Influence of blood pressure on left atrial size. The Framingham Heart Study

Influence of regression of left ventricular hypertrophy on left atrial size and function in patients with moderate hypertension

OBJECTIVES

The aim of the study was to evaluate the effect of regression of left ventricular (LV) hypertrophy on left atrial (LA) size and function in patients treated with telmisartan, an angiotensin II receptor blocker.

METHODS

Patients population included 80 patients with mild-moderate LV hypertrophy treated with telmisartan. Patients were followed over a period of 12 months from the start of telmisartan treatment. LA size was measured during systole from the parasternal long-axis view from M-mode. Atrial function was assessed by Doppler-echocardiography and the following parameters were measured: transmitral peak A velocity, atrial filling fraction, atrial ejection force (AEF), peak E velocity, deceleration time and isovolumic relaxation time, LA maximal and minimal volume, and LV cardiac mass index (LVMI).

RESULTS

All patients had an increased LVMI and decrease during follow-up. LA dimensions were greater at baseline and reduced after 1 year of treatment. LA volume indexes maximal volume, minimal volume and P volume were reduced compared with baseline value (maximal volume from 35+/-5 to 32+/-5, p<0.05; minimal volumes from 14+/-2 to 10+/-4, p<0.05). AEF, a parameter of atrial systolic function, increased from 12+/-3 to 15+/-2.4 (p<0.01). The reduction of LA volumes correlate with reduction of LVMI (LA maximal volume and LVMI r = 0.45; p<0.01; LA minimal volume and LVMI r = 0.34; p<0.05). A positive correlation was also found between LV mass index and P volume (r = 0.41; p<0.01), LV mass index and LA active emptying volume (r = 0.39; p<0.01), and LV mass index and LA total emptying volume (r = 0.38; p<0.05).

CONCLUSIONS

The present study suggests that regression of LV hypertrophy due to telmisartan is associated with reduction of LA volumes that expresses variation of LV end-diastolic pressure. The reduction of LV end-diastolic pressure is associated with an increase in diastolic filling and with a significant reduction of active and passive emptying contribution of left atrium to LV stroke volume.

Left atrial volume and geometry in healthy aging: the Cardiovascular Health Study

BACKGROUND

The left atrium is a validated marker of clinical and subclinical cardiovascular disease. Left atrial enlargement is often seen among older individuals; however, there are few population-based data regarding normal left atrial size among older persons, especially from those who are healthy, and from women. Furthermore, because the left atrium is a 3D structure, the commonly used parasternal long-axis diastolic diameter often underdiagnoses left atrial enlargement.

METHODS AND RESULTS

We evaluated left atrial size in 230 healthy participants (mean age, 76+/-5 years) free of prevalent cardiac disease, rhythm abnormality, hypertension, and diabetes selected from the Cardiovascular Health Study, a prospective community-based study of risk factors for cardiovascular disease in 5888 elderly participants. In addition to the standard long-axis measurement, we obtained left atrial superoinferior and lateral diameters and used these dimensions to estimate left atrial volume. These measurements were used to generate reference ranges for determining left atrial enlargement in older men and women, based on the 95% percentiles of the left atrial dimensions in healthy participants, both unadjusted, and after adjustment for age, height, and weight. In healthy elderly subjects, indices of left atrial size do not correlate with age or height but with weight and other measures of body build.

CONCLUSIONS

These data provide normative reference values for left atrial size in healthy older women and men. The results should be useful for refining diagnostic criteria for left atrial dilation in the older population and may be relevant for cardiovascular risk stratification.

Diastolic dysfunction as a link between hypertension and heart failure

LVDD as an early measure of myocardial end-organ damage is commonly associated with hypertension and may well precede development of LVH in hypertension. About half of the patients presenting with heart failure have a normal ejection fraction, a clinical syndrome that is commonly referred to as HFPEF or diastolic heart failure and is commonly associated with impaired LV relaxation and increased diastolic stiffness. DD and HFPEF are commonly associated with advancing age and hypertension and increase in prevalence in association with these conditions, but there is a paucity of data on any specific therapeutic regimen. Hypertension control appears to be the most effective strategy in improving diastolic function and possibly for reducing the morbidity and mortality associated with HFPEF.

Postoperative atrial fibrillation

Atrial fibrillation is a common arrhythmia that occurs after cardiac surgery. It is associated with an increase in morbidity, length of hospital stay and mortality. Patients who are at higher risk of postoperative atrial fibrillation should receive prophylactic treatment. Atrial fibrillation usually resolves spontaneously after heart rate is controlled; however, if patients are highly symptomatic or hemodynamically unstable, sinus rhythm should be restored by electrical or pharmacologic cardioversion.

Left atrial size in 164 hypertensive patients: an echocardiographic and ambulatory blood pressure study

BACKGROUND

Left atrial enlargement (LAE) is associated with an increased risk of death and cardiovascular (CV) hospitalization. Whether or not LAE reflects early structural change from hypertension is unclear.

HYPOTHESIS

The aim of this study was to evaluate the relationship between LA size, 24-h blood pressure measurements, age, body mass index (BMI), and left ventricular mass index (LVMI) in hypertensive patients.

METHODS

We studied 164 outpatients (age range 30-76 years, 73 men and 91 women) with mild to moderate hypertension. Physical examination, electrocardiogram, noninvasive blood pressure monitoring (ABPM), Doppler echocardiogram were performed. Left ventricular mass index and LA dimensions were calculated. The sample was divided by age (< 60 and > or = 60 years).

RESULTS

Left ventricular hypertrophy (LVH) was present in 45% of patients aged < 60 years and in 70% of patients aged > or = 60 years (p = 0.002). Left atrial enlargement (> 4 cm) was present in 35% of elderly and in 24% of young patients (p = 0.31), and in 36% of patients with and 21% of patients without LVH (p = 0.0057). There was no significant difference in the younger patients with and without LVH. The incidence of obesity was low (31%) in the whole sample. The percentage of overweight in the elderly patients with LVH and higher LA size was equally low. Multivariate analysis showed age (p = 0.044) and LVMI (p = 0.002) as the only significant predictors of LA enlargement.

CONCLUSION

Since LAE is associated with a high risk of death and CV hospitalization, we emphasize the importance of development and use of drugs that inhibit LVH.

WITHDRAWN: Left atrial function and arterial hypertension

Left atrial enlargement is frequently observed in many cardiac diseases. One of the main determinants of left atrial size is ventricular diastolic function. It has recently been suggested that left atrial volume might be the morphophysiologic expression of long-term modifications induced by diastolic function. Furthermore, left ventricular remodelling, such as it happens in hypertensive patients, is another important determinant of atrial volume. All the volumetric modifications of the left atrium, during cardiac cycle, are involved in hypertensive damage. Therefore, left atrial function impairment represents the result of morphological and haemodynamic alterations observed in hypertension. Actually, many techniques, invasive and non-invasive, are available with the purpose to investigate the real atrial dimensions and provide a suitable assessment of atrial function. Recently, it has been demonstrated that the degree of left atrial enlargement is associated with adverse prognosis in different clinical setting. The predictive value of left atrial volume seems to be independent of left ventricular systolic and diastolic function, but the use of left atrial volume for risk stratification is yet an evolving science: more data are required with respect to the natural history of left atrial remodelling in disease, the degree of left atrial modifiability with therapy and whether regression of left atrial size translates into improved cardiovascular outcome.Journal of Human Hypertension advance online publication, 14 August 2008; doi:10.1038/jhh.2008.96.

Possible beneficial effect of olmesartan medoxomil on left atrial function in patients with hypertension : noninvasive assessment by acoustic quantification

BACKGROUND AND OBJECTIVE

Hypertension alters the diastolic properties of the left ventricle and results in deterioration in the structure and function of the left atrium. We aimed to evaluate whether olmesartan medoxomil has an effect on left atrial function in hypertensive patients.

METHODS

Fifty hypertensive patients and 20 controls were included in the study. Hypertensive patients were treated with olmesartan medoxomil for 8 weeks. Before and after treatment, study participants were examined by acoustic quantification and tissue Doppler imaging. Left atrial reservoir function was assessed by end-diastolic volume (EDV), end-systolic volume (ESV), reservoir volume (RV) and peak filling rate (PFR). Left atrial booster pump function was assessed by atrial emptying volume (AEV), atrial emptying fraction (AEF) and peak atrial emptying rate (PAER). Left atrial conduit function was assessed by rapid emptying volume (REV), rapid emptying fraction (REF), REV/AEV ratio, and the ratio of peak rapid emptying rate and PAER (PRER/PAER).

RESULTS

Atrial RV and PFR were significantly increased in hypertensive subjects (48.30 +/- 19.28 mL vs 34.35 +/- 14.26 mL, p < 0.001; 267.26 +/- 126.52 mL/s vs 206.81 +/- 107.17 mL/s, p < 0.05) compared with controls, while the REV/AEV ratio was decreased in hypertensive patients compared with controls (2.86 +/- 0.85 vs 3.69 +/- 2.13, p < 0.001). After therapy with olmesartan medoxomil, atrial RV (48.30 +/- 19.28 mL vs 40.50 +/- 17.59 mL) and PFR decreased (267.26 +/- 126.52 mL/s vs 220.40 +/- 108.56 mL/s, p < 0.05) and the REV/AEV ratio increased (2.86 +/- 0.85 vs 3.14 +/- 0.43, p < 0.05) in hypertensive patients.

CONCLUSION

Our novel findings indicate that left atrial function is impaired in hypertensive patients, and that olmesartan medoxomil can improve left atrial function in this context. Our study also showed that acoustic quantification is useful for non-invasive evaluation of the benefits of treatment on left atrial function.

Metabolic syndrome and risk of development of atrial fibrillation: the Niigata preventive medicine study

BACKGROUND

The metabolic syndrome consists of a cluster of atherosclerotic risk factors, many of which also have been implicated in the genesis of atrial fibrillation (AF). However, the precise role of the metabolic syndrome in the development of AF is unknown.

METHODS AND RESULTS

This prospective, community-based, observational cohort study was based on an annual health check-up program in Japan. We studied 28 449 participants without baseline AF. We used 2 different criteria for the metabolic syndrome--the guidelines of the National Cholesterol Education Program Third Adult Treatment Panel (NCEP-ATP III) and those of the American Heart Association/National Heart, Lung, and Blood Institute (AHA/NHLBI)--to study the risk of development of new-onset AF. The metabolic syndrome was present in 3716 subjects (13%) and 4544 subjects (16%) using the NCEP-ATP III and AHA/NHLBI definitions, respectively. During a mean follow-up of 4.5 years, AF developed in 265 subjects (105 women). Among the metabolic syndrome components, obesity (age- and sex-adjusted hazard ratio [HR], 1.64), elevated blood pressure (HR, 1.69), low high-density lipoprotein cholesterol (HR, 1.52), and impaired fasting glucose [corrected] (HR, 1.44 [NCEP-ATP III] and 1.35 [AHA/NHLBI]) showed an increased risk for AF. The association between the metabolic syndrome and AF remained significant in subjects without treated hypertension or diabetes by the NCEP-ATP III definition (HR, 1.78) but not by the AHA/NHLBI definition (HR, 1.28).

CONCLUSIONS

The metabolic syndrome was associated with increased risk of AF. The metabolic derangements of the syndrome may be important in the pathogenesis of AF.

Body Mass Index is an Independent Determinant of Left Atrial Size

BACKGROUND

Obesity is a risk factor for atrial fibrillation (AF) but the mechanisms underlying this association are unclear. We aimed to assess whether body mass index (BMI) is an independent determinant of left atrial size, in subjects in sinus rhythm.

METHODS

Subjects were consecutive ambulatory patients aged >/=18 years who underwent outpatient transthoracic echocardiography at a major metropolitan teaching hospital in Sydney, Australia. At the time of examination, age, sex, height and weight were measured. Left atrial (LA) area was measured on ultrasound by planimetry. Left ventricular (LV) function and LV posterior wall thickness were measured by M-mode.

RESULTS

Of 4859 consecutive subjects who underwent outpatient echocardiography at our institution over a three-year period, we analysed echocardiographic data from 2534 aged >/=18 years with confirmed sinus rhythm, normal LV contractility and no evidence of significant aortic or mitral valve disease. In these subjects (age 47+/-16.6 years, BMI 27.1+/-6.1, 53% male), BMI was a significant predictor of LA size (p<0.001), independent of the significant influences of LV end-diastolic volume and LV posterior wall thickness. Average LA size was 18.5+/-4.0 cm(2) in those with normal BMI, 20.7+/-4.5 cm(2) in the overweight and 22.3+/-4.1cm(2) in obese subjects (p for trend <0.001).

CONCLUSIONS

Obesity is associated with increased left atrial size in subjects undergoing clinically indicated echocardiography, independent of the effects of left ventricular size and posterior wall thickness. This may contribute, at least in part, to the rising incidence of atrial fibrillation in the community.

Postoperative atrial fibrillation

Atrial fibrillation is a common arrhythmia after cardiac surgery. It is associated with an increase in morbidity, length of hospital stay, and mortality. Patients who are at higher risk of postoperative atrial fibrillation should receive prophylactic treatment. Atrial fibrillation usually resolves spontaneously after heart rate is controlled; however, if patients are highly symptomatic or hemodynamically unstable, sinus rhythm should be restored by electrical or pharmacologic cardioversion. Patients with atrial fibrillation of more than 48 hours should receive antithrombotic therapy for thromboembolism prevention.

Effect of obesity on P-wave dispersion and QT dispersion in women

OBJECTIVE

The aim of this study was to investigate the effect of obesity on dispersion of P-wave duration and QTc interval in obese women.

METHODS

Forty-two obese women (Body mass index (BMI)=40+/-3 kg/m(2), mean age 45+/-9 years) and compared age-matched (BMI=22+/-1 kg/m(2), mean age 41+/-6 years) twenty-five non-obese women were included in our study. Maximum and minimum P-wave duration, P-wave dispersion (difference between the maximum and the minimum P-wave duration), maximum and minimum QTc interval, and QTc dispersion (the difference between the maximum and the minimum QTc interval) were measured from 12-lead ECG. ECG's were transferred to a personal computer via a scanner and then used for magnification of 400 times by Adobe Photoshop software.

RESULTS

There was significant difference in BMI (40+/-3 vs 22+/-1 kg/m(2), P<0.001, respectively) between obese and non-obese women. Obese women had higher Max. P-wave duration (116+/-11 vs 94+/-14 ms, P<0.001), P-wave dispersion (51+/-15 vs 26+/-11 ms, P<0.001), Max. QTc interval (449+/-38 vs 419+/-30 ms, P<0.001) and QTc dispersion (57+/-23 vs 38+/-15 ms, P<0.001) compared to non-obese women. A significant correlation was found between BMI and Max. P-wave duration (r=0.584, P<0.001), P-wave dispersion (r=0.621, P<0.001), Max. QTc interval (r=0.410, P<0.001), and QTc dispersion (r=0.429, P<0.001). In the linear regression analysis, compared to co-morbidity factors such as age, hypertension, diabetes mellitus and smoking, there was significant association between only BMI and electrocardiographic values (P-wave and QTc dispersion).

CONCLUSION

We concluded that obesity caused significant increase in P-wave and QTc dispersion. Therefore, obese women may not only be under the risk of ventricular arrhythmias, but also they may under the risk of atrial arrhythmias.

The interplay between haemodynamic load, brain natriuretic peptide and left atrial size in the early stages of essential hypertension

OBJECTIVE

Left atrial (LA) enlargement is an index of adverse cardiovascular events. We sought to investigate any possible correlation between haemodynamic load, neurohumoral factors and LA size in the early stages of essential hypertension.

METHODS

We studied 94 consecutive middle-aged subjects, with newly diagnosed stage I-II essential hypertension without left ventricular (LV) hypertrophy and 34 age and sex-matched normotensive individuals. Ambulatory blood pressure (BP) monitoring, plasma levels of brain natriuretic peptide (BNP), metabolic profile and left atrial volume index (LAVI), an echocardiographic measurement of LA volume indexed for the body surface area, constituted the work-up of all subjects.

RESULTS

Hypertensive compared with normotensive subjects had significantly increased office and ambulatory systolic and diastolic BP (P < 0.0001 for all cases) as well as body mass index and waist-to-hip ratio (P < 0.05 for both cases). BNP levels were greater in hypertensive compared with normotensive subjects but were not statistically significant (20.4 versus 17.1 pg/ml, P = NS). Hypertensive compared with normotensive subjects also had significantly increased LV mass index (105 versus 84 g/m, P < 0.0001), LA diameter (39 versus 36 mm, P < 0.0001), and LAVI (22 versus 19 ml/m, P < 0.05). In the hypertensive population, LAVI exhibited significant positive relationships with office systolic BP, ambulatory pulse pressure, LV mass index and BNP. In multiple linear regression analysis only LV mass index and BNP were significantly associated with LAVI (beta = 0.298, P = 0.030 and beta = 0.322, P = 0.009, respectively).

CONCLUSIONS

Increased LAVI, closely associated with LV mass index and BNP, was still found in the early stages of essential hypertension. However, the clinical significance of these findings remains to be elucidated in future studies.

Effect of weight loss on P wave dispersion in obese subjects

OBJECTIVE

The aim of this study was to investigate effect of loss weight on P wave dispersion in obese subjects.

RESEARCH METHODS AND PROCEDURES

After a 12-week weight loss program (diet and medical therapy), a total of 30 (24 women and six men) obese subjects who had lost at least 10% of their original weight were included in the present study. All subjects underwent a routine standard 12-lead surface electrocardiogram. Electrocardiograms were transferred to a personal computer by a scanner and then magnified 400 times by Adobe Photoshop software (Adobe Systems, Mountain View, CA). P wave dispersion, which is also defined as the difference between the maximum P wave duration and the minimum P wave duration, was also calculated.

RESULTS

After a 12-week weight loss program, BMI (p < 0.001), maximum P wave duration (p < 0.001), and P wave dispersion (p < 0.001) significantly decreased. The mean percentage of weight loss was 13% (10% to 20.3%). The decrease in the level of P wave dispersion (21 +/- 10 and 7 +/- 12 ms, p < 0.002) was more prominent in Group II (>or=12% loss of their original weight) than Group I (<12% loss of their original weight) after the weight loss program. A statistically significant correlation between decrease in the level of P wave dispersion and percentage of weight loss was found (r = 0.624, p < 0.001).

DISCUSSION

Substantial weight loss in obese subjects is associated with a decrease of P wave duration and dispersion. Therefore, these observations suggest that substantial weight loss is associated with improvement in atrial repolarization abnormalities in obese subjects.

Left atrial volume in end-stage renal disease: a prospective cohort study

BACKGROUND

End-stage renal disease (ESRD) is a high-risk condition and left ventricular hypertrophy (LVH) is the strongest risk factor in this population.

OBJECTIVE AND METHODS

Since the prognostic value of left atrial (LA) size in ESRD is still unknown, we performed a prospective cohort study aimed at testing the prognostic value of LA volume in a cohort of 249 ESRD patients.

RESULTS

Both un-indexed and indexed LA volume (LAV) was significantly higher in dialysis patients than in healthy subjects (P < 0.001). On multivariate analysis only left ventricular mass index (LVMI), LV ejection fraction (LVEF), ratio of early (E) to late atrial (A) mitral Doppler peak flow velocity (E/A ratio) and antihypertensive treatment maintained an independent association with LAV. During the follow-up 113 patients died. LAV added significant prognostic power to a multivariate Cox model of all-cause death and the model based on height provided the best data fit. Notably, this index maintained an independent predictive value for death (P = 0.03) also when LVMI and LVEF were jointly forced into the Cox's model. Neither crude nor body surface area (BSA)-adjusted LAV had an independent association with death when tested in the Cox model including LVMI and LVEF.

CONCLUSIONS

In patients with ESRD, LAV indexed for height displays prognostic value beyond and above that provided by LV mass and function.

Myocardial collagen turnover in normotensive obese patients: relation to insulin resistance

OBJECTIVES

The present study was undertaken to assess the differential impact of insulin resistance, leptin and body composition on myocardial mass and serum markers of cardiac fibrosis in obese subjects, within a small range of elevated BMI (30-40 kg/m(2)), without pulmonary disease, cardiovascular disease, hypertension, cardiac hypertrophy or other cardiovascular disease.

BACKGROUND

Obesity is an independent predictor of left ventricular mass (LVM) and is associated with disturbances in cardiac structure. The extent of the interstitial fibrosis in obese patients is not known, especially in the absence of cardiac hypertrophy.

METHODS AND RESULTS

We included 160 obese subjects. The LVM was obtained using the Devereux formula. Body composition was estimated from a total body scan. Insulin sensitivity was assessed by homeostasis model assessment (HOMA), and cardiac collagen turnover by measurement of procollagen type III aminopeptide (PIIINP). PIIINP was correlated to the E/A ratio (r=0.24; P=0.012), a marker of ventricular function. PIIINP was independently correlated with glucose concentration (r=0.27; P=0.004), indexes of insulin resistance (HOMA (r=0.27; P=0.003), insulin (r=0.24; P=0.008)), and parameters associated with the insulin-resistance syndrome (HDL-cholesterol r=-0.27; P=0.004) and fat trunk/fat leg ratio (r=0.24; P=0.053)). The variable most correlated with PIIINP was HDL-cholesterol, followed by HOMA (r (2)=0.13). When HOMA was substituted for blood glucose concentration and insulinemia (Model 2), HDL-cholesterol was strongly related to lower PIIINP levels, followed by higher glucose concentration (r (2)=0.21). Regression analyses showed that LVM had the strongest independent positive correlation with fat-free mass (FFM) (r=0.39; P=0.0002), followed by systolic blood pressure (r=0.19; P=0.034). Neither adipose mass nor height independently added information to multivariate models. The ratio leptin/fat mass was correlated with LVM (r=-0.27; P=0.004), but not independently of the FFM. Markers for fibrosis were not significantly correlated with LVM. As a result, FFM was the most predictive factor of LVM in obese subjects.

CONCLUSION

We found that serum levels of markers of cardiac collagen synthesis were significantly associated with insulin resistance in normotensive, nondiabetic obese subjects, and not related to the LVM. As a result, PIIINP could be a very early marker of ventricular dysfunction in these patients. Furthermore, we suggest that, for better detection of left ventricle hypertrophy in obese subjects, LVM should be indexed to FFM rather than to body surface area, or height.

Influence of obesity and insulin resistance on left atrial size in children

BACKGROUND

Left atrial (LA) enlargement has been linked to obesity and insulin resistance in adults.

OBJECTIVE

The purpose of this study was to determine the association in children between LA area and: (i) different components of the metabolic syndrome including obesity (OB), measures of body mass index (BMI) and waist circumference (WC), homeostasis model assessment-insulin resistance (HOMA-IR, proinsulin), and blood pressure (BP); and (ii) left ventricular mass (LVM) and diastolic function, measured using echo Doppler.

METHODS AND RESULTS

Eighty-four (44 females) subjects, [40 OB (BMI>95%), 28 overweight (BMI>85%)], 16 non-OB (BMI<85%)] aged 9+/-2.24 yrs were matched for sex and age. BMI, WC, BP, Tanner stage, and Mode M, 2-dimensional and Doppler transmitral echocardiography were assessed. A standard oral glucose tolerance test (OGTT) was done, measuring glucose, insulin, and proinsulin concentrations. Hypertension was only present in OB subjects (25%). Significant univariate association (p<0.001) was found between LA area and height (r=0.52), age (r=0.45), Tanner stage (r=0.45), BMI (r=0.66), WC (r=0.70), systolic BP (r=0.52), diastolic BP (r=0.53), proinsulin (r=0.36), and HOMA-IR (r=0.36). In the multivariate regression analysis, independent variables were entered in a stepwise fashion: initially, gender (p=0.006) and Tanner stage (p=0.011) were still significant independent correlates of LA area after adjusting for age, gender, and Tanner stage. Subsequently, incorporation of WC showed that WC (p=0.018) was a significant independent correlate of LA area. A larger model constructed to test the significance of adjustment factors, including WC, BP, LVM, and HOMA-IR showed that WC (p<0.001) was the only significant independent variable.

CONCLUSION

LA enlargement is present in childhood and is related to abdominal OB and insulin resistance, suggesting that children with central OB are at increased risk for cardiovascular disease.

Twenty four hour pulse pressure predicts long term recurrence in acute stroke patients

OBJECTIVES

The impact of different blood pressure (BP) components during the acute stage of stroke on the risk of recurrent stroke is controversial. The present study aimed to investigate by 24 hour BP monitoring a possible association between acute BP values and long term recurrence.

METHODS

A total of 339 consecutive patients with first ever acute stroke underwent 24 hour BP monitoring within 24 hours of ictus. Known stroke risk factors and clinical findings on admission were documented. Patients given antihypertensive medication during BP monitoring were excluded. The outcome of interest during the one year follow up was recurrent stroke. The Cox proportional hazard model was used to analyse association of casual and 24 hour BP recordings with one year recurrence after adjusting for stroke risk factors, baseline clinical characteristics, and secondary prevention therapies.

RESULTS

The cumulative one year recurrence rate was 9.2% (95% CI 5.9% to 12.3%). Multivariate Cox regression analyses revealed age, diabetes mellitus, and 24 hour pulse pressure (PP) as the only significant predictors for stroke recurrence. The relative risk for one year recurrence associated with every 10 mm Hg increase in 24 hour PP was 1.323 (95% CI 1.019 to 1.718, p = 0.036). Higher casual PP levels were significantly related to an increased risk of one year recurrence on univariate analysis, but not in the multivariate Cox regression model.

CONCLUSIONS

Elevated 24 hour PP levels in patients with acute stroke are independently associated with higher risk of long term recurrence. Further research is required to investigate whether the risk of recurrent stroke can be reduced to a greater extent by decreasing the pulsatile component of BP in patients with acute stroke.

Use of Real-time Three-dimensional Echocardiography to Measure Left Atrial Volume: Comparison with Other Echocardiographic Techniques

OBJECTIVES

Left atrial (LA) volume (LAV) is a prognostically important biomarker for diastolic dysfunction, but its reproducibility on repeated testing is not well defined. LA assessment with 3-dimensional (3D) echocardiography (3DE) has been validated against magnetic resonance imaging, and we sought to assess whether this was superior to existing measurements for sequential echocardiographic follow-up.

METHODS

Patients (n = 100; 81 men; age 56 +/- 14 years) presenting for LA evaluation were studied with M-mode (MM) echocardiography, 2-dimensional (2D) echocardiography, and 3DE. Test-retest variation was performed by a complete restudy by a separate sonographer within 1 hour without alteration of hemodynamics or therapy. In all, 20 patients were studied for interobserver and intraobserver variation. LAVs were calculated by using M-mode diameter and planimetered atrial area in the apical 4-chamber view to calculate an assumed sphere, as were prolate ellipsoid, Simpson's biplane, and biplane area-length methods. All were compared with 3DE.

RESULTS

The average LAV was 72 +/- 27 mL by 3DE. There was significant underestimation of LAV by M-mode (35 +/- 20 mL, r = 0.66, P < .01). The 3DE and various 2D echocardiographic techniques were well correlated: LA planimetry (85 +/- 38 mL, r = 0.77, P < .01), prolate ellipsoid (73 +/- 36 mL, r = 0.73, P = .04), area-length (64 +/- 30 mL, r = 0.74, P < .01), and Simpson's biplane (69 +/- 31 mL, r = 0.78, P = .06). Test-retest variation for 3DE was most favorable (r = 0.98, P < .01), with the prolate ellipsoid method showing most variation. Interobserver agreement between measurements was best for 3DE (r = 0.99, P < .01), with M-mode the worst (r = 0.89, P < .01). Intraobserver results were similar to interobserver, the best correlation for 3DE (r = 0.99, P < .01), with LA planimetry the worst (r = 0.91, P < .01).

CONCLUSIONS

The 2D measurements correlate closely with 3DE. Follow-up assessment in daily practice appears feasible and reliable with both 2D and 3D approaches.

Ambulatory blood pressure, target organ damage and left atrial size in never-treated essential hypertensive individuals

OBJECTIVE

To investigate the relationship between ambulatory blood pressure and different markers of target organ damage with left atrial size in never-treated essential hypertensive individuals.

METHODS

A total of 519 grade 1 and 2 hypertensive patients (mean age 46 +/- 12 years), referred for the first time to our outpatient clinic, underwent routine examinations: 24-h urine collection for microalbuminuria, ambulatory blood pressure monitoring over two 24-h periods in 4 weeks, echocardiography and carotid ultrasonography.

RESULTS

Left atrial diameter was increased in 17.3% of patients. No significant differences were found between subjects with and without increased left atrial size with regard to sex, duration of hypertension, clinic and mean 48-h ambulatory blood pressure, and daytime and night-time values. Compared with 429 patients with normal left atrial size, the 90 patients with enlarged left atria were older, had higher body mass index, were more frequently smokers, and included more individuals with the metabolic syndrome. The prevalence of left ventricular hypertrophy, of intima-media thickening, but not of microalbuminuria was significantly higher in subjects with increased left atrial size.

CONCLUSION

Left atrial enlargement is not an early echocardiographic finding in relatively young never-treated hypertensive individuals, as its prevalence is lower than that of well-validated markers of target organ damage, and it is unrelated to ambulatory blood pressure. Overweight, left ventricular hypertrophy, carotid intima-media thickening and metabolic syndrome are independent predictors of left atrial dimension, suggesting that changes in left atrial size represent an adaptive response when high blood pressure is associated with other cardiovascular or metabolic abnormalities.

Prevalence and correlates of left atrial enlargement in essential hypertension: role of ventricular geometry and the metabolic syndrome: the Evaluation of Target Organ Damage in Hypertension study

BACKGROUND

The cardiac effects of hypertension include a variety of structural changes such as increases in left ventricular mass (LVM) and left atrium (LA) size. Although data on hypertension-induced left ventricular changes are extensive, relatively little information is available on LA size from large-scale studies.

OBJECTIVE

We sought to assess the prevalence of LA enlargement in a large selected hypertensive population and to determine the relations of LA size to several biologic variables including left ventricular hypertrophy (LVH) and metabolic disturbances.

METHODS

A total of 2500 untreated and treated uncomplicated essential hypertensives consecutively attending, for the first time, our hospital out-patient hypertension clinic and included in the Evaluation of Target Organ Damage in Hypertension, an observational ongoing registry of hypertension-related target organ damage (TOD), were considered for this analysis. All patients underwent extensive clinical, laboratory and ultrasonographic investigations searching for cardiac (and extracardiac) TOD. The LA was considered enlarged when its anteroposterior diameter exceeded 3.7 cm in women and 4.1 cm in men. LVH was defined according to two different criteria: >/= 125 g/m in men and >/= 110 g/m in women; or >/= 51 g/m in men and >/=47 g/m in women.

RESULTS

Enlarged LA diameter was present in 24.5% of women and in 21.5% of men. Compared with 1925 patients with normal LA size, the 575 patients with enlarged LA were older, more frequently overweight, had higher systolic blood pressure and included a greater proportion of subjects under antihypertensive treatment, with diabetes and metabolic syndrome. Both LA size and prevalence of LA enlargement differed significantly in relation to left ventricular geometry and LVM, being greater in patients with concentric or eccentric LVH than in those with left ventricular concentric remodeling or normal geometry. The prevalence of LA enlargement was similar in patients with concentric and eccentric LVH. According to a logistic regression analysis, overweight, LVH, fasting blood glucose > 7.0 mmol/l and metabolic syndrome were the main independent predictors of LA enlargement in the overall population as well as in both untreated and treated hypertensive subgroups.

CONCLUSIONS

Our study suggests that: LA enlargement is a common echocardiographic finding in selected essential hypertensive patients with different left ventricular geometric patterns; LA size and LA enlargement is related to LVM rather than the type of LVH; and, in addition to LVH, overweight, high fasting glucose and metabolic syndrome are associated with LA dimensions.

Overweight and obesity as risk factors for atrial fibrillation or flutter: the Danish Diet, Cancer, and Health Study

PURPOSE

We examined the association between the body mass index analyzed as a continuous variable and by categorization according to World Health Organization criteria (normal weight, overweight and obesity) and the risk of a hospital (inpatient as well as outpatient) diagnosis of atrial fibrillation or flutter.

METHODS

Population-based prospective cohort study conducted from December 1993 to December 2001 among 47589 participants (22482 men and 25107 women) without preexisting cardiovascular or endocrine disease and with a mean age at baseline of 56 years (range 50-64 years) in the Danish Diet, Cancer, and Health Study. Subjects were followed up in the Danish National Registry of Patients and in the Danish Civil Registration System.

RESULTS

During follow-up (mean, 5.7 years) atrial fibrillation or flutter developed in 553 subjects (372 men and 181 women). The adjusted hazard ratio for atrial fibrillation or flutter per unit of increase in the body mass index was 1.08 (95% confidence interval [CI]: 1.05 to 1.11) in men and 1.06 (95% CI: 1.03 to 1.09) in women. When using normal weight as a reference, the adjusted hazard ratio for atrial fibrillation or flutter by overweight was 1.75 (95% CI: 1.35 to 2.27) in men and 1.39 (95% CI: 0.99 to 1.94) in women. The adjusted hazard ratio by obesity was 2.35 (95% CI: 1.70 to 3.25) in men and 1.99 (95% CI: 1.31 to 3.02) in women.

CONCLUSION

Overweight and obesity are associated with an increased risk of a diagnosis of atrial fibrillation or flutter.

Effect of rate and rhythm control on left ventricular function and cardiac dimensions in patients with persistent atrial fibrillation: Results from the RAte Control versus Electrical Cardioversion for Persistent Atrial Fibrillation (RACE) study

OBJECTIVES

The purpose of this study was to evaluate left ventricular function and atrial and ventricular diameters in patients with persistent atrial fibrillation (AF) treated with rate or rhythm control.

BACKGROUND

Restoration of sinus rhythm in patients with persistent AF may improve left ventricular function and reduce atrial dimensions. Adequate rate control in AF may preserve ventricular function.

METHODS

In 335 patients included in the RAte Control versus Electrical Cardioversion for Persistent Atrial Fibrillation (RACE) study, echocardiography was performed at baseline and 1- and 2-year follow-up. Echocardiography was compared between patients randomized to rate control (n = 160) and rhythm control (n = 175). In the rhythm control group, echocardiography was compared between patients with AF versus sinus rhythm at study end. Multivariate analysis was performed to determine parameters related to improvement of left ventricular function and increase of atrial diameters.

RESULTS

Fractional shortening improved significantly under rate and rhythm control (31 +/- 10% at baseline to 33 +/- 9% at 2 years, and from 30 +/- 10% to 34 +/- 9%; both P < .05, respectively). Under rate control, left and right atrial size increased significantly compared to baseline. Under rhythm control, only left atrial size increased. Multivariate analysis revealed that only sinus rhythm at study end was associated with an increase of fractional shortening. AF at study end, hypertension, and no use of angiotensin-converting enzyme inhibitors were independently associated with increase in atrial size.

CONCLUSIONS

Routine rate control prevents deterioration of left ventricular function. Maintenance of sinus rhythm is associated with improvement of left ventricular function and reduction of atrial sizes.

Diastolic dysfunction and left atrial volume

OBJECTIVES

We examined the association between diastolic function and left atrial volume indexed to body surface area (LAVi) in a population-based study.

BACKGROUND

Atrial enlargement has been suggested as a marker of the severity and duration of diastolic dysfunction (DD). However, the association between DD and atrial enlargement and their individual prognostic implications in the population is poorly defined.

METHODS

A cross-sectional sample of Olmsted County, Minnesota, residents > or =45 years of age (n=2,042) underwent comprehensive Doppler echocardiography and medical record review.

RESULTS

The LAVi increased with worsening DD: 23 +/- 6 ml/m2 (normal), 25 +/- 8 ml/m2 (grade I DD), 31 +/- 8 ml/m2 (grade II DD), 48 +/- 12 ml/m2 (grades III to IV DD). In bivariate analyses, age, left ventricular mass index, and DD grade were positively associated, whereas female gender and ejection fraction (EF) were inversely associated with LAVi (p <0.001 for all). When controlling for age, gender, cardiovascular (CV) disease, EF, and left ventricular mass, grade II DD was associated with a 24%, and grade III to IV DD was associated with a 62% larger LA volume (p <0.0001 for both). The area under the receiver-operator characteristic curve for LAVi to detect grade I, grade II, or grade III to IV DD was 0.57, 0.81, and 0.98, respectively. Both DD and LAVi were predictive of all-cause mortality, but when controlling for DD, LAVi was not an independent predictor of mortality.

CONCLUSIONS

These data suggest that DD contributes to LA remodeling. Indeed, DD is a stronger predictor of mortality; presumably it better reflects the impact of CV disease within the general population.

Effects of dipper and non-dipper status of essential hypertension on left atrial mechanical functions

AIM

This study was designed in order to investigate the effects of dipper and non-dipper status of hypertension on left atrial mechanical (reservoir, conduit and booster pump) functions with left atrial volume measurements by means of two-dimensional echocardiography in untreated systemic hypertensive patients.

METHOD

A total of 27 untreated dipper hypertensive patients, group I (15 female, 12 male, mean age 57+/-12 years); 23 untreated non-dipper hypertensive patients, group II (12 female, 11 male, mean age: 53+/-18 years); and 25 voluntary healthy individuals, group III (13 female, 12 male, mean age 53+/-10 years) were included into the study. Twenty-four hour blood pressure (BP) measurement was performed by the cuff-oscillometric method to evaluate the nocturnal decrease of BP. The patients whose night time mean blood pressure measurements were found 10% or more lower compared to mean day time measurements were classified as dipper hypertensive patients and the ones with a decrease of less than 10% were classified as non-dipper hypertensive patients. Left atrial (LA) volumes were measured echocardiographically according to biplane area-length method in apical four-chamber and two-chamber views. LA maximal volume (V(max)) was recorded at the onset of mitral opening, LA minimal volume (V(min)) was recorded at the onset of mitral closure and LA presystolic volume (V(p)) was recorded at the beginning of the atrial systole (p wave on ECG). All volume measurements were corrected to body surface area, and following LA emptying functions parameters were calculated: LA passive emptying volume (LAPEV)=V(max)-V(p), LA passive emptying fraction (LAPEF)=LAPEV/V(max), Conduit volume (CV)=left ventricular output volume-(V(max)-V(min)), LA active emptying volume (LAAEV)=V(p)-V(min), LA active emptying fraction (LAAEF)=LAAEV/V(p), LA total emptying volume (LATEV)=V(max)-V(min), LA total emptying fraction (LATEF)=LATEV/V(max).

RESULTS

LA volume indexes, V(max), V(min), and V(p), were significantly increased in the hypertensive subgroups (groups I and II) than in controls (p<0.001, p<0.001, p<0.001, respectively), but no significant difference was found in the V(p) values between group I and group II. V(max) and V(min) were larger in non-dipper hypertensive group than in dipper hypertensive group (p<0.05 and p<0.05, respectively). LAPEV and LAPEF were observed to be significantly reduced in both dipper and non-dipper hypertensives than in control (p<0.001 and p<0.05, respectively), and this difference was more obvious in non-dipper than dipper cases (p<0.001). Conduit volume was significantly lower in hypertensive groups than controls (p<0.05). LA active emptying volume (p<0.001) and LAA active emptying fraction (p<0.001) were significantly greater in hypertensive cases than in controls. Furthermore, LA active emptying volume in non-dipper hypertensive subjects was significantly greater than dipper hypertensive cases (p<0.05). Left atrial total emptying volume and left atrial total emptying fraction in both hypertensive groups were similar to control (p>0.05).

CONCLUSIONS

Atrial reservoir and booster pump functions increase in hypertensive patients, but this result is more prominent in non-dipper hypertensives than in dipper hypertensive patients.

Echocardiographic evidence of left atrial abnormality in young patients with lone paroxysmal atrial fibrillation

Usual assessment of left atrial size by 2-dimensional echocardiography in the anteroposterior dimension often underestimates the true atrial size. We compared 15 young patients (< or =50 years old) with lone paroxysmal atrial fibrillation to age-matched controls, and measured atrial size in the inferosuperior and mediolateral dimensions. These additional measurements and atrial volumes were significantly increased compared with control patients, revealing that patients with apparent "lone" paroxysmal atrial fibrillation may have subtle structural abnormalities of the left atrium.

Angiotensin-converting enzyme inhibition in hypertensive patients is associated with a reduction in the occurrence of atrial fibrillation

OBJECTIVE

The objective of this study was to determine the effects of angiotensin-converting enzyme inhibition (ACEI) versus long-acting calcium-channel blockade (CCB) on atrial fibrillation (AF) in patients with hypertension.

BACKGROUND

Atrial fibrillation is the most common significant cardiac arrhythmia, and angiotensin II has been implicated in its pathophysiology.

METHODS

This was a retrospective, longitudinal cohort study from a database of 8 million people in the U.S. Patients age > or =18 years with hypertension were eligible if they filled a prescription for either an ACEI or a CCB between January 1995 and June 1999. The use of all other antihypertensive medications was permitted. Patient chronic disease burden was assessed using a modified Charlson index. Patients were matched on a propensity score generated from a logistic regression model. A survival analysis approach was used to compare the incidence of AF between groups. The final cohorts were evaluated until June 2002, and the average follow-up was 4.5 years.

RESULTS

After cohort matching, 10,926 patients were included in the analysis and divided equally into the ACEI and CCB groups. Mean patient age was 65 years. The adjusted hazards ratio (95% confidence interval [CI]) in the ACEI versus CCB groups for the entire follow-up period was 0.85 (95% CI: 0.74 to 0.97) for new-onset AF, and the adjusted incidence ratio for AF-related hospitalizations was 0.74 (95% CI: 0.62 to 0.89).

CONCLUSIONS

Angiotensin-converting enzyme inhibition was associated with a reduced incidence of AF for patients with hypertension in a usual care setting. These results need to be confirmed in a large-scale randomized clinical trial.

Mitral annular calcification is a predictor for incident atrial fibrillation

BACKGROUND

Mitral annular calcification (MAC) has been associated with adverse cardiovascular disease outcomes and stroke in longitudinal and community-based cohorts. Prospective data are limited on its association with atrial fibrillation (AF).

METHODS

We examined the association between MAC and the long-term risk of AF over 16 years of follow-up in participants in the original cohort of the Framingham Heart Study who attended a routine examination between 1979 and 1981. MAC was assessed by M-mode echocardiography. cox proportional-hazards models were used to estimate hazard ratios (hr) for incident af.

RESULTS

Of 1126 subjects who had adequate echocardiographic assessment and were AF-free at baseline, 149 (13%) had MAC. There were 217 cases of incident AF (42 in subjects with MAC). The age- and sex-adjusted incidence rate was 362 per 10,000 person-years in subjects with MAC compared with 185 per 10,000 person-years in those without MAC. In multivariable-adjusted analyses, MAC was associated with an increased risk of AF (HR 1.6, 95% CI 1.1-2.2). This association was attenuated upon further adjustment for left atrial size (HR 1.4, 95% CI 0.9-2.0).

CONCLUSIONS

The association between MAC and incident AF may be mediated partially through left atrial enlargement. These data suggest the importance of better understanding the mechanisms involved in cardiac valvular calcification.

Cardiac remodeling in systemic hypertension

Experimental and clinical studies provide evidence that hypertension is causally related to adverse cardiac structural changes, such as LA enlargement, LV hypertrophy and myocardial fibrosis, and functional changes inclusive of LV systolic and diastolic dysfunction. These changes are induced by both hemodynamic and nonhemodynamic factors. There is accumulating evidence from several small and large clinical trials that various classes of antihypertensive therapy prevent and regress LVH and myocardial fibrosis. Prevention and reversal of LVH are associated with an improvement in cardiac function and with a decline in risk of adverse cardiovascular outcomes. Prevention of LVH should be a priority in subjects with hypertension. In patients with hypertensive heart disease, the components of therapy must comprise optimization of BP and regression of LVH. Future targets of therapy in hypertensive heart disease may include regression of myocardial fibrosis, normalization of LA size, and improvement in LV diastolic function.

Atrial fibrillation: hypertension as a causative agent, risk factor for complications, and potential therapeutic target

Atrial fibrillation and hypertension are 2 prevalent, and often coexistent, conditions in the North American population. Their incidence increases with advancing age, and they are responsible for considerable morbidity and mortality. Although the relation between the 2 conditions has long been known, the treatment of hypertension is not currently a focus in the clinical management of atrial fibrillation. Hypertension is associated with left ventricular hypertrophy, impaired ventricular filling, left atrial enlargement, and slowing of atrial conduction velocity. These changes in cardiac structure and physiology favor the development of atrial fibrillation, and they increase the risk of thromboembolic complications. Conventional therapy of atrial fibrillation has focused on interventions to control heart rate and rhythm and the prevention of stroke through the use of anticoagulant medications. In patients with atrial fibrillation, aggressive treatment of hypertension may reverse the structural changes in the heart, reduce thromboembolic complications, and retard or prevent the occurrence of atrial fibrillation. Specific pharmacotherapy could potentially play a major role in the primary and secondary prevention of atrial fibrillation and its complications.

Left atrial volume as an index of left atrial size: a population-based study

OBJECTIVES

We studied left atrial volume (LAV) as an index of atrial size.

BACKGROUND

Increased left atrial dimension (LAD) measured by M-mode echocardiography is a risk factor for atrial fibrillation, stroke, and death.

METHODS

A random sample of residents of Olmsted County, Minnesota, age > or =45 years (n = 2,042) underwent Doppler echocardiography with assessment of LAD and LAV. A subgroup of the population (n = 767) with no cardiovascular disease and normal systolic and diastolic function was used to develop reference ranges for LAD and LAV. In the total population, the prevalence of left atrial enlargement and the association between cardiovascular disease and left atrial size as determined by both indexes were assessed.

RESULTS

In the normal subgroup, both indexes were associated with gender and body size, thus models controlling for body size were used to determine gender-specific reference ranges for LAD and LAV. In the total population, left atrial enlargement was common, with a prevalence of 18% (men) and 12% (women) using LAD/body surface area (BSA) and of 16% (men and women) using LAV/BSA. The agreement between the indexes was only fair (kappa = 0.53). Adjusting for age and gender, LAV/BSA was more strongly associated with the presence of cardiovascular diseases than LAD/BSA.

CONCLUSIONS

We described a simple technique of measuring LAV, examined methods for indexing LAV, and described its normal range in a large, healthy reference cohort. Further, we find that in the community, left atrial enlargement is common and reflects the burden of cardiovascular disease.

Determinants of left atrial size in patients with newly diagnosed untreated hypertension

The present study determined the relationships between ambulatory blood pressure, left ventricular mass, body mass index, and other clinical and demographic variables to left atrial size in previously untreated hypertensive and normotensive subjects. Left atrial size was measured uni-dimensionally using M-mode echocardiography in 58 newly diagnosed never-treated hypertensive patients (office blood pressure 149/96 +/- 15/7 mmHg) and 28 normotensive control subjects (office blood pressure, 122/78 +/- 8/8 mmHg). Left ventricular mass, septal and posterior wall thickness were significantly increased in hypertensive compared to normotensive subjects (230 +/- 63 g versus 181 +/- 45 g, 1.1 +/- 0.2 cm versus 0.94 +/- 0.2 cm, and 1.04 +/- 0.2 cm versus 0.92 +/- 0.2 cm respectively; all p < 0.001). Left ventricular internal diameter (4.9 +/- 0.6 versus 4.8 +/- 0.4 cm, = 0.54) and left atrial size (3.74 +/- 0.48 versus 3.70 +/- 0.34 cm, p = 0.86) were not different between the two groups respectively. Body mass index, weight, left ventricular mass, wall thickness, and 24-h pulse pressure were significant correlates of left atrial size in the entire group and in the hypertensive subgroup. In the normotensive subgroup, body weight, body mass index, 24-h systolic and pulse pressure, and left ventricular mass were significant correlates. Multiple regression analyses in the entire group and the hypertensive subgroup alone showed that body mass index and left ventricular mass were the two best predictors of left atrial dimension. These data demonstrate that body mass index and left ventricular mass were the main correlates of left atrial size in patients with previously untreated stage I-II hypertension.

Left atrial dimensions determined by M-mode echocardiography in black and white older (> or =65 years) adults (The Cardiovascular Health Study)

Stroke and atrial fibrillation are common and serious illnesses in the elderly, the risks of which are substantially increased by left atrial (LA) enlargement. Despite growing recognition of the importance of LA enlargement, the distribution and correlates of LA dimension in the elderly have not been well defined. A total of 3,882 women and men aged >65 years were studied. Increased LA dimension was independently associated with increased weight, mitral annular calcium, regional wall motion abnormalities, mitral early peak inflow velocity, and left ventricular (LV) fractional shortening. Increased LA dimension was negatively associated with aortic leaflet thickening. The relation with LV fractional shortening was curvilinear with a nadir at 35% to 40%. LA dimension in black men was approximately 1.9 mm less than in white men in multivariate analyses. Adjustment for spirometric lung volumes and chest dimensions appeared to diminish the race-LA dimension relation. Thus, LA dimension is strongly associated with weight and with several echocardiographic valvular abnormalities; its relation with LV fractional shortening is U-shaped with a nadir at the borderline of LV functional impairment.

Left atrial size in children with hypertension: the influence of obesity, blood pressure, and left ventricular mass

OBJECTIVE

To evaluate the prevalence of left atrial enlargement and the correlates of left atrial size in children and adolescents with essential hypertension.

BACKGROUND

Left atrial enlargement has been associated with increased risk of cardiovascular disease, including stroke in adults. Risk factors for left atrial size in adults with hypertension include age, race, and obesity.

METHODS AND RESULTS

Patients (n =112; average age, 14.2 years) with essential hypertension were studied with echocardiography. The average left atrial dimension was 2.8 (+/- 0.5) cm; 51% patients had left atrial dimension >95% upper confidence limit. The patients with left atrial enlargement had greater body mass index (P <.05) than those without left atrial enlargement. In multiple regression analysis, height, body mass index, systolic blood pressure, and left ventricular geometry were significant independent correlates of left atrial size. Children with eccentric left ventricular hypertrophy were more likely to have a larger left atrial dimension.

CONCLUSIONS

Left atrial enlargement is prevalent in children and adolescents with essential hypertension. This may indicate an increased risk of cardiovascular disease morbidity and mortality. Control of obesity and blood pressure elevation offer two approaches for treatment that may prevent left atrial enlargement.

Heritability of left atrial size in the Tecumseh population

BACKGROUND

Little is known about the determinants of atrial size, and no study has analyzed whether genetic factors are involved in the pathogenesis of LA enlargement.

MATERIALS AND METHODS

We studied the heritability of echocardiographic left atrial size in 290 parents from the Tecumseh Blood Pressure Study and 251 children from the Tecumseh Offspring Study. All data from the parents and children were obtained at the same field office in Tecumseh, USA. Left atrial dimension was determined echocardiographically in accordance with American Society of Echocardiography guidelines with the use of leading-edge-to-leading-edge measurements of the maximal distance between the posterior aortic root wall and the posterior left atrial wall at end systole.

RESULTS

For correlation between the left atrial dimensions of the parents and their offspring, several models were generated to adjust the atrial dimensions in both groups for an increasing number of clinical variables. After removing the effect of age, gender, height, weight, skinfold thickness, and systolic blood pressure, parent-child correlation for left atrial size was 0.19 (P = 0.007). Further adjustment for left ventricular mass and for measuring left ventricular diastolic function increased the correlation to 0.25 (P = 0.001).

CONCLUSIONS

The present data indicate that heredity can explain a small but definite proportion of the variance in left atrial dimension.

Left ventricular mass and atrial volume determined by cine magnetic resonance imaging in essential hypertension

To evaluate the relationship between left atrial volume determined by cine magnetic resonance imaging and progression of left ventricular hypertrophy (LVH), left atrial volume and echocardiographic left ventricular mass (LVM) were measured in 30 hypertensive patients (15 without LVH and 15 with LVH) and 10 normotensive control subjects. We also evaluated the effects of antihypertensive therapy on the cardiac chamber volumes and LVM in hypertensive patients. The cardiac chamber volumes and LVM were indexed by body surface area. Although there were no significant differences in left ventricular chamber volumes among the three groups, both maximum and minimum left atrial volume indexes, and the LVM index were greater in hypertensive patients with LVH than in the other two groups. The LVM index was correlated with maximum left atrial volume index (r = 0.74, P < .0001), and minimum left atrial volume index (r = 0.76, P < .0001), respectively. Furthermore, in multivariate models, the LVM index was significantly correlated with maximum left atrial volume index. In hypertensive patients with LVH, both maximum and minimum left atrial volume indexes, and the LVM index significantly reduced after treatment. The percent of changes in maximum left atrial volume index after treatment was significantly correlated with the percent of changes in LVM index after treatment. In conclusion, our data indicate that LVH is an independent determinant of left atrial enlargement, and both LVH and left atrial enlargement may be reversed by some effective therapeutic interventions.

Left atrial diameter in nonvalvular atrial fibrillation: An echocardiographic study. Stroke Prevention in Atrial Fibrillation Investigators

BACKGROUND

The left atrium (LA) is usually enlarged in patients with nonvalvular atrial fibrillation (AF), but factors associated with LA diameter are incompletely defined.

METHODS AND RESULTS

This transthoracic echocardiographic cohort study includes 3465 participants with nonvalvular AF in 3 multicenter clinical trials. LA diameter determined by M-mode echocardiography was correlated with clinical and echocardiographic features by cross-sectional multivariate regression analyses. The mean LA diameter was 47 +/- 8 mm, on average 6 mm larger in those with AF at the time of echocardiography than in those with sinus rhythm (48 vs 42 mm, P <. 001). Patient age and body weight were independently predictive of LA diameter (P <.0001), but sex, body surface area, and body mass index were not. The estimated independent contribution of atrial rhythm to LA diameter was approximately 2.5 mm. Prolonged duration of AF, left ventricular dilatation and increased muscle mass, mitral regurgitation, annular calcification, and hypertension were additional independent predictors of LA diameter.

CONCLUSIONS

Multiple factors appear to contribute to LA enlargement in patients with nonvalvular AF, including the presence and persistence of the dysrhythmia.