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

The effect of urgent blood pressure reduction on left atrial strain in patients with hypertensive attack : Blood pressure lowering affects LA strain

BACKGROUND

Left atrial (LA) strain is a robust measure of LA function and is a useful parameter to assess left ventricular filling pressure. While initially considered as a "load-independent" parameter of LA function, later studies have found that acute changes in LA preload may affect LA reservoir and contractile strains. Acute alterations in blood pressure (BP) induces a change in left ventricular (LV) filling pressure without imposing a volume load, thus providing an opportunity to assess the effects of the change in LA afterload on LA mechanics. This study aims to understand the effect of acute BP changes on LA strain.

METHODS

A total of 40 patients admitted to the emergency department with hypertensive urgency were included. All patients underwent a comprehensive echocardiographic examination including measurement of LA reservoir, conduit and contractile strains. A repeat set of measurements were obtained after BP lowering.

RESULTS

Average drop in mean BP following intervention was 18.1 ± 5.4%. LV end-systolic and end-diastolic volumes, as well as maximum and minimum LA volumes were decreased significantly after BP reduction. The absolute increases in reservoir and contractile strains were 2.3 ± 4.7% (7.9% ± 13.8% relative to baseline) and 2.5 ± 3.3% (13.5 ± 19.0% relative to baseline), respectively, with both changes being statistically significant (p = 0.003 for reservoir and p < 0.001 for contractile strains). There were no significant changes in conduit strain after BP intervention (p = 0.79). The change in both LA reservoir and contractile strains were more evident in those with a previous diagnosis of hypertension and those with a smaller degree of change in mean BP after intervention.

CONCLUSION

In patients with an acute hypertension, lowering BP leads to an acute improvement in LA reservoir and contractile strains. Thus, acute changes in systemic BP should be considered when LA mechanics are evaluated.

Blood Pressure Trajectories for 16 Years and the Development of Left Ventricular Hypertrophy and Increased Left Atrial Size: The Korean Genome and Epidemiology Study

Background

Elevated single blood pressure (BP) measurement can be associated with the development of hypertension-mediated target organ damage including left ventricular hypertrophy (LVH) and left atrial (LA) enlargement (LAE). However, long-term patterns of BP and their effects on LVH and LAE are poorly understood. We evaluated the association between the BP trajectories and the presence of LVH and LAE.

Methods

We analyzed a total of 2,565 participants (1,267 males, 47.8 ± 6.7 years old) from the first biennial examination (2001-2002) of the Korean Genome and Epidemiology Study. The presence of LVH and LAE was identified by echocardiography performed at the 8^th biennial examination (2015-2016). Latent mixture modeling was used to identify trajectories in mid-BP ((systolic BP + diastolic BP)/2) over time. Linear logistic regression was used for assessing BP trajectories with the outcomes.

Results

We identified 4 distinct mid-BP trajectories: group 1 (lowest, 20.9%, n = 536), group 2 (36.2%, n = 928), group 3 (32.3%, n = 828), and group 4 (highest, 10.6%, n = 273). Compared with the lowest group, trajectories with elevated mid-BP had greater odds ratios having LVH and LAE by multivariable-adjusted regression models. Adjusted odd ratios for LVH were 2.033 (95% CI = 1.462–2.827, P < 0.001) for group 2, 3.446 (95% CI = 2.475–4.797, P < 0.001) for group 3, and 4.940 (95% CI = 3.318–7.356, P < 0.001) for group 4. Adjusted odd ratios for LAE were 1.200 (95% CI = 0.814–1.769, P = 0.358) for group 2, 1.599 (95% CI = 1.084–2.360, P = 0.018) for group 3, and 1.944 (95% CI = 1.212–3.118, P = 0.006) for group 4.

Conclusions

Higher long-term mid-BP was an independent risk factor of cardiac structural changes such as LVH and LAE among middle-aged population.

Imaging of the left atrium: pathophysiology insights and clinical utility

Left atrial imaging and detailed knowledge of its pathophysiology, especially in the context of heart failure, have become an increasingly important clinical and research focus. This development has been accelerated by the growth of non-invasive imaging modalities, advanced image processing techniques, such as strain imaging, and the parallel emergence of catheter-based left atrial interventions like pulmonary vein ablation, left atrial appendage occlusion, and others. In this review, we focus on novel imaging methods for the left atrium, their pathophysiological background, and their clinical relevance for various cardiac conditions and diseases.

Atrial fibrillation and cardiac fibrosis

The understanding of atrial fibrillation (AF) evolved from a sole rhythm disturbance towards the complex concept of a cardiomyopathy based on arrhythmia substrates. There is evidence that atrial fibrosis can be visualized using late gadolinium enhancement cardiac magnetic resonance imaging and that it is a powerful predictor for the outcome of AF interventions. However, a strategy of an individual and fibrosis guided management of AF looks promising but results from prospective multicentre trials are pending. This review gives an overview about the relationship between cardiac fibrosis and AF focusing on translational aspects, clinical observations, and fibrosis imaging to emphasize the concept of personalized paths in AF management taking into account the individual amount and distribution of fibrosis.

Integrated Care in Atrial Fibrillation: A Road Map to the Future

Atrial fibrillation (AF) is the most commonly encountered arrhythmia in clinical practice with an epidemiological coupling appreciated with advancing age, cardiometabolic risk factors, and structural heart disease. This has resulted in a significant public health burden over the years, evident through increasing rates of hospitalization and AF-related clinical encounters. The resultant gap in health care outcomes is largely twinned with suboptimal rates of anticoagulation prescription and adherence, deficits in symptom identification and management, and insufficient comorbid cardiovascular risk factor investigation and modification. In view of these shortfalls in care, the establishment of integrated chronic care models serves as a road map to best clinical practice. The expansion of integrated chronic care programs, which include multidisciplinary team care, nurse-led AF clinics, and use of telemedicine, are expected to improve AF-related outcomes in the coming years. This review will delve into current gaps in AF care and the role of integrated chronic care models in bridging fragmentations in its management.

Left Atrial Remodeling Assessed by Cardiac MRI after Conversion from Conventional Hemodialysis to In-Centre Nocturnal Hemodialysis

BACKGROUND

Left atrial (LA) volume is a well-established cardiovascular prognosticator in patients with end-stage renal disease. Although dialysis intensification is associated with left ventricular mass regression, there are limited data regarding LA remodeling. Using cardiac magnetic resonance imaging (CMR), we examined changes in LA size and function relative to ventricular remodeling and cardiac biomarkers after dialysis intensification.

METHODS

In this prospective 2-centre cohort study, 37 patients receiving conventional hemodialysis (CHD, 4 h/session, 3×/week) were converted to in-centre nocturnal hemodialysis (INHD 7-8 h/session, 3×/week); 30 patients remained on CHD. CMR and biomarkers were performed at baseline and repeated at 52 weeks.

RESULTS

After 52 weeks, there were no significant changes in the LA volumes or LA ejection fraction (EF) within either the CHD or INHD group, and no significant differences between the two groups. Correlations existed between changes in LA and LV end-diastolic volume index (EDVi, Spearman's r = 0.69, p < 0.001), LA and LV end-systolic volume index (ESVi, r = 0.44, p = 0.001), LAEF and LVEF (r = 0.28, p = 0.04), LA and RV EDVi (r = 0.51, p < 0.001), LA and RV ESVi (r = 0.29, p = 0.039), and LA ESVi and LV mass index (r = 0.31, p = 0.02). At baseline, indexed LA volumes positively correlated with NT-proBNP, whereas LAEF negatively correlated with NT-proBNP and Troponin I. After 52 weeks, changes in biomarker levels did not correlate with changes in LA volume or EF.

CONCLUSION

There was no significant change in LA size or systolic function after conversion to INHD. The significant correlations between LA and ventricular remodeling and cardiac biomarkers suggest common underlying pathophysiologic mechanisms.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT00718848.

Echocardiographic Left Ventricular Reverse Remodeling After 18 Months of Antihypertensive Treatment in Stage I Hypertension. Results From the Prever-Treatment Study

BACKGROUND

Antihypertensive treatment improves echocardiographic parameters of hypertensive target organ damage in stage II hypertension, but less is known about the effects in stage I hypertension.

METHODS

In a cohort study nested in the randomized double-blind trial PREVER-treatment, 2-dimensional echocardiograms were performed in 110 individuals, aged 54.8 ± 7.9 years-old, with stage I hypertension at baseline and after 18 months of treatment with chlorthalidone/amiloride or losartan.

RESULTS

At baseline, 66 (60%) participants had concentric remodeling. After antihypertensive treatment, systolic (SBP) and diastolic blood pressure (BP) were reduced from 141/90 to 130/83 mm Hg (P = 0.009). There was a significant reduction in left ventricular (LV) mass (LVM) index (82.7 ± 17.1 to 79.2 ± 17.5 g/m2; P = 0.005) and relative wall thickness (0.45 ± 0.06 to 0.42 ± 0.05; P < 0.001), increasing the proportion of participants with normal LV geometry (31% to 49%, P = 0.006). Left atrial (LA) volume index reduced (26.8 ± 7.3 to 24.9 ± 6.5 ml/m2; P = 0.001), and mitral E-wave deceleration time increased (230 ± 46 to 247 ± 67 ms; P = 0.005), but there was no change in other parameters of diastolic function. LVM reduction was significantly higher in the 2 higher tertiles of SBP reduction compared to the lower tertile.

CONCLUSIONS

Treatment of patients with stage I hypertension for 18 months promotes favorable effects in the LA and LV remodeling. This improvement in cardiac end-organ damage might be associated with reduction of long term clinical consequences of hypertensive cardiomyopathy, particularly heart failure with preserved ejection fraction.

Association of left atrial enlargement with ventricular remodeling in hypertensive Chinese elderly

BACKGROUND

It is not well known whether left atrial (LA) enlargement is associated with left ventricular (LV) remodeling in Asian subjects with preserved LV ejection fraction (LVEF ≥50%). Therefore, we studied whether LA enlargement is related to ventricular remodeling in hypertensive Chinese elderly with preserved LVEF.

METHODS

Data of 480 hypertensive Chinese elderly (age from 65 to 94 years) with LVEF ≥50% were consecutively included in the study.

RESULTS

We observed a total of 248 patients (51.7%) with increased LA size. Univariate analysis showed that LA size was positively related to duration of hypertension, prevalence of coronary heart disease and atrial fibrillation, interventricular septal thickness, LV posterior wall thickness, LV end-diastolic and end-systolic diameter, LV mass index, right ventricular (RV) diameter and aortic diameter; meanwhile, LA size was inversely related to LVEF and relative wall thickness of LV. Multivariate regression analysis showed that LA enlargement was positively related to duration of hypertension (P=.012) and RV diameter (P<.001).

CONCLUSIONS

Left atrial enlargement is independently associated with a longer duration of hypertension and RV dilative remodeling in hypertensive elderly with preserved LVEF. LA enlargement is an early sign of RV eccentric remodeling in hypertensive elderly.

Speckle tracking analysis: a new tool for left atrial function analysis in systemic hypertension: an overview

Speckle tracking echocardiography (STE) is an imaging technique applied to the analysis of left atrial function. STE provides a non-Doppler, angle-independent and objective quantification of left atrial myocardial deformation. Data regarding feasibility, accuracy and clinical applications of left atrial strain are rapidly gathering. This review describes the fundamental concepts of left atrial STE, illustrates its pathophysiological background and discusses its emerging role in systemic arterial hypertension.

Excessive interatrial adiposity is associated with left atrial remodeling, augmented contractile performance in asymptomatic population

PURPOSE

Pericardial adipose tissue had been shown to exert local effects on adjacent cardiac structures. Data regarding the mechanistic link between such measures and left atrial (LA) structural/functional remodeling, a clinical hallmark of early stage heart failure (HF) and atrial fibrillation (AF) incidence, in asymptomatic population remain largely unexplored.

METHODS

This retrospective analysis includes 356 subjects free from significant valvular disorders, atrial fibrillation, or clinical HF. Regional adipose tissue including pericardial and periaortic fat volumes, interatrial septal (IAS), and left atrioventricular groove (AVG) fat thickness were all measured by multidetector computed tomography (MDCT) (Aquarius 3D Workstation, TeraRecon, San Mateo, CA, USA). We measured LA volumes, booster performance, reservoir capacity as well as conduit function, and analyzed their association with adiposity measures.

RESULTS

All four adiposity measures were positively associated with greater LA volumes (all P < 0.05), while IAS and AVG fat were also related to larger LA kinetic energy and worse reservoir capacity (both P < 0.01). In multivariate models, IAS fat thickness remained independently associated with larger LA volumes, increased LA kinetic energy and ejection force (β-coef: 0.17 & 0.15, both P < 0.05), and impaired LA reservoir and conduit function (β-coef: -0.20 & -0.12, both P < 0.05) after adjusting for clinical variables.

CONCLUSION

Accumulated visceral adiposity, especially interatrial fat depots, was associated with certain LA structural/functional remodeling characterized by impaired LA reservoir and conduit function though augmented kinetic energy and ejection performance. Our data suggested that interatrial fat burden may be associated with certain detrimental LA functions with compensatory LA adaptation in an asymptomatic population.

The role of imaging in hypertensive heart disease

Hypertensive heart disease (HHD) describes a spectrum of target organ response that includes left ventricular hypertrophy, systolic, and diastolic dysfunction. A variety of imaging techniques can be used to assess the various aspects of HHD. Echocardiography has for many years been the main imaging technique in the evaluation of HHD, but there is an increasing role for cardiovascular magnetic resonance (CMR) imaging due to its ability to provide an unrestricted field of view and noninvasive tissue characterization. This article reviews the current role of imaging for HHD with particular focus on echocardiography and CMR applications.

Caffeine in tea Camellia sinensis--content, absorption, benefits and risks of consumption

Therapeutic properties of tea Camellia sinensis are of particular interest since it has been consumed for ages and was always regarded as safe beverage. Tea is most popular beverage in the world because of its attractive aroma, exceptional taste, health promoting and pharmaceutical potential. Current results showed that antioxidative, antibacterial and other health effects are attributed to its caffeine content and caffeine - polyphenols interactions. An overview is given on caffeine content in different tea leaves beverage. Special attention is drawn to caffeine physiological effect on human organism. Controversies concerning the possible caffeine influence on human physical and psychological health are briefly summarized and presented.

Relationship of left atrial enlargement to persistence or development of ECG left ventricular hypertrophy in hypertensive patients: implications for the development of new atrial fibrillation

BACKGROUND

Persistence and development of ECG left ventricular hypertrophy (LVH) by Cornell product criteria are associated with an increased risk of atrial fibrillation compared with regression or continued absence of LVH. We postulated that this association might be in part mediated via greater left atrial enlargement (LAE) in patients with new and persistent ECG LVH.

METHODS AND RESULTS

Baseline and third year ECG LVH and left atrial systolic diameter were examined in 663 patients in the Losartan Intervention For Endpoint reduction in hypertension echocardiographic substudy who were in sinus rhythm at baseline and had no history of atrial fibrillation. Left atrial systolic diameter was measured and considered enlarged if more than 3.8 cm in women or more than 4.2 cm in men. Cornell product LVH above 2440 mm-ms was considered consistent with LVH. After 3 years follow-up, 238 patients (35.9%) had continued absence of Cornell product LVH, 156 (23.5%) had regression of LVH, 236 (35.6%) had persistent LVH and 33 patients (5.0%) developed new ECG LVH. Compared with third year mean left atrial systolic dimension and prevalence of LAE in patients with continued absence of LVH (3.62+/-0.52 cm, 12.6%), there were step-wise increases in patients with regression of LVH (3.71+/-0.49 cm, 20.5%), persistence of LVH (3.82+/-0.57 cm, 32.2%) and development of new ECG LVH (3.91+/-0.42 cm, 36.4%, both P<0.001). After controlling for differences in age, sex, baseline SBP, BMI and Sokolow-Lyon voltage, randomized treatment allocation, change in DBP and SBP between baseline and third year and for isovolumic relaxation time and presence of an abnormal mitral E/A ratio at baseline and third year, the odds of having LAE were significantly increased in patients with persistent LVH (odds ratio 1.8, 95% confidence interval 1.1-3.2, P=0.043) or new LVH (odds ratio 3.1, 95% confidence interval 1.3-7.7, P=0.016), but not in patients with regression of Cornell product LVH (odds ratio 1.1, 95% confidence interval 0.6-2.0, P=0.860).

CONCLUSION

Persistence or development of new ECG LVH during antihypertensive therapy are associated with an increased risk of LAE after 3-year follow-up, whereas regression of ECG LVH is not associated with an increased risk of LAE. These findings provide insight into a possible mechanism by which changes in ECG LVH are associated with changing risk of developing atrial fibrillation.

Predictive factors associated with left ventricular hypertrophy at baseline and in the follow-up period in non-diabetic hemodialysis patients

Hemodialysis (HD) patients frequently have an elevated left ventricular mass index (LVMI). Currently, left ventricular (LV) hypertrophy and dysfunction are considered to be the strongest predictors of cardiovascular mortality in dialysis patients. The objectives of the present study are to investigate the factors associated with elevated LVMI and to discuss therapeutic implications for the treatment strategy for pre-dialysis and HD patients. The correlation among biochemical values, physical specimens, and LVMI using echocardiography was prospectively analyzed in 30 non-diabetic HD patients in the Juntendo University Hospital. Measurement of these parameters was performed at 0, 12, and 24 months after initiation of HD. Systolic blood pressure (SP), human atrial natriuretic peptide (hANP), and hemoglobin (Hb) levels were significantly correlated with LVMI. SBP, residual glomerular filtration rate (rGFR), and serum albumin levels were identified as independent risk factors for LVMI in multivariate regression analysis at initiation of HD. SBP, hANP, and Hb levels were identified as independent risk factors for LVMI in multivariate regression analysis after 24 months. SBP, rGFR, and serum albumin levels were predictive factors for LVMI at initiation of HD. SBP, hANP, and Hb levels were also predictive factors for LVMI after initiation of HD.

Cardiac Function and Structure in Longitudinal Analysis of Echocardiography in Peritoneal Dialysis Patients

♦ Background

Echocardiography is widely used for the evaluation of cardiac structures and function. The prognostic value of assessment of left cardiac atrium (LA) size in peritoneal dialysis (PD) patients is still unclear. The objective of the present study is to investigate prospectively a longitudinal monitoring of echocardiography parameters after start of PD. We also investigated a correlation study among plasma atrial natriuretic peptide (ANP) level, LA size, and cardiac function undergoing aggressive treatment.

♦ Methods

Correlation among plasma ANP, LA size, and cardiac function was prospectively analyzed by Doppler echocardiography in 32 PD patients in Juntendo University Hospital, Tokyo. Measurement of these parameters was performed at 0, 6, 12, 18, and 24 months after start of PD. All patients were treated with an angiotensin type 1 receptor blocker to control blood pressure to less than 140/90 mmHg. Other antihypertensive drugs such as diuretics and/or calcium channel blockers were added if blood pressure rose to over 140/90 mmHg. Hemoglobin and hematocrit levels were targeted at 10.0 g/dL and 30.0% respectively with recombinant human erythropoietin treatment. A diuretic was added or patients decreased their water intake if ANP was more than 43.0 pg/mL or LA diameter (LAD) more than 39 mm, and for other basic markers of volume status. Cardiac function was measured before and after drainage of PD fluid to evaluate the influence of cardiac function.

♦ Results

LAD at start of dialysis (36 ± 4.6 mm) decreased significantly to 33 ± 3.3 mm ( p < 0.05), 33 ± 3.2 mm ( p < 0.05), and 33 ± 3.6 mm ( p < 0.05) after 6, 12, and 24 months, respectively. Ejection fraction after 6 months was significantly increased compared with that at start of dialysis ( p < 0.05). Left ventricular mass index (LVMI) after 6, 12, and 24 months was significantly decreased compared with that at start of dialysis ( p < 0.05). ANP was 56 ± 39 pg/mL at start of dialysis and decreased significantly to 33 ± 19 pg/mL after 24 months ( p < 0.05). ANP was significantly correlated with LAD ( r = 0.412, p < 0.01), transmitral A wave flow velocity ( r = 0.429, p < 0.01), and LVMI ( r = 0.426, p < 0.01). Instillation of the dialysis fluid did not affect any parameters except inferior vena cava dimension.

♦ Conclusions

This study demonstrates a reduction in LA size and LVMI in PD patients followed over 24 months. Left ventricular structure, contraction, and compliance were well preserved in PD patients undergoing aggressive treatment based on measurements of plasma ANP and LAD.

Telmisartan: a different angiotensin II receptor blocker protecting a different population?

The ONgoing Telmisartan Alone and in combination with Ramipril Global Endpoint Trial (ONTARGET()) showed that the angiotensin II receptor blocker (ARB) telmisartan was as protective as the reference-standard ramipril in a broad cross-section of patients at increased cardiovascular risk, but was better tolerated. Telmisartan has a unique profile among ARBs, with a high affinity for the angiotensin II type 1 receptor, a long duration of receptor binding, a high lipophilicity and a long plasma half life. This leads to sustained and powerful blood pressure lowering when compared with the first marketed ARBs, such as losartan and valsartan. Some pharmacological properties of telmisartan clearly distinguish it from other members of the ARB class and may contribute to the clinical effects seen with telmisartan. A class effect for ARBs cannot be assumed. To date, telmisartan is the only ARB that has been shown to reduce cardiovascular risk in at-risk cardiovascular patients.

Atrial Remodeling And Atrial Fibrillation: Mechanistic Interactions And Clinical Implications

Atrial fibrillation (AF) is the most common arrhythmia in clinical practice. The prevalence of AF increases dramatically with age and is seen in as high as 9% of individuals by the age of 80 years. In high-risk patients, the thromboembolic stroke risk can be as high as 9% per year and is associated with a 2-fold increase in mortality. Although the pathophysiological mechanism underlying the genesis of AF has been the focus of many studies, it remains only partially understood. Conventional theories focused on the presence of multiple re-entrant circuits originating in the atria that are asynchronous and conducted at various velocities through tissues with various refractory periods. Recently, rapidly firing atrial activity in the muscular sleeves at the pulmonary veins ostia or inside the pulmonary veins have been described as potential mechanism,. AF results from a complex interaction between various initiating triggers and development of abnormal atrial tissue substrate. The development of AF leads to structural and electrical changes in the atria, a process known as remodeling. To have effective surgical or catheter ablation of AF good understanding of the possible mechanism(s) is crucial.Once initiated, AF alters atrial electrical and structural properties that promote its maintenance and recurrence. The role of atrial remodeling (AR) in the development and maintenance of AF has been the subject of many animal and human studies over the past 10-15 years. This review will discuss the mechanisms of AR, the structural, electrophysiologic, and neurohormonal changes associated with AR and it is role in initiating and maintaining AF. We will also discuss briefly the role of inflammation in AR and AF initiation and maintenance, as well as, the possible therapeutic interventions to prevent AR, and hence AF, based on the current understanding of the interaction between AF and AR.

Impact of Mild Hypertension on Left Atrial Size and Function

Background— Left atrial (LA) enlargement has been documented to occur in moderate and severe hypertension.

Methods and Results— One hundred twelve mild hypertension patients were prospectively recruited and compared with 198 healthy volunteers. All recruits had a transthoracic echocardiogram. Maximum LA biplane volume, minimum LA biplane volume, and pre ‘p’-LA biplane volume were measured, and left atrial passive, active emptying, and conduit volumes were calculated at baseline and in a subgroup of patients after 12 months. After adjusting for age, gender, and body mass index, maximum LA biplane volume, pre ‘p’-LA biplane volume, and their indexed volumes were increased in the hypertension group. Active emptying volume and fraction were significantly increased in the hypertension group, with no change in conduit and passive volumes. Subgroup analysis comparing hypertensives with normal/mildly increased left ventricular mass (group 1) with those with moderate/severely increased left ventricular mass (group 2) at baseline demonstrated that maximum LA biplane volume (62.8�17.9 mL versus 45.4�13.7 mL; P <0.001) was significantly increased in group 2. Active emptying volume was also increased.

Conclusion— Even mild hypertension seems to be associated with a reduction in early diastolic filling. This results in augmented late left ventricular diastolic filling due to active atrial contraction and may be the mechanism for the increase in left atrial size.

Echocardiographic evaluation of left atrial size and function: current understanding, pathophysiologic correlates, and prognostic implications

Left atrial (LA) volume has recently been identified as a potential biomarker for cardiac and cerebrovascular disease. However, evidence regarding the prognostic implications of LA volume still remains unclear. Evaluation of LA size and function using traditional and more recent echocardiographic parameters is potentially feasible in the routine clinical setting. This review article discusses the conventional and newer echocardiographic parameters used to evaluate LA size and function. Conventional parameters include the assessment of phasic atrial activity using atrial volume measurements, transmitral Doppler peak A velocity, atrial fraction, and the atrial ejection force. Newer parameters include Doppler tissue imaging (DTI) including segmental atrial function assessment using color DTI, strain, and strain rate. In addition, an overview of the implications and clinical relevance of the findings of an enlarged left atrium, from currently available literature, is presented.

How many patients would be misclassified using M-mode and two-dimensional estimates of left atrial size instead of left atrial volume? A three-dimensional echocardiographic study

OBJECTIVES

Left atrial size has shown prognostic importance in a variety of cardiac conditions. Diameters, area, and volume derived from M-mode and two-dimensional (2D) echocardiography are commonly used to estimate left atrial size. However, M-mode and 2D measures of left atrial size rely on various geometrical assumptions and their accuracy remains to be determined. To address this issue, we compared M-mode and 2D parameters routinely used to estimate left atrial size with three-dimensional (3D) echo measured left atrial volume (LAV) as a reference standard.

METHODS

We studied 104 patients (55% males, 62 +/- 15 years, range 10-87 years), presenting for a routine echocardiographic evaluation.

RESULTS

The mean 3D LAV for the study population was 90 +/- 68 ml (range 24-458 ml). We found highly significant (P < 0.0001) correlations between 3D LAV and left atrial anterior-posterior (r = 0.78, 95% CI = 0.69-0.85), superior-inferior (r = 0.74, 95% CI = 0.63-0.81) and medial-lateral (r = 0.91, 95% CI = 0.86-0.93) diameters. A highly significant correlation was also found between 3D LAV and left atrial area (r = 0.94, 95% CI = 0.91-0.96). However, using M-mode anterior-posterior diameter or left atrial area would have misclassified 57% and 70% of our study patients, respectively, regarding the degree of left atrial dilatation. Closer correlations and narrower confidence intervals were found between 3D LAV and single-plane (r = 0.98; 95% CI = 0.94-0.97) and biplane (r = 0.97; 95% CI = 0.96-0.98) 2D LAVs.

CONCLUSION

Left atrial diameters and area measurements were poor predictors of 3D LAV, especially in the enlarged left atria. Therefore, these parameters can be misleading in assessing the severity of left atrial dilatation. Two-dimensional LAVs are accurate in estimating 3D LAV. The small additional accuracy obtained by using the biplane instead of the single-plane area-length method, and the fact that the biplane method is more technically demanding and time consuming, may allow the use of the area-length for routine clinical use.

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.

Review: Cardioprotective effects of telmisartan in uncomplicated and complicated hypertension

The development of angiotensin II receptor blockers (ARB) as a new class of drugs for the management of hypertension has elicited the attention of many clinicians worldwide with the aim of improving blood pressure (BP) control as well as cardiovascular protection.AmongARB telmisartan has been shown to be characterised by an antihypertensive efficacy fully covering the 24-hour period, thereby allowing to antagonise the adverse effects of early morning BP rise on cardiovascular risk. Other specific effects of the drug are represented by its favourable metabolic profile (particularly on insulin sensitivity) and neutral effects on sympathetic cardiovascular function.These properties are coupled with cardioprotective effects, documented by the evidence that the drug: 1) is effective in favouring the regression of cardiac and vascular organ damage, 2) reduces arterial stiffness and improves vascular distensibility and 3) reverses the endothelial dysfunction typical of the hypertensive state particularly when complicated by renal failure, diabetes, obesity or metabolic syndrome. Several of these properties can account for the results of the ONgoing Telmisartan Alone and in combination with Ramipril Global Endpoint Trial (ONTARGET), documenting the beneficial effects on the drug on cardiovascular morbidity and mortality.

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.

Structural and functional remodeling of the left atrium: clinical and therapeutic implications for atrial fibrillation

Left atrial (LA) structural and functional remodeling reflects a spectrum of pathophysiological changes that have occurred in response to specific stressors. These changes include alterations at the levels of ionic channels, cellular energy balance, neurohormonal expression, inflammatory response, and physiologic adaptations. There is convincing evidence demonstrating an important pathophysiological association between LA remodeling and atrial fibrillation (AF). Measures that will prevent, attenuate, or halt these processes of LA remodeling may have a major public health impact with respect to the epidemic of AF. In this review, we describe the mechanisms involved in LA remodeling and highlight the existing and potential therapeutic options for its reversal, and implications for AF development.

Assessment of Atrial Function

This article discusses the traditional and more recent echocardiographic measures that have been employed to evaluate atrial function. Conventional parameters commonly used and reported in the literature include the study of the various phases of atrial activity using atrial volume measurements, the peak A wave velocity, its velocity time integral (VTI) and the fraction of atrial contribution (all obtained from transmitral flow), as also the atrial ejection force. Newer parameters for atrial function assessment include Doppler tissue imaging (DTI) including segmental atrial contractility using colour Doppler tissue imaging (CDTI) and estimates of atrial strain and strain rate.

Noninvasive assessment of left atrial function by strain rate imaging in patients with hypertension: a possible beneficial effect of renin-angiotensin system inhibition on left atrial function

Renin-angiotensin system (RAS) inhibitors are likely to reduce the development of atrial fibrillation by preventing atrial fibrosis. Strain rate (SR) imaging is a novel echocardiographic technique to quantify left atrial (LA) function. However, it has not been determined whether SR imaging is applicable for detection of LA dysfunction in hypertensive (HT) patients. We used SR imaging to assess alteration in LA function in HT patients and its modification by RAS inhibitors. SR imaging was performed in 80 HT patients and 50 age-matched normotensive (NT) subjects. HT patients were divided into two groups according to left ventricular hypertrophy (LVH) and LA dilatation. Peak SR was measured at each LA segment (septal, lateral, posterior, anterior, and inferior) and mean peak systolic SR (SR-LAs) was calculated by averaging data in each segment. Mean SR-LAs levels in the dilated LA group (1.97+/-0.45 s(-1), n=25) and non-dilated LA group (2.15+/-0.57 s(-1), n=55) were significantly (p<0.05) lower than that in NT subjects (2.53+/-0.71 s(-1)). Irrespective of the presence or absence of LVH, mean SR-LAs in HT patients was lower than that in NT subjects. When RAS inhibitors were used, the mean SR-LAs level in the non-dilated LA group was equivalent to that in NT subjects. In HT patients, mean SR-LAs, an index of LA reservoir function, decreases before development of LA enlargement and LVH. Treatment with RAS inhibitors appears to preserve LA reservoir function in HT patients without dilated LA. SR imaging can detect LA dysfunction in HT patients and is useful for evaluation of the therapeutic benefit on LA reservoir function.

Effective treatment of hypertension by AT(1) receptor antagonism: the past and future of telmisartan

Lowering blood pressure is the most effective treatment method to ensure a reduction in the total risk for cardiovascular morbidity and mortality. The renin-angiotensin system plays an important role in volume homeostasis and blood pressure regulation and is a target for several groups of pharmaceutical agents. Angiotensin II receptor blockers represent the newest class of antihypertensive compounds. They prevent the binding of angiotensin II to the subtype 1 receptor (AT(1)), which is believed to mediate most of the physiological actions relevant to the regulation of blood pressure. Telmisartan, a widely used AT(1) receptor antagonist, is a highly selective compound with high potency, a long duration of action and a tolerability profile similar to placebo. Numerous randomized clinical trials and community-based studies have demonstrated that oral telmisartan and combinations of telmisartan with hydrochlorothiazide are at least as effective in lowering blood pressure as all other hypertensive medications. This has been demonstrated in different populations of adult patients with mild-to-moderate essential hypertension, including patients with coexisting Type 2 diabetes, metabolic syndrome or renal impairment. Several large-scale, long-term, clinical endpoint studies are in progress to assess the beneficial effects of telmisartan on hypertension-related end-organ damage in patients at high risk of renal, cardiac and vascular damage whose blood pressure is well controlled. The most recent data from clinical trials and latest research regarding telmisartan will be reviewed in this article.