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.     

Risks for atrial fibrillation and congestive heart failure in patients >/=65 years of age with abnormal left ventricular diastolic relaxation

We sought to determine the risk for the first episodes of atrial fibrillation (AF) and congestive heart failure (CHF) in a cohort of patients aged >/=65 years who had abnormal left ventricular (LV) diastolic relaxation. Records were reviewed for all residents of Olmsted County, Minnesota, who had >/=1 transthoracic echocardiogram performed at the Mayo Clinic between 1990 and 1998, and who were in sinus rhythm and did not have a history of AF, CHF, valvular or congenital heart disease, permanent pacemaker, or stroke. Of 994 patients who qualified and had LV diastolic function assessment, abnormal LV relaxation was identified in 569 (57%), 105 of whom (18%) developed a first episode of AF or CHF over a mean follow-up of 4.0 +/- 2.7 years. Age (p <0.0001), history of myocardial infarction (p <0.0001), history of diabetes mellitus (p = 0.041), electrocardiographic LV hypertrophy (p = 0.0223), and indexed left atrial (LA) volume (p = 0.0003) were independent predictors. A stepwise increase in age-adjusted risk was evident when stratified by tertiles of indexed LA volume (<27 ml/m(2); 27 to 37 ml/m(2); >37 ml/m(2)). Compared with patients with normal LV diastolic function (n = 148, 15%), the risks for first episodes of AF or CHF were not different in those with abnormal diastolic relaxation if LA volume was <27 ml/m(2) (p = 0.303). In conclusion, these data suggest the presence of a wide spectrum of risks for AF or CHF in the elderly who have abnormal LV diastolic relaxation, with the highest risks evident in those with the largest left atria. When LA volume was <27 ml/m(2), however, the risks for these events were not different from those with normal LV diastolic function.     

Increased left atrial volume index is an independent predictor of raised serum natriuretic peptide in patients with suspected heart failure but normal left ventricular ejection fraction: Implication for diagnosis of diastolic heart failure

BACKGROUND: Left atrial volume index (LAVI) is increasingly recognised as a relatively load-independent marker of left ventricular (LV) filling pressures. We assessed the capacity of LAVI to predict LV diastolic dysfunction in comparison with N-terminal pro B-type natriuretic peptide (NTproBNP) in patients with suspected heart failure and a normal ejection fraction (EF). METHODS: 137 patients with suspected heart failure (HF), referred from the community for echocardiography, prospectively underwent Doppler echocardiography, LAVI and NTproBNP estimation. Raised LAVI and reduced LV systolic function were defined as >26 ml/m2 and LV EF <50% respectively. RESULTS: Of 137 patients, 21 were excluded (2 with significant mitral valve disease and 19 with atrial fibrillation). Of the remaining 116 subjects, 92 showed normal LV systolic function. The univariate predictors of serum log NTproBNP were age (p < 0.001), LA dimension (p = 0.001), LAVI (p < 0.001), A wave (p = 0.001), E:A (p = 0.07) and septal wall thickness (p = 0.004). However on multivariate analysis, LAVI was found to be the most consistent and significant predictor of NTproBNP. The area under the curve of the receiver operating characteristic (ROC) curve for NTproBNP in detecting patients with LVEF > or = 50% and LAVI >26 ml/m2 was 0.81 (p < 0.0001) and for patients with LAVI > 26 ml/m2 with and without LVEF > or = 50% was 0.82 (p < 0.0001). CONCLUSION: This data confirms that LAVI on resting echocardiography, specifically in patients with suspected HF and normal LV systolic function is a powerful independent predictor of LV diastolic dysfunction as predicted by serum NTproBNP. In a population with a high suspicion of diastolic heart failure, LAVI may significantly contribute to diagnostic precision.     

Left ventricular longitudinal shortening in patients with aortic stenosis: relationship with symptomatic status

BACKGROUND AND AIM OF THE STUDY: Symptomatic status in aortic stenosis is not always related to hemodynamic severity as estimated by the aortic valve effective orifice area (AVA), and other factors may be involved. It has been seen previously that, whilst ejection fraction is preserved, left ventricular (LV) longitudinal shortening may be selectively decreased in aortic stenosis, and hypothesized that this might be a marker of subendocardial ischemia as subendocardial myocardial fibers are oriented longitudinally. The present study examined the possible relationship between LV longitudinal shortening and symptoms in patients with aortic stenosis. METHODS: Relevant clinical and echocardiographic variables, including the percentage of LV longitudinal shortening, were measured in 131 consecutive patients with at least moderate aortic stenosis (AVA <1.5 cm2). RESULTS: Symptoms were found in 106 patients (exertional dyspnea 93%, resting dyspnea 25%, angina 57%, syncope 27%). Compared with asymptomatic patients, symptomatic patients had a smaller AVA (0.91 +/- 0.27 versus 1.13 +/- 0.20 cm2; p < 0.001), a lower LV longitudinal shortening (19 +/- 13 versus 28 +/- 9%; p = 0.01), and higher incidence of coronary artery disease (52 versus 20%, p < 0.008). Other variables significantly associated with symptoms included age, previous myocardial infarction, obesity, indexed AVA, LV mass index, LV ejection fraction, cardiac index, energy loss index, and valvular resistance. However, in multivariate analysis, the only variables independently associated with symptomatic status were patient age (p = 0.03), indexed AVA (p = 0.006), and LV longitudinal shortening (p = 0.04). The combination of indexed AVA with LV longitudinal shortening resulted in an improvement of the performance for the prediction of symptoms. CONCLUSION: These results show that LV longitudinal shortening is more closely associated with changes in symptomatic status than other currently used indices of LV systolic function. As such, it probably more closely reflects alterations in subendocardial myocardial function.     

Left atrial volume index in patients with asymptomatic severe aortic stenosis

BackgroundThe proper timing for aortic valve surgery in the asymptomatic patient with severe aortic stenosis (AS) remains challenging. The aim of this study was to determine the left atrial volume index (LAVI) in asymptomatic patients with severe AS in comparison to symptomatic severe AS patients and its relation to the degree of left ventricular (LV) hypertrophy and tissue Doppler measures of LV diastolic function.MethodsThirty-four patients with severe AS and preserved LV function, divided into two groups were studied. Group I comprised 17 patients with symptomatic severe AS, and Group II comprised 17 patients with asymptomatic severe AS. Echocardiographic assessment of LV dimension, function, and calculation of LV mass were done. LA volume index was obtained by the biplane Simpson method. Transmitral E, A diastolic velocities, deceleration time (DT) and E/A ratio were measured. Peak S′, early (E′) and late (A′) diastolic velocities of the lateral mitral annulus were measured by tissue Doppler imaging.ResultsLAVI was significantly higher in symptomatic compared to asymptomatic patients with severe AS (p < 0.0001). LAVI with a cutoff point of 39.5 ml/m² was a predictor of symptoms in patients with severe AS yielded an area under the curve of 0.958, P < 0.0001, with a sensitivity of 94% and specificity of 89%. LAVI had a significant positive correlation with left ventricular mass (p < 0.014), right ventricular systolic pressure (RVSP) (p < 0.009), mitral peak E (p < 0.025), and E/E′ (p < 0.008). Multiple linear regression analysis revealed that LV mass (p < 0.0001) and E/E′ (p < 0.0001) were the independent predictors of increased LAVI in severe AS.ConclusionLeft atrial volume index can predict symptoms in patients with asymptomatic severe AS. Left ventricular mass and E/E′ were the independent predictors of increased LAVI.     

Angiotensin-converting enzyme polymorphisms and their potential impact on left ventricular myocardial geometry after aortic valve surgery

BACKGROUND AND AIM OF THE STUDY: Genetic variants of the angiotensin-converting enzyme (ACE) cascade may influence left ventricular myocardial mass (LVMM) regression after aortic valve surgery. Postoperative long-term changes in LV indices were investigated in patients with asymptomatic aortic regurgitation (AR) and symptomatic aortic stenosis (AS) and related to alleles of ACE polymorphisms. METHODS: A total of 96 patients was included in the study, 21 with class IIa AR (22%) and 75 with class I AS (78%) recommendations for surgery. Patients were evaluated for demographic risk factors and underwent a thorough clinical examination including 3-D cardiac imaging by ultrafast-computed tomography. Genomic DNA was isolated for genotyping. RESULTS: AR patients were younger (55.8 +/- 8.9 versus 64 +/- 9.1 years, p = 0.0014), had a larger body surface area (1.92 +/- 0.21 versus 1.82 +/- 0.19 m2, p = 0.039), and were more likely to be asymptomatic (myocardial infarction, p = 0.04; syncope, p = 0.0099; thromboembolism, p = 0.03; NYHA class IV, p = 0.04). Postoperatively, the reduction in absolute LVMM (from 297.1 +/- 52.6 to 190.1 +/- 57.1 g versus 214.4 +/- 55.7 to 143.8 +/- 40.0 g; pT = 0.0000001) and indexed LVMM (from 156.0 +/- 31.7 to 99.3 +/- 28.4 g/m2 versus 118.7 +/- 28.3 to 79.3 +/- 20.6 g/m; pT = 0.0000001) over time was more significant in AR patients, but never reached normal values. Enforced ACE inhibitor medication resulted in significantly higher postoperative indexed LVMM differences in homozygote DD patients compared to AR patients with II/ID alleles of ACE 16 ins/del polymorphism. CONCLUSION: AR patients showed a statistically significant decrease in absolute/indexed LVMM during follow up, but never achieved LV mass recovery compared to standard values or to values in patients undergoing aortic valve replacement for AS. The benefits of ACE inhibitors were observed among AR patients with homozygote DD alleles of ACE 16 ins/del polymorphism.     

Effects of quinapril on left atrial structural remodeling and arterial stiffness

Left atrial (LA) enlargement, left ventricular (LV) diastolic dysfunction, and increased arterial stiffness are all associated with adverse cardiovascular outcomes. The rate, magnitude, and concordance of modifiability of these risk markers have not been well characterized. Twenty-one patients (mean age 69 +/- 8 years; 52% women) with isolated diastolic dysfunction and indexed LA volumes > or =32 ml/m(2) were randomly assigned to receive either quinapril at a target dose of 60 mg/day or matching placebo for 12 months. Echocardiographic maximum LA volume and LV diastolic function and arterial stiffness by the augmentation index were measured at baseline and 6 and 12 months. Analysis was based on intention to treat. Baseline characteristics were comparable between the treatment (n = 9) and placebo (n = 12) groups. The mean reduction in LA volume of 4.2 +/- 7.8 ml/m(2) in the quinapril group was significant (p = 0.01) compared with the increase in LA volume in the placebo group (5.5 +/- 8.1 ml/m(2)). This represents a relative improvement of 9.7 ml/m(2). Change in LV filling pressure in terms of E/e' and diastolic function grade did not reach significance. A reduction in the augmentation index was associated with a decrease in indexed LA volume (odds ratio 11, p = 0.046), independent of changes in systolic blood pressure. In conclusion, LA structural remodeling appeared reversible with quinapril, which occurred in parallel with an improvement in arterial stiffness but independent of blood pressure changes.     

Usefulness of left atrial volume index to predict heart failure hospitalization and mortality in ambulatory patients with coronary heart disease and comparison to left ventricular ejection fraction (from the Heart and Soul Study)

The predictive value of left atrial (LA) dilatation in ambulatory adults with coronary artery disease is not known. It was hypothesized that echocardiographic LA volume index (LAVI) predicts heart failure (HF) hospitalization and mortality with similar statistical power as left ventricular ejection fraction (LVEF) in ambulatory adults with coronary artery disease. We measured LAVI in 935 adults without atrial fibrillation, atrial flutter, or significant mitral valve disease in the Heart and Soul Study. LAVI was calculated using the biplane method of disks. Outcomes included HF hospitalization and mortality. Logistic regression odds ratios (ORs) were calculated and adjusted for age, demographics, medical history, left ventricular mass, diastolic function, and LVEF. Mean LAVI was 32 +/- 11 ml/m2, and mean LVEF was 62 +/- 10%. Sixty-six patients (7%) had LAVI >50 ml/m2. There were 108 HF hospitalizations and 180 deaths at 4.3 years of follow-up. C statistics calculated as the area under the receiver-operator characteristic curve were the same (0.60) for LAVI and LVEF in predicting mortality. The unadjusted OR for HF hospitalization was 4.4 for LAVI >50 ml/m2 and 5.3 for LVEF <45% (p <0.001). In those with normal LVEF, the ORs for LAVI >50 ml/m2 were 5.2 for HF hospitalization (p <0.0001) and 2.5 for mortality (p = 0.006). After multivariate adjustment, LAVI >50 ml/m2 was predictive of HF hospitalization (OR 2.4, p = 0.02), and LAVI >40 ml/m2 was predictive of mortality (OR 1.9, p = 0.005). In conclusion, LAVI had similar predictability as LVEF for HF hospitalization and mortality in ambulatory adults with coronary artery disease.     

Long-term prognostic significance of left atrial volume in acute myocardial infarction

OBJECTIVES: The aim of this study was to evaluate the significance of increased left atrial (LA) volume determined within the first 48 h of admission as a long-term predictor of outcome in patients with acute myocardial infarction (MI). BACKGROUND: The LA volume reflects left ventricular (LV) diastolic properties. Whereas other LV Doppler diastolic characteristics are influenced by acute changes in LV function, LA volume is stable and reflects diastolic properties before MI. METHODS: Clinical and echocardiographic parameters were prospectively collected in 395 consecutive patients with acute MI. Patients with LA volume index (LAVI) >32 ml/m(2) (normal + 2 standard deviations) were compared with those with LAVI <==32 ml/m(2). Independent clinical and echocardiographic prognostic risk factors for five years' mortality were determined by the Cox proportional hazard model. RESULTS: Left atrial volume index >32 ml/m(2) was found in 63 patients (19%) who had a higher incidence of congestive heart failure on admission (24% vs. 12%, p < 0.01), a higher incidence of mitral regurgitation, increased LV dimensions, and reduced LV ejection fraction when compared with patients with LAVI <==32 ml/m(2). Their five-year mortality rate was 34.5% versus 14.2% (p < 0.001). Significant independent risk predictors of five years' mortality were age (10 years) (odds ratio [OR] 1.45; 95% confidence interval [CI]1.14 to 1.86), Killip class >/=2 on admission (OR 2.30; 95% CI 1.29 to 4.09), LAVI >32 ml/m(2) (OR 2.22; 95% CI 1.25 to 3.96), diabetes (OR 1.94; 95% CI 1.15 to 3.28), and LV restrictive filling pattern (OR 1.89; 95% CI 1.09 to 3.31). CONCLUSIONS: In patients with acute MI, increased LA volume, determined within the first 48 h of admission, is an independent predictor of five-year mortality with incremental prognostic information to clinical and echocardiographic data.     

Left atrial volume: predictor of atrial fibrillation in patients with degenerative mitral regurgitation

BACKGROUND AND AIM OF THE STUDY: In patients with mitral regurgitation (MR) due to degenerative mitral valve prolapse (MVP), preoperative atrial fibrillation (AF) has been identified as an independent predictor of survival after surgery for MR. Thus, the determinants of preoperative AF may have critical implications to evaluate the timing of mitral valve repair. The study aim was to investigate the role of left atrial (LA) volume in predicting preoperative AF in patients with severe MR due to degenerative MVP. METHODS: Sixty-six patients with severe degenerative MR (regurgitant volume > or =60 ml, regurgitant fraction > or =50%, effective regurgitant orifice area > or =0.4 cm(2)) in sinus rhythm (SR) at diagnosis and conservatively managed were eligible for the study. Complete two-dimensional (2-D) echocardiographic and Doppler measurements, including the measurement of maximum LA volume, were performed in all patients. RESULTS: During follow up under conservative management (18.1+/-4.8 months), eight patients (12%) experienced conversion to AF, and 58 remained in SR. The mean LA dimension was 4.0+/-0.5 cm in patients with SR, and 5.1+/-0.8 cm in those who developed AF (p <0.0001). The mean LA volume and LA volume index (indexed to body surface area) were 95 +/-23 ml and 60+/-14 ml/m(2) respectively in patients with SR, and 166+/-66 ml and 104+/-42 ml/m(2) respectively in those who developed AF (both p <0.0001). The optimal cut-off value for LA volume to predict AF conversion was 117.5 ml (sensitivity 88%, specificity 83%), and for LA volume index was 75 ml/m(2) (sensitivity 88%, specificity 88%). CONCLUSION: LA volume measurement should be considered in patients with degenerative severe MR diagnosed in SR. A LA volume index > or =75 ml/m(2) reflects the risk of subsequent AF, and patients should be closely monitored.     

Severe isolated aortic stenosis with normal left ventricular systolic function and low transvalvular gradients: pathophysiologic and prognostic insights

BACKGROUND AND AIM OF THE STUDY: A significant proportion of patients with severe valvular aortic stenosis (AS) and preserved left ventricular (LV) systolic function have low transvalvular gradients. The study aim was to determine the mechanisms and outcome of patients with this hemodynamic profile of AS. METHODS: Among 1,679 patients who underwent transthoracic echocardiography for the evaluation of AS at the authors' institution, 215 (105 females, 110 males; mean age: 77 +/- 10 years) had isolated AS (mean aortic valve area index 0.39 +/- 0.1 cm2/m2), normal sinus rhythm and normal LV ejection fraction. The mean follow up was 23 +/- 12 months, and the end-points were mortality, aortic valve replacement (AVR), or mortality or AVR. RESULTS: Forty-seven patients had a transvalvular mean gradient (MG) <30 mmHg (MG(low)) and 168 had MG > or = 30 mmHg (MG(high)). Compared to MG(high), the MG(low) group had a higher prevalence of hypertension, lower LV end-diastolic volume index (47 +/- 9 versus 56 +/- 12 ml/m2, p <0.0001), lower LV stroke vol-ume index (37 +/- 12 versus 41 +/- 11 ml/beat, p <0.0002), a lesser severity of stenosis (aortic valve area index 0.37 +/- 0.09 versus 0.46 +/- 0.09 cm2/m2, p <0.0001) and a higher systemic vascular resistance (2163 +/- 754 versus 1879 +/- 528 dyne cm s(-5). The LV end-diastolic volume index, systemic vascular resistance and energy loss index were predictors of MG <30 mmHg (OR = 0.30, 95% CI, 0.12, 0.62; OR = 3.05, 95% CI, 1.71, 6.26; and OR = 6.76, 95% CI, 3.44,15.38, respectively). MG <30 mmHg (MGhigh) was associated with almost 50% lower referral to surgery and a two-fold increase in preoperative mortality. CONCLUSION: In severe AS with a normal LV ejection fraction, MG <30 mmHg is related to a lesser severity of stenosis, a smaller LV volume, a lower flow rate and a higher systemic vascular resistance. Compared to the MG(high) group, these patients were less frequently referred to surgery and had a higher mortality.     

Determinants of left ventricular mass in aortic stenosis

BACKGROUND AND AIM OF THE STUDY: There are many possible determinants of left ventricular (LV) mass, including the angiotensin-converting enzyme (ACE) genotype, which have rarely been compared in aortic stenosis (AS). The study aim was to investigate these determinants in patients with all grades of AS. METHODS: Transthoracic echocardiography and an analysis of ACE genotype was performed in 91 patients with aortic valve thickening and a peak aortic velocity >2.0 m/s. RESULTS: Univariate relationships were identified between LV mass index and effective orifice area (R = 0.22), and peak transaortic pressure difference (R = 0.36). LV mass index was similar for the ACE-II (152+/-37 g/m2), ACE-ID (145+/-46 g/m2) and ACE-DD (161+/-56 g/m2) genotypes. LV mass index was significantly greater in males (162+/-52 gm/m2) than in females (137+/-38 gm/m2; p = 0.014). The multivariate determinants varied according to the grade of AS: diastolic blood pressure (p = 0.028) in mild stenosis; peak transaortic pressure difference (p = 0.03) in moderate stenosis; and peak transaortic pressure difference (p <0.0001) and gender (p = 0.02) in severe stenosis. LV hypertrophy was present in 15 of 24 patients (63%) with mild AS, in 21 of 27 (78%) with moderate AS, and 32 of 40 (80%) with severe AS. CONCLUSION: LV hypertrophy is common, even in mild AS, when it is independently related only to the systemic blood pressure. This suggests that antihypertensive agents should be considered early in the natural history of AS.     

Early predictors of alterations in left atrial structure and function related to left ventricular dysfunction in asymptomatic patients with hypertension

Our aim was to investigate the relationships between left atrial (LA) structural and functional changes and left ventricular (LV) dysfunction related to LV pressure overload in asymptomatic patients with hypertension. One hundred and twenty-six asymptomatic patients with hypertension and LV ejection fraction (EF) ≥60% were studied. Conventional, pulsed and tissue Doppler, and two-dimensional speckle-tracking echocardiography (2DSTE) were performed to seek the independent determinants for alterations in LA structure and function. LA volume index (LAVI) correlated with age, body mass index (BMI), end-diastolic ventricular septal thickness (VSth), end-diastolic LV posterior wall thickness, relative LV wall thickness (RWT), LV mass index, peak A velocity of transmitral flow, E/e’, and peak systolic and early diastolic LA strains and strain rates. Peak LA strain during ventricular systole (S-LAs) correlated with age, BMI, heart rate (HR), end-systolic LV diameter, LAVI, VSth, RWT, LVEF, e’, E/e’, peak systolic LV radial strain, and peak early diastolic LV longitudinal strain rate. Multivariate regression analyses indicated that LV mass index, peak A velocity, E/e’, and S-LAs are defined as strong predictors related to LAVI, and that BMI, HR, LAVI, and peak systolic LV radial strain are defined as strong predictors related to S-LAs. In conclusion, 2DSTE demonstrated that alterations in LA structure and function are mainly associated with LV diastolic and systolic dysfunction, respectively, in preclinical patients with hypertension.     

Left atrial velocity vector imaging for the detection and quantification of left ventricular diastolic function in type 2 diabetes

Left ventricular (LV) diastolic dysfunction (DD) is diagnosed by Doppler echocardiography (DE) and Tissue Doppler imaging (TDI). Velocity vector imaging (VVI) evaluates myocardial deformation (strain). We studied left atrial (LA) deformation and volumes by VVI in relation to established Doppler-derived indices of LV diastolic function in diabetic patients. MATERIAL: Using DE and TDI , 87 patients (males 49%; age 60+/-7 years) with type 2 diabetes mellitus were classified as having no (n=60), mild (n=13) or moderate (n=14) DD. RESULTS: LA volume was larger in moderate (72.3+/-22.4 ml) than in mild DD (58.8+/-16.1 ml; p=0.01) and no DD (57.9+/-16.0 ml; p=0.01). LA roof strain distinguished no DD from mild and moderate DD (p=0.0073). Systolic LA strain correlated to total emptying fraction (r=0.70, p<0.0001), and inversely to LA volume (r=-0.35, p=0.0009). A cross-validated analysis of no versus mild or moderate DD expressed by LA strain revealed a positive predictive value of 48% and negative of 84%. CONCLUSION: LA strain by VVI is impaired in patients with type 2 diabetes mellitus and mild or moderate LV DD. LA strain seems of value in distinguishing normal from abnormal diastolic function. VVI offers new information on regional LA function and LA volumes but has too limited discriminative power to detect early LV DD.     

Wall stress modulates brain natriuretic peptide production in pressure overload cardiomyopathy

OBJECTIVES: We postulated that both diastolic and systolic load modulate B-type natriuretic peptide (BNP) production in human pressure overload hypertrophy/failure. BACKGROUND: In isolated myocytes, diastolic stretch induces BNP messenger ribonucleic acid expression. However, the mechanism of the BNP release in human hypertrophy remains controversial. METHODS: In 40 patients with symptomatic aortic stenosis (AS), left ventricular (LV) performance and systolic and diastolic wall stress were calculated from combined invasive and echocardiographic data. Plasma BNP was determined by the rapid point-of-care bedside analyzer (Biosite Triage, Biosite Diagnostics Inc., San Diego, California). RESULTS: A significant relationship was observed between plasma BNP and pulmonary capillary wedge pressure (p < 0.001), fractional shortening (p = 0.001), and aortic valve area (p = 0.006). Furthermore, a significant correlation was noted between BNP and LV mass index (p = 0.005) as well as between BNP and markers of diastolic load such as LV end-diastolic wall stress (p = 0.011), indexed LV end-diastolic volume (p < 0.001), and isovolumic relaxation time (p = 0.02). Preoperative BNP levels were elevated in patients with AS compared with patients without AS. Plasma BNP was higher in AS patients with impaired versus normal preload reserve (297 +/- 56 pg/ml vs. 168 +/- 44 pg/ml; p = 0.017) and in AS patients with clinical deterioration after valve replacement compared with those without (399 +/- 82 pg/ml vs. 124 +/- 41 pg/ml; p = 0.011). CONCLUSIONS: In patients with AS, BNP appears to be regulated not only by systolic but also by diastolic load. This supports the hypothesis that myocardial stretch modulates BNP production in human pressure overload hypertrophy/failure.     

Effect of haemodialysis on left atrial mechanical function in patients with chronic renal failure

OBJECTIVE: The aim of this study was to investigate the potential effects of haemodialysis on left atrial (LA) mechanical functions in patients with chronic renal failure. METHODS: Thirty-two patients with chronic renal failure (mean age 42.8 +/- 19.6 years) were included in this study. LA volumes were determined echocardiographically at the time of mitral valve opening (maximal,Vmax), at the onset of atrial systole (p wave at the electrocardiography = Vp) and at the mitral valve closure (minimal, Vmin) according to the biplane area-length method in apical 4-chamber and 2-chamber view. All volumes were corrected to the body surface area, and the following left atrial emptying functions were calculated. LA passive emptying volume = Vmax - Vp, LA passive emptying fraction = LA passive emptying volume/Vmax. Conduit volume = LV stroke volume-(Vmax - Vmin), LA active emptying volume = Vp Vmin. LA active emptying fraction = LA active emptying volume/Vp, LA total emptying volume = (Vmax - Vmin), LA total emptying fraction = LA total emptying volume/Vmax. RESULTS: Mean fluid removal was 1,875 +/- 812 milliliter.There was no difference between in the LA passive emptying volume before and after dialysis (10.83 +/- 7.44 vs. 11.47 +/- 7.73 cm3/m2, p > 0.05). Conduit volume (from 15.30 +/- 10.68 to 10.31 +/- 6.83 cm3/m2, p < 0.05), LA active emptying volume (from 12.61 +/- 6.39 to 9.25 +/- 4.40 cm3/m2, p < 0.005), LA total emptying volume (from 23.44 +/- 8.52 to 20.72 +/- 8.58 cm3/m2, p < 0.05), LA maximal volume (from 39.44 +/- 14.07 to 28.89 +/- 11.80 cm3/m2, p < 0.001), LA minimal volume (from 15.99 +/- 9.70 to 8.17 +/- 4.52 cm3/m2, p < 0.001), and the volume at the onset of atrial systole (from 28.61 +/- 10.36 to 17.42 +/- 7.20 cm3/m2, p < 0.001) decreased significantly after the haemodialysis session, whereas LA passive emptying fraction (from 0.27 +/- 0.14 to 0.38 +/- 0.14%, p < 0.001), LA active emptying fraction (from 0.46 +/- 0.18 to 0.53 +/- 0.17%, p < 0.05), LA total emptying fraction (from 0.61 +/- 0.14 to 0.72 +/- 0.09%, p < 0.001) increased significantly after haemodialysis. CONCLUSION: The results of this study suggest that left atrial mechanical functions improve after haemodialysis in patients with chronic renal failure.     

Left ventricular midwall mechanics in subjects with aortic stenosis and normal systolic chamber function

BACKGROUND AND AIM OF THE STUDY: Endocardial indices of left ventricular (LV) systolic function overestimate myocardial performance in hypertrophic left ventricles. Midwall fractional shortening (mFS) is a more reliable index of systolic performance. Aortic stenosis (AS) is a common cause of LV hypertrophy (LVH), but midwall mechanics in this condition have not been analyzed. Also, a tendency towards hyperdynamic LV chamber function has been reported in women with AS in comparison with men, but whether there exist gender-related discrepancies in midwall performance is not known. METHODS: The study group included 147 patients with AS and normal chamber systolic function. LV diameters and thicknesses, LV mass, relative wall thickness (RWT), endocardial fractional shortening, stroke volume, ejection fraction (EF), mFS and stress-corrected mFS were determined. RESULTS: Patients with AS showed depressed mFS (16.2 +/- 2.5% versus 18.8 +/- 2.4%, p <0.0001) and stress-corrected mFS (84.3 +/- 13.8% versus 100.0 +/- 12.6%, p <0.0001) when compared to controls. The subset with moderate AS had lower mFS (15.9 +/- 2.0%) than those with mild AS (16.9 +/- 2.4%), and further depression was present in subjects with severe AS (13.8 +/- 2.2%, p <0.0001). A similar trend was observed for stress-corrected mFS (mild AS, 88.5 +/- 13.3%; moderate AS, 82.0 +/- 11.5%; severe AS, 71.2 +/- 12.0%, p <0.0001). Multivariate analysis identified RWT as the best predictor of mFS and stress-corrected mFS. Logistic regression showed that depressed stress-corrected mFS was independently associated with the presence of symptoms. Endocardial fractional shortening and EF were increased in women compared to men, but there were no gender-related differences in mFS (16.2 +/- 2.5% versus 16.1 +/- 2.4%, p = 0.84) and stress-corrected mFS (84.0 +/- 14.1% versus 84.5 +/- 13.5%, p 0.82). CONCLUSION: Aortic stenosis is associated with depression in LV midwall mechanics. Systolic midwall performance reduces as the severity of valve disease increases, and this relationship is mediated by parallel changes in LV geometry.     

Doppler echocardiographic assessment of hemodynamic progression of valvular aortic stenosis over time: comparison between aortic valve resistance and valve area.

BACKGROUND: Doppler-derived aortic valve resistance (AVR), i.e. the ratio between pressure gradient and flow rate, has been proposed as an alternative parameter to valve area (AVA) for assessing the hemodynamic severity of aortic stenosis (AS). There are no data on the evaluation of hemodynamic progression of AS using AVR. METHODS: Forty-five adult patients (24 women and 21 men, mean age 72 +/- 10 years) with AS were followed up for 18 months (range 6 to 45 months) with serial Doppler-derived AVR (Isaaz, JACC 1991; 18: 1661) and AVA (continuity equation). Rates of change of AVR and AVA over time were indexed for year of follow-up; furthermore, variations of these parameters during follow-up were expressed as percent change from baseline. RESULTS: During the follow-up period, AVA decreased from 0.74 +/- 0.28 to 0.6 +/- 0.17 cm2 (p < 0.05), with a rate of change of -0.1 +/- 0.13 cm2/year; AVR increased from 349 +/- 187 to 462 +/- 180 dyne/s/cm-5 (p < 0.05), with a rate of change of 79 +/- 69 dyne/s/cm-5/year. Variations observed in AVR, expressed as percent change from baseline, were larger than those observed in AVA (51 +/- 62% versus -16.5 +/- 15%). AVR percent change from baseline significantly correlated with AVA percent change from baseline (r = 0.83, p < 0.05). During follow-up, 6 patients showed no change in AVA: AVR was unchanged in 3 and increased in the remaining 3 patients (6, 11 and 58%, respectively), indicating a progression of AS severity that could not be appreciated from AVA alone. CONCLUSIONS: Serial changes in AVR, as assessed by Doppler echocardiography, significantly correlate with changes in AVA. Thus, the noninvasive assessment of AVR may be utilized in the evaluation of hemodynamic progression of AS and, in conjunction with AVA, may also provide complementary information for the management of these patients.     

左心房容积指数在评价急性心肌梗死病例预后中的价值

目的探讨左心房容积指数(LAVI)与急性心肌梗死(AMI)预后之间的关系。方法选取收治的AMI病例312例,于急性期行超声心动图检查,测左心房容积、左心室的收缩和舒张功能,左心房容积通过体表面积来校正,将观察者按LAVI分为两组,即LAVI>30ml/m2共168例(占54%)和≤30ml/m2共144例(占46%)两组,自病例入院开始观察,若病例死亡观察结束。结果在平均36个月(0~60月)的观察随访过程中,共有50例死亡,其中LAVI≤30ml/m2死亡14例,LAVI>30ml/m2者死亡36例,P<0.001。LAVI是AMI病例预后的一个重要和独立危险因素(LAVI每增加1ml/m2,相对危险度为1.04,95%可信区间为1.03~1.06,P<0.001)。结论LAVI增大是AMI病例预后的一个独立危险因素,能够提供关于心肌梗死病例预后的信息,它和射血分数一起可以大大提高对心肌梗死病例预后的预测。     

Left atrial enlargement and NT-proBNP as predictors of sudden cardiac death in patients with heart failure

AIMS: The identification of valuable markers of sudden cardiac death (SCD) in patients with established HF remains a challenge. We sought to assess the value of clinical, echocardiographic and biochemical variables to predict SCD in a consecutive cohort of patients with heart failure (HF) due to systolic dysfunction. METHODS: A cohort of 494 patients with established HF had baseline echocardiographic and NT-proBNP measurements and were followed for 942+/-323 days. RESULTS: Fifty patients suffered SCD. Independent predictors of SCD were indexed LA size>26 mm/m2 (HR 2.8; 95% CI 1.5-5.0; p=0.0007), NT-proBNP>908 ng/L (HR 3.1; 95% CI 1.5-6.7; p=0.003), history of myocardial infarction (HR 2.3; 95% CI 1.3-4.1; p=0.007), peripheral oedema (HR 2.1; 95% CI 1.1-3.9; p=0.02), and diabetes mellitus (HR 1.9; 95% CI 1.1-3.3; p=0.03). NYHA functional class, left ventricular ejection fraction and glomerular filtration rate were not independent predictors of SCD in this cohort. Notably, the combination of both LA size>26 mm/m2 and NT-proBNP>908 ng/L increased the risk of SCD (HR 4.3; 95% CI 2.5-7.6; p<0.0001). At 36 months, risk of SCD in patients with indexed LA size26 mm/m2 and NT-proBNP>908 ng/L reached 25% (p<0.0001). CONCLUSIONS: Among HF patients, indexed LA size and NT-proBNP levels are more useful to stratify risk of SCD than other clinical, echocardiographic or biochemical variables. The combination of these two parameters should be considered for predicting SCD in patients with HF.