Atrial Electromechanical Sequence and Contraction Synchrony during Single- and Multisite Atrial Pacing in Patients with Brady-Tachycardia Syndrome

Atrial Dyssynchrony: A New Predictor for Atrial High-Rate Episodes in Patients with Cardiac Resynchronization Therapy

Background: Heart failure may induce atrial dyssynchrony. We aim to investigate whether preimplantation left atrial (LA) dyssynchrony could predict newly detected atrial high-rate episodes (AHRE) after receiving cardiac resynchronization therapy defibrillator (CRT-D). Methods: We conducted a retrospective analysis of consecutive patients who received CRT-D for standard indications and without a history of atrial fibrillation. The standard deviation of the time-to-peak strain in each LA segment during ventricular systole (SDs) and late diastole (SDa) were calculated to quantify LA dyssynchrony using two-dimensional speckle tracking echocardiography before device implantation. Patients were divided into the AHRE group and the AHRE-free group, depending on the presence of AHRE during device interrogation. Results: Thirty-one patients (28%) had newly detected AHRE during a mean follow-up of 21 ± 9 months. Patients in the AHRE group had higher SDs (8.2 ± 2.6% vs. 6.3 ± 2.3%, p < 0.001) and SDa (5.4 ± 1.8% vs. 4.1 ± 1.4%, p < 0.001) values before implantation than patients in the AHRE-free group. In the multivariate logistic analysis, both SDs (OR 1.325, 95% CI: 1.074–1.636, p =0.009) and SDa (OR: 1.499, 95% CI: 1.071–2.098, p= 0.018) were independent predictors of newly detected AHRE. At a cutoff value of 7.4% for SDs and 5.3% for SDa, the Kaplan-Meier survival analysis showed that patients with higher SDs and SDa had significantly increased risks of newly detected AHRE after receiving CRT-D. Conclusions: Dyssynchronous LA lengthening and contraction could assist in the prediction of newly detected AHRE in patients with CRT-D.

[Bachmann bundle pacing]

In pacemaker and ICD therapy, atrial leads are usually implanted in the right atrial appendage (RAA). This is easy but associated with a risk of negative hemodynamic and electrophysiological effects. Atrial depolarization, atrial contraction, and atrioventricular conduction can be delayed and desynchronized by RAA pacing leading to atrial fibrillation, pacing-induced long first-degree AV block, right ventricular pacing and the development of heart failure. High-septal atrial pacing near Bachmann's bundle that connects the right and left atrium can prevent the negative effects of RAA pacing and synchronize atrial excitation as demonstrated by the shortening of the PQ time and P wave duration during Bachmann bundle pacing. This review presents techniques to implant atrial leads at Bachmann's bundle. Apart from fluoroscopy in left anterior oblique projection, no additional effort compared to RAA implantation is required. Clinical studies on Bachmann bundle pacing are sparse; our own results suggest beneficial effects in patients with sick sinus syndrome and paroxysmal atrial fibrillation who receive atrial pacing for ≥50% of the time. Bachmann bundle pacing represents an interesting and simple option for atrial pacing. It is desirable to make this technique known to a wider spectrum of implanters and to generate more data on its clinical potential.

Left atrial appendage function assessment and thrombus identification

Background

The diagnosis of thrombus in the left atrium in patients with persistent atrial fibrillation (AF) and may be inconsistent because of variability in thrombus morphology. In some cases it is challenging and requires unusual approach. New Doppler-derived methods might be helpful to identify such thrombi. We evaluated quantitative differences in mechanical function of the left atrial appendage (LAA) basal segments using tissue Doppler imaging (TDI)and speckle tracking echocardiography (STE) in patients with non-valvular AF with and without LAA thrombus and compared them with SR patients.

Methods

A total of 80 patients with normal left ventricular ejection fraction underwent transesophageal echocardiography (40 patients with SR and 40 patients with AF on oral anticoagulants including patients with LAA thrombus). We analyzed the basal segments of LAA including left lateral ridge (LLR) and baso-medial appendage segment (BMAS). Quantitative analysis was used to calculate peak velocity, average velocity, strain, strain rate and deformation.

Results

In patients with AF the lower LLR strain rate was the sole new STE significant parameter differentiating patients with and without LAA thrombi: − 0.9(− 1.2; − 0.1)s^− 1 vs. − 1.6(− 1.9; − 1.3)s^− 1, (p = 0.004). Additionally, patients in SR demonstrated significantly better peak velocity, average velocity, strain, strain rate and deformation than those with AF (p < 0.001).

Conclusions

LLR appeared to be an appropriate site for measuring Doppler derived parameters. It is possible that the strain rate in LLR area may be a novel parameter correlating with the presence of thrombus in patients with AF.

Assessment of Atrial Electromechanical Delay and Left Atrial Mechanical Functions in Patients with Ulcerative Colitis

OBJECTIVE

Ulcerative colitis (UC) is a common inflammatory bowel disease causing systemic inflammation, which may also affect the cardiovascular system, as well as other organ systems. The aim of the current study was to evaluate left atrial (LA) mechanical functions and duration of atrial electromechanical delay (AEMD) with echocardiography in patients with UC.

METHOD

A total of 91 patients, 45 with UC (Group 1) and 46 healthy individuals as control (Group 2) were included in the study. The demographic and laboratory data were recorded, and echocardiographic measurements were taken for all patients.

RESULTS

In the evaluation of basal clinical and laboratory findings, no difference was detected between the two groups, except for white blood cell count (WBC) (8.26 ± 2.71 vs. 7.06 ± 1.70, P = 0.013) and high-sensitivity C-reactive protein (Hs-CRP; 3.4 ± 1.7 vs. 1.0 ± 0.8, P < 0.001). The echocardiographic assessment revealed that the diastolic parameters such as E-, E/A-, and E- waves decreased in the UC group when compared to the control group. LA mechanical functions were different between groups, except for left atrial (LA) maximal volume: LA minimum volume (22.2 ± 12.9 vs. 15.3 ± 4.7, P = 0.001), LA volume before atrial systole (29.9 ± 14.2 vs. 24.2 ± 4.9, P = 0.021), LA ejection fraction (27.4 ± 16.5 vs. 38.6 ± 10.1, P < 0.001), LA total emptying volume (17.9 ± 6.9 vs. 21.9 ± 5.9, P = 0.004), LA active emptying fraction (27.4 ± 16.5 vs. 38.6 ± 10.1, P < 0.001), LA active emptying volume (7.7 ± 3.6 vs. 9.4 ± 2.9, P = 0.013), LA passive emptying fraction (26.8 ± 10.2 vs. 33.2 ± 9.2, P = 0.002), and LA passive emptying volume (10.3 ± 4.9 vs. 12.5 ± 4.5, P = 0.029). There was a significant difference between the groups in terms of AEMD durations, except time interval from the onset of the P-wave on the surface ECG to the peak of the late diastolic wave (PA) of the tricuspid valve. The correlation analysis revealed that age and duration of disease were correlated with AEMD.

CONCLUSION

The current study reported that LA volume and mechanical functions degenerated and AEMD increased in patients with UC when compared to the control group. These findings demonstrate that UC may have effects on LA electromechanical functions related to duration of disease.

The Association of Serum Galectin-3 Levels with Atrial Electrical and Structural Remodeling

INTRODUCTION

Left atrial (LA) interstitial fibrosis is known to have a role in the initiation and maintenance of atrial fibrillation (AF). The role of galectin-3 in the pathogenesis of cardiac fibrosis has been demonstrated in previous studies. We aimed to determine whether serum galectin-3 level is associated with markers of atrial remodeling, including the extent of LA fibrosis detected by delayed enhancement magnetic resonance imaging (DE-MRI) and atrial electromechanical delay (AEMD) in paroxysmal AF patients with preserved left ventricular (LV) functions.

METHODS AND RESULTS

Thirty-three patients (58 [28-74] years, 51.5% male) with paroxysmal AF who underwent DE-MRI prior to cryoballoon-based AF ablation were included in the study. Serum galectin-3 levels were measured with ELISA. LA volume index (B ± SE: 0.424 ± 0.504, 95% CI: 0.560-2.627, P = 0.004) and serum galectin-3 levels (B ± SE: 0.549 ± 7.745, 95% CI: 16.874-47.550, P < 0.001) were found to be independently correlated with extent of LA fibrosis detected with DE-MRI in paroxysmal AF patients with preserved LV function. Correlation analysis between AEMD parameters and baseline characteristics showed that galectin-3 was significantly correlated with intra-left (ρ = 0.432, P = 0.012) and inter-AEMD (ρ = 0.395, P = 0.023). Duration of AF, LAD, and extent of LA fibrosis were also found to be significantly correlated with AEMD parameters.

CONCLUSION

This is a hypothesis-generating study pointing out that serum galectin-3 level is significantly associated with atrial remodeling in paroxysmal AF patients with preserved LV function. Further studies are necessary to provide exact pathophysiological mechanisms.

P-Wave Dispersion and Atrial Electromechanical Delay in Patients with Preeclampsia

OBJECTIVES

To investigate the duration of atrial electromechanical delay (EMD) and left atrial mechanical function in patients with preeclampsia.

MATERIALS AND METHODS

This study included 26 pregnant women with preeclampsia and 24 age-matched pregnant women without preeclampsia (control group). Atrial electromechanical coupling (PA) and intra-atrial and interatrial EMD were measured using tissue Doppler echocardiography. P-wave dispersion (PWD) was measured via 12-lead electrocardiography. All data were analyzed using SPSS v.15.0 for Windows (SPSS, Inc., Chicago, Ill., USA). Differences in continuous variables between groups were examined using a nonparametric Mann-Whitney U test. Correlation analysis was performed using Spearman's coefficient of correlation. Categorical values were compared using a χ2 test.

RESULTS

PA lateral and PA septal durations were significantly longer in the preeclampsia group than in the control group [74.6 ± 8.1 vs. 62.3 ± 5.3 ms (p < 0.001) and 59.7 ± 5.3 vs. 56.2 ± 4.9 ms (p = 0.005), respectively]. The duration of interatrial EMD and intra-atrial EMD in the preeclampsia group was significantly longer than in the control group [25.4 ± 4.6 vs. 13.2 ± 3.9 ms (p < 0.001) and 10.5 ± 1.9 vs. 7.1 ± 1.2 ms (p < 0.001), respectively]. PWD was significantly higher in patients with preeclampsia (43.1 ± 9.1 ms) than in the controls (37.6 ± 7.9 ms; p = 0.008). There was a significant correlation between PWD and interatrial EMD and intra-atrial EMD [r = 0.46 (p < 0.001) and r = 0.39 (p < 0.001), respectively].

CONCLUSION

The duration of atrial EMD and PWD was prolonged in patients with preeclampsia.

Cardiac hemodynamics and proinflammatory cytokines during biatrial and right atrial appendage pacing in patients with interatrial block

Purpose

Interatrial block (IAB) frequently coexists with sinus node disease and is considered a risk factor of left atrial dysfunction, atrial arrhythmias, and heart failure development. Conventional right atrial appendage (RAA) pacing impairs intra- and interatrial conductions and consequently prolongs P wave duration. Biatrial (BiA) pacing helps correct IAB, but its advantageous influence remains controversial. The aim of the study was to compare the effects of BiA and RAA pacing on cardiac hemodynamics and serum concentrations of inflammatory markers and neuropeptides.

Methods

Twenty-eight patients with IAB and preserved atrio-ventricular conduction treated with BiA pacing were studied. Standard invasive hemodynamic measurements were performed during BiA and RAA pacings. Furthermore, the influence of 1 week of BiA and RAA pacing on neuropeptides: atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) and markers of inflammation: high sensitivity C-reactive protein (hs-CRP), interleukin 6 (IL-6), and neopterin was examined.

Results

BiA pacing resulted in significant increase of cardiac output (CO) and reduction of pulmonary capillary wedge pressure. We demonstrated significantly lower concentrations of ANP, hs-CRP, IL-6, and neopterin after 1 week of BiA in comparison to RAA pacing. BNP levels remained unchanged.

Conclusions

BiA pacing in comparison to RAA pacing improves hemodynamic performance in patients with IAB and preserved atrio-ventricular conduction. BiA pacing is associated with reduction of ANP and markers of inflammation (hs-CRP, IL-6, and neopterin).

New echocardiographic techniques for evaluation of left atrial mechanics

Until recently the left atrium had been subordinate to the left ventricle, but cardiologists now recognize that left atrial (LA) function is indispensable to normal circulatory performance. Transthoracic two-dimensional (2D) and Doppler echocardiography can elucidate parameters of LA function non-invasively. Yet, with the advent of 2D speckle-tracking echocardiography, we are able to detect early LA dysfunction even before structural changes occur. This is pivotal in some common disease states, such as atrial fibrillation, hypertension, and heart failure, in which LA deformation parameters can influence clinical management. However, a unique standardized technique to investigate LA deformation needs to be validated.