Citations

Introduction: Prior cardiac surgery, especially the presence of coronary bypass grafts, is thought to preclude percutaneous epicardial access (EpiAcc) and, due to limited catheter maneuverability, mapping and ablation. The objective of our study was to evaluate the feasibility and safety of EpiAcc in patients with prior cardiac surgery. Methods: We retrospectively analyzed all patients who underwent EpiAcc as part of an ablation procedure between 01/01/2004-06/30/2013 at Mayo Clinic, Rochester, MN. All had documented VT or recurring, symptomatic PVCs. Baseline clinical characteristics and procedural characteristics were collected. Results: Of 162 patients that underwent EpiAcc, 18 had prior cardiac surgery (mean age 61 years, all male). This included 10 CABG, 2 epicardial ICD placement, 5 valve surgery (3 aortic valve, 2 mitral valve), 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 patients (66.7%); the inferior approach was utilized in 78%. Of patients with prior CABG, successful access was attained in 6 (60%). The average procedural time was 441.6 ± 141.3 minutes. Adhesiolysis was required in 10 patients with the sheath, access wire, pigtail catheter or ablation catheter. Intra-procedural coronary angiography was performed in 8 patients. There were a total of 45 VTs/PVCs ablated in 18 patients (average 2.5 ± 1.7), mean cycle length 463.6 ± 95.9ms. Ultimately, 12 patients (66.7%) underwent endocardial only ablation, 1 (5.5%) had epicardial only ablation while 5 (27.8%) had endocardial/epicardial ablation. The procedure was deemed successful in 13 patients (72.2%). Four patients had bleeding complications (pericardial effusion, pericardial hematoma, hemoperitoneum and pericardial tamponade [the latter required repair of the RV wall]). In patients with coronary grafts, there was no evidence of acute graft disruption. Conclusions: Percutaneous epicardial access is feasible in patients with previous cardiac surgery, including CABG. However, adhesiolysis is frequently required. Although the risk of coronary graft injury is low, life-threatening complications may occur.

Introduction: Right ventricular apical (RVA) pacing appears to have detrimental effects on cardiac function and long term outcomes. Right ventricular non-apical (RVNA) pacing, especially in the septal position, has been postulated as an alternative that may lead to less morbidity and mortality. Prior studies have shown conflicting results and been limited by small numbers and short follow-up. We aimed to determine if right ventricular septal lead position was associated with a reduction in long-term mortality compared to RVA lead position. Methods: Patients who underwent dual-chamber pacemaker implantation from 2004 through 2013 were evaluated for right ventricular lead position based on chest radiographs. Lead positions were divided in to apical or non-apical. Non-apical lead positions were subdivided to isolate a septal lead position group. Mortality was compared between these groups. Results: During the study period, 3456 patients underwent dual-chamber pacemaker placement and had images appropriate for lead position evaluation. The group was 53.5% male with a mean age of 74 ± 13 years. RVNA lead position was found in 976 (28.2%) patients, including 243 (7.0%) with a septal position. There was no significant difference in age or prior heart failure diagnosis between groups. Kaplan-Meier survival analysis did not reveal a significant difference in mortality between patients with RVA versus RVNA lead position during 5 year follow-up (p = 0.82). However, septal lead position was associated with a significantly lower mortality compared with RVA position (p = 0.03) (figure). Conclusions: Right ventricular septal lead position is associated with a lower long-term mortality than RVA lead position. This has substantial implications regarding the preferred site for ventricular pacing lead placement.

AbstractIntroductionCardiac 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 resultsAll 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).ConclusionsSeptal 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.

Direct Pulmonary Vein Ablation With Stenosis Prevention TherapyIntroductionThe 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.MethodsIn 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.ResultsAll 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.ConclusionOur chronic canine data suggest that direct PV tissue ablation without subsequent stenosis is feasible with the use of postablation DCBs.

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.

BackgroundThis 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.MethodsAll 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.ResultsAmong 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.ConclusionsWith precise procedural planning and cardiac imaging, percutaneous epicardial access is feasible even in patients with significant anatomical challenges.

Renal Vein Stimulation Increases Blood PressureBackgroundNeurocardiogenic syncope (NCS) is a common and sometimes debilitating disorder, with no consistently effective treatment. NCS is due to a combination of bradycardia and vasodilation leading to syncope. Although pacemaker devices have been tried in treating the bradycardic aspect of NCS, no device‐based therapy exists to treat the coexistent vasodilation that occurs. The renal sympathetic innervation has been the target of denervation to treat hypertension. We hypothesized that stimulation of the renal sympathetic nerves can increase blood pressure and counteract vasodilation in NCS.Methods and ResultsHigh‐frequency stimulation (800–900 pps, 10 V, 30–200 seconds) was performed using a quadripolar catheter in the renal vein of 7 dogs and 1 baboon. A significant increase in blood pressure (BP; mean [SD] systolic BP 117 [±28] vs. 128 [±33], diastolic BP 75 [±19] vs. 87 [±29] mmHg) was noted during the stimulation, which returned to baseline after cessation of stimulation. The mean increase in systolic and diastolic BP was 13.0 (±3.3) (P = 0.006) and 10.2 (±4.6) (P = 0.08), respectively.ConclusionWe report the first ever study of feasibility and safety of high‐frequency electrical stimulation of the renal sympathetic innervation to increase BP in animal models. This has potential applications in the treatment of hypotensive states such as NCS.

Mitral Valve Injury with Catheter AblationIntroductionAn increasing number of catheter ablations involve the mitral annular region and valve apparatus, increasing the risk of catheter interaction with the mitral valve (MV) complex. We review our experience with catheter ablation‐related MV injury resulting in severe mitral regurgitation (MR) to delineate mechanisms of injury and outcomes.MethodsWe searched the Mayo Clinic MV surgical database over a 19‐year period (1993–2012) and the electrophysiologic procedures database over a 23‐year period (1990–2013) and identified 9 patients with catheter ablation related MV injury requiring clinical intervention.ResultsIndications for ablation included atrial fibrillation (AF) [n = 4], ventricular tachycardia (VT) [n = 3], and left‐sided accessory pathways [n = 2]. In all 4 AF patients, a circular mapping catheter entrapped in the MV apparatus was responsible for severe MR. In all 3 VT patients, radiofrequency energy delivery led to direct injury to the MV apparatus. In the 2 patients with accessory pathways, both mechanisms were involved (1 per patient). Six patients required surgical intervention (5 MV repair, 1 catheter removal). One patient developed severe functional MR upon successful endovascular catheter disentanglement that improved spontaneously. Two VT patients with persistent severe postablation MR were managed nonsurgically, 1 of whom died 3 months postprocedure.ConclusionCircular mapping catheter entrapment and ablation at the mitral annulus are the most common etiologies of MV injury during catheter ablation. Close surveillance of the MV is needed during such procedures and early surgical repair is important for successful salvage if significant injury occurs.

ECG Lead I and Outflow Tract ArrhythmiaIntroductionOutflow tract ventricular arrhythmia (OTVA) can be complicated to target for ablation when originating from either the periaortic or pulmonary valve (PV) region. Both sites may present with a small R wave in lead V1. However, the utility of lead I in distinguishing these arrhythmia locations is unknown.Methods and ResultsThirty‐six consecutive patients (mean age 41 ± 14 years, 13 male) underwent catheter ablation for OTVA. OTVA origin was determined from intracardiac electrogram tracings and electroanatomic maps. Observers blinded to results measured QRS waveform amplitude and duration from standard 12‐lead ECG tracings. Measurements with highest diagnostic performance were modeled into an algorithm. Sites of successful ablation were anterior right ventricular outflow tract (RVOT; n = 6), posterior RVOT (n = 4), PV (n = 18), and right coronary cusp (RCC; n = 8). Highest performing surface ECG discriminators were from lead I to V1 vectors: RCC, lead I R wave ≥ 1.5 mV, and V1 R wave ≥2.0 mV (sensitivity 87%, specificity 93%); PV, V1 R wave > 0 mV, and lead I R/(R+S) ≤ 0.75 (sensitivity 78%, specificity 72%); anterior RVOT, V1 R wave = 0 mV, and lead I R/(R+S) <0.4 (sensitivity 67%, specificity 97%); posterior RVOT, V1 R wave > 0 mV, and lead I R/(R+S) > 0.75 (sensitivity 75%, specificity 84%). Sequential algorithmic application of these criteria resulted in an overall accuracy of 72% in predicting site of OTVA origin.ConclusionsA relatively large R wave in lead I is seen with RCC origin but not PV origin. A sequential algorithm has limited but potentially significant value beyond assessment of lead I in approaching OTVA.