The utility of a novel mapping algorithm utilizing vectors and global pattern of propagation for scar-related atrial tachycardias.

BACKGROUND: Activation maps of scar-related atrial tachycardias (AT) can be challenging to interpret due to difficulty in inaccurate annotation of electrograms, and an arbitrarily predefined mapping window. A novel mapping software integrating vector data and applying an algorithmic solution taking into consideration global activation pattern has been recently described (Coherent™, Biosense Webster "Investigational"). OBJECTIVE: We aimed to assess the investigational algorithm to determine the mechanism of AT compared with the standard algorithm. METHODS: This study included patients who underwent ablation of scar-related AT using the Carto 3 and the standard activation algorithm. The mapping data were analyzed retrospectively using the investigational algorithm, and the mechanisms were evaluated by two independent electrophysiologists. RESULTS: A total of 77 scar-related AT activation maps were analyzed (89.6% left atrium, median tachycardia cycle length of 273 ms). Of those, 67 cases with a confirmed mechanism of arrhythmia were used to compare the activation software. The actual mechanism of the arrhythmia was more likely to be identified with the investigational algorithm (67.2% vs. 44.8%, p = .009). In five patients with dual-loop circuits, 3/5 (60%) were correctly identified by the investigational algorithm compared to 0/5 (0%) with the standard software. The reduced atrial voltage was prone to lead to less capable identification of mechanism (p for trend: .05). The investigational algorithm showed higher inter-reviewer agreement (Cohen's kappa .62 vs. .47). CONCLUSIONS: In patients with scar-related ATs, activation mapping algorithms integrating vector data and "best-fit" propagation solution may help in identifying the mechanism and the successful site of termination.

Recurrent Atrial Fibrillation After Initial Long-Term Ablation Success: Electrophysiological Findings and Outcomes of Repeat Ablation Procedures.

BACKGROUND: Atrial fibrillation recurrence after initial long-term success of catheter ablation has been described, yet not well studied. We assessed the electrophysiological findings and outcomes of repeat ablation procedures in this setting. METHODS AND RESULTS: Between 2000 and 2015, 10 378 patients underwent atrial fibrillation ablation and were enrolled in a prospectively maintained data registry. From this registry, we included all 137 consecutive patients who had initial long-term success, defined as freedom from recurrent arrhythmia for >36 months off antiarrhythmics, then underwent repeat ablation for recurrent atrial fibrillation. The median arrhythmia-free period that defined long-term success was 52 months (41-68 months). In redo ablations, reconnection along at least one of the pulmonary veins (PVs) was found in 111 (81%) patients. Reconnection along a left superior, left inferior, right superior, and right inferior PV was found in 64%, 62%, 50%, and 54% of patients, respectively, and were reisolated. Additional non-PV ablations were performed in 127 (92.7%) patients: posterior wall (46%), septal to right PVs (49%), superior vena cava (35%), roof lines (52%), and cavotricuspid isthmus (33%). After a median follow-up of 17 months (5-36.9 months), 103 patients (75%) were arrhythmia free (79 off antiarrhythmics, 24 on antiarrhythmics). CONCLUSIONS: PV reconnection is the most common electrophysiological finding in patients with atrial fibrillation recurrence after long-term success, but with lower rates than what had been reported for early recurrences. In our experience, repeat ablations in this setting involve complex ablation approaches to reisolate the PVs and modify the atrial substrate and are associated with good success rates.

Evolving strategies to prevent stroke and thromboembolism in nonvalvular atrial fibrillation.

Stroke prevention in patients with nonvalvular atrial fibrillation relies on an assessment of the individual risks for stroke and bleeding. Patients at high risk for stroke are candidates for anticoagulant therapy. Anticoagulants, however, have substantial bleeding risks that must be weighed in the therapeutic decision. Warfarin has been the traditional choice, but the recently introduced novel oral anticoagulants offer similar efficacy with less bleeding risk. Additionally, they do not require monitoring and have fewer drug interactions and dietary restrictions than warfarin. Several devices, which isolate the left atrial appendage, have become available as treatment options for patients with elevated risks of both thromboembolism and bleeding complications.

Characteristics, treatment, and outcomes of periprocedural cerebrovascular accidents during electrophysiologic procedures.

OBJECTIVES: We sought to identify the characteristics, treatment, and outcomes of periprocedural cerebrovascular accident (PCVA) during electrophysiologic (EP) procedures. BACKGROUND: Periprocedural cerebrovascular accident is one of the most feared complications during EP procedures with very few data regarding its characteristics, management, and outcomes. METHODS: Between January 1998 and December 2008, we reviewed 30,032 invasive EP procedures for PCVA occurrence and characteristics. Management and outcomes were also determined. RESULTS: Thirty-eight CVAs were identified. Twenty (53 %) were intraprocedural and 18 (47 %) postprocedural. Thirty-two (84 %) were classified as strokes and six (16 %) as transient ischemic attacks. All CVAs except one (37, 97 %) were ischemic and the vast majority occurred during ablation procedures (36, 95 %). Among the 31 patients with ischemic stroke, 11 (35 %) were treated with reperfusion (eight catheter-based therapy and three intravenous t-PA) of whom five (46 %) had complete recovery, three (27 %) had partial recovery, and three (27 %) had no recovery. No hemorrhagic transformations occurred. CONCLUSION: Periprocedural cerebrovascular accident during EP procedures is rare and is almost always ischemic. It occurs more frequently during ablation procedures. Reperfusion therapy is feasible and safe.

Electrophysiologic characteristics and catheter ablation of ventricular tachyarrhythmias among patients with heart failure on ventricular assist device support.

BACKGROUND: Ventricular tachyarrhythmias (VT) are common among ventricular assist device (VAD) recipients, yet electrophysiologic (EP) characteristics and catheter ablation outcomes remain uncharacterized. OBJECTIVE: To evaluate the EP characteristics and catheter ablation outcomes for VTs among heart failure patients on VAD support. METHODS: The Cleveland Clinic registry of consecutive patients undergoing VAD placement in 1991-2010 with medically refractory, symptomatic VT referred for EP study and catheter ablation. RESULTS: Among 611 recipients of VAD (mean age 53.3 ± 12.4 years, 80% men), 21 patients (3.4%) were referred for 32 EP procedures, including 11 patients (52%) presenting with implantable cardioverter-defibrillator therapy (13 shocks, 26 antitachycardia pacing). Data from 44 inducible tachycardias (mean cycle length 339 ± 59 ms) demonstrated monomorphic VT (n = 40, 91%; superior axis 52%, right bundle branch block morphology 41%) and polymorphic ventricular tachycardia (PMVT)/ventricular fibrillation (n = 4, 8%). Electroanatomic mapping of 28 tachycardias in 20 patients demonstrated reentrant VT related to intrinsic scar (n = 21 of 28, 75%) more commonly than the apical inflow cannulation site (n = 4 of 28, 14%), focal/microreentry VT (n = 2 of 28, 7%), or bundle branch reentry (n = 1 of 28, 3.5%). Catheter ablation succeeded in 18 of 21 patients (86%). VT recurred in 7 of 21 patients (33%) at a mean of 133 ± 98 days, and 6 patients (29%) required repeat procedures, with subsequent recurrence in 4 of 21 patients (19%). CONCLUSIONS: Catheter ablation of VT is effective among recipients of VAD. Intrinsic myocardial scar, rather than the apical device cannulation site, appears to be the dominant substrate.

Role of the CHADS2 score in the evaluation of thromboembolic risk in patients with atrial fibrillation undergoing transesophageal echocardiography before pulmonary vein isolation.

OBJECTIVES: The goals of this study were to determine: 1) if low-risk patients assessed by a CHADS(2) score, a clinical scoring system quantifying a risk of stroke in patients with atrial fibrillation (AF), require a routine screening transesophageal echocardiogram (TEE) before pulmonary vein isolation (PVI); and 2) the relationship of a CHADS(2) score with left atrial (LA)/left atrial appendage (LAA) spontaneous echo contrast, sludge, and thrombus. BACKGROUND: There is no clear consensus of whether a screening TEE before catheter ablation of AF should be performed in every patient. METHODS: Initial TEEs for pre-PVI of 1,058 AF patients (age 57 +/- 11 years, 80% men) were reviewed and compared with a CHADS(2) score. RESULTS: CHADS(2) scores of 0, 1, 2, 3, 4, 5, and 6 were present in 47%, 33%, 14%, 5%, 1%, 0.3%, and 0% of patients, respectively. The prevalence of LA/LAA thrombus, sludge, and spontaneous echo contrast were present in 0.6%, 1.5%, and 35%. The prevalence of LA/LAA thrombus/sludge increased with ascending CHADS(2) score (scores 0 [0%], 1 [2%], 2 [5%], 3 [9%], and 4 to 6 [11%], p < 0.01). No patient with a CHADS(2) score of 0 had LA/LAA sludge/thrombus. In a multivariate model, history of congestive heart failure and left ventricular ejection fraction <35% were significantly associated with sludge/thrombus. CONCLUSIONS: The prevalence of LA/LAA sludge/thrombus in patients with AF undergoing a pre-PVI screening TEE is very low (<2%) and increases significantly with higher CHADS(2) scores. This suggests that a screening TEE before PVI should be performed in patients with a CHADS(2) score of >or=1, and in patients with a CHADS(2) score of 0 when the AF is persistent and therapeutic anticoagulation has not been maintained for 4 weeks before the procedure.

Remote magnetic navigation: human experience in pulmonary vein ablation.

OBJECTIVES: We aimed at assessing the feasibility and efficacy of remote magnetic navigation (MN) and ablation in patients with atrial fibrillation (AF). BACKGROUND: This novel MN system could facilitate standardization of the procedures, reducing the importance of the operator skill. METHODS: After becoming familiar with the system in 48 previous patients, 45 consecutive patients with AF were considered for ablation using the Niobe II remote magnetic system (Stereotaxis, St. Louis, Missouri) in a stepwise approach: circumferential pulmonary vein ablation (CPVA), pulmonary vein antrum isolation (PVAI), and, if failed, PVAI using the conventional approach. Remote navigation was done using the coordinate or the wand approach. Ablation end point was electrical disconnection of the pulmonary veins (PVs). RESULTS: Using the coordinate approach, the target location was reached in only 60% of the sites, whereas by using the wand approach 100% of the sites could be reached. After step 2 ablation, only 1 PV in 4 patients (8%) could be electrically isolated. Charring on the ablation catheter tip was seen in 15 (33%) of the cases. In 23 patients, all PVs were isolated with the conventional thermocool catheter, and in 22 patients only the right PVs were isolated with the conventional catheter. After a mean follow-up period of 11 +/- 2 months, recurrence was seen in 5 patients (22%) with complete PVAI and in 20 patients (90%) with incomplete PVAI. CONCLUSIONS: Remote navigation using a magnetic system is a feasible technique. With the present catheter technology, effective lesions cannot be achieved in most cases. This appears to impact the cure rate of AF patients.

Endoscopic fiberoptic assessment of balloon occlusion of the pulmonary vein ostium in humans: comparison with phased-array intracardiac echocardiography.

BACKGROUND: Anatomic pulmonary vein (PV) variants may affect the ability to position balloon catheter systems at the left atrium (LA)-PV junction with complete circumferential contact, resulting in ineffective PV isolation. OBJECTIVES: This feasibility study was performed to assess the use of the fiberoptic endoscopic light ring balloon catheter (ELRBC) in accessing the PVs and achieving adequate contact at the LA-PV junction, as visualized by phased-array intracardiac echocardiography (ICE). METHODS: We enrolled five men (mean age 59 +/- 8 years) with drug-refractory atrial fibrillation. The ELRBC consisted of a 25-mm balloon catheter with an integral endoscope contained within the balloon and a custom deflectable sheath. At the end of conventional PV isolation, the ELRBC was inserted into the LA in an attempt to position the balloon at each PV ostium. The real position of the ELRBC at this level was assessed by ICE in all patients. RESULTS: All but two PVs (right inferior PVs) (89%) were accessed with the ELRBC in a mean time of 17 +/- 3 minutes, and complete circumferential contact was visualized with the fiberoptic endoscopic component in 15 of 16 PVs accessed (94%). Contact was also confirmed by the absence of color Doppler flow through the balloon-occluded PV, as seen on ICE. On two occasions a gap was seen with the fiberoptic endoscope and visualized by the ICE only after optimization of the echo window. No complications were observed. CONCLUSIONS: The ELRBC is able to access the PV without complications. The endoscope and ICE were complementary for positioning of the balloon at the LA-PV junction and for the definition of circumferential contact.

Short- and long-term success of substrate-based mapping and ablation of ventricular tachycardia in arrhythmogenic right ventricular dysplasia.

BACKGROUND: Multiple morphologies, hemodynamic instability, or noninducibility may limit ventricular tachycardia (VT) ablation in patients with arrhythmogenic right ventricular dysplasia (ARVD). Substrate-based mapping and ablation may overcome these limitations. We report the results and success of substrate-based VT ablation in ARVD. METHODS AND RESULTS: Twenty-two patients with ARVD were studied. Traditional mapping for VT was limited because of multiple/changing VT morphologies (n=14), nonsustained VT (n=10), or hemodynamic intolerance (n=5). Sinus rhythm CARTO mapping was performed to define areas of "scar" (<0.5 mV) and "abnormal" myocardium (0.5 to 1.5 mV). Ablation was performed in "abnormal" regions, targeting sites with good pace maps compared with the induced VT(s). Linear lesions were created in these areas to (1) connect the scar/abnormal region to a valve continuity or other scar or (2) encircle the scar/abnormal region. Eighteen patients had implanted cardioverter defibrillators, 15 had implanted cardioverter defibrillator therapies, and 7 had sustained VT (6 with syncope). VTs (3+/-2 per patient) were induced (cycle length, 339+/-94 ms), and scar was identified in all patients. Scar areas were related to the tricuspid annulus, proximal right ventricular outflow tract, and anterior/inferior-apical walls. Lesions connected abnormal regions to the annulus (n=12) or other scars (n=4) and/or encircled abnormal regions (n=13). Per patient, a mean of 38+/-22 radiofrequency lesions was applied. Short-term success was achieved in 18 patients (82%). VT recurred in 23%, 27%, and 47% of patients after 1, 2, and 3 years' follow-up, respectively. CONCLUSIONS: Substrate-based ablation of VT in ARVD can achieve a good short-term success rate. However, recurrences become increasingly common during long-term follow-up.