Electromechanical Conduction Research Articles

Increased inter-atrial and intra-atrial conduction times in pediatric patients with non-alcoholic fatty liver disease.

The global incidence of pediatric non-alcoholic fatty liver disease (NAFLD) is rising, and it is linked to various potentially dangerous complications such as cardiovascular complications, particularly atrial fibrillation (AF). Atrial electromechanical conduction delay (EMD) has been reported as an early predictor for AF development. This study aimed to explore the link between NAFLD and the increased risk of AF development. This cross-sectional study was performed on 100 newly diagnosed NAFLD children (aged 14-18 years) as the patient group and 100 healthy individuals as a control group. Transthoracic echocardiography and simultaneous electrocardiography (ECG) recording were employed to estimate atrial electromechanical properties. EMD values were calculated for the inter-atrial, left intra-atrial, and right intra-atrial. Our results showed that pediatric patients with NAFLD exhibited significantly prolonged EMD values in the left and right intra-atrial as well as in inter-atrial regions compared to the control group (P = 0.03, P < 0.001, P < 0.01, respectively). Conclusion: Children with NAFLD show atrial electromechanical alterations that may presage AF in adulthood.

The Role of Galectin-3 Levels for Predicting Paroxysmal Atrial Fibrillation in Patients with Embolic Stroke of Undetermined Source.

Background/Objectives: Paroxysmal atrial fibrillation (PAF) is an important cause that is thought main potential factor in Embolic stroke of undetermined source (ESUS). Extended Holter ECG is an expensive and time-consuming examination. It needs another tools for predicting PAF in ESUS patients. In this study, serum galectin-3 levels, ECG parameters (PR interval, P wave time and P wave peak time) LA volume index, LA global peak strain and atrial electromechanical conduction time values were investigated for predicting PAF. Methods: 150 patients with ESUS and 30 volunteers for the control group were recruited to study. 48-72 h Holter ECG monitoring was used for detecting PAF. Patients were divided into two groups (ESUS + PAF and ESUS-PAF) according to the development of PAF in Holter ECG monitoring. Results: 30 patients with ESUS whose Holter ECG monitoring showed PAF, were recruited to the ESUS + PAF group. Other 120 patients with ESUS were recruited to the ESUS-PAF group. PA lateral, PA septum, and PA tricuspid were higher in the ESUS + PAF group (p < 0.001 for all). Serum galectin-3 levels were significantly higher in ESUS + PAF than in ESUS-PAF and control groups (479.0 pg/mL ± 435.8 pg/mL, 297.8 pg/mL ± 280.3 pg/mL, and 125.4 ± 87.0 pg/mL, p < 0.001, respectively). Serum galectin-3 levels were significantly correlated with LAVI, PA lateral, and global peak LA strain (r = 0.246, p = 0.001, p = 0.158, p = 0.035, r = -0.176, p = 0.018, respectively). Conclusion: Serum galectin-3 levels is found higher in ESUS patients which developed PAF and Serum galectin-3 levels are associated LA adverse remodeling in patients with ESUS.

Disturbed Atrial Conduction in Patients with Duchenne Muscular Dystrophy.

Duchenne muscular dystrophy (DMD)-related cardiomyopathy is associated with hemodynamic and conduction abnormalities and begins at an early age with subtle symptoms. The study population included 55 patients with DMD and 54 healthy controls. We compared electrocardiogram (ECG), conventional echocardiography, and tissue Doppler imaging (TDI) assessments between patients with DMD and healthy controls. Also, we investigated atrial electromechanical delay, which has not been previously studied in DMD patients. Mitral, septal, and tricuspid segments were analyzed by TDI. The mean age was 13.6 ± 2.5 years (range, 9.3-17.9 years) in the patient group and 12.8 ± 2.6 years (range, 8-17.5 years) in the control group (P = .1). Patients had higher heart rates, longer QTc intervals, and P-wave dispersion (PWD) than controls (P < .001, P = .004, P < .001, respectively). The patient group had larger left ventricular end-systolic dimension (P < .001), lower left ventricular ejection fraction (EF) (P < .001), MAPSE (P < .001), TAPSE (P < .001), and mitral-E/A (P = .029) values than control subjects. Myocardial performance index (P < .001) was higher, and the E'/A' ratio (P < .001) was lower at all 3 segments in the patient group. Also, atrial electromechanical delay was longer in the patient group at these segments (P < .001). Patients had significantly longer interatrial (P = .033) electromechanical conduction delays. EF was negatively correlated with atrial conduction time variables. We have shown deterioration in systolic and diastolic function in both ventricles, PWD, and atrial conduction in children with DMD. Patients with DMD may be at risk of atrial arrhythmias due to disturbed atrial conduction.

The Impact of Sodium-Glucose Cotransporter-2 Inhibitors on Atrial Electromechanical Conduction Time.

This study aims to explore the impact of sodium-glucose cotransporter-2 (SGLT-2) inhibitors, a newer class of oral antidiabetic drugs, on atrial electromechanical delay (EMD) in patients with type 2 diabetes mellitus (DM). This is particularly relevant given the significantly higher incidence of atrial fibrillation (AF) in diabetic patients compared to the general population. Atrial electromechanical delay is recognized as an important factor influencing the development of atrial fibrillation. This study included 30 type 2 DM patients (53.3% female, mean age 60.07 ± 10.03 years), initiating treatment with SGLT-2 inhibitors. The patients were assessed using echocardiography at baseline and again at 6 months, focusing on basic echocardiographic parameters and atrial electromechanical delay times (EMD) measured via tissue Doppler imaging. No significant changes were observed in intra-atrial EMD times. However, significant reductions were noted in interatrial EMD times, decreasing from 15.13 ± 5.87 ms to 13.20 ± 6.12 ms (P = 0.029). Statistically significant shortening occurred in lateral pulmonary acceleration (PA) times (from 58.73 ± 6.41 ms to 54.37 ± 6.97 ms, P < 0.001), septal PA times (from 50.90 ± 6.02 ms to 48.23 ± 5), and tricuspid PA times (from 43.60 ± 6.28 ms to 41.30 ± 5.60 ms, P = 0.003). Additionally, there was a significant reduction in the E/e' ratio from 8.13 ± 4.0 to 6.50 ± 2.37 (P = 0.003). SGLT-2 inhibitors might positively influence atrial electromechanical conduction, reducing DM-related functional impairments and the risk of arrhythmias, particularly AF.

Effects of childhood obesity on myocardial performance, autonomic and conduction properties of the heart.

Childhood obesity tends to persist into adulthood and associated with increase in developing ischemic and non-ischemic cardiovascular diseases. We aimed to evaluate the effect of obesity on cardiac functions, atrial electromechanical coupling, and heart rate response, which are considered to be predictors of atrial fibrillation and sudden cardiac arrest. Study population included 52 obese children and 52 healthy controls. We performed 12-lead electrocardiography, echocardiographic examination, and treadmill exercise testing. Mitral, septal, and tricuspid segments were analysed by tissue Doppler imaging. Myocardial performance index (p = 0.011, p < 0.001, and p = 0.001, respectively) was higher and E'/A' ratio (p = 0.011, p < 0.001, and p < 0.001, respectively) was lower in obese group than controls. Atrial electromechanical coupling was longer in the obese group at all three segments (p < 0.001, p = 0.009, and p = 0.04, respectively). They had significantly longer interatrial (p < 0.001) and intra-atrial (p = 0.003) electromechanical conduction delay. While chronotropic index was similar between two groups, heart rate reserve was lower in obese children than controls (p = 0.043). The 1st- and 2nd-minute heart rate recovery indices of the obese group were lower compared to controls (p < 0.001 and p = 0.03, respectively). Body mass index was positively correlated with intra- and inter-atrial conduction times, whereas it was negatively correlated with heart rate recovery indices. We showed a deterioration in the diastolic function, atrial conduction, and heart rate response properties in children with obesity. Given the prognostic importance of these parameters, obese patients are might be at risk for atrial fibrillation and severe dysrhythmias from a young age.

Electromechanical delay by speckle-tracking echocardiography: a novel tool for distinguishing between Brugada syndrome and isolated right bundle branch block

Abstract Background The electrocardiographic (ECG) definition of Brugada syndrome (BS) can be challenging because benign ECG abnormalities, such as right bundle branch block (RBBB), may mimic pathological ECG characteristics of BrS. However, although myocardial delay and deformation can be quantified by advanced imaging, it has not yet been used to differentiate between BrS and RBBB. Purpose The aim of this study was to characterize the electro-mechanical behavior of the heart of patients with type-1 BrS and subjects with isolated complete RBBB in order to differentiate these conditions. Methods In this two-center study, 66 subjects were analyzed by standard and speckle-tracking echocardiography (STE): 22 type-1 BrS, 24 isolated complete RBBB, and 20 healthy subjects. The participants were not treated by any drug potentially influencing myocardial conduction. Results Standard echocardiographic parameters did not differ among the groups. STE demonstrated that right ventricular (RV) mechanical dispersion (MD) was greater in RBBB as compared to BrS and controls (p&amp;lt;0.05). In patients with isolated RBBB, the greatest delay of RV time-to-peak longitudinal strain (TTP) was found in RV free-wall basal segments. Mean absolute deviations of TTP calculated for each left ventricular (LV) region were greater in patients with RBBB as compared to those with BrS and to controls with a localisation of the delay in LV antero-septal, anterior, lateral, and infero-septal basal segments (figure 1). Conclusions Advanced echocardiographic techniques may help to differentiate between BrS and RBBB. Indeed, STE allows to identify an electro-mechanical conduction delay in RBBB patients that is not found in patients affected by type-1 BrS. Electromechanical delay by STE Funding Acknowledgement Type of funding source: Public Institution(s). Main funding source(s): Italian Society of Cardiology

Interatrial Electromechanical Conduction Delay by ECG P-Wave and Echocardiographic Tissue Doppler Imaging for Diabetics Attending Merjan Teaching Hospital, A Comparison Study

Objectives: The objective was to study the atrial electromechanical P-wave electrocardiography (ECG)gated measurement of conduction times by tissue Doppler echocardiography (TDI) and left atrialmechanical function and volumes, the non-invasive predictors of atrial fibrillation, in diabetics. Methods:The study conducted by analytic case-control study and included 100 adult patients (63 men, 37 women;mean age 50.49 ±8.1 years), diagnosed with diabetes mellitus according to the criteria of the DiabetesAssociation of America, and 100 adults healthy (50 men; 50 women; average age 49.25 ±9.8 years) ascontrol. Tissue Doppler imaging (TDI) and conventional echocardiography study was done. Assessment ofelectromechanical delay was done with the onset of the surface ECG P-wave to the systolic a?-wave onset onTDI of the AV valve annulus of the septum, left and right ones. Using the disk method, the left atrial volumeswere assessed. The mechanical function and volumes of the left atrium were computed. Results: The E/Aand e?/a? mitral ratio was assessed by the left and septal annuli were the mean difference significantly lessin diabetics than in controls (P=0.031) and (P=0.034 correspondingly. The electromechanical inter-atrialand intra-atrial delay were significantly greater within the diabetics, contrasted to controls (P&lt;0.001) and(P=0.003) correspondingly. Volumes of active left atrial emptying (LAAEV) and the ratio of active leftatrial ejection (LAAEF) were significantly higher in diabetics in comparison with controls (P =0.002) and(P&lt;0.001) correspondingly. Both were significantly correlated to E/A and e?/a?. Conclusions: In diabetics,conduction times of the atrium by TDI and the dispersion of the P-wave by surface ECG were longer.Furthermore, the mechanical functions and volumes of the left atrium were affected by altering diastolicfunction in diabetics.

Electromechanical delay by speckle-tracking echocardiography: A novel tool to distinguish between Brugada syndrome and isolated right bundle branch block

BackgroundThe electrocardiographic (ECG) definition of Brugada syndrome (BS) can be challenging because benign ECG abnormalities, such as right bundle branch block (RBBB), may mimic pathological ECG characteristics of BrS. However, although myocardial delay and deformation can be quantified by advanced imaging, it has not yet been used to differentiate between BrS and RBBB. The aim of this study was to characterize the electro-mechanical behavior of the heart of patients with type-1 BrS and isolated complete RBBB in order to differentiate these conditions. MethodsIn this two-center study, 66 subjects were analyzed by standard and speckle-tracking echocardiography (STE): 22 type-1 BrS, 24 isolated complete RBBB, and 20 healthy subjects. The participants were not treated by any drug potentially influencing myocardial conduction. ResultsStandard echocardiographic parameters did not differ among the groups. The greatest right ventricular (RV) mechanical dispersion was found in RBBB. Mean absolute deviations (MADs) of time-to-peak longitudinal strain calculated for each left ventricular (LV) region were greater in patients with RBBB as compared to BrS (p < .01). No differences were found between BrS and controls (p = .36). MADs in the basal segments in RBBB group were greater than MADs found in BrS group and controls (37.3 ms vs. 26.7 ms and 29.0 ms, respectively, p < .05). The greatest differences were found in the antero-septal, anterior, lateral, and infero-septal basal segments. ConclusionsAdvanced echocardiographic techniques may help to differentiate between BrS and RBBB. Indeed, STE allows to identify an electro-mechanical conduction delay in RBBB patients that is not found in patients affected by type-1 BrS.

Acute Effects of Red Bull Energy Drinks on Atrial Electromechanical Function in Healthy Young Adults

Energy drinks (EDs) are widely consumed by adolescents and young adults. Almost all kinds of arrhythmias have been reported following EDs consumption, most of which is atrial fibrillation (AF). Atrial conduction time prolongation and heterogeneous sinusal impulses propagation to the atriums are the key electrophysiological mechanisms leading AF. We aimed to evaluate the acute effects of Red Bull ED ingestion on atrial electromechanical conduction times in healthy young adults. After a 12-hour fasting, 54 healthy young adults consumed 330 mL of Red Bull ED. Atrial electromechanical coupling (PA), intra-atrial electromechanical delay (intra-AEMD), and interatrial electromechanical delay (inter-AEMD) were measured at baseline and 2-hour after Red Bull ED ingestion by echocardiographic tissue-Doppler imaging (TDI) method. PA-lateral (49.7 ± 11.2 vs 54.1 ± 11.0 msn, p = 0.001) and PA-septal (40.8 ± 9.1 vs 43.7 ± 10.5 msn, p = 0.032) times were statistically significantly prolonged after Red Bull ED ingestion. There was also a statistically significant increase in the duration of inter-AEMD (14.4 ± 10.6 vs 18.1 ± 8.5 msn, p = 0.010) after ED ingestion. It was showed that even a single can of ED can acutely increase atrial electromechanical conduction times in young adults. These findings may be the cause of ED-associated AF.

Comparison of atrial fibrillation predictors in patients with acute coronary syndrome using ticagrelor or clopidogrel

Background/aimTicagrelor is a drug widely used in patients with acute coronary syndromes (ACS) that specifically increases the plasma level of adenosine, which is likely to cause atrial fibrillation (AF). Therefore, in this study we aimed to investigate the electrocardiographic and echocardiographic predictors of AF development after P2Y12 receptor antagonists in ACS patients.Materials and methodsThis cross-sectional study included 831 patients with ACS (486 [58.5%] with ST elevated myocardial infarction [STEMI] and 345 [41.5%] with non-ST elevated myocardial infarction [NSTEMI]). Patients were divided into ticagrelor (n = 410) and clopidogrel (n = 421) groups. P wave properties including P wave dispersion and atrial electromechanical conduction properties were measured as AF predictors with surface ECG and tissue Doppler imaging.ResultsBaseline characteristics such as age, sex, heart rate, blood pressure, and laboratory parameters were almost the same in the ticagrelor and clopidogrel groups. The statistical analysis showed no significant difference in P wave dispersion (PWD) between ticagrelor and clopidogrel groups (40.98 ± 12 ms versus 40.06 ± 12 ms, P = 0.304). Subgroups analysis according to ACS types also showed no significant difference in PWD (NSTEMI: 41.16 ± 13.8 ms versus 40.76 ± 13.55 ms, P = 0.799; STEMI: 40.9 ± 12.62 ms versus 39.19 ± 11.18 ms, P = 0.132). In addition, we did not find significant difference in atrial electromechanical delay (EMD) with tissue Doppler imaging (interatrial EMD 24.11 ± 3.06 ms versus 24.46 ± 3.23 ms, P = 0.279).ConclusionIn conclusion, we did not find any difference in detailed electrocardiographic and echocardiographic parameters as AF predictors between ticagrelor and clopidogrel groups in patients with ACS.

P2450The atrial electromechanical conduction delay with ultrasound based two-dimensional speckle-tracking predicts very late recurrence following catherter ablation for atrial fibrillation

Abstract Background/Introduction Long-term efficacy following catheter ablation (CA) of atrial fibrillation (AF) remains unknown. Left atrial (LA) reverse remodeling following CA may be important to reduce the risk of very late recurrence (VLR). Purpose We hypothesize that improved mechanical conduction delay with myocardial strain is associated with LA reverse remodeling indicates efficacy following AF ablation. This study aimed to investigate the clinical utility of mechanical conduction delay to predict VLR in patients with AF undergoing CA. Methods We enrolled 114 consecutive patients undergoing initial CA in patients with AF from January 2012 to February 2014. 20 patients were excluded due to poor echocardiographic image quality. 38 patients had AF recurrence within 12 months after CA. Finally, 54 patients (age 62 years, 13 female, 15 persistent AF) were analyzed. Trans-thoracic echocardiography (TTE) was performed within 24 hours as baseline, and every 6–12 months following the initial CA as follow-up. We compared the TTE data with baseline and latest test when sinus rhythm was maintained. To assess atrial electromechanical conduction delay, we adopted a parameter based on speckle tracking echocardiography (EMT-ε), which was defined as the interval from the P- wave onset to the peak late diastolic longitudinal strain in the basal lateral wall of LA (Figure). Results Eleven patients had VLR after CA. In patients with VLR, left atrial volume index (LAVI) at baseline was significantly higher than those without VLR (49±17 vs 35±14 ml/m2, P&lt;0.05). EMT-ε had no significant difference between two groups (225±52 vs 208±49 ms, P=NS). During 58±22 months, LAVI and EMT-ε were significantly improved (LAVI: 38±16 vs 33±14 ml/m2, EMT-ε: 215±48 vs 197±45 ms, P&lt;0.05, respectively). The change of LAVI had no significant difference between two groups (−2 (−10, 4) vs 33 (−13, 6) ml/m2, P=NS). EMT-ε shortening was significantly greater in AF-free patients than patients with VLR (−27 (−66, −3) vs 23 (−1, 79) ms, P&lt;0.01). At a cut-off value of −9 ms, the change of EMT-ε predicted VLR with sensitivity (100%) and specificity (68.9%). Conclusion(s) The atrial electromechanical conduction delay could predict VLR after CA in patients with AF.

Electro-Mechanical Conductance Modulation of a Nanopore Using a Removable Gate.

Ion channels form the basis of information processing in living cells by facilitating the exchange of electrical signals across and along cellular membranes. Applying the same principles to man-made systems requires the development of synthetic ion channels that can alter their conductance in response to a variety of external manipulations. By combining single-molecule electrical recordings with all-atom molecular dynamics simulations, we here demonstrate a hybrid nanopore system that allows for both a stepwise change of its conductance and a nonlinear current-voltage dependence. The conductance modulation is realized by using a short flexible peptide gate that carries opposite electric charge at its ends. We show that a constant transmembrane bias can position (and, in a later stage, remove) the peptide gate right at the most-sensitive sensing region of a biological nanopore FraC, thus partially blocking its channel and producing a stepwise change in the conductance. Increasing or decreasing the bias while having the peptide gate trapped in the pore stretches or compresses the peptide within the nanopore, thus modulating its conductance in a nonlinear but reproducible manner. We envision a range of applications of this removable-gate nanopore system, e.g. from an element of biological computing circuits to a test bed for probing the elasticity of intrinsically disordered proteins.

Left atrial electromechanical conduction time predicts atrial fibrillation in patients with mitral stenosis: a 5-year follow-up speckle-tracking echocardiography study.

Prolonged left atrial electromechanical conduction time is related with atrial electrical remodeling, and is predictive of the development of atrial fibrillation. The aim of our study was to examine whether left atrial electromechanical conduction time (EMT) and left atrial strain as measured by speckle tracking echocardiography (STE) are predictors for the development of atrial fibrillation (AF) in patients with mitral stenosis (MS) at 5-year follow-up. A total of 81 patients (61% females; mean age 38.1 ± 12.1years) with mild or moderate MS of rheumatic origin according to ACC/AHA guidelines who were in sinus rhythm, and were asymptomatic or have NYHA class 1 symptom were included in the study. AF was searched by 12-lead electrocardiograms or 24-h Holter recordings during follow-up period. Atrial electromechanical conduction time (EMT), peak atrial longitudinal strain (PALS) and peak atrial contraction strain (PACS) were measured by STE. EMTs was defined as the interval between the onset of P-wave to the peak late diastolic longitudinal strain in the basal lateral and septal wall. During the follow-up period of 5 years (mean follow-up duration, 48.2 ± 13.3months), 30 patients (37%) developed AF on standard 12-lead ECG or at their 24-h Holter recording. At follow-up, patients who developed AF were older than patients without AF (42.4 ± 11.3 vs. 35.6 ± 11.9, p = 0.014). Mitral valve area (MVA) (1.39 ± 0.14 vs. 1.48 ± 0.18, p = 0.03), PALS (13.4 ± 4.6 vs. 19 ± 5.2, p < 0.001) and PACS (6 ± 2.7 vs. 8.4 ± 3.8, p = 0.004), were lower in patients who developed AF than in patients who did not develop. However, EMTs-Septal (208.2 ± 28.4 vs. 180.2 ± 38, p = 0.001), and EMTs-Lateral (247.1 ± 27.6 vs. 213.3 ± 43.5, p < 0.001) were longer in patients with AF than in patients without. In multivariate Cox regression analysis, PALS and left atrial EMTs-Lateral were independent predictors for development of AF at follow-up. In patients with mitral stenosis, left atrial strain and electromechanical conduction time in the lateral wall during the long term follow-up period are predictive for the development of atrial fibrillation. Speckle tracking echocardiography is a basic and easily-implemented method based on left atrial parameters which may be helpful for early detection of atrial fibrillation in patients with mitral stenosis.

Early Changes in Atrial Electromechanical Coupling in Patients with Hypertension: Assessment by Tissue Doppler Imaging.

Background:Hypertension (HT) is associated with atrial electrophysiological abnormalities. Echocardiographic pulsed wave tissue Doppler imaging (TDI) is one of the noninvasive methods for evaluation of atrial electromechanical properties. The aims of our study were to investigate the early changes in atrial electromechanical conduction in patients with HT and to assess the parameters that affect atrial electromechanical conduction.Methods:Seventy-six patients with HT (41 males, mean age 52.6 ± 9.0 years) and 41 controls (22 males, mean age 49.8 ± 7.9 years) were included in the study. Atrial electromechanical coupling at the right (PRA), left (PLA), interatrial septum (PIS) were measured with TDI. Intra- (right: PIS-PRA, left: PLA-PIS) and inter-atrial (PLA-PRA) electromechanical delays were calculated. Maximum P-wave duration (Pmax) was calculated from 12-lead electrocardiogram.Results:Atrial electromechanical coupling at PLA (76.6 ± 14.1 ms vs. 82.9 ± 15.8 ms, P = 0.036), left intra-atrial (10.9 ± 5.0 ms vs. 14.0 ± 9.7 ms, P = 0.023), right intra-atrial (10.6 ± 7.8 ms vs. 14.5 ± 10.1 ms, P = 0.035), and interatrial electromechanical (21.4 ± 9.8 ms vs. 28.3 ± 12.7 ms, P = 0.003) delays were significantly longer in patients with HT. The linear regression analysis showed that left ventricular (LV) mass index and Pmax were significantly associated with PLA (P = 0.001 and P = 0.002, respectively), and the LV mass index was the only related factor for interatrial delay (P = 0.001).Conclusions:Intra- and interatrial electromechanical delay, PLA were significantly prolonged in hypertensive patients. LV mass index and Pmax were significantly associated with PLA, and the LV mass index was the only related factor for interatrial delay. The atrial TDI can be a valuable method to assess the early changes of atrial electromechanical conduction properties in those patients.

Atrial Electromechanical Properties in Inflammatory Bowel Disease

There is much evidence linking inflammation to the initiation and continuation of atrial fibrillation (AF). Inflammatory bowel diseases (IBD), including ulcerative colitis (UC) and Crohn's disease (CD), are chronic systemic inflammatory disorders. Atrial electromechanical delay (EMD) has been known as an early marker of AF. The objectives of this study were to evaluate the atrial electromechanical properties in patients with IBD. Fifty-two patients with IBD and 26 healthy controls were recruited in the study. Twenty-five of patients with IBD were on active period, and the remaining 27 were on remission period. Atrial electromechanical properties were measured by using transthoracic echocardiography and tissue Doppler imaging and simultaneous surface ECG recording. Interatrial EMD, left intraatrial EMD, and right intraatrial EMD were calculated. Patients on activation with IBD had significantly prolonged left and right intraatrial EMDs and interatrial EMD compared to patients on remission (P = 0.048, P = 0.036, P < 0.001, respectively) and healthy controls (P < 0.001, for all comparisons). Left and right intraatrial EMDs and interatrial EMD were also found to be higher when patients on remission with IBD compared with healthy controls. No statistical difference was observed between UC and CD in terms of inter- and intraatrial EMDs. Atrial electromechanical conduction is prolonged in IBD, and exposure to chronic inflammation may lead to structural and electrophysiological changes in the atrial tissue that causes slow conduction. Measurement of atrial EMD parameters might be used to predict the risk for the development of AF in patients with IBD.

Evaluation of P-Wave Dispersion, Diastolic Function, and Atrial Electromechanical Conduction in Pediatric Patients with Subclinical Hypothyroidism.

This study aimed to evaluate ventricular diastolic dysfunction, inter- and intraatrial conduction delay, and P-wave dispersion in pediatric patients with subclinical hypothyroidism. The study comprised a total of 30 pediatric patients with subclinical hypothyroidism (SH) (mean age 7.8 ± 3.2 years) and 30 healthy children (mean age 8.4 ± 3.6 years) as the control group. A SH diagnosis was made in the event of increased serum thyroid-stimulating hormone (TSH) and decreased serum free triiodothyronine (T3 ) and free thyroxine (T4 ) concentrations. Conventional Doppler imaging (TDI) showed low mitral early diastolic E-wave velocity and E/A ratio (P < 0.001) and significantly higher mitral late diastolic A-wave velocity (P = 0.001) in hypothyroidism patients. Moreover, patients with hypothyroidism had significantly lower left ventricular (LV) septal Em velocity and Em /Am ratios compared with the control group (P < 0.001), whereas Am velocity was higher in hypothyroidism patients (P = 0.018). LV lateral Em velocity and Em /Am ratio were significantly lower in patients with hypothyroidism compared with the control group (P < 0.001). With regard to atrial electromechanical conduction, atrial electromechanical delay (PA) lateral, PA septum, PA tricuspid, and each of interatrial and intraatrial conduction delay were significantly prolonged in hypothyroidism patients as compared with the control group (P < 0.001, P < 0.001, P = 0.023, P = 0.002, and P = 0.003, respectively). P-wave dispersion was significantly different in the pediatric patients with hypothyroidism (P < 0.001). This study demonstrated atrial electromechanical conduction delay, abnormal P-wave dispersion, and ventricle diastolic dysfunction in pediatric patients with hypothyroidism.

Clinical Utility of Atrial Electromechanical Conduction Time Measured with Speckle Tracking Echocardiography after Catheter Ablation in Patients with Atrial Fibrillation: A Validation Study with Electroanatomical Mapping.

Our recent report demonstrated that atrial electromechanical conduction time (EMT-ε) measured with speckle tracking echocardiography could predict cardiac events in patients with pathological left ventricular hypertrophy. This study aimed to validate EMT-ε by comparison with electroanatomical mapping and to investigate the clinical utility of EMT-ε in patients with atrial fibrillation (AF) undergoing catheter ablation. Forty-six patients with preserved LV ejection fraction (LVEF ≥ 50%) undergoing pulmonary vein isolation (PVI) for AF were studied. Atrial electrical conduction delay was determined by measuring atrial electrical activation time (EAT) using three-dimensional electroanatomical mapping just after PVI. Echocardiographic parameters were acquired within 24 hours and at 6 months after PVI. The study also included 10 control subjects. AF patients had a larger left atrial (LA) volume index (LAVI) and more prolonged EMT-ε compared with control subjects. According to the validation study, EAT was closely related to EMT-ε and a', and this association was independent of LAVI and the presence of persistent AF (EMT-ε: R(2) = 0.342, P < 0.0001, a': R(2) = 0.337, P < 0.0001). At 6 months after PVI, LAVI and EMT-ε were significantly improved. During continued follow-up beyond 6 months (total follow-up, 26 ± 12 months), the EMT-ε shortening at 6 months after PVI was significantly greater in AF-free patients than patients with AF recurrence. This study suggested that the EMT-ε could be a useful echocardiographic marker of LA electromechanical abnormalities in patients with AF.

Evaluation of atrial electromechanical conduction delay in case of hemodynamically insignificant rheumatic heart disease: A tissue Doppler study.

Atrial electromechanical delay (AEMD) that reflects delayed conduction may show us the clinical reflection of pathological changes in the atria. The main objective of the present study is to investigate AEMD in patients who had previous rheumatic carditis but without hemodynamically significant valvular disease. A total of 40 patients, previously diagnosed as rheumatic carditis but without significant valvular stenosis/regurgitation and atrial enlargement; and 39 age- and-sex matched controls were enrolled for the present study. Parameters of AEMD (lateral mitral annulus electromechanical delay, septal mitral annulus electromechanical delay and lateral tricuspid annulus electromechanical delay) were measured with tissue Doppler echocardiography and left intra-atrial and inter-atrial conduction times were calculated accordingly. A 24h ambulatory Holter monitoring was used in both groups to detect atrial fibrillation episodes and quantify atrial extrasystoles. Parameters of AEMD, including left intra-atrial and inter-atrial conduction times of subjects in the study group were longer compared to the control group (23.7 ± 7.0 vs. 18.3 ± 6.2). Increased AEMD is observed in patients with previous rheumatic carditis and no significant valvular stenosis/regurgitation and atrial enlargement, which may partly explain the increased incidence of atrial fibrillation observed in these patients.

Evaluating functional capacity, and mortality effects in the presence of atrial electromechanical conduction delay in patients with systolic heart failure.

Objective:Atrial functions are relatively suppressed in heart failure (HF). We aimed to investigate the associations of intra- and inter-atrial electromechanical conduction delay (EMCD) with functional class and mortality over a 12-month follow-up period.Methods:The prospective study included 65 patients with systolic HF and 65 healthy subjects with normal sinus rhythm. Left ventricular (LV) systolic functions and left atrial (LA) dimensions and volumes were evaluated by transthoracic echocardiography. Tissue Doppler imaging (TDI) signals at the lateral border of the mitral annulus (lateral PA’), septal mitral annulus (septal PA’), and tricuspid annulus (tricuspid PA’) were measured. Intra- and inter-atrial EMCD were calculated.Results:Mitral inflow velocities were studied using pulsed-wave Doppler after placing the sample volume at the leaflets’ tips. The peak early (E wave) and late (A wave) velocities were measured. The septal annular E/E’ ratio was relatively higher and lateral, septal, and right ventricular S, E’, and A’ waves were significantly lower in the HF group than in the control group (12.49±6.03 – 7.16±1.75, pE/E’ <0.0001). Intra-atrial EMCD was detected as 117.5 ms and inter-atrial EMCD as 127.5 ms in patients with prolonged atrial EMCD. A significant increase was found in prolonged intra- and inter-atrial EMCD according to functional capacity increase (p=0.012 and p=0.031, respectively). The incidence of mortality was significantly higher in patients with prolonged atrial EMCD (p=0.025), and 5 patients in the HF group died during the study over the 12-month follow-up period.Conclusions:In this study, we found a relationship between prolonged atrial conduction time and increased functional class and mortality in patients with systolic HF. (Anatol J Cardiol 2016; 16: 579-86)

The impact of cryoballoon-based catheter ablation on left atrial structural and potential electrical remodeling in patients with paroxysmal atrial fibrillation.

While atrial fibrillation (AF) begets AF via structural, contractile, and electrical remodeling, it was shown that successful radiofrequency ablation of AF has effectively reversed left atrial (LA) remodeling. However, there was little data regarding the efficacy of cryoablation on LA remodeling. Herein, we aimed to assess the impact of cryoablation on LA structural and potential electrical remodeling in paroxysmal AF patients. A total of 41 symptomatic patients with non-valvular paroxysmal AF underwent their first catheter ablation via cryoballoon technique. All patients had transthoracic echocardiography before, 6 and 12 months after cryoablation. LA volume index (LAVI), left intra-, right intra-, and inter-atrial electromechanical conduction delay (AEMD) were calculated in all patients. Postprocedural first 3 months was accepted as blanking period. All 179 pulmonary veins were isolated successfully in 41 patients with no major complication. During median 18 months (12-20 months) follow-up, recurrent atrial arrhythmia was found in nine patients (21.9%). In multivariate Cox regression analysis, only early recurrence was found as the independent predictor of late recurrence. At 12th month visit compared to baseline, there was no change in LAVI (p = 0.647) but significant increase in left intra- and inter-AEMD (p < 0.05). However, in non-recurrent group, both LAVI (30.63 ± 3.6 to 28.42 ± 3.63, p < 0.001), left intra-AEMD (18.75 ± 8.77 to 12.5 ± 4.65, p < 0.001), and inter-AEMD (25.2 ± 13.2 to 18.84 ± 8.52, p < 0.001) were significantly decreased. Our study findings revealed that successful cryoballoon-based AF ablation yields LA structural and potential electrical reverse remodeling. However, LA remodeling process cannot be halted by cryoablation in patients with AF recurrence during follow-up.