Assessment of left atrial volume and mechanical function in ischemic heart disease: a multi slice computed tomography study

Left atrial strain quantified after myocardial infarction is associated with early left ventricular remodeling

BACKGROUND

Left ventricular remodeling (LVR) is common and associated with adverse outcome after ST-elevation myocardial infarction (STEMI). We aimed to investigate the association between left atrial (LA) mechanical function using speckle tracking imaging and early LVR at follow-up in STEMI patients.

METHODS

Baseline 3D thoracic echocardiograms were performed within 48 h following admission and at a median follow-up of 7 months after STEMI. A > 20% increase in the left ventricular (LV) end-diastolic volume compared to baseline at follow-up was defined as LVR. LA global longitudinal strain was evaluated for the reservoir, conduit, and contraction (LASct) phases.

RESULTS

A total of 121 patients without clinical heart failure (HF) were prospectively included, between June 2015 and October 2018 (age 58.3 ± 12.5 years, male 98 (81%)). Baseline and follow-up LV ejection fraction (LVEF) were 46.8% [41.0, 52.9] and 52.1% [45.8, 57.0] respectively (p < .001). Compared to other patients, those with LVR had significantly lower values of LASct at baseline (-7.4% [-10.1, -6.5] vs. -9.9% [-12.8, -8.1], p < .01), both on univariate and baseline LV volumes-adjusted analyses. Baseline LA strain for reservoir and conduit phases were not associated with significant LVR at follow-up. Intra- and interobserver analysis showed good reproducibility of LA strain.

CONCLUSIONS

Baseline LASct may help identifying patients without HF after STEMI who are at higher risk of further early LVR and subsequent HF and who may benefit from more intensive management.

Cardiac chamber volumes and left ventricular mass in people living with HIV and matched uninfected controls

OBJECTIVES

People living with HIV (PLWH) have increased risk of cardiovascular diseases compared with uninfected populations. We assessed structural cardiac abnormalities and their associated risk factors in well-treated PLWH and uninfected controls using multidetector computed tomography (MDCT).

METHODS

People living with HIV and age- and sex-matched uninfected controls underwent MDCT to determine left atrial volume (LAV), left ventricular diastolic volume (LVDV), right ventricular diastolic volume (RVDV) and left ventricular mass (LVM). All outcomes were indexed to body surface area (BSA) (LAVi, LVDVi, RVDVi and LVMi).

RESULTS

A total of 592 PLWH and 1184 uninfected controls were included in the study. PLWH had smaller mean (SD) LAVi [40 (8) vs. 41 (9) mL/m² ; P = 0.002] and LVDVi [61 (13) vs. 65 (14) mL/m² ; P < 0.001] but larger RVDVi [89 (18) vs. 86 (17) mL/m² ; P < 0.001] than uninfected controls. HIV was independently associated with 7 mL (95% CI: -10 to -3) smaller LVDV, and with 12 mL (95% CI: 8-16) larger RVDV, and 4 g (95% CI: 1-6) larger LVM after adjustment for cardiovascular risk factors and BSA. Large RVDV in PLWH was not associated with obstructive lung function.

CONCLUSIONS

HIV was independently associated with smaller LVDV and larger RVDV and LVM. Alterations in cardiac chamber volumes in PLWH were mainly minor. The clinical impact of these findings is uncertain, but it seems unlikely that alterations in cardiac chamber volumes explain the increased burden of cardiovascular disease previously observed in PLWH.

Prognostic Impact of Left Atrial Function Following Transcatheter Mitral Valve Repair

Background

Left atrial (LA) function predicts clinical outcome in a variety of cardiovascular diseases. However, limited data are available in the setting of mitral regurgitation. The aim of the present study was to assess potential changes in LA ejection fraction (LAEF) and its prognostic value in patients following transcatheter mitral valve repair using the MitraClip.

Methods and Results

A total of 88 consecutive patients undergoing MitraClip implantation with complete echocardiography at baseline and follow‐up between 3 and 6 months postprocedure were enrolled. LAEF improved in 58% of the population. Change in LAEF was associated with residual mitral regurgitation, residual transmitral gradient and left ventricular ejection fraction changes. Compared with their counterparts, patients with residual mitral regurgitation ≥grade 2 (change in LAEF, −6% [Interquartile [IQR], −9–1%] versus 4% [IQR, −5–15%]; P=0.05) and with residual transmitral gradient ≥5 mm Hg (change in LAEF, −2% [IQR, −9–9%] versus 5% [IQR, −4–16%]; P=0.03) showed a decline in LAEF, respectively. Furthermore, LAEF significantly correlated with changes in left ventricular ejection fraction (r=0.40; P=0.001). With regards to clinical outcome, heart failure symptoms as assessed by New York Heart Association class were more severe in patients with worsened LAEF at follow‐up. Finally, LAEF change was identified as an independent predictor of all‐cause mortality (hazard ratio, 0.94; 95% CI, 0.90–0.98 [P=0.008]).

Conclusions

The present analysis showed that changes in LA function in patients undergoing MitraClip implantation are associated with important measures including residual mitral regurgitation, elevated transmitral gradient, and left ventricular function. Importantly, LA function alterations represent a strong predictor for all‐cause mortality.

Cardiac ventricular sizes are reduced in patients with long-term, normoalbuminuric type 1 diabetes compared to the non-diabetic background population

AIMS

Type 1 diabetes entails increased cardiovascular morbidity and cardiac chamber sizes are associated with cardiovascular disease. The aim of this study was to compare cardiac chamber sizes in normoalbuminuric persons with type 1 diabetes to a background population without diabetes.

METHODS

In a cross-sectional study, we examined 71 normoalbuminuric persons with long-term type 1 diabetes without known cardiovascular disease using cardiac multi-detector computed tomography. Cardiac chamber sizes and left ventricular remodelling were compared to persons without diabetes from the Copenhagen General Population Study.

RESULTS

Participants were median (interquartile range) 54 (48-60) (type 1 diabetes) and 57 (50-64) (without diabetes) years old and 59% were men (both groups). Participants with type 1 diabetes had smaller left ventricular mass (-3.5 g/m², 95% confidence interval -5.8 to -1.3) and left (-4.0 mL/m², 95% confidence interval -6.9 to -1.0) and right (-11.7 mL/m², 95% confidence interval -15.4 to -7.9) ventricular volumes in multivariable analyses (adjusted for age, sex, body composition, blood pressure and antihypertensive medication), but no differences in atrial volumes.

CONCLUSION

Persons with long-term type 1 diabetes had smaller left ventricular mass and biventricular volumes, yet similar atrial sizes, compared to a background population without diabetes. These findings may reflect subclinical development of diabetic cardiomyopathy.

Left ventricular remodelling and cardiac chamber sizes in long-term, normoalbuminuric type 1 diabetes patients with and without cardiovascular autonomic neuropathy

AIMS

Type 1 diabetes is associated with increased cardiovascular (CV) morbidity and mortality, and cardiovascular autonomic neuropathy (CAN) is an important CV risk factor. The study aimed to explore associations between CAN and altered cardiac chamber sizes in persons with type 1 diabetes.

METHODS

This was a cross-sectional study of 71 asymptomatic, normoalbuminuric participants with long-term type 1 diabetes (39 with CAN, determined by >1 abnormal autonomic function test) examined with cardiac multi detector computed tomography scans, which allowed measurements of left ventricular mass and all four cardiac chamber volumes. Cardiac chambers were indexed according to body surface area (ml/m² or g/m²).

RESULTS

Persons with and without CAN had mean ± SD age of 57 ± 7 and 50 ± 8 years (p < 0.001) and diabetes duration of 36 ± 11 and 32 ± 9 years (p < 0.05), respectively. Increasing autonomic dysfunction, evaluated by decrease in heart rate variability during deep breathing (in beats per minute), was associated with larger right (-0.5, 95% CI -1.0 to -0.0, p < 0.05) and trend towards larger left (-0.4, 95% CI -0.8-0.0, p < 0.1) ventricular volumes in multivariable linear regression.

CONCLUSIONS

Our results suggest that impaired autonomic function may be associated with modest enlargement of ventricular volumes; this might be an early sign of progression towards heart failure.

Real-time three-dimensional echocardiography of left atrial volume and function in patients with severe multi-vessel coronary artery disease

PURPOSE

To evaluate the changes in left atrial (LA) volume and function in patients with severe multi-vessel coronary artery disease (CAD) by real-time three-dimensional echocardiography (RT-3DE).

METHODS

One hundred and eight subjects were stratified based on coronary angiography (CAG) imaging, comprising 48 patients with severe multi-vessel CAD, 31 patients with severe single-vessel CAD, and 29 controls. RT-3DE was performed in all groups. LA volume parameters were measured. LA ejection fractions (EF) and LA function index (LAFI) were also calculated.

RESULTS

There were no significant differences between the single-vessel CAD group and the control group, while LA passive emptying fraction (LAVpEF) was significantly reduced in the single-vessel CAD group. In the multi-vessel CAD group, LAVpEF and LAFI were lower, while LA presystolic volume (LAVpre) was prominently higher as compared with the other groups, and LA active emptying volume (LAVa) was higher than that in the control group (p < 0.05). Receiver-operating characteristic (ROC) analysis showed that the area under the curve (AUC) of LAVpEF was the largest parameter; the optimal cut-off value, AUC, sensitivity, and specificity were 0.50, 0.864, 93.7, and 72.4 %, respectively.

CONCLUSION

Specifically, conduit function reflects the early changes in LA function, and CAD damage is aggravated with increasing coronary lesions, whereas the booster pump function of severe multi-vessel CAD can increase in compensation. We speculate that LAVpEF may be the most ideal threshold for detecting and differentiating severe CAD patients from controls.

Significant reduction of left atrial volume concomitant with clinical improvement after percutaneous transluminal septal myocardial ablation for drug-refractory hypertrophic obstructive cardiomyopathy, and its precise detection with multidetector CT

Objective

In patients with hypertrophic obstructive cardiomyopathy (HOCM), left atrial (LA) volume measurement is very important to provide prognostic information. Recent studies demonstrated that multidetector CT (MDCT) is useful to assess the changes in LA volume. Our aim was to examine the utility of a follow-up cardiac MDCT for long-term evaluation of the effect of percutaneous transluminal septal myocardial ablation (PTSMA) on LA volume.

Methods

We studied a consecutive cohort of 20 patients with drug-refractory symptomatic HOCM after PTSMA. We evaluated LA volume analyses with cardiac MDCT on patients who underwent PTSMA as compared to echocardiography.

Results

Before PTSMA, 75% of all patients had heart failure-associated symptoms in the New York Heart Association functional class III/IV. All patients experienced relief from heart failure-associated symptoms after PTSMA. Cardiac MDCT showed significant reduction in the index of maximum LA volume during follow-up compared to before PTSMA in the same way as in echocardiography (93.6±34.1 mL/m² vs 82.6±35.3 mL/m², p=0.035). A Bland-Altman plot showed small mean differences and limits of agreement in the measurements of the index of maximum LA volume before and after PTSMA between echocardiography and MDCT.

Conclusions

The follow-up cardiac MDCT was a useful tool to evaluate the effectiveness of PTSMA on reduction of LA volume. Cardiac MDCT might provide comparable measurements of the LA volume in patients with drug-refractory symptomatic HOCM before and after PTSMA compared to echocardiography.

Assessment of left sided filling dynamics in diastolic dysfunction using cardiac computed tomography

BACKGROUND

Left ventricular (LV) diastolic dysfunction (DD) often accompanies coronary artery disease but is difficult to assess since it involves a complex interaction between LV filling and left atrial (LA) emptying.

OBJECTIVE

To characterize simultaneous changes in LA and LV volumes using cardiac computed tomography (CT) in a group of patients with various grades of DD based on echocardiography.

METHODS

We identified 35 patients with DD by echocardiography, who had also undergone cardiac CT, and 35 age-matched normal controls. LV and LA volumes were measured every 10% of the RR interval, using semi-automatic software. From these, - systolic, early-diastolic and late-diastolic volume changes were calculated, and additional parameters of diastolic filling derived. Conduit volume was defined as the difference between the LV and LA early-diastolic volume change.

RESULTS

Patients with DD had significantly larger LV mass, and LA volumes, reduced early emptying volumes and increased conduit volume as percent of early LV filling (All p<0.001). LA function, manifesting as total emptying fraction (LATEF), decreased proportionately with worsening grades of DD (p<0.001). LA contractile function was maintained until advanced grade-3 DD. By receiver operating characteristic analysis, LATEF had an AUC of 0.88 to separate between normals and DD. At a threshold of <42.5%, LATEF has 97% sensitivity and 69% specificity to detect DD.

CONCLUSIONS

DD is characterized by reduced LA function and an alteration in the relative contributions of the atrial emptying and conduit volume components of early LV filling. In patients undergoing cardiac CT, it is possible to identify the presence and severity of DD.

Left atrial passive emptying function is preserved in patients with permanent atrial fibrillation--a 320-slice multidetector computed tomography study

OBJECTIVE

Left atrial (LA) mechanical function is thought to be virtually inexistent in patients with permanent atrial fibrillation (AF). Due to recent advances in multidetector computed tomography (MDCT) technology, it is now possible to acquire images of the entire heart in a single heartbeat. The objective of this study was to compare individual components of LA function assessed by MDCT in patients with permanent AF and patients in sinus rhythm (SR).

METHODS

320-slice MDCT was performed in 30 patients with permanent AF. Measurements of LA volumes during the cardiac cycle were compared to 30 patients in SR, who were matched with respect to age, sex, left ventricular ejection fraction and body surface area.

RESULTS

LA volumes were significantly larger in patients with AF than SR patients at all times during the cardiac cycle (LA maximal volume; 82 vs. 55 ml/m(2), p < 0.0001, LA minimal volume; 71 vs. 30 ml/m(2), p < 0.0001). However, except for the absence of active LA emptying, the overall trend of the LA time-volume curve was similar in patients with AF and SR.

CONCLUSION

Compared to SR patients, patients with permanent AF have significantly increased LA volumes throughout the cardiac cycle. Yet, a residual hemodynamic role of LA function may be maintained during permanent AF.

Left atrial remodeling in hypertrophic cardiomyopathy and susceptibility markers for atrial fibrillation identified by cardiovascular magnetic resonance

In hypertrophic cardiomyopathy (HC), atrial fibrillation (AF) is an important determinant of clinical deterioration due to heart failure or embolic stroke. This study characterizes left atrial (LA) structural and functional parameters to establish markers predictive of AF risk, using cardiovascular magnetic resonance (CMR) imaging. We studied 427 consecutive patients with HC in sinus rhythm with CMR (age 44±18 years), including 41 who developed clinically overt AF after study entry (2.6±2.1 years), 49 patients with AF before CMR, 337 patients with HC but without AF, and 244 normal controls. LA chamber was assessed for absolute and indexed end-diastolic volume (LAEDV), end-systolic volume, and percent ejection fraction (LAEF). In the 41 prospectively studied patients with HC who developed AF during follow-up, LAEDV was significantly greater than in patients without AF (146±48 vs 107±37 ml) or in normal controls (81±24 ml, p<0.001). Percent LAEF was lower in patients developing AF (36±10%) than without AF (46±12%) or controls (55±9%, p<0.001). Multivariate analysis identified LAEF (<38%), LAEDV (≥118 ml), and age (≥40 years) as independently associated with AF occurrence. In conclusion, CMR measures of LA remodeling and dysfunction reliably identified patients with HC at risk for future development of AF. Decrease in LAEF represents a strong novel marker of susceptibility to AF in this disease.

Aging reduces left atrial performance during adrenergic stress in middle aged and older patients

BACKGROUND

During adrenergic stress, the influence of age on left atrial (LA) function is unknown. We hypothesized that aging decreases LA total emptying fraction (LAEF) during maximal adrenergic stress. The aim of the study was to determine the influence of aging on LA function during adrenergic stress in middle aged and older patients.

METHODS

We enrolled 167 middle aged and elderly participants, and measured LA and left ventricular (LV) volumes using a multi-slice three-dimensional cine white blood cardiovascular magnetic resonance (CMR) technique before and during intravenous dobutamine infused to achieve 80% of the maximum heart rate response for age. Paired sample t-test was used to detect differences in LA and LV volumes between baseline and peak dose stage of dobutamine stress CMR, and multivariable linear regression was used to identify predictors of LA function.

RESULTS

Participants averaged 68 ± 8 years in age, 53% were men, 25% exhibited coronary artery disease, 35% had diabetes, 9% had a remote history of atrial fibrillation, 90% had hypertension, and 11% had inducible LV wall motion abnormalities indicative of ischemia during dobutamine CMR. Increasing age correlated with LA volumes (maximal and minimal) and inversely correlated with LAEF at rest and after peak adrenergic stress. Age was an independent predictor of LAEF during adrenergic stress, even after accounting for gender, LV volumes, and other co-morbidities including inducible ischemia.

CONCLUSIONS

Age is associated with a decrease in LA function during adrenergic stress even after adjusting for co-morbidities associated with cardiovascular disease and LV function.

Evaluation of left atrial function in patients with coronary artery disease by two-dimensional strain and strain rate imaging

BACKGROUND

Left ventricular (LV) dysfunction in patients with coronary artery disease is shown by strain and strain rate imaging. However, left atrium (LA) function in patients with coronary artery disease (CAD) has not been assessed by this method.

METHODS AND RESULTS

In 34 CAD patients, including 17 patients with enlarged LA (LA diameter ≤ 4.0 cm) and 17 with normal-size LA (LA diameter ≤ 4.0 cm), two-dimensional strain echocardiographic imaging (2DSE) was performed. Twenty healthy subjects as a control group were included. Both conventional parameters and strain parameters, such as LA peak systolic strain (LAs S/SR), preatrial contraction strain (LAa S), peak systolic (LAs SR), early diastolic strain rate (LAe SR) and late diastolic strain rate (LAa SR), were measured. Conventional parameters were abnormal in CAD patients with enlarged LA (ELA), but there were no significant differences between CAD with normal-size left atrium (NLA) and control groups. LAs S/SR and LAe SR were lower in patients than in normal controls, and were even lower in CAD-ELA group (P < 0.05). LAa S/SR were lower in CAD patients with ELA (P < 0.05), but without a significant difference between CAD-NLA and control groups. A significant correlation was observed between LAs S/SR and LA emptying fraction (r = 0.85, P < 0.05; r = 0.72, P < 0.05, respectively). LAa S/SR related well to LA ejection fraction (r = 0.68, P < 0.05; r = 0.61, P < 0.05, respectively). LAs SR was most accurate in identifying both CAD patients with NLA from controls and CAD patients from controls (area under the curve: 0.91; 0.95, respectively).

CONCLUSIONS

LA diastolic dysfunction occurs prior to LA systolic dysfunction in CAD patients, and LAs SR is the most accurate index in identifying patients with CAD.