Friedman, Paul A.

Background Survivors of ventricular fibrillation out of hospital cardiac arrest ( VF ‐ OHCA ) due to a potentially reversible cause such as acute myocardial infarction (MI) or ischemia are considered to be at low risk of recurrent arrhythmia. Implantable cardioverter defibrillators ( ICD ) are not routinely recommended in such patients. However, the outcome of these patients in the era of rapid coronary revascularization and ICD therapy is not known. Methods and Results We examined the outcome of 114 consecutive survivors of VF OHCA due to acute MI or ischemia in Olmsted County, MN from 1990 to 2011. An ICD was implanted in 45/114 patients. ICD recipients had lower EF [median ( IQR ) 38 (26 to 54) versus 48 (35 to 58) %, P =0.04]. During a median ( IQR ) follow‐up of 9.9 (4.4 to 14.6) years, ICD implantation was associated with reduced cardiac mortality ( HR 0.24 [0.07 to 0.88], P =0.031) and a trend towards reduced all‐cause mortality ( HR 0.56 [0.30 to 1.02], P =0.059) after adjusting for the first principal component. One or more appropriate ICD therapies were delivered in 19/45, with half of the patients receiving therapy within 1 year. Patients with EF ≤35% at discharge continued to be at long‐term risk for ICD therapy compared with those with EF >35% who were at increased risk predominantly in the first 8 months. EF and revascularization were not significantly associated with ICD therapy in the multivariable analysis. Conclusions Patients with VF ‐ OHCA in the setting of acute MI or myocardial ischemia remain at high risk of recurrent ventricular arrhythmias, particularly if EF ≤35%. This suggests that ICD implantation may be reasonable if EF ≤35%.

ObjectivesTo determine the frequency and predictors of pericardial effusion following epicardial sheath removal.BackgroundPericardial effusion can occur following cardiac surgical or interventional procedures including percutaneous epicardial access (EpiAcc), which is increasingly used as part of electrophysiology ablation procedures.MethodsA retrospective analysis of the Mayo Clinic comprehensive electronic medical record was performed from all patients who underwent planned EpiAcc as part of an electrophysiology ablation procedure between January 1, 2004 and June 30, 2013.ResultsOf 144 patients (mean age 51.3 ± 15.5 years, 68% male) who underwent planned EpiAcc as part of an electrophysiology ablation (95.8% pericardial access success rate), seven (4.9%) developed a postoperative pericardial effusion requiring repeat EpiAcc. Inferior access was utilized in 74 (51.4%) patients. Patients with pericardial effusion tended to be younger (41.1 years vs 51.8 years, P = 0.08) and were more likely to have undergone inferior approach access (85.7% vs 49.6%, P = 0.06) than those who did not develop postoperative pericardial effusion. Seventy‐one percent of patients with postoperative pericardial effusion versus 32.1% of patients without postoperative pericardial effusion had a preprocedure ejection fraction ≥55% (P = 0.03). There were no procedural‐related deaths, and no difference in mortality between groups.ConclusionsPostoperative pericardial effusion requiring repeat access/drainage was relatively infrequent, occurring in 4.9% of patients shortly after epicardial procedures. While the majority occur early and therefore require close observation, some patients may present in a delayed manner.

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.

Background— Prompt recognition of underlying cardiovascular implantable electronic device (CIED) infection in patients presenting with Staphylococcus aureus bacteremia (SAB) is critical for optimal management of these cases. The goal of this study was to identify clinical predictors of CIED infection in patients presenting with SAB and no signs of pocket infection. Methods and Results— All cases of SAB in CIED recipients at Mayo Clinic from 2001 to 2011 were retrospectively reviewed. We identified 131 patients with CIED who presented with SAB and had no clinical signs of device pocket infection. Forty-five (34%) of these patients had underlying CIED infection based on clinical or echocardiographic criteria. The presence of a permanent pacemaker rather than an implantable cardioverter-defibrillator (odds ratio, 3.90; 95% confidence interval, 1.65–9.23; P =0.002), >1 device-related procedure (odds ratio, 3.30; 95% confidence interval, 1.23–8.86; P =0.018), and duration of SAB ≥4 days (odds ratio, 5.54; 95% confidence interval, 3.32–13.23; P <0.001) were independently associated with an increased risk of CIED infection in a multivariable model. The area under the receiver operating characteristics curve for the multivariable model was 0.79, indicating a good discriminatory capacity to distinguish SAB patients with and without CIED infection. Conclusions— Among patients presenting with SAB and no signs of pocket infection, the risk of underlying CIED infection can be calculated based on the type of device, number of device-related procedures, and duration of SAB. We propose that patients without any of these high-risk features have a low risk of underlying CIED infection and may be monitored closely without immediate device extraction. Prospective studies are needed to validate this risk prediction model.

Arrhythmogenic Substrate of Ventricular Arrhythmias at the AMCIntroductionCatheter ablation of ventricular arrhythmia (VA) at the fibrous aortic mitral continuity (AMC) has been described, yet the nature of the arrhythmogenic substrate remains unknown.MethodsProcedural records of 528 consecutive patients undergoing ablation of VA at Mayo Clinic, Rochester, MN, were reviewed. The electrocardiographic and electrophysiologic characteristics of patients with successful ablation at the AMC were analyzed to characterize the underlying arrhythmogenic substrate.ResultsOf the 21 patients (mean age 53.2 ± 13.4 years, 47.6% male) who underwent ablation of VA at the AMC with acute success, prepotentials (PPs) were found at the ablation sites preceding the ventricular electrogram (VEGM) during arrhythmias in 13 (61.9%) patients and during sinus rhythm in 7 (53.8%) patients. VAs with PPs were associated with a significantly higher burden of premature ventricular complexes (PVCs; 26.1 ± 10.9% vs. 14.9 ± 10.1%, P = 0.03), shorter VEGM to QRS intervals (9.0 ± 28.5 milliseconds vs. 33.1 ± 8.8 milliseconds, P = 0.03), lower pace map scores (8.7 ± 1.6 vs. 11.4 ± 0.8, P = 0.001), and a trend toward shorter V‐H intervals during VA (32.1 ± 38.6 milliseconds vs. 76.3 ± 11.1 milliseconds, P = 0.06) as compared to those without PP. A strong and positive correlation was found between V‐H interval and QRS duration during arrhythmia in those with PPs (B = 2.11, R2 = 0.97, t = 13.7, P < 0.001) but not in those without PPs.ConclusionLocal EGM characteristics and relative activation time of the His bundle suggest the possibility of conduction tissue as the origin for VA arising from the fibrous AMC. Specific identification and targeting of PPs when ablating VAs at this location may improve procedural success.

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.