Mapping and ablation of left atrial roof-dependent tachycardias using an ultra-high resolution mapping system.

BACKGROUND: Left atrial roof-dependent tachycardias (LARTs) are common macroreentrant atrial tachycardias (ATs). We sought to characterize clinical LARTs using an ultra-high resolution mapping system. METHODS: This study included 22 consecutive LARTs in 21 patients who underwent AT mapping/ablation using Rhythmia systems. RESULTS: Three, 13, 4, and 2 LART patients were cardiac intervention naïve (Group-A), post-roof line ablation (Group-B), post-atrial fibrillation ablation without linear ablation (Group-C), and post-cardiac surgery (Group-D), respectively. The mean AT cycle length was 244 ± 43 ms. Coronary sinus activation was proximal-to-distal or distal-to-proximal in 16 (72.7%) ATs. The activation map revealed 13 (59.1%) clockwise and 9 (40.9%) counter-clockwise LARTs. A 12-lead synchronous isoelectric interval was observed in 10/19 (52.6%) LARTs. The slow conduction area was identified on the LA roof, anterior/septal wall, and posterior wall in 18, 6, and 2 ATs, respectively. Twenty concomitant ATs among 13 procedures were also eliminated, and peri-mitral AT coexisted in 7 of 9 non-group-B patients. In group-B, the conduction gap was predominantly located on the mid-roof. Sustained LARTs were terminated by a single application and linear ablation in 6 (27.3%) and 9 (40.9%), while converting to other ATs in 7 (31.8%) LARTs. Complete linear block was created without any complications in all, however, ablation at the mid-posterior wall was required to achieve block in 4 (18.2%) procedures. During 14.0 (6.5-28.5) months of follow-up, 17 (81.0%) and 19 (90.5%) patients were free from any atrial tachyarrhythmias after single and last procedures. CONCLUSIONS: The LART mechanisms were distinct in individual patients, and elimination of all concomitant ATs was required for the management.

Treatment of atrial tachycardia arising after superior transseptal approach mitral valve surgery: Insights from ultra-high-density mapping to prevent atrioventricular block.

INTRODUCTION: Mitral valve surgery employing a superior transseptal approach (STA) is associated with arrhythmogenicity and intra-atrial conduction delay, despite being optimal for visualization of the surgical field. It is sometimes difficult to treat atrial tachycardias (AT) that arise after STA. To investigate AT circuits that arise after STA in detail in order to identify the optimal ablation line, using ultra-high-resolution mapping (UHRM). METHODS: We retrospectively analyzed 12 AT from 10 patients (median age 70 years, nine males) who had undergone STA surgery. The tachycardias were mapped using the Rhythmia mapping system (Boston Scientific, Natick, Massachusetts). RESULTS: The 12 STA-related AT (STA-AT) circuits were classifiable as follows according to location of the optimal ablation line: (1) peri-septal incision STA-AT (n = 3), (2) cavotricuspid isthmus (CTI) dependent STA-AT (n = 7), and (3) biatrial tachycardia (n = 2). Radiofrequency (RF) application terminated 11 of the 12 STA-AT. We found that difference in STA-AT circuit type was due to characteristics of the septal incision line made for STA. UHRM was important in identifying optimal ablation sites that did not create additional conduction disturbances in the right atrium (RA). CONCLUSIONS: ATs after STA involve complex arrhythmia circuits due to multiple and long incision lines in the RA. Accurate understanding of the arrhythmia circuit and sinus conduction in the RA after STA is recommended for treating post-surgical tachycardia in a minimally invasive manner.

Perimitral atrial tachycardias dependent on residual nonligament of Marshall conduction.

INTRODUCTION: Catheter ablation for perimitral atrial tachycardia (PMAT) that persists despite lateral mitral isthmus (LMI) ablation is challenging. The aim of this study was to identify the role of the ligament of Marshall (LOM) in PMATs that persist after LMI conduction block has been created, and evaluate the validity of ethanol infusion into the vein of Marshall (VOM) as treatment. METHODS AND RESULTS: Sixteen consecutive PMATs in 13 patients that persisted despite apparent LMI conduction block, which was confirmed by ultrahigh-resolution mapping and entrainment pacing along the mitral annulus, were analyzed. PMATs were classified into two types based on the location of the endocardial breakthrough site: those utilizing the LOM (n = 13), which had a breakthrough site along with the LOM, and those not utilizing the LOM (n = 3), which had a breakthrough site at an anterior or posterior side of the LOM. Of the 16 PMATs, 5 PMATs (31%) were not suitable for ethanol infusion into the VOM because the LOM was not involved in the tachycardia circuit or because of the anatomy of the VOM. Fourteen PMATs (88%) were successfully terminated solely by breakthrough site ablation. At a mean follow-up period of 12 ± 9 months, 10 (77%) patients have remained free from atrial tachyarrhythmias. CONCLUSION: In cases of PMAT following LMI ablation, epicardial conduction over the LMI can occur independently of the LOM. Ethanol infusion into the VOM in such cases would not abolish residual epicardial conduction. The anatomy of the VOM can also preclude the use of this method.

Superior vena cava isolation with 50 W high power, short duration ablation strategy.

INTRODUCTION: The optimal ablation strategy is unknown regarding a superior vena cava isolation (SVCI). This study aimed to examine the feasibility and safety and to analyze the lesion characteristics of the SVCI using high-power, short-duration (HPSD) ablation. METHODS AND RESULTS: A total of 100 patients underwent an index SVCI using HPSD (n = 50, HPSD group) or conventional lower-power and longer-duration (n = 50, LPLD group) ablation, using the Thermocool Smarttouch SF. In the HPSD group, ablation was performed with a power of 50 W for 7 s, and was limited to 4 s at the lateral segment close to the right phrenic nerve. The ablation setting used in the LPLD group was 20-25 W for 20-30 s and was limited to 10-20 W for 15-30 s at the lateral segment when diaphragmatic capture was seen. An electrical SVCI was achieved in all patients. The HPSD group required a significantly shorter procedure time (10.8 ± 3.2 vs. 14.8 ± 6.4 min; p < .01), shorter radiofrequency duration (49 ± 16 vs. 282 ± 124 s; p < .01), fewer lesions (8.3 ± 2.5 vs. 10.4 ± 4.4; p < .01), and lower ablation index (316 ± 38 vs. 356 ± 62; p < .001) than the LPLD group. The incidence of a postprocedural asymptomatic mild diaphragmatic elevation was comparable (2% in the HPSD group vs. 6% in the LPLD group; p = .61). CONCLUSION: The 50-W HPSD ablation strategy allowed for a successful, fast, and safe SVCI with the fewer ablation lesions and the lower ablation index.

Features Suggesting Preferential Conduction in Pulmonary Artery Ventricular Arrhythmia for Identification of Successful Ablation Sites.

Radiofrequency catheter ablation (RFCA) for pulmonary artery ventricular arrhythmia (PAVA) can be difficult because of the occasional existence of PAVA with preferential conduction.This study described the characteristics of PAVA that demonstrate preferential conduction.We analyzed electrocardiographic and electrophysiological data from 8 patients found to have PAVAs with preferential conduction out of 183 patients (4.4%) with right ventricular outflow tract (RVOT) arrhythmias who underwent RFCA at our hospitals. The PAVA with preferential conduction were classified into two types. In type 1 PAVA, successful ablation sites (success-sites) exhibited discrete prepotentials with an isoelectric line, in which the activation time (AT) was ≥ 50 milliseconds. In type 2 PAVA, excellent pace mapping was achieved at two sites separated by ≥ 20 mm: one in the RVOT free wall and the other at the success-site in the pulmonary artery. Type 1 and 2 PAVA features were considered signs of a short and long preferential conduction pathway, respectively.There were four patients each with type 1 and 2 PAVA. Type 1 PAVA was distinguished by the isoelectric line at success-sites with the mean AT of 78 ± 25.1 milliseconds. In type 2 PAVAs, although the AT at RVOT sites was very short (18.5 ± 10.1 milliseconds), the AT at success-sites was longer than that at the RVOT by 42.3 ± 36.2 milliseconds. Type 2 PAVAs displayed distinct electrocardiogram (ECG) features (R wave in lead I, RR' in inferior leads, and transitional zone in V4) not found in typical PAVA ECGs.PAVA with preferential conduction can manifest in distinct ways on the ECG and intracardiac mapping. Knowledge of these features may facilitate successful RFCA of such PAVA cases.

Circulatory dynamics changes are an additional predictor of successful pulmonary vein isolation during cryoballoon ablation.

The association between circulatory dynamics changes during cryoballoon applications and a successful pulmonary vein isolation (PVI) is unknown. Seventy atrial fibrillation patients who underwent PVI with 28-mm second-generation cryoballoons and single 3-min freezes were included. Intra-procedural parameters including circulatory dynamics changes during cryoapplications, were compared between 113 successful applications (30 left superior PVs[LSPVs], 30 left inferior PVs[LIPVs], 25 right superior PVs[RSPVs], and 28 right inferior PVs[RIPVs]) and 47 failed applications (10 LSPVs, 9 LIPVs, 8 RSPVs, and 20 RIPVs). In all individual PVs, lower nadir balloon temperatures (MinTemps) and longer thawing times (ThawTimes) significantly predicted a successful PVI. In addition, greater systolic blood pressure drops following releasing the PV occlusion (SBP-drops) significantly predicted a successful right PV PVI, and longer elapse times during SBP-drops significantly predicted a successful RIPV PVI. Composite parameters incorporating MinTemps and ThawTimes, SBP-drops, and ThawTimes showed the highest area under the curve to predict a successful left PV (0.876 for LSPVs, 0.851 for LIPVs) and right PV (0.927 for RSPVs, 0.980 for RIPVs) PVI, respectively. If the ThawTime (≥ 30 s) and SBP-drop (≤ - 21 mmHg) cutoff values were achieved for the RIPVs, the positive predictive value was 100%. In contrast, if both criteria were not achieved for the RIPVs, the negative predictive value was 100%. In the second-generation cryoballoon PVI, the MinTemp and ThawTime were significantly associated with acute success for all four PVs. In addition, SBP-drops further improved the accuracy of predicting a successful right PV PVI, especially of the RIPV.

Perfect pace-mapping with different latencies from adjacent sites in bilateral outflow tract leading to successful sequential unipolar ablation.

A 77-year-old man with frequent monomorphic ventricular premature contractions (VPCs) was referred for catheter ablation. Detailed mapping just above the pulmonary valve (PV) revealed tiny fragmented potentials earlier than the VPC onset. Perfect pace-mapping was obtained using high voltage pacing just above the PV and the left aortic sinus of Valsalva, whose stimulus-to-VPC latencies differed by 20 ms. While the ablation at the pulmonary valve could not completely eliminate the VPCs, unipolar sequential ablation on both sides of the outflow tracts led to their successful abolition that was guided by perfect pace-mapping.

Utility of low-dose adenosine triphosphate sensitivity in slow-fast atrioventricular nodal reentrant tachycardia.

PURPOSE: Low-dose adenosine triphosphate (LD-ATP) is useful for diagnosing ATP-sensitive atrial tachycardia. However, the clinical implications of the sensitivity of LD-ATP in atrioventricular nodal reentrant tachycardia (AVNRT) still remain unknown. This study aimed to evaluate the mechanism of LD-ATP sensitivity in slow-fast AVNRT. METHODS: We estimated the sensitivity of LD-ATP in slow-fast AVNRT by a 2-4-mg ATP intravenous injection during the tachycardia. We evaluated the atrial-His (A-H) interval, tachycardia termination mode, prevalence of a lower common pathway (LCP), and successful ablation site in slow-fast AVNRT with LD-ATP sensitivity. LCPs were defined as His-atrial interval differences of at least 5 ms between that during ventricular pacing at the tachycardia cycle length and that during the tachycardia. RESULTS: Twenty-eight patients (mean age = 58 ± 11 years old, 18 females) with slow-fast AVNRT, who underwent catheter ablation of the antegrade slow pathway, were enrolled. Seventeen of 28 (61%) patients had LD-ATP sensitivity defined as termination of the tachycardia and/or a prolongation of the A-H interval of over 30 ms after an LD-ATP injection. The patients with LD-ATP sensitivity had a significantly higher prevalence of an LCP than those without (15/17 vs0/11, P < 0.0001). The successful ablation site in the LD-ATP sensitive group was significantly closer to the His bundle area than that in the LD-ATP nonsensitive group (13.3 ± 3.8 vs 20.5 ± 5.4 mm; distance to His bundle area in the left anterior oblique fluoroscopic view, P < 0.0001). CONCLUSIONS: LD-ATP sensitivity in slow-fast AVNRT may suggest the existence of an LCP. The successful ablation site in patients with LD-ATP sensitivity could be closer to the His bundle region.

Electrocardiographic morphology of multiple ventricular arrhythmias originating from the right ventricular outflow tract: inverse correlation of the amplitude in the inferior leads and anatomic height of the origin.

It is unclear whether the electrocardiogram amplitude in the inferior leads (Amp-I) can always predict the height of the origin of right ventricular outflow tract arrhythmias (RVOT-VAs). We analyzed patients who received catheter ablation of multiple RVOT-VAs in the same session in our hospital from 2011 to 2016. Two distinguished RVOT-VAs, those with anatomically higher origins (HOs) and lower origins (LOs), were identified and compared to measure the longitudinal distance. Amp-I was uniquely determined for each OTVA as the highest amplitude in leads II, III, and aVF and compared between the HO-VAs and LO-VAs. In total, out of 187 patients who underwent catheter ablation of RVOT-VAs, 9 (4.8%) had multiple right OTVAs successfully treated. Four cases (Group A) had HO-VAs (10.8 ± 5.3 mm from an LO) with a lower Amp-I (1.28 ± 0.46 mV) than the LO-VAs (1.81 ± 0.59 mV), whereas the other 4 patients (Group B) had HO-VAs with a higher Amp-I (1.91 ± 0.23 mV) than the LO-VAs (1.26 ± 0.35 mV). In Group A, all HO-VAs originated from the lateral free wall and had notched R waves in the inferior leads, whereas all LOs with higher Amp-Is were located on the septum. In one patient, the HO and LO were at almost the same height, while a VA from a lateral origin had lower notched R waves in the inferior leads. A divided excitation from high lateral origins may result in not only QRS notching, but also a reduction in the QRS amplitude. In patients harboring multiple RVOT-VAs, VAs arising from the high lateral free wall could have lower Amp-Is than VAs from low septal origins.

Simple and novel technique to confirm complete mitral isthmus block.

BACKGROUND: Differential pacing technique to confirm mitral isthmus (MI) block is sometimes challenging due to destroyed tissues after extensive ablation. The purpose of this study is to set an endpoint of MI ablation using conduction time around the mitral annulus (MA). METHODS: Forty-five consecutive patients with persistent atrial fibrillation who received MI linear ablation were included. The geometry and activation times of the left atrium around the MA were collected using a multipolar catheter before ablation. During coronary sinus (CS) pacing, the time between the stimulus and the wave-front collision at the opposite side of the MA (defined as T/2) was calculated, and the doubled value was defined as the estimated perimitral conduction time (E-PMCT). The endpoint for complete MI block was when the stimulus (at distal CS) minus the maximal delayed potential (St-MDP) on the MI interval reached the E-PMCT. RESULTS: St-MDP reached E-PMCT during MI ablation in 44/45 patients. Among these 44 patients, differential pacing revealed bidirectional block in 39/44 (88.6%), whereas in 5/44 (11.4%), the differential pacing was not possible because of the loss of capture of local potentials due to extensive applications around the linear line. In one patient, the St-MDP did not reach E-PMCT (E-PMCT: 148 ms, St-MDP :130 ms) and differential pacing revealed no MI block. E-PMCT values (median 176 ms) correlated strongly with St-MDP (median 185 ms, P < 0.0001, R = 0.98). CONCLUSIONS: Although E-PMCT differs between individuals, the value is significantly correlated with the St-MDP. This technique may be useful in providing an individual endpoint of MI ablation as an alternative to differential pacing.

The proportion of asymptomatic recurrence after catheter ablation of atrial fibrillation in patients with a pacemaker for sick sinus syndrome.

BACKGROUND: Catheter ablation (CA) of paroxysmal atrial fibrillation (PAF) is an effective treatment. However, the frequency of asymptomatic AF recurrence after CA in patients with PAF and sick sinus syndrome (SSS) is not clear. The aim of this study was to elucidate the real AF recurrence after CA in patients with PAF and a pacemaker for SSS. METHODS AND RESULTS: Fifty-one consecutive patients (mean age 66.6 ± 7.0 years, male 34) with PAF and SSS and pacemakers underwent CA. All patients were followed at 1, 3, 6, 9, and 12 months after the CA using a 12-lead ECG, Holter-ECG, and 1-month event recorder as a conventional follow-up. In addition, the pacemakers were interrogated every 12 months. During a 5-year follow-up after the final CA procedure, AF recurrences were observed in 7 patients (13.7%) with a conventional follow-up, including 1 (2.0%) asymptomatic patient. Pacemaker-interrogation revealed another 10 patients (19.6%) with asymptomatic AF recurrences. Ultimately, the conventional follow-up plus pacemaker-interrogation provided a higher incidence of AF recurrences (P = 0.009). Multiple CA procedures contributed to a significant increase in the AF-free survival rate at 5 years: 58.6% after a single CA and 86.0% after multiple CA procedures with a conventional follow-up, but which decreased to 40.6% and 60.9% with a conventional follow-up plus a pacemaker interrogation, respectively. CONCLUSIONS: One-third of PAF patients with SSS and pacemakers recurred after multiple CA sessions. However, 65% of them were asymptomatic and difficult to be identified with conventional follow-up. Pacemaker interrogation significantly increased the detection rate of AF-recurrence.

Rapid Mapping of Right Atrial Tachycardia Using a New Multielectrode Basket Catheter.

INTRODUCTION: The mapping of atrial tachycardia (AT) can often be challenging and time-consuming, especially in patients with ATs that develop following cardiac surgery or are concomitant with atrial fibrillation. Recently, a new multielectrode basket catheter (MBC) has become available; we hypothesized that the MBC could be utilized to diagnose AT circuits. METHODS AND RESULTS: This study included 51 consecutive patients undergoing catheter ablation of clinically documented right-sided ATs (including 17 cases following cardiac surgery). Using a NavX system, 2 activation maps of the ATs were created, one using the new MBC (32 mm, 31 poles) and the other using a circular catheter. The time needed to complete the activation maps and the points acquired with both mapping catheters were compared. In all 64 ATs, including 34 non-cavotricuspid isthmus-dependent ATs, the AT activation maps created by both catheters were essentially identical. The number of points acquired to complete the activation maps did not differ significantly between the MBC and the circular catheter (387 [285-511] vs. 374 [269-533], P = 0.19), but the mapping time was significantly shorter using the MBC (4.0 [3.0-6.0] minutes vs. 8.0 [6.5-10.0] minutes, P < 0.0001). Inadvertent mechanical AT termination (n = 6) was observed only during mapping with the circular catheter. CONCLUSION: In patients with right-sided ATs, the use of an MBC could save mapping time.

Impact of Non-Pulmonary Vein Foci on the Outcome of the Second Session of Catheter Ablation for Paroxysmal Atrial Fibrillation.

BACKGROUND: Paroxysmal atrial fibrillation (AF) is primarily triggered by pulmonary veins (PVs). However, non-PV AF foci may also trigger AF. METHODS: We examined 207 patients (mean age, 62 ± 11 years; 166 men) who underwent a second catheter ablation (CA) and evaluated the clinical significance of non-PV AF foci on the outcomes. RESULTS: Electrical reconnections between the PVs and left atrium (LA) were observed in 162 patients (78.3%). Non-PV AF foci were identified in 95 patients (45.9%, 60 patients with successfully ablated non-PV AF foci and 35 with unmappable non-PV AF foci). During a median follow-up period of 22.7 months, 61 patients (29.5%; 18/112 [16.1%] without non-PV AF foci vs. 20/60 [33.3%] with successfully ablated non-PV AF foci vs. 23/35 [65.7%] with unmappable non-PV AF foci, P < 0.0001) developed AF recurrence; 52 (85.2%) developed recurrence within 1 year. The presence of non-PV AF foci was a significant clinical predictor of AF recurrence after the second CA; successfully ablated non-PV AF foci increased the AF recurrence risk by 2.24 times (95% confidence interval [CI], 1.12-4.54; P = 0.02), and unmappable AF foci increased this risk by 5.58 times (95% CI, 2.73-11.63; P < 0.0001). CONCLUSION: Nearly half of the patients had non-PV AF foci at the second CA session. AF recurred after the second CA session in approximately 30%, with most recurrences happening within 1 year. The presence of non-PV AF foci significantly increased the AF recurrence risk after a second CA. When non-PV AF foci were unmappable, the AF recurrence rate was extremely high.

Simultaneous isolation of superior and inferior pulmonary veins on both the left and right sides could yield better outcomes in patients with paroxysmal atrial fibrillation.

AIMS: This study investigated whether disappearance patterns of pulmonary vein (PV) potentials (PVPs) during PV isolation (PVI) affect the outcome of catheter ablation (CA) in patients with paroxysmal atrial fibrillation (PAF). METHODS AND RESULTS: Extensive PVI was performed in 1149 PAF patients (age, 61 ± 10 years). Clinical and demographic characteristics, ablation data, and follow-up outcomes were prospectively collected. During an initial CA, simultaneous disappearance of superior and inferior PVPs in both right and left PVs was observed in 464 (40.4%) patients (Group S). Atrial fibrillation-recurrence free rates at 1, 3, and 5 years after the initial CA in Group S were 78.9, 71.9, and 68.1%, respectively, which were higher than those in Group Non-S (P = 0.004). However, those were similar after the final CA between both groups. The incidence of PV-left atrium (LA) electrical reconnection was significantly lower in Group S than in Group Non-S in the second (Group S, 65.6% vs. Group Non-S, 82.1%; P = 0.004) and third (Group S, 8.3% vs. Group Non-S, 47.6%; P = 0.03) CAs. Furthermore, the reconnections more frequently occurred on the side of PVs where simultaneous PVP elimination had not been achieved at the initial CA. Simultaneous disappearance of superior and inferior PVPs in both right and left PVs independently reduced the risk of AF recurrence after the initial CA by 26%. CONCLUSIONS: The simultaneous disappearance of superior and inferior PVPs in both right and left PVs is associated with less frequent PV-left atrium reconnection and may yield a better clinical outcome after the initial CA.

Oesophageal cooling with ice water does not reduce the incidence of oesophageal lesions complicating catheter ablation of atrial fibrillation: randomized controlled study.

AIM: Atrial fibrillation (AF) ablation can result in oesophageal injuries that lead to atrio-oesophageal fistulae, a life-threatening complication. This study aimed to evaluate whether oesophageal cooling could prevent oesophageal lesions complicating AF ablation. METHODS AND RESULTS: We randomly assigned 100 patients with drug-resistant AF to an oesophageal cooling group or a control group. In the oesophageal cooling group, we injected 5 mL of ice water into the oesophagus prior to radiofrequency (RF) energy delivery adjacent to the oesophagus. If the oesophageal temperature reached 42°C, the RF energy delivery was stopped, and the ice water injection was repeated. In the control group, oesophageal cooling was not applied. Oesophageal endoscopy was performed 1 day after the catheter ablation, and lesions were qualitatively assessed as mild, moderate, or severe. The numbers of ablation sites with an oesophageal temperature of >42°C were 1.7 ± 1.4 and 2.6 ± 1.7 in the oesophageal cooling group and the control group, respectively (P = 0.04), and the maximal oesophageal temperature at those sites was 43.0 ± 0.6 and 44.7 ± 0.9°C (P < 0.0001). Oesophageal lesions occurred almost equally between the oesophageal cooling group [10 of 50 patients (20%)] and the control group [11 of 50 patients (22%)]. However, the severity of the oesophageal lesions was slightly milder in the oesophageal cooling group (three moderate, seven mild) than in the control group (three severe, one moderate, seven mild). CONCLUSION: Oesophageal cooling may alleviate the severity of oesophageal lesions but does not reduce the incidence of this complication under the specific protocol evaluated here.

Late-phase thromboembolism after catheter ablation for paroxysmal atrial fibrillation.

BACKGROUND: The aim of this study was to investigate the incidence and predictors (which have not previously been fully elucidated) of late-phase thromboembolism (TE) after catheter ablation (CA) for paroxysmal atrial fibrillation (AF). METHODS AND RESULTS: We studied 1,156 consecutive patients (61±10 years; 891 men; CHADS2score, 0.8±1.0) after CA for symptomatic paroxysmal AF and examined the details of late-phase TE. During a follow-up of 49.5±21.9 months (median, 47 months; range, 6-113 months) after CA, 9 patients (0.78%) developed late-phase TE, all of which were ischemic stroke. Of these, 5 patients with AF recurrence experienced cardioembolism; the AF was asymptomatic at recurrence. The remaining 4 without AF recurrence experienced cardioembolism (n=1), small-vessel occlusion (n=1), large-artery atherosclerosis (n=1), and stroke of other determined etiology (n=1). On Kaplan-Meier analysis patients with structural heart disease (P=0.003), AF recurrence after the final CA (P=0.01), prior stroke (P=0.002), CHADS2score ≥2 (P=0.0002), left ventricular ejection fraction <50% (P<0.0001), and spontaneous echo contrast on transesophageal echocardiogram (P=0.0004) had a significantly higher risk of late-phase TE. Multivariate analysis indicated that CHADS2score ≥2 (HR, 4.49; 95% CI: 1.08-22.56; P=0.04) independently predicted late-phase TE. CONCLUSIONS: The incidence of TE was low after CA for paroxysmal AF, but CHADS2score ≥2 independently increased the risk of late-phase TE.

Surgical Excision of a Left Atrial Mobile Stalked Calcification Arising After Multiple Radiofrequency Ablations.

We report a rare case of a mobile ectopic calcification in the left atrium requiring surgical excision 9 years after multiple atrial fibrillation ablations. (Level of Difficulty: Intermediate.).

Symptomatic periesophageal vagal nerve injury by different energy sources during atrial fibrillation ablation.

Background: Symptomatic gastric hypomotility (SGH) is a rare but major complication of atrial fibrillation (AF) ablation, but data on this are scarce. Objective: We compared the clinical course of SGH occurring with different energy sources. Methods: This multicenter study retrospectively collected the characteristics and clinical outcomes of patients with SGH after AF ablation. Results: The data of 93 patients (67.0 ± 11.2 years, 68 men, 52 paroxysmal AF) with SGH after AF ablation were collected from 23 cardiovascular centers. Left atrial (LA) ablation sets included pulmonary vein isolation (PVI) alone, a PVI plus a roof-line, and an LA posterior wall isolation in 42 (45.2%), 11 (11.8%), and 40 (43.0%) patients, respectively. LA ablation was performed by radiofrequency ablation, cryoballoon ablation, or both in 38 (40.8%), 38 (40.8%), and 17 (18.3%) patients, respectively. SGH diagnoses were confirmed at 2 (1-4) days post-procedure, and 28 (30.1%) patients required re-hospitalizations. Fasting was required in 81 (92.0%) patients for 4 (2.5-5) days; the total hospitalization duration was 11 [7-19.8] days. After conservative treatment, symptoms disappeared in 22.3% of patients at 1 month, 48.9% at 2 months, 57.6% at 3 months, 84.6% at 6 months, and 89.7% at 12 months, however, one patient required surgery after radiofrequency ablation. Symptoms persisted for >1-year post-procedure in 7 patients. The outcomes were similar regardless of the energy source and LA lesion set. Conclusions: The clinical course of SGH was similar regardless of the energy source. The diagnosis was often delayed, and most recovered within 6 months, yet could persist for over 1 year in 10%.

Individualized left anterior oblique projection based on pigtail catheter visualization facilitates leadless pacemaker implantation.

BACKGROUND: Pacemaker positioning on the right ventricular (RV) septum during implantation is conventionally conducted utilizing two fixed fluoroscopy angles, a 45° left anterior oblique (LAO) and 35° right anterior oblique projection. However, placement location can be suboptimal, especially for leadless pacemakers (LPMs). OBJECTIVE: To evaluate the safety and ease of LPM implantation using individualized LAO projection. METHODS: Consecutive patients undergoing LPM implantation were prospectively included. The angle of the RV septum was recorded for each patient by studying the angle at which an RV pigtail catheter (RV-PC) could be seen edge on. This was then used as the preferred LAO projection angle for that patient. We evaluated the success rate and safety of this method. We also compared the RV septum angle as measured by this method versus that measured by chest CT. RESULTS: Of the 31 patients (mean age 80.6 ± 7.0 years, 15 females), LPM implantation was successful in 30. The pacemaker was implanted on the RV septum in 29 and on the free wall in one. LPM implantation was abandoned for anatomical reasons in one. Complications were limited to a groin arteriovenous fistula and one deep vein thrombosis. The angle of RV septum as measured by pigtail catheter and chest CT was not significantly different (CT: 54.8 ± 6.0°, RV pigtail catheter: 52.9 ± 6.1°, P = .07). CONCLUSIONS: Using an RV-PC to determine the preferred angle of LAO projection facilitates differentiation between the RV septum and free wall, which in turn facilitates optimal LPM placement.

High-Resolution Mapping and Ablation of Atrial Tachycardias Involving the Lateral Left Atrium.

Background The lateral left atrium (LA) is often associated with atrial tachycardia (AT) because of its complex anatomy. We sought to characterize ATs associated with the lateral LA, including the posterolateral mitral isthmus (MI) and left atrial ridge. Methods and Results Twenty-eight lateral LA-associated ATs were mapped with high-resolution mapping systems and entrainment pacing. The vein of Marshall was mapped with a 1.8-Fr mapping catheter when possible. ATs were associated with the posterolateral MI in 18 ATs (14 perimitral, 3 small reentry, and 1 focal AT). All patients had undergone MI area ablation, and all ATs were successfully eliminated. During 27.0 (interquartile range, 10.5-40.0) months of follow-up, all were free from any atrial tachyarrhythmias, with 3 patients on antiarrhythmics. Of 10 ATs involving the ridge or Marshall bundle, 3 were ridge related, 3 were Marshall bundle related based on vein of Marshall mapping, and 1 was a persistent left superior vena cava related AT. All 7 patients had undergone MI linear ablation. The critical isthmus was in the LA-ridge junction or the LA-Marshall bundle junction. Bidirectional conduction block between the LA and ridge or Marshall bundle was created. Two patients had the critical isthmus in the other area. The remaining patient had micro-reentry in the ridge. All 10 ATs were terminated during ablation at the critical isthmus. During 12.0 (5.2-31.7) months of follow-up, all were free from any atrial tachyarrhythmias, with 7 patients on antiarrhythmics. Conclusions Most ATs occurred after MI area ablation. An high resolution mapping-guided approach is highly effective for identifying the mechanism.