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Cardiac implantable electronic devices, including implantable cardioverter-defibrillators and therapy, are part of guideline-indicated treatment for a subset of patients with heart failure with reduced ejection fraction. Current technological advancements in cardiac implantable electronic devices have allowed the detection of specific physiological parameters that are used to forecast clinical decompensation through algorithmic, multiparameter remote monitoring. Other recent emerging technologies, including cardiac contractility modulation and baroreflex activation therapy, may provide symptomatic or physiological benefits in patients without indications for cardiac resynchronization. Our goal in this state-of-the-art review is to describe the new commercially available technologies, their purported mechanisms of action, and the evidence surrounding their clinical roles, limitations and future directions. Finally, we underline the need for standardized workflow and close interdisciplinary management of this population to ensure the delivery of high-quality care.

Patients with left ventricular assist devices (LVAD) often tolerate ventricular arrhythmias (VA). We aim to assess the frequency and outcomes of ICD therapies averted by ultraconservative ICD programming (UCP) in LVAD patients.This single center, retrospective cohort study included patients with LVADs and ICDs implanted from 2015 to 2019 that had UCP. The aim for UCP was to maximally delay VA treatments and maximize anti-tachycardia pacing (ATP) prior to ICD shocks. VA events were reviewed after UCP and evaluated under prior conservative programming to assess for potentially averted events (that would have resulted in either ATP or defibrillation with prior programming).Fifty patients were included in the study with follow-up of median 16 ± 10.2 months after UCP. The median time from LVAD implantation to reprogramming was 7 days (IQR 5-9 days). Fourteen patients (28%) had potentially averted VA events that would have been treated with their prior ICD programming (82 total events, median two events per patient, IQR 1-10 events). Treated VA events occurred in 15 patients (30%). Eleven of the 14 patients with potentially averted VAs had treated events as well. Only one patient reported definitive symptoms of self-limited "dizziness" during a potentially averted event that did not result in hospitalization. No patients died of complications from or needed emergent care/hospitalization due a potentially averted VA.UCP in LVAD patients likely prevented unnecessary VA treatments in many patients with minimal reported symptoms during these potentially averted events. Prospective studies are necessary to confirm these findings.

Introduction Electromagnetic interference (EMI) from left ventricular assist devices (LVADs) can cause implantable cardioverter-defibrillator (ICD) oversensing. We sought to assess the frequency of inappropriate shocks/oversensing due to LVAD-related EMI and prospectively compare integrated (IB) versus dedicated bipolar (DB) sensing in patients with LVADs. Methods Single-center study in LVAD patients with Medtronic or Abbott ICDs between September 2017 and March 2020. We excluded patients that were pacemaker dependent. Measurements were obtained of IB and DB sensing and noise to calculate a signal-to-noise ratio (SNR). Device checks were reviewed to assess appropriate and inappropriate sensing events. Results Forty patients (age 52 ± 14 years, 75% men, 38% ischemic cardiomyopathy) were included with the median time between LVAD implantation and enrollment of 6.7 months [2.3, 11.4 months]. LVAD subtypes included: HeartWare (n=22, 55%), Heartmate II (n=10, 25%), and Heartmate III (n=8, 20%). Over a follow-up duration of 21.6 ± 12.9 months after LVAD implantation, 5% of patients (n=2) had oversensing of EMI from the LVAD (both with HeartWare LVADs and Abbott ICDs) at 4 days and 10.8 months after LVAD implantation. Both patients underwent adjustment of ventricular sensing with resolution of oversensing and no further events over 5 and 15 months of further follow-up. The SNR was similar between IB and DB sensing (50 [29-67] and 57 [41-69], p=0.89). Conclusion ICD oversensing of EMI from LVADs is infrequent and can be managed with reprogramming the sensitivity. There was no significant difference in the R-wave SNR with IB versus DB ICD leads. This article is protected by copyright. All rights reserved.

The subcutaneous ICD (S-ICD) is a viable alternative to transvenous ICD and avoids intravascular complications in patients without a pacing indication. The outcomes of S-ICD implantation are uncertain in patients with prior sternotomy.We aim to compare the implant techniques and outcomes with S-ICD implantation in patients with and without prior sternotomy.Multicenter retrospective cohort study including adult patients with an S-ICD implanted between January 2014 and June 2020. Outcomes were compared between patients with and without prior sternotomy.Among the 212 patients (49 ± 15 years old, 43% women, BMI 30 ± 8 kg/mImplantation of an S-ICD in patients with prior sternotomy is safe with a similar risk of 30-day complications and inappropriate ICD shocks as patients without prior sternotomy.

Many techniques exist for venous access (VA) during cardiac implantable electronic device (CIED) implantation.We sought to evaluate the learning curve with ultrasound (US) guided axillary vein access (USAA).Single-center prospective randomized controlled trial of patients undergoing CIED implantation. Patients were randomized in a 2:1 fashion to USAA versus conventional VA techniques. The primary outcomes were the success rates, VA times and 30-day complication rates.The study included 100 patients (age 68 ± 14 years, BMI 27 ± 4 kg/mAlthough the success rate with USAA was high, there was a significant learning curve. Once experienced with the USAA technique, there is the potential for reduced complications without adding to the procedure duration.

Background: Voltage mapping is critical to define substrate during ablation. In ventricular tachycardia, abnormal potentials may be targets. However, wavefront of activation could impact local signal characteristics. This may be particularly true when comparing sinus rhythm versus paced rhythms. We sought to determine how activation wavefront impacts electrogram characteristics. Methods: Patients with ischemic cardiomyopathy, ventricular tachycardia, and without fascicular or bundle branch block were included. Point by point mapping was done and at each point, one was obtained during an atrial paced rhythm and one during a right ventricular paced rhythm. Signals were adjudicated after ablation to define late potentials, fractionated potentials, and quantify local voltage. Areas of abnormal voltage (defined as

IntroductionLeft atrial appendage occlusion (LAAO) is recommended in patients with non-valvular atrial fibrillation (AF) who have contraindications to or are intolerant of long-term oral anticoagulants (OAC), but its impact on hospitalization rates has not been well described. The objective of our study is to describe the incidence of all-cause, bleeding-related, and thrombosis-related hospitalizations before and after LAAO.Material and methodsWe used the Nationwide Readmission Database to include patients aged ≥ 18 years with a diagnosis of AF who underwent transcatheter LAAO during the months of February-November in each year between 2016 and 2018. Patients who died during the index procedure or had missing length of hospital stay or mortality information were excluded.ResultsA total of 27,633 patients were included (median age: 77 years, 41% female) with an average pre- and post-LAAO monitoring period of 6.5 and 5.5 months respectively. Of these, 10,808 (39.1%) patients had one or more admissions prior to the procedure compared to 7,196 (26.0%) after the procedure. There was a 26% reduction in incidence of all-cause admissions (rate ratio (RR) = 0.74, 95% confidence interval (CI): 0.71–0.76; p < 0.001), 49% reduction in bleeding-related admissions (RR = 0.51, 95% CI: 0.48–0.55; p < 0.001), and 71% reduction in thrombosis-related readmissions (RR = 0.29, 95% CI: 0.26–0.33; p < 0.001) after LAAO.ConclusionsIn a contemporary, nationally representative dataset, we found that LAAO is associated with a significant decrease in all-cause, bleeding-related, and thrombosis-related admissions. These findings lend support to the current use of transcatheter LAAO in clinical practice for patients with contraindications to OAC and/or at high risk of bleeding.

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Introduction: Watchman device is an alternative for anticoagulation in atrial fibrillation (AF) patients for stroke prevention but there is paucity of data on 30-day readmission trends and factors influencing it. Methods: We queried the 2016-2017 National Readmission Database for all adult AF patients, who had procedure done in January to November and discharged alive, using ICD10 code of 02L73DK. We divided the study population into deciles and used the annual procedure volume cut-off of 20 to compare the lowest volume decile with rest of the study population. Hierarchical multivariable logistic regression model was created to identify predictors of 30-day readmission and hospitals were included as random effect. Results: A total of 4565 and 9219 procedures were included for 2016 and 2017; respectively. Overall readmission rate was 1287 (9.3%) and of these 43 (3.3%) died on readmission. The 30-day readmission rate in 2017 was 906 (9.8%) compared to 381 (8.4%) in 2016 (p = 0.053) but the mortality associated with readmission was significantly higher in 2017 at 38 (0.42%) compared to 5 (0.11%) in 2016 (p=0.01). The proportion of patients with Charlson co-morbidity index ≥5 was significantly higher in 2017 at 1177 (12.8%) compared to 384 (8.4%) in 2016 (p Conclusions: Thirty-day readmission rate and mortality has been increasing along with the procedural volume which could be related to patients with higher number of co-morbidities receiving the device. Lower procedural volume of the hospital is an independent predictor of readmission.

Introduction: There are no randomized controlled trials that compared the outcomes of leadless pacemaker (L-PPM) implantation with transvenous pacemaker (TV-PPM) and there is scarcity of data on real world outcomes. Methods: We queried National Inpatient Sample to identify all adult patients who had primary discharge diagnosis of conduction disorders or tachy-arrhythmias and excluded patients who had a concomitant procedure for valve replacement, coronary artery bypass grafting, ablation and/or cardiac implantable electronic device removal so that complications can be attributed to the pacemaker implantation. We included only procedures from November 2016 to December 2017 as Micra was the only available L-PPM during that period. For the comparison cohort we selected patients, during the same time period, who had a procedure code for single chamber pacemaker implantation in conjunction with right ventricular lead placement. We performed 1:1 propensity score matching and the variables used for matching are marked with asterisk in Table 1. All the codes used to identify complications has been previously validated from the Micra Post-approval registry and Coverage with Evidence Study. Results: Total of 1,305 patients for L-PPM and 13,905 patients in the TV-PPM group were included. Baseline characteristics with standardized mean difference before and after matching are shown in Table 1. Briefly, patients in L-PPM group were younger but had higher co-morbidities compared to TV-PPM group. The complications before and after matching are shown in Table 2. Conclusions: In conclusion, we found no significant difference between in-hospital complications after propensity score matching, with the exception of deep venous thrombosis. There was no difference between length of stay but cost for L-PPM was significantly higher. In this real-world analysis, we found that the leadless PPM implantation is safe in comparison to transvenous PPM.

Background: Preliminary reports have suggested the role of annular calcium in independently predicting pacemaker implantation after transcatheter aortic valve replacement (TAVR). Data regarding role of calcium in the aortic-valvular complex on pacemaker dependency is lacking. Hypothesis: Calcium volume and score in the aortic annular region predicts RV (right ventricle) pacing burden. Methods: We conducted a retrospective single-center study at our tertiary care center including patients who had new pacemaker implantation after TAVR procedure (n=47). Standard calcium scoring software was used to demarcate and quantify the calcium along the aortic cusps and subvalvular region and dichotomized into septal and non-septal based on proximity to the interventricular septum. Standard statistical tests were used for analysis with two-sided p-value Results: The mean age was 78.6 ± 10.3 years and females were 42.6%. At baseline, 44.7% had narrow QRS complex, with 31.9% had right bundle branch block (RBBB), 8.5% had left bundle branch block (LBBB). Median Pre-TAVR QRS duration was 112 ms. Median septal and non-septal calcium score were 646 and 474 with a volume of 441 mm 3 and 327.2 mm 3 , respectively. Patients with progression to complete heart block (CHB) during index admission had significantly higher non-septal volume (650 mm 3 vs 344 mm 3 ;p=0.01) and score (892 vs 485;p=0.01) when compared to progression after discharge. Similarly, the high burden of RV pacing (>40%) was associated with lower septal calcium score (989 vs 552, p= 0.03) and volume (717 mm 3 vs 385 mm 3 , p=0.03) within 3 months of TAVR. No septal or non-septal parameters were predictive of pacing burden for mid-term (3-12 months) and long-term (>12 months) follow up. Septal calcium parameters were not predictive of RV pacing burden or progression to CHB. Conclusion: Quantitative calcium in the non-septal and septal regions were predictive of early progression to CHB and a higher burden of RV pacing, respectively. Larger scale studies on calcium distribution and the burden should be performed to validate our findings.

Introduction: Subcutaneous ICD (S-ICD) implantation is a viable alternative to transvenous ICD implantation in patients without a pacing indication. The S-ICD lead is placed near the sternum. The safety of S-ICD implantation and risk for inappropriate shocks is uncertain in patients with prior sternotomy. Methods: This single-center retrospective cohort study included patients that had implantation of an S-ICD between February 2014 - May 2020. The 30-day complication rates and long-term risks of inappropriate shocks were compared between patients with and without prior sternotomy. Results: Ninety-eight patients (52 ± 15 years old, 43% men, BMI 29 ± 6, 72% primary prevention, 28% ischemic cardiomyopathy, median LVEF 30% (IQR 25-45%)) underwent S-ICD implantation, among whom 19 (19.4%) had a prior sternotomy. The median time between sternotomy and S-ICD implantation was 96 (IQR 4.1-306) months. The sternal coil was primarily implanted left of the sternum (n=17/19, 89%). A two-incision technique was used in 79% of patients with prior sternotomy vs. 65% without sternotomy (p=0.23). The 30-day complication rate was similar between those with and without prior sternotomy (n=1/19 vs. n=10/79, 5% vs. 13%, p=0.36). The only 30-day complication in patients with prior sternotomy was a hematoma without intervention. The 30-day complications in patients without prior sternotomy included: superficial site infection resolving with brief antibiotics (n=4), inappropriate shock (n=3), lead migration requiring revision (n=2), and a hematoma without intervention (n=1). Over a median follow-up of 17.1 (IQR 3.4-29.1) months, the frequency of inappropriate shocks was similar between patients with and without prior sternotomy (n=1/19 and n=6/79, 5% vs. 8%, p=0.72). The median time to inappropriate shock from S-ICD implantation was 1.1 (IQR 0.1-19.8) months. The mechanisms of inappropriate shocks were T-wave oversensing or other oversensing (n=5/7, 72%), air in the pocket (n=1/7, 14%), and atrial tachycardia (n=1/7, 14%). Conclusions: Implantation of S-ICD in patients with prior sternotomy was not associated with an increased risk of 30-day complications or inappropriate shocks. These outcomes need to be confirmed in larger, multicenter studies.

Introduction: The Emory risk score has been developed to predict new pacemaker implantation in patients undergoing TAVR procedures. There is limited data on assessing risk of early versus late pacemaker implantation in these patients. Hypothesis: The Emory risk score is similar for patients with both early and late pacemaker implantation in TAVR patients. Methods: A single center observational study was performed at our tertiary care center. All patients who underwent pacemaker implantation after TAVR procedures were included. Patients were categorized as early or late if they had pacemaker implantation within the same admission versus implantation post discharge. Standard statistical tests were used for analysis with two-sided p value Results: A total of 97 patients were studied between January 2017 to April 2020. The mean age was 77.5 ± 7 years and females were 41.2%. At baseline patients with early implantation of pacemakers (n=66) had a higher proportion of underlying RBBB (45.2% vs 23.3%, p=0.43), higher valve size as well as a higher incidence of valve oversizing > 146% (43.9 % vs 19.4 %, p =0.23)when compared to patients with late pacemakers(n=31). There was no difference between patient characteristics, baseline comorbidities, pre procedural ECG parameters as well as use of beta blocking agents. Late pacemaker implantations were associated with a overall lower Emory Risk score (1.06±1.41 vs 1.70±1.35, p =0.037). Conclusions: The Emory Risk score is significantly different for early and late pacemaker implantation. Further studies are needed evaluate risk of late pacemaker implantation.

Introduction: End-stage renal disease (ESRD) is associated with increased complications due to oral anticoagulation (OAC) use for stroke prevention in atrial fibrillation (AF). Left atrial appendage occlusion (LAAO) is indicated for patients who cannot tolerate or prefer not to use OAC but the outcomes of LAAO in ESRD has not been well studied. Methods: Using National Readmission Database January 2016-December 2017, we identified all adult AF patients who had LAAO performed in the months of January to November with no missing length of stay and/or mortality information. We excluded patients who had ablation, device implantation/revision, other form of LAAO and/or coronary artery bypass graft surgery performed during index hospitalization. 1:1 propensity score matching was performed for patients with and without ESRD based on variables shown in Table 1. The main outcome of interest was early mortality defined as mortality of index hospitalization or 30-day readmissions and index hospital complications. Results: A total of 13,790 procedures were included and of these 370 patients had history of ESRD. The baseline characteristics before and after matching are shown in table 1. After propensity score matching, ESRD group was associated with significantly higher early mortality, 30-day readmissions, systemic embolism and pericardial complications (Table 2). In the matched cohort, none of the patients had postprocedural cerebrovascular accident, transient ischemic attack, device thrombosis and device embolization. After propensity matching 2 (0.5%) developed acute kidney injury requiring hemodialysis. Conclusions: ESRD is associated with higher LOS, index hospital complications and early mortality from LAAO compared to patients without ESRD. Further studies comparing outcomes between OAC use and LAAO are warranted.

Background: Pulmonary vein stenosis is a dreaded complication of endocardial atrial fibrillation (AF) ablation but rare after epicardial ablation and has not been reported after epicardial left atrial appendage occlusion (LAAO). Case: A 55-year-old male was referred to our tertiary hospital for management of left superior pulmonary vein (LSPV) stenosis causing dyspnea on exertion. About 2 years prior to presentation, he underwent quadruple coronary artery bypass grafting for non-ST elevation myocardial infarction along with modified Cox-Maze procedure with pulmonary vein and posterior wall isolation as well as epicardial LAAO with AtriClip for history of paroxysmal AF. At our institute, V/Q scan showed ventilation-perfusion mismatch and absent perfusion of the left upper lobe (Figure 1A). Cardiac CT showed persistent LSPV occlusion (Figure 1B). TEE showed atrial appendage occluded with a clip and no flow was observed from LSPV (Figure 1C). After multidisciplinary discussion between cardiology and cardiothoracic surgery teams, surgical approach to remove the AtriClip was deemed futile as it was placed 2 years ago and less likely to result in resolution of stenosis. Thus, an endovascular approach was attempted with left atrial and pulmonary vein angiography showing LSPV to be 100% occluded (Figure 1D). Pulmonary vein recanalization was attempted but was not successful. Conclusion: Our case highlights the importance of recognition of PVS as a possible complication after epicardial LAAO as early intervention can improve patient outcomes. PVS has been previously described with Maze procedure but that patient was successfully treated with catheter-balloon angioplasty. Given 100% occlusion and difficulty with recanalization makes epicardial ablation a less likely cause of occlusion in our case. More careful application of Atriclip protocols might be necessary to prevent this potential complication.

Introduction: Cardiac resynchronization therapy (CRT) upgrade is indicated for improvement of cardiac function in patients with chronic right ventricular (RV) pacing burden >40% and heart failure with reduced ejection fraction. It is uncertain whether the CRT response is different among patients with high (≥90%) versus intermediate ( Hypothesis: To assess the impact of baseline RV pacing percent on ECG and echocardiographic response after CRT upgrade for pacing induced cardiomyopathy. Methods: We conducted a retrospective study of all CRT upgrades for pacing induced cardiomyopathy at our hospital from January 2017 to December 2018. Cohorts were grouped by RV pacing burden ≥90% or Results: We included 82 patients (age 74 ± 12 yr., 71% male) who underwent CRT upgrade for pacing induced cardiomyopathy. The RV pacing burden was ≥90% [median 99% (IQR 98-99%)] in 61 patients, and Conclusions: A higher baseline RV pacing burden predicts a greater improvement in LVEF after CRT upgrade for pacing induced cardiomyopathy.

Background: Hypertensive emergency (HTNE) diagnostic code was introduced, in the US, in October 2016 to improve identification of patients with end-organ damage due to high blood pressure but its impact is unclear. Objective: To assess the accuracy of HTNE code using administrative data. Methods: We used National Inpatient Sample 2017 to identify adult patients, age ≥18 years, with International Classification of Disease-10th Clinical modification (ICD-10-CM) code of I16.1. We used the presence of end-organ damage diagnostic codes to identify true HTNE. Results: A total of 194,495 patients had a diagnosis of HTNE. Of these only 144,070 (74.1%) had a concomitant diagnosis of end-organ damage. Baseline characteristics of entire cohort stratified by presence of target organ damage (Table 1A) and frequency of end-organ damage in true HTNE patients (Table 1B) are shown. Patients with true HTNE were likely to be older and male with higher co-morbidity burden. There was also significant difference in outcomes between two groups with a higher proportion of true HTNE patients experiencing longer length of stay and increased mortality which is in-line with previous studies. Conclusions: The accuracy of hypertensive emergency diagnosis code is low with positive predictive value of 74.1% and caution is advised when using with administrative data. Further studies, using individual patient discharge records, are required to validate HTNE code.

INTRODUCTION Ultrasound guided axillary vein access (UGAVA) is an emerging approach for cardiac implantable electronic device (CIED) implantation not widely utilized. METHODS AND RESULTS This is a retrospective, age and sex-matched cohort study of CIED implantation from January 2017 to July 2019 comparing UGAVA before incision to venous access obtained after incision without ultrasound (conventional). The study population included 561 patients (187 with attempted UGAVA, 68 ± 13 years old, 43% women, body mass index (BMI) 30 ± 8 kg/m2 , 15% right-sided, 43% implantable cardioverter-defibrillator, 15% upgrades). UGAVA was successful in 178/187 patients (95%). In nine patients where UGAVA was abandoned, the vein was too deep for access before incision. BMI was higher in abandoned patients than successful UGAVA (38 ± 6 vs. 28 ± 6 kg/m2 , p

Left ventricular assist devices (LVAD) are increasingly used in the management of patients with advanced heart failure. Many of these patients have or will be considered for a cardiac implantable electronic device (CIED) such as an implantable cardioverter-defibrillator or a cardiac resynchronization therapy device. Frequent interplay is often encountered due to the complexity of these devices and the underlying disease states. Proactive management strategies and an awareness of interactions may help reduce adverse events. Here we review the current literature, present management recommendations, and discuss potential future investigations for CIEDs in patients with LVADs.

BACKGROUND The safety of perioperative anticoagulation (AC) and antiplatelet (AP) therapy with subcutaneous implantable cardioverter-defibrillator (S-ICD) implantation is unknown. The purpose of this study was to identify the risk factors associated with hematoma complicating S-ICD implantation. METHODS Records were retrospectively reviewed from 200 consecutive patients undergoing S-ICD implantation at two academic medical centers. A hematoma was defined as a device site blood accumulation requiring surgical evacuation, extended hospital stay, or transfusion. RESULTS Among 200 patients undergoing S-ICD implantation (age 49 ± 17 years, 67% men), 10 patients (5%) had a hematoma, which required evacuation in six patients (3%). Warfarin was bridged or uninterrupted in 12 and 13 patients, respectively (6% and 6.5%). Four of 12 patients with warfarin and bridging AC (33%) and two of 13 patients with uninterrupted warfarin (15%) developed a hematoma. Neither of the two patients with uninterrupted DOAC had a hematoma. No patients on interrupted AC without bridging (n = 26, 13 with warfarin, 13 with DOAC) developed a hematoma. A hematoma was also more likely with the use of clopidogrel (n = 4/10 vs 10/190, 40% vs 5.3%, P

Left atrial appendage closure (LAAC) has emerged as a viable option for stroke prevention, especially in those intolerant of or not suitable for long-term oral anticoagulation therapy. This article describes the clinical characteristics, indications, and a proposed referral system for potential LAAC patients. Patient selection remains a challenge because of the paradox between the available randomized data on this intervention and the actual patient population who may gain maximum benefit. Further investigations comparing different LAAC devices with each other and with novel oral anticoagulants are needed. Also, the optimal antithrombotic regimen post-procedure has yet to be determined.

Background Premature ventricular complexes (PVCs) often originate from multiple locations. Objective The goals of this study were to assess characteristics of patients with pleomorphic, idiopathic PVCs and to determine the impact of pleomorphic PVCs on outcomes. Methods Records were collected from 153 consecutive patients referred for ablation of PVCs. Patients with structural heart disease (n = 34) or inadequate ambulatory electrocardiographic data (n = 19) were excluded. Results Among 100 consecutive patients (age 52 ± 15 years, 53% men, 31% pleomorphic vs 69% monomorphic) referred for ablation of idiopathic PVCs, the success rate was lower in patients with pleomorphic PVCs than in those with monomorphic PVCs (71% vs 90%, P = .017, overall 84%). The presence of pleomorphic PVCs was independently associated with unsuccessful ablation. A cutoff of ≥156 nonpredominant PVCs over 24 hours best differentiated successful from unsuccessful ablation procedures (area under the curve 0.64, sensitivity 56%, specificity 74%). Pleomorphic PVCs more often had an epicardial origin than did monomorphic PVCs (29% vs 9%, P = .008). Repeat ablation procedures were required in 20 patients (20%; 6 had pleomorphic PVCs). Of these 20 patients, 16 (80%) had recurrence of the former predominant PVC, 3 patients (15%) had an increase of a nonpredominant PVC, and 1 patient (5%) had a newly emerging PVC focus. Conclusion The presence of pleomorphic PVCs affects ablation outcomes. Successful elimination of the predominant PVC often results in successful ablation, even if not all PVCs are targeted. Although pleomorphic PVCs infrequently require repeat ablation procedures, most recurrences are due to reemergence of the originally targeted predominant PVC morphology.

Background Sudden cardiac arrest (SCA) is a leading cause of death in the United States (US), claiming up to 450,000 lives annually and accounting for ∼25% of deaths following orthotopic heart transplantation (OHT), Purpose We sought to characterize OHT patients suffering SCA and their subsequent management, in comparison to the general, native heart (NH) population, using a large national inpatient database. Methods A cross-sectional analysis was performed among US OHT & NH patients hospitalized with incident SCA or ventricular fibrillation/flutter. We analyzed demographics, baseline characteristics, procedural utilization and outcomes. Groups were compared with standard statistical techniques. A P-value Results From 2007–2015, 920 SCA admissions were identified among 121,083 (0.8%) OHT hospitalizations, compared to 1,731,658 (0.6%) in the general population (P Table 1. SCA in OHT & general populations Orthotopic Heart Transplant General Population P-value (N=121,083) (N=278,463,550) Sudden cardiac arrest (SCA) events, n (%) 920 (0.8%) 1,731,658 (0.6%) Conclusions SCA hospitalizations occur more often and with higher mortality in OHT patients compared to the general population. Earlier recognition of at-risk patients may result in improved utilization of potentially life-saving therapies.

Introduction: Management of voluminous data from implantable cardiac devices is resource intensive. False positive events can be especially problematic with implantable loop recorders (ILRs). We sought to describe our early experience with a novel ILR. Hypothesis: Sensitivity adjustment to Methods: A single center retrospective study was performed in patients with the Abbott Confirm RX ILR. Tachycardia, atrial fibrillation (AF), bradycardia, and pause events were reviewed to determine whether they were true or false positives. Results: The study included 13 patients (age 67 ±15.8 years, 62% men). The reasons for implant included: AF (n=7, 54%), syncope(n=3, 23%), palpitations (n=2, 15%), and stroke (n=1, 8%). The median follow-up duration was 3.1 months (IQR 1.3-4.4 months). There was no change in serial R waves during mean follow-up of 0.58 months (pre 0.62±0.22 mV, post 0.63±0.22 mV, p=0.52). Tachycardia detection occurred in 6 patients (46%), with only 1 patient having a false positive episode. AF detection occurred in 8 patients (62%), with only 2 patients having true AF episodes. Pause/bradycardia episodes were detected in 5 patients (39%), with false positive episodes in 4 patients. There was no difference in R waves at implant among patients with and without false positive bradycardia/pauses episodes (0.66 ±0.27 vs. 0.44 ± 0.28 mV, p=0.21). The max sensitivity was higher among patients with than without false positive bradycardia/pause episodes (0.14 ±0.01, 0.07 ±0.02 mV, p Conclusion: Programming the novel ILR to a sensitivity of