or lateral ablation lines are contemplated during ablation of isthmus‐dependent atrial flutter, fluoroscopic or electroanatomic confirmation of catheter position is pivotal. Smaller tipped catheters, energy titration (to minimally effective dose), saline irrigation, or cryoablation should also be considered to help avoid this serious complication. (J Cardiovasc Electrophysiol, Vol. pp. 818‐821, July 2010)     

Identification of Extremely Slow Conduction in the Cavotricuspid Isthmus During Common Atrial Flutter Ablation

Introduction: Complete isthmus block has been used as an endpoint for radiofrequency ablation for common atrial flutter (AF). We sought to systematically evaluate extremely slow conduction (ESC), which is easily misinterpreted as complete block. Methods and Results: We studied 107 consecutive patients (92 men, 15 women, 58 ± 11 years) who had undergone a successful AF ablation procedure. A 24-pole catheter was positioned along the tricuspid annulus spanning the isthmus. Complete isthmus block was defined as the presence of a complete corridor of double potentials along the ablation line. Activation delay time (AT), activation difference (A) between two adjacent dipoles, maximum activation difference (A _max), change in polarity (CP) and change in amplitude (CA) of the bipolar atrial electrogram were recorded and P-wave morphology in the surface electrocardiogram was analyzed. ESC was observed in 16 patients. Between ESC and complete block, differences were found on the two lateral dipoles adjacent to the ablation line (AT: 148 ± 17 vs. 183 ± 27 ms and 155 ± 18 vs. 170 ± 28 ms, P < 0.01; A: –91 ± 22 vs. –126 ± 28 ms and –7 ± 13 vs. 13 ± 6 ms, P < 0.01). Statistically significant differences in CP were detected on the relevant dipoles (7/16 vs. 14/16 and 6/16 vs.13/16, P < 0.05). No significant difference was found either in CA or in terminal P wave positivity. Mean A _max were 13.8 ± 5.0 and 27.8 ± 9.5 ms (P < 0.001) respectively in ESC and complete block. Two types of ESC, regular and irregular, were demonstrated during the ablation procedure. Conclusions: (1) ESC was observed in 15% of the patients during the AF ablation procedure. (2) The parameters of AT, A, and CP may help to differentiate ESC from complete block. A _max might be the most powerful indicator. (3) To verify complete block, it is essential to position the mapping catheter across the CTI in order to demonstrate the activation sequence up to the ablation line.     

Radiofrequency Ablation of Atrial Flutter

RF Ablation of Atrial Flutter. Activation mapping in common atrial flutter has shown circular (reentrant) activation of the right atrium around anatomic structures and areas of functional block. The direction of rotation is counterclockwise (in a frontal view), and in the low right atrium the myocardium between the inferior vena cava (IVC) and the tricuspid valve (TV) is critical to close the activation circle. The circuit can be interrupted by radiofrequency ablation of the myocardium between the TV and the IVC, and, in some cases, by ablation between the coronary sinus and TV. Flutter interruption does not mean complete isthmus ablation, as it may remain inducible, requiring further ablation. Despite attaining noninducibility, flutter may recur, and new procedures may be needed for complete ablation. Atrial fibrillation occurs in up to 30% of the cases during follow-up but is generally well controlled with antiarrhythmic drugs that were ineffective in treating flutter before ablation. Some noncommon atrial flutters show circular right atrial activation in a reversed (clockwise) direction, with the same critical areas in the low right atrium, and in these isthmus ablation is effective. Other noncommon flutters have different substrates in the right or left atrium, and mapping has to define specific critical isthmuses as ablation targets in each case. Left atrial flutter circuits remain inaccessible to ablation.     

Spontaneous Transition from Atrial Fibrillation to Typical Atrial Flutter during Catheter Ablation of the Pulmonary Vein

A 71-year-old male patient was admitted for catheter ablation of the pulmonary veins to treat paroxysmal atrial fibrillation. Atrial fibrillation originating from the left superior pulmonary vein was induced after a pause of atrial pacing under isoproterenol infusion and became sustained. Spontaneous transition from atrial fibrillation to typical atrial flutter was noted after complete isolation of the pulmonary vein focus from the left atrium. Subsequently linear ablation of the cavotricuspid isthmus was created with completely bi-directional isthmus conduction block. We hypothesized that ectopic pulmonary vein focus played an important role in the spontaneous conversion of atrial fibrillation to typical atrial flutter, and complete isolation of the pulmonary vein could stop the spontaneous transition between the two atrial tachyarrhythmias.