Dataset Information

Both beat-to-beat changes in RR-interval and left ventricular filling time determine ventricular function during atrial fibrillation.

ABSTRACT:

Aims

The irregular atrial electrical activity during atrial fibrillation (AF) is associated with a variable left ventricular (LV) systolic function. The mechanisms determining LV function during AF remain incompletely understood. We aimed at elucidating how changes in RR-interval and LV preload affect LV function during AF.

Methods and results

Beat-to-beat speckle-tracking echocardiography was performed in 10 persistent AF patients. We evaluated the relation between longitudinal LV peak strain and preceding RR-interval during AF. We used the CircAdapt computational model to evaluate beat-to-beat preload and peak strain during AF for each patient by imposing the patient-specific RR-interval sequences and a non-contractile atrial myocardium. Generic simulations with artificial RR-interval sequences quantified the haemodynamic changes induced by sudden irregular beats. Clinical data and simulations both showed a larger sensitivity of peak strain to changes in preceding RR-interval at slow heart rate (HR) (cycle length, CL <750 ms) than at faster HR. Simulations explained this by a difference in preload of the current beat. Generic simulations confirmed a larger sensitivity of peak strain to preceding RR-interval at fast HR (CL = 600 ms: Δ peak strain = 3.7% vs. 900 ms: Δ peak strain = 0.3%) as in the patients. They suggested that longer LV activation with respect to preceding RR-interval is determinant for this sensitivity.

Conclusions

During AF, longitudinal LV peak strain is highly variable, particularly at fast HR. Beat-to-beat changes in preload explain the differences in LV systolic function. Simulations revealed that a reduced diastolic LV filling time can explain the increased variability at fast HR.

SUBMITTER: Lyon A

PROVIDER: S-EPMC7943365 | biostudies-literature | 2021 Mar

REPOSITORIES: biostudies-literature

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Publications

Both beat-to-beat changes in RR-interval and left ventricular filling time determine ventricular function during atrial fibrillation.

Lyon Aurore A van Mourik Manouk M Cruts Laura L Heijman Jordi J Bekkers Sebastiaan C A M SCAM Schotten Ulrich U Crijns Harry J G M HJGM Linz Dominik D Lumens Joost J

Europace : European pacing, arrhythmias, and cardiac electrophysiology : journal of the working groups on cardiac pacing, arrhythmias, and cardiac cellular electrophysiology of the European Society of Cardiology 20210301 23 Suppl 1

<h4>Aims</h4>The irregular atrial electrical activity during atrial fibrillation (AF) is associated with a variable left ventricular (LV) systolic function. The mechanisms determining LV function during AF remain incompletely understood. We aimed at elucidating how changes in RR-interval and LV preload affect LV function during AF.<h4>Methods and results</h4>Beat-to-beat speckle-tracking echocardiography was performed in 10 persistent AF patients. We evaluated the relation between longitudinal L ...[more]

PMID: 33751072

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Project description:PurposeTo determine whether left ventricular (LV) extracellular volume (ECV) expansion is associated with atrial fibrillation (AF) or AF-mediated LV systolic dysfunction (LVSD) while minimizing the influence of biologic and imaging methodologic confounders.Materials and methodsThis study examined the prevalence of LV ECV expansion in 137 patients with AF (mean age, 62 years ± 11 [standard deviation]; 92 male patients and 45 female patients; 83 paroxysmal and 54 persistent) who underwent preablation cardiovascular MRI. Biologic confounders were minimized by measuring the ECV fraction and excluding patients with severe LV hypertrophy, defined as wall thickness greater than 1.5 cm. Imaging confounders were minimized by using an arrhythmia-insensitive-rapid (AIR) cardiac T1 mapping pulse sequence. Other cardiac functional parameters, including LV ejection fraction (LVEF) and left atrial end-diastolic volume indexed to body surface area, were assessed using cine cardiovascular MRI. A substudy was conducted in 32 patients with no AF (mean age, 54 years ± 16) in sinus rhythm to establish control values and convert these values between the AIR sequence and literature-based modified Look-Locker inversion recovery (MOLLI) values.ResultsThe mean ECV was not significantly different (P > .05) between patients with AF with a normal LVEF (24.5% ± 2.8; n = 107), patients with AF with LVSD (24.5% ± 2.5; n = 30), and patients with no AF (24.4% ± 3.8; n = 32), but there was a significant interaction between ECV and CHA2DS2-VASc score (P = .045). Compared with the literature data obtained from healthy control patients scanned using MOLLI, 99.3% of patients with AF had ECV below the fibrosis cutoff point (32.8% when converted from MOLLI T1 mapping to AIR T1 mapping), including a subset of patients with AF (n = 28) with low CHA2DS2-VASc score (0/1 for men/women).ConclusionStudy results suggest that an LV ECV expansion is not associated with AF or AF-mediated LVSD. Supplemental material is available for this article. © RSNA, 2020See also the commentary by Stillman in this issue.

Project description:BackgroundHemodynamic assessment of left atrial (LA) flow using phase contrast MRI provides insight into thromboembolic risk in atrial fibrillation (AF). However, conventional flow imaging techniques are averaged over many heartbeats.PurposeTo evaluate beat-to-beat variability and LA hemodynamics in patients with AF using real time phase contrast (RTPC) MRI.Study typeProspective.SubjectsThirty-five patients with history of AF (68 ± 10 years, nine female), 10 healthy controls (57 ± 19 years, four female).Field strength/sequence5T, 2D RTPC with through-plane velocity-encoded gradient echo sequence and 4D flow MRI with three-directional velocity-encoded gradient echo sequence.AssessmentRTPC was continuously acquired for a mid-LA slice in all subjects. 4D flow data were interpolated at the RTPC location and normally projected for comparison with RTPC. RR intervals extracted from RTPC were used to calculate heart rate variability (HRV = interquartile range over median × 100%). Patients were classified into low (<9.7%) and high (>9.7%) HRV groups. LA peak/mean velocity and stasis (%velocities < 5.8 cm/sec) were calculated from segmented 2D images. Variability in RTPC flow metrics was quantified by coefficient of variation (CV) over all cycles.Statistical testsPearson's correlation coefficient (r), Bland-Altman analysis, Kruskal-Wallis test. A P value < 0.05 was considered statistically significant.ResultsRTPC and 4D flow measurements were strongly/significantly correlated for all hemodynamic parameters (R2 = 0.75-0.83) in controls. Twenty-four patients had low HRV (mean = 4 ± 2%) and 11 patients had high HRV (27 ± 9%). In patients, increased HRV was significantly correlated with CV of peak velocity (r = 0.67), mean velocity (r = 0.51), and stasis (r = 0.41). A stepwise decrease in peak/mean velocity and increase in stasis was observed when comparing controls vs. low HRV vs. high HRV groups. Mean velocity and stasis differences were significant for control vs. high HRV groups.ConclusionsRTPC may be suitable for assessing the impact of HRV on hemodynamics and provide insight for AF management in highly arrhythmic patients.Evidence level1 TECHNICAL EFFICACY: Stage 2.

Project description:This study aimed to investigate the functional correlate, clinical relevance, and prognostic implications of novel left ventricular (LV) deformations in patients with atrial fibrillation (AF). LV deformational indices, including peak global longitudinal strain (GLS), systolic strain rates (SRs), and early diastolic strain rates (SRe) were measured in a large-scale AF population. We related such measures to key clinical heart failure (HF) markers, conventional echocardiographic ventricular parameters, and clinical outcomes. Among 1483 subjects with newly diagnosed AF (mean age, 71.6 ± 12.4 years; 55.5% male), worsened GLS (mean, - 12.6 ± 3.9%) and strain rates (SRs and SRe: mean, - 0.86 ± 0.27 and 1.25 ± 0.41 1/s, respectively) by our three-beat measures were independently correlated with higher C-reactive protein, N-terminal pro-B-type natriuretic peptide, higher E/e', more impaired LV ejection fraction (LVEF < 50%), lower estimated glomerular filtration rate, permanent AF, and prevalent HF (all P < 0.05). LV deformations by three-beat analysis well correlated with the respective results of traditional methods. Abnormal GLS (>- 14.7%) was common in our cohort (67.8%) despite an averaged preserved LVEF (58.4 ± 14.2%), with worse GLS and SRe being associated with higher composite HF re-admissions/death during the 2.9 year follow-up (inter-quartile range, 1.6-4.1 years) in multivariate models incorporating key LV indices (LVEF, LV mass index, and E/e') (all P < 0.001). Sensitivity analysis by excluding those with regional wall motion abnormality showed broadly similar findings. An improved risk reclassification was observed when GLS and SRe were separately added to the LVEF. Comparison of the AF cohort with a fully matched independent non-AF cohort at the same baseline LVEF level showed a substantially lower GLS [- 13.2 ± 3.8% (AF) vs. 18.1 ± 3.2% (non-AF)] and higher clinical events rate (hazard ratio, 1.41 [95% confidence interval, 1.14-1.75]; log-rank P = 0.002) in the AF cohort. Impaired LV function defined by myocardial deformation was common in patients with AF and provides independent prognostic values over conventional measures with improved risk prediction. Our data highlight the need for implementing cardiac deformations in daily practice for patients with AF.

Project description:Atrial fibrillation (AF)-induced peripheral microcirculatory alterations have poorly been investigated. The present study aims to expand current knowledge through a beat-to-beat analysis of non-invasive finger photoplethysmography (PPG) in AF patients restoring sinus rhythm by electrical cardioversion (ECV). Continuous non-invasive arterial blood pressure and left middle finger PPG pulse oximetry waveform (POW) signals were continuously recorded before and after elective ECV of consecutive AF or atrial flutter (AFL) patients. The main metrics (mean, standard deviation, coefficient of variation), as well as a beat-to-beat analysis of the pulse pressure (PP) and POW beat-averaged value (aPOW), were computed to compare pre- and post-ECV phases. 53 patients (mean age 69 ± 8 years, 79% males) were enrolled; cardioversion was successful in restoring SR in 51 (96%) and signal post-processing was feasible in 46 (87%) patients. In front of a non-significant difference in mean PP (pre-ECV: 51.96 ± 13.25, post-ECV: 49.58 ± 10.41 mmHg; p = 0.45), mean aPOW significantly increased after SR restoration (pre-ECV: 0.39 ± 0.09, post-ECV: 0.44 ± 0.06 a.u.; p < 0.001). Moreover, at beat-to-beat analysis linear regression yielded significantly different slope (m) for the PP (RR) relationship compared to aPOW(RR) [PP(RR): 0.43 ± 0.18; aPOW(RR): 1.06 ± 0.17; p < 0.001]. Long (> 95th percentile) and short (< 5th percentile) RR intervals were significantly more irregular in the pre-ECV phases for both PP and aPOW; however, aPOW signal suffered more fluctuations compared to PP (p < 0.001 in both phases). Present findings suggest that AF-related hemodynamic alterations are more manifest at the peripheral (aPOW) rather than at the upstream macrocirculatory level (PP). Restoring sinus rhythm increases mean peripheral microvascular perfusion and decreases variability of the microvascular hemodynamic signals. Future dedicated studies are required to determine if AF-induced peripheral microvascular alterations might relate to long-term prognostic effects.

Project description:BackgroundDiastolic dysfunction is associated with morbidity and mortality in multiple pediatric disease processes. Cardiovascular magnetic resonance (CMR) provides a non-invasive method of studying left ventricular (LV) diastolic dysfunction through the assessment of LV filling curves and left atrial (LA) volume and function. However, there are no normative data for LV filling curves and the standard method is time-intensive. This study aims to compare an alternate, more rapid method of obtaining LV filling curves to standard methodology and report normative CMR diastolic function data for LV filling curves and LA volumes and function.MethodsNinety-six healthy pediatric subjects (14.3 ± 3.4 years) with normal CMR defined by normal biventricular size and systolic function without late gadolinium enhancement were included. LV filling curves were generated by removing basal slices without myocardium present throughout the cardiac cycle and apical slices with poor endocardial delineation (compressed method), then re-generated including every phase of myocardium from apex to base (standard method). Indices of diastolic function included peak filling rate and time to peak filling. Systolic metrics included peak ejection rate and time to peak ejection. Both peak ejection and peak filling rates were indexed to end-diastolic volume. LA maximum, minimum and pre-contraction volumes were calculated using a biplane method. Inter-and intra-observer variability were assessed with intraclass correlation coefficient. Multivariable linear regression was used to assess the effects of body surface area (BSA), gender and age on metrics of diastolic function.ResultsBSA had the largest effect on LV filling curves. Normal LV filling data are reported for both compressed and standard methods. The time to perform the compressed method was significantly shorter than the standard method (median 6.1 min vs. 12.5 min, p < 0.001). Both methods had strong to moderate correlation for all metrics. Intra-observer reproducibility was moderate to high for all LV filling and LA metrics except for time to peak ejection and peak filling.ConclusionsWe report reference values for LV filling metrics and LA volumes. The compressed method is more rapid and produces similar results to standard methodology, which may facilitate the use of LV filling in clinical CMR reporting.

Dataset Information

Both beat-to-beat changes in RR-interval and left ventricular filling time determine ventricular function during atrial fibrillation.

Aims

Methods and results

Conclusions

Publications

Both beat-to-beat changes in RR-interval and left ventricular filling time determine ventricular function during atrial fibrillation.

Similar Datasets

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