Greater Left Atrial Size Research Articles

Predictive value of total atrial conduction time for developing cerebrovascular stroke in patients with sinus rhythm and normal left ventricular systolic function, a case-control study

Abstract Background Stroke is the second leading cause of death worldwide. Recently, atrial cardiopathy has become recognized as a substantial risk factor for cerebrovascular stroke. Greater LA size is linked to stroke in AF patients, but few data linking LA size to stroke in population with sinus rhythm. Purpose To investigate the value of total atrial conduction time (TACT) measured non-invasively by assessing PA-TDI duration as a predictor of stroke in patients who initially presented with sinus rhythm and have normal LV systolic function. Methods In our case-control study, we included 156 patients with acute ischemic stroke and 50 control subjects all presented in sinus rhythm and normal LV systolic function. All participants underwent echocardiography. The bi-plane modified Simpson's approach was used to determine the LV-EF. The left atrial (LA) diameter was measured also left atrial volume index (LAVI) was assessed. The PA-TDI interval was used to estimate the TACT. In the apical four-chamber view, the pulsed-wave tissue Doppler sample was positioned on the lateral and septal walls of the LA above the mitral annulus. The time between the onset of the P wave (lead II) and the peak of the A' wave was called the PA-TDI interval. Also, speckle tracking indices of LA strain were measured. Results LA volume index was larger in the stroke group (39.24±4 versus 33.6±2.8, p: 0.01), PA-TDI duration showed statistical highly significant difference between both groups (165.94±21.695 versus 99.4±22.960, p: <0.001). There were significantly impaired LAS parameters in the stroke group (LA reservoir, contraction & conduit strain, 22.7%, -6.6% & -16.1% versus 40%, -12%, and − 27% in the control group with P < 0.000). ROC curve showed the best cutoff point for LA volume index is >42.2 ml/m2 for prediction of stroke with area under the curve (AUC): 0.7, p value is 0.005. ROC curve showed the best cutoff point for PA-TDI is >155.5 ms. with AUC: 0.9, 90% sensitivity, 91% specificity, p value: <0.001. ROC curve showed that LA reservoir strain and LA stiffness can independently predict stroke at cut-off values of 30% & 24.5% respectively, P < 0.001. Multivariate logistic regression analysis showed that hypertension, LA volume index, LA stiffness and PA-TDI duration are independent predictors of stroke (p: < 0.05, < 0.05, < 0.01 and < 0.001 respectively). Conclusions The assessment of electromechanical asynchrony by measuring the PA-TDI duration may help to predict patients at risk for stroke. It is easy to measure without the need for special software like speckle tracking indices. We also advise patients who exceed the cutoff points of LA volume index and PA-TDI duration to receive antithrombotic therapy for better stroke prevention. Also we recommend adding PA-TDI to CHA2DS2-VASC-HSF score to assess stroke risk in patients with sinus rhythm and paroxysmal AF during their sinus rhythm intervals.

Identification of Clinical Drivers of Left Atrial Enlargement Through Genomics of Left Atrial Size.

Greater left atrial size is associated with a higher incidence of cardiovascular disease and mortality, but the full spectrum of diagnoses associated with left atrial enlargement in sex-stratified clinical populations is not well known. Our study sought to identify genetic risk mechanisms affecting left atrial diameter (LAD) in a clinical cohort. Using Vanderbilt deidentified electronic health record, we studied 6163 females and 5993 males of European ancestry who had at least 1 LAD measure and available genotyping. A sex-stratified polygenic score was constructed for LAD variation and tested for association against 1680 International Classification of Diseases code-based phenotypes. Two-sample univariable and multivariable Mendelian randomization approaches were used to assess etiologic relationships between candidate associations and LAD. A phenome-wide association study identified 25 International Classification of Diseases code-based diagnoses in females and 11 in males associated with a polygenic score of LAD (false discovery rate q<0.01), 5 of which were further evaluated by Mendelian randomization (waist circumference [WC], atrial fibrillation, heart failure, systolic blood pressure, and coronary artery disease). Sex-stratified differences in the genetic associations between risk factors and a polygenic score for LAD were observed (WC for females; heart failure, systolic blood pressure, atrial fibrillation, and WC for males). By multivariable Mendelian randomization, higher WC remained significantly associated with larger LAD in females, whereas coronary artery disease, WC, and atrial fibrillation remained significantly associated with larger LAD in males. In a clinical population, we identified, by genomic approaches, potential etiologic risk factors for larger LAD. Further studies are needed to confirm the extent to which these risk factors may be modified to prevent or reverse adverse left atrial remodeling and the extent to which sex modifies these risk factors.

Impact of a Center of Excellence in Confirming or Excluding a Diagnosis of Hypertrophic Cardiomyopathy

Tertiary hospitals with expertise in hypertrophic cardiomyopathy (HCM) are assuming a greater role in confirming and correcting HCM diagnoses at referring centers. The objectives were to establish the frequency of alternatediagnoses from referring centers and identify predictors of accuracy of an HCMdiagnosis from the referring centers.Imaging findings from echocardiography, cardiac computed tomography, and cardiac magnetic resonance imaging (CMR) in 210 patients referred to an HCM Center of Excellence between September 2020 and October 2022 were reviewed. Clinical and imaging characteristics from pre-referral studies were used to construct a model for predictors of ruling out HCM or confirming the diagnosis using machine learning methods (least absolute shrinkage and selection operator logistic regression). Alternative diagnoses were found in 38 of the 210 patients (18.1%) (median age 60years, 50% female). A total of 17 of the 38 patients (44.7%) underwent a new CMR after their initial visit, and 14 of 38 patients (36.8%) underwent review of a previous CMR. Increased left ventricular end-diastolic volume, indexed, greater septal thickness measurements, greater left atrial size, asymmetric hypertrophy on echocardiography, and the presence of an implantable cardioverter-defibrillator were associated with higher odds ratios for confirming a diagnosis of HCM, whereas increasing age and the presence of diabetes were more predictive of rejecting a diagnosis of HCM (area under the curve 0.902, p <0.0001).In conclusion, >1 in 6 patients with presumed HCM were found to have an alternate diagnosis after review at an HCM Center of Excellence, and both clinical findings and imaging parameters predicted an alternate diagnosis.

Serum fibrinogen-to-albumin ratio predicts new-onset atrial fibrillation risk during hospitalization in patients with acute myocardial infarction after percutaneous coronary intervention: a retrospective study

BackgroundNew-onset atrial fibrillation (NOAF) is a common adverse outcome of percutaneous coronary intervention (PCI) in patients with acute myocardial infarction (AMI) and is closely correlated with hospital stay and prognosis. In recent years, serum fibrinogen-to-albumin ratio (FAR), a novel biomarker for inflammation and thrombosis, has been used to predict the severity and prognosis of coronary artery disease. Our study aimed to investigate the relationship between FAR and NOAF during hospitalization after PCI in patients with AMI.MethodsWe retrospectively analyzed the incidence of NOAF during hospitalization and follow-up in 670 patients with AMI after PCI. Data were collected on patient age, sex, body mass index, medical history, current medication, heart failure, laboratory tests, culprit blood vessels, echocardiographic characteristics, and AMI type. The enrolled patients were divided into NOAF and non-NOAF groups. The baseline characteristics of patients in the two groups were compared, and the predictive correlation between FAR and NOAF was evaluated using logistic regression analysis and the receiver operating characteristic curve.ResultsFifty-three (7.9%) patients developed NOAF during hospitalization. The occurrence of NOAF was found to be independently associated with higher FAR besides older age, higher neutrophil count, greater left atrial size, worse Killip class upon admission, lower body mass index, lower platelet count, lower left ventricle ejection fraction, and target left circumflex artery disease. FAR exhibited a better predictive value for the occurrence of NOAF during hospitalization (area under the curve, 0.732; 95% confidence interval, 0.659–0.808).ConclusionsFAR is a robust tool for predicting NOAF risk during hospitalization in patients with AMI after PCI and has a better predictive value than serum fibrin and serum albumin levels alone.

Nutritional Status as a Risk Factor for New-Onset Atrial Fibrillation in Acute Myocardial Infarction.

Our study aimed to identify new-onset atrial fibrillation (NOAF) risk factors in acute myocardial infarction (AMI) patients after treatment with percutaneous coronary intervention (PCI) and investigate whether their nutritional status can be a predicting factor of NOAF. We analyzed 662 AMI patients after PCI for NOAF occurrence during follow-up hospitalization and divided them into an NOAF and non-NOAF group. The patients' nutritional status was assessed using the controlling nutritional status (CONUT) score and geriatric nutritional risk index (GNRI). The Kaplan‒Meier analysis was used to assess NOAF-free survival in varying degrees of malnutrition. Cox proportional hazards models were used to identify the risk factors for NOAF. Eighty-four (12.7%) patients developed NOAF during hospitalization. There was a statistically significant difference in the occurrence of NOAF among different categories of nutritional status. The CONUT score and GNRI classifications were independent predictors of NOAF. NOAF occurrence was associated with older age, higher uric acid levels, higher N-terminal pro-B-type natriuretic peptide levels, greater left atrial size, and worse Killip class upon admission. The nutritional status can affect NOAF occurrence in AMI patients after PCI. The CONUT score and GNRI are ideal tools for evaluating the nutritional status of AMI patients, with an excellent predictive effect on NOAF.

White Coat Hypertension: When Office Blood Pressure Impacts Cardiac Mechanics More Than Ambulatory. Is This Really So?

Hypertensive heart disease, characterized by left ventricular (LV) hypertrophy, left atrial enlargement, and LV dysfunction, represents a relatively advanced stage of hypertension-mediated organ damage (HMOD) typically associated with unrecognized or inadequately controlled systemic hypertension. However, a growing amount of evidence supports the view that subtle cardiac morphofunctional abnormalities such as LV concentric remodeling and mild impairment in LV relaxation can develop very early in the natural history of hypertension. Furthermore, an increased risk of initial cardiac HMOD has also been reported for long-held innocent conditions such as prehypertension and white coat hypertension (WCH). WCH is a common condition in which blood pressure (BP) measured in the medical environment is elevated while ­out-of-office BP (i.e., home and/or ambulatory BP [ABP]) is ­normal.1 The relationship between WCH and cardiac HMOD, an intermediate step linking hypertension with overt cardiovascular disease, has been investigated by numerous individual studies and their meta-analyses. Pooled data from 25 studies, including a total of 7.382 untreated individuals (2.493 true normotensives, 1.705 WCH, and 3.184 sustained hypertensives), showed that LV mass index (LVMI) gradually increased from normotensive, WCH, to sustained hypertensive patients. A meta-regression analysis restricted to WCH group documented a significant direct correlation between LVMI and office systolic BP (r = 0.42, P < 0.01); this was not the case for daytime systolic BP (r = 0.18, P = 0.17). Of note, the meta-analysis suggested that LV relaxation (in parallel with a greater left atrial size) but not LV ejection fraction (LVEF) was impaired in WCH.2

Differences in Left Atrial Size and Function and Supraventricular Ectopy Between Black and White Participants in the ARIC Study.

BackgroundBlack Americans have more atrial fibrillation risk factors but lower atrial fibrillation risk than White Americans. Left atrial (LA) enlargement and/or dysfunction, frequent atrial tachycardia (AT), and premature atrial contractions (PAC) are associated with increased atrial fibrillation risk. Racial differences in these factors may exist that could explain the difference in atrial fibrillation risk.Methods and ResultsWe included 2133 ARIC (Atherosclerosis Risk in Communities) study participants (aged 74±4.5 years[mean±SD], 59% women, 27% Black participants) who had echocardiograms in 2011 to 2013 and wore the Zio XT Patch (a 2‐week continuous heart monitor) in 2016 to 2017. Linear regression was used to analyze (1) differences in AT/day or PAC/hour between Black and White participants, (2) differences in LA measures between Black and White participants, and (3) racial differences in the association of LA measures with AT or PAC frequency. Compared with White participants, Black participants had a higher prevalence of cardiovascular risk factors and disease, lower AT frequency, greater LA size, and lower LA function. After multivariable adjustments, Black participants had 37% (95% CI, 24%–47%) fewer AT runs/day than White participants. No difference in PAC between races was noted. Greater LA size and reduced LA function are associated with more AT and PAC runs; however, no race interaction was present.ConclusionsDifferences in LA measures are unlikely to explain the difference in atrial fibrillation risk between Black and White individuals. Despite more cardiovascular risk factors and greater atrial remodeling, Black participants have lower AT frequency than White participants. Future research is needed to elucidate the protective mechanisms that confer resilience to atrial arrhythmias in Black individuals.

Abstract 14520: Differences in Left Atrial Size and Function and Supraventricular Arrhythmias Between Blacks and Whites in the Atherosclerosis Risk in Communities (ARIC) Study: Implications for AF Pathogenesis

Introduction: Black Americans have more atrial fibrillation (AF) risk factors but lower AF risk than whites. Left atrial (LA) enlargement, impaired LA function, frequent premature atrial contractions (PAC), and atrial tachycardia (AT) are risk factors for AF. Racial differences in LA size and function, PAC, or AT may exist that could explain the difference in AF risk. Hypothesis: Whites have higher PAC and AT frequency than blacks. Additionally, whites have larger LA size and lower LA function than blacks, which may contribute to the racial difference in AF. Methods: We included 1,623 ARIC participants free of AF who had 2D-echocardiograms at visit 5 (2011-2013) and wore a 2-week continuous heart monitor, the Zio ® XT Patch, at visit 6 (2016-2017). Weighted linear regression was used to analyze the association of race with LA size and function, as well as runs of AT per day and PAC per hour. Results: At visit 5, participants were 74 (4) years old, 58% were female, and 26% were black. AT runs were detected in 87% of blacks and 92% of whites, respectively (p=0.002). Among participants with &gt;0 runs of AT per day (n=1480), blacks had 48% (95% CI: 21%-66%) fewer runs of AT per day than whites after adjustment for cardiovascular (CV) risk factors † . There was no significant difference in PAC frequency between blacks and whites. After adjusting for age and sex, blacks had greater LA size and lower LA function than whites; these differences attenuated after adjusting for CV risk factors (Table). Conclusion: Blacks have greater age and sex-adjusted abnormality in LA size and function than whites, likely due to higher prevalence of CV risk factors. Yet, blacks have lower propensity for AT. More research is needed to elucidate the mechanisms underlying the resistance to atrial arrhythmogenesis in blacks despite greater adverse LA remodeling.

5029Obese hypertensive men have lower circulating proatrial natriuretic peptide concentrations despite greater left atrial size

5029Obese hypertensive men have lower circulating proatrial natriuretic peptide concentrations despite greater left atrial size

P4927Serum proatrial and B-type natriuretic peptide do not increase with higher systolic blood pressure in obese men despite evidence of greater left atrial size and higher left ventricular mass

P4927Serum proatrial and B-type natriuretic peptide do not increase with higher systolic blood pressure in obese men despite evidence of greater left atrial size and higher left ventricular mass

Association between Clinical and Doppler Echocardiographic Parameters with Sudden Death in Hemodialysis Patients.

Background:Sudden cardiac death (SCD) is the leading cause of death in maintenance hemodialysis (HD) patients, but there is little information about underlying risk factors.Objectives:Evaluate the association between clinical and echocardiographic variables with SCD on HD patients.Methods:Retrospective nested case-control study on chronic HD patients who were prospectively followed. The primary endpoint was SCD. Variables were compared by Student t test, Mann-Whitney or Chi-Square, and independent predictors of SCD were evidenced by multivariate logistic regression.Results:We followed 153 patients (50 ± 15 years, 58% men) for 23 ± 14 months and observed 35 deaths, 17 of which were SCD events. When compared to the control group (matched for gender, age, and body mass index) there were no differences regarding time on dialysis, traditional biochemical parameters, blood pressure, smoking, use of cardiovascular protective drugs, ejection fraction, left ventricular dimensions, and diastolic function indices. On the other hand, in the SCD group, we found a higher prevalence of previous heart failure, acute myocardial infarction and diabetes, greater left ventricular mass index, greater left atrial size and lower global myocardial performance. After multivariate logistic regression analysis, diabetes (OR = 2.6; CI = 1.3-7.5; p = 0.023) and left ventricular mass index ≥ 101 g/m2.7 (OR = 1.04; CI = 1.01-1.08; p = 0.028) showed independent association with SCD events.Conclusions:HD patients with diabetes mellitus and left ventricular hypertrophy appear to have the highest risk of SCD. Preventive and therapeutic strategies should be encouraged in addressing these risk factors to minimize the occurrence of SCD in HD patients.

Left ventricular hypertrophy after hypertensive pregnancy disorders

ObjectiveCardiac changes of hypertensive pregnancy include left ventricular hypertrophy (LVH) and diastolic dysfunction. These are thought to regress postpartum. We hypothesised that women with a history of hypertensive pregnancy would...

Early effects of transcatheter aortic valve implantation and aortic valve replacement on myocardial function and aortic valve hemodynamics: Insights from cardiovascular magnetic resonance imaging

There remains a paucity of mechanistic data on the effect of transcatheter aortic valve implantation (TAVI) on early left and right ventricular function and quantitative aortic valve regurgitation. We sought to assess and compare the early effects on myocardial function and aortic valve hemodynamics of TAVI and aortic valve replacement (AVR) using serial cardiovascular magnetic resonance (CMR) imaging and echocardiography. A prospective comparison study of 47 patients with severe aortic stenosis undergoing either TAVI (n = 26) or high-risk AVR (n = 21). CMR (for left ventricle/right ventricle function, left ventricular mass, left atrial volume, and aortic regurgitation) was carried out before the procedure and early postprocedure (<14 days). Groups were similar with respect to Society of Thoracic Surgeons score (TAVI, 7.7 vs AVR, 5.9; P = .11). Preoperative left ventricular (TAVI, 69% ± 13% vs AVR, 73% ± 10%; P = .10) and right ventricular (TAVI, 61% ± 11% vs AVR, 59% ± 8%; P = .5) ejection fractions were similar. Postoperative left ventricular ejection fraction was preserved in both groups. In contrast, decline in right ventricular ejection fraction was more significant in the TAVI group (61%-54% vs 59%-58%; P = .01). Postprocedure aortic regurgitant fraction was significantly greater in the TAVI group (16% vs 4%; P = .001), as was left atrial size (110 vs 84 mL; P = .02). Further analysis revealed a significant relationship between the increased aortic regurgitant fraction and greater left atrial size (P = .006), and a trend toward association between the decline in right ventricle dysfunction and increased postprocedure aortic regurgitation (P = .08). There was no significant difference in early left ventricular systolic function between techniques. Whereas right ventricle systolic function was preserved in the AVR group, it was significantly impaired early after TAVI, possibly reflecting a clinically important pathophysiologic consequence of paravalvular aortic regurgitation.

Left atrial size is independently associated with cognitive function

Left atrial (LA) diameter is easily attainable from echocardiograph and sensitive to underlying cardiovascular disease severity, although its association with neurocognitive outcomes is not well understood. Fifty older adults (64.50 ± 9.41 years), recruited from outpatient cardiology clinics and local papers who underwent magnetic resonance imaging, were administered the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS), and completed psychosocial self-report measures. LA diameter was quantified using echocardiogram. Hierarchical regression analyses revealed that greater LA size was independently associated with reduced performance on the following RBANS composites: language, delayed memory, and total index (p < 0.05 for all). Hierarchical regression analysis demonstrated no significant association between LA diameter and whole brain volume (p > 0.05). The current study suggests that greater LA size is associated with cognitive dysfunction in older adults and prospective studies are needed to validate these findings and elucidate underlying mechanisms.

The effectiveness of anti-arrhythmic drugs on recurrent atrial tachyarrhythmias after catheter ablation of atrial fibrillation

The prevalence of atrial fibrillation (AF) has increased substantially in the aging population. Drug therapies for maintaining sinus rhythm have been tried, but antiarrhythmic drug (AAD) responsiveness is relatively low in AF patients [1,2]. Guidelines recommend radiofrequency catheter ablation (RFCA) as a class I indication for drug resistant paroxyamal atrial fibrillation (PAF) and a class IIa indication for persistent AF (PeAF) [3]. Although the superiority of RFCA over AAD has been documented in clinical trials [4], the long-term recurrence rate is still substantial after AF catheter ablation [5]. There is little information on the efficacy of AAD in patients with recurrent AF after catheter ablation. Therefore, we evaluated the type and timing of recurrent atrial tachyarrhythmias after AF catheter ablation, to determine their responsiveness to AAD and the long-term clinical results of this treatment. This study included 397 consecutive patients with AAD refractory AF (77.1% males, 56.0±10.9 years old) who underwent RFCA. Among them, 69.5% of patients had PAFand 30.5% had PeAF. All patients initially underwent a circumferential pulmonary vein isolation (CPVI) and a bidirectionalblockof the cavo-tricuspid isthmus. InpatientswithPeAF,we conducted roof line, and posterior inferior line as a routine lesion set in all patients. We defined AF recurrence as any episode of AF or atrial tachycardia of at least 30 s in duration [6]. If any ECG documented an AF episode within the first three months of follow-up, the patient was diagnosed with an early recurrence (ER), and any AF recurrence thereafter was diagnosed as chronic recurrence (CR) [6] and AAD medications were prescribed. AAD was prescribed when AF recurrence was documented after RFCA. Oral flecainidewas given at a dose of 100– 200 mg per day (n=75, 18.9%), oral propafenone at 300–600 mg per day (n=1, 0.3%), oral pilsicainide at 150 mg per day (n=3, 0.8%), and oral amiodarone at an initial dose of 400 mg a day (n=103, 25.9%) for the first 2 weeks. The study protocol was approved by the Institutional ReviewBoardof YonseiUniversityHealthSystemand informed consents were obtained from patients. Of the total 397 patients, 130 patients (32.7%) experienced AF recurrence within 3 months after RFCA, and 98 patients (24.7%) experienced AF recurrence after the third month post-RFCA during the 16.1±5.0 months of follow-up. 60 patients (46.2%) out of 130 patients with ER experienced CR. Of the recurrent atrial tachyarrhythmias, 31.3% were atrial tachycardias (AT), and the remainder experienced AF. Patients with ER or CR had a greater left atrial size (p=0.001) or longer ablation time (pb0.001), and were more likely to be PeAF (p=0.003) than those who remained in sinus rhythm (Table 1). The use of additional ablation lines did not affect the incidences of ER or CR. Independent predictors for CR among the patients with ER were slower heart rate at recurrent presentation (odds ratio 0.984; 95% CI 0.971–0.998, p=0.029) and later timing of recurrencewithin 3 months post-RFCA (odds ratio 1.015; 95% CI 1.000–1.030, p=0.049). Within 2 weeks of AADprescription, 74.8% of the patientswith ER and 64.2% of CR converted to sinus rhythm without cardioversion. Sinus conversion rates of AT vs. AF (71.0% vs. 70.0%, p=0.891) and class IC AAD vs. amiodarone (69.6% vs. 71.8%, p=0.745) were not significantly different. The proportion of PeAF was significantly lower in AAD responders, who were converted to sinus rhythm within 2 weeks after AAD therapy (31.8%), than in non-responders (56.6%, p=0.003). Table 2 compares responders and non-responders in terms of class IC AAD and amiodarone. 34 (33.0%) out of 103 patients who took amiodarone were resistant to amiodarone before RFCA, and their sinus conversion rate was 55.9%. Among 79 patients who were prescribed class IC AAD, 63 patients (79.7%) took the same class IC AADs that were resistant before RFCA, and sinus conversion ratewas 69.8%. After pharmacologic cardioversion, sinus rhythmmaintenance rates with AAD were 55.3% with class IC and 52.2% with amiodarone during the 16.1±5.0 months of follow-up period

Influence of Race on Atrial Fibrillation After Cardiac Surgery

Despite having fewer risk factors for atrial fibrillation (AF), white patients have a greater prevalence of AF in the community than black patients, and a genetic basis has been postulated. However, it is unknown whether occurrence of new-onset AF after cardiac surgery is different in white versus black patients, and secondarily, other non-Caucasian patients. From 1995 through 2005, 20 282 white, 1323 black, and 1919 other non-Caucasian patients in sinus rhythm underwent coronary artery bypass grafting with or without valve surgery. To adjust for clinical and socioeconomic confounders, we performed propensity-adjusted analyses; 7093 white patients (35%) had postoperative AF, compared with 255 (22%) black patients and 550 (29%) other non-Caucasians (P<0.0001). Whites were older than black patients, had higher socioeconomic position, and greater left atrial size but were less likely to have hypertension or congestive heart failure. In 847 propensity-matched patient pairs, postoperative AF occurred more frequently in white than in black patients (odds ratio, 1.74; 95% confidence interval, 1.7-1.78). Other than higher occurrence of bradycardia requiring pacing and reintubation in white patients, occurrence of other postoperative complications, hospital mortality, and length of postoperative stay were similar. Age and valvular surgery were the strongest predictors of AF irrespective of race. White patients had a markedly higher risk of postoperative AF than black and other non-Caucasian patients. The cause for racial differences of arrhythmic risk is unknown, but a genetic predisposition is plausible. Our results have implications for risk stratification and mechanistic understanding of postoperative AF.

Relation of Obesity to Recurrence Rate and Burden of Atrial Fibrillation

Obesity is associated with new-onset atrial fibrillation (AF). However, the effect of obesity on AF recurrence or burden has not been studied. The aim of this study was to investigate the relation between AF recurrence, AF burden, and body mass index (BMI). A limited-access data set from the Atrial Fibrillation Follow-Up Investigation of Rhythm Management (AFFIRM) trial provided by the National Heart, Lung, and Blood Institute was used. Statistical analysis was done with a generalized linear mixed model. In 2,518 patients who had BMIs recorded, higher BMI was associated with a higher number of cardioversions (odds ratio [OR] 1.017, 95% confidence interval [CI] 1.005 to 1.029 for a BMI increase of 1 kg/m(2); OR 1.088, 95% CI 1.024 to 1.155 for a BMI increase of 5 kg/m(2); OR 1.183, 95% CI 1.049 to 1.334 for a BMI increase of 10 kg/m(2); p = 0.006 for each). Increased BMI was also associated with a higher likelihood of being in AF on follow-up (OR 1.020, 95% CI 1.002 to 1.038 per 1 kg/m(2) increased BMI, p = 0.0283; OR 1.104, 95% CI 1.011 to 1.205 per 5 kg/m(2) increased BMI, p = 0.0283; OR 1.218, 95% CI 1.021 to 1.452 per 10 kg/m(2) increased BMI, p = 0.0283). In a multivariate analysis, left atrial size but not BMI was an independent predictor of AF recurrence and AF burden. Because left atrial size was correlated with BMI, the effect of BMI on AF can be likely explained by greater left atrial size in subjects with higher BMIs. In conclusion, obesity is associated with a higher incidence of recurrence of AF and greater AF burden.

Alternative Energy Sources for Surgical Treatment of Atrial Fibrillation in Patients Undergoing Mitral Valve Surgery: Microwave Ablation vs Cryoablation

The study aim was to compare maze outcomes using microwave ablation or cryoablation in patients with mitral disease and atrial fibrillation (AF). Between 1999 and 2005, 340 patients underwent mitral valve surgery and concomitant maze procedure involving either microwave ablation (n=96, MW group) or cryoablation (n=244, Cryo group). Mean age at operation was 50.0±12.5 yr. Follow-up period was 46.1±28.2 months. The Cryo group showed a longer aortic clamping time than the MW group (P=0.005). There were no differences in operative mortality and morbidity rates. The unadjusted 5-yr AF free rate was 61.3±1.2% in the MW group and 79.9±3.2% in the Cryo group (P=0.089). After adjustment, the MW group only showed a tendency toward more frequent AF recurrence than the Cryo group (Hazard ration 1.66, 95% confidence interval 0.89 to 3.07). Multivariate analysis revealed that older patient age (P<0.001) and greater left atrial size (P<0.001) were independent risk factors for AF recurrence. Although the use of microwave ablation results in shorter aortic clamping time, it has a tendency toward more frequent late AF recurrence than with cryoablation.

Differences in Treadmill Exercise Tolerance Parameters Between Patients With Partial and Advanced Interatrial Depolarization Abnormality

Advanced interatrial block (aIAB) is considerably much less common than partial interatrial block (pIAB), occuring in <2% of the elderly hospitalized population. Less is, therefore, known of the true clinical burden of aIAB, particularly in relation to graded exercise. Therefore, 12 patients with aIAB and 30 patients with pIAB who performed a baseline exercise tolerance test and had a repeat test performed > or = 2 years later were included in the study. Exercise tolerance, echocardiographic findings, and major adverse cardiovascular events were compared. Left atrial size progressed at a significantly faster rate in those with aIAB. In addition, Duke Prognostic Treadmill scores were significantly lower on follow-up in those patients with aIAB. Overall, patients with aIAB had significantly greater left atrial size (48.3 +/- 9 vs 42.8 +/- 4 mm, p < 0.01) and significantly lower Duke Prognostic Treadmill scores than those with pIAB (-0.2 +/- 5 vs 4.1 +/- 4, p < 0.05). There were, however, no significant differences in the occurence of major adverse cardiovascular events. In conclusion, left atrial size progressed at a significantly faster rate but Duke Prognostic Treadmill scores were significantly lower in those with aIAB compared with patients with pIAB after > or = 2 years of follow-up. Further study is required to determine whether patients with aIAB require follow-up echocardiography and/or exercise tolerance tests for optimal risk stratification.

Relationship between left ventricular geometry and left atrial size and function in patients with systemic hypertension.

Arterial hypertension determines distinct adaptive left ventricular geometric responses, which may differently affect left ventricular function and left atrial performance. In this study, the effect of left ventricular geometry on left atrial size and function, and the relationship between left atrial size and left ventricular mass were assessed in 336 patients with systemic arterial hypertension who had undergone Doppler echocardiography. Patients were classified into concentric (110 patients with concentric left ventricular geometry defined as relative wall thickness > or = 0.44) and eccentric groups (226 patients with relative wall thickness < 0.44). Comparison to the latter, the former had greater left atrial size, left atrial ejection force, left ventricular mass and lower left ventricular midwall fractional shortening. Left ventricular concentric, rather than eccentric, geometry emerged by multivariate analysis as a factor independently associated with the highest degree of left atrial ejection force. Left atrial size was positively related to left ventricular mass in the whole population (r = 0.65, SEE = 6 ml, P < 0.00001). This relationship was maintained in the subgroups with concentric (r = 0.65, SEE = 6 ml, P < 0.00001) or eccentric geometry (r = 0.59, SEE = 6 ml, P < 0.00001). Our results indicate that the relationship of left ventricular geometry to both left atrial size and ejection force in hypertensive patients is relevant. Concentric left ventricular geometry is associated with greater left atrial size and ejection force than eccentric geometry, suggesting that increased left ventricular stiffness has a greater effect in stimulating left atrial performance than left ventricular end-systolic stress. The degree of left atrial enlargement similarly depends on left ventricular mass in patients with concentric and eccentric geometry.