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Purpose: This study aimed to assess the risk of procedure-related complications of percutaneous epicardial access (EpiAcc) for radiofrequency catheter ablation (RFA) of ventricular arrhythmias (VAs) in patients chronically treated oral anticoagulants (OACs) with warfarin compared to those not on OACs., Methods: We analyzed 205 patients (53 ± 16 years, 155 males) undergoing percutaneous EpiAcc as part of an RFA for VAs, and compared the outcome between patients chronically on OACs with warfarin (OAC group) and those without (non-OAC group)., Results: Forty-seven patients (23%) were chronically treated on OACs before their procedure. EpiAcc in patients on OAC (OAC group) was not associated with an increased risk of cardiac tamponade (11% vs. 6%, p = 0.238) compared to non-OAC group, but a higher risk of need for blood transfusion (17% vs. 6%; p = 0.013). With respect to the OAC group, the international normalized ratio (INR) on the day of the RFA was ≥ 2.0 in 9 patients (19%) and < 2.0 in the remaining 38 patients (81%). The rate of all complication and blood transfusion were similar between them (11% vs. 21%; p = 0.496, 11% vs. 18%; p = 0.600)., Conclusion: Percutaneous EpiAcc in patients on chronic OAC with warfarin did not significantly increase the risk of cardiac tamponade, but was associated with a higher risk of need for blood transfusion. EpiACC in patients with an INR > 2.0 is reasonable in experienced hands when clinical indications are strong.

Purpose: During cardiac mapping, it is critical to discriminate signals related to cardiac conduction versus those due to mechanical interaction with other cardiac structures such as valves. We sought to define characteristics that could facilitate discrimination of valve artifact from cardiac conduction signals., Methods: Patients with structurally normal heart undergoing mapping for ventricular arrhythmias arising from the vicinity of the aortic valve between January 2013 and May 2015 were included. Potentials felt to reflect aortic valve opening (occurring at the end of the QRS after the local ventricular signal) were termed A1, and those felt to reflect valve closure were termed A2., Results: A total of 24 patients had mapping in the sinuses of Valsalva, and 10 (average age 40 + 15, 60% male) were found to have additional signals (A1 and/or A2) notable during mapping. In all patients, intervals between A1 and A2 shortened after ectopic beats and lengthened after compensatory pauses. These variations in the interval matched the change in systolic duration on Doppler echocardiography. Overdrive atrial pacing was performed in four patients, which demonstrated progressive shortening of intervals between A1 and A2. Pacing always revealed local capture without affecting A1 or A2. In the one patient in whom ablation was performed in these areas, there was no effect on A1 or A2, suggesting these signals represented artifact., Conclusions: Valve-related signals in the aortic sinuses are commonly seen and can be distinguished. The interval between A1 and A2 correlated with mechanical systole and varied in a physiologically predictable manner with heart rate changes.

Introduction: Epicardial access (EpiAcc) has become an important adjunct for ventricular tachycardia (VT) or premature ventricular complex (PVC) ablation. We hypothesized that post-procedural pericarditis may lead to an increased risk of atrial fibrillation (AF), and therefore assessed the incidence and clinical impact of post-procedural AF in patients undergoing EpiAcc., Methods: We reviewed the records of all patients who underwent EpiAcc as part of an ablation procedure between January 1, 2004 and July 31, 2014 at Mayo Clinic Rochester. AF occurrence was determined by clinical documentation or electrocardiographic recordings post procedure., Results: Epicardial access was obtained in 170 pts (indication 110 VT and 60 PVC). The mean age was 53 ± 16 years and 122 (72%) were male. Seven (4.1%) patients developed AF within 7 days of the procedure, at a mean of 49 ± 18 h post procedure; it was paroxysmal in all patients with an average duration 6.0 ± 5.5 h (range 2-18). All patients spontaneously converted to sinus rhythm; but 3 needed rate control with AV nodal blockade (calcium channel blockers [n = 2] or beta blockers [n = 1]). One patient out of 60 who received intrapericardial steroids developed AF (2%), while of the 110 who did not receive steroids, 6 developed AF (5%) (p = 0.42). During average follow-up 2.3 years, there were no documented recurrences of atrial fibrillation in these patients., Conclusion: Atrial fibrillation following epicardial access is infrequent. When it occurs, it tends to be paroxysmal in nature and without severe symptoms. Administration of intrapericardial steroids did not affect the rate of AF post procedure; further studies however are needed to define their role.

Purpose: Percutaneous pericardial access (EpiAcc) assists ventricular tachycardia/premature ventricular complex (VT/PVC) ablation by permitting epicardial mapping and ablation outside the vicinity of the coronary venous system. We sought to determine whether expanding indications and growing operator experience have led to increased rates of EpiAcc., Methods: We reviewed the frequency of EpiAcc procedures performed during VT/PVC ablation between 2007 and 2014 to identify temporal trends in the procedure., Results: There were 758 patients undergoing 880 VT/PVC ablation procedures (average 95 patients per year; 110 procedures per year) during the study period. EpiAcc for ablation was utilized in 170 patients (181 procedures). The average age at the time of EpiAcc was 55 ± 16 years and 129 (76.0 %) patients were male. The rate of EpiAcc was 22.9 % in males and 15.4 % in females (P = 0.008). The absolute number of EpiAcc procedures increased from 2007 (6 procedures) to 2014 (27 procedures). Similarly, the proportion of patients undergoing EpiAcc increased from 8.6 % of procedures in 2007 to 24.5 % in 2014 (P < 0.0001). While EpiAcc use became more frequent, the rate of epicardial ablation among those who underwent EpiAcc remained stable (approximately 70 %)., Conclusions: Percutaneous pericardial access has been used with increasing frequency as part of VT/PVC ablations without an increase in the rate of epicardial ablation. This growing utilization may lay the foundation for novel epicardial strategies as new technologies emerge. The frequency of percutaneous pericardial access in VT/PVC ablation appears to be greater in males, reasons for which are undefined.

Introduction: Cardiac implantable electronic device (CIED) leads frequently develop echogenic masses. However, the nature of these masses is not well understood. In patients in whom atrial fibrillation (AF) catheter ablation is planned, there is concern that transseptal puncture may result in cerebrovascular embolism of these masses. The optimal therapeutic strategy in this setting remains undefined., Methods: We describe six patients identified over a 6-year period (2008-2014) with device lead-based masses prior to or at the time of AF ablation. We examined the anticoagulation strategy and periprocedural management based on mass identification., Results: In all six patients (age 39-73; four males), the device lead mass was found in the right atrium. The average mass size was 11 ± 1.3 mm. The majority of patients were already on anticoagulation (5/6; 83 %), and an intensified anticoagulation regimen was initiated (INR goal 3.0). In all six patients, the size of the device lead mass decreased on repeat imaging. In two sixths (33 %) patients, the lead-based mass completely resolved within 2 months. The remaining four patients had persistent lead-based masses (average follow-up of 10.9 ± 9.6 months)., Discussion: We describe a series of patients with CIED lead-based masses found at the time of ablation. These cases illustrate that lead-based masses can disappear while patients are on high-intensity anticoagulation, most compatible with a thrombotic origin. These early data will need to be assessed in larger cohorts for further validation and evaluation of safety.

Purpose: The rates of cardiovascular implantable electronic device (CIED) implantations and cardiac ablation procedures are increasing worldwide. To date, the management of CIED lead thrombi in the peri-ablation period remains undefined and key clinical management questions remained unanswered. We sought to describe the clinical course and management strategies of patients with a CIED lead thrombus detected in the peri-ablative setting., Methods: We performed a retrospective analysis of all patients who underwent a cardiac ablation procedure at Mayo Clinic Rochester from 2000 to 2014. Patients were included in our study cohort if they had documented CIED lead thrombus noted on peri-ablation imaging studies. Electronic medical records were reviewed to determine the overall management strategy, outcomes, and embolic complications in these patients., Results: Our overall cohort included 1833 patients, with 27 (1.4 %) having both cardiac ablation procedures as well as CIED lead thrombus detected on imaging. Of these 27 patients, 21 were male (77 %), and the mean age was 59.2 years. The mean duration of follow-up was 16.5 months (range 3 days-48.3 months). Anticoagulation was an effective therapeutic strategy, with 11/14 (78.6 %) patients experiencing either resolution of the thrombus or reduction in size on re-imaging. For atrial fibrillation ablation, the most common management strategy was a deferment in ablation with initiation/intensification of anticoagulation medication. For ventricular tachycardia ablations, most procedures involved a modified approach with the use of a retrograde aortic approach to access the left ventricle. No patient had any documented embolic complications., Conclusions: The incidence of lead thrombi in patients undergoing an ablation was small in our study cohort (1.4 %). Anticoagulation and deferral of ablation represented successful management strategies for atrial fibrillation ablation. For patients undergoing ventricular tachycardia ablation, a modified approach using retrograde aortic access to the ventricle was successful. In patients who are not on warfarin anticoagulation at the time of thrombus detection, we recommend initiation of this medication, with a goal INR of 2-3. For patients on warfarin at the time of thrombus detection, we recommend an intensification of anticoagulation with a goal INR of 3.0.

Background: Sinus node dysfunction requiring pacemaker implantation is commonly associated with atrial fibrillation (AF), but may not be clinically apparent until restoration of sinus rhythm with ablation or cardioversion. We sought to determine frequency, time course, and predictors for pacemaker implantation after catheter ablation, and to compare the overall rates to a matched cardioversion cohort., Methods and Results: We conducted a retrospective analysis using a large US commercial insurance database and identified 12,158 AF patients who underwent catheter ablation between January 1, 2005 and December 31, 2012. Over an average of 2.4 years of follow-up, 5.6 % of the patients underwent pacemaker implantation. Using the Cox proportional hazards models, we found that risk of risks of pacemaker implantation was associated with older age (50-64 and ≥65 versus <50 years), female gender, higher CHADS2 score (≥2 and 1 versus 0), higher Charlson index (≥2 versus 0-1), certain baseline comorbidities (conduction disorder, coronary atherosclerosis, and congestive heart failure), and the year of ablation. There was no significant difference in the risk of pacemaker implantation between ablation patients and propensity score (PS)-matched cardioversion groups (3.5 versus. 4.1 % at 1 year and 8.8 versus 8.3 % at 5 years)., Conclusion: Overall, pacemaker implantation occurs in about 1/28 patients within 1 year of catheter ablation. The overall implantation rate decreased between 2005 and 2012. Furthermore, the risk after ablation is similar to cardioversion, suggesting that patients require pacing due to a common underlying electrophysiologic substrate, rather than the ablation itself.

Purpose: The stiff left atrial (LA) syndrome is defined as pulmonary hypertension (PH) secondary to reduced LA compliance and has recently been shown to be one cause of PH after atrial fibrillation (AF) ablation. We aimed to determine the incidence of an increase in pulmonary arterial (PA) pressure post-ablation and examine the clinical and echocardiographic associations., Methods: Patients who underwent AF ablation between 1999 and 2011 were included if they had both an echocardiogram pre-ablation and 3 months post-ablation. Patients were then separated into two groups with the increased PA pressure group defined as patients with >10 mmHg increase in right ventricular systolic pressure (RVSP) post-ablation and a post-ablation RVSP >35 mmHg., Results: Of the 499 patients meeting the study criteria, 41 (8.2%) had an increase in RVSP >10 mmHg and RVSP >35 mmHg post-ablation. On echocardiogram, the two groups had similar E/A and E/e' ratios pre-ablation. However, post-ablation, the increased PA pressure group had higher E/A (2.12 vs. 1.49, p < 0.01) and E/e' (14.7 vs. 11.2, p < 0.01) ratios. LA expansion index values were lower in the increased PA pressure group pre-ablation (51 vs. 92%, p < 0.01), but not significantly different post-ablation (82 vs. 88%, p = 0.44)., Conclusions: Around 8% of patients develop an increase in estimated PA pressure after AF ablation. Echocardiographic parameters suggest that patients who develop increased PA pressure are developing (or unmasking) left ventricular diastolic dysfunction.

This is a report of the Heart Rhythm Society (HRS) Task Force on Catheter and Surgical Ablation of Atrial Fibrillation, developed in partnership with the European Heart Rhythm Association (EHRA), a registered branch of the European Society of Cardiology and the European Cardiac Arrhythmia Society (ECAS), and in collaboration with the American College of Cardiology (ACC), American Heart Association (AHA), the Asia Pacific Heart Rhythm Society (APHRS), and the Society of Thoracic Surgeons (STS). This is endorsed by the governing bodies of the ACC Foundation, the AHA, the ECAS, the EHRA, the STS, the APHRS, and the HRS.

Background: Atrial septal defects (ASD), including patent foramen ovale, have been linked to an increased prevalence of migraine headaches in the general population. A similar association with migraine is speculated for iatrogenic ASD due to atrial septal puncture during catheter ablation for atrial fibrillation (AF)., Methods: A total of 2,069 patients who underwent catheter ablation for AF at Mayo Clinic, Rochester, MN between January 2001 and December 2008 were scheduled for follow-up at least at 3 months and annually thereafter. Data were collected from the questionnaires patients answered at follow-up inquiring about presence and characteristics of any headaches following the procedure and further chart review. Definite migraine was diagnosed based on clinical features per the International Classification of Headache Disorder-II definition., Results: Twenty-two patients (1.1%) had a new-onset definite migraine, 12 (0.6%) had a new-onset probable migraine, ten (0.5%) with a previous history of migraine had worsened headaches, and four (0.2%) had headache due to an alternate identifiable cause; a total of 48 patients (2.3%) reported post-procedural headaches. Nineteen of 22 patients (86%) with definite migraine had complete resolution of symptoms at 1- to 2-year follow-up., Conclusion: New-onset migraine is an uncommon and usually temporary side effect of catheter ablation for AF. The mechanism for post-procedure headache remains unclear.

Introduction: Certain outflow tract tachyarrhythmias require ablation above the semilunar valves. Understanding of the regional anatomy of these arrhythmogenic sites is required to avoid complications., Methods and Results: We examined 603 formalin-fixed autopsy hearts from October 1998 to July 2003. Three hundred forty-two of 603 (57%) had myocardial extensions above the aortic valve, and 446 of 602 (74%) had extensions above the pulmonary valve. Extensions were noted above the aortic right coronary cusp (RCC) in 332 of 603 (55%; 2.8 ± 1.2 mm), left coronary cusp (LCC) in 145 of 603 (24%; 1.5 ± 0.5 mm), and non-coronary/posterior cusp in four of 603 (0.66%; 1.3 ± 0.5 mm; p < 0.0001), intercuspally in 295 of 603 (49%; 2.2 ± 1.1 mm) and into the cusps in 13 of 603 (2.2%). Extensions were noted above the pulmonary right cusp in 360 of 602 (60%; 4.0 ± 2.5 mm), posterior/left cusp in 313 of 602 (52%; 3.6 ± 2.1 mm), and anterior cusp in 268 of 602 (45%; 3.7 ± 2.2 mm; p < 0.0001), intercuspally in 438 of 602 (73%; 3.4 ± 1.8 mm) and into the cusps in ten of 602 (1.7%). The left main coronary artery was closer to the myocardial extensions above the nearest pulmonary valve cusp (posterior) than those above the nearest aortic valve cusp (LCC; 4.8 ± 1.7 vs. 16.3 ± 3.3 mm, p = 0.0005)., Conclusion: Myocardial extensions are common into the great arteries above the semilunar cusps and intercuspally, and rarely into the cusps themselves. The extensions are larger and more symmetric above the pulmonary cusps as compared to the aortic cusps, the most prominent aortic extensions being above the RCC. The left main coronary artery courses close to the extensions above the posterior pulmonary cusp.

Purpose: Left atrial ablation is increasingly used to treat patients with symptomatic atrial fibrillation (AF). Prior to ablation, exclusion of left atrial appendage (LAA) thrombus is important. Whether ECG-gated dual-source computed tomography (DSCT) provides a sensitive means of detecting LAA thrombus in patients undergoing percutaneous AF ablation is unknown. Thus, we sought to determine the utility of ECG-gated DSCT in detecting LAA thrombus in patients with AF., Methods: A total of 255 patients (age 58 ± 11 years, 78% male, ejection fraction 58 ± 9%) who underwent ECG-gated DSCT and transesophageal echocardiography (TEE) prior to AF ablation between February 2006 and October 2007 were included. CHADS2 score and demographic data were obtained prospectively. Gated DSCT images were independently reviewed by two cardiac imagers blinded to TEE findings. The LAA was either defined as normal (fully opacified) or abnormal (under-filled) by DSCT., Results: An under-filled LAA was identified in 33 patients (12.9%), of whom four had thrombus confirmed by TEE. All patients diagnosed with LAA thrombus using TEE also had an abnormal LAA by gated DSCT. Thus, sensitivity and specificity for gated DSCT were 100% and 88%, respectively. No cases of LAA filling defects were observed in patients <51 years old with a CHADS2 of 0., Conclusion: In patients referred for AF ablation, thrombus is uncommon in the absence of additional risk factors. Gated DSCT provides excellent sensitivity for the detection of thrombus. Thus, in AF patients with a CHADS2 of 0, gated DSCT may provide a useful stand-alone imaging modality.

Introduction: We reviewed our experience in managing intracardiac ultrasound-detected left atrial thrombus and analyzed the impact of the timing of heparin therapy on thrombus incidence., Methods and Results: We identified 508 patients undergoing ablation procedures for atrial fibrillation in which intracardiac ultrasound was used. All patients received unfractionated heparin during the procedure: 31 patients before the first transseptal puncture (preTS1), 257 between the first and second transseptal punctures (TS1-TS2), and 220 following both punctures (postTS2). By using intracardiac echocardiography (ICE), thrombus was detected in 30 of these 508 patients (5.9%). Of these, 29 were in the left atrium and constituted our study group. In 21 patients, the thrombi were successfully aspirated from the left atrium using strong suction through the transseptal sheath. All patients in whom thrombi were aspirated did well without neurological event or death. When patients received heparin therapy either preTS1 or TS1-TS2, there was a significant decrease in the occurrence of ICE-detected left atrial thrombus compared with those who received heparin postTS2 (0 of 31 patients (0%) preTS, 9 of 257 (3.5%) TS1-TS2, and 20 of 220 (9.1%) postTS2; (preTS1 vs postTS2, p = 0.01; preTS2 [preTS1 and TS1-TS2] vs postTS2, p < 0.001)., Conclusion: Early administration of intravenous heparin, specifically before transseptal puncture, decreases the incidence of left atrial thrombi.

Background: The SVC may require ablation to treat atrial fibrillation. Phrenic nerve proximity identified with pacing maneuvers may preclude ablation., Methods: We tested a new method using "cryo-mapping" to ablate despite nerve proximity., Results: Of 833 patients undergoing ablation, 110 (12%) had arrhythmogenic substrate at the SVC/RA junction. Of these 110 patients, 66 (60%) had consistent diaphragmatic stimulation when pacing at 10 mA at the prospective site of ablation. Of these 66 patients, 7 had continued arrhythmogenicity despite attempts to modify this substrate. For these 7 patients, we paced 4 cm into the SVC where consistent phrenic nerve stimulation was obtained, and cryoablation at -30 degrees C was performed at sites requiring ablation. In 6 of 7 patients (86%), with continued diaphragmatic capture, cryoablation at -70/-80 degrees C was then performed. In 1 of 7 patients (14%), diaphragmatic stimulation ceased at -30 degrees C, and energy delivery stopped. In the 6 patients in whom cryoablation was completed, the arrhythmogenic substrate was successfully ablated without phrenic nerve injury., Conclusions: A novel "cryo-mapping" technique during phrenic nerve pacing can be used to successfully ablate arrhythmogenic substrate at the SVC/RA junction despite phrenic nerve proximity.

Patients with the Marfan syndrome may pose a difficult challenge for catheter-based interventions due to frequent coexisting valve disease, potential delay in vascular healing and repair, and intra-atrial scar from prior cardiac surgery. We report a case series of four patients with Marfan or Marfan-like syndromes who underwent ablation for drug-refractory atrial fibrillation. Ultimately three of four patients remained in sinus rhythm, however most patients required multiple ablative attempts and long-term atrial flutter was common. Nonetheless, peri-procedural complications were minimal despite the connective tissue disorder and prosthetic valves in three of four patients. In conclusion, catheter ablation of AF in patients with Marfan syndrome is a viable option in those individuals refractory to conventional therapy.