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Background: Implantable cardioverter defibrillators (ICD) are indicated for primary and secondary prevention of sudden cardiac arrest. Despite enhancements in design and technologies, the ICD lead is the most vulnerable component of the ICD system and failure of ICD leads remains a significant clinical problem. A novel, small‐diameter, lumenless, catheter‐delivered, defibrillator lead was developed with the aim to improve long‐term reliability. Methods and Results: The Lead Evaluation for Defibrillation and Reliability (LEADR) study is a multi‐center, single‐arm, Bayesian, adaptive design, pre‐market interventional pivotal clinical study. Up to 60 study sites from around the world will participate in the study. Patients indicated for a de novo ICD will undergo defibrillation testing at implantation and clinical assessments at baseline, implant, pre‐hospital discharge, 3 months, 6 months, and every 6 months thereafter until official study closure. Patients may be participating for a minimum of 18 months to approximately 3 years. Fracture‐free survival will be evaluated using a Bayesian statistical method that incorporates both virtual patient data (combination of bench testing to failure with in‐vivo use condition data) with clinical patients. The clinical subject sample size will be determined using decision rules for number of subject enrollments and follow‐up time based upon the observed number of fractures at certain time points in the study. The adaptive study design will therefore result in a minimum of 500 and a maximum of 900 patients enrolled. Conclusion: The LEADR Clinical Study was designed to efficiently provide evidence for short‐ and long‐term safety and efficacy of a novel lead design using Bayesian methods including a novel virtual patient approach. [ABSTRACT FROM AUTHOR]

The article offers information on appraisal of high‐power short‐duration radiofrequency ablation for pulmonary vein isolation. Topics discussed include need for strategy being developed for ablation in the left atrium to accomplish transmural lesions with no collateral tissue damage; information on high‐power short duration (HPSD) radiofrequency (RF) application; and informaton on pulmonary vein isolation (PVI) that remains the cornerstone in any ablation strategy.

Catheter ablation is now at the forefront of the management of symptomatic atrial fibrillation (AF). Its role in paroxysmal AF is well defined with considerable data supporting its role. Catheter ablation in persistent AF has been less effective and the subject of considerable debate. Mechanistic studies have demonstrated the critical role of pulmonary vein physiology in paroxysmal AF, whereas the mechanisms that sustain persistent AF are not well understood. Additional substrate ablation in persistent AF has not improved long-term outcomes and the use of novel mapping technologies to assess rotor activity remains controversial. This review will focus on the current understanding of the mechanistic basis of paroxysmal and persistent AF, the role of catheter ablation and, recent advances in the management of these complex arrhythmias. [ABSTRACT FROM AUTHOR]

Since the original description of atrial fibrillation ablation, numerous studies have demonstrated the superiority of catheter ablation over pharmacological therapy for maintenance of sinus rhythm in patients with both paroxysmal and persistent atrial fibrillation. However, to date, no randomized studies have been powered to demonstrate a mortality or stroke reduction benefit of rhythm control with catheter ablation over a rate control strategy. The results of such ongoing studies are not expected until 2018 or 2019. Thus, the only indication for atrial fibrillation ablation in recent guidelines has been the presence of symptoms. However, up to 40% of an atrial fibrillation population may be asymptomatic. In 2017, in the absence of randomized studies, are there nevertheless data that support atrial fibrillation ablation in asymptomatic patients? [ABSTRACT FROM AUTHOR]

Obstructive Sleep Apnea Treatment Prevalence rates of atrial fibrillation (AF) and obstructive sleep apnea (OSA) are rising on a global scale. Epidemiological data have consistently demonstrated an independent association between the 2 conditions. Investigators pose that pathophysiologic features of OSA enable progression of the AF substrate; these features include abnormalities of gas exchange, autonomic remodeling, atrial stretch, and inflammation. Furthermore, many of the mechanistic perturbations that impact the AF substrate in OSA can be substantially attenuated by effective treatment with continuous positive airway pressure (CPAP). Clear associations of OSA treatment and improved AF control have been observed across multiple clinical contexts. However, the precision and generalizability of these findings are unclear in view of the data's observational nature. Although risk factor management has emerged as a critical component of AF treatment, effective control of many AF risk factors can be challenging in the longer term. In view of the efficacy and sustainability of CPAP therapy, OSA raises its profile as a prime candidate for intervention. However, translation of this strategy to the broader framework for AF management requires robust data from randomized controlled trials. [ABSTRACT FROM AUTHOR]

Background: Insertable cardiac monitors (ICMs) are used to continuously monitor the patient's electrocardiogram. In response to patient activation or based on automated device algorithms, arrhythmia episodes are stored and automatically transmitted daily to the clinician. Thus, ICMs can be used to diagnose arrhythmias in at-risk patients and in those with symptoms potentially attributable to arrhythmias. The ICM described in this report has undergone a dramatic change in size and method of insertion. Methods: To evaluate the safety profile of the ICM procedure, we analyzed procedure-related adverse events (AEs) from two separate trials: A controlled, nonrandomized multicenter study (Reveal LINQTM Usability study) and a multicenter registry (Reveal LINQTM Registry) evaluating real-world experience. For the Registry we reported all procedure-related AEs upon occurrence, whereas for the Usability study, we reported events occurring during the first month of follow-up. Results: The Usability study enrolled 151 patients (age 56.6 ± 12.1 years; male 67%) at 16 centers; during follow-up, an infection was observed in 1.3% patients and a procedure-related serious AE (SAE) in 0.7% patients. The Registry enrolled 122 patients (age 61.0 ± 17.8 years; male 47%) at seven centers; during follow-up, an infection was observed in 1.6% patients and a procedure-related SAE in 1.6% patients. Conclusions: The cumulative experience from a controlled clinical trial and a "real-world" registry demonstrate that the new ICM can be inserted with very low incidence of AEs. [ABSTRACT FROM AUTHOR]

The article offers a commentary on a study on atrial fibrillation (AF) frequency mapping using continuous wavelet transform (CWT). Topics covered include the need to determine the substrate responsible for AF specific to individual patient for a more targeted ablative therapy, costs associated with mapping techniques using basket-type catheter and non-invasive body surface electrodes, and the utility of CWT frequency analysis versus fast-Fourier transform (FFT)-derived dominant frequency (DF).

Background: Sudden cardiac death (SCD) during physical exercise is devastating. Aims: To evaluate causes and circumstances of exercise‐related SCD in the young in Australia. Methods: We reviewed the National Coronial Information System database for deaths in Australia relating to cardiovascular disease in cases aged 10–35 years between 2000 and 2016. Cases who had undertaken physical exercise at the time of the event were included. We collected demographics, circumstances of death, type of physical exercise, bystander cardiopulmonary resuscitation (CPR) and automated external defibrillator (AED) use prior to ambulance arrival. Results: Over a 17‐year period, 1925 SCD cases were identified, of which 110 (6%) cases (median age 27 years (interquartile range 21–32 years); 92% male) were related to sports/physical exercise. Thirteen (12%) cases occurred in active athletes. Most common causes were coronary artery disease (CAD; 37%) and sudden arrhythmic death syndrome (SADS; 20%). Among Aboriginal and Torres Strait Islanders (n = 10), all deaths were related to CAD. Australian Rules Football (24%), running/jogging (14%) and soccer (14%) were the most frequent physical exercise activities. Prior symptoms were present in 39% (chest pain 37%, pre‐syncope/syncope 26%). Most (87%) were witnessed, with bystander CPR in 70%. AED use prior to ambulance arrival was 8%. Conclusions: The present study demonstrates the high occurrence of CAD and SADS in SCD in the young related to physical exercise. Aboriginal and Torres Strait Islanders were disproportionately affected by CAD. Although events were commonly witnessed, AED was seldom used prior to ambulance arrival and highlights an important opportunity to improve outcomes in the post‐arrest chain of survival. [ABSTRACT FROM AUTHOR]

The primary analysis of FIRE AND ICE demonstrated that cryoablation was noninferior to radiofrequency ablation for the primary efficacy end point of first documented clinical failure. Secondary analysis suggested that cryoablation had advantages over radiofrequency ablation in terms of rehospitalizations and repeat procedures: however, the validity of these results must be questioned. [ABSTRACT FROM AUTHOR]

Atrial fibrillation (AF) is the most frequent cardiac arrhythmia in clinical practice. AF is often associated with profound functional and structural alterations of the atrial myocardium that compose its substrate. Recently, a relationship between the thickness of epicardial adipose tissue (EAT) and the incidence and severity of AF has been reported. Adipose tissue is a biologically active organ regulating the metabolism of neighbouring organs. It is also a major source of cytokines. In the heart, EAT is contiguous with the myocardium without fascia boundaries resulting in paracrine effects through the release of adipokines. Indeed, Activin A, which is produced in abundance by EAT during heart failure or diabetes, shows a markedfibrotic effect on the atrial myocardium. The infiltration of adipocytes into the atrial myocardium could also disorganize the depolarization wave front favouring micro re-entry circuits and local conduction block. Finally, EAT contains progenitor cells in abundance and therefore could be a source of myofibroblasts producing extracellular matrix. The study on the role played by adipose tissue in the pathogenesis of AF is just starting and is highly likely to uncover new biomarkers and therapeutic targets for AF. [ABSTRACT FROM AUTHOR]

Various forms of heart disease are associated with remodeling of the heart muscle, which results in a perturbation of cell-to-cell electrical coupling. These perturbations may alter the trajectory of spiral wave drift in the heart muscle. We investigate the effect of spatially extended inhomogeneity of transverse cell coupling on the spiral wave trajectory using a simple active media model. The spiral wave was either attracted or repelled from the center of inhomogeneity as a function of cell excitability and gradient of the cell coupling. High levels of excitability resulted in an attraction of the wave to the center of inhomogeneity, whereas low levels resulted in an escape and termination of the spiral wave. The spiral wave drift velocity was related to the gradient of the coupling and the initial position of the wave. In a diseased heart, a region of altered transverse coupling corresponds with local gap junction remodeling that may be responsible for stabilization-destabilization of spiral waves and hence reflect potentially important targets in the treatment of heart arrhythmias. [ABSTRACT FROM AUTHOR]

The article offers information regarding the role of catheter ablation for the treatment of atrial arrhythmias. It discusses three types of atrial arrhythmias which include focal atrial tachycardia, atrial flutter, and atrial fibrillation. It mentions several options for treating arrhythmias which includes antiarrhythmic drugs and cardiac electrophysiology. INSET: Search strategy and selection criteria.

Atrial fibrillation (AF) is the most common clinically important cardiac arrhythmia. It is an important cause of stroke, contributes to the burden of heart failure and is a major contributor to health expenditure. Percutaneous catheter ablation is superior to medical therapy in reducing AF recurrences. It has an important role in treatment of patients with failed drug therapy. Successful catheter ablation improves left ventricular function in patients with heart failure. In addition, it may be appropriate for selected highly symptomatic patients as first line therapy. Catheter ablation for AF has been shown in randomised trials to reduce hospital admissions and improve quality of life. There is evidence from registry data to suggest it reduces the risk of stroke and improves mortality. Cost effectiveness has been demonstrated by modelling studies in both Europe and the United States. [ABSTRACT FROM AUTHOR]

Adjuvant ablation of complex fractionated atrial electrograms (CFAE) in addition to pulmonary vein isolation (PVI) likely improves procedural outcome compared to PVI alone, particularly in patients with persistent atrial fibrillation (AF). However, CFAE regions can be extensive, occasionally requiring a large amount of extra ablation. Some CFAE regions may also represent passive wavefront collision and may not require ablation. Thus, there is interest in identifying more selective CFAE sites that are critical to AF perpetuation, minimizing the amount of adjuvant ablation that must be performed. The SELECT AF study is a prospective, multicenter, randomized trial comparing a strategy of PVI plus generalized CFAE ablation versus a strategy of PVI plus selective CFAE ablation, focusing on regions of continuous electrical activity (CEA). The primary efficacy endpoint is freedom from atrial arrhythmia at 1 year and the primary safety endpoint is total radiofrequency (RF) delivery time per procedure. Patients undergoing a first time ablation procedure for symptomatic persistent AF will be included. Patients with permanent AF or with left atrial size ≥55 mm will be excluded. Patients will all receive PVI at the time of their ablation, but will be randomized 1:1 to receive adjuvant CFAE ablation using the traditional 'generalized' approach, or a 'selective' approach targeting only CEA regions. Both strategies will be guided by automated mapping algorithms. This study will enroll a minimum of 80 evaluable subjects; 40 in each randomization group. SELECT AF is a randomized trial in patients with persistent AF to evaluate the efficacy of selective versus generalized CFAE ablation in addition to traditional PVI. (J Cardiovasc Electrophysiol, Vol. 22, pp. 541-547 May 2011) [ABSTRACT FROM AUTHOR]

Increased consumption of fish and/or fish oil was associated with decreased risk of sudden cardiac death (SCD). The study aim was to evaluate the antiarrhythmic effect of dietary fish oil on the inducibility of ventricular tachycardia (VT) at high risk of SCD. Patients with coronary artery disease undergoing defibrillator implantation were recruited if sustained monomorphic VT could be induced by programmed extra stimuli at 2 cycle lengths. After the initial study, 12 patients consumed 3 g/d of encapsulated fish oil for approximately 6 weeks before a repeated electrophysiologic study. To control for fluctuations in the inducibility of VT, an additional 14 patients with no dietary manipulation were also studied. Aggressiveness of stimulation required to induce VT was ranked from least aggressive to most aggressive based on cycle length and number of extra stimuli, with noninducibility ranked highest. At the repeated electrophysiologic study, in the fish-oil group, 42% had no inducible VT, 42% required more aggressive stimulation to induce VT, 8% required identical stimulation, and 8% required less stimulation compared with 7%, 36%, 36%, and 21% in the control group, respectively. Overall, there was a change to noninducible or less inducible VT in the fish-oil group, but no change in the control group (p = 0.003 and p = 0.65, respectively; Wilcoxon’s sign-rank test). In conclusion, dietary n-3 fatty acid supplementation decreased the inducibility of VT in patients at risk of SCD. These findings suggest that dietary fish oil can have an antiarrhythmic effect. [Copyright &y& Elsevier]

Evidence from noninvasive studies suggests magnesium has a differential effect on atrioventricular nodal (AVN) pathways. To further explore the electrophysiologic effects of intravenous magnesium sulfate (MgSO4) on supraventricular tachycardia, with particular reference to AVN conduction pathways, we studied 23 patients with supraventricular tachycardia at the time of electrophysiologic study. Tachycardia cycle length; AH, HV, and VA intervals; anterograde and retrograde Wenckebach thresholds; slow and fast pathway effective refractory periods (ERPs); accessory pathway ERP; right atrial and ventricular ERPs; blood pressure; and serum magnesium were evaluated before and after administration of MgSO4 during sustained tachycardia. AVN reentry was induced in 14 patients and atrioventricular reentry was induced in 9; 1 of the latter had dual AVN physiology with tachycardia using the slow pathway. Serum magnesium level increased from 0.88 ± 0.11 to 1.79 ± 0.14 mmol/L (p <0.0001). Magnesium increased tachycardia cycle length to a greater extent in those with dual AVN physiology than those without: 340 ± 54 to 370 ± 57 ms versus 347 ± 29 to 350 ± 30 ms (p = 0.01). This was associated with greater increase in AH interval in those with dual AVN physiology than in those without: 241 ± 59 to 270 ± 60 ms versus 144 ± 16 to 140 ± 20 ms (p = 0.003). Presence of dual AVN physiology was more frequently associated with reversion to sinus rhythm: 5 of 15 versus 0 of 8 (p = 0.06). MgSO4 did not alter other measured parameters. In conclusion, magnesium increases tachycardia cycle length and AH interval in patients with dual AVN physiology through a dominant effect on the slow AVN pathway. [Copyright &y& Elsevier]

Sinus node disease was previously thought to be a disease limited to the sinus node and its atrial connections. However, recent reports have demonstrated sinus node disease as a disease of the entire right atrial myocardium. These patients have widespread electrophysiological abnormalities of their atria, including prolonged refractory periods and slowed conduction. In addition to these electrical changes, there are significant structural changes, such as fibrosis and fatty infiltration, which can be detected endocardially as regions of fractionated signals, low-voltage electrograms, and electrically silent areas. In most cases, the etiology of these changes is unknown. These changes may contribute to the high prevalence of atrial fibrillation seen in patients with sinus node disease. [Copyright &y& Elsevier]

Introduction: The pulmonary veins (PVs) are a dominant source of triggers initiating atrial fibrillation (AF). While recent evidence implicates these structures in the maintenance of paroxysmal AF, their role in permanent AF is not known. The current study aims to compare the contribution of PV activity to the maintenance of paroxysmal and permanent AF. Methods and Results: Thirty-four patients with paroxysmal AF (n = 20) or permanent AF (n = 14) undergoing ablation were studied. Prior to ablation, 32 seconds of electrograms were acquired from each PV and the coronary sinus (CS). The frequency of activity of each PV and CS was defined as the highest amplitude frequency on spectral analysis. The effects of ablation on the AF cycle length (AFCL) and frequency and on AF termination were determined. Significant differences were observed between paroxysmal and permanent AF. Paroxysmal AF demonstrates higher frequency PV activity (11.0 ± 3.1 vs 8.8 ± 3.0 Hz; P = 0.0003) but lower CS frequency (5.8 ± 1.2 vs 6.9 ± 1.4 Hz; P = 0.01) and longer AFCL (182 ± 17 vs 158 ± 21 msec; P = 0.002), resulting in greater PV to atrial frequency gradient (7.2 ± 2.2 vs 4.2 ± 2.9 Hz; P = 0.006). PV isolation in paroxysmal AF resulted in a greater decrease in atrial frequency (1.0 ± 0.7 vs −0.05 ± 0.4 Hz; P < 0.0001), greater prolongation of the AFCL (49 ± 35 vs 5 ± 6 msec; P < 0.0001), and more frequent AF termination (11/20 vs 0/14; P = 0.0007) compared to permanent AF. Conclusion: Paroxysmal AF is associated with higher frequency PV activity and lesser CS frequency compared to permanent AF. Isolation of the PVs had a greater impact on the fibrillatory process in paroxysmal AF compared to permanent AF, suggesting that while the PVs have a role in maintaining paroxysmal AF, these structures independently contribute less to the maintenance of permanent AF. [ABSTRACT FROM AUTHOR]

Introduction: We hypothesized that the frequency spectra of fibrillatory electrograms may reflect the complexity of activities perpetuating atrial fibrillation (AF). To test this hypothesis, we evaluated the frequency spectra in patients with paroxysmal AF in relation to catheter ablation. Methods and Results: This study comprised two protocols: 25 patients undergoing pulmonary vein (PV) isolation in protocol I, and 20 patients undergoing mitral isthmus linear ablation after PV isolation in protocol II. The mean of dominant frequency (DF) and organization index (the ratio of the area under the DF and its harmonics to the total power) were determined from 32-second recordings in the coronary sinus. In protocol I, a PV was considered “driver” of AF if isolation of the PV resulted in termination or slowing of AF (decrease in DF by ≥0.25 Hz). Twenty-one patients had AF termination during four PV isolation. Among these 21 patients, 13 patients with single driving PV showed significantly higher baseline organization index than eight patients with multiple driving PVs (0.45 ± 0.08 vs 0.35 ± 0.07, P = 0.009). Patients with multiple driving PVs showed a significant increase in the organization index to 0.45 ± 0.11 (P < 0.05) after isolation of the initial driving PVs. In protocol II, the baseline organization index was significantly higher in seven patients who had termination of AF during mitral isthmus ablation than 13 patients who did not (0.50 ± 0.10 vs 0.38 ± 0.07, P < 0.008). The baseline DF was not associated with outcomes of ablation in both protocols. Conclusions: A higher organization index of atrial electrograms is associated with termination of AF during limited ablation. This parameter may be useful to anticipate the extent of ablation. [ABSTRACT FROM AUTHOR]

Introduction: Organized atrial arrhythmias following atrial fibrillation (AF) ablation are typically due to recovered pulmonary vein (PV) conduction or reentry at incomplete ablation lines. We describe the role of nonablated anterior left atrium (LA) in arrhythmias observed after AF ablation. Methods: A total of 275 consecutive patients with paroxysmal (n = 200) or chronic (n = 75) AF had PV isolation with/without additional linear ablation at the mitral isthmus (n = 106), LA roof (n = 23), or both (n = 88). Organized arrhythmias occurring after ablation were evaluated utilizing activation and entrainment mapping. Results: Fourteen patients (11 female, 65 ± 13 years, 10 chronic AF, 10 structural heart disease) demonstrated tachycardia localized to the anterior LA, an area not targeted by prior ablation. Eight had ECG features during sinus rhythm suggestive of impaired anterior LA conduction at baseline. These arrhythmias demonstrated a distinctive ECG flutter morphology in 7 of 10 (70%) with discrete −/+ or +/−/+ aspect in inferior leads. Mapping the anterior LA revealed electrograms spanning the entire tachycardia cycle length (325 ± 125 msec). Entrainment was possible in all with a postpacing interval exceeding the tachycardia cycle length by 9 ± 10 msec. Electroanatomic mapping in 6 demonstrated small reentrant circuits rotating clockwise in 4 and counterclockwise in 2. Low-amplitude, fractionated mid-diastolic potentials with long duration (200 ± 80 msec) occupying 63 ± 22% of the cycle length were targeted for ablation resulting in termination and subsequent noninducibility. Conclusion: Organized arrhythmias occurring after AF ablation can be due to reentrant circuits localized to the anterior LA, predominantly in females with chronic AF, structural heart disease, and abnormal atrial conduction. They are characterized by a distinctive surface ECG and highly responsive to RF ablation at the slow conduction area. [ABSTRACT FROM AUTHOR]

Objectives: The goal of this study was to characterize the origin of focal atrial tachycardias (AT). Background: Focal ATs originate from a small area and spread centrifugally; however, activation at the AT origin has not been characterized. Methods: Twenty patients with AT having failed prior ablation or occurring after atrial fibrillation ablation were studied. After excluding macro–re-entry, AT was mapped using a 20-pole catheter (five radiating spines; diameter 3.5 cm), performing vector mapping to identify the earliest activity followed by high-density mapping at the AT origin. Localized re-entry was considered if >85% of the tachycardia cycle length (CL) was observed within the mapping field and was confirmed by entrainment. Results: A total of 27 ATs were mapped to the pulmonary vein ostia (n = 5), and left (n = 16) and right atria (n = 6). A localized focus was evidenced at the site of origin in 19 ATs (70%), whereas in 8 (30%), localized re-entry was evidenced by 95.2 ± 4.5% of the tachycardia CL recorded within the mapping field and entrainment showed a post-pacing interval <20 ms longer than tachycardia CL (6 of 6 tested). Localized re-entry had a shorter CL (p = 0.009), slowed conduction at its origin (fractionated potential 115 ± 19 ms vs. 64 ± 22 ms, representing 49 ± 10% and 20 ± 10% of tachycardia CL, respectively; p < 0.0001), and were more often contiguous with regions of electrical silence or conduction abnormalities (88% vs. 32%; p = 0.01). In addition, mapping documented varying degrees of intra-atrial conduction block, preferential conduction (n = 5), and rapid bursts of myocardial activity (n = 1). At 11 ± 7 months, none have had recurrence of AT. Conclusions: High-density multielectrode mapping can be used to perform vector mapping to localize complex AT. It provides novel insight into the mechanisms of focal AT, distinguishing focal AT from localized re-entry. [Copyright &y& Elsevier]

Background: The relative contributions of different atrial regions to the maintenance of persistent atrial fibrillation (AF) are not known. Methods: Sixty patients (53 ± 9 years) undergoing catheter ablation of persistent AF (17 ± 27 months) were studied. Ablation was performed in a randomized sequence at different left atrial (LA) regions and comprised isolation of the pulmonary veins (PV), isolation of other thoracic veins, and atrial tissue ablation targeting all regions with rapid or heterogeneous activation or guided by activation mapping. Finally, linear ablation at the roof and mitral isthmus was performed if sinus rhythm was not restored after addressing the above-mentioned areas. The impact of ablation was evaluated by the effect on the fibrillatory cycle length in the coronary sinus and appendages at each step. Activation mapping and entrainment maneuvers were used to define the mechanisms and locations of intermediate focal or macroreentrant atrial tachycardias. Results: AF terminated in 52 patients (87%), directly to sinus rhythm in 7 or via the ablation of 1–6 intermediate atrial tachycardias (total 87) in 45 patients. This conversion was preceded by prolongation of fibrillatory cycle length by 39 ± 9 msec, with the greatest magnitude occurring during ablation at the anterior LA, coronary sinus and PV-LA junction. Thirty-eight atrial tachycardias were focal (originating dominantly from these same sites), while 49 were macroreentrant (involving the mitral or cavotricuspid isthmus or LA roof). Patients without AF termination displayed shorter fibrillatory cycles at baseline: 130 ± 14 vs 156 ± 23 msec; P = 0.002. Conclusion: Termination of persistent AF can be achieved in 87% of patients by catheter ablation. Ablation of the structures annexed to the left atrium—the left atrial appendage, coronary sinus, and PVs—have the greatest impact on the prolongation of AF cycle length, the conversion of AF to atrial tachycardia, and the termination of focal atrial tachycardias. [ABSTRACT FROM AUTHOR]

This article presents information on curative treatment of atrial fibrillation. Pulmonary veins electrical isolation is performed as the initial strategy in all patients with Atrial Fibrillation. One do not attempt to identify PVs demonstrating anhythmogenicity at the time of the procedure but rather aim to isolate all PVs. No PV angiography is performed routinely. The inferior portion of the PV ostia is localized by advancing the catheter into the PV with downward deflection of the tip and then dragging back while fluoroscopically monitoring the drop off the ostial edge of the catheter. PV isolation is guided by circumferential mapping. Ablation preferentially targets regions of earliest PV activation when it is asynchronous or is performed by gravitating around the PV circumference during sinus rhythm or ongoing AE.

Left Atrial Pacemaker Dominance. We report a case of left atrial dominant rhythm demonstrated by electroanatomic mapping. The rhythm occurred after radiofrequency catheter ablation in a patient with persistent atrial fibrillation and structural heart disease. [ABSTRACT FROM AUTHOR]

Fever and Idiopathic VF. Introduction: Ventricular fibrillation (VF) is the main mechanism of sudden cardiac death. The clinical precipitants of sudden cardiac death due to idiopathic VF are poorly characterized. Emerging evidence implicates triggers originating predominantly from the distal Purkinje arborization and the right ventricular outflow tract. Methods and Results: We report three patients without structural heart disease or repolarization abnormalities in whom a febrile illness was the only concurrent disease associated with unexpected sudden cardiac death due to VF storm. An automated defibrillator was implanted in all three patients. In one patient with persistent recurrent VF episodes, mapping demonstrated the origin of these triggers was from the Purkinje arborization of the anterior wall of the right ventricle. Ablation at a site of earliest activation during ectopy, where pace mapping was concordant and Purkinje potential preceded the onset of ventriculogram, resulted in suppression of all arrhythmias. After follow-up of 22,9, and 18 months in the three patients, no ventricular arrhythmias have been recorded. Conclusion: We present a series of patients in whom an apparently benign febrile illness was associated with malignant ventricular arrhythmias in the absence of cardiac disease or other factors known to precipitate sudden cardiac death. Physicians should be aware of this possible phenomenon in cases of febrile illness associated with syncope. [ABSTRACT FROM AUTHOR]

The goal of this study was to describe the mapping and ablation of polymorphic ventricular tachycardia (VT) after myocardial infarction (MI).The initiating mechanisms of polymorphic VT after MI have not been reported.Five patients (four males; age 61 ± 7 years) with recurrent episodes of polymorphic VT after anterior MI (left ventricular ejection fraction 32 ± 7%) despite revascularization and antiarrhythmic drugs were studied. All patients demonstrated frequent ventricular premature beats (PBs) initiating polymorphic VT. Pace mapping and activation mapping were used to identify the earliest site of PB activity. The presence of a Purkinje potential preceding PB defined its origin from the Purkinje network. Electroanatomic voltage mapping was performed to delineate the extent of MI.The PBs were observed in all cases to arise from the Purkinje arborization in the MI border zone. These PBs were right bundle-branch block in all five patients, with morphologic variations in the limb leads in four; one also had a left bundle-branch block morphology. The coupling interval of the PB to the preceding QRS complex demonstrated significant variations (320 to 600 ms). During PB, the Purkinje potential at the same site preceded the QRS complex by 20 to 160 ms and was associated with different morphologies. Repetitive Purkinje activity was documented during polymorphic VT. Splitting of Purkinje activity and Purkinje to muscle conduction block were also observed. Ablation at these sites eliminated all PBs. At 16 ± 5 months follow-up using defibrillator memory interrogation, no patient has had recurrence of arrhythmia.The Purkinje arborization along the border-zone of scar has an important role in the mechanism of polymorphic VT in patients after MI. Ablation of the local Purkinje network allows suppression of polymorphic VT. [Copyright &y& Elsevier]

Objectives: The purpose of this study was to characterize the pattern of atrial remodeling seen with human aging.Background: Atrial fibrillation (AF) occurs in 3% to 4% of the population over 65 years of age. It is associated with thromboembolic complications, worsening heart failure, and increased mortality, yet the electrical and structural remodeling that occurs with human aging remains unknown.Methods: Thirteen patients (66.4 ± 1.7 years) ≥60 years (group A), 13 patients (50 ± 2.1 years) age 31 to 59 years (group B), and 15 patients (24.7 ± 1.0 years) ≤30 years (group C) underwent conventional electrophysiologic studies and electroanatomic mapping. We measured atrial refractoriness (ERP) at the distal coronary sinus (CS); low and high lateral right atrium (LRA) and the high septal right atrium at 600, 500, and 400 ms; maximum corrected sinus node recovery time (CSNRT); P-wave duration (PWD); conduction time (CT) along the CS and LRA; and discrete double potentials (DP) along the crista.Results: Aging was associated with an increase in atrial ERP, prolonged CT along the CS, increased PWD and CSNRT. There was no significant change in dispersion of refractoriness or rate adaptation. Electroanatomic mapping revealed diffuse areas of low voltage with regional conduction slowing. Both techniques demonstrated a greater number of DPs and fractionated signals along the crista terminalis with aging.Conclusions: Aging is associated with regional conduction slowing, anatomically determined conduction delay at the crista, and structural changes that include areas of low voltage. In addition, impairment of sinus node function and an increase in atrial ERP occurred with aging. This electrical and structural remodeling may explain the increased propensity to AF with aging. [Copyright &y& Elsevier]

Coronary Sinus Disconnection. We report a case of radiofrequency catheter ablation for chronic atrial fibrillation, in which electrical disconnection of the coronary sinus was necessary to isolate a trigger initiating atrial fibrillation. (J Cardiovasc Electrophysiol, Vol. 15, pp. 364-368, March 2004) [ABSTRACT FROM AUTHOR]

: ObjectivesThe study was done to characterize the electrocardiographic and electrophysiologic features of focal atrial tachycardia originating at the mitral annulus (MA).: BackgroundThough the majority of left atrial tachycardias originate around the ostia of the pulmonary veins, only isolated reports have described focal tachycardia originating from the MA.: MethodsSeven patients of a consecutive series of 172 patients undergoing radiofrequency ablation for focal atrial tachycardia are reported. Electrophysiologic study involved catheters positioned along the coronary sinus (CS), crista terminalis (CT), His bundle, and a mapping/ablation catheter.: ResultsAll seven patients had tachycardia foci originating from the superior region of the MA in close proximity to the left fibrous trigone and mitral-aortic continuity. These foci demonstrated a characteristic P-wave morphology and endocardial activation pattern. The P-wave morphology in the precordial leads typically showed a biphasic pattern, with an inverted component followed by an upright component. The P-wave was consistently of low amplitude in the limb leads. Earliest endocardial activity occurred at the His bundle region in all seven patients. In general, CS activation was proximal to distal, and mid-CT activation was earlier than high or low CT. Ablation was successful at the superior aspect of the MA in all patients.: ConclusionsThe MA is an unusual but important site of origin for focal atrial tachycardia, with a propensity to be localized to the superior aspect. It can be suspected as a potential anatomic site of tachycardia origin from analysis of P-wave morphology and the atrial endocardial activation sequence map. Using mapping targeted to anatomic structures achieved a high success rate for ablation. [Copyright &y& Elsevier]

Intracardiac Echocardiography of the Flutter Isthmus. Introduction: Cavotricuspid isthmus (CTI) topography includes ridges, pouches, recesses, and trabeculations. These features may limit the success of radiofrequency ablation (RFA) of typical atrial flutter (AFL). The aim of this study was to assess the utility of phased-array intracardiac echocardiography (ICE) for imaging the CTI and monitoring RFA of AFL. Methods and Results: Fifteen patients (mean age 64 ± 9 years) underwent ICE assessment (imaging frequency 7.5–10 MHz) before and after RFA of AFL. The ICE catheter was positioned at the inferior vena cava-right atrial junction and the following parameters were measured: (1) CTI length from the tricuspid valve to the eustachian ridge; (2) extent of CTI pouching; and (3) thickness pre/post RFA of the anterior, mid, and posterior CTI. CTI length was 35 ± 6 mm at end-ventricular systole but shorter (30 ± 6 mm) and more pouched at end-ventricular diastole (P = 0.02) . A pouch or recess was seen in 11 of 15 patients (mean depth 6 ± 2 mm ). The septal CTI was more pouched than the lateral CTI, but the latter had more prominent trabeculations. Trabeculations were seen in 10 of 15 patients, and at these locations the CTI was 4.6 ± 1 mm thick. Anterior, mid, and posterior CTI thickness pre-RFA was 4.1 ± 0.8, 3.3 ± 0.5 , and 2.7 ± 0.9 mm , respectively ( P < 0.001 by analysis of variance). ICE guided RFA away from unfavorable CTI features (recesses/thick trabeculations). RFA applications created discrete CTI lesions that coalesced, forming diffuse CTI swelling. Post-RFA thickness was as follows: anterior 4.8 ± 0.8 mm (P = NS vs pre); mid 3.8 ± 0.8 mm (P = 0.05 vs pre) ; and posterior 3.8 ± 0.8 mm (P = 0.02 vs pre) . Conclusion: Phased-array ICE permits novel real-time CTI imaging with excellent endocardial resolution and may facilitate RFA of AFL. (J Cardiovasc Electrophysiol, Vol. 14, pp. 591-597, June 2003). [ABSTRACT FROM AUTHOR]

Accessory Pathway in Left Inferoposterior Diverticulum. We report the case of an accessory pathway in a left inferoposterior diverticulum. The pathway masqueraded as a true left lateral pathway due to the direction of activation over a coronary sinus to left atrium connection. The patient had undergone four prior failed ablation attempts at other institutions using both a transseptal and retrograde approach.(J Cardiovasc Electrophysiol, Vol. 14, pp. 403-406, April 2003). [ABSTRACT FROM AUTHOR]

We compared transesophageal and phased-array intracardiac echocardiography (TEE/ICE) for the 2-dimensional and spectral Doppler assessment of left atrial (LA) mechanical function. TEE is commonly used to assess LA body and LA appendage mechanical function in patients who are undergoing radiofrequency ablation of typical atrial flutter. Fifteen patients underwent TEE and ICE imaging before and after ablation of typical atrial flutter. The following parameters were measured: (1) LA appendage emptying velocity and fractional area change, (2) severity of LA spontaneous echo contrast (graded 0 to 4), (3) maximal inflow velocity of the left and right upper pulmonary veins, and (5) maximal mitral valve E- and A-wave inflow velocities in sinus rhythm. Diagnostic quality imaging was achieved in all patients with TEE and ICE. Comparing TEE and ICE, the following absolute values and linear correlation coefficient (R) were obtained: preablation LA appendage emptying velocity: 0.45 ± 0.21 versus 0.44 ± 0.21 m/s (r = 0.95, p = <0.001); postablation LA appendage velocity: 0.33 ± 0.24 versus 0.34 ± 0.24 m/s (r = 0.97, p <0.001); LA appendage fractional area change: 35.3 ± 13.7 versus 35.9 ± 17.1% (r = 0.81, p <0.001); left upper/right upper pulmonary vein inflow velocity: 0.50 ± 0.17/0.49 ± 0.18 versus 0.51 ± 0.17/0.47 ± 0.20 m/s (r = 0.93/0.90, p <0.001); mitral valve E/A wave: 0.66 ± 0.14/0.31 ± 0.14 versus 0.69 ± 0.17/0.35 ± 0.23 (r = 0.84/0.97, p <0.002); LA spontaneous echo contrast (pre- and postablation): 1.1 ± 1.2/1.3 ± 1.2 versus 1.2 ± 1.3/1.4 ± 1.3 (r = 0.92/0.90, p <0.001). No patients were identified with LA appendage thrombus. Thus, TEE and phased-array ICE provided equivalent imaging data with high statistical correlation. ICE may be an imaging alternative to TEE in the evaluation of a “stunned” left atrium. [Copyright &y& Elsevier]

OBJECTIVESThis study was designed to determine the sensitivity and specificity of concealed entrainment (CE) for the identification of a critical isthmus in the atrium.BACKGROUNDIsthmus identification during entrainment mapping of macro-reentrant atrial tachycardia (MRAT) relies on the demonstration of CE.METHODSUsing the model of typical atrial flutter, entrainment was performed in 10 patients at four rates (flutter cycle length [FCL] minus 10/20/30/40 ms) from seven sites: isthmus entrance/exit, low lateral/high lateral/high septal right atrium and proximal/distal coronary sinus. Surface 12-lead electrocardiogram fusion was evaluated by three observers blind to patient status. The extent of antidromic penetration (AP) was measured off the pacing catheter positioned around the tricuspid annulus.RESULTSThe sensitivity for CE identifying any isthmus site was greatest at FCL−10 (100%), but the specificity was poor (54%). Conversely, specificity was greatest at FCL−40 (98%), but the sensitivity was poor (65%), with manifest entrainment (ME) observed from the isthmus entrance in 70% of episodes. At FCL−30, sensitivity (85%) and specificity (90%) were “balanced,” but CE still resulted during entrainment from a non-isthmus site in five of 10 patients. Antidromic penetration increased with pacing CL shortening (p < 0.001) and correlated with the development of ME (p < 0.001). Antidromic penetration was significantly blunted from the isthmus exit compared to all other sites (p = 0.003).CONCLUSIONSThe sensitivity and specificity of CE for identifying an isthmus in the atrium are critically dependent on the pacing rate and the precise anatomic pacing site within the isthmus. These findings may have implications for the use of entrainment in the mapping of unknown MRAT circuits. [Copyright &y& Elsevier]

Studies the effects of anticoagulation on the occurrence of deep venous thrombosis associated with temporary transvenous femoral pacemakers. Key issues of interest; Analysis of pertinent topics and relevant issues; Implications on cardiology.

The efficacy of intravenous magnesium in terminating sustained monomorphic ventricular tachycardia was examined in this study. This therapy was found to be ineffective in aborting monomorphic ventricular tachycardia induced in the electrophysiology laboratory. [ABSTRACT FROM AUTHOR]

Sinus node disease is characterized by the presence of significant sinus bradycardia or prolonged sinus pauses, and is attributed to either primary failure of sinus node automaticity or sino-atrial conduction disturbance. We present two patients with symptomatic bradycardia due to idiopathic global atrial inexcitability. [ABSTRACT FROM AUTHOR]

The article discusses the evolving technique of imaging the atrial fibrillation. It has found out that linear ablation joining anatomical structures and ablation of fractionated electrograms have been used to modify the atrial substrate. In addition, several techniques have been applied to improve catheter navigation during catheter ablation procedures.

LA Appendage Disconnection. We report a case with paroxysmal atrial fibrillation, in whom multiple foci were identified in the left atrial appendage after pulmonary vein isolation. The patient was successfully treated by catheter ablation to disconnect this structure. (J Cardiovasc Electrophysiol, Vol. 16, pp. 1-3, August 2005) [ABSTRACT FROM AUTHOR]

This study reports that patients with large body mass indexes (BMIs) and long-duration atrial fibrillation (AF) have greater defibrillation thresholds than patients with normal BMIs and AF of short duration. BMI is an independent predictor of defibrillation thresholds in patients with longer duration AF in whom external cardioversion has failed. [Copyright &y& Elsevier]

Background: Exercise-induced cardiac remodeling can be profound, resulting in clinical overlap with dilated cardiomyopathy, yet the significance of reduced ejection fraction (EF) in athletes is unclear. The aim is to assess the prevalence, clinical consequences, and genetic predisposition of reduced EF in athletes. Methods: Young endurance athletes were recruited from elite training programs and underwent comprehensive cardiac phenotyping and genetic testing. Those with reduced EF using cardiac magnetic resonance imaging (defined as left ventricular EF <50%, or right ventricular EF <45%, or both) were compared with athletes with normal EF. A validated polygenic risk score for indexed left ventricular end-systolic volume (LVESVi-PRS), previously associated with dilated cardiomyopathy, was assessed. Clinical events were recorded over a mean of 4.4 years. Results: Of the 281 elite endurance athletes (22±8 years, 79.7% male) undergoing comprehensive assessment, 44 of 281 (15.7%) had reduced left ventricular EF (N=12; 4.3%), right ventricular EF (N=14; 5.0%), or both (N=18; 6.4%). Reduced EF was associated with a higher burden of ventricular premature beats (13.6% versus 3.8% with >100 ventricular premature beats/24 h; P=0.008) and lower left ventricular global longitudinal strain (-17%±2% versus -19%±2%; P<0.001). Athletes with reduced EF had a higher mean LVESVi-PRS (0.57±0.13 versus 0.51±0.14; P=0.009) with athletes in the top decile of LVESVi-PRS having an 11-fold increase in the likelihood of reduced EF compared with those in the bottom decile (P=0.034). Male sex and higher LVESVi-PRS were the only significant predictors of reduced EF in a multivariate analysis that included age and fitness. During follow-up, no athletes developed symptomatic heart failure or arrhythmias. Two athletes died, 1 from trauma and 1 from sudden cardiac death, the latter having a reduced right ventricular EF and a LVESVi-PRS >95%. Conclusions: Reduced EF occurs in approximately 1 in 6 elite endurance athletes and is related to genetic predisposition in addition to exercise training. Genetic and imaging markers may help identify endurance athletes in whom scrutiny about long-term clinical outcomes may be appropriate. REGISTRATION: URL: https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=374976&isReview=true Unique identifier: ACTRN12618000716268. [ABSTRACT FROM AUTHOR]

Background: Anticoagulation can prevent most strokes in individuals with atrial fibrillation (AF); however, many people presenting with stroke and known AF are not anticoagulated. Language barriers and poor health literacy have previously been associated with decreased patient medication adherence. The association between language barriers and initiation of anticoagulation therapy for AF is uncertain. Aims: The aims of this study were to determine whether demographic factors, including non‐English primary language, were (1) associated with not being initiated on anticoagulation for known AF prior to admission with stroke, and (2) associated with non‐adherence to anticoagulation in the setting of known AF prior to admission with stroke. Methods: A multicentre retrospective cohort study was conducted for consecutive individuals admitted to the three South Australian tertiary hospitals with stroke units over a 5‐year period. Results: There were 6829 individuals admitted with stroke. These cases included 5835 ischaemic stroke patients, 1333 of whom had pre‐existing AF. Only 40.0% presenting with ischaemic stroke in the setting of known pre‐existing AF were anticoagulated. When controlling for demographics, socioeconomic status and past medical history (including the components of the CHADS2VASC score and anticoagulation contraindications), having a primary language other than English was associated with a lower likelihood of having been commenced on anticoagulant for known pre‐stroke AF (odds ratio: 0.52, 95% confidence interval: 0.36–0.77, P = 0.001), but was not associated with a differing likelihood of anticoagulation adherence. Conclusions: A significant proportion of patients with stroke have pre‐existing unanticoagulated AF; these rates are substantially higher if the primary language is other than English. Targeted research and interventions to minimise evidence‐treatment gaps in this cohort may significantly reduce stroke burden. [ABSTRACT FROM AUTHOR]

Direct-to-consumer (D2C) wearables are becoming increasingly popular in cardiovascular health management because of their affordability and capability to capture diverse health data. Wearables may enable continuous health care provider-patient partnerships and reduce the volume of episodic clinic-based care (thereby reducing health care costs). However, challenges arise from the unregulated use of these devices, including questionable data reliability, potential misinterpretation of information, unintended psychological impacts, and an influx of clinically nonactionable data that may overburden the health care system. Further, these technologies could exacerbate, rather than mitigate, health disparities. Experience with wearables in atrial fibrillation underscores these challenges. The prevalent use of D2C wearables necessitates a collaborative approach among stakeholders to ensure effective integration into cardiovascular care. Wearables are heralding innovative disease screening, diagnosis, and management paradigms, expanding therapeutic avenues, and anchoring personalized medicine. [Display omitted] • D2C wearables offer affordable and accessible health care data that may facilitate management of cardiovascular disorders. • There are concerns about accuracy, value, unintended psychological responses, and data overload from wearable-derived data. • Wearables promise novel paradigms for disease screening, diagnosis, and management, thereby setting a foundation for personalized medicine. [ABSTRACT FROM AUTHOR]

Background: Traditional methods for the quantification of OSA severity may not encapsulate potential relationships between hypoxemia in OSA and cardiovascular risk.Research Question: Do novel nocturnal oxygen saturation (Spo2) metrics have prognostic value in patients with OSA and high cardiovascular event risk?Study Design and Methods: We conducted post hoc analyses of the Sleep Apnea Cardiovascular Endpoints (SAVE) trial. In 2687 individuals, Cox proportional hazards models that were stratified for treatment allocation were used to determine the associations between clinical characteristics, pulse oximetry-derived metrics that were designed to quantify sustained and episodic features of hypoxemia, and cardiovascular outcomes. Metrics included oxygen desaturation index, time <90% Spo2, average Spo2 for the entire recording (mean Spo2), average Spo2 during desaturation events (desaturation Spo2), average baseline Spo2 interpolated across episodic desaturation events (baseline Spo2), episodic desaturation event duration and desaturation/resaturation-time ratio, and mean and SD of pulse rate.Results: Neither apnea-hypopnea index, oxygen desaturation index, nor any of the novel Spo2 metrics were associated with the primary SAVE composite cardiovascular outcome. Mean and baseline Spo2 were associated with heart failure (hazard ratio [HR], 0.81; 95% CI, 0.69-0.95; P = .009; and HR, 0.78; 95% CI, 0.67-0.90; P = .001, respectively) and myocardial infarction (HR, 0.86; 95% CI, 0.77-0.95; P = .003; and HR, 0.81; 95% CI, 0.73-0.90; P < .001, respectively). Desaturation duration and desaturation/resaturation time ratio, with established risk factors, predicted future heart failure (area under the curve, 0.86; 95% CI, 0.79-0.93).Interpretation: Apnea-hypopnea index and oxygen desaturation index were not associated with cardiovascular outcomes. In contrast, the pattern of oxygen desaturation was associated with heart failure and myocardial infarction. However, concomitant risk factors remained the predominant determinants for secondary cardiovascular events and thus deserve the most intensive management. [ABSTRACT FROM AUTHOR]

Background: Obesity is associated with an increased risk of developing recurrent atrial fibrillation (AF) after catheter ablation (CA). However, the current data on weight loss interventions show inconsistent results in preventing the recurrence of AF after CA. Methods: We conducted a systematic search in MEDLINE and EMBASE to identify studies that reported the outcome of recurrence of AF after CA in obese patients undergoing weight interventions. The subgroup analysis included: (1) Weight loss versus no weight loss, (2) >10% weight loss versus <10% weight loss, (3) <10% weight loss versus no weight loss, (4) Follow‐up <12 months, and (5) Follow‐up >12 months after CA. Mantel–Haenszel risk ratios with a 95% confidence interval (CI) were calculated using a random effects model and for heterogeneity, I2 statistics were reported. Results: A total of 10 studies (one randomized controlled trial and nine observational studies) comprising 1851 patients were included. The recurrence of AF was numerically reduced in the weight loss group (34.5%) versus no weight loss group (58.2%), but no statistically significant difference was observed (risk ratio [RR] = 0.76; 95% CI: 0.49–1.18, p =.22). However, there was a statistically significant reduction in recurrence of AF with weight loss versus no weight loss at follow‐up >12 months after CA (RR = 0.47; 95% CI: 0.32–0.68, p <.0001). At follow‐up >12 months after CA, both >10% weight loss versus <10% weight loss (RR = 0.49; 95% CI: 0.31–0.80, p =.004) and <10% weight loss versus no weight loss (RR = 0.39; 95% CI: 0.31–0.49, p <.00001) were associated with a statistically significant reduction in recurrent AF. Conclusion: In patients with AF undergoing CA, weight loss is associated with reducing recurrent AF at > 12 months after ablation and these benefits are consistently seen with both >10% and <10% weight loss. The benefits of weight loss in preventing recurrent AF after CA should be examined in larger studies with extended follow‐up duration. [ABSTRACT FROM AUTHOR]

The left atrium (LA) plays a critical role in receiving pulmonary venous return and modulating left ventricular (LV) filling. With the onset of exercise, LA function contributes to the augmentation in stroke volume. Due to the growing focus on atrial imaging, there is now evidence that structural remodeling and dysfunction of the LA is associated with adverse outcomes including incident cardiovascular disease. In patients with established disease, pathological changes in atrial structure and function are associated with exercise intolerance, increased hospital admissions and mortality, independent of left ventricular function. Exercise training is widely recommended in patients with cardiovascular disease to improve patient outcomes and maintain functional capacity. There are widely documented changes in LV function with exercise, yet less attention has been given to the LA. In this review, we first describe LA physiology at rest and during exercise, before exploring its association with cardiac disease outcomes including atrial fibrillation, heart failure, and stroke. The adaptation of the LA to short- and longer-term exercise training is evaluated through review of longitudinal studies of exercise training in healthy participants free of cardiovascular disease and athletes. We then consider the changes in LA structure and function among patients with established disease, where adverse atrial remodeling may be implicated in the disease process. Finally, we consider important future directions for assessment of atrial structure and function using novel imaging modalities, in response to acute and chronic exercise. [ABSTRACT FROM AUTHOR]