Prognostic value of left atrial volume in patients who underwent dobutamine stress echocardiography for known or suspected coronary artery disease

Impact of right atrial enlargement on clinical outcome in patients with atrial fibrillation

Background

Left atrial (LA) remodeling is associated with adverse cardiovascular events, including heart failure (HF) and stroke in patients with atrial fibrillation (AF). However, there are limited data on the value of right atrial (RA) remodeling in this population. We investigated the prognostic role of RA enlargement in patients with non-valvular AF.

Methods and results

We analyzed 254 consecutive patients (age = 69 ± 12years, male:female = 165:89, mean left ventricular ejection fraction = 58.0 ± 7.2%) with non-valvular AF who underwent two-dimensional echocardiography from a single center. RA and LA volumes were measured from apical views and indexed to the body surface areas (right atrial volume index [RAVI] and left atrial volume index [LAVI]) and RAVI > 30mL/m2 and LAVI > 34mL/m2 were considered as enlarged. The relationship between RA enlargement and composite clinical outcome of hospitalization for HF (HHF), stroke, systemic embolism, or death from any cause was assessed. Right atrial (RA) enlargement was associated with older age and more frequent prevalence of persistent or permanent AF. During a median follow-up of 47.1 months, 77 patients (30%) had experienced primary composite outcome. In a multivariable model, RA enlargement, but not LA enlargement, was independently associated with adverse clinical outcomes even after adjusting for clinical and echocardiographic factors {adjusted hazard ratio [HR], 1.90 [95% confidence interval (CI), 1.14–3.18], p = 0.014 for primary composite outcome; adjusted HR, 2.70 [95% CI, 1.27–5.67], p = 0.001 for HHF or all cause death}.

Conclusion

RA enlargement was independently associated with an increased risk of HF, stroke, systemic embolization or death in patients with non-valvular AF, suggesting that RA volume can be helpful in assessing future cardiovascular risk in this population.

Relationship of left atrial expansion index to exercise tolerance, pretest probability of restenosis, and positive predictive value of treadmill test in coronary artery disease

BACKGROUND

Whether left atrial (LA) expansion index is associated with coronary restenosis, and exercise capacity (EC) reduction in coronary artery disease has not been established.

METHODS

This study analyzed 342 consecutive patients who had received a coronary stent implant. A treadmill exercise test (TET) was administered in all participants. The LA expansion indices were measured immediately before and after TET. Maximal EC measured on a breath-by-breath basis by a metabolic cart with gas analyzers and recorded as metabolic equivalent task. All patients with positive TET results received angiography, and those with restenosis received complete revascularization by either percutaneous coronary intervention (PCI) or bypass surgery. The LA expansion index and EC before and 1 month after PCI were then compared.

RESULTS

Out of 342 patients, 74 had positive TET results, and 54 had restenosis in angiography. Low LA expansion index was associated with poor EC. In patients with LA expansion index > 200%, only 5% had restenosis with 38.5% positive predictive value (PPV) of TET. In patients with LA expansion index < 100%, however, 64.3% had restenosis with 94.7% PPV of TET. Restenosis induced low pre-TET LA expansion index and further decline during TET. The LA expansion index significantly (P .001) improved from 133 ± 64% before PCI to184 ± 86% after PCI, and the improvement corresponded with EC recovery. A 10% reduction in LA expansion index was associated with a 15% increase in pretest probability of restenosis.

CONCLUSION

The LA expansion index is associated with EC, pretest probability of restenosis, and PPV of TET. Revascularization improves both EC and LA expansion index.

Clinical significance of left atrial volume in clinical outcomes of heart transplant recipients

Background

Left atrial volume (LAV) is surgically kept enlarged in heart transplant (HT) recipients. On the other hand, LAV has been known an independent predictor of various cardiovascular diseases and is associated with exercise capacity of HT recipients. Thus, we evaluated the hypothesis that LAV is still associated with clinical outcomes in HT recipients whose left atria are artificially enlarged.

Methods

Clinical outcomes over 5 years after HT were retrospectively evaluated in 35 HT recipients who had a LAV measurement with echocardiography at 1 year after HT at the University of Cincinnati Medical Center. The LAV was derived from a stacked disc method using apical 4 and 2 chamber views.

Results

The average LAV normalized to body surface area was 38.3 ± 9.9 ml/m² (mean ± SD) at 1 year after HT. Two deaths and one drop-out occurred during 5-year follow up. A total of 552 cardiac symptom-related hospitalizations occurred in the recipients. The average time to first hospitalization was 166 ± 279 days and average number of hospitalizations of each recipient was 15 ± 16. The indexed LAV failed to correlate with the time to first hospitalization and number of hospitalizations of each recipient (Spearman’s p-value; 0.141 and 0.519 respectively). When the patients were divided to groups of large LAV (n = 17) and small LAV (n = 18) using the cut off value of the mean LAV, no significant difference was noted in mortality, hospitalization, and new onset of atrial fibrillation between the groups.

Conclusions

Although our study is limited by a retrospective study design and relatively small number of patients, our results implicate that LAV is not significantly associated with clinical outcomes in HT recipients over 5 years after HT.

Sex-specific biatrial volumetric measurements obtained with use of multidetector computed tomography in subjects with and without coronary artery disease

Atrial volumetric measurement has proven clinical implications. Advances in cardiac imaging, notably the precision enabled by multidetector computed tomography (MDCT), herald the need for new criteria of what constitutes normal volumetric measurements. With use of 64-slice MDCT, we compared the atrial volumes in healthy individuals with those in individuals with coronary artery disease. By means of manual segmentation, we measured biatrial volume in 686 participants who underwent retrospective electrocardiographic-gated MDCT angiographic evaluation. The study population included a control group of 203 persons with no cardiac abnormalities, and a study group of 483 patients with obstructive coronary artery disease. All variables were compared between men and women and between the groups. We found a significant difference in left atrial end-systolic and end-diastolic volumes between men and women in the control group (P <0.05); however, right atrial volumes were similar. In comparison with the entire control group, the coronary artery disease group had significantly higher left atrial volume, significantly lower right atrial stroke volume, and significantly lower biatrial ejection fraction, except for left atrial ejection fraction in men. Right atrial volume and left atrial stroke volume were not significantly different. The results imply that a sex-specific reference value is necessary for left atrial volumetric evaluation, and that left atrial volume and biatrial ejection fraction (excluding left atrial ejection fraction in men) might be useful during diagnosis and prognosis in patients who have coronary artery disease.

Effect of left atrium volume on patients' prognosis following acute myocardial infarction

Evaluating left atrium volume is a good way to estimate prognosis in acute myocardial infarction patients because it indicates to time and severity of diastolic dysfunction and longer-term results of acute myocardial infarction. The present study aims at evaluating the effect of left atrium volume on patients' prognosis following acute myocardial infarction. This is a cohort study conducted on 100 patients who were admitted with acute myocardial infarction. They were studied for 9 months and their one-month mortality rate was evaluated. The patients were studied considering demographic factors, risk factors, mechanical and arrhythmic complications and echocardiography indexes such as systolic and diastolic functions and left atrium volume. It was seen that mortality (27.3%, 6.22) in patients with atrium index > 32 mL m(-2) is more than cases with lower atrium index (1.3%, 1.78) (p = 0.001). There was not any meaningful difference in mortality rate of the patients considering age and gender (p > 0.05). This study indicated to lack of any meaningful difference in patients' mortality rate in terms of hypertension, diabetes, smoking and dyslipidemia. But, mortality rate was significantly higher in MI as a result of elevated-ST, diastolic dysfunction, restrictive pattern, ejection fraction of left atrium < 40%, left atrium volume index > 32 mL m(-2). High volume left atrium independently refers to bad prognosis in patients with acute myocardial infarction which is confirmed with outcome clinical predictors and common echocardiography indexes even following modification.

Left atrial size and risk for all-cause mortality and ischemic stroke

BACKGROUND

Limited data are available on the relation between left atrial size and outcome among patients referred for clinically indicated echocardiograms. Our aim was to assess the association of left atrial size with all-cause mortality and ischemic stroke in a large cohort of patients referred for echocardiography.

METHODS

Left atrial diameter was measured in 52 639 patients aged 18 years or older (mean age 61.8 [standard deviation (SD) 16.3] years; 52.9% men) who underwent a first transthoracic echocardiogram for clinical reasons at our institution between April 1990 and March 2008. The outcomes were all-cause mortality and nonfatal ischemic stroke.

RESULTS

Based on the criteria of the American Society of Echocardiography, 50.4% of the patients had no left atrial enlargement, whereas 24.5% had mild, 13.3% had moderate and 11.7% had severe left atrial enlargement. Over a mean follow-up period of 5.5 (SD 4.1) years, 12 527 patients died, and 2314 patients had a nonfatal ischemic stroke. Cumulative 10-year survival was 73.7% among patients with normal left atrial size, 62.5% among those with mild enlargement, 54.8% among those with moderate enlargement and 45% among those with severe enlargement (p < 0.001). After adjustment in multivariable Cox proportional hazard analysis, left atrial diameter remained a predictor of all-cause mortality in both sexes (hazard ratio [HR] per 1-cm increment in left atrial size 1.17, 95% confidence interval [CI] 1.12-1.22, p < 0.001 in women, and HR 1.09, 95% CI 1.05-1.13, p < 0.001 in men) and of ischemic stroke in women (HR 1.25, 95% CI 1.14-1.37, p < 0.001).

INTERPRETATION

Left atrial diameter has a graded and independent association with all-cause mortality in both sexes and with ischemic stroke in women.

Ventricular response to stress predicts outcome in adult patients with a systemic right ventricle

BACKGROUND

Previous studies demonstrated that ventricular response to stress cardiovascular magnetic resonance (CMR) is frequently abnormal in patients with a systemic right ventricle (RV). However, the clinical implications of these findings remained unknown. We sought to evaluate whether abnormal response to stress CMR predicts adverse outcome in patients with a systemic RV.

METHODS

Thirty-nine adult patients (54% male; mean age 26, range 18-65 years) with a systemic RV underwent stress CMR to determine the response of RV volumes and ejection fraction (EF). During follow-up, cardiac events, defined as hospitalization for heart failure, cardiac surgery, aborted cardiac arrest, or death, were recorded. The prognostic value of an abnormal response to stress, defined as lack of a decrease in RV end-systolic volume (ESV) or lack of an increase in RV EF, was assessed.

RESULTS

We frequently observed an abnormal response to stress, as RV ESV did not decrease in 17 patients (44%), and RV EF did not increase in 15 patients (38%). After a mean follow-up period of 8.1 years, 8 (21%) patients had reached the composite end point. The inability to decrease RV ESV during stress was predictive for cardiac events with a hazard ratio of 2.3 (95% CI 1.19-88.72, P = .034), as was the inability to increase RV EF with a hazard ratio of 2.3 (95% CI 1.31-81.59, P = .027).

CONCLUSIONS

Stress CMR potentially has important prognostic value in patients with a systemic RV. Patients with a systemic RV who show abnormal cardiac response to stress have a substantially higher risk of adverse outcome.

Customized exercise echocardiography: beyond detection of coronary artery disease

Exercise echocardiography has been established as a reliable diagnostic tool for assessment of myocardial ischemia. However, more recent advances in its technique have expanded its routine clinical use to include quantification of exercise-induced diastolic dysfunction, exercise-induced pulmonary hypertension, and dynamic assessment of mitral and aortic valve function. The indications for exercise echocardiography have increased to include cardiac symptoms such as exertional dyspnea, fatigue, and limited exercise capacity. In light of its expanded capability for evaluating cardiovascular function, we believe that exercise echocardiography should be utilized in a new paradigm of personalized cardiology, in which we regularly investigate individual patient symptoms for endpoints beyond critical myocardial ischemia, for example, exercise-induced pulmonary hypertension. We refer to this refocused use of exercise echocardiography as "customized exercise echocardiography." In this review article, we present current scientific evidence to support our proposed role and discuss the logistical requirements for proper test performance of customized exercise echocardiography.

Velocity vector imaging to quantify left atrial function

The aim of our study was to assess the feasibility of a new image analysis, velocity vector imaging (VVI), in the assessment of left atrial volumes (LAV) and left atrial ejection fraction (LAEF). We retrospectively analysed 100 transthoracic echocardiographic findings in 71 men, and 29 women (mean age 57 ± 19.8 years). Two subgroups of patients were defined: (1) with left ventricular (LV) EF > 50%, and (2) LV EF < 50%. For the VVI method of indexed LAV assessment we used the apical four-chamber view. From the displacement of LA endocardial pixels time–volume curves were extracted which provided automatically data regarding indexed maximum LAV (LAVImax), indexed minimum LAV (LAVImin), and LAEF. LAVs and LAEF by 2-dimensional echocardiograhy (2DE) were measured by Simpson’s biplane disc summation method. Comparing LAVImax, LAVImin, and LAEF by VVI versus 2DE in the total study population, we found significant correlations: r = 0.94, P < 0.0001, r = 0.94, P < 0.0001, r = 0.79, P < 0.0001, respectively. In addition, LAVImax ≥ 40 ml/m² was 94% sensitive and 72% specific, LAVImin ≥ 27 ml/m² was 90% sensitive and 86% specific, and LAEF < 30% was 80% sensitive and 96% specific for the detection of LV systolic dysfunction. There were highly significant inverse associations of LAVImax and LAVImin to LVEF. LAEF was also significantly related to LV systolic function. When comparing the time required for VVI and 2DE measurements, VVI led to 62% reduction in the measurement time. In conclusion, VVI is a feasible method for the assessment of LAVs and LAEF. It provides close agreement with that measured by conventional 2DE Simpson’s biplane method with significant time saved.