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Background Atrioventricular (AV) delay in cardiac resynchronisation therapy (CRT) recipients are typically optimised at rest. However, there are limited data on the impact of exercise-induced changes in heart rate on the optimal AV delay and left ventricular function. Methods and results The authors serially programmed AV delays in 41 CRT patients with intrinsic sinus rhythm at rest and during two stages of supine bicycle exercise with heart rates at 20 bpm (stage I) and 40 bpm (stage II) above baseline. The optimal AV delay during exercise was determined by the iterative method to maximise cardiac output using Doppler echocardiography. Results were compared to physiological change in PR intervals in 56 normal controls during treadmill exercise. The optimal AV delay was progressively shortened (p<0.05) with escalating exercise level (baseline: 123±26 ms vs stage I: 102±24 ms vs stage II: 70±22 ms, p<0.05). AV delay optimisation led to a significantly higher cardiac output than without optimisation did during stage I (6.2±1.2 l/min vs 5.2±1.2 l/min, p<0.001) and stage II (6.8±1.6 l/min vs 5.9±1.3 l/min, p<0.001) exercise. A linear inverse relationship existed between optimal AV delays and heart rates in CRT patients (AV delay=241-1.61 x heart rate, R²=0.639, p<0.001) and healthy controls (R²=0.646, p<0.001), but the slope of regression was significantly steeper in CRT patients (p<0.001). Conclusions Haemodynamically optimal AV delay shortened progressively with increasing heart rate during exercise, which suggests the need for programming of rate-adaptive AV delay in CRT recipients. [ABSTRACT FROM AUTHOR]

The article presents a study that determines the effect of cardiac resynchronization therapy (CRT) to patients with drug-refractory heart failure. It reviews the history of CRT which become an integral treatment in patients with drug-refractory congestive heart failure (HF), but there are few who do not respond to CRT. Researchers examined the methods to predict CRT including hemodynamic response, clinical characteristics, electrocardiographic findings, echocardiographic features, multislice computed tomography and cardiac magnetic resonance imaging. The study reveals that CRT is helpful to patients with HF by improving cardiac functions, clinical status, quality of life, exercise capacity and prognosis.

Cardiac resynchronization therapy (CRT) has been shown to improve symptoms, ventricular function, and survival in patients with left ventricular systolic dysfunction and ventricular conduction delay. Patients with moderate to severe drug-refractory heart failure symptoms along with ventricular dyssynchrony, manifested as prolongation of the QRS duration on the surface electrocardiogram, benefit from CRT. Owing to the growing awareness and application of CRT, a large number of patients have been identified as candidates for this therapy, making it necessary for clinicians involved in the care of such patients to be adequately knowledgeable of various aspects of CRT implementation. In particular, clinicians involved in the care of these patients must be aware of the practical considerations in preparing patients for the implantation procedure, careful surveillance for early or late procedure-related complications, and knowledge of the fundamental device features so as to tailor therapeutic and programming techniques to improve long-term response to CRT. This review addresses the technical considerations of the implantation procedure and device function with emphasis on the initial and long-term programming to ensure optimal delivery of CRT. [Copyright &y& Elsevier]

Background Objective Methods Results Conclusion Most studies of device‐detected atrial fibrillation (AF) have recommended indefinite anticoagulation once a patient crosses a particular threshold for AF duration or burden. However, durations and burdens are known to fluctuate over time, but little is known about the magnitude of spontaneous fluctuations and the potential impact on anticoagulation decisions.To quantify spontaneous fluctuations in AF duration and burden in patients with implantable loop recorders (ILRs)We reviewed all ILR interrogations for patients with non‐permanent AF at our institution from 2018 to 2023. We excluded patients treated with rhythm control. The duration of longest AF episode at each interrogation was classified as < 6, 6–24, and > 24 h, and the AF burden reported at each interrogation was classified as < 2%, 2%–11.4%, and > 11.4%.Out of 156 patients, the mean age at ILR implant was 70.9 ± 12.5 years, CHA2DS2‐VASc score was 4.2 ± 1.8, duration of ILR follow‐up was 23.4 ± 11.2 months, and number of ILR interrogations per patient was 18.0 ± 8.9. The duration of longest AF episode at any point during follow‐up was < 6 , 6–24 , and > 24 h in 110, 30, and 16 patients, respectively. Among the 30 patients with a longest AF episode of 6–24 h at some point during follow‐up, out of 594 total ILR interrogations, only 75 (12%) showed a longest episode of 6–24 h. In the remaining 519 interrogations, the longest episode was < 6 h. In patients with a longest episode of > 24 h at any point during follow‐up (n = 16), only 47 out of 320 total ILR interrogations (15%) showed an episode of > 24 h. When evaluating AF burden, 96, 38, and 22 patients had maximum reported AF burdens of < 2%, 2%–11.4%, and > 11.4% at any point during ILR follow‐up. Among those with a maximum burden of 2%–11.4% at some point during follow‐up (n = 38), out of 707 ILR interrogations, only 76 (11%) showed a burden of 2%–11.4%. In the remaining 631 interrogations, the burden was < 2%. In the 22 patients with a burden > 11.4% at some point during follow‐up, only 80 out of 480 interrogations (17%) showed a burden of > 11.4%. In 65% of interrogations, the burden was < 2%.Significant, spontaneous fluctuations in AF burden and duration are common in patients with ILRs. Even in patients with AF episodes of 6–24 h or > 24 h at some point during follow‐up, the vast majority of interrogations show episodes of < 6 h. Similarly, in patients with burdens of 2%–11.4% or > 11.4% at some point during follow‐up, the vast majority of interrogations show burdens of < 2%. More data are needed to determine whether crossing an AF burden or duration threshold once is sufficient to merit lifelong anticoagulation or whether spontaneous fluctuations in AF burden and duration should impact anticoagulation decisions. [ABSTRACT FROM AUTHOR]

BACKGROUND Catheter-based pulmonary vein isolation is an effective treatment for paroxysmal atrial fibrillation. Pulsed field ablation, which delivers microsecond high-voltage electrical fields, may limit damage to tissues outside the myocardium. The efficacy and safety of pulsed field ablation as compared with conventional thermal ablation are not known. METHODS In this randomized, single-blind, noninferiority trial, we assigned patients with drug-refractory paroxysmal atrial fibrillation in a 1:1 ratio to undergo pulsed field ablation or conventional radiofrequency or cryoballoon ablation. The primary efficacy end point was freedom from a composite of initial procedural failure, documented atrial tachyarrhythmia after a 3-month blanking period, antiarrhythmic drug use, cardioversion, or repeat ablation. The primary safety end point included acute and chronic device- and procedure-related serious adverse events. RESULTS A total of 305 patients were assigned to undergo pulsed field ablation, and 302 were assigned to undergo thermal ablation. At 1 year, the primary efficacy end point was met (i.e., no events occurred) in 204 patients (estimated probability, 73.3°/o) who underwent pulsed field ablation and 194 patients (estimated probability, 71.3°/o) who underwent thermal ablation (between-group difference, 2.0 percentage points; 95%> Bayesian credible interval, -5.2 to 9.2; posterior probability of noninferiority, >0.999). Primary safety end-point events occurred in 6 patients (estimated incidence, 2.1°/o) who underwent pulsed field ablation and 4 patients (estimated incidence, 1.5%) who underwent thermal ablation (between-group difference, 0.6 percentage points; 95% Bayesian credible interval, -1.5 to 2.8; posterior probability of noninferiority, >0.999). CONCLUSIONS Among patients with paroxysmal atrial fibrillation receiving a catheter-based therapy, pulsed field ablation was noninferior to conventional thermal ablation with respect to freedom from a composite of initial procedural failure, documented atrial tachyarrhythmia after a 3-month blanking period, antiarrhythmic drug use, cardioversion, or repeat ablation and with respect to device- and procedure-related serious adverse events at 1 year. (Funded by Farapulse-Boston Scientific; ADVENT ClinicalTrials.gov number, NCT04612244). [ABSTRACT FROM AUTHOR]

Pulmonary vein isolation (PVI) is the cornerstone tor ablative management of atrial fibrillation. Traditional mapping using a circular catheter collects electrograms (EGMs) along the circumference of the vein. Cardiac fibers, however, enter the veins at oblique angles. Due to variable fiber orientation and wavefront activation which may produce signal cancelation, fractionation and collision events, signals near fibrotic tissue and along ablation lines may not be detected. Hi-definition (HD) mapping with the Advisor™ HD Grid Mapping Catheter, Sensor Enabled™ addresses this problem by mapping in multiple directions. The unique 16 electrode (4X4 pattern) Advisor™ HD Grid Mapping Catheter, Sensor Enabled™ coupled with HD Wave Solution™ software helped reduce the issue of "bipolar blindness." Coupled with Ensite™ Omnipolar Technology (OT) algorithm that derives a wavesfront's direction and speed, this hardware-software solution allows for the rapid mapping of both overt and occult gaps in pulmonary vein isolation lines. In so doing, this technology offers the potential for faster procedures with precisely targeted lesions, fewer complications, and improved durability. The following article explores the role of Advisor™ HD Grid Mapping Catheter, Sensor Enabled™, HD Wave Solution™ software and EnSite™ Omnipolar Technology in identification of gaps in lesion sets following PVI. [ABSTRACT FROM AUTHOR]

Emerging evidence suggests a link between atrial fibrillation and subsequent development of dementia. While a majority of risk can be attributed to cardioembolic stroke secondary to atrial fibrillation, additional risk is apparent, and may be driven by vascular inflammation and changes in cerebral perfusion. Medical therapies including anticoagulation, statin therapy, and angiotensin-renin-aldosterone axis antagonists may reduce dementia risk. Procedural therapies such as atrial fibrillation catheter ablation and left atrial appendage closure may also prove to be important mediators of acute and long-term risk. In this paper, we review the data supporting a link between atrial fibrillation and dementia syndromes, pathophysiologic mechanisms and the potential roles of medical and procedural therapies at reducing such risk. [ABSTRACT FROM AUTHOR]

Background: Pulmonary vein (PV) reverse remodeling has been recognized following atrial fibrillation (AF) ablation. However, the extent of physiologic reverse remodeling after AF ablation and the potential impact of reverse remodeling on the radiographic diagnosis of PV stenosis have not been well characterized. Methods: From January 2004 to February 2014, 186 patients underwent paired cardiac magnetic resonance imaging (MRI) to delineate PV orifice dimensions before and after (mean 109 ± 61 days) an initial AF ablation. Results: Negative remodeling of the PV orifice cross sectional area occurred in 67.8% of veins with a mean reduction in area of 21.0 ± 14.1%, and positive remodeling was seen in the remaining PVs with an increase in area of 22.1 ± 23.4% compared to baseline. No PVs demonstrated a reduction in cross-sectional area of > 75% (maximum reduction observed was 58%). Negative remodeling of the PV long axis dimension was observed in 55.2% of veins with a mean reduction of 14.6 ± 9.2% compared to pre-ablation and positive remodeling was observed in 25.3% of PVs with a mean increase in diameter of 14.7 ± 12.6%. Only 1 PV demonstrated a reduction in orifice diameter of > 50%. There were no clinically evident or suspected cases of PV stenosis in this cohort. Conclusions: Negative remodeling of the PV orifice area was noted in the majority of PVs following AF ablation. However, in almost all cases, the extent of negative remodeling was well below commonly used thresholds for the radiographic diagnosis of PV stenosis. [ABSTRACT FROM AUTHOR]

Evaluates the technique for quantifying the frequency spectrum of atrial fibrillation (AF) using the surface electrocardiogram. Relation between the morphology of the fibrillatory baseline on the electrocardiogram and the underlying heart disease; Comparison of surface electrocardiogram and endocardial recordings.

The treatment of AF has evolved over the past decade with increasing use of catheter ablation in patients refractory to medical therapy. While pulmonary vein isolation using endocardial catheter ablation has been successful in paroxysmal AF, the results have been more controversial in patients with long-standing persistent AF where extrapulmonary venous foci are increasingly recognised in the initiation and maintenance of AF. Hybrid ablation is the integration of minimally invasive epicardial ablation with endocardial catheter ablation, and has been increasingly used in this population with better results. The aim of this article was to analyse and discuss the evidence for the integration of catheter and minimally invasive surgical approaches to treat AF with specific focus on convergent ablation and exclusion of the left atrial appendage using a surgically applied clip., Competing Interests: Disclosure: AK, KM, NS, DD, YG and FY received consulting fees from Atricure. All other authors have no conflicts of interest to declare., (Copyright © 2020, Radcliffe Cardiology.)

Background: The performance of Abbott/St. Jude Medical (Sylmar CA) Tendril pacing leads has not been well characterized., Objective: We sought to assess the performance of Tendril leads as compared with that of different pacing leads., Methods: We retrospectively identified patients implanted with the following leads: Tendril leads 1888 TC, 2088 TC, and 1688 TC, Medtronic (Fridely, MN) 4076 CapSureFix Novus, and Boston Scientific (Natick, MA) FINELINE II Sterox Pacing EZ leads (models 4469, 4470, and 4471). The primary end point was the incidence of lead malfunction assessed by Kaplan-Meier analysis., Results: During the study period, 9782 leads were implanted, including 8512 Tendril leads, 731 Medtronic 4076 CapSureFix Novus leads, and 539 FINELINE II leads. A total of 540 leads (5.5%) malfunctioned during a mean follow-up of 3.6 ± 2.9 years. Lead malfunction manifested predominantly as noise and/or low impedance (95%). Lead malfunction rates were significantly higher at 5 years for Tendril vs non-Tendril leads (7.0% vs 2.1%; P < .001). The highest rate of failure at 5 years was seen in the Tendril 1888 TC leads (9.9%), followed by Tendril 1688 (5.7%) and Tendril 2088 (5.2%) leads. In contrast, malfunction rates were significantly lower for the Medtronic 4076 (2.6%) and FINELINE II (1.7%) leads. During follow-up to 10 years, the incidence of lead malfunction for Optim-insulated Tendril leads (models 1888 TC and 2088 TC) was significantly higher than that for the non-Optim-insulated Tendril 1688 TC lead (24.5% vs 7.1%) (P = .008)., Conclusion: Tendril leads appear to have a higher rate of malfunction than do comparator leads. Optim insulation may partly explain the higher failure rate., (Copyright © 2018 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

The epidemic of atrial fibrillation (AF) requires a comprehensive management strategy that uses the full force of available data and technology, including anticoagulation, ablative therapy, and left atrial appendage occlusion. Patient-centered care with an emphasis on shared decision-making is particularly relevant to the authors' understanding of the complexity of AF and has helped them tailor therapy in this ever-growing patient population., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Background: Pulmonary vein (PV) reverse remodeling has been recognized following atrial fibrillation (AF) ablation. However, the extent of physiologic reverse remodeling after AF ablation and the potential impact of reverse remodeling on the radiographic diagnosis of PV stenosis have not been well characterized. Methods: From January 2004 to February 2014, 186 patients underwent paired cardiac magnetic resonance imaging (MRI) to delineate PV orifice dimensions before and after (mean 109 ± 61 days) an initial AF ablation. Results: Negative remodeling of the PV orifice cross sectional area occurred in 67.8% of veins with a mean reduction in area of 21.0 ± 14.1%, and positive remodeling was seen in the remaining PVs with an increase in area of 22.1 ± 23.4% compared to baseline. No PVs demonstrated a reduction in cross-sectional area of > 75% (maximum reduction observed was 58%). Negative remodeling of the PV long axis dimension was observed in 55.2% of veins with a mean reduction of 14.6 ± 9.2% compared to pre-ablation and positive remodeling was observed in 25.3% of PVs with a mean increase in diameter of 14.7 ± 12.6%. Only 1 PV demonstrated a reduction in orifice diameter of > 50%. There were no clinically evident or suspected cases of PV stenosis in this cohort. Conclusions: Negative remodeling of the PV orifice area was noted in the majority of PVs following AF ablation. However, in almost all cases, the extent of negative remodeling was well below commonly used thresholds for the radiographic diagnosis of PV stenosis.

Background: Novel atrial fibrillation (AF) ablation tools have been designed to facilitate "single-shot" pulmonary vein (PV) isolation using multi-electrode or balloon-based catheters. However, in contrast to point-by-point radiofrequency ablation, these tools may be more dependent on suitable PV anatomy to achieve circumferential PV isolation., Methods: Three hundred and twenty-two patients underwent gadolinium-enhanced cardiac magnetic resonance angiography to delineate PV anatomy prior to initial AF ablation. Long (a) and short (b) axis measurements of the PV orifice were used to calculate the eccentricity index of the PV ostium., Results: Long axis dimensions of the left superior PV were 18.2 ± 3.3 mm, left inferior PV 17.7 ± 3.9 mm, right superior PV (RSPV) 20.4 ± 4.3, and right inferior PV 18.7 ± 4.7 mm. The long axis dimension of the RSPV was significantly larger than other PVs (p < 0.001). Forty-two patients (13 %) had at least one PV with a long axis dimension >25 mm and 16 patients (5 %) had at least one PV with a long axis dimension >28 mm. Left-sided PV ostia were significantly more ellipse-shaped than the right-sided PVs, which tended to be more spherical. A significant positive correlation was noted between increasing PV size and increased orifice eccentricity., Conclusions: In this large cohort undergoing initial AF ablation, over 10 % of patients had at least one standard PV with a dimension >25 mm. Additionally, significant differences were noted between left- and right-sided veins with regard to orifice eccentricity. These findings have implications for the design of AF ablation tools and may account for differential isolation rates between PVs noted in some recent studies of novel ablation technologies.

Emerging evidence suggests a link between atrial fibrillation and subsequent development of dementia. While a majority of risk can be attributed to cardioembolic stroke secondary to atrial fibrillation, additional risk is apparent, and may be driven by vascular inflammation and changes in cerebral perfusion. Medical therapies including anticoagulation, statin therapy, and angiotensin-renin-aldosterone axis antagonists may reduce dementia risk. Procedural therapies such as atrial fibrillation catheter ablation and left atrial appendage closure may also prove to be important mediators of acute and long-term risk. In this paper, we review the data supporting a link between atrial fibrillation and dementia syndromes, pathophysiologic mechanisms and the potential roles of medical and procedural therapies at reducing such risk.

Purpose: Cardiac sarcoidosis (CS) patients are at increased risk for sudden death. Isolated CS is rare and can be difficult to diagnose., Methods: In this multicenter retrospective review, patients with CS and an implantable cardiac defibrillator (ICD) were identified., Results: Of 235 patients with CS and ICD, 13 (5.5 %) had isolated CS, including 7 (3.0 %) with definite isolated CS (biopsy or necropsy-proven) and 6 (2.6 %) with suspected isolated CS based on a constellation of clinical, ECG, and imaging findings. Among 13 patients with isolated CS, 10 (76.9 %) were male, mean age was 53.8 ± 7.6 years, and mean left ventricular ejection fraction was 38.3 ± 16.5. Diagnosis was made by cardiac magnetic resonance (CMR) (n = 2), biopsy (n = 3), CMR and biopsy (n = 2), CMR and positron emission tomography (PET) (n = 2), PET (n = 1), late enhanced cardiac CT (n = 1), pathology at heart transplant (n = 1), and autopsy (n = 1). Eight of 13 (61.5 %) patients with isolated CS had a secondary prevention indication (VT in 6 and VF in 2) vs. 80 of 222 (36.0 %) with sarcoidosis in other organs (p = 0.04). Over a mean of 4.2 years, 9 of 13 (69.2 %) patients with isolated CS received appropriate ICD therapy, including anti-tachycardia pacing (ATP) and/or shock, compared with 75 of 222 (33.8 %) patients with cardiac and extracardiac sarcoidosis (p = 0.0150). Six of 7 (85.7 %) patients with definite isolated CS received appropriate ICD intervention, compared with 78 of 228 patients (34.2 %) without definite isolated CS (p = 0.0192.), Conclusions: In this retrospective study, patients with isolated CS had very high rates of appropriate ICD therapy. Prospective, long-term follow-up of consecutive patients with isolated CS is needed to determine the true natural history and rates of ventricular arrhythmias in this rare and difficult-to-diagnose disease.

The aim of this study was to create a simple risk index to predict new-onset atrial fibrillation (AF) after coronary artery bypass grafting in patients with histories of AF. AF after coronary artery bypass grafting (referred to here as AF) is associated with increased morbidity and mortality. Identifying patients at high risk for developing AF may help identify a group of patients who might benefit from strategies to prevent postoperative AF. A cohort of 18,517 patients enrolled from January 1, 1996, to December 31, 2009, was used to derive a risk index for AF prediction. A multivariate logistic regression model determined the independent predictive impact of clinical and demographic characteristics on the occurrence of AF. A subset of these variables was used to construct a risk index to predict AF. This risk index was validated in a sequential cohort of 1,378 consecutive patients who underwent coronary artery bypass grafting from January 1, 2010, to June 30, 2011. AF occurred in 3,486 patients in the calibration cohort (18.83%) and in 269 patients in the validation cohort (19.52%). After considering patients' demographics, co-morbid conditions, and severity of illness, advanced age appeared as the most powerful predictor of AF (odds ratio 1.059/year, 95% confidence interval 1.055 to 1.063). Age, height, weight, and the presence of peripheral vascular disease contributed most to the prediction model. An AF risk index including these variables had adequate discriminatory power, with a concordance index of 0.68. In conclusion, using a large cohort of patients, a simple risk index relying only on preoperative clinical variables was developed, which will help predict AF. This risk index can be used clinically to identify patients at high risk for the development of AF., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Heart sounds based measurements such as S3 amplitude and systolic timing intervals (STIs) are known to be indicative of cardiac dysfunction. In this paper we investigate the correlation of these measurements from pacemaker device implant locations to echocardiographic hemodynamic metrics of E wave deceleration time (EDT), Ejection Fraction (EF) and Stroke Volume (SV). Simultaneous heart sounds and echocardiography measurements were made in 6 heart failure patients with cardiac resynchronization therapy (CRT) devices prior to CRT activation (baseline) and at 3 and 6 months post-CRT. In N=17 datasets, S3 amplitude was correlated to EDT (r=-0.86, p<0.05). Similarly STIs such as heart sounds based pre-ejection period (HSPEP) was correlated with EF (r = -0.81, p<0.01) and ejection time (HSET) with SV (r = 0.65, p=0.01). Longitudinal analysis in each patient showed consistent changes between % increase in S3 vs. % decrease in EDT (r= -0.83, p<0.01), % change in HSPEP vs. % change in EF (r= -0.80, p=0.03) and % change in SV (r= -0.72, p< 0.01). These results show proof of concept for using pacemaker derived measurements for monitoring HF patients. Further study is needed to determine their efficacy for chronic monitoring of HF patients.