Anatomical location of leadless pacemaker and the risk of pacing-induced cardiomyopathy.

BACKGROUND: It is unclear if the location of implantation of the leadless pacemaker (LP) makes a difference in the incidence of pacing-induced cardiomyopathy (PICM). AIM: The aim of this study was to compare the incidence of PICM based on the location of implantation of LP. METHODS: A total of 358 consecutive patients [women: 171 (48%), mean age: 73 ± 15 years] with left ventricular ejection fraction (EF) > 50%, who received an LP (Micra) between January 2017 and June 2022, formed the study cohort. Micra-AV and Micra-VR were implanted in 122 (34%) and 236 (66%) patients, respectively. Fluoroscopically, the location of implantation of LP in the interventricular septum (IS) was divided into two equal halves (apex/apical septum [AS] and mid/high septum [HS]). During follow-up, PICM was defined as an EF drop of ≥10%. RESULTS: LP was implanted in 109 (34%) and 249 (66%) patients at AS and HS locations, respectively. During a mean 18 ± 8 months follow-up, 28 patients (7.8%) developed PICM. Among the 249 patients with HS placement of LP, 10 (4%) developed PICM, whereas among the 109 patients with AS placement of LP, 18 (16.5%) developed PICM (p = .002). AS location was associated with a higher risk of PICM compared to HS locations (adjusted hazard ratio: 4.42, p < .001). CONCLUSION: AS location of LP was associated with a higher risk of PICM compared to HS placement. Larger randomized studies are needed to confirm our findings.

In-hospital complications associated with pulmonary vein isolation with adjunctive lesions: the NCDR AFib Ablation Registry.

AIMS: No prior study has been adequately powered to evaluate real-world safety outcomes in those receiving adjunctive ablation lesions beyond pulmonary vein isolation (PVI). We sought to evaluate characteristics and in-hospital complications among patients undergoing PVI with and without adjunctive lesions. METHODS AND RESULTS: Patients in the National Cardiovascular Data Registry AFib Ablation Registry undergoing first-time atrial fibrillation (AF) ablation between 2016 and 2020 were identified and stratified into paroxysmal (PAF) and persistent AF, and separated into PVI only, PVI + cavotricuspid isthmus (CTI) ablation, and PVI + adjunctive (superior vena cava isolation, coronary sinus, vein of Marshall, atypical atrial flutter lines, other). Adjusted odds of adverse events were calculated using multivariable logistic regression. A total of 50 937 patients [PAF: 30 551 (60%), persistent AF: 20 386 (40%)] were included. Among those with PAF, there were no differences in the adjusted odds of complications between PVI + CTI or PVI + adjunctive when compared with PVI only. Among persistent AF, PVI + adjunctive was associated with a higher risk of any complication [3.0 vs. 4.5%, odds ratio (OR) 1.30, 95% confidence interval (CI) 1.07-1.58] and major complication (0.8 vs. 1.4%, OR 1.56, 95% CI 1.10-2.21), while no differences were observed in PVI + CTI compared with PVI only. Overall, there was high heterogeneity in adjunctive lesion type, and those receiving adjunctive lesions had a higher comorbidity burden. CONCLUSION: Additional CTI ablation was common without an increased risk of complications. Adjunctive lesions other than CTI are commonly performed in those with more comorbidities and were associated with an increased risk of complications in persistent AF, although the current analysis is limited by high heterogeneity in adjunctive lesion set type.

Left Atrial Appendage Closure with Watchman vs Amulet Devices: Similarities and Differences.

PURPOSE OF REVIEW: Left atrial appendage closure (LAAC) has shown to be non-inferior to oral anticoagulation (OAC) for non-valvular atrial fibrillation (AF). LAAC is now becoming a leading method for stroke prophylaxis in patients who have atrial fibrillation and are unable to tolerate OAC. There are currently two FDA-approved endocardial closure devices, namely, the Watchman FLX and Amplatzer Amulet. RECENT FINDINGS: Current data highlights that both devices offer similar efficacy and safety for LAAC. While the two devices differ in terms of intraprocedural complication rates, they offer similar short- to long-term outcomes in regard to peri-device leaks, device-related thrombosis, and mortality. With similar risk and safety profiles, both devices are indicated for patients who are unable to tolerate OAC. Newer clinical studies are directed to establish the efficacy of both devices as the primary method for stroke prevention in AF as an alternate to OAC.

Continuous cardiac rhythm monitoring post-stroke: A feasibility study in REGARDS.

OBJECTIVES: Cardiac rhythm monitoring is increasingly used after stroke. We studied feasibility of telephone guided, mail-in ambulatory long-term cardiac rhythm monitoring in Black and White stroke survivors. MATERIALS AND METHODS;: We contacted 28 participants of the Reasons for Geographic and Racial Differences in Stroke (REGARDS) study who had an ischemic stroke during follow-up. After obtaining informed consent by telephone, a noninvasive 14-day cardiac rhythm monitoring device (ZIO® XT patch; iRhythm Technologies, San Francisco, CA) was mailed to each participant. We evaluated the results of telephone consent, follow-up calls, compliance and wear time as the primary objective. Secondarily, we reported prevalence of atrial and ventricular arrhythmias. RESULTS: The majority of those contacted (20/28 = 71%) agreed to enroll in the monitoring study. Non-participation was nominally more common in Black than White participants; 6/16 (37.5%) vs. 2/12 (17%). Of those who agreed, 15 participants (75%, 6 Black, 9 White) completed ambulatory monitoring with mean wear time 12.9 ± 2.5 days. Arrhythmias were observed in two-thirds of the 15 participants: AF in 2, brief atrial tachycardia in 12, NSVT in 2, premature ventricular contractions in 3, and pause or atrioventricular block in 2. CONCLUSIONS: Non-invasive rhythm monitoring was feasible in this pilot from a large, national cohort study of stroke survivors that employed a telephone guided, mail-in monitoring system, and these preliminary results suggest a high prevalence of arrhythmias. Increased emphasis on recruitment strategies for Black stroke survivors may be required. We demonstrated a high yield of significant cardiac arrhythmias among post-stroke participants who completed monitoring.

Arrhythmic Complications Associated with Cancer Therapies.

Over the last several decades, advancements in cancer screening and treatment have significantly improved cancer mortality and overall quality of life. Unfortunately, non-cancer-related side effects, including cardiovascular toxicities can impact the continued delivery of these treatments. Arrhythmias are an increasingly recognized class of cardiotoxicity that can occur as a direct consequence of the treatment or secondary to another type of toxicity such as heart failure, myocarditis, or ischemia. Atrial arrhythmias, particularly atrial fibrillation (AF) are most commonly encountered, however, ventricular- and bradyarrhythmias can also occur, albeit at lower rates. Treatment strategies tailored to patients with cancer are essential to allow for the safe delivery of the cancer treatment without affecting short- or long-term oncologic or cardiovascular outcomes.

Continuous rhythm monitoring-guided anticoagulation after atrial fibrillation ablation.

INTRODUCTION: Oral anticoagulation (OAC) based on estimated stroke risk is recommended following catheter ablation (CA) of atrial fibrillation (AF), regardless of the extent of arrhythmia control. However, discontinuing OAC in selected patients may be safe. We sought to evaluate a strategy of OAC discontinuation following AF ablation guided by continuous rhythm monitoring. METHODS AND RESULTS: We prospectively studied AF ablations performed at our institution from June 2015 to December 2019. Patients that had pre-existing cardiac implantable electronic devices (CIEDs) or underwent insertable cardiac monitor (ICM) implantation immediately following AF ablation were included. OAC was continued for 6 weeks following CA in all patients, following which OAC management was guided by CHA2 DS2 -VASc score and continuous rhythm monitoring results, according to a prespecified protocol. AF recurrence was defined as ≥30 s (CIEDs) or ≥2 min (ICM). We studied 196 patients (mean age 64.7 ± 11.3 years, 66.8% male, 85.7% ICM, 14.3% CIEDs). Mean CHA2 DS2- VASc score was 2.2 ± 1.5. One-year AF-free survival following CA was 83% for paroxysmal AF and 63% for persistent AF patients. Over 3 year follow-up, OAC was discontinued in 57 (33.7%) patients, mean 7.4 ± 7.1 months following ablation. Following discontinuation, OAC was restarted for AF recurrence in 9 (15.8%) patients, mean 11.7 ± 6.8 months after stopping. This discontinuation protocol led to a 21.9% reduction in overall time exposed to OAC. There were no thromboembolic or major bleeding events. CONCLUSION: OAC can be discontinued in a significant percentage of patients following CA of AF. When guided by continuous rhythm monitoring, this practice does not unacceptably increase the risk of thromboembolic events.

Catheter ablation of atrial arrhythmias following lung transplant: Electrophysiological findings and outcomes.

INTRODUCTION: Data on the mechanisms of atrial arrhythmias (AAs) and outcomes of catheter ablation (CA) in lung transplantation (LT) patients are insufficient. We evaluated the electrophysiologic features and outcomes of CA of AAs in LT patients. METHODS AND RESULTS: We conducted a retrospective study of all the LT patients who underwent CA for AAs at our institution between 2004 and 2019. A total of 15 patients (43% males, age: 61 ± 10 years) with a history of LT (60% bilateral and 40% unilateral) were identified. All patients had documented organized AA on surface electrocardiogram and seven patients also had atrial fibrillation (AF; 47% with >1 clinical arrhythmia). At electrophysiological study, 19 organized AAs were documented (48% focal and 52% macro-re-entrant). Focal atrial tachycardias/flutters were targeted along the pulmonary vein (PV) anastomotic site at the left inferior PV (n = 2), ridge and carina of the left superior PV (n = 2), left atrium (LA) posterior wall (n = 3), LA roof (n = 1), and tricuspid annulus (n = 1). Macro-re-entrant AAs included cavotricuspid isthmus-dependent flutter (n = 2), incisional LA flutter (n = 4), LA roof-dependent flutter (n = 1), and mitral annular flutter (n = 3). In patients with LA mapping (n = 13), PV reconnection on the side of the LT was found in six patients (40%, all with clinically documented AF), with a mean of 2.1 ± 0.9 PVs reconnected per patient. Patients with AF underwent successful PV isolation. After a median follow-up of 19 months (range: 6-86 months), 75% of patients remained free from recurrent AAs. No procedural major complications occurred. CONCLUSION: In patients with prior LT, recurrent AAs are typically associated with substrate surrounding the surgical anastomotic lines and/or chronically reconnected PVs. CA of AAs in this population is safe and effective to achieve long-term arrhythmia control.

Endovascular occlusion balloon-related thrombosis during transvenous lead extraction.

AIMS: The aim of this study is to evaluate the incidence, predictors, and outcomes of balloon-related thrombosis (BRT) in patients undergoing transvenous lead extraction (TLE). Use of an endovascular occlusion balloon has improved outcomes of superior vena cava injuries during TLE. Its thrombogenicity in clinical practice is unknown. METHODS AND RESULTS: We prospectively evaluated consecutive patients undergoing prophylactic balloon placement during TLE utilizing two procedural workflows: one with the balloon within the inferior vena cava during the entire case (standard cohort) and one limiting the balloon's dwell time (abbreviated cohort). Intracardiac echocardiography was used to evaluate for significant BRT (thrombus > 1 cm) after TLE. Forty-two patients (21 in each group) were included. Age, left ventricular ejection fraction, procedural indication, number of leads, and lead dwell time were similar between the groups. Balloon dwell time was significantly longer in the standard group (128 ± 74 vs. 25 ± 18 min, P < 0.001) as was BRT (14/21 vs. 1/21, P < 0.001). Mean thrombus length and width in the standard group was 3.99 ± 1.40 and 0.45 ± 0.16 cm, respectively and 5.2 × 0.4 cm in one patient in the abbreviated group. Between patients with and without BRT in the standard group, balloon dwell times were similar (113 ± 64 vs. 156 ± 88 min, P = 0.21). One patient in the standard group had a pulmonary embolism on post-operative Day 3 and was initiated on oral anticoagulation. CONCLUSION: Prophylactic balloon placement for the entirety of the case is associated with a high incidence of BRT; a finding that is decreased when an abbreviated workflow is utilized.

A left ventricular assist device interfering with leadless pacemaker implantation.

Left ventricular assist devices (LVAD) produce electromagnetic interference (EMI) which can have implications when patients require cardiac implantable electronic devices. Leadless pacemakers have been successfully implanted in patients with Heartmate 2 and Heartmate 3 LVADs without evidence of EMI or device-to-device interaction. Here we report a case of a Heartmate 3 LVAD and Micra VR transcatheter pacing system interaction requiring device repositioning.

Pacemaker malfunction? What is the mechanism?

Pacing artifacts on ECG are commonly encountered in clinical practice. We present a case of an external interference from a chronic retained abdominal generator leading to an ECG manifestation of atria lead malfunction. Careful attention to history and physical examination can identify sources of external pacemaker artifact.

An unusual tachycardia - Tale of a hidden P wave.

Traditional rules of arrhythmia mechanisms may not apply in altered anatomical states such as heart transplantation. We present a case of a young man presenting with incessant tachycardia that violates routine electrocardiographic criteria for rhythm analysis. Meticulous attention to surgical techniques and anastomotic sites is crucial when approaching post-operative arrhythmias.

Long-term outcomes of patent foramen ovale closure or medical therapy after cryptogenic stroke: A meta-analysis of randomized trials.

OBJECTIVES: To examine long-term clinical outcomes with transcatheter patent foramen ovale (PFO) closure versus medical therapy alone in patients with cryptogenic stroke. BACKGROUND: A long-standing debate regarding the optimal approach for the management of patients with PFO after a cryptogenic stroke exists. METHODS: An electronic search was performed for randomized clinical trials (RCTs) reporting clinical outcomes with PFO closure vs. medical therapy alone after stroke. Random effects DerSimonian-Laird risk ratios (RR) were calculated. The main outcome was recurrence of stroke. Other outcomes included transient ischemic attack (TIA), new-onset atrial fibrillation/flutter (AF/AFL), major bleeding, serious adverse events, and device-related complications. All-cause mortality was also examined. RESULTS: Five RCTs with a total of 3,440 patients were included. At a mean follow-up of 4.02 ± 1.57 years, PFO closure was associated with less recurrence of stroke (RR = 0.43; 95% CI 0.19-0.91; P = .027) compared with medical therapy alone. No difference was observed between both strategies for TIA (P = .21), major bleeding (P = .69), serious adverse events (P = .35), and all-cause death (P = .48). However, PFO closure, was associated with increased new-onset AF/AFL (P < .001), risk of pulmonary embolism (P = .04), and device-related complications (P < .001). On a subgroup analysis, stroke recurrence rate remained lower in PFO closure arm regardless of the type of closure device used (Pinteraction = .50), or the presence of substantial shunt in the majority of study population (Pinteraction = .13). CONCLUSIONS: Transcatheter PFO closure reduces the recurrence of stroke compared with medical therapy alone, with no significant safety concerns. Close follow-up of patients after PFO closure is recommended to detect new-onset atrial arrhythmias.

Infections, atherosclerosis, and coronary heart disease.

Atherosclerosis is a chronic inflammatory disease. Pathophysiological similarities between chronic infections and atherosclerosis triggered interest in a clinical association between these conditions. Various infectious microbes have been linked to atherosclerotic vascular disease in epidemiological studies. However, this association failed to satisfy the Koch's postulates of causation with multiple clinical trials demonstrating inefficacy of anti-infective therapies in mitigating atherosclerotic cardiovascular events. Identification of underlying pathophysiological mechanisms and experience with vaccination against various infectious agents has ushered a new avenue of efforts in the development of an anti-atherosclerotic vaccine. Studies in animal models have identified various innate and adaptive immune pathways in atherosclerosis. In this review, we discuss the patho-biological link between chronic infections and atherosclerosis, evaluate existing evidence of animal and human trials on the association between infections and cardiovascular disease and introduce the concept of an anti-atherosclerotic vaccine.

Oxidative Stress in Atherosclerosis.

PURPOSE OF REVIEW: Atherosclerosis is now considered a chronic inflammatory disease. Oxidative stress induced by generation of excess reactive oxygen species has emerged as a critical, final common mechanism in atherosclerosis. Reactive oxygen species (ROS) are a group of small reactive molecules that play critical roles in the regulation of various cell functions and biological processes. Although essential for vascular homeostasis, uncontrolled production of ROS is implicated in vascular injury. Endogenous anti-oxidants function as checkpoints to avoid these untoward consequences of ROS, and an imbalance in the oxidant/anti-oxidant mechanisms leads to a state of oxidative stress. In this review, we discuss the role of ROS and anti-oxidant mechanisms in the development and progression of atherosclerosis, the role of oxidized low-density lipoprotein cholesterol, and highlight potential anti-oxidant therapeutic strategies relevant to atherosclerosis. RECENT FINDINGS: There is growing evidence on how traditional risk factors translate into oxidative stress and contribute to atherosclerosis. Clinical trials evaluating anti-oxidant supplements had failed to improve atherosclerosis. Current studies focus on newer ROS scavengers that specifically target mitochondrial ROS, newer nanotechnology-based drug delivery systems, gene therapies, and anti-miRNAs. Synthetic LOX-1 modulators that inhibit the effects of Ox-LDL are currently in development. Research over the past few decades has led to identification of multiple ROS generating systems that could potentially be modulated in atherosclerosis. Therapeutic approaches currently being used for atheroslcerotic vascular disease such as aspirin, statins, and renin-angiotensin system inhibitors exert a pleiotropic antioxidative effects. There is ongoing research to identify novel therapeutic modalities to selectively target oxidative stress in atherosclerosis.

A novel stent inflation protocol improves long-term outcomes compared with rapid inflation/deflation deployment method.

BACKGROUND: High-pressure inflation for coronary stent deployment is universally performed. However, the duration of inflation is variable and does not take into account differences in lesion compliance. We developed a standardized "pressure optimization protocol" (POP) using inflation pressure stability rather than an arbitrary inflation time or angiographic balloon appearance for stent deployment. Whether this approach improves long-term outcomes is unknown. METHODS AND RESULTS: 792 patients who underwent PCI using either rapid inflation/deflation (n = 376) or POP (n = 416) between January 2009 and March 2014 were included. Exclusion criteria included PCI for acute myocardial infarction, in-stent restenosis, chronic total occlusion, left main, and saphenous vein graft lesions. Primary endpoint was target vessel failure [TVF = combined end point of target vessel revascularization (TVR), myocardial infarction, and cardiac death]. Outcomes were analyzed in the entire cohort and in a propensity analysis. Stent implantation using POP with a median follow-up of 1317 days was associated with lower TVF compared with rapid inflation/deflation (10.1 vs. 17.8%, P < 0.0001). This difference was driven by a decrease in TVR (7 vs. 10.6%, P = 0.0016) and cardiac death (2.9 vs. 5.8%, P = 0.017) while there was no difference in myocardial infarction (1 vs. 1.9%, P = 0.19). In the Cox regression model, deployment using POP was the only independent predictor of reduced TVF (HR 0.43; 0.29-0.64; P < 0.0001). In the propensity analysis (330 patients per group) TVF remained lower with POP vs. rapid inflation/deflation (10 vs. 18%, P < 0.0001). CONCLUSIONS: Stent deployment using POP led to reduced TVF compared to rapid I/D. These results recommend this method to improve long-term outcomes. © 2017 Wiley Periodicals, Inc.

Immunity, Inflammation, and Oxidative Stress in Heart Failure: Emerging Molecular Targets.

PURPOSE: Heart failure (HF) remains a major cause of morbidity and mortality worldwide. Although various therapies developed over the last two decades have shown improved long term outcomes in patients with established HF, there has been little progress in preventing the adverse cardiac remodeling that initiates HF. To fill the gap in treatment, current research efforts are focused on understanding novel mechanisms and signaling pathways. Immune activation, inflammation, oxidative stress, alterations in mitochondrial bioenergetics, and autophagy have been postulated as important pathophysiological events in this process. An improved understanding of these complex processes could facilitate a therapeutic shift toward molecular targets that can potentially alter the course of HF. METHODS: In this review, we address the role of immunity, inflammation, and oxidative stress as well as other novel emerging concepts in the pathophysiology of HF that may have therapeutic implications. CONCLUSION: Based on the experimental and clinical studies presented here, we anticipate that a better understanding of the pathophysiology of HF will open the door for new therapeutic targets. A one-size-fits-all approach may not be appropriate for all patients with HF, and further clinical trials utilizing molecular targeting in HF may result in improved outcomes.

"The Scalpel or the Needle for Superior Vena Cava syndrome"?

Acute Superior Vena Cava (SVC) syndrome from thrombosis is an increasingly recognized complication of intravascular devices. We present a 31 year old woman with an infusion port placed for chemotherapy who developed acute SVC obstruction. A computerized tomograpy (CT) of chest revealed an occlusive thrombus within the SVC extending into the right atrium. Catheter-guided thrombolysis and surgical thrombectomywere felt to impose prohibitive risks. Worsening symptoms led to the use of systemic thrombolysis with tissue plasminogen activator (t-PA) leading to dramatic improvement in symptoms. A repeat CT revealed a reduction of the right atrial thrombus and SVC occlusion had resolved.

Contemporary Management of Cardiac Implantable Electronic Device Infection: The American College of Cardiology COGNITO Survey.

Background: Cardiac implantable electronic devices (CIEDs) infection remains a serious complication, causing increased morbidity and mortality. Early recognition and escalation to definitive therapy including extraction of the infected device often pose challenges. Objectives: The purpose of this study was to assess U.S.-based physicians current practices in diagnosing and managing CIED infections and explore potential extraction barriers. Methods: An observational survey was performed by the American College of Cardiology including U.S. physicians managing CIEDs from February to March 2022. Sampling techniques and screener questions determined eligibility. The survey featured questions on knowledge and experience with CIED infection patients and case scenarios. Results: Of 387 physicians completing the survey (20% response rate), 49% indicated familiarity with current guidelines regarding CIED infection. Electrophysiologists (EPs) (91%) were more familiar with these guidelines, compared to non-EP cardiologists (29%) and primary care physicians (23%). Only 30% of physicians specified that their institution had guideline-based protocols in place for managing patients with CIED infection. When presented with pocket infection cases, approximately 89% of EPs and 50% of non-EP cardiologists would follow guideline recommendation to do complete CIED system removal, while 70% of primary care physicians did not recommend guideline-directed treatment. Conclusions: There are gaps in familiarity of guidelines as well as the knowledge in practical management of CIED infection with non-extracting physicians. Most institutions lack a definite pathway. Addressing discrepancies, including guideline education and streamlining care or referral pathways, will be a key factor to bridging the gap and improving CIED infection patient outcomes.