Browsing by keyword "left atrium"
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Alcohol Consumption, Left Atrial Diameter, and Atrial FibrillationBACKGROUND: Alcohol consumption has been associated with atrial fibrillation (AF) in several epidemiologic studies, but the underlying mechanisms remain unknown. We sought to test the hypothesis that an atrial myopathy, manifested by echocardiographic left atrial enlargement, explains the association between chronic alcohol use and AF. METHODS AND RESULTS: We evaluated the relationship between cumulative alcohol consumption and risk of incident AF in 5220 Offspring and Original Framingham Heart Study participants (mean age 56.3 years, 54% women) with echocardiographic left atrial size measurements. The incidence of AF was 8.4 per 1000 person-years, with 1088 incident AF cases occurring over a median 6.0 years (25th-75th percentiles 4.0-8.7 years) of follow-up. After multivariable adjustment for potential confounders, every additional 10 g of alcohol per day (just under 1 drink per day) was associated with a 0.16 mm (95% CI, 0.10-0.21 mm) larger left atrial dimension. Also in multivariable adjusted analysis, every 10 g per day of alcohol consumed was associated with a 5% higher risk of developing new-onset AF (hazard ratio, 1.05; 95% CI, 1.01-1.09). An estimated 24% (95% CI, 8-75) of the association between alcohol and AF risk was explained by left atrial enlargement. CONCLUSIONS: Our study of a large, community-based sample identified alcohol consumption as a predictor of left atrial enlargement and subsequent incident AF. Left atrial enlargement may be an intermediate phenotype along the causal pathway linking long-term alcohol consumption to AF.
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Association of Left Atrial Function Index with Atrial Fibrillation and Cardiovascular Disease: The Framingham Offspring StudyBACKGROUND: Left atrial (LA) size, a marker of atrial structural remodeling, is associated with increased risk for atrial fibrillation (AF) and cardiovascular disease (CVD). LA function may also relate to AF and CVD, irrespective of LA structure. We tested the hypothesis that LA function index (LAFI), an echocardiographic index of LA structure and function, may better characterize adverse LA remodeling and predict incident AF and CVD than existing measures. METHODS AND RESULTS: In 1786 Framingham Offspring Study eighth examination participants (mean age, 66+/-9 years; 53% women), we related LA diameter and LAFI (derived from the LA emptying fraction, left ventricular outflow tract velocity time integral, and indexed maximal LA volume) to incidence of AF and CVD on follow-up. Over a median follow-up of 8.3 years (range, 7.5-9.1 years), 145 participants developed AF and 139 developed CVD. Mean LAFI was 34.5+/-12.7. In adjusted Cox regression models, lower LAFI was associated with higher risk of incident AF (hazard ratio=3.83, 95% confidence interval=2.23-6.59, lowest [Q1] compared with highest [Q4] LAFI quartile) and over 2-fold higher risk of incident CVD (hazard ratio=2.20, 95% confidence interval=1.32-3.68, Q1 versus Q4). Addition of LAFI, indexed maximum LA volume, or LA diameter to prediction models for AF or CVD did not significantly improve model discrimination for either outcome. CONCLUSIONS: In our prospective investigation of a moderate-sized community-based sample, LAFI, a composite measure of LA size and function, was associated with incident AF and CVD. Addition of LAFI to the risk prediction models for AF or CVD, however, did not significantly improve their performance.
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Beta-Blocker Use Is Associated With Impaired Left Atrial Function in HypertensionBACKGROUND: Impaired left atrial (LA) mechanical function is present in hypertension and likely contributes to various complications, including atrial arrhythmias, stroke, and heart failure. Various antihypertensive drug classes exert differential effects on central hemodynamics and left ventricular function. However, little is known about their effects on LA function. METHODS AND RESULTS: We studied 212 subjects with hypertension and without heart failure or atrial fibrillation. LA strain was measured from cine steady-state free-precession cardiac MRI images using feature-tracking algorithms. In multivariable models adjusted for age, sex, race, body mass index, blood pressure, diabetes mellitus, LA volume, left ventricular mass, and left ventricular ejection fraction, beta-blocker use was associated with a lower total longitudinal strain (standardized beta=-0.21; P=0.008), and lower LA expansion index (standardized beta=-0.30; P < 0.001), indicating impaired LA reservoir function. Beta-blocker use was also associated with a lower positive strain (standardized beta=-0.19; P=0.012) and early diastolic strain rate (standardized beta=0.15; P=0.039), indicating impaired LA conduit function. Finally, beta-blocker use was associated with a lower (less negative) late-diastolic strain (standardized beta=0.15; P=0.049), strain rate (standardized beta=0.18; P=0.019), and a lower active LA emptying fraction (standardized beta=-0.27; P< 0.001), indicating impaired booster pump function. Use of other antihypertensive agents was not associated with LA function. CONCLUSIONS: Beta-blocker use is significantly associated with impaired LA function in hypertension. This association could underlie the increased risk of atrial fibrillation and stroke seen with the use of beta-blockers (as opposed to other antihypertensive agents) demonstrated in recent trials.
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C'est LAVi: What Left Atrial Dilatation Tells Us About Diastolic Function in Aortic StenosisCalcific degenerative aortic valve stenosis (AS) is the most common acquired form of heart valve disease that afflicts the elderly population1 and usually comes to attention when an echocardiogram is ordered to evaluate a systolic murmur in an older subject. As is evident to anyone practicing cardiology these days, the advent of transcatheter aortic valve replacement has focused much attention on the evaluation and optimal treatment of patients with AS. AS often has a long latency period in which symptoms are absent, and, importantly, sudden unexpected cardiac death is rare.2,3 With symptom onset, survival is markedly reduced without intervention.4–6 For symptomatic patients with severe AS and normal flow-high gradient characteristics and normal left ventricular ejection fraction (LVEF) (stage D1), aortic valve replacement (AVR) is a class 1 indication. Similarly, for asymptomatic patients with severe AS and LVEF less than fifty percent not because of another cause (stage C2), AVR also is indicated.
