Left atrial function assessed by real-time 3-dimensional echocardiography is related to right ventricular systolic pressure in chronic mitral regurgitation

Cardiac Imaging for the Assessment of Left Atrial Mechanics Across Heart Failure Stages

The left atrium (LA) is emerging as a key element in the pathophysiology of several cardiac diseases due to having an active role in contrasting heart failure (HF) progression. Its morphological and functional remodeling occurs progressively according to pressure or volume overload generated by the underlying disease, and its ability of adaptation contributes to avoid pulmonary circulation congestion and to postpone HF symptoms. Moreover, early signs of LA dysfunction can anticipate and predict the clinical course of HF diseases before the symptom onset which, particularly, also applies to patients with increased risk of HF with still normal cardiac structure (stage A HF). The study of LA mechanics (chamber morphology and function) is moving from a research interest to a clinical application thanks to a great clinical, prognostic, and pathophysiological significance. This process is promoted by the technological progress of cardiac imaging which increases the availability of easy-to-use tools for clinicians and HF specialists. Two-dimensional (2D) speckle tracking echocardiography and feature tracking cardiac magnetic resonance are becoming essential for daily practice. In this context, a deep understanding of LA mechanics, its prognostic significance, and the available approaches are essential to improve clinical practice. The present review will focus on LA mechanics, discussing atrial physiology and pathophysiology of main cardiac diseases across the HF stages with specific attention to the prognostic significance. Imaging techniques for LA mechanics assessment will be discussed with an overlook on the dynamic (under stress) evaluation of the chamber.

Echocardiographic predictors of exercise induced pulmonary hypertension in patients with asymptomatic moderate to severe mitral regurgitation and preserved left ventricular ejection fraction

BACKGROUND

The significant role of mitral regurgitation (MR) in development of pulmonary hypertension (PH) has been proved in previous studies. Experts suggest systolic pulmonary arterial pressure (SPAP) ⩾60 mmHg during exercise as a significant threshold of negative prognostic value in patients with MR.

PURPOSE

The aim of this study was to evaluate the changes of SPAP and to ascertain the determinants of exercise induced pulmonary hypertension (EIPH) in patients with asymptomatic primary MR.

METHODS

We performed a prospective study that included 50 patients with asymptomatic primary moderate to severe MR with preserved left ventricular ejection fraction (LV EF ⩾60%) at rest. They were divided into two groups according to the presence (PH group; n = 13) or absence (non-PH group; n = 37) of EIPH. Rest and stress (bicycle ergometry) echocardiography and speckle-tracking offline analysis were performed.

RESULTS

An increment of SPAP from rest to peak stress was higher in PH group (p < 0.001). Multivariate regression analysis showed that MR effective regurgitation orifice area (EROA; p = 0.008) and regurgitant volume (RVol; p = 0.006) contributed significantly to SPAP at rest. Higher increment of MR EROA during stress and worse parameters of LV diastolic function at rest (E, A, E/e') correlated significantly with higher SPAP during peak stress and they had a major role in predicting EIPH according to univariate logistic regression analysis. In ROC analysis SPAP >33.1 mmHg at rest could predict EIPH with 84.6% sensitivity and 87.1% specificity (95%CI 0.849-1.000; p < 0.001).

CONCLUSIONS

Parameters of MR severity (EROA and RVol) were significant determinants of SPAP at rest, while the increment of MR EROA during stress and parameters of resting LV diastolic function were the best predictors of significant EIPH.

Impact of Left Ventricular Diastolic Property on Left Atrial Function from Simultaneous Left Atrial and Ventricular Three-Dimensional Echocardiographic Volume Measurement

Simultaneous left atrial (LA) and left ventricular (LV) 3-dimensional (3D) echocardiographic volume measurements enable the quantifying of precise LA function, by virtue of their independence on any geometric assumption and capability of measurement for net LA conduit volume. We sought to elucidate the impact of conventional Doppler LV diastolic property on LA volume and function derived from this method. Our study subjects consisted of 381 patients who underwent 3D echocardiography. From LA time-volume curve, maximum and minimum volume index (VI) and VI before atrial contraction (LAVIpre-c) were determined; subsequently, active emptying volume was calculated as LAVIpre-c - minimum LAVI. From LA and LV volume measurement, conduit volume was calculated as LV stroke VI - (maximum LAVI - minimum LAVI). LA volume increased depending on the severity of diastolic dysfunction. Compared with patients with normal diastolic function, LA booster pump function, as the contribution of active emptying volume to LV filling, was higher in those with mild diastolic dysfunction. Additionally, it gradually decreased as diastolic dysfunction was advanced from mild to moderate and moderate to severe degree (23.2 ± 15.5%, 29.5 ± 15.1%, 25.1 ± 16.2%, 14.9 ± 14.1%, respectively; p <0.001). Contrarily, conduit contribution was significantly higher in patients with severe diastolic dysfunction than in those with mild diastolic dysfunction; furthermore, conduit function tended to increase, reciprocally to booster pump function, as diastolic dysfunction grade was advanced (39.1 ± 28.8%, 36.8 ± 26.2%, 42.7 ± 25.6%, 52.9 ± 26.2%, respectively; p = 0.034). In conclusion, simultaneous LA and LV volumetric analyses through 3D echocardiography clearly demonstrate the characteristic LA functional alterations following LA dilation caused by LV diastolic dysfunction.

Left atrial volume and function in dogs with naturally occurring myxomatous mitral valve disease

OBJECTIVE

Myxomatous mitral valve disease (MMVD) induces progressive left atrial (LA) enlargement. The LA modulates left ventricular filling and performance through its reservoir, conduit, and contractile function. Assessment of LA size and function may provide valuable information on the level of cardiac compensation. Left atrial function in dogs with naturally occurring MMVD remains largely unexplored. The objective of this study was to evaluate LA volume and function in dogs with naturally occurring MMVD.

ANIMALS

This prospective study included 205 client-owned dogs of different breeds, 114 healthy dogs, and 91 dogs with MMVD of different disease severities.

METHODS

Using two-dimensional echocardiography, the biplane area-length method was applied to assess LA volume and calculate volumetric indices of LA reservoir, conduit, and contractile function.

RESULTS

Left atrial volume and LA stroke volume increased, whereas LA reservoir and contractile function decreased with increasing disease severity. A maximal LA volume <2.25mL/kg was the optimal cut off identified for excluding congestive heart failure in dogs with chronic MMVD with a sensitivity of 96% and a specificity of 100%. An active LA emptying fraction <24% and/or a LA expansion index <126% were suggestive of congestive heart failure in dogs with chronic MMVD with a sensitivity of 77% and a specificity of 89% and a sensitivity of 82% and a specificity of 82%, respectively.

CONCLUSION

Dogs with MMVD appear to have larger LA volumes with poorer LA function. Deteriorating LA function, characterized by a decreasing reservoir and active contractile function, was evident in dogs with MMVD with increasing disease severity.

Independent predictors of developing pulmonary hypertension in heart failure with reduced versus preserved ejection fraction

OBJECTIVES

To investigate the different clinical and echocardiographic predictors of evolving PH in patients with heart failure with and without reduced ejection fraction.

METHODS AND RESULTS

The study included 153 heart failure patients with reduced ejection fraction (HFrEF) (n = 89) and preserved ejection fraction (HFpEF) (n = 64) both of which were subdivided into 2 subgroups according to the presence of PH. All patients were subjected to detailed clinical assessment and full transthoracic echocardiogram. There were significant differences between the 2 HFrEF subgroups regarding systolic BP, presence of diabetes, dyslipidemia, diuretics usage, all LV parameters, LAD, LAV and LAV indexed to BSA, E/A ratio, DT and severity of TR. Using multivariate analysis, the presence of diabetes (P = 0.04), diuretics usage (P = 0.04), LAV (P = 0.007) and TR grade (P < 0.001) were significant independent predictors for the development of PH among HFrEF patients. There were significant differences between the 2 HFpEF subgroups regarding presence of hypertension, diuretics usage, LAD, LAA, TR severity. Using multivariate analysis, only diuretics usage (P = 0.02) and TR grade (P < 0.0001) were significant independent predictors for the development of PH among HFpEF patients.

CONCLUSION

Neither the decrease in EF among HFrEF patients nor the DD grade in HFpEF patients act as independent predictor for evolving PH. Common independent predictors for evolving PH in both HFrEF and HFpEF patients are TR grade and use of diuretics. Other independent predictors in HFrEF and not HFpEF patients are the presence of diabetes and increased LAV.

Management of pulmonary hypertension in left heart disease

Pulmonary hypertension (PH) due to left heart disease is classified as group II according to the Dana Point classification, which includes left ventricular systolic and/or diastolic left heart failure, and left-sided valvular disease. PH due to left heart disease is the most common cause and when present, especially with right ventricular dysfunction, is associated with a worse prognosis. Left heart disease with secondary PH is associated with increased left atrial pressure, which causes a passive increase in pulmonary pressure. Passive PH could be superimposed by an active protective, and in some patients by an ‘out of proportion’, elevated precapillary pulmonary vasoconstriction and vascular remodelling which leads to greater or lesser further increase of the pulmonary artery pressure. In this review, epidemiological and pathophysiologic mechanisms for the development of group II PH are summarized. The conflicting data about the haemodynamic and possible parameters to diagnose passive versus reactive and ‘out of proportion’ PH are presented. The different therapeutic concepts, along with novel treatment strategies, are reviewed in detail and critically discussed regarding their effectiveness and safety.

Left atrium reverse remodeling in patients with mitral valve stenosis after percutaneous valvuloplasty: a 2- and 3-dimensional echocardiographic study

INTRODUCTION AND OBJECTIVES

The left atrium is clinically relevant in patients with mitral valve stenosis. The objective of this study was to analyze the effects of percutaneous balloon valvuloplasty on left atrium volumes and the left atrium emptying fraction in symptomatic mitral valve stenosis patients using 2-dimensional and real-time 3 -dimensional transthoracic echocardiography.

METHODS

We carried out a prospective study of 28 consecutive symptomatic mitral valve stenosis patients, aged 22-72 (39 [11.5]) years, 24/28 (85.6%) women, who underwent to percutaneous balloon valvuloplasty between March 2009 and May 2011. Patients underwent 2- and 3-dimensional transthoracic and transesophageal echocardiography (atrial fibrillation) and invasive mitral valve area measurement. Echocardiographic analysis was performed before, 72 h after and 12 months after percutaneous balloon valvuloplasty. The following parameters were analyzed: a) mitral valve area (2-dimensional planimetry, pressure half-time, 3-dimensional echocardiography, invasive hemodynamic measurement); b) indexed left atrium maximum and indexed minimum volumes, and c) left atrium emptying fraction.

RESULTS

The 3-dimensional parameters of the mitral valve stenosis patients before and 72 h and 12 months after percutaneous balloon valvuloplasty were as follows: a) mitral valve area: 0.9 (0.1) cm(2); 1.8 (0.2) cm(2) (P<.001); 1.7 (0.2) cm(2) (P<.001); b) left atrium maximum volumes: 49.9 (12) mL/m(2); 42 (11.4) mL/m(2) (P<.001); 40.3 (10.2) mL/m(2) (P<.001), and c) left atrium emptying fraction: 30.1 (9.4%); 40.6 (7.4%) (P<.001); 44.1 (8%) (P<.001), respectively.

CONCLUSIONS

In symptomatic mitral valve stenosis patients who underwent percutaneous balloon valvuloplasty analysis by 2- and 3-dimensional echocardiography, improvements in left atrium reverse remodeling and left atrium emptying fraction were observed 72 h and 12 months after the procedure.

Determinants and prognostic significance of exercise pulmonary hypertension in asymptomatic severe aortic stenosis

BACKGROUND

Recent studies emphasized the usefulness of exercise stress echocardiography in asymptomatic patients with aortic stenosis. Nevertheless, the additive value of exercise pulmonary hypertension (Ex-PHT) in such patients remains unexplored. We therefore aimed to identify the determinants and to test the impact on outcome of Ex-PHT in asymptomatic patients with severe aortic stenosis.

METHOD AND RESULTS

Asymptomatic patients with severe aortic stenosis (n=105; aortic valve area <0.6 cm(2)/m(2); age, 71±9 years; male, 59%) and preserved left ventricular systolic function (ejection fraction ≥55%) were prospectively submitted to exercise stress echocardiography. Resting PHT and Ex-PHT were defined as a systolic pulmonary arterial pressure >50 and >60 mm Hg, respectively. Ex-PHT was more frequent than resting PHT (55% versus 6%; P<0.0001). On multivariable logistic regression, the independent predictors of Ex-PHT were male sex (odds ratio, 4.3; P=0.002), resting systolic pulmonary arterial pressure (odds ratio, 1.16; P=0.002), exercise indexed left ventricular end-diastolic volume (odds ratio, 1.04; P=0.026), exercise e'-wave velocity (odds ratio, 1.35; P=0.047), and exercise-induced changes in indexed left atrial area (odds ratio, 1.36; P=0.006). Ex-PHT was associated with reduced cardiac event-free survival (at 3 years, 22±7% versus 55±9%; P=0.014). In a multivariable Cox proportional hazards model, Ex-PHT was identified as an independent predictor of cardiac events (hazard ratio, 1.8; 95% confidence interval, 1.0-3.3; P=0.047). When exercise-induced changes in mean aortic pressure gradient were added to the multivariable model, Ex-PHT remained independently associated with reduced cardiac event-free survival (hazard ratio, 2.0; 95% confidence interval, 1.1-3.6; P=0.025).

CONCLUSIONS

In asymptomatic patients with severe aortic stenosis, the main determinants of Ex-PHT are male sex, resting systolic pulmonary arterial pressure, and exercise parameters of diastolic burden. Moreover, Ex-PHT is associated with a 2-fold increased risk of cardiac events. These results strongly support the use of exercise stress echocardiography in asymptomatic aortic stenosis.

Left atrial function in cats with left-sided cardiac disease and pleural effusion or pulmonary edema

BACKGROUND

Congestive heart failure (CHF) in cats with left-sided heart disease is sometimes manifest as pleural effusion, in other cases as pulmonary edema.

HYPOTHESIS

Those cats with pleural effusion have more severe left atrial (LA) dysfunction than cats with pulmonary edema.

ANIMALS

30 healthy cats, 22 cats with pleural effusion, and 12 cats with pulmonary edema. All cats were client owned.

METHODS

Retrospective study. Measurements of LA size and function were made using commercial software on archived echocardiograms. Cases were identified through searches of medical records and of archived echocardiograms for cats with these conditions.

RESULTS

There was no difference (P = .3) in LA size between cats with pleural effusion and cats with pulmonary edema. Cats with pleural effusion had poorer (P = .04) LA active emptying and increased (P = .006) right ventricular (RV) diameter when compared with cats with pulmonary edema and healthy cats. Cats that exhibited LA active emptying of <7.9%, total emptying of <13.6% (diameter) or <19.4% (area), or RV diameter of >3.6 mm were significantly (P < .001) more likely to manifest pleural effusion.

CONCLUSIONS AND CLINICAL IMPORTANCE

Poorer LA function and increased RV dimensions are associated with pleural effusion in cats with left-sided heart disease.

Left atrial thrombus and prognosis after anticoagulation therapy in patients with atrial fibrillation

BACKGROUND

Anticoagulation therapy reduces the risk of thromboembolic events by two-thirds in patients with atrial fibrillation (AF). The prevalence of left atrial thrombus (LAT) in AF patients with anticoagulation therapy has not been fully investigated.

PURPOSE

To investigate the prevalence of LAT and its impact on the outcomes in patients with nonvalvular AF after anticoagulation therapy.

METHODS

This study consisted of 231 patients with nonvalvular AF who had transthoracic (TTE) and transesophageal echocardiographic (TEE) examinations more than 3 weeks after anticoagulation therapy. The clinical and echocardiographic characteristics were evaluated.

RESULTS

LAT was observed in 13 (8.8%) of 148 patients with sub-therapeutic anticoagulation, and in 3 (3.6%) of 83 patients with sufficient anticoagulation. The presence of LAT was associated with higher CHADS(2) score, decreased LA volume changes and the presence of spontaneous echocardiographic contrast (SEC) in patients with sub-therapeutic anticoagulation. Patients with LAT after sufficient anticoagulation were male with permanent AF who had decreased left ventricular systolic and diastolic function and dilated LA on TTE and SEC, and reduced appendage flow velocity on TEE. Patients with LAT had worse cardiovascular outcomes compared with those without LAT (p=0.02).

CONCLUSIONS

We demonstrated that LAT was a univariate risk factor associated with worse cardiovascular outcomes, which was observed in 8.8% of patients with sub-therapeutic anticoagulation and 3.6% of patients with sufficient anticoagulation.

Relation of left atrial dysfunction to pulmonary artery hypertension in patients with aortic stenosis and left ventricular systolic dysfunction

Pulmonary artery hypertension (PAH) increases mortality in patients with severe aortic stenosis. We hypothesized that left atrial (LA) dysfunction would be related to PAH in patients with severe aortic stenosis complicated by left ventricular (LV) systolic dysfunction. The data from 70 patients with severe aortic stenosis and LV systolic dysfunction were analyzed. From the transmitral flow, the peak early (E) and late (A) diastolic velocities were obtained. From the pulmonary vein flow, the peak S-wave, D-wave, and reversed atrial wave velocities were determined. The right ventricular systolic pressure was measured in 50 patients and averaged 38 +/- 13 mm Hg. Patients with PAH (n = 19) presented with greater LV diameters, E/A ratio, E-wave velocity, LV mass index, reversed atrial wave velocity, and LA volume (p <0.05) and lower S/D ratio and total and active LA emptying fractions (p <0.05). Simple linear regression analysis revealed that the LA volumes and total and active LA emptying fractions displayed the strongest correlations with the right ventricular systolic pressure. Multiple regression analysis revealed that the minimum LA volume (r = 0.61, p = 0.0001) independently correlated with the right ventricular systolic pressure, irrespective of the aortic valve (AV) area or gradient. In patients who underwent an echocardiographic examination >or=1 month after AV replacement, LA function had improved significantly. The degree of improvement was related to the degree of recovery of the LV diastolic function and diameter. In conclusion, in patients with severe aortic stenosis and concomitant LV systolic dysfunction, the LA function parameters displayed the strongest correlations with the right ventricular systolic pressure, irrespective of the AV area or gradient and were impaired in patients with PAH. LA function recovered after AV replacement. Additional studies are warranted to determine the prognostic significance of LA function in this setting.

Exercise Pulmonary Hypertension in Asymptomatic Degenerative Mitral Regurgitation

Background— Current guidelines recommend mitral valve surgery for asymptomatic patients with severe degenerative mitral regurgitation and preserved left ventricular systolic function when exercise pulmonary hypertension (PHT) is present. However, the determinants of exercise PHT have not been evaluated. The aim of this study was to identify the echocardiographic predictors of exercise PHT and the impact on symptoms.

Methods and Results— Comprehensive resting and exercise transthoracic echocardiography was performed in 78 consecutive patients (age, 61±13 years; 56% men) with at least moderate degenerative mitral regurgitation (effective regurgitant orifice area =43±20 mm 2 ; regurgitant volume =71±27 mL). Exercise PHT was defined as a systolic pulmonary arterial pressure (SPAP) >60 mm Hg. Exercise PHT was present in 46% patients. In multivariable analysis, exercise effective regurgitant orifice was an independent determinant of exercise SPAP ( P <0.0001) and exercise PHT ( P =0.002). Resting PHT and exercise PHT were associated with markedly reduced 2-year symptom-free survival (36±14% versus 59±7%, P =0.04; 35±8% versus 75±7%, P <0.0001). After adjustment, although the impact of resting PHT was no longer significant, exercise PHT was identified as an independent predictor of the occurrence of symptoms (hazard ratio=3.4; P =0.002). Receiver-operating characteristics curves revealed that exercise PHT (SPAP >56 mm Hg) was more accurate than resting PHT (SPAP >36 mm Hg) in predicting the occurrence of symptoms during follow-up ( P =0.032).

Conclusions— Exercise PHT is frequent in patients with asymptomatic degenerative mitral regurgitation. Exercise mitral regurgitation severity is a strong independent predictor of both exercise SPAP and exercise PHT. Exercise PHT is associated with markedly low 2-year symptom-free survival, emphasizing the use of exercise echocardiography. An exercise SPAP >56 mm Hg accurately predicts the occurrence of symptoms.

Left atrial volume combined with atrial pump function identifies hypertensive patients with a history of paroxysmal atrial fibrillation

Identifying patients at high risk for the occurrence of atrial fibrillation is one means by which subsequent thromboembolic complications may be prevented. Left atrial enlargement is associated with progression of atrial remodeling, which is a substrate for atrial fibrillation, but impaired atrial pump function is also another aspect of the remodeling. Our objective was to differentiate patients with a history of paroxysmal atrial fibrillation using echocardiography. We studied 280 hypertensive patients (age: 66+/-7 years; left ventricular ejection fraction: 65+/-8%), including 140 consecutive patients with paroxysmal atrial fibrillation and 140 age- and sex-matched control subjects. Left atrial volume was measured using the modified Simpson method at both left ventricular end systole and preatrial contraction and was indexed to body surface area. Peak late-diastolic mitral annular velocity was measured during atrial contraction using pulsed tissue Doppler imaging as an atrial pump function. Left atrial volume index measured at left ventricular end systole had a 74% diagnostic accuracy and a 71% positive predictive value for identifying patients with paroxysmal atrial fibrillation; these values for the ratio of left atrial volume index at left ventricular end systole to the peak late-diastolic mitral annular velocity were 82% and 81%, respectively, and those for the ratio of left atrial volume index at preatrial contraction to the peak late-diastolic mitral annular velocity were 86% and 90%, respectively. In conclusion, left atrial size combined with atrial pump function enabled a more accurate diagnosis of a history of paroxysmal atrial fibrillation than conventional parameters.