Counterclockwise Atrial Flutter Research Articles

A Simple Score to Predict New-Onset Atrial Fibrillation After Ablation of Typical Atrial Flutter

BackgroundNew-onset atrial fibrillation (NeAF) is common after cavotricuspid isthmus-dependent counterclockwise atrial flutter (CCW-AFL) ablation. This study aimed to investigate a simple predictive model of NeAF after CCW-AFL ablation. MethodsFrom January 2013, to December 2017, consecutive patients receiving CCW-AFL ablation were enrolled from 3 centres. Clinical, echocardiographic, and electrocardiographic data were collected and followed. Patients from 2 centres and another centre were assigned into the derivation and validation cohorts, respectively. In the derivation cohort, logistic regression was performed to evaluate the ability of parameters to discriminate those with and without NeAF. A score system was developed and then validated. ResultsTwo hundred seventy-one patients (mean 59.7 ± 13.6 age; 205 male) were analyzed. During follow-up (73.0 ± 6.5 months), 107 patients (39.5%) had NeAF; 190 and 81 patients were detected in the derivation and validation cohorts, respectively. Hypertension, age ≥ 70 years, left atrial diameter ≥ 42 mm, P-wave duration ≥ 120 ms and the negative component of flutter wave in lead II ≥ 120 ms were selected as the final parameters. A weighted score was used to develop the HAD-AF score ranging from 0 to 9. In the derivation cohort, area under the receiver operating characteristic curve (AUC) was 0.938 (95% confidence interval [CI], 0.902-0.974), superior to those of currently used CHA2DS2-VASC (0.679, 95% CI, 0.600-0.757) and HATCH scores (0.651, 95% CI, 0.571-0.730) (P < 0.001). Performance maintained in the validation cohort. ConclusionsSix years after CCW-AFL ablation, 39.5% of patients developed NeAF. HAD-AF score can reliably identify patients likely to develop NeAF after CCW-AFL ablation.

Ablation of atrial flutter in a patient after Fontan procedure: a case report of challenging access to the common atrium

Abstract Background In patients with a total cavopulmonary connection in Fontan circulation, the access to the common atrium (CA) during a catheter ablation can be challenging, even in the presence of fenestration in an intra-atrial lateral tunnel (IALT). In our department, the fenestration is typically marked with metal clips (MCs). To the best of our knowledge, there is no previous report of balloonoplasty of clipped fenestration. Case summary A 19-year-old male with hypoplastic left heart syndrome (HLHS) was scheduled for catheter ablation of recurrent atrial tachycardia. He was diagnosed with HLHS prenatally and underwent a stepwise surgical palliation. Fontan circulation was completed with the creation of a fenestrated IALT. The fenestration was marked by four MCs. During the ablation procedure, the passage of the steerable sheath with mapping catheter to the CA was prevented by a small fenestration size and rigidness of the edges of the fenestration caused by the MCs. Multiple attempts to dilate the fenestration using a peripheric angioplasty balloon failed. Only angioplasty with the ‘balloon-against-dilator’ technique was finally successful. Activation map showed a counterclockwise atrial flutter in the CA; successful ablation was performed. Discussion We present a case of challenging access to the CA through a clipped fenestration in a polytetrafluoroethylene baffle for atrial tachycardia ablation. Even though a tunnel fenestration in Fontan patients facilitates access to the CA, the passage of a steerable introducer with a mapping catheter may be challenging due to diameter mismatch and the rigidity of its edges caused by MCs. The balloon-against-dilator technique might be helpful when conventional balloon angioplasty fails.

PO-04-081 ISOLATION OF PERSISTENT LEFT SIDED SUPERIOR VENA CAVA USING PULSED FIELD ABLATION

Pulmonary vein foci account for more than 90% of triggers for atrial fibrillation, most commonly treated with complete pulmonary vein isolation. Non–pulmonary vein triggers are the drivers of atrial fibrillation in a subgroup of patients. One such trigger is a persistent left superior vena cava (SVC), which may contain remnant muscular and pacemaker tissue carried over from embryonic life. However, reported complications of radiofrequency ablation of this structure are significant, including vein stenosis, tamponade and phrenic nerve injury. Pulsed field ablation is a promising new technology that may be uniquely suited to avoid such a complications. This case illustrates the first known application of pulsed field ablation of a left sided SVC. N/A The patient is a fifty-two year old male with a history of coronary artery disease and persistent atrial fibrillation refractory to medical therapy including rate and rhythm control strategies. He is status post multiple cardioversions with restoration to normal sinus rhythm for a relatively short period of time. The patient underwent an ablation procedure at which time it was discovered that he had an isolated persistent left sided SVC. Pulmonary vein isolation was performed using a combined radiofrequency and pulsed field ablation lattice tip catheter (Affera inc., Watertown, MA). Accordingly to study protocol, lesions were placed using radiofrequency anteriorly and pulsed field lesions posteriorly in the left atrium around the pulmonary veins resulting in complete isolation. The patient also developed a counterclockwise typical atrial flutter which was ablated. Given the propensity for triggers from the SVC, pulsed field ablation was performed by creating a circumferential lesion set superiorly beyond the left superior pulmonary vein region and inferiorly near the mid coronary sinus below the left inferior pulmonary vein. A linear lesion set connecting these two regions was also performed along the atrial portion of the coronary sinus, with subsequent confirmation of exit block and elimination of all local electrograms. In patients with persistent left SVC, pulsed field ablation is feasible without the risk of phrenic nerve injury or tamponade from excessive contact force. Further studies are necessary to examine whether the complications associated with LSVC isolation can be minimized.

PO-02-223 A SIMPLE SCORE TO PREDICT NEW-ONSET ATRIAL FIBRILLATION AFTER ABLATION OF CAVOTRICUSPID ISTHMUS-DEPENDENT COUNTERCLOCKWISE ATRIAL FLUTTER: A MULTICENTER PROSPECTIVE COHORT STUDY

New-onset atrial fibrillation (NeAF) is common after successful ablation of cavotricuspid isthmus-dependent counterclockwise atrial flutter (CCW-AFL). This study aimed to investigate a simple predictive model of NeAF after CCW-AFL ablation. From January 2013 to December 2017, consecutive patients receiving CCW-AFL ablation without previous atrial fibrillation were enrolled from three Chinese centers. Clinical, echocardiographic, and electrocardiographic data were collected and followed regularly. Patients from two centers and another center were assigned into the derivation cohort and validation cohort, respectively. In the derivation cohort, logistic regression was performed to evaluate the ability of the above parameters to discriminate those with and without NeAF. A score system was developed and then validated in the validation cohort. Two hundred seventy-one patients (mean 59.7±13.6 age; 205 male) were analyzed. During follow-up (73.0±6.5 months), 107 patients (39.5%) had NeAF. 190 (76 with NeAF, 40.0%) and 81 patients (31 with NeAF, 38.3%) were detected in the derivation and validation cohorts, respectively. Hypertension, age ≥70 years, left atrial diameter ≥42 mm, duration of P wave in lead II ≥120 ms and the negative component of flutter wave in lead II ≥120 ms were selected as the final predictive parameters. A weighted score based on these variables was used to develop the HAD-AF score ranging from 0 to 9. In the derivation cohort, area under the receiver operating characteristic curve (AUC) of HAD-AF score was 0.938 (95% CI 0.902-0.974), superior to those of currently used CHA2DS2-VASC (0.679, 95% CI 0.600-0.757) and HATCH scores (0.651, 95% CI 0.571-0.730) (P<0.001). Performance maintained in the independent validation cohort (AUC, 0.912; 95% CI 0.846-0.978). 39.5% of patients developed NeAF in 6 years after CCW-AFL ablation. HAD-AF score, based on easily obtained pre-ablation parameters, can reliably identify patients likely to develop NeAF after CCW-AFL ablation.

PO-02-226 NON-INVASIVE ELECTROCARDIOGRAPHIC IMAGING FOR THE CHARACTERIZATION OF COMPLEX ATRIAL TACHYARRHYTHMIAS

Non-invasive characterization of complex atrial tachyarrhythmias, regarding atrial flutter (AFL) and focal atrial tachycardia (AT) is challenging. Conventional electrocardiogram (ECG) faces several limitations. Planning a preprocedural strategy before AFL-AT catheter ablation (CA) is needed. To evaluate the diagnostic capacity of a novel non-invasive electrocardiographic imaging (ECGI) system that does not require previous CT or MRI cardiac imaging. 42 patients (27 males, CHA2DS2-VASc score 2±1, LVEF 54.5 ± 11.0 %, and LA area 31.3 ± 7.0 cm2) undergoing CA for AT-AFL were prospectively included in the study. Before the procedure, the ECGI system estimated the patient atria geometry using a 3D torso reconstruction and an artificial intelligence-based algorithm. Multiple electrocardiograms were recorded using a 64-electrodes vest during the CA procedure. The different diagnostic capacities of the periprocedural ECG and ECGI were assessed compared with endocavitary electroanatomical mapping (EAM) regarding three endpoints: (1) the involved atrial cavity, (2) the mechanism (focal or macro-reentry), and (3) the ablation target site defined as the area where the earliest activation was located for focal arrhythmias, and the precise anatomical pathway for macro re-entrant tachyarrhythmias. Regarding the ECG, endpoints were assessed based on validated algorithms by 2 different observers blinded from the diagnosis. 48 atrial tachyarrhythmias were evaluated and its characterization using this novel ECGI system was possible in 94% of the cases: directly for 36 arrhythmias and after decreasing ventricular response using vagal maneuvers for 9. ECGI obtained global accuracy to identify the involved atrial cavity of 92%, the mechanism of 90%, and the ablation target of 83% (Table). In challenging cases, such as in patients with a history of CA for atrial fibrillation and in patients without a final diagnosis of typical counterclockwise AFL, the accuracy of ECGI was consistent compared to the whole study population (Table). The ECGI diagnostic capacity significantly outclassed the ECG regarding the identification of the involved cavity (p<0.001), the mechanism (p<0.05), and the ablation target (p<0.001). ECGI could have prevented all unnecessary transseptal punctures (n=7), representing 28% of the overall punctures. This novel non-invasive ECGI system accurately characterizes complex atrial tachyarrhythmias (Figure) without needing previous CT or MRI cardiac imaging.

The characteristics of pre-excitation syndrome concomitant with atrial tachyarrhythmia and the effect of radiofrequency ablation.

Wolff-Parkinson-White (WPW) concomitant with atrial tachyarrhythmia (ATA) has not been systemically characterized. Detailed electroanatomical mapping of the right atrium (RA) and/or left atrium (LA) was performed using three-dimensional mapping and the accessory pathway (AP) was mapped. WPW syndrome with ATA was diagnosed in 11 patients (median age 60 years). The characteristic of unidirectional anterograde conduction over the AP was displayed in nine patients, six of whom were intermittent. Sustained atrial tachycardia, that is, counterclockwise atrial flutter (AFL) with a median tachycardia cycle length (TCL) of 225 (220-275) ms, was mapped in eight patients; furthermore, "figure 8" right atrial reentry was mapped with TCL 250ms in one patient with a surgical history of ventricular septal defect repair. The remaining two patients underwent mitral annulus-dependent AT after paroxysmal atrial fibrillation (PAF) ablation and LA micro-reentry AT, respectively. In four patients, the location of the APs was left posterior. Left-lateral APs were identified in four patients. The locations of the APs in the remaining three patients were the right posterior and middle septum. All ATAs and APs were successfully ablated. After a median follow-up of 37 (15-72) months, no anterograde conduction over the AP was recorded, new onset of PAF was recorded in three patients, and all of them underwent circumferential pulmonary vein isolation. WPW with concomitant ATA frequently had continuous anterograde conduction over the AP with a rapid ventricular rate. Most WPWs displayed the characteristic of unidirectional anterograde conduction.

Comparison of clockwise and counterclockwise right atrial flutter using high-resolution mapping

Abstract Background To the best of our knowledge, few studies have been performed that explore the electrophysiological differences between clockwise (CW) and counterclockwise (CCW) right atrial (RA) cavotricuspid isthmus (CTI)-dependent atrial flutter (AFL) using the high-resolution Rhythmia mapping system. Objectives. Accordingly, our prospective cohort study, sought to compare CW and CCW CTI-dependent AFL in preselected pure right AFL patients (pts) using the ultra-high-definition (ultra-HD) Rhythmia mapping system. The study also aimed to mathematically develop a cartography model based on automatic velocity RA measurements to identify electrophysiological AFL specificities. Methods and results Between October 2019 and July 2020, 33 patients were recruited. The mean age was 71±13 years old. No difference was found concerning clinical variables between CCW AFL and CW AFL or regarding left ventricular ejection fraction (LVEF) (55.5±10 vs. 56.6±12; p=0.76). The AFL cycle length was very similar (248±20 vs. 252±28 ms; p=0.6). The sinus venosus (SV) block line was present in 32/33 of cases (97%) and no significant difference was found between CCW and CW CTI AFL (100% vs. 91%; p=0.7). No line was localized in the region of the crista terminalis (CT). A superior gap was present in the posterior line in 14/31 (45.2%) but this was similarly present in CCW AFL, when compared to CW AFL (10/22 [45.5%] vs. (4/10 [40%]); p=0.9). When present, the extension of the posterior line of block was observed in 18/31 pts (58%) without significant differences between CCW and CW CI AFL (12/22 [54.5%] vs. (6/10 [60%]) (p=.9) The Eustachian ridge line of block was similarly present in both groups (82% [18/22] vs. 45.5% [5/11]; p=0.2). The absence of the Eustachian ridge line of block led to significantly slowed velocity in this area (28±10cm/s; n=8),and the velocities were similarly altered between both groups (26±10 [4/22] vs. 29.8±11cm/s [4/11]; p=0.6). We created mathematical, three-dimensional RA reconstruction-velocity model measurements. In each block localization, when the block line was absent, velocity was significantly slowed (≤20cm/s). A systematic slowdown in conduction velocity was observed at the entrance and exit of the CTI in 100% of cases. This alteration to the conduction entrance was localized at the lateral side of the CTI for the CCW AFL and at the septal side of the CTI for CW AFL. The exit-conduction alteration was localized at the CTI septal side for the CCW AFL and at the CTI lateral side for the CW AFL. The only differences between CW and CCW AFL concerned activation patterns. Conclusions The ultra-HD Rhythmia mapping system confirmed the absence of significant electrophysiological differences between CCW and CW AFL. The mechanistic posterior SV and Eustachian ridge block lines were confirmed in each arrhythmia. A systematic slowing down at the entrance and exit of the CTI was demonstrated in both CCW and CW AFL, but in reverse positions. Funding Acknowledgement Type of funding sources: None.

Comparison of clockwise and counterclockwise right atrial flutter using high-resolution mapping and automated velocity measurements.

Only few studies have been performed that explore the electrophysiological differences between clockwise (CW) and counterclockwise (CCW) right atrial (RA) cavotricuspid isthmus (CTI)-dependent atrial flutter (AFL) using the high-resolution Rhythmia mapping system. We sought to compare CW and CCW CTI-dependent AFL in pure right AFL patients (pts) using the ultra-high-definition (ultra-HD) Rhythmia mapping system and we mathematically developed a cartography model based on automatic velocity RA measurements to identify electrophysiological AFL specificities. Thirty-three pts were recruited. The mean age was 71 ± 13 years old. The sinus venosus (SV) block line was present in 32/33 of cases (97%) and no significant difference was found between CCW and CW CTI AFL (100% vs. 91%; p = .7). No line was localized in the region of the crista terminalis (CT). A superior gap was present in the posterior line in 14/31 (45.2%) but this was similarly present in CCW AFL, when compared to CW AFL (10/22 [45.5%] vs. 4/10 [40%]; p = .9). When present, the extension of the posterior line of block was observed in 18/31 pts (58%) without significant differences between CCW and CW CI AFL (12/22 [54.5%] vs. 6/10 [60%]; p = .9) The Eustachian ridge line of block was similarly present in both groups (82% [18/22] vs. 45.5% [5/11]; p = .2). The absence of the Eustachian ridge line of block led to significantly slowed velocity in this area (28 ± 10 cm/s; n = 8), and the velocities were similarly altered between both groups (26 ± 10 [4/22] vs. 29.8 ± 11 cm/s [4/11]; p = .6). We created mathematical, three-dimensional RA reconstruction-velocity model measurements. In each block localization, when the block line was absent, velocity was significantly slowed (≤20 cm/s). A systematic slowdown in conduction velocity was observed at the entrance and exit of the CTI in 100% of cases. This alteration to the conduction entrance was localized at the lateral side of the CTI for the CCW AFL and at the septal side of the CTI for CW AFL. The exit-conduction alteration was localized at the CTI septal side for the CCW AFL and at the CTI lateral side for the CW AFL. The ultra-HD Rhythmia mapping system confirmed the absence of significant electrophysiological differences between CCW and CW AFL. The mechanistic posterior SV and Eustachian ridge block lines were confirmed in each arrhythmia. A systematic slowing down at the entrance and exit of the CTI was demonstrated in both CCW and CW AFL, but in reverse positions.

Electrophysiologic evidence of epicardial connections between low right atrium and remote right atrial region or coronary sinus musculature: Relevance for catheter ablation of typical atrial flutter

The coronary sinus (CS) is surrounded by a myocardial coat with extensive connections to the left and right atria that contributes to the interatrial electrical connection. Whereas epicardial connections between CS musculature and the left atrium have largely been demonstrated, clinically relevant epicardial connections from the CS musculature toward the low right atrium (LRA) and epicardial connections between two regions of the right atrium remain questionable ( Fig. 1 ). Five patients underwent electrophysiology (EP) study for typical atrial flutter (AFl) using either conventional multipolar catheters (four patients) or three-dimensional high-density mapping system (one patient). All five patients had a similar sequence of events during the EP studies. After several cavotricuspid isthmus (CTI) radiofrequency (RF) applications, double potentials were recorded along the ablation line while tachycardia persisted. The right atrial activation pattern strongly suggested the presence of a complete endocardial CTI line of the block. Based on the detailed conventional atrial mapping, RF applications at the middle cardiac vein/CS ostium allowed sinus rhythm restoration in four patients. High-density mapping showed an early breakthrough site at the septal side of the ablation line, close to the CS ostium during counterclockwise AFl, in the fifth patient. RF applications at this site resulted in tachycardia termination. Our observations suggested the existence of epicardial fibers connecting the LRA with either the CS musculature or a remote right atrial region. When AFl ablation fails whereas evidence for the local endocardial block is observed, the operators should integrate this finding in the diagnosis and ablation strategy.

Electrophysiologic evidence of epicardial connections between low right atrium and remote right atrial region or coronary sinus musculature: Relevance for catheter ablation of typical atrial flutter.

The coronary sinus (CS) is surrounded by a myocardial coat with extensive connections to the left and right atria that contributes to the interatrial electrical connection. Whereas epicardial connections between CS musculature and the left atrium have largely been demonstrated, clinically relevant epicardial connections from the CS musculature toward the low right atrium (LRA) and epicardial connections between two regions of the right atrium remain questionable. Five patients underwent electrophysiology (EP) study for typical atrial flutter (AFl) using either conventional multipolar catheters (four patients) or three-dimensional high-density mapping system (one patient). All five patients had a similar sequence of events during the EP studies. After several cavotricuspid isthmus (CTI) radiofrequency (RF) applications, double potentials were recorded along the ablation line while tachycardia persisted. The right atrial activation pattern strongly suggested the presence of a complete endocardial CTI line of the block. Based on the detailed conventional atrial mapping, RF applications at the middle cardiac vein/CS ostium allowed sinus rhythm restoration in four patients. High-density mapping showed an early breakthrough site at the septal side of the ablation line, close to the CS ostium during counterclockwise AFl, in the fifth patient. RF applications at this site resulted in tachycardia termination. Our observations suggested the existence of epicardial fibers connecting the LRA with either the CS musculature or a remote right atrial region. When AFl ablation fails whereas evidence for the local endocardial block is observed, the operators should integrate this finding in the diagnosis and ablation strategy.

P1013Biannular atrial flutter: clinical and electrophysiological characterization by activation and entrainment

Abstract Introduction re-entry mechanisms around mitral and tricuspid annuli are frequent causes of left and right atrial flutter (AFt) respectively in patients with ipsilateral atrial pathology. However, clinical and electrophysiological characteristics of other types of atrial re-entries that could involve both AV annuli are less known. Purpose characterize biannular atrial flutters. Methods 4 patients with AFt were submitted for ablation (aged 30, 31, 58 and 61 yo; 2 females). All had a cardiac congenital disease with a prior surgical procedure: 3 atrial septal defects (ASD) with surgical repair and 1 with transposition of the great arteries (TGA) with Senning repair. The AFt had a cycle length (CL) of 290, 315, 330 y 340 ms respectively and 1:1 AV conduction in 3 of them. For the electrophysiological study, a multipolar catheter (20 or 24 poles) was placed in the right atrium (RA) in every patient, showing counterclockwise and clockwise activation in 1 and 3 patients, respectively. Coronary sinus (CS) activation was proximal to distal in one patient and distal to proximal in the other 2. No CS activation could be obtained in the patient with Senning repair. Results each AFt was mapped by entrainment from different sites of the RA, showing post-pacing intervals (PPI) similar to the CL of the AFt around the tricuspid annulus in all of them and also from proximal and distal CS in the 3 patients with ASD. Access to the native left atrium (LA) was achieved in the patient with Senning repair, showing PPIs around the mitral annulus that were similar to the LC of the tachycardia. In 2 patients the attempt to get to the LA through the interatrial septum (IAS) could not be achieved and was unattempted in the other one. Recordings and PPIs of the LA roof were obtained from the right branch of the pulmonary artery in 2 patients. Counterclockwise AFt and clockwise AFt by single biannular perimitrotricuspid rotation in 1 and 3 patients respectively. The AFt was ended and no reinduction was possible after radiofrequency application that achieved cavotricuspid isthmus block in all of the patients. Conclusions reentry around both AV annuli is possible as a single loop, counterclockwise or clockwise, of simultaneous rotation as a clinical mechanism of Aft. This type of AFt seems to be associated to absence or severe damage in the IAS.

56-18: Use of the Rythmia ™ system for mapping atrial flutter in univentricular heart after Fontan procedure

Methods: a 35 yo patient with previous intracardiac total cavopulmonary connection was referred for recurring AT despite antiarrhythmic drugs, after ablation of two right atrial incisional reentry three years ago. Because of surgical closure of the tricuspid valve and lack of fenestration of the conduit, access to the right atrium was only possible by retrograde catheterism through the left ventricle, left atrium then through an atrial septal defect. Results: High density mapping of both right and left atrium was performed during AT using the Orion catheter ™. A common counterclockwise atrial flutter (AF) was diagnosed. Access to the cavo-tricuspid isthmus (CTI) was possible after turning the RF catheter around the intracardiac conduit connecting the inferior vena cava to the pulmonary artery. RF ablation at the CTI (after RF applications in the subhepatic veins and inside the conduit) finally terminated the tachycardia. Conclusion: The Rythmia system™ allows high density mapping and precise activation mapping in post-Fontan univentricular hearts patients. Both atrium may be mapped with the Orion ™ catheter even after complicated retrograde access. Common AF may happen in these patients whose ablation may be difficult due to anatomical constraints.

Detection of sequential activation of left atrium and coronary sinus musculature in the general population

BackgroundThe direction of impulse propagation across the coronary sinus (CS) musculature (CSM) is an important piece of the mechanistic puzzle underlying atrial tachyarrhythmias. We hypothesized that in the general population, the sequence of left atrial (LA) to CSM electrograms recorded in the CS reflects the direction of impulse propagation over the CSM. MethodsWe studied 19 patients with atrioventricular (AV) reentrant tachycardia (RT) utilizing a left-sided accessory pathway (AP) and 21 patients with typical counterclockwise atrial flutter (AFL). Conduction through the CSM during AVRT and AFL is from the left atrial (LA) to the right atrial (RA) and from the RA to LA direction, respectively. CS recordings of retrograde conduction over the AP and of AFL were analyzed in search of far-field, LA potentials. ResultsAmong 19 patients with AP, LA potentials were visible in 7 (37%), all in an LA → CSM activation sequence, while among the 21 patients with AFL, LA potentials were visible in 14 (67%), all in a CSM-LA activation sequence (P<0.0001). The prevalence of LA potentials was similar between both study groups (P=0.1119), and the overall prevalence was 53%. ConclusionsFar-field LA potentials are often recorded in the CS during sequential LA and CSM activation in the general population. The timing of LA potentials in CS recordings reflected the direction of conduction across the CSM.

Entrainment pacingにて心房内ブロックの出現を認め, ブロックに伴う心房波間隔の延長に比例して心房波高が著明に増大した心房粗動の1例

Entrainment pacingにて心房内ブロックの出現を認め, ブロックに伴う心房波間隔の延長に比例して心房波高が著明に増大した心房粗動の1例

Cavotricuspid-Dependent Atrial Flutter in Patients With Prior Atriotomy: 12-Lead ECG Interpretation and Electroanatomical Characteristics.

The aim of this study was to describe the electrocardiogram (ECG) morphology and electroanatomical characteristics of counterclockwise tricuspid annular atrial flutter (CCWTA-AFL) in the patients with prior atriotomy. This retrospective study included 34 patients with CCWTA-AFL after cardiac surgery and 20 patients with typical CCWTA-AFL without prior surgery. For patients in the postsurgical group, 19 had single-loop CCWTA-AFL and 15 had a double loop CCWTA-AFL. For single loop CCWTA-AFL the F-wave in lead I was very flat in l7 of 19 patients. The F-wave morphology in the inferior leads and V1 were found to be similar to typical AFL in 14 of 19 patients. For double loop CCWTA-AFL, F-waves were positive in lead I in 13 out of 15 patients. A long isoelectric activation was measured between F-waves in most of the patients. The presence of isoelectric segments between F-waves suggested a double loop AFL, which had a sensitivity of 86.7% and a specificity of 100%. Moreover, flat F-waves in lead I suggested a single loop AFL, which had a sensitivity of 89.5% and specificity of 86.7%. All patients in the group without prior cardiac surgery had typical ECGs features of CCWTA-AFL. None of the patients showed isoelectric segments between F-waves in the inferior leads. The amplitudes of most of the leads were higher than those for single loop CCWTA-AFL in patients with prior surgery.

Contribution of atrial activation to the segment of the typical atrial flutter wave: an electro-anatomic insight into the electrocardiogram morphology

To investigate how the intra-cardiac activation was translates into the characterized flutter wave in patients with cavatricuspid isthmus-dependent counter-clockwise atrial flutter (CTI-AFL). A total of 15 hospitalized CTI-AFL patients (mean age: (60 ± 14) years old, 1 female) from October 2012 to February 2014 were enrolled in the study. The activation map was re-constructed during AFL rhythm for left atrium and right atrium using 3-dimensional mapping system. The flutter wave in surface electrocardiogram was analyzed in combination with the intra-cardiac activation. The mean left ventricular ejection fraction was (60.8 ± 6.6)%, and the left atrial diameter was (39.0 ± 3.4) mm. The mean tachycardia cycle length was (220 ± 24) ms. The activation map was completed in all cases. In inferior leads, the flutter wave was divided into three parts: slowly downward part, sharp downward part and the terminal positive part. The three parts corresponded to the fixed activation part of the macro-reentry. The distinctive flutter wave of CTI-AFL was determined by the unique macro-reentry activation in the right atrium. The activation of left atrium contributes to the downward part of the wave.

Catheter ablation of atrial arrhythmias in a patient with surgically corrected congenital heart disease and inferior vena cava interruption

A 15year old girl who underwent surgical correction of ventricular septal defect and patent ductus arteriosus ligation in childhood presented with atrial tachycardia of crista terminalis origin and counterclockwise atrial flutter. She also had associated interruption of inferior vena cava which continued as azygous vein and left superior vena cava which drained via coronary sinus into the right atrium. She underwent radiofrequency ablation of both the tachycardias via internal jugular vein and azygous vein approach using 3D electroanatomical mapping system.

Radiofrequency ablation of left atrial flutter mediated with double potentials in a seemingly normally structured heart

BackgroundLeft atrial flutter (left AFL) is common in patients who undergo atrial fibrillation ablation and cardiac surgery; however, few reports describe left AFL in detail in a seemingly normally structured heart, and the mechanisms of the occurrence of such arrhythmia are still not clear. We describe left AFL in patients without prior cardiac surgery or catheter ablation and discuss the electrophysiological characteristics that may explain the preferential generation and perpetuation of such tachycardia. Methods and resultsEleven patients with left AFL, who had no history of cardiac surgery or interventions, underwent electrophysiological studies and 3-dimensional electroanatomic mapping studies. Echocardiography revealed a relatively mild dilation of the left atrium, mild to moderate mitral regurgitation, and a normal left ventricular ejection fraction. The electroanatomic mapping during tachycardia showed a “reentrant” activation pattern in all patients. The mean tachycardia cycle length was 266±17ms. A single-loop reentrant circuit was identified in 7 patients. A counterclockwise left atrial flutter evolved around the mitral valve annulus in 6 patients. The tachycardia rotated around the left atrial anterior wall in 1 patient. Four patients exhibited a double-loop reentrant circuit with a “figure of 8” pattern reentry. Double potentials as the critical isthmus of the circuit were identified in the left atrial anterior wall near the mitral annulus which displayed a low-voltage area matched with the left atrium–aorta contiguity. The conduction velocity was significantly slower in the double-potential recording area than in the lateral mitral annulus (0.36±0.03m/s vs 0.74±0.12m/s; P<0.05). Successful ablation around the double-potential recording site caused an interruption of the tachycardia, and remained free of recurrence during a 12-month follow-up in all patients. ConclusionLeft AFL in patients without a history of surgery or ablation is rarely observed in clinical practice. The successful site of ablation was within the anterior wall near the mitral annulus showing the double potentials as the critical part of the reentrant circuit. This suggests that perhaps a double potential-targeted ablation may be effective for these patients.

An Unexpected Intracardiac Echocardiography Finding on the Cavotricuspid Isthmus

A 60-year-old male was referred for catheter ablation of symptomatic paroxysmal atrial fibrillation. The patient had a history of remote myocardial infarction presenting with cardiogenic shock and requiring emergent 4-vessel coronary artery bypass grafting, including a saphenous vein graft to the right coronary artery (RCA). Although he had no clinical history of atrial flutter, typical counterclockwise atrial flutter involving the cavotricuspid isthmus (CTI) was induced with atrial burst pacing after successful pulmonary vein isolation.

Catheter Ablation of Atrial Flutter in Patients With Left Ventricular Assist Device Improves Symptoms of Right Heart Failure

Persistent atrial flutter (AFL) in left ventricular assist device (LVAD) recipients can result in loss of AV synchrony, impaired ventricular filling and right heart failure (RHF). The authors report the largest series of HeartMate II (HMII) patients who developed AFL with decompensated RHF, which successfully resolved with AFL ablation. Eight patients with HMII LVAD (mean age, 57±12years) had medically refractory AFL, with 7 developing de novo AFL after LVAD implant (onset range, 2days-22months post-implant). Three patients developed recurrent syncope, 2 had inappropriate implantable cardioverter-defibrillator shocks, and 6 had new or escalating need for inotropes. All had features of decompensated RHF. Seven patients underwent electrophysiology testing where mapping confirmed typical counterclockwise AFL (mean AFL cycle length, 252±49ms) and radiofrequency ablation of cavotricuspid isthmus restored sinus rhythm in all patients. Complete resolution of symptoms and signs of RHF with improved quality of life were noted in all. No procedural complications were noted. During a mean follow-up of 9±5months, all patients remained free of atrial flutter. Catheter ablation of AFL in LVAD patients is safe and highly effective, resulting in immediate and significant improvement in symptoms of RHF, and should be considered first-line therapy for AFL in these patients.