Prevalence and predictors of atrial fibrillation in patients with embolic stroke of undetermined source: a real-life single-center retrospective study.

INTRODUCTION: Up to one-third of ischemic strokes remained cryptogenic despite extensive investigations. Atrial fibrillation may be detected in a significant proportion of patients with embolic stroke of undetermined source, particularly after the introduction of implantable loop recorder in clinical practice. METHODS: We retrospectively included all the consecutive patients with embolic stroke of undetermined source referred to our units in the period November 2013 to December 2018 and in which an implantable loop recorder was positioned within 6 months from stroke event. Prevalence and predictors of atrial fibrillation were investigated. RESULTS: One hundred thirty-eight patients with embolic stroke of undetermined source fulfilling inclusion criteria were identified. The crude prevalence of atrial fibrillation at the end of observation period was of 45.7%. Incidence rates at 6, 12, 18, 24, and 36 months resulted, respectively, 31.8% (95% CI, 30.4-46.7), 38.0% (95% CI, 30.4-46.9), 42.6% (95% CI, 34.5-51.6), 46.6% (95% CI, 38.2-55.8), and 50.4% (95% CI, 41.6-59.9). On multivariate analysis, only excessive supraventricular electric activity and left atrial enlargement resulted to be significant predictors of atrial fibrillation (p = 0.037 and p < 0.0001, respectively). CONCLUSIONS: Atrial fibrillation may be detected in a relevant proportion (up to 50%) of patients with embolic stroke of undetermined source if a careful and extensive diagnostic work-up is employed. Excessive supraventricular electric activity and left atrial enlargement are significant predictors of the occurrence of atrial fibrillation in these patients.

Zero-fluoroscopy atrial fibrillation ablation in the presence of a patent foramen ovale: a multicentre experience.

INTRODUCTION: Atrial fibrillation ablation has historically been guided by fluoroscopy, with the related enhanced risk deriving from radiation. Fluoroscopy exposure may be confined to guide the transseptal puncture. Small sample size study presented a new methodology to perform a totally fluoroless atrial fibrillation ablation in the case of a patent foramen ovale (PFO). We evaluated this methodology in a large sample size of patients and a multicentre experience. METHODS AND RESULTS: Two hundred and fifty paroxysmal atrial fibrillation patients referred for first atrial fibrillation ablation with a CARTO3 electroanatomic mapping system were enrolled. In 58 out of 250 patients, a PFO allowed crossing of the interatrial septum, and a completely fluoroless ablation was performed applying the new method (Group A). In the remaining patients, a standard transseptal puncture was performed (Group B). Pulmonary vein isolation was achieved in all patients with comparable procedural and clinical outcomes at short- and long-term follow-up. CONCLUSION: The presence of a PFO may allow a completely fluoroless well tolerated and effective atrial fibrillation ablation. Probing the fossa ovalis looking for the PFO during the procedure is desirable, as it is not time-consuming and can potentially be done in every patient undergoing atrial fibrillation ablation.

Tricuspid Valve Dysfunction Caused by Right Ventricular Leads.

Tricuspid regurgitation is increasingly recognized as a clinically significant valvular condition. The role of multiple pacemaker and implantable cardiac defibrillator leads in distortion of the valve structure and the risk of trauma to the valve and subvalvular apparatus with lead extraction contribute to the development of tricuspid regurgitation (TR). There is a clinical imperative to better understand the optimal way to diagnose lead-related TR, risk factors for the development of TR, and optimal strategies to mitigate this problem.

Tricuspid Valve Dysfunction Following Pacemaker or Cardioverter-Defibrillator Implantation.

The potential for cardiac implantable electronic device leads to interfere with tricuspid valve (TV) function has gained increasing recognition as having hemodynamic and clinical consequences associated with incremental morbidity and death. The diagnosis and treatment of lead-related (as distinct from functional) tricuspid regurgitation pose unique challenges. Because of pitfalls in routine diagnostic imaging, a high level of clinical suspicion must be maintained to avoid overlooking the possibility that worsening heart failure is a consequence of mechanical interference with TV leaflet mobility or coaptation and is amenable to lead extraction or valve repair or replacement. The future of cardiac implantable electronic devices includes pacing and perhaps defibrillation without a lead traversing the TV.

Right ventricular pacemaker lead position is associated with differences in long-term outcomes and complications.

INTRODUCTION: Cardiac pacing from the right ventricular apex is associated with detrimental long-term effects and nonapical pacing locations may be associated with improved outcomes. There is little data regarding complications with nonapical lead positions. The aim of this study was to assess long-term outcomes and lead-related complications associated with differing ventricular lead tip position. METHODS AND RESULTS: All adult patients who underwent dual-chamber pacemaker implantation from 2004 to 2014 were included if they had postprocedure chest radiographs amenable to lead position determination. Long-term outcomes and lead-related complication rates were recorded. These were compared at 5 years between: (1) apical and septal leads, (2) apical and nonseptal nonapical (NSNA), and (3) apical and septal with >40% ventricular pacing. We retrospectively evaluated 3,450 patients, which included 238 with a septal position and 733 with NSNA lead positions. Septal lead position was associated with a lower mortality compared to apical leads (24% vs. 31%, P = 0.02). In patients with greater than 40% pacing, septal leads were associated with significantly higher rates of incident atrial fibrillation compared to apical leads (49% vs. 34%, P = 0.04). NSNA positions were associated with a significantly higher rate of lead dislodgement (4% vs. 2%, P = 0.005) and need for revision (8% vs. 5%, P = 0.005). CONCLUSIONS: Septal pacemaker lead position is associated with a lower mortality compared to apically placed leads, but a higher incidence of atrial fibrillation with higher percentage ventricular pacing. NSNA lead locations are associated with more complications and should be avoided.

Right atrial lead fixation type and lead position are associated with significant variation in complications.

PURPOSE: Optimal atrial pacemaker lead position and fixation mechanism have not been determined with regard to effect on complications. We aimed to determine the association between atrial lead-related complications and varying atrial lead tip positions and lead fixation mechanisms. METHODS: All patients who underwent dual-chamber pacemaker implant between 2004 and 2014 were retrospectively reviewed for atrial lead tip position and fixation type. Lead-related complications were assessed by electronic medical record review. Complication rates were compared at 1 year by chi-square analysis and at 5 years using a Kaplan-Meier analysis. RESULTS: During the study period, 3451 patients (mean age 73.9, 53.4 % male) underwent dual-chamber pacemaker placement. Active fixation leads were associated with a higher incidence of pericardial effusion (81 (2.9 %) vs. 6 (1.0 %), p = 0.005) and pericardiocentesis (46 (1.6 %) vs. 2 (0.3 %), p = 0.01) at 1 year compared to passive fixation leads. There was no difference in overall complication rates by fixation type (161 (5.7 %) vs. 29 (4.6 %), p = 0.26). Low atrial septal lead tip position was associated with a higher rate of lead dislodgement (10 (15.2 %)) compared to appendage (46 (1.6 %)), free wall (10 (2.1 %)), or high atrial septal (2 (4.7 %)) positions (p < 0.001). This difference was also reflected in a significantly increased need for lead revision and overall complications. A multivariate analysis which included potential confounders confirmed the association of active fixation leads with an increased rate of perforation-related complications (p = 0.03) and septal lead location with increased rates of dislodgement (p < 0.001). CONCLUSIONS: Active compared to passive lead fixation increases the risk for pericardial effusion requiring pericardiocentesis. There is a clear association between low atrial septal lead position and lead dislodgement requiring lead revision.

Ventricular pacing - Electromechanical consequences and valvular function.

Although great strides have been made in the areas of ventricular pacing, it is still appreciated that dyssynchrony can be malignant, and that appropriately placed pacing leads may ameliorate mechanical dyssynchrony. However, the unknowns at present include: 1. The mechanisms by which ventricular pacing itself can induce dyssynchrony; 2. Whether or not various pacing locations can decrease the deleterious effects caused by ventricular pacing; 3. The impact of novel methods of pacing, such as atrioventricular septal, lead-less, and far-field surface stimulation; 4. The utility of ECG and echocardiography in predicting response to therapy and/or development of dyssynchrony in the setting of cardiac resynchronization therapy (CRT) lead placement; 5. The impact of ventricular pacing-induced dyssynchrony on valvular function, and how lead position correlates to potential improvement. This review examines the existing literature to put these issues into context, to provide a basis for understanding how electrical, mechanical, and functional aspects of the heart can be distorted with ventricular pacing. We highlight the central role of the mitral valve and its function as it relates to pacing strategies, especially in the setting of CRT. We also provide future directions for improved pacing modalities via alternative pacing sites and speculate over mechanisms on how lead position may affect the critical function of the mitral valve and thus overall efficacy of CRT.

Pulmonary embolism in patients with transvenous cardiac implantable electronic device leads.

BACKGROUND: Cardiac implantable electronic devices (CIEDs) are commonly associated with transvenous lead-related thrombi that can cause pulmonary embolism (PE). METHODS AND RESULTS: We retrospectively evaluated all patients with transvenous CIED leads implanted at Mayo Clinic Rochester between 1 January 2000, and 25 October 2010. Pulmonary embolism outcomes during follow-up were screened using diagnosis codes and confirmed with imaging study reports. Of 5646 CIED patients (age 67.3 ± 16.3 years, 64% men, mean follow-up 4.69 years) 88 developed PE (1.6%), incidence 3.32 [95% confidence interval (CI) 2.68-4.07] per 1000 person-years [men: 3.04 (95% CI 2.29-3.96) per 1000 person-years; women: 3.81 (95% CI 2.72-5.20) per 1000 person-years]. Other than transvenous CIED lead(s), 84% had another established risk factor for PE such as deep vein thrombosis (28%), recent surgery (27%), malignancy (25%), or prior history of venous thromboembolism (15%). At the time of PE, 22% had been hospitalized for ≥ 48 h, and 59% had been hospitalized in the preceding 30 days. Pulmonary embolism occurred in 22% despite being on systemic anticoagulation therapy. Out of 88 patients with PE, 45 subsequently died, mortality rate 93 (95% CI 67-123) per 1000 person-years (hazard ratio 2.0, 95% CI 1.5-2.7, P < 0.0001). CONCLUSIONS: Though lead-related thrombus is commonly seen in patients with transvenous CIED leads, clinical PE occurs with a low incidence. It is possible that embolism of lead thrombus is uncommon or emboli are too small to cause consequential pulmonary infarction.

The effect of mitral valve surgery on ventricular arrhythmia in patients with bileaflet mitral valve prolapse.

BACKGROUND: Bileaflet mitral valve prolapse (biMVP) is associated with frequent ventricular ectopy (VE) and malignant ventricular arrhythmia. We examined the effect of mitral valve (MV) surgery on VE burden in biMVP patients. METHODS: We included 32 consecutive patients undergoing MV surgery for mitral regurgitation secondary to biMVP between 1993 and 2012 at Mayo Clinic who had available pre- and post-operative Holter monitoring data. Characteristics of patients with a significant reduction in postoperative VE (group A, defined as >10% reduction in VE burden compared to baseline) were compared with the rest of study patients (group B). RESULTS: In the overall cohort, VE burden was unchanged after the surgery (41 interquartile range [16, 196] pre-surgery vs. 40 interquartile range [5186] beats/hour [bph] post-surgery; P = 0.34). However, in 17 patients (53.1%), VE burden decreased by at least 10% after the surgery. These patients (group A) were younger than the group B (59 ± 15 vs. 68 ± 7 years; P = 0.04). Other characteristics including pre- and postoperative left ventricular function and size were similar in both groups. Age <60 years was associated with a reduction in postoperative VE (odds ratio 5.8; 95% confidence interval, 1.1-44.7; P = 0.03). Furthermore, there was a graded relationship between age and odds of VE reduction with surgery (odds ratio 1.9; 95% confidence interval 1.04-4.3 per 10-year; P = 0.04). CONCLUSIONS: MV surgery does not uniformly reduce VE burden in patients with biMVP. However, those patients who do have a reduction in VE burden are younger, perhaps suggesting that early surgical intervention could modify the underlying electrophysiologic substrate.

Direct Pulmonary Vein Ablation With Stenosis Prevention Therapy.

INTRODUCTION: The dominant location of electrical triggers for initiating atrial fibrillation (AF) originates from the muscle sleeves inside pulmonary veins (PVs). Currently, radiofrequency ablation (RFA) is performed outside of the PVs to isolate, rather than directly ablate these tissues, due to the risk of intraluminal PV stenosis. METHODS: In 4 chronic canine experiments, we performed direct PV muscle sleeve RFA ± postablation drug-coated balloon (DCB) treatment with paclitaxel/everolimus. Of the 4 PVs, 2 PVs were ablated and treated with DCB, 1 PV was ablated without DCB treatment (positive control), and 1 PV was left as a negative control. Local electrograms were assessed in PVs for near-field signals and were targeted for ablation. After 12-14 weeks survival, PVs were interrogated for absence of near-field PV potentials, and each PV was assessed for stenosis. RESULTS: All canines survived the study period without cardiorespiratory complications, and remained ambulatory. In all canines, PVs that were ablated and treated with DCB remained without any significant intraluminal stenosis. In contrast, PVs that were ablated and not treated with DCB showed near or complete intraluminal stenosis. At terminal study, PV potentials remained undetectable. A blinded, histologic analysis demonstrated that ablated PVs without DCB treatment had extensive thrombus, fibrin, mineralization, and elastin disruption. CONCLUSION: Our chronic canine data suggest that direct PV tissue ablation without subsequent stenosis is feasible with the use of postablation DCBs.

Zero-Fluoroscopy Ablation of Accessory Pathways in Children and Adolescents: CARTO3 Electroanatomic Mapping Combined with RF and Cryoenergy.

BACKGROUND: Fluoroscopic catheter ablation of cardiac arrhythmias in pediatric patients exposes the patients to the potential risk of radiation considering the sensitivity of this population and its longer life expectancy. We evaluated the feasibility, safety, and efficacy of accessory pathway (AP) ablation guided by CARTO3 electroanatomic mapping (EAM) system with both cryoenergy and radiofrequency (RF) energy in order to avoid x-ray exposure in pediatric patients. METHODS: We included 44 patients (mean age: 13.1 ± 3.3 years); nine of 44 presented concealed AP. An electrophysiological study with a three-dimensional EAM reconstruction was performed in every patient with a venous transfemoral direct right atrium approach or an arterial transfemoral retrograde approach to reach the mitral annulus. In two patients with left-sided AP, the ablation was performed via a patent foramen ovale. RESULTS: A total of 47 APs were present, left sided in 45% (21/47) of cases (15 lateral, one anterior, three posteroseptal, and two posterolateral) and right sided in 55% (26/47; one anterior, three anterolateral, one posterolateral, three lateral, five para-Hisian, 12 posteroseptal, and one anteroseptal). Ablation without the use of fluoroscopy was successfully performed in every patient (33 with RF and in 11 with cryoenergy). No complication occurred. At a mean follow-up of 16.0 ± 11.7 months, we observed seven recurrences, three of them successfully re-ablated without fluoroscopy. In one case cryoablation of a para-Hisian AP was ineffective in the long term. CONCLUSIONS: Three-dimensional EAM allowed a safe and effective fluoroless AP ablation procedure in a pediatric population both with RF and cryoenergy.

Correlation of geomagnetic activity with implantable cardioverter defibrillator shocks and antitachycardia pacing.

OBJECTIVE: To investigate a potential relationship between implantable cardioverter defibrillator (ICD) therapies and daily geomagnetic activity (GMA) recorded in a large database. PATIENTS AND METHODS: The ALTITUDE database, derived from the Boston Scientific LATITUDE remote monitoring system, was retrospectively analyzed for the frequency of ICD therapies. Daily GMA was expressed as the planetary K-index and the integrated A-index and was graded as levels I (quiet), II (unsettled), III (active), and IV (storm). RESULTS: A daily mean ± SD of 59,468±11,397 patients were monitored between January 1, 2009, and May 15, 2012. The distribution of days according to GMA was as follows: level I, 924/1231 (75%); level II, 226/1231 (18%); level III, 60/1231 (5%); and level IV, 21/1231 (2%). The daily mean ± SD numbers of ICD shocks received per 1000 active patients in the database were 1.29±0.47, 1.17±0.46, 1.03±0.37, and 0.94±0.29 on level I, II, III, and IV days, respectively; the daily mean ± SD sums of shocks and antitachycardia pacing therapies were 9.29±2.86, 8.46±2.45, 7.92±1.80, and 7.83±2.28 on quiet, unsettled, active, and storm days, respectively. A significant inverse relationship between GMA and frequency of ICD therapies was identified, with the most pronounced difference between level I and level IV days (P<.001 for shocks; P=.008 for shocks + antitachycardia pacing). CONCLUSION: In a large-scale cohort analysis, ICD therapies were delivered less frequently on days of higher GMA, confirming the previous pilot data and suggesting that higher GMA does not pose an increased risk of arrhythmias using ICD therapies as a surrogate marker. Further studies are needed to gain an in-depth understanding of the underlying mechanisms.

Percutaneous epicardial access for mapping and ablation is feasible in patients with prior cardiac surgery, including coronary bypass surgery.

BACKGROUND: Prior cardiac surgery, especially the presence of coronary artery bypass grafts, is thought to preclude percutaneous epicardial access (EpiAcc) and, therefore, mapping and ablation. We evaluated the feasibility and safety of EpiAcc in patients with a prior cardiac operation. METHODS AND RESULTS: We retrospectively analyzed all patients who underwent EpiAcc for ablation for ventricular tachycardia or symptomatic premature ventricular complexes between 2004 and 2013 at Mayo Clinic, Rochester, MN. Of 162 patients who underwent EpiAcc, 18 had prior cardiac surgery (median age, 64 years, all men). This included 10 coronary artery bypass grafts, 2 epicardial implantable cardioverter defibrillator placement, 5 valve surgery, 2 septal myectomy, 1 aortic arch replacement, 1 myocardial bridge unroofing, and 1 myocardial perforation repair (3 patients had multiple procedures). Access was successful in 12 of 18; the inferior approach was used in 78%. Successful access was achieved in 6 of 10 patients with prior coronary artery bypass grafts. Adhesiolysis was required in 10 patients with the sheath, access wire, and pigtail or ablation catheter. Intraprocedural coronary angiography was performed in 8 patients. A total of 45 ventricular tachycardias/premature ventricular complexes were ablated. Thirteen patients underwent endocardial-only ablation, 2 had epicardial-only ablation, whereas 3 had endocardial-epicardial ablation. Ablation was deemed successful in 13 of 18 patients. Four patients had bleeding complications (pericardial effusion, pericardial hematoma, hemoperitoneum, and pericardial tamponade). In patients with coronary grafts, there was no evidence of acute graft disruption. CONCLUSIONS: Percutaneous EpiAcc is feasible in patients with previous cardiac surgery, including coronary artery bypass grafts. However, adhesiolysis is frequently required. Although the risk of coronary graft injury is low, life-threatening complications may occur.

Successful percutaneous epicardial access in challenging scenarios.

BACKGROUND: This case-series highlights strategies used for successful epicardial access in challenging cases. Percutaneous epicardial access has become a valuable tool for mapping and ablating arrhythmias. However, this technique can be especially difficult in certain circumstances and is frequently avoided. METHODS: All cases of epicardial access for ablation from our institution were reviewed searching for exceptionally difficult cases in patients with complex pericardial and thoracic anatomy. The successful strategies are characterized in this report. RESULTS: Among 144 patients who underwent an epicardial ablation procedure between January 2004 and June 2013, four required unconventional approaches for epicardial access for ventricular tachycardia ablation. Two patients (one with previous cardiac surgery and one with prior pericardial effusion) had substantial fibrous pericardial adhesions with no virtual pericardial space and required adhesiolysis. One patient, status postpartial colectomy, underwent computed tomography-guided intercostal epicardial access due to the presence of bowel throughout the subdiaphragmatic space in the upper abdomen. The fourth patient had partial congenital absence of the pericardium and underwent epicardial access through the creation of a subxiphoid window. All epicardial accesses were successful and performed without major complication. CONCLUSIONS: With precise procedural planning and cardiac imaging, percutaneous epicardial access is feasible even in patients with significant anatomical challenges.

Percutaneous Epicardial Pacing using a Novel Insulated Multi-electrode Lead.

INTRODUCTION: Epicardial cardiac resynchronization therapy (CRT) permits unrestricted electrode positioning. However, this requires surgical placement of device leads and the risk of unwanted phrenic nerve stimulation. We hypothesized that shielded electrodes can capture myocardium without extracardiac stimulation. METHODS: In 6 dog and 5 swine experiments, we used a percutaneous approach to access the epicardial surface of the heart, and deploy novel leads housing multiple electrodes with selective insulation. Bipolar pacing thresholds at prespecified sites were tested compare electrode threshold data both facing towards and away from the epicardial surface. RESULTS: In 151 paired electrode recordings (70 in 6 dogs; 81 in 5 swine), thresholds facing myocardium were lower than facing away (median [IQR] mA: dogs 0.9 [0.4-1.6] vs 4.6 [2.1 to >10], p<0.0001; swine 0.5 [0.2-1] vs 2.5 [0.5-6.8], p<0.0001). Myocardial capture was feasible without extracardiac stimulation at all tested sites, with mean ± SE threshold margin 3.6±0.7 mA at sites of high output extracardiac stimulation (p=0.004). CONCLUSION: Selective electrode insulation confers directional pacing to a multielectrode epicardial pacing lead. This device has the potential for a novel percutaneous epicardial resynchronization therapy that permits placement at an optimal pacing site, irrespective of the anatomy of the coronary veins or phrenic nerves.

Catheter Ablation of Atrial Fibrillation Without Radiation Exposure Using A 3D Mapping System.

Transcatheter ablation procedures have been traditionally performed under fluoroscopic guidance. However, x-ray exposure is afflicted by the risk of developing malignancies as well as other deterministic effects of radiation. For this reason, radiation doses in the interventional laboratory should be reduced "As Low As Reasonably Achievable", with respect to the safety of the patients and the medical staff. This is of utmost importance in atrial fibrillation (AF) ablations, which are usually lengthy procedures. With the improvement of technology, the development of additional imaging tools and the widespread of 3D electroanatomic mapping systems (EAM), near-zero fluoroscopy AF ablation procedure is becoming a reality, limiting fluoroscopy use mainly to guide transseptal puncture. In the present paper we reviewed the risks to health related to x-ray exposure and we discussed the current state of knowledge of catheter ablation of AF without fluoroscopy in the 3D EAM system era.

Novel balloon catheter device with pacing, ablating, electroporation, and drug-eluting capabilities for atrial fibrillation treatment--preliminary efficacy and safety studies in a canine model.

Pulmonary vein isolation is an established therapeutic procedure for symptomatic atrial fibrillation (AF). This approach involves ablation of atrial tissue just outside the pulmonary veins. However, patient outcomes are limited because of a high rate of arrhythmia recurrence. Ablation of electrically active tissue inside the pulmonary vein may improve procedural success, but is currently avoided because of the complication of postablation stenosis. An innovative device that can ablate inside pulmonary veins and prevent stenosis is a viable strategy to increase long-term efficacy. We have developed a prototypical balloon catheter device capable of nonthermal pulmonary vein ablation along with elution of an antifibrotic agent intended to eliminate arrhythmogenic substrate without the risk of stenosis and have demonstrated its functionality in 4 acute canine experiments. Further optimization of this device may provide an innovative means to simultaneously ablate and prevent pulmonary vein stenosis for improved AF treatment in humans.