Cardiovascular magnetic resonance imaging for accurate sizing of the left atrium: predictability of pulmonary vein isolation success in patients with atrial fibrillation

Comparison of Biplane Area-Length Method and 3D Volume Quantification by Using Cardiac MRI for Assessment of Left Atrial Volume in Atrial Fibrillation

Purpose

To compare maximum left atrial (LA) volume (LAV) from the routinely used biplane area-length (BAL) method with three-dimensional (3D)-based volumetry from late gadolinium-enhanced MRI (3D LGE MRI) and contrast-enhanced MR angiography (3D CE-MRA) in patients with atrial fibrillation (AF).

Materials and Methods

Sixty-four patients with AF (mean age, 63 years ± 9 [SD]; 40 male patients) were retrospectively included from a prospective cohort acquired between October 2018 and February 2021. All patients underwent a research MRI examination that included standard two- and four-chamber cine acquisitions, 3D CE-MRA, and 3D LGE MRI performed prior to the atrial kick. Contour delineation on cine imaging and LA 3D segmentations were performed by a radiologist. Maximum LAV (BALmax) was extracted from the BAL volume-time curve and compared with LAV from 3D CE-MRA and 3D LGE MRI. The Kruskal-Wallis test was performed, followed by the Dunn post hoc test and Bland-Altman analyses. Interobserver variability was assessed in 10 patients.

Results

BALmax underestimated LAV compared with 3D CE-MRA (bias: -23.5 mL ± 46.2, P < .001) and 3D LGE MRI (bias: -31.3 mL ± 58.3, P < .001), whereas 3D LGE MRI volumes showed no evidence of a difference from 3D CE-MRA (bias: 7.8 mL ± 45.7, P = .38). Interobserver variability yielded excellent agreement for each method (intraclass correlation coefficient, 0.96-0.98).

Conclusion

BALmax underestimated LAV in patients with AF compared with 3D LGE MRI and 3D CE-MRA, suggesting that the geometric assumption of an ellipsoidal LA shape in BAL does not reflect LA geometry in patients with AF.Keywords: Left Atrial Volume, Biplane Area-Length, Late Gadolinium-enhanced 3D MRI, Contrast-enhanced 3D MR Angiography, Atrial Fibrillation Supplemental material is available for this article. © RSNA, 2023.

Patients' attitude towards a sham-controlled trial on pulmonary vein isolation in atrial fibrillation

Background

The interpretation of recent trials on pulmonary vein ablation (PVI) for the treatment of atrial fibrillation (AF) is hampered by the lack of blinding and sham controls. The feasibility of a sham-controlled trial has been questioned. We aimed to assess the attitude of potential participants regarding a sham-controlled trial in a common AF-patient population planned for PVI.

Methods

Patients in two tertiary care centres planned for PVI were asked for their current AF symptoms using the Atrial Fibrillation Effect on QualiTy of Life (AFEQT) questionnaire 1 day before catheter ablation. Subsequently, the study design of a hypothetical sham-controlled PVI-study was introduced, and patients were asked for their agreement in participation. Telephone follow-up of the AFEQT questionnaire was conducted 3 months after PVI.

Results

One hundred and ninety-six patients (mean age 64 ± 11 years, 63% male) were included. Seventy-nine (40%) patients expressed their agreement to participate in the hypothetical sham-controlled trial. An additional 7% agreed to participate if a cross-over option after three months was offered. Agreement rate was similar in patients with first and Redo-PVI and minimal, moderate or severe symptoms. Mean overall AFEQT at baseline was 55 ± 19 and improved by 25 ± 20 points after 3 months (p < 0.001 versus baseline).

Conclusion

With a participation rate of 40% in potential study participants, a sham-controlled trial for pulmonary vein isolation seems feasible. Patient-reported symptom relief after pulmonary vein isolation is in accordance with previous randomized open studies. The benefit of PVI should be rigorously evaluated in a sham-controlled trial.

Graphic abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s00392-021-01959-z.

Association Between Cardiovascular Magnetic Resonance-Derived Left Atrial Dimensions, Electroanatomical Substrate and NT-proANP Levels in Atrial Fibrillation

Background Enlargement of left atrial ( LA ) size indicates advanced disease stage in patients with atrial fibrillation ( AF ) and is associated with poor success of different AF therapies. Two dimensional echocardiographic LA measurements do not reliably reflect the true size of LA anatomy. The aim of the current study was: 1) to analyze cardiovascular magnetic resonance ( CMR )-derived LA dimensions and their association with low voltage areas ( LVA ); and 2) to investigate the association between these parameters and NT -pro ANP (N-terminal proatrial natriuretic peptide) levels. Methods and Results Patients undergoing first AF catheter ablation were included. All patients underwent CMR imaging (Ingenia 1.5T Philips) before intervention. CMR data ( LA volume, superior-inferior, transversal and anterior-posterior LA diameters) were measured in all patients. LVA were determined using high-density maps and a low voltage threshold <0.5 mV. Blood plasma samples from femoral vein were collected before catheter ablation. NT -pro ANP levels were studied using commercially available assays. There were 216 patients (65±11 years, 59% males, 56% persistent AF , 26% LVA ) included into analyses. NT -pro ANP levels in patients with LVA were significantly higher than in those without (median/interquartile range 22 [13-29] versus 15 [9-22] pg/mL, P=0.004). All CMR derived LA diameters correlated significantly with persistent AF ( r²=0.291-0.468, all P<0.001), LVA ( r²=0.187-0.306, all P<0.001), and NT -pro ANP levels ( r²=0.258-0.352, P<0.01). On logistic regression multivariable analysis, age (odds ratio=1.090, 95% confidence interval: 1.030-1.153, P=0.003), females (odds ratio=2.686, 95% confidence interval: 1.047-6.891, P=0.040), and LA volume (odds ratio=1.022, 95% confidence interval: 1.009-1.035, P=0.001) remained significant predictors for LVA . Conclusions Left atrial CMR parameters are associated with persistent AF , low voltage areas and NT -pro ANP levels. LA volume is the most significant predictor for LVA .

Comparison of non-triggered magnetic resonance imaging and echocardiography for the assessment of left atrial volume and morphology

BACKGROUND

Advanced atrial fibrillation (AF) patients have persistent AF, failed previous catheter ablation and/or an enlarged left atrium (LA), which is associated with a reduced success of AF ablation. Transthoracic echocardiography (TTE) and contrast enhanced magnetic resonance angiography (CE-MRA) are available to assess LA volume. However, it is unknown how these modalities relate in patients with advanced AF. We therefore compared the reproducibility of TTE and non-triggered CE-MRA in advanced AF patients and their ability to select patients with successful thoracoscopic AF ablation.

METHODS

Two independent observers measured LA volumes on 65 TTE and CE-MRA exams of advanced AF patients prior to AF ablation. Patients were followed after AF ablation with rhythm monitoring every 3 months for 1 year to determine AF recurrence. Inter-modality, inter- and intra-observer variability were determined using intraclass correlation coefficients (ICC). Receiver-operating characteristic (ROC) analysis was performed to determine sensitivity and specificity of TTE and CE-MRA volume and CE-MRA dimensions to identify patients with AF recurrence during follow-up.

RESULTS

LA enlargement ≥ 34 ml/m2 was present in 60% of the patients. CE-MRA and TTE demonstrated a good correlation for LA volume assessment (intraclass correlation, ICC = 0.86; p < 0.001) with larger volumes consistently measured by CE-MRA. Major discrepancies were mostly attributed to TTE acquisition. Craniocaudal enlargement discriminated patients with AF recurrence (AUC 0.67 [95% CI 0.55-0.85], p = 0.01).

CONCLUSIONS

Non-triggered CE-MRA is a viable and reproducible 3D alternative for 2D TTE to assess LA volume in advanced AF patients. Craniocaudal enlargement was the only discriminator of AF recurrence after AF ablation.

Quantification of the left atrium applying cardiovascular magnetic resonance in clinical routine

OBJECTIVES

In recent years the impact of the left atrium (LA) has become more evident in different cardiovascular pathologies. We aim to provide LA parameters in healthy volunteers for cardiovascular magnetic resonance (CMR) using a fast approach.

DESIGN

We analyzed 203 healthy volunteers (mean age 44.6 years (y), range 19y-76y) at 1.5 and 3.0 Tesla (T) using steady-state free precession (SSFP) cine in routine long axis view. Left atrial enddiastolic volume (LA-EDV), endsystolic volume (LA-ESV), stroke volume (LA-SV) and ejection fraction (LA-EF) were quantified and indexed to body-surface-area (BSA). Dependency on age and sex was analyzed.

RESULTS

21 subjects had to be excluded. In the remaining, there was no significant difference between 1.5 T and 3.0 T. Absolut LA-EDV and LA-ESV were larger in men than in women (LA-EDV: male 70 ± 19 ml vs. female 61 ± 16 ml (p = .001); LA-ESV: male 24 ± 9 ml vs. female 21 ± 8 ml (p = .01)). These differences disappeared after indexing to BSA (LA-EDV/BSA: male 34 ± 10 ml/m² vs. female 33 ± 9 ml/m² (p = .65) and LA-ESV/BSA: male 12 ± 4 ml/m² vs. female 11 ± 4 ml/m² (p = .71)). LA-EDV/BSA decreased with older age.

CONCLUSIONS

Reference values for LA size and function based on a fast approach are provided. LA size decreases with older age. Normalization to body size overcomes sex-dependency. Reports should be related to body size.

Quantification of left atrial volume and phasic function using cardiovascular magnetic resonance imaging-comparison of biplane area-length method and Simpson's method

Left atrial (LA) enlargement and dysfunction are markers of chronic diastolic dysfunction and an important predictor of adverse cardiovascular and cerebrovascular outcomes. Accordingly, accurate quantification of left atrial volume (LAV) and function is needed. In routine clinical cardiovascular magnetic resonance (CMR) imaging the biplane area-length method (Bi-ALM) is frequently applied due to time-saving image acquisition and analysis. However, given the varying anatomy of the LA we hypothesized that the diagnostic accuracy of the Bi-ALM is not sufficient and that results would be different from a precise volumetric assessment of transversal multi-slice cine images using Simpson's method. Thirty one patients of the FIND-AF_RANDOMISED-study with status post acute cerebral ischemia (mean age 70.5 ± 6.2 years) received CMR imaging at 3T. The study protocol included cine SSFP sequences in standard 2- and 4 CV and a stack of contiguous slices in transversal orientation. Total, passive and active LA emptying fractions were calculated from LA maximal volume, minimal volume and volume prior to atrial contraction. Intra- and inter-observer variability was assessed in ten patients. Significant differences were found for LA volume and phasic function. The Bi-ALM significantly underestimated LA volume and overestimated LA function in comparison to Simpson's method (Bi-ALM vs. Simpson's method: LAV_max: 80.18 vs. 98.80 ml; LAV_pre-ac: 61.09 vs. 80.41 ml; LAV_min: 36.85 vs. 52.66 ml; LAEF_Total: 55.17 vs. 47.85%; LAEF_Passive: 23.96 vs. 19.15%; LAEF_Booster: 40.87 vs. 35.64%). LA volumetric and functional parameters were reproducible on an intra- and inter-observer levels for both methods. Intra-observer agreement for LA function was better for Simpson's method (Bi-ALM vs. Simpson's method; ICC LAEF_Total: 0.84 vs. 0.96; ICC LAEF_Passive: 0.74 vs. 0.92; ICC LAEF_Booster: 0.86 vs. 0.89). The Bi-ALM is based on geometric assumptions that do not reflect the complex individual LA geometry. The assessment of transversal slices covering the left atrium with Simpson's method is feasible and might be more suitable for an accurate quantification of LA volume and phasic function.

Automated quantification of left atrial size using three-beat averaging real-time three dimensional Echocardiography in patients with atrial fibrillation

Background

Left atrial (LA) sizing in patients with atrial fibrillation (AF) is crucial for follow-up and outcome. Recently, the automated quantification of LA using the novel three-beat averaging real-time three dimensional echocardiography (3BA-RT3DE) is introduced. The aim of this study was to assess the feasibility and accuracy of 3BA-RT3DE in patients with atrial fibrillation (AF).

Methods

Thirty-one patients with AF (62.8 ± 11.7 years, 67.7 % male) were prospectively recruited to have two dimensional echocardiography (2DE) and 3BA-RT3DE (SC 2000, ACUSON, USA). The maximal left atrial (LA) volume was measured by the conventional prolate-ellipse (PE) and area-length (AL) method using three-beat averaging 2D transthoracic echocardiography and automated software analysis (eSie volume analysis, Siemens Medical Solution, Mountain view, USA); measurements were compared with those obtained by computed tomography (CT).

Results

Maximal LA volume by 3BA-RT3DE was feasible for all patients. LA volume was 68.4 ± 28.2 by PE-2DE, 89.2 ± 33.1 by AL-2DE, 100.6 ± 31.8 by 3BA-RT3DE, and 131.2 ± 42.2 mL by CT. LA volume from PE-2DE (R² = 0.48, p < 0.001, ICC = 0.64, p < 0.001), AL-2DE (R² = 0.47, p < 0.001, ICC = 0.67, p < 0.001), and 3BA-RT3DE (R² = 0.50, p = 0.001, ICC = 0.65, p < 0.001) showed significant correlations with CT. However, 3BA-RT3DE demonstrated a small degree of underestimation (30.5 mL) of LA volume compared to 2DE-based measurements. Good-quality images from 3BA-RT3DE (n = 16) showed a significantly tighter correlation with images from CT scanning (R² = 0.60, p = 0.0004, ICC = 0.76, p < 0.001) compared to those of fair quality.

Conclusion

Automated quantification of LA volume using 3BA-RT3DE is feasible and accurate in patients with AF. An image of good quality is essential for maximizing the value of this method in clinical practice.

Right Atrial Volume is Increased in Corrected Tetralogy of Fallot and Correlates with the Incidence of Supraventricular Arrhythmia: A CMR Study

The aim of this study was to evaluate right atrial (RA) volume in corrected Tetralogy of Fallot (cTOF) and assess its correlation with the occurrence of supraventricular (SV) arrhythmia. Cardiac magnetic resonance imaging (CMR) and 24-h Holter were performed in n = 67 consecutive cTOF patients (age 30 ± 11.3 years). The CMR protocol included standard HASTE, SSFP cine, and blood flow measurements. Correlations between arrhythmia in ECG, heart volume, and functional parameters were investigated by negative binominal regression. Patients' characteristics (mean ± SD) included mean RA volume of 49 ± 19 ml/m(2) (HASTE sequence), mean right ventricular (RV) end-diastolic volume of 98 ± 27 ml/m(2), mean pulmonary valve regurgitation fraction (PR) of 21 ± 19 %, BMI of 25 kg/m(2), and heart rate of 75/min. Twenty-eight out of 67 patients experienced SV arrhythmia including SV couplets or bigeminus or longer non-sustained SV tachycardia (SVT) episodes. RA volume index was identified as an independent risk factor for different degrees of SV arrhythmia (SV couplets/bigeminus p < 0.001, SVT p < 0.001). Further risk factors for SV arrhythmia were male gender (p = 0.023) and decreased left ventricular (LV) ejection fraction (EF) (LV EF p < 0.001). RA volume is increased in adult patients with cTOF with larger RA volumes relating to higher incidence of SV arrhythmia. SV arrhythmia also appeared more often in male patients and those with decreased LV EF. Risk stratification according to these parameters could help to optimize early prevention and adjusted individual therapy to improve patient outcome and quality of life.

The Role of Magnetic Resonance Imaging and Cardiac Computed Tomography in the Assessment of Left Atrial Anatomy, Size, and Function

In the last decade, there has been increasing evidence that comprehensive evaluation of the left atrium is of utmost importance. Numerous studies have clearly demonstrated the prognostic value of left atrial volume for long-term outcome. Furthermore, advances in catheter ablation procedures used for the treatment of drug-refractory atrial fibrillation require the need for detailed knowledge of left atrial and pulmonary venous morphology as well of atrial wall characteristics. This review article discusses the role of cardiac magnetic resonance and computed tomography in assessment of left atrial size, its normal and abnormal morphology, and function. Special interest is paid to the utility of these rapidly involving noninvasive imaging methods before and after atrial fibrillation ablation.

Single breath-hold 3D measurement of left atrial volume using compressed sensing cardiovascular magnetic resonance and a non-model-based reconstruction approach

BACKGROUND

Left atrial (LA) dilatation is associated with a large variety of cardiac diseases. Current cardiovascular magnetic resonance (CMR) strategies to measure LA volumes are based on multi-breath-hold multi-slice acquisitions, which are time-consuming and susceptible to misregistration.

AIM

To develop a time-efficient single breath-hold 3D CMR acquisition and reconstruction method to precisely measure LA volumes and function.

METHODS

A highly accelerated compressed-sensing multi-slice cine sequence (CS-cineCMR) was combined with a non-model-based 3D reconstruction method to measure LA volumes with high temporal and spatial resolution during a single breath-hold. This approach was validated in LA phantoms of different shapes and applied in 3 patients. In addition, the influence of slice orientations on accuracy was evaluated in the LA phantoms for the new approach in comparison with a conventional model-based biplane area-length reconstruction. As a reference in patients, a self-navigated high-resolution whole-heart 3D dataset (3D-HR-CMR) was acquired during mid-diastole to yield accurate LA volumes.

RESULTS

Phantom studies. LA volumes were accurately measured by CS-cineCMR with a mean difference of -4.73 ± 1.75 ml (-8.67 ± 3.54%, r2 = 0.94). For the new method the calculated volumes were not significantly different when different orientations of the CS-cineCMR slices were applied to cover the LA phantoms. Long-axis "aligned" vs "not aligned" with the phantom long-axis yielded similar differences vs the reference volume (-4.87 ± 1.73 ml vs. -4.45 ± 1.97 ml, p = 0.67) and short-axis "perpendicular" vs. "not-perpendicular" with the LA long-axis (-4.72 ± 1.66 ml vs. -4.75 ± 2.13 ml; p = 0.98). The conventional bi-plane area-length method was susceptible for slice orientations (p = 0.0085 for the interaction of "slice orientation" and "reconstruction technique", 2-way ANOVA for repeated measures). To use the 3D-HR-CMR as the reference for LA volumes in patients, it was validated in the LA phantoms (mean difference: -1.37 ± 1.35 ml, -2.38 ± 2.44%, r2 = 0.97). Patient study: The CS-cineCMR LA volumes of the mid-diastolic frame matched closely with the reference LA volume (measured by 3D-HR-CMR) with a difference of -2.66 ± 6.5 ml (3.0% underestimation; true LA volumes: 63 ml, 62 ml, and 395 ml). Finally, a high intra- and inter-observer agreement for maximal and minimal LA volume measurement is also shown.

CONCLUSIONS

The proposed method combines a highly accelerated single-breathhold compressed-sensing multi-slice CMR technique with a non-model-based 3D reconstruction to accurately and reproducibly measure LA volumes and function.

Role of cardiac computed tomography and cardiovascular magnetic resonance imaging in guiding management and treatment of patients with atrial fibrillation: state of the art review

Atrial fibrillation (AF) is the most common arrhythmia in clinical practice and is associated with high morbidity and mortality. In view of an aging population, the prevalence and incidence of AF are on the rise and are expected to double in the coming decades, posing a huge economic burden on already strained resources. New innovative therapies such as pulmonary vein isolation and percutaneous closure of the left atrial appendage have emerged. The current applications of such therapies would not have been possible without the pivotal role of multimodality cardiovascular imaging. The role of echocardiography in guiding therapy has been extensively reviewed. However, there are new data in support of other complementary imaging modalities, mainly cardiac computed tomography and cardiovascular magnetic resonance imaging, which will be the focus of this review.

Cardiovascular magnetic resonance: applications in daily practice

Over the last 10 years, the development of newer pulse sequences and applications in new clinical areas has enabled cardiovascular magnetic resonance to emerge as a powerful tool for the physicians to both diagnose and guide treatments of various cardiac pathologies. The greatest strengths of cardiovascular magnetic resonance include the assessment of ischemia and viability, evaluation of nonischemic cardiomyopathies, including myocarditis, pericardial disease, congenital heart disease, and tissue characterization of cardiac masses.