Radiofrequency needle for transseptal puncture is associated with lower incidence of thromboembolism during catheter ablation of atrial fibrillation: propensity score-matched analysis.

Atrial fibrillation (AF) ablation requires transseptal puncture to access the left atrium. Recently, a radiofrequency (RF) needle was developed. The purpose of this study was to compare the incidence of MRI-confirmed acute cerebral embolism (ACE) during AF ablation procedures performed with RF needle versus mechanical needle transseptal puncture. This study consisted of 383 consecutive patients who underwent catheter ablation for AF that required transseptal puncture with mechanical or radiofrequency transseptal needles. Of those, 232 propensity score-matched patients (116 with each needle type) were included in the analysis. All patients had cerebral MRI performed 1 or 2 days after the procedure. Baseline characteristics were similar between the two groups. Total procedure time was significantly shorter in Group RF than Group non-RF (167 ± 50 vs. 181 ± 52 min, P = 0.01). ACE was detected by MRI in 59 (25%) patients. All patients with ACE were asymptomatic. Incidence of ACE was lower in Group RF than Group non-RF (19 vs. 32%, P = 0.02). B-type natriuretic peptide level was higher in the patients with ACE as compared to those without ACE (65.2 ± 68.7 vs. 44.7 ± 55.1 pg/ml, P = 0.02). In multivariable analysis, the use of RF needle and BNP level was related to the incidence of ACE (OR = 0.499, 95% CI 0.270-0.922, P = 0.03 and OR = 1.005, 95% CI 1.000-1.010, P = 0.03). Use of RF needle for transseptal puncture was associated with lower total procedure time and risk of ACE during catheter ablation of AF.

Atrial fibrillation diagnosed by a medical checkup is associated with a poor outcome of catheter ablation.

Atrial fibrillation (AF), especially asymptomatic cases, is often detected by medical checkups. We investigated the outcome of AF ablation in cases detected by medical checkups. We reviewed the data of 735 patients with AF (56 ± 10 years, paroxysmal: 441 patients) who underwent initial catheter ablation. All patients were divided into two groups based on their AF being diagnosed either by a medical checkup (group M) or not (group NM). AF was diagnosed by medical checkups in 263 (36%) patients. In Group M, the age was younger, time from the diagnosis to ablation shorter, left atrium dimension larger, and left ventricular ejection fraction lower than in Group NM. Male gender, persistent AF, and asymptomatic AF were more frequently seen in Group M than in Group NM. A mean of 13 ± 11 months after the initial ablation procedure, AF recurrence was more frequently observed in group M compared to group NM (P = 0.018). While the AF recurrence rate was similar in both groups in persistent AF patients (P = 0.87), it was more frequently observed in Group M than in Group NM in paroxysmal AF patients (P = 0.005). AF diagnosed by medical checkups was often associated with a worse outcome of catheter ablation, especially in paroxysmal AF patients.

Spiral activation of the superior vena cava: The utility of ultra-high-resolution mapping for caval isolation.

BACKGROUND: Little is known about the manner in which the superior vena cava (SVC) is activated during sinus rhythm. OBJECTIVE: The purpose of this study was to assess the manner of caval activation with an ultra-high-density mapping system (Rhythmia, Boston Scientific, Marlborough, MA) and its utility for SVC isolation. METHODS: Forty patients with atrial fibrillation (mean age 55 ± 12 years; paroxysmal atrial fibrillation in 23[58%]) who underwent SVC mapping with Rhythmia were studied. The location of the sinus node (SN), phrenic nerve (PN), and the manner of caval activation during sinus rhythm were analyzed. The SVC was isolated by radiofrequency applications at electrical connections, shown as breakthroughs on the Rhythmia map. RESULTS: The SN location varied widely (lateral/posterior/anterior 60%/8%/32%), while the PN was mostly located in the lateral segment (lateral/anterior 82%/18%). In 36 patients who underwent SVC isolation, the mean number of breakthroughs was 2.5 ± 0.8. The first breakthrough predominantly located in the anterior aspect (anterior/septal/posterior/lateral 78%/14%/5%/3%), and atrial activation was conducted superiorly and clockwise from the SN (referred to as spiral activation) in 32 patients (89%). The mean rotation angle from the SN to the first breakthrough was 79° ± 41°. In addition, 10 patients (25%) showed the SN within the SVC. Although radiofrequency applications were needed at the PN capture site in 11 patients (31%) the SVC was successfully isolated without any complications in all patients. CONCLUSION: The SN location showed great heterogeneity; however, atrial activation predominantly showed a clockwise spiral form. This is the first report to use ultra-high-resolution mapping to demonstrate the manner of spiral activation, which is useful for the safe and efficient isolation of the SVC.

Pulmonary vein re-mapping after cryoballoon ablation for atrial fibrillation.

Aims: Establishment of pulmonary vein isolation (PVI) during cryoballoon (CB) ablation is generally confirmed by use of an octapolar inner-lumen mapping catheter (Achieve®). The aim of this study is to evaluate the residual PV potential (PVP) using the conventional circular catheter after CB-PVI. Methods and results: A total of 105 consecutive patients (418 PVs) with paroxysmal AF who underwent the initial CB-PVI were prospectively included in this study. Of those, 305 (73%) PVs with real-time recordings of PVP elimination by Achieve® catheter during successful PVI were included. After isolation of all 4 PVs, PV antral remapping by conventional circular mapping catheter was performed. After CB-PVI, residual PVP was detected in 4.3% (13/305) of PVs (1.2% of left-superior PV, 2.5% of left-inferior PV, none of right-superior PV, and 20% of right-inferior PV). Almost 60% of residual PV potential was located around the bottom portion of the right-inferior PV. In PVs with residual potential, PV trunk was shorter (12.7 ± 5.7 mm vs. 18.7 ± 7.9, P = 0.001), minimal balloon temperature was higher (-46.6 ± 5.9 °C vs. -50.9 ± 8.2, P = 0.02), and balloon warming time was shorter (35.6 ± 17.8 s vs. 50.0 ± 22.8, P = 0.006) than those without. All residual potentials were eliminated by additional touch up ablation. After the initial ablation procedure, 1-year AF-free rate was 79.5%. Conclusion: PV remapping after CB-PVI revealed residual antral PVP in 4.3% of PVs and in 20% of RIPVs in particular. The Achieve® catheter sometimes fails to detect complete PV antral isolation.

Significance of Inducible Nonsustained Ventricular Tachycardias After Catheter Ablation for Ventricular Tachycardia in Ischemic Cardiomyopathy.

BACKGROUND: Noninducibility of sustained monomorphic ventricular tachycardia (SMVT) postablation does not insure absence of later recurrence in patients with ischemic cardiomyopathy. This study aims to determine the relation between inducible nonsustained VT postablation and VT recurrences. METHODS AND RESULTS: One hundred sixty-five consecutive patients (156 male; age 68±9 years) underwent ablation for SMVT because of ischemic cardiomyopathy; 44 patients who did not have induction testing or in whom only ventricular fibrillation was induced after ablation were excluded. In 38 patients (23%), SMVT was inducible (group C). Of the 83 patients without inducible SMVT after ablation, nonsustained VT defined as ≥5 beats lasting for <30 s, was induced in 34 patients (group B, 21%), whereas the remaining 49 patients had no VT induced by the induction test (group A, 30%). Over a median follow-up of 18.7 months, freedom from recurrent VT at 24 months was 60% in group A, 45% in group B (P=0.017 versus group A), and 38% in group C (P=0.005 versus group A). In patients without inducible SMVT, inducible nonsustained VT and left ventricular ejection fraction was independently associated with VT recurrence (hazard ratio, 3.66 and 1.07; 95% CI, 1.3-11.1 and 1.01-1.14). CONCLUSIONS: Inducible nonsustained VT postablation suggests the continued presence of functional arrhythmia substrate. Further trials are needed to assess whether additional ablation would improve outcome in this group.

Effect of air removal with extracorporeal balloon inflation on incidence of asymptomatic cerebral embolism during cryoballoon ablation of atrial fibrillation.

BACKGROUND: Asymptomatic cerebral embolism (ACE) is sometimes detected after cryoballoon ablation of atrial fibrillation. The removal of air bubbles from the cryoballoon before utilization may reduce the rate of ACE. OBJECTIVE: This study aims to compare the incidence of ACE between a conventional and a novel balloon massaging method during cryoballoon ablation. METHODS: Of 175 consecutive patients undergoing initial cryoballoon ablation of paroxysmal atrial fibrillation, 60 (34.3%) patients underwent novel balloon massaging with extracorporeal balloon inflation in saline water (group N) before the cryoballoon was inserted into the body. The remaining 115 (65.7%) patients underwent conventional balloon massaging in saline water while the balloon remained folded (group C). Of those, 86 propensity score-matched patients were included. RESULTS: The baseline characteristics were similar between the 2 groups. In group N, even after balloon massaging in saline water was carefully performed, multiple air bubbles remained on the balloon surface when the cryoballoon was inflated in all cases. Postprocedural cerebral magnetic resonance imaging detected ACE in 14.0% of all patients. The incidence of ACE was significantly lower in group N than in group C (4.7% vs 23.3%; P = .01). According to multivariable analysis, the novel method was the sole factor associated with the presence of ACE (odds ratio 0.161; 95% confidence interval 0.033-0.736; P = .02). CONCLUSION: Preliminary removal of air bubbles in heparinized saline water with extracorporeal balloon inflation reduced the incidence of ACE. Since conventional balloon massaging failed to remove air bubbles completely, this novel balloon massaging method should be recommended before cryoballoon utilization.

Incidence and Factors Associated With the Occurrence of Pulmonary Vein Narrowing After Cryoballoon Ablation.

BACKGROUND: In contrast with traditional radiofrequency ablation, little is known about the influence of cryoballoon ablation on the morphology of pulmonary veins (PVs). We evaluated the influence of cryoballoon ablation on the PV dimension (PVD) and investigated the factors associated with a reduction of the PVD. METHODS AND RESULTS: Seventy-four patients who underwent cryoballoon ablation for paroxysmal atrial fibrillation were included in the present study. All subjects underwent contrast-enhanced computed tomography both before and at 3 months after the procedure. The PVD (cross-sectional area) was measured using a 3-dimensional electroanatomical mapping system. Each PV was evaluated according to the PVD reduction rate (ΔPVD), which was calculated as follows: (1-post-PVD/pre-PVD)×100 (%). Ninety-two percent of the PVs (271/296) were successfully isolated only by cryoballoon ablation; the remaining 8% of the PVs required touch-up ablation and were excluded from the analysis. Mild (25%-50%), moderate (50%-75%), and severe (≥75%) ΔPVD values were observed in 87, 14, and 3 PVs, respectively, including 1 case with severe left superior PV stenosis (ΔPVD: 94%) in a patient who required PV angioplasty. In multivariable analysis, a larger PV ostium and lower minimum freezing temperature during cryoballoon ablation were independently associated with PV narrowing (odds ratio, 1.773; P=0.01; and odds ratio, 1.137; P<0.001, respectively). CONCLUSIONS: A reduction of the PVD was often observed after cryoballoon ablation for atrial fibrillation. A larger PV ostium and lower minimum freezing temperature during cryoballoon ablation were associated with an increased risk of PVD reduction.

Impact of deep sedation on the electrophysiological behavior of pulmonary vein and non-PV firing during catheter ablation for atrial fibrillation.

PURPOSE: Catheter ablation for atrial fibrillation is performed with and without deep sedation, which could affect the arrhythmogenic activity during the procedure. We investigated the impact of sedation on electrophysiological properties in patients with AF who underwent catheter ablation. METHODS: This study consisted of 255 consecutive patients with atrial fibrillation (229 males, persistent: 105 patients) who underwent a single-catheter ablation procedure. The patients were divided into the following two groups according to the depth of sedation during the procedure: group M (mild sedation with flunitrazepam in 138 patients) and group D (deep sedation with propofol in 117 patients). Peripheral oxygen saturation was continuously monitored via pulse oximetry throughout the procedure. RESULTS: A spontaneous dissociated pulmonary vein activity after pulmonary vein isolation occurred more frequently in group M than in group D (29.1 vs 15.7%, P < 0.01). Adenosine-induced dormant pulmonary vein conduction was more frequently observed in group M than in group D (19.2 vs 13.0% P = 0.01). There were no significant differences in the incidence of non-pulmonary vein triggers between groups M and D (15.2 vs 11.1%, P = 0.53). The atrial fibrillation recurrence rate following the single procedure did not differ between the two groups (29.0 vs 26.5%, in groups M and D, P = 0.85). CONCLUSIONS: Although deep sedation reduced the incidence of a dissociated pulmonary vein activity and dormant pulmonary vein conduction following pulmonary vein isolation, it did not affect the recurrence rate for atrial fibrillation after the procedure.

Total absence of pulmonary vein potentials in a patient with paroxysmal atrial fibrillation: was it really isolated?

We herein present a case (72 years, male) with total absence of pulmonary veins (PVs) potentials at the beginning of the first procedure for paroxysmal atrial fibrillation (AF), demonstrating dormant conduction between the left atrium and all PVs revealed by adenosine triphosphate provocation with relation to the incidence of AF. He was free from atrial arrhythmias during 1 year follow-up after complete PV isolation with the elimination of multiple transient dormant conductions by circular mapping catheter guide ablation.

Adenosine testing during cryoballoon ablation and radiofrequency ablation of atrial fibrillation: A propensity score-matched analysis.

BACKGROUND: The infusion of adenosine triphosphate after radiofrequency (RF) pulmonary vein (PV) isolation (PVI), which may result in acute transient PV-atrium reconnection, can unmask dormant conduction. OBJECTIVE: The purpose of this study was to compare the incidence and characteristics of dormant conduction after cryoballoon (CB) and RF ablation of atrial fibrillation (AF). METHODS: Of 414 consecutive patients undergoing initial catheter ablation of paroxysmal AF, 246 (59%) propensity score-matched patients (123 CB-PVI and 123 RF-PVI) were included. RESULTS: Dormant conduction was less frequently observed in patients who underwent CB-PVI than in those who underwent RF-PVI (4.5% vs 12.8% of all PVs; P < .0001). The incidence of dormant conduction in each PV was lower in patients who underwent CB-PVI than in those who underwent RF-PVI in the left superior PV (P < .0001) and right superior PV (P = .001). The site of dormant conduction was mainly located around the bottom of both inferior PVs after CB-PVI. Multivariable analysis revealed that a longer time to the elimination of the PV potential (odds ratio 1.018; 95% confidence interval 1.001-1.036; P = .04) and the necessity of touch-up ablation (odds ratio 3.242; 95% confidence interval 2.761-7.111; P < .0001) were independently associated with the presence of dormant conduction after CB-PVI. After the elimination of dormant conduction by additional ablation, the AF-free rate was similar in patients with and without dormant conduction after both CB-PVI and RF-PVI (P = .28 and P = .73, respectively). CONCLUSION: The results of the propensity score-matched analysis showed that dormant PV conduction was less frequent after CB ablation than after RF ablation and was not associated with ablation outcomes.

Filling defects of the left atrial appendage on multidetector computed tomography: their disappearance following catheter ablation of atrial fibrillation and the detection of LAA thrombi by MDCT.

Filling defects of the left atrial appendage (LAA) on multidetector computed tomography (MDCT) are known to occur, not only due to LAA thrombi formation, but also due to the disturbance of blood flow in the LAA of patients with atrial fibrillation (AF). The purpose of this study was to evaluate the impact of the maintenance of sinus rhythm via ablation on the incidence of LAA filling defects on MDCT in patients with AF. A total of 459 consecutive patients were included in the present study. Prior to ablation, MDCT and transesophageal echocardiography (TEE) were performed. AF ablation was performed in patients without LAA thrombi confirmed on TEE. The LAA filling defects were evaluated on MDCT at 3 months after ablation. LAA filling defects were detected on MDCT in 51 patients (11.1 %), among whom the absence of LAA thrombi was confirmed in 42 patients using TEE. The LAA Doppler velocity in patients with LAA filling defects was lower than that of patients without filling defects (0.61 ± 0.19 vs. 0.47 ± 0.21 m/s; P < 0.0001). The sensitivity, specificity and negative predictive value of MDCT in the detection of thrombi were 100, 91 and 100 %, respectively. No LAA filling defects were observed on MDCT at 3 months after ablation in any of the patients, including the patients in whom filling defects were noted prior to the procedure. MDCT is useful for evaluating the presence of LAA thrombi and the blood flow of the LAA. The catheter ablation of AF not only suppresses AF, but also eliminates LAA filling defect on MDCT suggesting the improvement of LAA blood flow.

Characteristics of Clinical and Induced Ventricular Tachycardia Throughout Multiple Ablation Procedures.

BACKGROUND: Optimal procedure endpoints of catheter ablation for ventricular tachycardia (VT) are not defined and multiple repeat procedures are sometimes required. However, there are few studies to compare the details of repeat procedures to the initial procedure. The aim of this study is to compare the characteristics of clinical and induced VT throughout multiple procedures and clarify their relations. METHODS AND RESULTS: Of 425 consecutive patients with structural heart disease who underwent catheter VT ablation, second, third and fourth procedures were performed in 101, 23, and 5 patients, respectively. Of 227 VTs that were induced during the second procedure, 68 (30%) VTs had previously been induced at the first procedure. In multivariable analysis, identification of an exit/isthmus site (HR = 0.29, P = 0.047), early termination of VT during radiofrequency application (HR 0.11, P = 0.037) and elimination of target VT at the end of first procedure (HR = 0.43, P = 0.036) were independently associated with noninducibility of the same VT at the second procedure. Over the course of multiple procedures the mean VT cycle length gradually lengthened (381 ± 107, 413 ± 111, 460 ± 124, 507 ± 99 milliseconds in first, second, third, and fourth procedure, respectively, P < 0.001) and more induced VTs became mappable (32%, 40%, 62%, and 70% in first, second, third, and fourth procedure, respectively, P < 0.001). CONCLUSIONS: Identification and ablation of VT exit/isthmus, early termination of VT during radiofrequency application and elimination of targeted VT are associated with absence of that VT during a repeat procedure, and recurrences are then mostly due to new VTs or other VTs that were not induced at the first procedure.

Percutaneous retrieval of a radiolucent anchoring sleeve embolized in pulmonary artery during pacemaker implantation.

An 85-year-old female presented to our institution with symptomatic sick sinus syndrome. During pacemaker implantation, an anchoring sleeve in the right ventricular lead was embolized in the left pulmonary artery. Although the anchoring sleeve was radiolucent, digital subtraction angiography revealed an angiographic filling defect in the lower branch of the left pulmonary artery, and a snare catheter enabled the anchoring sleeve to be grasped and extracted.

Influence of the concomitant use of heparin on the effects of warfarin during catheter ablation for atrial fibrillation.

Warfarin is widely used to perform catheter ablation for atrial fibrillation (AF). Heparin is usually administered during this procedure to prevent thromboembolic events, while protamine is used to reduce the incidence of bleeding complications. The purpose of this study was to investigate the influence of heparin and protamine administration on the effects of warfarin and its safety. The subjects included 226 AF patients (206 males, 54.9 ± 9.1 years, paroxysmal/persistent AF: 118/108) undergoing AF ablation with the discontinuation of warfarin administration over 2 days. Heparin was administered to achieve an activated clotting time (ACT) above 300 s during the procedure. Several parameters of the coagulation status, including the prothrombin time international normalized ratio (PT-INR) and ACT values, measured immediately before and after protamine infusion were compared. The mean value of PT-INR prior to ablation was 1.9 ± 0.6. At the end of the procedure, the mean ACT and PT-INR values were 348.0 ± 52.9 and 2.9 ± 0.7, respectively. Following the infusion of 30 mg of protamine, both the ACT and PT-INR values significantly decreased, to 159.6 ± 31.0 (p < 0.0001) and 1.6 ± 0.3 (p < 0.0001), respectively. No cases of symptomatic cerebral infarction were observed, although femoral hematomas developed in 17 (7.5 %) of the patients without further consequence. The concomitant use of heparin augments the effect of warfarin. Meanwhile, protamine administration immediately reverses both the ACT and PT-INR, indicating the applicability of protamine for AF ablation in patients under the mixed administration of heparin and warfarin.

Catheter ablation of persistent atrial fibrillation in a patient with cor triatriatum sinister demonstrating a total common trunk of the pulmonary vein.

A 57-year-old male with persistent atrial fibrillation (AF) was referred for catheter ablation. Multidetector computed tomography (MDCT) revealed that a membrane divided the left atrium into two chambers, thus indicating the presence of cor triatriatum sinister. A 3D image reconstructed by MDCT showed that the accessory atrium received the left common and the right side PVs, as if it were a total common trunk, and this then flowed into the main atrium. After isolation of the pulmonary vein and posterior wall from the left atrium, AF could not be induced by any programmed pacing. The patient has remained free from AF during the 1 year of follow-up.

Paradoxical responses to pacing maneuvers differentiating atrioventricular node reentrant tachycardia and junctional tachycardia.

A 40-year-old female presented at our hospital because of heart palpitations. During an electrophysiological study, atrioventricular (AV) conduction showed dual AV nodal physiology. Three types of supraventricular tachycardia (SVT) were induced. The initiation of SVT was reproducibility dependent on a critical A-H interval prolongation. An early premature atrial contraction during SVT repeatedly advanced the immediate His potential with termination of the tachycardia, indicating AV node reentrant tachycardia (AVNRT). However, after atrial overdrive pacing during SVT without termination of the tachycardia, the first return electrogram resulted in an AHHA response, consistent with junctional tachycardia. The mechanism of paradoxical responses to pacing maneuvers differentiating AVNRT and junctional tachycardia was discussed.

Predictors of ectopic firing from the superior vena cava in patients with paroxysmal atrial fibrillation.

PURPOSE: Although catheter ablation targeting the pulmonary vein (PV) is a well-known therapy for patients with paroxysmal atrial fibrillation (PAF), ectopic firings from the superior vena cava (SVC) can initiate PAF. The purpose of this study was to investigate predictors of SVC firing. METHODS: The subjects included 336 consecutive PAF patients (278 males, age 56.1 ± 10.8 years) undergoing atrial fibrillation (AF) ablation. The appearance of SVC firing was monitored throughout the procedure using a decapolar catheter with multiple electrodes to record electrograms of the coronary sinus and SVC. In addition to PV isolation, SVC isolation was performed only in patients with documented SVC firing. RESULTS: SVC firing was observed in 43/336 (12.8 %) of the patients, among whom complete isolation of the SVC was achieved in 40/43 (93 %) patients. A lower body mass index (BMI) (22.8 ± 2.8 vs 24.1 ± 3.1 kg/m(2), p = 0.007) and higher prevalence of prior ablation procedures (58 vs 18 %, p = 0.0001) were related to the presence of SVC firing. In a multivariate analysis, a lower BMI (p = 0.012; odds ratio 0.83, 95 % CI 0.72 to 0.96) and history of prior ablation procedures (p < 0.0001; odds ratio 5.37, 95 % CI 2.71 to 10.63) were found to be independent predictors of the occurrence of SVC firing. Among 96 patients undergoing repeat ablation procedures, less PV-left atrial re-conduction was observed in patients with SVC firing than in those without (2.7 ± 1.2 vs 3.2 ± 0.8, p = 0.02). CONCLUSIONS: The presence of SVC firing in patients with PAF is associated with a history of repeat ablation procedures and lower BMI values.

Ventricular arrhythmias near the distal great cardiac vein: challenging arrhythmia for ablation.

BACKGROUND: Catheter ablation for ventricular arrhythmia (VA) near the distal great cardiac vein (GCV) is often challenging, and data are limited. METHODS AND RESULTS: Analysis was performed in 30 patients (19 men; age, 52.8±15.5 years) who underwent catheter ablation for focal VA (11 ventricular tachycardia and 19 premature contractions) with early activation in the GCV (36.7±8.0 ms pre-QRS). Angiography in 27 patients showed earliest GCV site within 5 mm of a coronary artery in 20 (74%). Ablation was performed in the GCV in 15 patients and abolished VA in 8. Ablation was attempted at adjacent non-GCV sites in 19 patients and abolished VA in 5 patients (4 from the left ventricular endocardium and 1 from the left coronary cusp); all success had VA with an initial r wave in lead I and activation ≤7 ms after the GCV (GCV-non-GCV interval). In 13 patients, percutaneous epicardial mapping was performed, but because of adjacent coronaries only 2 received radiofrequency application with VA elimination in 1. Surgical cryoablation was performed in 3 patients and abolished VA in 2. Overall acute success was achieved in 16 (53%) patients. After a median of 2.8 months, 13 patients remained free of VA. Major complications occurred in 4 patients, including coronary injury requiring stenting. CONCLUSIONS: Ablation for this arrhythmia is challenging and often limited by the adjacent coronary vessels. Success of anatomically guided endocardial ablation may be identified by a short GCV-non-GCV interval and r wave in lead I.

Correlates and prognosis of early recurrence after catheter ablation for ventricular tachycardia due to structural heart disease.

BACKGROUND: Catheter ablation for ventricular tachycardia (VT) from structural heart disease has a significant risk of recurrence, but the optimal duration for in-hospital monitoring is not defined. This study assesses the timing, correlates, and prognostic significance of early VT recurrence after ablation. METHODS AND RESULTS: Of 370 patients (313 men; aged 63.0±13.2 years) who underwent a first radiofrequency ablation for sustained monomorphic VT associated with structural heart disease from 2008 to 2012, sustained VT recurred in 81 patients (22%) within 7 days. In multivariable analysis, early recurrence was associated with New York Heart Association classification ≥III (odds ratio [OR] 1.90, 95% confidence interval [CI] 1.03-3.48; P=0.04), dilated cardiomyopathy (OR 1.93, 95% CI 1.03-3.57; P=0.04), prevalence of VT storm before the procedure (OR 2.62, 95% CI 1.48-4.65; P=0.001), a greater number of induced VTs (OR 1.24, 95% CI 1.07-1.45; P=0.006), and acute failure or no final induction test (OR 1.88, 95% CI 1.03-3.40; P=0.04). During a median of 2.5 (1.2, 4.0) years of follow-up, early VT recurrence was an independent correlates of mortality (hazard ratio 2.59, 95% CI 1.52-4.34; P=0.0005). CONCLUSIONS: Patients who have early recurrences of VT after ablation are a high risk group who may be identifiable from their clinical profile. Further study is warranted to define the optimal treatment strategies for this patient group.

Reentrant ventricular tachycardia originating from the periaortic region in the absence of overt structural heart disease.

BACKGROUND: In the absence of overt structural heart disease, most left ventricular outflow tract ventricular tachycardias (VTs) have a focal origin and are benign. We hypothesized that multiple morphologies (MMs) of inducible left ventricular outflow tract VT may indicate a scar-related VT that can mimic idiopathic VT. METHODS AND RESULTS: Of 54 consecutive patients referred for ablation of sustained outflow tract VT without overt structural heart disease, 24 had left ventricular outflow tract VT, 10 had MM VT, and 14 had a single VT (SM). The MM group were older (70.3±4.3 versus 53.9±15.9 years; P=0.004), had more hypertension (100% versus 29%; P=0.0006), and had longer PR intervals and QRS durations compared with the SM group. In contrast to the SM group, the MM group VTs had features consistent with reentry, including induction by programmed stimulation without isoproterenol, entrainment in some, and abnormal electrograms in the periaortic area. Periaortic region voltages suggested scar in the MM group, but not in the SM group. MRI in 2 MM patients was consistent with scar, but not in 10 SM patients. Longer radiofrequency applications were required in the MM group than in the SM group. At a median follow-up of 9.7 (3.0-32.0) months, recurrences tended to be more frequent in the MM group than in the SM group (70% versus 22%; P=0.07). CONCLUSIONS: VTs from small regions of periaortic scar can mimic idiopathic VT but are suggested by multiple VT morphologies and are more difficult to ablate. Whether these patients are at greater risk, as feared for other scar-related VTs, warrants further study.