Smaller Left Atrial Size Research Articles

Severe aortic stenosis is associated with left atrial prothrombotic flow changes that persists despite successful aortic valve replacement

Abstract Background Severe aortic stenosis (AS) is associated with ischaemic stroke independently of atrial fibrillation (AF) or other causes. Even after aortic valve replacement (AVR), patients remain affected by up to 15% five-year rate of incident ischaemic strokes independently of AVR-related complications and with knowledge gaps in the underlying pathophysiology. Purpose To assess whether severe AS leads to prothrombotic left atrial (LA) flow changes with reduction of LA velocities and vorticity which do not normalise after AVR. Methods Seventy-seven participants without history of AF were recruited in this study: N=40 with severe AS (60% male; age 73 ±10 years, BMI 28 ±5 Kg/m2, median CHA2DS2VASc = 3) and N=37 controls with similar clinical risk profile (51% male; age 71 ±6 years, BMI 28 ±5 Kg/m2, median CHA2DS2VASc = 3). All participants underwent a cardiovascular magnetic resonance (CMR) scan to quantify left ventricular (LV) volumes, mass, and ejection fraction (LVEF), LV global longitudinal strain (GLS) as a sensitive marker of longitudinal dysfunction, LA maximum volume and emptying fraction (LAEF), LA blood flow peak velocity and vorticity by 4-dimensional flow CMR. Out of the 40 patients with severe AS, N=23 (58%) underwent a successful AVR and were followed-up with a repeat CMR scan at approximately 6 months after surgery. Results When compared to matched controls, patients with severe AS displayed significantly higher LV mass, smaller LA and LV volumes (i.e. concentric LV hypertrophy), significantly reduced GLS but higher (more hyperdynamic) LVEF (all p<0.05), as expected. LAEF (i.e. global LA function) was not significantly different from controls but despite this, severe AS was associated with slightly lower LA peak flow velocity (mean 0.25 vs. 0.28 m/sec respectively) and lower LA flow vorticity (mean 16.6 vs. 21.1 radians) compared to controls (both p<0.05). Successful AVR led to complete regression of LV hypertrophy (p<0.05) with LV mass that was no longer different from controls (p>0.05). Nevertheless, post-AVR patients displayed a persistent adverse morpho-functional phenotype characterised by persistently smaller LA and LV volumes, persistently hyperdynamic LV function with reduced GLS (all p<0.05), as well as adverse LA flow changes with significantly lower velocity (mean 0.24 vs 0.28 m/sec, p=0.003) and vorticity when compared to controls (17.1 vs 21.1 radians, p<0.001). Conclusions Patients with severe AS display adverse LA physiology and structure (prothrombotic LA flow characteristics in smaller LA size) and LV changes (smaller size with reduced longitudinal function and hyperdynamic function), which persist after successful AVR despite normalisation of the LV hypertrophy.Figure 1

Volume-pressure loop hemodynamic characterization of pulmonary hypertension

Abstract Background Pulmonary hypertension (PH) includes a wide spectrum of pathologies with different pathological bases and a variety of clinical scenarios in which right ventricular (RV)-pulmonary artery (PA) coupling has relevant prognostic implications. Currently, diagnosis and hemodynamic severity of PH is typically based on mean pulmonary arterial pressure (mPAP), pulmonary capillary wedge pressure (PCWP), and pulmonary vascular resistance (PVR). However, this conception does not take into consideration the evolution of these parameters throughout the cardiac cycle. We hypothesized that not only the magnitude but also the dynamics over time plays an important role in RV adaptation to pressure overload (i.e., constant fixed resistances throughout the cycle will have a different impact than a fluctuating resistances). Purpose To assess PA hemodynamic patterns throughout the cardiac cycle and their association with RV remodelling, by combining right heart catheterization (RHC) and cardiac magnetic resonance imaging (CMR) data. Methods 66 patients with PH (38 women, aged 63.59±14.70years, BMI 28.49±6.21 kg.m2) who underwent RHC in the supine position with a 7.5-FrSwan-Ganz catheter under fluoroscopic guidance (37 precapillary, 17 combined pre-postcapillary, 12 isolated postcapillary PH) and CMR with flow-encoded phase-contrast sequence were included. Pressure and flow tracings at the level of the main PA were integrated to obtain volume-pressure loops throughout the cardiac cycle. The resulting patterns based on morphology (Image 1) and slope (Pattern 1 mean slope 16,11% vs Pattern 2 mean slope 10,37%) were analysed and classified into 2 groups: Pattern 1 and Pattern 2. RV end-systolic (iRVESV) and end-diastolic volumes (iRVEDV), RV ejection fraction, RV mass and presence of late gadolinium enhancement (LGE) at the RV insertion points were compared between groups using parametric and non-parametric tests. Results Patients with Pattern 1 showed significantly higher mPAP (46.03±11.62 vs. 35.77±8.10 mmHg) and iPVR (746.22±584.54 vs 319.56±306.21 dynes.s.cm-5.m2) and lower PCWP (11.8±7.6 vs 17.7±7.2 mmHg). Precapillary PH patients more frequently presented a Pattern 1 (n=27; 77.1% vs 10; 32.3%). In addition, patients with Pattern 1 had higher RV volumes (iRVEDV= 105.45±34.62 ml/m2 vs 84.22±35.0 ml/m2, p=0,002; iRVESV 65.05±27.59 ml/m2 vs 44.63±25.09 ml/m2, p=0,001), poorer RV function (RVEF 39.81±11.33% vs 48.96±10.90%; p=0,001), larger RV mass (27.95±9.46 vs 23,44±7.46 g/m2, p=0,045) and smaller left atrial size (24.18±11.47 vs 34.06±19.15 cm2, p<0,001) than patients with Pattern 2. The quantification of LGE was also higher in Pattern 1 as compared with Pattern 2 (5.4±2.4% vs 3.0±2.3%, p<0.001). Conclusion Volume-pressure loops at the level of the main PA may differentiate patterns of PA hemodynamic fluctuations that have different impact on RV performance regardless the PH severity within the wide spectrum of PH.Volume-pressure loop patterns

PO-02-186 DIFFERENCES IN PATIENT CHARACTERISTICS AND ATRIAL FIBRILLATION ABLATION OUTCOMES BETWEEN HIGH VOLUME ACADEMIC AND COMMUNITY CENTERS- A COMPARISON FROM THE REAL-AF REGISTRY

It is unknown whether systematic differences exist in atrial fibrillation (AF) patient characteristics or ablation outcomes between high volume centers from the community or academia. We sought to compare the baseline characteristics, procedural parameters, and outcomes for radiofrequency (RF) ablation of paroxysmal AF performed at community and academic centers in the REAL-AF registry. REAL-AF is a prospective observational registry of high volume AF ablation operators with low fluoroscopy use from both academic and community practices. Using registry data, we compared baseline comorbidities, treatment choices, and arrhythmia free survival between community and academic centers, considering only paroxysmal atrial fibrillation. A total of 853 ablations were performed at community programs and 159 at academic programs. Patients enrolled in the community were more likely to have hypertension (62.8% vs 50.6%), obstructive sleep apnea (46.8% vs 34.6%), vascular disease (18.6% vs 5.1%), and a higher CHADSVASC score (2.5±1.53 vs 2.1±1.32 p<0.05 all - Table 1). Conversely, patients at academic centers had larger mean left atrial size (99.45±36.84 vs 83.75±24.12 cm3 p < 0.05). Patients at academic centers were more likely to receive oral anticoagulation pre-ablation (94.2% vs 85.5% p = 0.03). Procedurally, community centers in REAL-AF were more efficient with lower mean procedure time, RF ablation time and fluoroscopy use (p < 0.05 for all - Table 1). There was similar lesion set choices for the procedure. First pass isolation was achieved similarly between community and academic centers. Ablations in the community had a lower recurrence of -atrial fibrillation (16.2% vs 25.5% p = 0.02 ), however this difference was no longer significant on multivariate analysis accounting for confounders such as left atrial size. In the REAL AF registry, patients undergoing ablation of paroxysmal atrial fibrillation at community centers had more comorbidities but smaller left atrial size when compared to academic centers. High volume community providers were more efficient and used less fluoroscopy. Long-term outcomes were similar after accounting for differences in baseline characteristics.

Cardiac assessments of bottlenose dolphins (Tursiops truncatus) in the Northern Gulf of Mexico following exposure to Deepwater Horizon oil.

The Deepwater Horizon (DWH) oil spill profoundly impacted the health of bottlenose dolphins (Tursiops truncatus) in Barataria Bay, LA (BB). To comprehensively assess the cardiac health of dolphins living within the DWH oil spill footprint, techniques for in-water cardiac evaluation were refined with dolphins cared for by the U.S. Navy Marine Mammal Program in 2018 and applied to free-ranging bottlenose dolphins in BB (n = 34) and Sarasota Bay, Florida (SB) (n = 19), a non-oiled reference population. Cardiac auscultation detected systolic murmurs in the majority of dolphins from both sites (88% BB, 89% SB) and echocardiography showed most of the murmurs were innocent flow murmurs attributed to elevated blood flow velocity [1]. Telemetric six-lead electrocardiography detected arrhythmias in BB dolphins (43%) and SB dolphins (31%), all of which were considered low to moderate risk for adverse cardiac events. Echocardiography showed BB dolphins had thinner left ventricular walls, with significant differences in intraventricular septum thickness at the end of diastole (p = 0.002), and left ventricular posterior wall thickness at the end of diastole (p = 0.033). BB dolphins also had smaller left atrial size (p = 0.004), higher prevalence of tricuspid valve prolapse (p = 0.003), higher prevalence of tricuspid valve thickening (p = 0.033), and higher prevalence of aortic valve thickening (p = 0.008). Two dolphins in BB were diagnosed with pulmonary arterial hypertension based on Doppler echocardiography-derived estimates and supporting echocardiographic findings. Histopathology of dolphins who stranded within the DWH oil spill footprint showed a significantly higher prevalence of myocardial fibrosis (p = 0.003), regardless of age, compared to dolphins outside the oil spill footprint. In conclusion, there were substantial cardiac abnormalities identified in BB dolphins which may be related to DWH oil exposure, however, future work is needed to rule out other hypotheses and further elucidate the connection between oil exposure, pulmonary disease, and the observed cardiac abnormalities.

Clinical and molecular characterization of seven patients with Danon disease.

Danon disease is an X-linked glycogen storage disease characterized by skeletal myopathy, cardiomyopathy and intellectual impairment. It is caused by a loss-of-function mutation in the lysosome-associated membrane protein-2 (LAMP2) gene. In the present study, exon and boarding intron analysis of 96 cardio disease-associated genes was performed in 770 patients with hypertrophic cardiomyopathy (HCM) using second-generation sequencing. Next, the identified mutations were confirmed in family members of the patients and 300 healthy controls. Detailed clinical, electrocardiographic (ECG) and echocardiographic findings were recorded. A pathogenic mutation in LAMP2 was identified in 7 patients who phenotypically presented with HCM. A total of four patients had a fragmented QRS complex (fQRS) on surface ECG. In addition, two patients presented with ventricular preexcitation with a short PR interval. Compared with the patients with protein kinase AMP-activated non-catalytic subunit γ2 syndrome and Fabry disease, the 7 patients with Danon disease presented at an earlier age, had a smaller left atrial size, a thinner maximal left ventricular wall thickness and a lower probability of pacemaker implantation. Compared with 12 sex- and age-matched patients with sarcomere-protein mutations, the 4 patients with Danon disease had a lower left ventricular outflow tract gradient and worse diastolic function. The present study provided a comprehensive comparison of different pathologies presenting with HCM and reported on features of early-onset Danon disease, including the characteristic preexcitation and fQRS on ECG. This may provide valuable information that may be utilized for the early diagnosis and treatment of patients with Danon disease. The present study was registered as a clinical trial with ClinicalTrials.gov (Sep. 2, 2016; registry no. NCT02888132).

Relationship between dominant frequency, organization index, and left atrial size in patients with atrial fibrillation.

Frequency domain analysis is a methodology for quantifying the organization of atrial fibrillation (AF) pattern to understand the pathophysiology of the electrical mechanism. We aimed to investigate whether the dominant frequency (DF) and organization index (OI) can indicate left atrial (LA) dilatation in patients with AF. This observational, retrospective, single-center cohort study assessed 100 patients with persistent AF. The study population was divided into two groups based on an anterior-posterior LA dimension (LAD of 50 mm) measured by transthoracic echocardiography. The groups were one-to-one propensity score-matched. Frequency domain analysis was performed using signals at leads II and V1 on surface electrocardiogram to calculate the DF and OI. In all patients, the DF was shown to have an inverse relationship with LAD (R = -.369, p < .001 in lead II; R = -.330, p = .001 in lead V1), while the OI was directly associated with LAD (R = .234, p = .190 in lead II; R = .283, p = .004 in lead V1). However, no significant relationship between the signal amplitude and LAD was observed. Compared to patients with LAD ≤ 50 mm, those with LAD > 50 mm had a lower DF (5.057 ± 0.740 vs. 4.542 ± 0.898, p = .002) and higher OI (0.261 ± 0.104 vs. 0.322 ± 0.116, p = .007) in lead V1. These findings were consistent with those found in lead II. Patients with persistent AF and a larger LA size had a significantly higher OI and lower DF than those with a smaller LA size. Atrial electrical properties of structural remodeling are associated with increased organization of atrial signals.

P430Antiarrhythmic drug therapy in Russian patients undergoing atrial fibrillation ablation: a sub-analysis of the ESC-EHRA EORP registry

Abstract OnBehalf EHRA-ESC EORP AFA LT registry Introduction Despite the effectiveness of atrial fibrillation (AF) catheter ablation (CA), antiarrhythmic therapy (AAT) remains an important part of the complex treatment. Purpose To analyze AAT dynamics in Russian patients undergoing AF ablation, and to reveal potential factors associated with ongoing AAT in patients without arrhythmia recurrence. Methods The ESC-EHRA AF ablation registry was conducted in 2012-2016 in EHRA countries. The current analysis included 476 patients (57.1 male; 57.1 ± 8.7 years) who underwent AF ablation in 13 Russian clinics. AAT before, during and at 12-month follow-up (12-FU) was assessed. At baseline, paroxysmal AF was present in 320 (67.2%) patients, persistent AF - in 94 (19.7%), long-standing persistent AF- in 53 (11,1%), in 9 (1.9%) AF type was unknown. Hypertension (H) was present in 355 (74.6%) patients; congestive heart failure (CHF) (NYHA≥2) in 184 (38.7%) patients; coronary artery disease (CAD) in 132 (27.7%) patients. The CA was the first in 396 (83.2%) cases, redo ablation was performed in 80 (16.8%) cases. AF recurrences were registered according to local clinical practice. Any atrial tachyarrhythmia &amp;gt;30s was considered as a recurrence. Results A three-month FU (3-FU) visit was performed in 476 (100%) patients, 12-FU - in 390 (81.9%). Prior to PV isolation 439 (92.2%) patients received AAT, while after ablation there was an increase in the number of patients on AAT - 459 (96.4%). The highest number of patients on AAT was detected at 3-FU - 463 (97.3%). During 12 months at least one episode of arrhythmia recurrence was documented in 203 (52.1%) patients, and 370 (94.8%) patients were on AAT at the 12-month visit. After the 12-month visit 307 (78.7%) patients continued to receive AAT, and in 187 (47.9%) of them there was no arrhythmia recurrence after the index ablation. Five (2.7%) of these patients continued a Ic class AAT drug, 35 (18.7%) patients - class III, 129 (69.0%) patients - β-blockers (BB) and 18 (9.6%) patients - calcium channel blockers (CCB). All 187 patients had co-morbidities (75.4% - H; 41.7% - CHF (NYHA≥2; 31.6% - CAD). There were no statistically significant predictors of AAT use in patients without arrhythmia reccurence. According to the univariant regression analysis, the use of AAT III class (mainly-sotalol) at 12 months had a small but statistically significant negative association with left atrial size enlargement (OR = 0.917; 0.860-0.997); class III AAT was negatevely associated with BB therapy (OR = 0.057; 0.016-0.198); CCB therapy was associated with an older age (OR = 1.073; 1.053-1.151). Conclusions About one-half of patients without apparent arrhythmia recurrence following AF ablation do receive AAT. There were no clinical or procedure-related factors associated with AAT after effective AF ablation. Paradoxically, patients with a smaller left atrial size and without arrhythmia recurrence had more chances to receive class III AAT, what requires further analysis.

Which patients with atrial fibrillation undergo an ablation procedure today in Europe? A report from the ESC-EHRA-EORP Atrial Fibrillation Ablation Long-Term and Atrial Fibrillation General Pilot Registries.

Rhythm control management in patients with atrial fibrillation (AF) may be unequal across Europe. The aim of this study was to investigate how selective the patient cohort referred for AF ablation is, as compared to the general AF population in Europe, and to describe the governing mechanisms for such selection. Descriptive comparative statistical analyses of the baseline characteristics were performed between the cohorts of Atrial Fibrillation Ablation Long-Term (ESC EORP AFA-LT) registry, designed to provide a picture of contemporary real-world AF ablation, and the AF population from the AF-General (ESC EORP AF-Gen) pilot registry. Data collection was performed using a web-based system. In the AFA and in the Atrial Fibrillation General (AFG) pilot registries, 3593 and 3049 patients were enrolled, respectively. Patients who underwent AF ablation were younger, more commonly male, and had significantly less comorbidities. Atrial Fibrillation Ablation patients often presented without comorbidities, resulting in a lower risk of stroke (CHA2DS2-VASc ≥5: 2.9% vs. 24.5%, all P < 0.001) and bleeding (HAS-BLED ≥2: 8.5% vs. 40.5%, P < 0.001) but with European Heart Rhythm Association (EHRA) scores >1 and more prevalent AF-related symptoms such as palpitations, fatigue, and weakness (all P < 0.001) as compared to the general AF patients. Atrial Fibrillation Ablation patients were significantly more often male, had higher left ventricular ejection fraction (59.5% vs. 52.4%) and smaller left atrial size on echocardiogram (P < 0.001 each). The comparison of the patient cohorts in the AFA and AFG registries showed that AF ablation in European clinical practice is mostly performed in relatively young, symptomatic and relatively healthy patients.

P341Which patients with atrial fibrillation undergo an ablation procedure today in Europe? A report from the ESC-EHRA-EURObservational Research Programme

Abstract Aims Great heterogeneity in rhythm control management of patients with atrial fibrillation (AF) has been described. The aim of this study was to investigate how selective the patient cohort referred for AF ablation is, as compared to the general AF population in Europe, and to describe the governing mechanisms for such selection. Methods Descriptive comparative statistical analyses of the baseline characteristics were performed between the cohorts of Atrial Fibrillation Ablation Long-Term (ESC-EORP EHRA AFA-LT) Registry, designed to provide a picture of contemporary real-world AF ablation, and the AF population from the AF-General (ESC-EORP EHRA AF-Gen) PilotRegistry. Data collection was performed using a web-based system. Results In the AFA and in the AFG pilot registries 3593 and 3049 patients were enrolled, respectively. Patients who underwent AF ablation were younger,more commonly male, and had significantly less co-morbidities. Lone AF was predominant in AFA patients who were at lower risk of stroke (CHA2DS2-VASc &gt;5: 2.9% vs. 24.5%, all P&lt;0.001) and bleeding (HAS-BLED ≥2: 8.5% vs. 40.5%, P&lt;0.001) but with EHRA scores &gt;1 and more prevalentAF-related symptoms such as palpitations, fatigue and weakness (all p&lt;0.001)as compared to the general AF patients. AFA patients were significantly more often male, had higher LV ejection fraction (59.5% vs. 52.4%) and smaller left atrial size on echocardiogram (P&lt;0.001 each). Conclusions The comparison of the patient chorts in the AFA and AFG registries showed that AF ablation in European clinical practice is mostly performed in relatively young, symptomatic and otherwise relatively healthy patients. Acknowledgement/Funding Abbott Vascular Int.; Amgen Cardiovascular, AstraZeneca, Bayer, Boehringer Ingelheim, Boston Scientific, Bristol Myers Squibb and Pfizer Alliance

P wave indices, heart rate variability and anthropometry in a healthy South Asian population

BackgroundSouth Asians have a low prevalence of atrial fibrillation (AF) in comparison with White Europeans despite a higher burden of hypertension, diabetes mellitus and coronary artery disease. The reason for this disparity is unclear but may relate to electrophysiological or structural differences within the atria or variations in autonomic function. We aimed to assess these areas using a range of non-invasive cardiac investigations.MethodsA prospective cohort study was performed on 200 South Asian and 200 Caucasian healthy volunteers aged 18–40 years. All subjects underwent electrocardiography (ECG), echocardiography and anthropometric measurements. Eighty subjects in each cohort underwent 24 hour ambulatory ECG and fifty subjects in each cohort underwent exercise testing.ResultsCompared with White Europeans, South Asians were of a smaller height with lower lean body mass and smaller left atrial size. They had reduced P wave dispersion and P wave terminal force in lead V1. South Asians had a lower burden of supraventricular ectopy. They had a higher mean heart rate and South Asian males had lower heart rate variability, suggestive of sympathetic predominance. Exercise capacity was lower in South Asians.ConclusionsSouth Asians have differences in left atrial size, P wave indices, burden of supraventricular ectopy, heart rate, heart rate variability and anthropometric measurements. These differences may relate to variations in atrial morphology, atrial electrophysiology and autonomic function and might help to explain why South Asians are less susceptible to developing AF.

Abstract WP265: Racial Differences in Left Atrial Size Among Patients With Ischemic Stroke

Introduction: Blacks in the U.S. face twice the risk of ischemic stroke as whites, and this disparity is not fully explained by established stroke risk factors. Although atrial fibrillation (AF) is a major risk factor for stroke, blacks are less often diagnosed with AF than whites. It is unclear whether this paradox exists because AF is less thoroughly ascertained in blacks compared to whites or because blacks have less predisposing substrate and thus a truly lower risk of AF. Hypothesis: Based on our prior work, we hypothesized that black patients with ischemic stroke less often have left atrial enlargement, a major predisposing factor for AF. Methods: We compared left atrial size in black versus white patients in the Greater Cincinnati/Northern Kentucky Stroke Study, a study of racial disparities in stroke incidence in a nationally representative population of 1.3 million. We obtained reports of echocardiograms performed for stroke evaluation among patients in the 2010 and 2015 study periods. Patients with known AF or atrial flutter were excluded. Investigators blinded to patients’ characteristics abstracted left atrial diameter from echocardiogram reports. Linear regression was used to examine the association between race and left atrial diameter after adjustment for demographics, body mass index, and comorbidities. Results: Among 2,980 cases of ischemic stroke without AF, the median age was 66 years, 52% were female, and 30% were black. The overall mean left atrial diameter was 3.65 (±0.69) cm. Despite a higher burden of vascular risk factors and comorbidities, blacks had significantly smaller left atrial diameters (mean difference, -0.10 cm; 95% CI, -0.04 to -0.17 cm). This difference persisted after adjustment for demographics, comorbidities, and body mass index (adjusted mean difference, -0.15 cm; 95% CI, -0.09 to -0.21 cm). Conclusions: In a population-based sample, we found that black patients with ischemic stroke had smaller left atrial size than white patients. Our results suggest that the paradox of greater stroke risk but lower AF risk in blacks compared with whites at least partly stems from a lesser degree of AF substrate in blacks.

Left atrial size and function in a South Asian population and their potential influence on the risk of atrial fibrillation.

South Asians have a low prevalence of atrial fibrillation (AF) compared with Caucasians despite having a higher prevalence of conventional risk factors for the arrhythmia. The reason for this disparity is uncertain but may be due to ethnic differences in atrial morphology. This study examines the association between ethnicity and left atrial (LA) size and function in South Asian and Caucasian subjects using the reference technique of cardiovascular magnetic resonance imaging (MRI). South Asians have smaller LA size and therefore increased LA function. Retrospective case-control study of 60 South Asian and 60 Caucasian patients who had undergone a clinically indicated MRI between April 2010 and October 2017 and had been found to have a structurally normal heart. LA and left ventricular (LV) volume and function were assessed and compared between the ethnicities. In comparison with Caucasians, South Asians had significantly lower minimum (27.7 ± 11.1 mL vs 34.9 ± 12.3 mL, P = 0.002) and maximum LA volumes (64.7 ± 21.1 mL vs 80.9 ± 22.5 mL, P < 0.001), lower LV end-diastolic volume (P < 0.001), lower LV stroke volume (P < 0.001), and lower LV mass (P = 0.022) and these values remained significant after correcting for body surface area. Further analysis revealed that LA volume was independently associated with South Asian ethnicity. There was no difference in LA function between the ethnic groups. South Asians have reduced LA volumes and a proportionally smaller heart size in comparison to Caucasians. Smaller LA size may protect against the development of AF by reducing the risk of reentrant circuit formation and atrial fibrosis development.

Left-Sided Surgical Ablation for Patients With Atrial Fibrillation Who Are Undergoing Concomitant Cardiac Surgical Procedures

Growing evidence indicates the effectiveness of surgical ablation confined to the left atrium, especially with short duration of atrial fibrillation (AF) and smaller left atrial (LA) size. This study examined rhythm status and predictors of failure in this group of patients. Of 800 patients who underwent concomitant surgical ablation (2005 to 2015), 110 had LA-only ablation. Rhythm status was defined according to Heart Rhythm Society guidelines: sinus rhythm (SR) without class I/III antiarrhythmic drugs (AADs). Multivariate analyses examined predictors for SR without AADs. Predictors of failure were also stratified as age 75 years or older, LA size 5 cm or larger, AF duration 5 years or more, and nonparoxysmal AF type for secondary analyses. Mean age was 70.7 ± 9.4 years, mean EuroSCORE II (European System for Cardiac Operative Risk Evaluation) was 4.7 ± 4.3%, mean LA size was 4.4 ± 0.8 cm, median (interquartile range) AF duration was 3.5 months (range, 0.4 to 21 months), 26% of patients were female, 59% had coronary artery bypass graft procedures, 36% had aortic valve procedures, and 25% had mitral valve procedures. SR without AADs at 6, 12, and 24 months was 82% (79 of 96), 87% (78 of 90), and 79% (61 of 77), respectively. The only independent predictor of SR without AADs at 6 months was smaller LA size (odds ratio, 0.35; p= 0.014). Return to SR without AADs at 6, 12, and 24 months was as follows: 92%, 93%, and 91%, respectively, for patients with no traditional predictors of failure (n= 32); 88%, 90%, and 77%, respectively, for one predictor (n= 47); and 66%, 76%, and 70% for two or more predictors (n= 31). LA-only ablation yielded acceptable success rates, primarily in patients with shorter AF duration and smaller LA. However, success was reduced in patients with traditional predictors of failure. Well-designed studies with standardized lesion sets and ablation tools are required to determine whether full Cox maze yields better outcomes in patients with more advanced AF.

Abstract 17161: Reduced Ventilatory Function and Gas Exchange are Associated With Cardiac Remodeling and Changes in Systolic and Diastolic Function in the Community

Introduction: Chronic lung disease and heart failure have been reported to be associated, but the pathophysiologic relations between cardiac and pulmonary structure and function in the community are not well understood. We evaluated cross-sectional associations between measures of pulmonary function and echocardiographic traits related to cardiac remodeling and systolic and diastolic function in a large, community-based sample. Hypothesis: We hypothesized that lower ventilatory function and diffusion capacity would be associated with adverse cardiac remodeling and reduced left ventricular (LV) systolic and diastolic function. Methods: Forced expiratory volume in 1 second (FEV1), single-breath carbon monoxide diffusion capacity (DLCO), and comprehensive echocardiographic measures were obtained in approximately 2500 participants (mean age 67±9 years; 55% women) attending the 8 th Framingham Offspring examination cycle. Results: Using multivariable-adjusted linear regression models, we observed lower DLCO to be associated with lower fractional shortening, relatively higher early LV filling (E/A ratio), greater LV filling pressures (E/e’ ratio), and smaller right ventricular (RV) size ( Table) . Similarly, lower FEV1 was associated with smaller left atrial size, relatively higher early LV filling (E/A ratio), smaller RV size, and smaller right atrial area ( Table ). Conclusions: Lower ventilatory function and diffusion capacity are associated with smaller cardiac chamber dimensions, worse LV systolic function, and changes in measures of LV diastolic filling. The mechanisms responsible for these relations require further investigation, but these associations provide evidence for a pathophysiologic association between chronic lung disease and abnormalities in cardiac structure and function in the community.

Response to ECG, June 2015

Growing evidence indicates the effectiveness of surgical ablation confined to the left atrium, especially with short duration of atrial fibrillation (AF) and smaller left atrial (LA) size. This study examined rhythm status and predictors of failure in this group of patients.Of 800 patients who underwent concomitant surgical ablation (2005 to 2015), 110 had LA-only ablation. Rhythm status was defined according to Heart Rhythm Society guidelines: sinus rhythm (SR) without class I/III antiarrhythmic drugs (AADs). Multivariate analyses examined predictors for SR without AADs. Predictors of failure were also stratified as age 75 years or older, LA size 5 cm or larger, AF duration 5 years or more, and nonparoxysmal AF type for secondary analyses.Mean age was 70.7 ± 9.4 years, mean EuroSCORE II (European System for Cardiac Operative Risk Evaluation) was 4.7 ± 4.3%, mean LA size was 4.4 ± 0.8 cm, median (interquartile range) AF duration was 3.5 months (range, 0.4 to 21 months), 26% of patients were female, 59% had coronary artery bypass graft procedures, 36% had aortic valve procedures, and 25% had mitral valve procedures. SR without AADs at 6, 12, and 24 months was 82% (79 of 96), 87% (78 of 90), and 79% (61 of 77), respectively. The only independent predictor of SR without AADs at 6 months was smaller LA size (odds ratio, 0.35; p = 0.014). Return to SR without AADs at 6, 12, and 24 months was as follows: 92%, 93%, and 91%, respectively, for patients with no traditional predictors of failure (n = 32); 88%, 90%, and 77%, respectively, for one predictor (n = 47); and 66%, 76%, and 70% for two or more predictors (n = 31).LA-only ablation yielded acceptable success rates, primarily in patients with shorter AF duration and smaller LA. However, success was reduced in patients with traditional predictors of failure. Well-designed studies with standardized lesion sets and ablation tools are required to determine whether full Cox maze yields better outcomes in patients with more advanced AF.

The relation of red blood cell fatty acids with vascular stiffness, cardiac structure and left ventricular function: the Framingham Heart Study.

Polyunsaturated fatty acids have been associated with beneficial influences on cardiovascular health. However, the underlying mechanisms are not clear, and data on the relations of polyunsaturated fatty acids to subclinical disease measures such as vascular stiffness and cardiac function are sparse and inconclusive. In a large community-based cohort, we examined the relations of omega-3 and other fatty acids to a comprehensive panel of vascular function measures (assessing microvascular function and large artery stiffness), cardiac structure and left ventricular function. Red blood cell (RBC) membrane fatty acid composition, a measure of long-term fatty acid intake, was assessed in participants of the Framingham Offspring Study and Omni cohorts and related to tonometry-derived measures of vascular stiffness and to a panel of echocardiographic traits using partial correlations. Up to n=3055 individuals (56% women, mean age 66 years) were available for analyses. In age- and sex-adjusted models, higher RBC omega-3 content was moderately associated (p≤0.002) with several measures of vascular stiffness and function in a protective direction. However, after multivariable adjustment, only an association of higher RBC omega-3 content with lower carotid-femoral pulse wave velocity (a measure of aortic stiffness) remained significant (r = -0.06, p=0.002). In secondary analyses, higher linoleic acid, the major nutritional omega-6 fatty acid, was associated with smaller left atrial size, even after multivariable adjustment (r = -0.064, p<0.001). In conclusion, in our cross-sectional community-based study, we found several associations consistent with the notion of protective effects of omega-3 and linoleic acid. The clinical significance of these modest associations remains to be elucidated.

Factors predicting an arrhythmogenic superior vena cava in atrial fibrillation ablation: insight into the mechanism.

The superior vena cava (SVC) is an infrequent but important source of atrial fibrillation (AF), but is not always easy to identify. This study aimed to identify predictors of an arrhythmogenic SVC (a-SVC) in patients undergoing AF ablation. Eight hundred thirty-six consecutive patients undergoing AF ablation were analyzed. All patients underwent pulmonary vein antrum isolation during the index procedure. An a-SVC, defined as SVC-triggered AF and an SVC associated with the maintenance of AF, was evaluated by mapping catheters throughout the procedure. An a-SVC was identified in 44 patients (5.3%) during a total of 1063 procedures. Patients with an a-SVC were younger, less obese, and had a smaller left atrial (LA) size and more paroxysmal AF than those without an a-SVC. The presence of structural heart disease and hypertension was lower, and the coexistence of spontaneous common atrial flutter (AFL) before or during the index procedure was higher in those with an a-SVC than in those without. A multiple logistic regression analysis revealed that the LA size (odds ratio 0.93; 95% confidence interval 0.88-0.99; P = .038) and coexistence of spontaneous common AFL (odds ratio 2.01; 95% confidence interval 1.00-4.02; P = .048) were independent predictors identifying an a-SVC. Although 19 patients (43.2%) required repeat procedures, 39 (88.6%) were free from any atrial tachyarrhythmias without antiarrhythmic drugs at a median of 16.5 months (25th-75th percentiles 9.0-27.0 months) after a mean of 1.5 ± 0.7 procedures. A smaller LA size and coexistence of spontaneous common AFL were independent predictors of an a-SVC in the context of AF ablation.

Rhythm course over 5 years following surgical ablation for atrial fibrillation†

Reporting methods for surgical ablation (SA) of atrial fibrillation (AF) were standardized by the Heart Rhythm Society Guidelines, stating that results should be reported only for the first 2 years following SA. The purpose of this study was to assess the outcome of SA over 5 years and determine predictors for success over that period. Data were collected prospectively for all SA (n=787). Rhythm was verified by electrocardiogram and Holter monitoring at 3, 6, 9, 12, 18 and 24 months and yearly thereafter. Patients with rhythm status available at 2 and 5 years were included in the main analyses (n=137). Multivariate logistic regression was used for predictors of normal sinus rhythm (NSR). Receiver operating curves compared 2- and 5-year predicted probability against observed rhythm status by year. Return to NSR at 2 years was 88% (80% off antiarrhythmic drugs) and at 5 years was 85% (71% off antiarrhythmic drugs). The majority of patients (64%) had stable NSR over 5 years. The only predictor for 2-year NSR was smaller left atrial size (odds ratio [OR]=0.40, P=0.044). Predictors for 5-year NSR were smaller left atrial size (OR=0.28, P=0.002), age (OR=0.91, P=0.031) and length of hospital stay (OR=0.85, P=0.026). This study demonstrated stable results of SA for AF over time with somewhat different predictors for 2- and 5-year NSR in a group of patients with complete follow-up at both time points. Accurate models to determine predictors for success of SA more than 2 years after surgery are essential to better understand long-term outcome for patients with AF.

022 * RHYTHM COURSE OVER FIVE YEARS FOLLOWING SURGICAL ABLATION FOR ATRIAL FIBRILLATION

Objectives: Reporting methods for surgical ablation (SA) of atrial fibrillation (AF) were standardized by the Heart Rhythm Society guidelines, which state that results should be reported only for the first two years following SA. The purpose of this study was to assess stability of SA results over five years and determine predictors for success over that period. Methods: Data were collected prospectively for all SA (n = 754). Rhythm was verified by electrocardiogram and Holter at 3, 6, 9, 12, 18, and 24 months and yearly thereafter. Only patients with rhythm status available at five years were included in the analyses (n = 119). Multivariate logistic regression was used for predictors of sinus rhythm (NSR). ROC curves compared two-year predicted probability against observed rhythm status by year. Results: Return to NSR at two years was 85% (77% off antiarrythmic drugs [AAD]) and at five years was 84% (71% off AAD). Predictors for two-year NSR were shorter length of stay (OR = 0.84, P = 0.03), no peripheral vascular disease (OR = 225.7, P = 0.01), no pacemaker pre-surgery or perioperatively (OR = 17.0, P = 0.02) and smaller left atrial size (OR = 0.40, P = 0.08). Except for pacemakers, the same pattern of results was found for NSR at both two and five years. The majority of patients (63%) had stable NSR over five years. Area under the curve 0.91 at two years, 0.81 at four years and 0.73 at five years. Conclusions: This study demonstrated stable results of SA over time with similar predictors for two-year and 2+ to five-year NSR. Accurate models to determine predictors for success of SA more than two years after surgery are essential to better understand long-term outcome for patients with AF.

Prevalence, Characteristics, Mapping, and Catheter Ablation of Potential Rotors in Nonparoxysmal Atrial Fibrillation

Identification of critical atrial substrates in patients with nonparoxysmal atrial fibrillation (AF) failing to respond to pulmonary vein isolation is important. This study investigated the signal characteristics, substrate nature, and ablation results of rotors during AF. In total, 53 patients (age=55±8), 31 with persistent AF and 22 with long-lasting AF, underwent pulmonary vein isolation and substrate modification of complex fractionated atrial electrograms. Small-radius-reentrant rotors were identified from signal analyses of the dominant frequency and fractionation interval and nonlinear analyses (newly developed, beat-to-beat nonlinear measurement of the repetitiveness of the electrogram morphology>6 seconds). In 15% of the patients, activation maps demonstrated occurrences of rotor-like small-radius reentrant circuits (n=9; 1.1 per patient; cycle length=110±21 ms; diameter=11±6 mm) with fibrillation occurring outside these areas. Rotors were identified by conventional point-by-point mapping and signal analyses and were subsequently eradicated by catheter ablation in these patients. Persistent AF for <1 year, a smaller left atrial size, substrates with higher mean voltages and shorter total activation durations predicted a higher incidence of rotors (all P<0.05). In the multivariable model, areas of reentrant circuits exhibited a higher dominant frequency, kurtosis, and higher degree of a beat-to-beat electrogram similarity than areas without or outside the rotors (all P<0.05). Rotor-like re-entry with fibrillatory conduction was found in a limited number of patients with nonparoxysmal AF after pulmonary vein isolation. Those areas were characterized by rapid repetitive activity with a high degree of electrogram similarity.