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INTRODUCTION: Survival in patients awaiting cardiac transplantation is poor due to the severity of left ventricular dysfunction and the susceptibility to ventricular arrhythmia. The potential role of implantable cardioverter defibrillators (ICDs) in this group of patients has been the subject of increasing interest. The aims of this study were to ascertain whether ICDs improve the survival rate of patients on the waiting list for cardiac transplantation and whether any improvement is independent of concomitant beta-blocker or amiodarone therapy. METHODS AND RESULTS: Data comprised findings from 310 consecutive patients at a single center who were evaluated and deemed suitable for cardiac transplantation and placed on the waiting list. Kaplan-Meier actuarial approach was used for survival analysis. Survival analysis censored patients at time of transplantation or death. Of the 310 patients, 111 (35.8%) underwent successful cardiac transplantation and 164 (52.9%) died while waiting; 35 patients remain on the waiting list. Fifty-nine (19%) patients had ICD placement for ventricular arrhythmias prior to or after being listed. Twenty-nine (49.1%) ICD patients survived until cardiac transplantation, 13 (22%) patients died, and 17 (28.8%) remain on the waiting list. Among non-ICD patients, 82 (32.7%) received transplants, 151 (60.2%) died, and 18 (7.2%) remain on the waiting list. Survival rates at 6 months and 1, 2, 3, and 4 years were better for all ICD patients compared to non-ICD patients (log-rank x2, P = 0.0001). By multivariate analysis, ICD therapy and beta-blocker treatment were the strongest predictors of survival. Further, ICD treatment was associated with improved survival independent of concomitant treatment with beta-blocker or amiodarone. Among ICD and non-ICD patients treated with a beta-blocker or amiodarone, survivals at the 1 and 4 years were 93% vs 69% and 57% vs 32%, respectively (log-rank x2, P = 0.003). CONCLUSION: ICD therapy is associated with improved survival in high-risk cardiac transplant candidates, and ICD benefit appears to be independent of concomitant treatment. [ABSTRACT FROM AUTHOR]

Acute passive fixation atrial lead dislodgment occurred due to an unexpected and marked postural descent of the heart after permanent pacemaker implantation in two patients. Sagging of the heart in these two individuals may have been related to a history of morbid obesity followed by weight loss of over 100 pounds. Lead replacement with active fixation leads was required in both cases. The term 'sagging heart syndrome' is proposed to describe this clinical entity. In certain adult populations, such as in patients with a history of significant weight loss, the 'sagging heart syndrome' may represent a previously unrecognized cause of acute lead dislodgment. [ABSTRACT FROM AUTHOR]

INTRODUCTION: Syncope occasionally may occur in the supine patient due to severe brady- or tachyarrhythmia. However, recurrent syncope upon assumption of the supine position as a result of a neurally mediated reflex mechanism has not been reported previously. METHODS AND RESULTS: Two young patients, both of whom had significant systemic illnesses, experienced recurrent episodes of presyncope and/or syncope shortly after assuming the supine position. During ambulatory ECG monitoring, symptoms were provoked only by lying down and were associated with transient bradycardia. Head-up tilt table testing was undertaken as part of the syncope evaluation and was nondiagnostic in both cases. However, both patients exhibited a transient cardioinhibitory response with reproduction of typical symptoms upon return of the table to the supine position ('reverse tilt'). During follow-up (8 and 14 months), both patients improved with pharmacologic treatment (disopyramide in one case and midodrine in the other). CONCLUSION: Presyncope or syncope upon lying down can be an unusual manifestation of the neurally mediated faint. [ABSTRACT FROM AUTHOR]

Patients commonly present with syncope at emergency departments and other facilities for urgent care. Syncope is understood by physicians to be a transient, self-terminating period of cerebral hypoperfusion that usually results from systemic hypotension, and clinical guidelines for the care of patients with presumed syncope are available. However, the diagnosis and management of such patients continue to pose important diagnostic, therapeutic, and economic challenges, which are the focus of this Review. First, we discuss how to improve symptom characterization to distinguish syncope from other forms of transient loss of consciousness and syncope mimics. Second, we compare methods of risk stratification in patients with suspected syncope, and recommend the introduction of syncope clinics with enhanced interdisciplinary collaboration to optimize patient care at reduced expense. Third, we highlight the importance of the appropriate selection of diagnostic tools and treatment strategies in these syncope clinics. Finally, we address the difficulties associated with therapy for the most-common form of syncope--vasovagal or reflex syncope. [ABSTRACT FROM AUTHOR]

Purpose: The Compendium of Physical Activities is commonly recognized as an adjuvant to prescribing physical activities and estimating energy expenditure. But its applicability in clinical populations is less clear. Thus, the purpose of this study was to measure the metabolic cost of activities of daily living in volunteers implanted with an integrated sensor pacemaker and compare these values with those in the compendium.Methods: On the first day of testing, patients underwent a symptom-limited cardiopulmonary graded exercise test using the Minnesota Pacemaker Response Exercise protocol. The next day, an Activities of Daily Living protocol was performed in a model apartment in the exercise physiology lab. Energy expenditure and heart rate response were measured during 5 common activities of daily living: vacuuming, changing bed linens, carrying and unpacking groceries, changing and folding laundry, and walking on a treadmill. Measured values (mean +/- SD) were compared with compendium values using a one-sample t-test. Relative intensity was established using peak measurements obtained during the graded exercise test.Results: The mean MET values achieved during all 5 activities of daily living were significantly higher than those listed in the compendium. The relative demands of the activities of daily living, as expressed as a percentage of VO2 peak, ranged from 46 to 62%.Conclusion: When prescribing exercise or physical activities for individuals with rate-responsive pacemakers, direct measurement vs. estimation of energy expenditure would seem prudent, as the energy requirements of activities of daily living may not be accurately estimated by the compendium. [ABSTRACT FROM AUTHOR]

This study compared alterations in arterial catecholamine concentrations associated with tilt-induced vasovagal syncope that differed in older (>65 years) and younger patients (<35 years). Older patients with tilt-positive tests tended to exhibit higher baseline epinephrine (E) concentrations and lesser E surge before development of syncope than younger patients (<35 years), whereas both groups manifested comparable norepinephrine (NE) responsiveness. [ABSTRACT FROM AUTHOR]

This study surveyed current practice patterns with respect to the manner by which cardiac arrhythmia specialists advise patients with vasovagal syncope regarding resumption of motor vehicle operation. Among 66 physician-respondents from 9 countries, 98% indicated that they rely on tilt-table testing to establish a diagnosis, and, if an effective treatment is found based on serial tilt-table testing, they recommend a 6- to 7-week symptom-free waiting period before advising return to driving. [ABSTRACT FROM AUTHOR]

People with epilepsy are at risk of premature death, of which sudden unexpected death in epilepsy (SUDEP), sudden cardiac death (SCD) and sudden arrhythmic death syndrome (SADS) are the primary, partly overlapping, clinical scenarios. We discuss the epidemiologies, risk factors and pathophysiological mechanisms for these sudden death events. We reviewed the existing evidence on sudden death in epilepsy. Classification of sudden death depends on the presence of autopsy and expertise of the clinician determining aetiology. The definitions of SUDEP, SCD and SADS lead to substantial openings for overlap. Seizure-induced arrhythmias constitute a minority of SUDEP cases. Comorbid cardiovascular conditions are the primary determinants of increased SCD risk in chronic epilepsy. Genetic mutations overlap between the states, yet whether these are causative, associated or incidentally present is often unclear. Risk stratification for sudden death in people with epilepsy requires a multidisciplinary approach, including a review of clinical history, toxicological analysis and complete autopsy with histologic and, preferably, genetic examination. We recommend pursuing genetic testing of relatives of people with epilepsy who died suddenly, mainly if a post-mortem genetic test contained a Class IV/V (pathogenic/likely pathogenic) gene variant. Further research may allow more precise differentiation of SUDEP, SCD and SADS and the development of algorithms for risk stratification and preventative strategies., Competing Interests: N.A.S., D.G.B. and K.Z. report no conflicts of interest. R.D.T. has received personal compensation for serving on the Advisory Boards or Speaker’s Bureau for Xenon, Theravance, Novartis, Esai, Angelini Pharma and UCB. J.W.S. or his department has received grants from Esai, Angelini Pharma and UCB. He has received personal compensation for serving on the Advisory Boards or Speaker’s Bureau for UCB and Angelini Pharma., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Guarantors of Brain.)

Syncope is a symptom in which transient loss of consciousness occurs as a consequence of a self-limited, spontaneously terminating period of cerebral hypoperfusion. Many circulatory disturbances (e.g. brady- or tachyarrhythmias, reflex cardioinhibition-vasodepression-hypotension) may trigger a syncope or near-syncope episode, and identifying the cause(s) is often challenging. Some syncope may involve multiple etiologies operating in concert, whereas in other cases multiple syncope events may be due to various differing causes at different times. In this communication, we address the current understanding of the principal contributors to syncope pathophysiology including examination of the manner in which concepts evolved, an overview of factors that constitute consciousness and loss of consciousness, and aspects of neurovascular control and communication that are impacted by cerebral hypoperfusion leading to syncope. Emphasis focuses on 1 ) current understanding of the way transient systemic hypotension impacts brain blood flow and brain function; 2 ) the complexity and temporal sequence of vascular, humoral, and cardiac factors that may accompany the most common causes of syncope; 3 ) the range of circumstances and disease states that may lead to syncope; and 4 ) clinical features associated with syncope and in particular the reflex syncope syndromes.

Background: Atrial fibrillation (AF) increases risk of embolic stroke, and in postoperative patients, increases cost of care. Consequently, ECG screening for AF in high-risk patients is important but labor-intensive. Artificial intelligence (AI) may reduce AF detection workload, but AI development presents challenges., Methods and Results: We used a novel approach to AI development for AF detection using both surface ECG recordings and atrial epicardial electrograms obtained in postoperative cardiac patients. Atrial electrograms were used only to facilitate establishing true AF for AI development; this permitted the establishment of an AI-based tool for subsequent AF detection using ECG records alone. A total of 5 million 30-second epochs from 329 patients were annotated as AF or non-AF by expert ECG readers for AI training and validation, while 5 million 30-second epochs from 330 different patients were used for AI testing. AI performance was assessed at the epoch level as well as AF burden at the patient level. AI achieved an area under the receiver operating characteristic curve of 0.932 on validation and 0.953 on testing. At the epoch level, testing results showed means of AF detection sensitivity, specificity, negative predictive value, positive predictive value, and F1 (harmonic mean of positive predictive value and sensitivity) as 0.970, 0.814, 0.976, 0.776, and 0.862, respectively, while the intraclass correlation coefficient for AF burden detection was 0.952. At the patient level, AF burden sensitivity and positive predictivity were 96.2% and 94.5%, respectively., Conclusions: Use of both atrial electrograms and surface ECG permitted development of a robust AI-based approach to postoperative AF recognition and AF burden assessment. This novel tool may enhance detection and management of AF, particularly in patients following operative cardiac surgery.

Purpose: We compared hemodynamic parameters between subjects with marked, intermediate and minimal cardioinhibition during vasovagal syncope., Methods: The study included subjects with a decrease in heart rate while experiencing a complete vasovagal syncope during tilt-table testing. The subjects were classified as having marked, intermediate or minimal cardioinhibition, based on tertile values of the decrease in heart rate. Hemodynamic parameters between these groups were compared before tilt in the supine position, shortly after tilt and during cardioinhibition., Results: A total of 149 subjects with a median age of 43 (interquartile range 24-60) years were included in the study. Among the three groups with different levels of cardioinhibition, the highest heart rate was observed in subjects with marked cardioinhibition both before and shortly after tilt and at the start of cardioinhibition. The heart rate decrease in these subjects was both larger and faster compared to subjects with minimal and intermediate cardioinhibition., Conclusion: Subjects with marked cardioinhibition have both a larger and faster decrease in heart rate compared to subjects with intermediate and minimal cardioinhibition, as early as from the start of cardioinhibition. Marked cardioinhibition is related to differences in hemodynamic profiles already present well before the start of cardioinhibition., (© 2023. The Author(s).)

Sinus node dysfunction (SND) is a multifaceted disorder most prevalent in older individuals, but may also occur at an earlier age. In most cases, the SND diagnosis is ultimately established by documenting its ECG manifestations. EPS has limited utility. The treatment strategy is largely dictated by symptoms and ECG manifestations. Not infrequently, both bradycardia and tachycardia coexist in the same patients, along with other diseases common in the elderly (e.g., hypertension, coronary artery disease), thereby complicating treatment strategy. Prevention of the adverse consequences of both bradyarrhythmia and tachyarrhythmia is important to reduce susceptibility to syncope, falls, and thromboembolic complications., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Atrial fibrillation (AF) is the most common cardiac arrhythmia and if untreated, significantly increases both the risk of intracardiac thrombus formation and ischemic stroke. In patients with nonvalvular AF (NVAF), the left atrial appendage (LAA) has been estimated to be the source of thrombus development in 91% to 99% of cases. Consequently, oral anticoagulation (OAC) to provide stroke prevention has become the standard of care for most AF patients; however, OACs are associated with a risk of bleeding and their efficacy depends on optimal patient compliance. In terms of alternative approaches to preventing embolic events, surgical LAA excision was attempted as early as in the late 1940s in patients with valvular AF; LAA excision remains a recommendation in surgical guidelines for NVAF patients who need open-heart coronary bypass or valvular replacement/repair surgeries. However, due to its invasive nature surgical LAA intervention has limited clinical application in present cardiology practice. Percutaneous LAA occlusion (LAAO) is increasingly being performed as an alternative to OAC for stroke prevention; this is particularly the case in patients at increased bleeding risk. Substantial progress has been made in percutaneous LAAO therapy since its inception some twenty years ago. Herein we systematically review both the critical literature that led to the development of LAAO, and the increasing clinical evidence supporting the application of this treatment strategy in NVAF. To this end we focus on recently published critical evaluations of United States Food and Drug Administration (US FDA) and Conformité Européenne (Commercial Sale of Licensed Product in the EU) (CE-Mark) approved LAAO devices, summarize the current status of LAAO therapy, and discuss the future perspectives regarding the knowledge and technology gaps in this area by recognizing the potential contributions of many ongoing but likely transformative clinical trials., Competing Interests: Dr. Han reports no conflict of interest. Dr. Benditt is a consultant for and/or has equity in Medtronic Inc, Abbott Labs and Advanced Circulatory Systems. Dr Benditt is supported in part by a grant from the Dr Earl E Bakken family., (Copyright: © 2023 The Author(s). Published by IMR Press.)

Aims: Inappropriate sinus tachycardia (IST) is a syndrome characterized by an elevated sinus rate unassociated with known physiological, pathological, or pharmacological causes. Despite published consensus documents, IST definitions appear to vary in the literature. In this study, we reviewed IST publications to evaluate IST definition variability and ascertain the degree to which consensus definitions are being adopted., Methods and Results: English-language articles in PubMed, Ovid MEDLINE, Ovid Embase, and Google Scholar published from 1 January 1970 to 1 June 2021 with the title terms 'inappropriate sinus tachycardia,' 'non-paroxysmal sinus tachycardia,' or 'permanent sinus tachycardia' were searched. In each, the IST definition used, qualifying characteristics, and publications cited to support each definition were recorded. We identified 138 publications meeting the search criteria. Inappropriate sinus tachycardia definitions were provided in 114 of 138 articles (83%). A majority of definitions (92/114, 81%) used distinct heart rate (HR) thresholds. Among these, the most common threshold was ≥100 beats per minute (BPM) (75/92, 82%), mainly measured at rest (54/92, 59%). Most definitions (47/92, 51%) included a second criterion to qualify for IST; these were most often an HR threshold of 90 BPM measured over 24 h by ambulatory electrocardiogram (37/47, 79%). Diagnosis of exclusion was a common criterion (75/92, 82%) but symptom status was not (41/92, 45%). The 2015 Heart Rhythm Society IST consensus was commonly cited but adopted in only 37% of definitions published after 2015., Conclusions: Inappropriate sinus tachycardia definitions in current literature are inconsistent, and professional society consensus IST definitions have, to date, had limited impact., Competing Interests: Conflict of interest: None declared., (© The Author(s) 2022. Published by Oxford University Press on behalf of the European Society of Cardiology. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Background: Persistent atrial fibrillation (AF) is a complex arrhythmia, and attaining freedom from AF with ablation has been challenging., Objectives: This study evaluated a novel CARTO software algorithm based on the CARTO Ripple map for AF termination and 18-month freedom from AF., Methods: Consecutive patients who underwent first-time ablation for persistent AF were included. A high-density Ripple map was created using a Pentaray catheter. Following PVI, ablation was performed at locations with rapid Ripple activations, a protocol previously described by us. Patients were followed for 18 months to assess rhythm outcomes. A retrospective analysis was performed using the CARTO Ripple frequency software algorithm. The Ripple frequency algorithm quantifies amplitude changes in the bipolar electrogram., Results: A total of 115 AF maps were analyzed from 84 patients (mean age 65.9 years, 63.1% men). The top quartile of Ripple frequency corresponded to a visual reference with 96.7% sensitivity and 91.1% specificity. AF terminated during ablation in 88.1% of patients: pulmonary vein antrum alone (14.9%) or pulmonary vein plus nonantral sites (85.1%). The top quartile of Ripple frequency was present in nonantral areas associated with AF termination with 90.2% sensitivity and 86.5% specificity. After 14.0 ± 6.5 months and 1.2 ± 0.4 ablations, 78 (92.9%) of 84 patients were free of AF, and 79.8% were free of any atrial arrhythmia., Conclusion: A novel algorithm for automated analysis of CARTO Ripple frequency demonstrated good sensitivity and specificity for detecting atrial regions in persistent AF in which ablation is associated with frequent AF termination and freedom from AF during follow-up., (© 2022 Heart Rhythm Society. Published by Elsevier Inc.)

Competing Interests: Conflict of interest The authors declare that they have no conflict of interest.

Background: Cardioinhibition may diminish with age, but the changing balance of cardioinhibition and vasodepression with age has not been quantified, leaving the mechanism of vasovagal syncope (VVS) in old age unclear., Objectives: This study sought to quantify age-related changes of vasodepression and cardioinhibition in tilt-induced VVS., Methods: We studied 163 cases of tilt-induced VVS, evoked using the Italian protocol with blood pressure, heart rate, and video-electroencephalographic monitoring. Presyncope was excluded. Cardioinhibition was defined as the heart rate decrease before syncope; asystolic pauses (≥3 seconds) were divided into early and late asystole, ie, beginning early enough to or too late to be the major cause of loss of consciousness. The log-ratio method was used to quantify contributions of cardioinhibition and vasodepression, assessed in 2 10-second periods before the onset of cardioinhibition and before syncope., Results: With increasing age, cardioinhibition decreased, ie, heart rate decreased less and more slowly near syncope (P < 0.0001), while vasodepression increased. Asystolic pauses were less frequent in the older one-half of the group than the younger one-half (26% vs 57%; P < 0.00001), but when it did, late asystole occurred more often (58% vs 15%; P < 0.001)., Conclusions: The shift toward less cardioinhibition and more vasodepression with increased age probably reflects a physiological shift in circulatory control. The weakening of cardioinhibition with age may detract from the efficacy of pacing in older patients with VVS. Cardioinhibition-vasodepression balance should be considered in pacing decisions in older subjects with VVS., Competing Interests: Funding Support and Author Disclosures Dr de Lange has received consulting fees from Medtronic Inc, Abbott, and Daiichi-Sankyo. Dr Thijs has received consulting and speaker fees from Union Chimique Belge, GlaxoSmithKline, Theravarance, Arvelle, Novartis, and Zogenix; and has received grants from Dutch National Epilepsy Fund, Michael J. Fox Foundation for Parkinson's Research (MJFF-020200), Christelijke Vereniging voor de Verpleging van Lijders aan Epilepsie, Medtronic Inc, New Life Wearables, and the Netherlands Organisation for Health Research and Development (114025101). Dr Sutton has served as a consultant to Medtronic Inc; has been a member of the Speakers Bureau of Abbott Corp (St. Jude Medical); and is a stockholder of Edwards Lifesciences Corp and Boston Scientific Corp. Dr Benditt has served as a consultant to Medtronic Inc; and is a stockholder of Advanced Circulatory Systems. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2022 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Sinus node dysfunction (SND) is a multifaceted disorder most prevalent in older individuals, but may also occur at an earlier age. In most cases, the SND diagnosis is ultimately established by documenting its ECG manifestations. EPS has limited utility. The treatment strategy is largely dictated by symptoms and ECG manifestations. Not infrequently, both bradycardia and tachycardia coexist in the same patients, along with other diseases common in the elderly (e.g., hypertension, coronary artery disease), thereby complicating treatment strategy. Prevention of the adverse consequences of both bradyarrhythmia and tachyarrhythmia is important to reduce susceptibility to syncope, falls, and thromboembolic complications., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Introduction: In patients with ictal asystole (IA) both cardioinhibition and vasodepression may contribute to syncopal loss of consciousness. We investigated the temporal relationship between onset of asystole and development of syncope in IA, to estimate the frequency with which pacemaker therapy, by preventing severe bradycardia, may diminish syncope risk., Methods: In this retrospective cohort study, we searched video-EEG databases for individuals with focal seizures and IA (asystole ≥ 3 s preceded by heart rate deceleration) and assessed the durations of asystole and syncope and their temporal relationship. Syncope was evaluated using both video observations (loss of muscle tone) and EEG (generalized slowing/flattening). We assumed that asystole starting ≤3 s before syncope onset, or after syncope began, could not have been the dominant cause., Results: We identified 38 seizures with IA from 29 individuals (17 males; median age: 41 years). Syncope occurred in 22/38 seizures with IA and was more frequent in those with longer IA duration (median duration: 20 [range: 5-32] vs. 5 [range: 3-9] s; p < .001) and those with the patient seated vs. supine (79% vs. 46%; p = .049). IA onset always preceded syncope. In 20/22 seizures (91%), IA preceded syncope by >3 s. Thus, in only two instances was vasodepression rather than cardioinhibition the dominant presumptive syncope triggering mechanism., Conclusions: In IA, cardioinhibition played an important role in most seizure-induced syncopal events, thereby favoring the potential utility of pacemaker implantation in patients with difficult to suppress IA., (© 2021 The Authors. Journal of Cardiovascular Electrophysiology published by Wiley Periodicals LLC.)