Friedman, Paul A

AbstractIntroductionThe extravascular implantable cardioverter‐defibrillator (EV ICD) system with substernal lead placement is a novel nontransvenous alternative to current commercially available ICD systems. The EV ICD provides defibrillation and pacing therapies without the potential long‐term complications of endovascular lead placement but requires a new procedure for implantation with a safety profile under evaluation.MethodsThis paper summarizes the development of the EV ICD, including the preclinical and clinical evaluations that have contributed to the system and procedural refinements to date.ResultsExtensive preclinical research evaluations and four human clinical studies with >140 combined acute and chronic implants have enabled the development and refinement of the EV ICD system, currently in worldwide pivotal study.ConclusionThe EV ICD may represent a clinically valuable solution in protecting patients from sudden cardiac death while avoiding the long‐term consequences of transvenous hardware. The EV ICD offers advantages over transvenous and subcutaneous systems by avoiding placement in the heart and vasculature; relative to subcutaneous systems, EV ICD requires less energy for defibrillation, enabling a smaller device, and provides pacing features such as antitachycardia and asystole pacing in a single system.

AbstractBackgroundData regarding ventricular tachycardia (VT) or premature ventricular complex (PVC) ablation following mitral valve surgery (MVS) is limited. Catheter ablation (CA) can be challenging given perivalvular substrate in the setting of mitral annuloplasty or prosthetic valves.ObjectiveTo investigate the characteristics, safety, and outcomes of radiofrequency CA in patients with prior MVS and ventricular arrhythmias (VA).MethodsWe identified consecutive patients with prior MVS who underwent CA for VT or PVC between January 2013 and December 2018. We investigated the mechanism of arrhythmia, ablation approach, peri‐operative complications, and outcomes.ResultsIn our cohort, 31 patients (77% men, mean age 62.3 ± 10.8 years, left ventricular ejection fraction 39.2 ± 13.9%) with prior MVS underwent CA (16 VT; 15 PVC). Access to the left ventricle was via transseptal approach in 17 patients, and a retrograde aortic approach was used in 13 patients. A combined transseptal and retrograde aortic approach was used in one patient, and a percutaneous epicardial approach was combined with trans‐septal approach in one patient. Heterogenous scar regions were present in 94% of VT patients and scar‐related reentry was the dominant mechanism of VT. Forty‐seven percent of PVC patients had abnormal substrate at the site targeted for ablation. Clinical VA substrates involved the peri‐mitral area in six patients with VT and five patients with PVC ablation. No procedure‐related complications were reported. The overall recurrence‐free rate at 1‐year was 72.2%; 67% in the VT group and 78% in the PVC group. No arrhythmia‐related death was documented on long‐term follow‐up.ConclusionCA of VAs can be performed safely and effectively in patients with MVS.

AbstractBackgroundWhile ventricular tachycardia (VT) in the setting of postmyocardial infarction left ventricular aneurysms (LVA) is not uncommonly encountered, there is a scarcity of data regarding the safety, efficacy, and outcomes of ablation of VT in this subset of patients.MethodsOur study included consecutive patients aged 18 years or older with postmyocardial infarction LVA who presented to Mayo Clinic for catheter ablation of VT between 2002 and 2018.ResultsOf 34 patients, the mean age was 70.4 ± 9.1 years; 91% were male. Mean LVEF was 29 ± 9.7% and left ventricular end‐diastolic dimension was 64.9 ± 6.6 mm. The site of the LVA was apical in 21 patients (62%). Fifteen patients (44%) presented with electrical storm or incessant VT. Nine patients (26%) had a history of intracardiac thrombus. All except for one patient had at least one VT originating from the aneurysm. The mean number of VTs was 2.9 ± 1.7. All patients underwent ablation at the site of the aneurysm. Ablation outside the aneurysm was performed in 13 patients (38%). Low‐voltage fractionated potentials and/or late potentials at the aneurysmal site were present in all cases. Complete elimination of all VTs was achieved in 18 (53%), while the elimination of the clinical VT with continued inducibility of nonclinical VTs was achieved in a further 11 patients (32%). Two patients developed cardiac tamponade requiring pericardiocentesis. During a mean follow‐up period of 2.3 ± 2.4 years, 11 patients (32%) experienced VT recurrence. Freedom from all‐cause mortality at 1‐year follow‐up was 94%.ConclusionRadiofrequency catheter ablation targeting the aneurysmal site is a feasible and reasonably effective management strategy for clinical VTs in patients with postinfarction LVA.

AbstractBackgroundTransvenous implantable cardioverter defibrillators (TV ICD) provide life‐saving therapy for millions of patients worldwide. However, they are susceptible to several potential short‐ and long‐ term complications including cardiac perforation and pneumothorax, lead dislodgement, venous obstruction, and infection. The extravascular ICD system's novel design and substernal implant approach avoids the risks associated with TV ICDs while still providing pacing features and similar generator size to TV ICDs.Study DesignThe EV ICD pivotal study is a prospective, multicenter, single‐arm, nonrandomized, premarket clinical study designed to examine the safety and acute efficacy of the system. This study will enroll up to 400 patients with a Class I or IIa indication for implantation of an ICD. Implanted subjects will be followed up to approximately 3.5 years, depending on when the patient is enrolled.ObjectiveThe clinical trial is designed to demonstrate safety and effectiveness of the EV ICD system in human use. The safety endpoint is freedom from major complications, while the efficacy endpoint is defibrillation success. Both endpoints will be assessed against prespecified criteria. Additionally, this study will evaluate antitachycardia pacing performance, electrical performance, extracardiac pacing sensation, asystole pacing, appropriate and inappropriate shocks, as well as a summary of adverse events.ConclusionThe EV ICD pivotal study is designed to provide clear evidence addressing the safety and efficacy performance of the EV ICD System.

AbstractBackgroundPulmonary vein isolation (PVI) with autonomic modulation may be more successful than PVI alone for atrial fibrillation (AF) ablation and may be signaled by changes in sinus rhythm heart rate (HR) post ablation. We sought to determine if a change in sinus rhythm HR predicted AF recurrence post PVI.MethodsPatients who underwent AF ablation from 2000 to 2011 were included if sinus rhythm was noted on ECG within 90 days pre and 7 days post ablation. Basic ECG interval and HR changes were analyzed and outcomes determined.ResultsA total of 1152 patients were identified (74.3% male, mean age 57 ± 11 years). Mean AF duration was 5.2 ± 5.3 years. Paroxysmal AF was noted in 712 (61.8%) of the patients. Mean EF was 61% ± 6%. Sinus rhythm HR was 61 ± 11 pre‐ablation and 76 ± 13 bpm post‐ablation (27% ± 24% increase, p < .001). The ability of relative HR change post‐ablation to predict AF recurrence was borderline (hazard ratio 0.65 [0.41–1.01], p = .067). With patients separated into quartiles based on the relative HR change, the upper quartile with the largest relative increase in HR had a significantly lower rate of AF recurrence compared to the lowest quartile following multi variable modeling (p = .038). There were significant changes in PR (171 ± 28 to 167 ± 30 ms) and QTc (424 ± 25 to 434 ± 29 ms) intervals (both p < .001) but these were not predictive of outcome.ConclusionRelative changes in HR post AF ablation correlates with AF recurrence. Further prospective studies are needed to confirm this relationship.

AbstractBackgroundThe subcutaneous implantable cardioverter‐defibrillator (S‐ICD) has a larger generator and its implantation involves more dissection and tunneling compared to traditional transvenous defibrillator system. Liposomal bupivacaine, an extended‐release bupivacaine with 72 h of duration has been used for postoperative pain management in patients undergoing S‐ICD implantation. Our aim was to compare postoperative pain and opioid prescription patterns among patients undergoing S‐ICD implantation who received intraprocedural liposomal bupivacaine and those who did not.MethodsWe performed a retrospective analysis of all patients who underwent subcutaneous ICD implantation from January 1, 2013 to March 30, 2018 at the Mayo Clinic in Rochester, Minnesota. Patients were categorized into those who received liposomal bupivacaine and those who did not. Data on inpatient pain score, outpatient opioid prescription rates at discharge, and doses based on oral morphine equivalents (OME) were collected.ResultsA total of 104 patients underwent S‐ICD implantation. Intraprocedural liposomal bupivacaine was used in 69% of patients. Patients who received intraprocedural liposomal bupivacaine had similar mean inpatient pain scores (2.9 vs. 2.9, p = .786). There was also no difference in the rate of inpatient opioid administration (79.2% vs. 87.5%, p = .4139), outpatient opioid prescription (23.6% vs. 12.5%, p = .29), or mean OME (41.7‐mg vs. 16.6‐mg, p = .188) when comparing patients those who received intraprocedural liposomal bupivacaine and those who did not.ConclusionIntraprocedural liposomal bupivacaine administration was not associated with any significant impact on postoperative pain scores, inpatient opioid administration, and outpatient opioid prescription rates or OME amounts at discharge.

AbstractBackgroundMagnetic resonance imaging (MRI) in patients with legacy cardiovascular implantable electronic devices (CIEDs) in situ is likely underutilized. We hypothesized the clinical benefit of MRI would outweigh the risks in legacy CIED patients.MethodsThis is a single‐center retrospective study that evaluated and classified the utility of MRI using a prospectively maintained database. The outcomes were classified as aiding in diagnosis, treatment, or both for the patients attributable to the MRI. We then assessed the incidence of adverse effects (AE) when the MRI was performed.ResultsIn 668, MRIs performed on 479 patients, only 13 (1.9%) MRIs did not aid in the diagnosis or treatment of the patient. Power‐on reset events without clinical sequelae in three scans (0.45%) were the only AE. The probability of an adverse event happening without any benefit from the MRI scan was 1.1 × 10−4. A maximum benefit in diagnosis using MRI was obtained in ruling out space‐occupying lesions (121/185 scans, 65.4%). Scans performed in patients for elucidating answers to queries in treatment were most frequently done for disease staging at long term follow‐up (167/470 scans, 35.5%). Conservative treatment (184/470 scans, 39%) followed by medication changes (153/470 scans, 28.7%) were the most common treatment decisions made.ConclusionsThe utility of MRI in patients with non‐MRI‐conditional CIEDs far outweighs the risk of adverse events when imaging is done in the context of a multidisciplinary program that oversees patient safety.

AbstractObjectiveThis study sought to determine if single‐chamber operation and/or loss of rate response (RR) during elective replacement indicator (ERI) in patients with dual‐chamber pacemakers lead to increased symptom burden, healthcare utilization, and atrial fibrillation (AF).BackgroundDual‐chamber pacemakers often change from dual‐ to single‐chamber pacing mode and/or lose RR functionality at ERI to preserve battery. Single‐chamber pacing increases the incidence of heart failure, AF, and pacemaker syndrome suggesting these changes may be deleterious.MethodsA retrospective analysis of 700 patients was completed. Three comparisons were analyzed: Comparison 1: mode change and RR loss versus no change; Comparison 2: RR loss only versus no change; Comparison 3: mode change only versus no change (in patients with no RR programmed at baseline).ResultsIn Comparison 1, 121 (46%) patients with setting changes experienced symptoms (most often dyspnea and fatigue/exercise intolerance) versus 3 (4%) without setting changes (p < .0001). Similar results were noted in Comparisons 2 and 3 (p = .0016 and p = .0001, respectively). In Comparison 1, patients with setting change sought provider contact more than patients without setting changes (p = .0001). A significant difference was not noted in Comparison 2 or 3. Overall 14 (2%) patients were hospitalized, all of whom had setting changes.ConclusionsSetting changes at ERI including a change from dual‐ to single‐chamber pacing and/or loss of RR results in a significantly increased symptom burden and increased healthcare utilization.

AbstractIntroductionThe ablation of outflow tract premature ventricular contractions (PVCs) is generally safe and effective. In some patients, successful ablation sites may not correlate with the earliest activation. We sought to evaluate mechanistic and anatomic relevance of the region below the left sinus of Valsalva in variable morphology outflow tract ventricular arrhythmias.MethodsPVC cases where ablation was in the region inferior to the left sinus of Valsalva were identified. Procedural and demographic information and long‐term outcomes were obtained. Cadaver dissections to evaluate regional anatomy were done as well.ResultsA total of 51 cases were included (age 53 ± 10; 37 [73%] males). Ablation was done for high PVC burden (>20%; mean 27% ± 8%) and presence of symptoms (73%) or ejection fraction less than 50% (78%). QRS morphology included either R wave (8; 16%), Rs (9; 18%), or rS (67%) in lead I, no precordial transition (40; 78%), V2 transition, (7; 14%), or V3 transition (4; 8%). In 31 (61%), the site just below the left coronary cusp was the earliest site, while the remainder had another site earlier. Ablation was acutely successful in 50 of 51 (98%). After 3 months, success was noted in 48 of 51 (94%). In two patients, repeat ablation in the same region resulted in durable suppression.ConclusionThe cases presented emphasize the importance of a region centered below the left sinus of Valsalva, where multivariable morphology QRS may be successfully ablated. Consideration of mapping and ablation even when signals are late in this region may be warranted in previously failed ablation attempts or first‐line evaluation.

AbstractBackgroundInappropriate sinus tachycardia (IST) remains a clinical challenge because patients often are highly symptomatic and not responsive to medical therapy.ObjectiveTo study the safety and efficacy of stellate ganglion (SG) block and cardiac sympathetic denervation (CSD) in patients with IST.MethodsTwelve consecutive patients who had drug‐refractory IST (10 women) were studied. According to a prospectively initiated protocol, five patients underwent an electrophysiologic study before and after SG block (electrophysiology study group). The subsequent seven patients had ambulatory Holter monitoring before and after SG block (ambulatory group). All patients underwent SG block on the right side first, and then on the left side. Selected patients who had heart rate reduction ≥15 beats per minute (bpm) were recommended to consider CSD.ResultsThe mean (SD) baseline heart rate (HR) was 106 (21) bpm. The HR significantly decreased to 93 (20) bpm (P = .02) at 10 minutes after right SG block and remained significantly slower at 97(19) bpm at 60 minutes. Left SG block reduced HR from 99 (21) to 87(16) bpm (P = .02) at 60 minutes. SG block had no significant effect on blood pressure or HR response to isoproterenol or exercise (all P > .05). Five patients underwent right (n = 4) or bilateral (n = 1) CSD. The clinical outcomes were heterogeneous: one patient had complete and two had partial symptomatic relief, and two did not have improvement.ConclusionSG blockade modestly reduces resting HR but has no significant effect on HR during exercise. Permanent CSD may have a modest role in alleviating symptoms in selected patients with IST.