Atrial Conduction Time Research Articles

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.

Effect of Aging on Left Atrial Compliance and Electromechanical Properties in Subjects Without Structural Heart Disease

Aging is associated with changes in left atrial (LA) structure and function. The present study aimed at describing the effect of aging on LA properties in a large cohort of subjects without structural heart disease. We divided 386 subjects (mean age 58 years [range 16 to 91]; 188 men [49%]) clinically referred for echocardiography according to age groups. The P-wave dispersion (PWD), reflecting total atrial conduction time, was measured on a 12-lead surface electrocardiogram as the difference between maximum and minimum P-wave duration. The PA-TDI duration reflecting the total atrial conduction time was measured on tissue Doppler imaging (TDI) as the time between onset of P wave on surface electrocardiogram to peak A'-wave velocity. Two-dimensional speckle-tracking echocardiography was used to assess LA reservoir function, reflecting LA compliance. In the overall population, mean PWD, PA-TDI, and LA reservoir strain were 43 ± 12ms, 129 ± 27ms, and 36 ± 13%, respectively. Increasing age was independently associated with prolonged PWD (β= 0.161; p <0.001), PA-TDI (β= 0.476; p <0.001), and reduced LA reservoir strain (β=-0.259; <0.001), suggesting age-related fibrotic changes of the LA myocardium. The association between age and LA reservoir strain was modulated by body mass index (β=-0.582; p <0.001) and LA volume index (β=-0.117; p= 0.014). In conclusion, aging is associated with longer PWD and PA-TDI duration along with a decrease in LA reservoir function. Obesity and larger LA volumes are independently associated with reduced LA compliance.

Assessment of atrial conduction times in prediabetic patients with coronary artery disease.

Objective:Prediabetes is a dysglycemic state and is associated with subtle myocardial injury and dysfunction. We evaluated atrial conduction times (ACTs) and atrial electromechanical delays (EMDs) in prediabetic patients with coronary artery disease (CAD).Methods:In the present study, we recruited 128 consecutive patient candidates (40 euglycemic, 48 prediabetic, and 40 diabetic patients) for coro- nary artery bypass grafting. ACTs were measured using tissue Doppler imaging (TDI). The time intervals between the beginning of the P wave in the surface electrocardiogram and the peak of the a¢ wave in TDI (PA) in the septal and lateral mitral annuli and the lateral tricuspid annulus were measured and termed as “septal PA,” “lateral PA,” and “right ventricular (RV) PA,” respectively. The differences between lateral and septal PA, septal and RV PA, and lateral and RV PA were termed as “left intra-atrial EMD,” “right intra-atrial EMD,” and “inter-atrial EMD” respectively.Results:Septal PA, lateral PA, RV PA, left and right intra-atrial EMDs, and inter-atrial EMD were not statistically different between these three groups. Furthermore, multivariable linear regression models, adjusted for potential confounders, showed that glycemic state was not associated with ACTs, left and right intra-atrial EMDs, and inter-atrial EMD.Conclusion:There were no significant differences between the euglycemic, prediabetic, and diabetic patients with CAD regarding ACTs and atrial EMDs.

RESULTS OF CONTINUOUS POSITIVE UPPER AIRWAY PRESSURE TREATMENT IN PATIENTS WITH ATRIAL FIBRILLATION AND OBSTRUCTIVE SLEEP APNEA

Aim. Evaluation of CPAP treatment (continuous positive upper airway pressure) in obstructive sleep apnea patients (OSA) and atrial fibrillation (AF) in comparison with antiarrhythmic medication therapy. Material and methods. Totally, 36 patients included (58% males, mean age 61±11 y.) with AF and definite OSA by the data from cardiorespiratory monitoring. In 6 (17%) patients there was moderate level of respiratory disorders and in 30 (83%) — severe. Twenty four (67%) patients had paroxysmal and 12 (33%) — persistent AF. All patients, to retain sinus rhythm and prevent AF relapses, were taking antiarrhythmic medications (AAM). Therapy by CPAP was recommended to all patients, but after familiarization nights (1-3), 18 agreed to continue this type of treatment at home (group 1), other 18 (group 2) were unable to apply CPAP due to low tolerance. During 12 month follow-up, comparative analysis was done, of AAM efficacy in both groups of patients. Groups did not differ significantly by the medications being taken. Results. With CPAP therapy, in group 1 most patients (12, 67%) during 12 months did not develop AF relapses, and in the group 2 — only 6 (33%) did not have AF. It is worthy to mention than group 1 patients had potentially less chance for antiarrhythmic therapy success, if to consider traditional risk factors of AF, as they had higher body mass (body mass index 39,5 kg/m2 versus 34, p=0,07), more severe sleep respiration disorders (apnea-hypopnea index 50,8 events per hour versus 37,4, p=0,09) and larger left atrium (82 mL versus 60,5, p=0,02) comparing to group 2 patients. During 3-month CPAP treatment, in group 1 patients a significant decrease of P-wave dispersion was noted, by 30,8% (р=0,05). Conclusion . Therapy with CPAP in moderate and severe OSA makes it to more than two times (from 33% to 67%) increase efficacy of antiarrhythmic drug treatment for AF. One of the mechanisms of antiarrhythmic action of CPAP againts AF might be a decrease of atrial conduction time dispersion.

Atrial conduction times and left atrial mechanical functions and their relation with diastolic function in prediabetic patients.

Background/AimsThe aim of this study was to investigate atrial conduction times and left atrial mechanical functions, the noninvasive predictors of atrial fibrillation, in prediabetic patients with impaired fasting glucose (IFG) and impaired glucose tolerance (IGT).MethodsStudy included 59 patients (23 males, 36 females; mean age 52.5 ± 10.6 years) diagnosed with IFG or IGT by the American Diabetes Association criteria, and 43 healthy adults (22 males, 21 females; mean age 48.5 ± 12.1 years). Conventional and tissue Doppler echocardiography were performed. The electromechanical delay parameters were measured from the onset of the P wave on the surface electrocardiogram to the onset of the atrial systolic wave on tissue Doppler imaging from septum, lateral, and right ventricular annuli. The left atrial volumes were calculated by the disk method. Left atrial mechanical functions were calculated.ResultsThe mitral E/A and E’/A’ ratios measured from the lateral and septal annuli were significantly lower in the prediabetics compared to the controls. The interatrial and left atrial electromechanical delay were significantly longer in prediabetic group compared to the controls. Left atrial active emptying volume (LAAEV) and fraction (LAAEF) were significantly higher in the prediabetics than the controls. LAAEV and LAAEF were significantly correlated with E/A, lateral and septal E’/A’.ConclusionsIn the prediabetic patients, the atrial conduction times and P wave dispersion on surface electrocardiographic were longer before the development of overt diabetes. In addition, the left atrial mechanical functions were impaired secondary to a deterioration in the diastolic functions in the prediabetic patients.

Evaluation of Atrial Conduction Times, Epicardial Fat Thickness and Carotid Intima-Media Thickness in Patients With Ankylosing Spondylitis.

This study aims to determine the relationship between atrial electromechanical delay (EMD), carotid intima-media thickness (CIMT), and epicardial fat thickness (EFT) in ankylosing spondylitis (AS), which has a complicated inflammatory nature. The study population included 42 consecutive patients with AS (28 males, 14 females; mean age 39.3±8.5 years; range 22 to 60 years) and 40 healthy subjects as controls (24 males, 16 females; mean age 37.2±8.7 years; range 22 to 60 years) (p>0.05). All patients underwent a standard tissue Doppler echocardiography to assess the left ventricular diastolic dysfunction, atrial EMD, CIMT, and EFT. All values were compared between the groups. Interatrial (29.5±5.8 ms vs. 17.9±5.3 ms) left and right intraatrial EMD (18.2±4.6 ms and 11.7±3.5 ms vs. 11.9±3.2 ms and 7.1±3.2 ms, respectively) intervals were longer in AS patients than in healthy controls (all p<0.001). Left and right CIMT (0.50±0.11 mm and 0.44±0.06 mm vs. 0.51±0.11 mm and 0.43±0.04 mm, respectively) and EFT (0.73±0.15 cm and 0.63±0.07 cm) values were higher in AS patients than in healthy controls (all p<0.01). To our best knowledge, this is the first report evaluating the atrial EMD, CIMT, and EFT values together in AS patients. As indicators of cardiovascular involvement, all parameters were higher in AS patients.

Total atrial conduction time to predict occult atrial fibrillation after cryptogenic stroke

Insertable cardiac monitor (ICM) increases the detection rate of occult atrial fibrillation (AF) after cryptogenic stroke. The aim of this study was to evaluate the prognostic significance of total atrial conduction time (TACT) assessed by tissue Doppler imaging (PA-TDI interval) to predict AF presence in patients with cryptogenic stroke. Ninety patients (57.7±12.3years, 48% women) after acute cryptogenic stroke and ICM implantation were prospective recruited at four centers for continuous rhythm monitoring. In all patients, TACT was measured by PA-TDI interval via echocardiography. Patients were followed up (331±186days) for detection of AF (defined by episode lasting ≥30s). AF was detected in 16 patients (18%) during follow-up (331±186days). The median period to AF detection was 30days (q1-q3; 16-62days). Patients who exhibited occult AF were characterized by significantly longer PA-TDI intervals (154.7±12.6 vs. 133.9±9.5ms, p<0.0001). The cut-off value of PA-TDI interval at 145ms demonstrated sensitivity and specificity for AF detection of 93.8 and 90.5%, respectively. In multivariate analysis, CHA2DS2-VASc score (HR 1.96 per 1 point, p<0.01) and longer PA-TDI interval (HR 4.05 per 10ms, p<0.0001) were independent predictors of occult AF. Our data suggest that measurement of TACT could help to predict future AF detection in patients with cryptogenic stroke. The clinical importance of prolonged rhythm monitoring or indication of direct anticoagulation therapy after cryptogenic stroke based on TACT should be further investigated.

Left atrial changes in early stages of heart failure with preserved ejection fraction.

Increased left atrial (LA) mass was introduced as a compensatory mechanism in heart failure (HF) patients. Furthermore, atrial conduction time and LA emptying fraction is are deteriorated in HF with preserved ejection fraction (HFpEF). The aim of this study was to assess the early LA changes in HFpEF patients. In 79 consecutive patients with HFpEF (age 61±8years, NYHA class I-III, LV EF ≥45%), a complete 2-dimensional, M-mode, and Doppler echocardiographic study was performed. According to the diastolic dysfunction (DD), patients were divided into three groups: Group I-29 healthy subjects (control group); Group II-HFpEF patients with mild DD; and Group III-HFpEF patients with moderate DD. The LV mass was increased (P<.05), septal s', lateral s', septal and lateral MAPSE were decreased (P<.05, for all), E/e' ratio was increased (P<.001), LA mass and minimal volume were increased (P<.001, P<.05), LA emptying fraction was decreased (P<.05), and LA dyssynchrony was deteriorated (P<.05) in patients with mild DD compared to controls. These changes were of the same nature in patients with moderate LV DD. In early stage of DD, in patients with HFpEF, in addition to LV hypertrophy and compromised LV longitudinal systolic function, the LA emptying fraction is reduced, LA mass and LAV min are increased and LA dyssynchrony is significant, despite normal LA dimensions. These findings suggest early LA function deterioration irrespective of normal cavity measurements, hence a need for optimum therapy.

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.

Decreased left atrial strain parameters are correlated with prolonged total atrial conduction time in lone atrial fibrillation

To investigate left atrium (LA) strain properties of patients with lone atrial fibrillation (LAF) and to assess relationships between LA strain parameters and total atrial conduction time measured with tissue Doppler imaging (PA-TDI). The study population consisted of 53 patients with LAF. The control group was comprised of 50 normal volunteers. Conventional echocardiography indices were measured. Mitral annular velocities and PA-TDI were assessed with TDI. Two-dimensional speckle-tracking echocardiography (2D-STE) was used to assess LA segmental strain and strain rate. Compared with the control group, PA-TDI was significantly prolonged and LA myocardial Ss, SRs, Sa, and SRa were significantly decreased in the LAF group (all P < 0.001). In the control group, LA myocardial Ss (γ = -0.486, P < 0.01), SRs (γ = -0.436, P < 0.01), and Sa (γ = -0.360, P < 0.05) were correlated negatively with PA-TDI. LA myocardial SRa (γ = 0.377, P < 0.01) was correlated positively with PA-TDI. In the LAF group, LA myocardial Ss (γ = -0.429, P < 0.01), SRs (γ = -0.468, P < 0.01), and Sa (γ = -0.380, P < 0.05) were also correlated negatively, and SRa (γ = 0.390, P < 0.01) was correlated positively, with PA-TDI. Multivariate logistic regression identified PA-TDI as the only predictor of AF onset (OR 1.39; 95 % CI 1.02-1.54; P < 0.01). LA strain parameters were decreased and PA-TDI was prolonged in patients with LAF. Structural remodeling of the LA, assessed by 2D-STE, was correlated with electrical remodeling, determined by PA-TDI. Prolonged PA-TDI was independently associated with AF onset.

The effects of ivabradine on left atrial electromechanical function in patients with systolic heart failure

Heart rate (HR) reduction with ivabradine improves left ventricle filling by the prolongation of the diastolic time and increases stroke volume. But, it remains unclear what ivabradine's effect is on atrial conduction time and atrial mechanical functions. The aim of our study was to evaluate in stable outpatients with systolic heart failure (HF) the 3months effect of ivabradine on atrial conduction time and mechanical functions. We evaluated prospectively 43 (31 males, 12 females) patients with HF. Before and after treatment, all patients were evaluated by transthoracic M mode, two dimensional (2D), pulsed-wave (PW), continuous wave (CW), color flow and tissue Doppler imaging (TDI), and LA volumes were obtained apical four-chamber views by a disc's method. LA maximum volume (Vmax) at the end-systolic phase, LA minimum volume (Vmin) at the end-diastolic phase, and LA volume before atrial systole (Vp) were evaluated. The LA function parameters were calculated as follows: LA passive emptying volume = Vmax - Vp; LA passive emptying fraction = [(Vmax - Vp)/Vmax] × 100%, LA active emptying volume = Vp - Vmin; LA active emptying fraction = [(Vp - Vmin)/Vp] × 100%. Thirty men and 13 women with mean ± SD age of 63.9 ± 10.1years were included in this study. Resting heart rate was significantly reduced after ivabradine treatment. There were no significantly difference in LVEF, and E/A before and after ivabradine treatment. LA diameter and Vmin were similar before and after ivabradine treatment (p = 0.793 and p = 0.284). However, Vmax and Vp were significantly decreased after ivabradine treatment (p = 0.040 and p = 0.012). Moreover, LA active emptying volume and LA active emptying fraction were significantly decreased after ivabradine treatment (p = 0.030 and p = 0.008). The PA lateral, septal, and tricuspid durations were significantly reduced after ivabradine treatment (p < 0.001, p < 0.001, and p = 0.002, respectively). Interatrial electromechanical delay and right intra-atrial electromechanical delay were significantly decreased after ivabradine treatment (33.7 ± 12.7 vs 26.2 ± 10.1, p = 0.001; and 14.1 ± 6.1 vs 9.2 ± 6.8, p < 0.001). The present study demonstrated that adding ivabradine to the standard therapy reduced HR and improves significantly LA electrical and mechanical functions in systolic HF patients.

Evaluation of left atrial mechanical function and atrial conduction abnormalities in patients with isolated bicuspid aortic valve.

Present study is an evaluation of left atrial (LA) mechanical and conduction function in patients with bicuspid aortic valve (BAV) without significant valve dysfunction, and an investigation of relationship between LA function and aortic elasticity. Study population consisted of 34 isolated BAV patients (mean age: 34±13 years) and 29 healthy, age- and sex-matched volunteers (mean age: 30±10 years). LA volume was measured using biplane area-length method and LA active and passive emptying volume and fraction was calculated. Intra- and interatrial atrial conduction time (ACT) was measured with tissue Doppler imaging. Aortic elasticity parameters were calculated including aortic strain, aortic stiffness index, aortic distensibility, and aortic elastic modulus. LA diameter, LA maximum volume, LA volume before atrial systole, and LA active emptying fraction were significantly higher in patients with BAV (33.2±3.2 mm vs 34.9±2.8 mm, p=0.030; 16.2±4.6 mL/m2 vs 19.8±4.8 mL/m2, p=0.004; 10.2±3.7 mL/m2 vs 12.1±4.9 mL/m2, p=0.029; and 30.4±12.0% vs 39.9±11.8%, p=0.003, respectively). ACT was similar between groups. Aortic distensibility was significantly lower and aortic stiffness index and aortic elastic modulus were significantly higher in patients with BAV (8.1±4.6 [10-6cm2dyn-1] vs 5.1±3.6 [10-6cm2dyn-1], p=0.006; 4.1±2.8 vs 7.3±4.9, p=0.003; 3.6±2.8 [dyn.cm-2106] vs 5.9±3.9 [dyn.cm-2106], p=0.010, respectively). In correlation analysis, LA active emptying fraction was significantly correlated with aortic stiffness index and mitral A- velocity (r=0.431, p<0.001; r=0.304, p=0.016, respectively). The present study demonstrated that LA mechanical functions and aortic elasticity parameters were deteriorated, while atrial conduction time was preserved in patients with isolated BAV. Furthermore, LA mechanical functions were significantly correlated with aortic elasticity parameters and mitral inflow A-wave velocity.

A Plasma-Based, Amiodarone-Impregnated Material Decreases Susceptibility to Atrial Fibrillation in a Post-Cardiac Surgery Model.

This study aimed to test the impact of a plasma-based, material (PBM) impregnated with amiodarone on atrial electrophysiology and atrial fibrillation susceptibility in a porcine post-cardiac surgery model. Ten healthy pigs underwent implantation of transvenous pacing systems, after which sterile talc was infused into the pericardial sac via a pericardiotomy. In five animals, PBM was applied to the atrial epicardial surface just before talc infusion. Electrophysiologic evaluations were performed using the pacing system immediately after chest closure and 7 days later. Atrial histologic evaluations were performed. Immediately after chest closure, there were no significant differences in electrophysiologic parameters between talc-only and talc + PBM animals, and atrial fibrillation was largely noninducible. On postsurgical day 7, electrophysiologic evaluation revealed significantly shorter sinus cycle length and atrioventricular nodal refractoriness among talc-only animals relative to talc + PBM animals, possibly suggesting attenuated sympathetic nervous system activation in the latter. Atrial fibrillation inducibility and duration were significantly greater among talc-only animals. No significant differences in atrial refractoriness or conduction time between groups were apparent. Histologic evaluation revealed a relative reduction in epicardial inflammation and less myolysis among talc + PBM animals. Epicardial application of a plasma-based, amiodarone-impregnated material was associated with a significant reduction in atrial inflammation and susceptibility to fibrillation.

Association between hsCRP Levels, Glycemic Control and Total Interatrial Conduction Time in Patients with Type 2 Diabetes Mellitus

Background : Type 2 Diabetes Mellitus (T2DM) represents one of the most important risk factors for atrial fibrillation (AF). Numerous studies have shown that T2DM and poor glycemic control reflected by glycated hemoglobin A1c (HbA1c) levels are independently associated with new onset AF. Recent experimental studies reported that the increased susceptibility to AF in the diabetic patients was presumably due to the slowing of conduction associated with increased interstitial fibrosis. Systemic inflammation cam play role in the development of atrial fibrillation. High-sensitivity C-reactive protein (hsCRP) is an inflammatory biomarker that independently predicts the cardiovascular risk. This study aimed to determine the association between hsCRP level and glycemic control with total interatrial conduction time in T2DM patients. Subjects and Methods: This was an analytic study with cross-sectional design. A total of samples were 41 patients with T2DM. Peripheral venous blood samples to measure hsCRP and HbA1c were drawn in all study population. The total interatrial conduction time was measured by tissue Doppler echocardiography. Multivariate analysis was performed using multiple regression analysis. P < 0,050 was considered to indicate a statistically significant difference. Results : The high-sensitivity C-reactive protein level was higher in the T2DM patients with HbA1c≥7% than in the T2DM patients with HbA1c<7%, but not statistically significant (0,44±0,30 vs 0,32±0,22; p = 0,183). The total atrial conduction time was longer in the T2DM patients with HbA1c≥7% than in T2DM patients with HbA1c<7%, but not statistically significant (100,29±28,53 vs 94,88±16,50; p = 0,449). Multiple regression analysis showed that hsCRP levels and glycemic control had significant positive correlation with total interatrial conduction time in T2DM patients (r = 0,51; p = 0,004). Conclusions: The hsCRP levels and glycemic control were significant positively correlated with total interatrium conduction time in patients with type 2 diabetes. Keywords : hsCRP, glycemic control, HbA1c, total interatrial conduction time. Correspondence: Isyana Miranti K. Biomedic, Family Medicine Program, Sebelas Maret University, Surakarta. Indonesian Journal of Medicine (2016), 1(1): 58-70 https://doi.org/10.26911/theijmed.2016.01.01.08

Impact of Continuous Positive Airway Pressure Therapy on Atrial Electromechanical Delay in Obesity-Hypoventilation Syndrome Patients.

Obesity-hypoventilation syndrome (OHS) is defined as daytime hypercapnia and hypoxemia in obese patients with sleep-disordered breathing. We evaluated the electrocardiographic P-wave duration and dispersion (PD) and echocardiographic noninvasive indicators of atrial conduction heterogeneity in OHS patients and the impact of CPAP on atrial conduction and atrial fibrillation incidence. We enrolled 50 OHS patients and 50 sex- and age-matched obese subjects as control. Study population underwent cardiologic evaluation and polysomnography before enrollment, at 1- and 6-month follow-ups after CPAP therapy. The OHS group showed a significant increase in inter-atrial (35.2 ± 8 milliseconds vs. 20.1 ± 2.7 milliseconds, P < 0.0001), intra-left (30.5 ± 7.2 milliseconds vs. 16.5± 2milliseconds, P < 0.0001), and intra-right atrial electromechanical delays (AEMD)(24.8 ± 10 milliseconds vs. 15 ± 2.6 milliseconds, P < 0.0001) as well as in Pmax (130 ± 7.4 milliseconds vs. 97 ± 7.2 milliseconds, P = 0.002) and PD (56.5 ± 8.5 milliseconds vs. 31 ± 7.2 milliseconds, P = 0.002) compared to the control group. Significant improvement was noted after 6 months of CPAP therapy in inter-atrial (35.2 ± 8 milliseconds vs. 24.5 ± 6.3 milliseconds, P < 0.0001), intra-left (30.5 ± 7.2 milliseconds vs. 20.6 ± 5 milliseconds, P = 0.003), and intra-right AEMD (24.8 ± 10 milliseconds vs. 17 ± 7.5 milliseconds, P < 0.0001), as well as in Pmax (130 ± 7.4 milliseconds vs. 95 ± 10 milliseconds, P < 0.0001) and in PD (56.5 ± 8.5 milliseconds vs. 32.5± 6 milliseconds, P < 0.0001) in the OHS group. External loop recorder monitoring detected paroxysmal AF in 19 OHS patients (38%) with significant reduction in paroxysmal AF episodes (12 ± 6 vs. 47 ± 12, P < 0.0001) after 6-month CPAP therapy. Our findings showed a significant increase of electrocardiographic and echocardiographic indexes of atrial conduction heterogeneity in OHS patients. The CPAP therapy, having a positive impact on atrial conduction time, seems to reduce AF incidence in OHS patients.

Assessment of atrial conduction time in patients with systemic lupus erythematosus.

Systemic lupus erythematosus (SLE) is an autoimmune disorder resulting in multisystemic inflammatory damage. Recent articles report that 20% to 30% of deaths in patients with SLE have cardiovascular origin. The aim of this study was to investigate the atrial conduction time in patients with SLE by using high-usefulness tissue Doppler echocardiography (TDI). The study population included 56 patients with SLE (49 women; mean [SD] age, 46.2 [12.2] years, and mean [SD] disease duration, 30.7 [10.9] months) and 45 healthy subjects as control group (39 women; mean [SD] age, 45.8 [12.3] years). P-wave dispersion (PWD) was calculated by using 12-lead electrocardiogram. The timing of atrial contractions (PA) was measured as the interval between the onset of P wave on electrocardiogram and the beginning of A wave on TDI. Atrial electromechanical delay (EMD) was calculated from the lateral (PA lateral), septal (PA septal) mitral annulus, and lateral tricuspid annulus (PA tricuspid). Lateral mitral annulus and PA septal were significantly longer in the patients with SLE than in the control subjects (66.7 [15.9] vs 56.5 [13.7], P = 0.001, and 53.5 [15.0] vs 45.0 [15.1] milliseconds, P = 0.006, respectively). Interatrial (PA lateral - PA tricuspid) and intra-atrial (PA septal - PA tricuspid) EMD were significantly higher in SLE groups (25.5 [9.7] vs 19.9 [8.3], P = 0.003 and 13.3 [7.7] vs 8.4 [8.0] milliseconds, P = 0.002, respectively). Similarly, maximum P-wave duration and PWD were significantly longer in the patients with SLE than in the control subjects (104.9 [13.5] vs 98.1 [15.1], P = 0.021 and 24.6 [7.4] vs 20.0 [8.1] milliseconds, P = 0.004, respectively). There were significant positive correlations between the disease duration and interatrial EMD (r = 0.611, P < 0.001) and intra-atrial EMD (r = 0.565, P < 0.001). Positive correlation was also present between the disease duration and PWD (r = 0.457, P < 0.001). Atrial EMD is prolonged in patients with SLE. We have also shown that PWD, intra-atrial EMD, and interatrial EMD were significantly correlated with disease duration. This study calls attention to the following: the measurement of atrial conduction time may be clinically helpful in the definition of cardiac involvement.

Electrophysiological validation of total atrial conduction time measurement by tissue doppler echocardiography according to age and sex in healthy adults

BackgroundWe sought to validate total atrial conduction time (TACT) measurement via tissue Doppler imaging (TDI) by comparing the electrophysiological study (EPS) measurements of healthy subjects, according to age and sex. MethodsEighty patients with normal EPS results were included. TACT was measured by EPS and TDI. For validation, the results of TDI were compared with those of EPS. TACT was assessed by measuring the time interval between the beginning of the P-wave on the surface ECG, and the peak A-wave on TDI from the left atrial lateral wall, just over the mitral annulus. Electrophysiological TACT was defined as the time from the high right atrial electrogram to the distal coronary sinus atrial electrogram around the left lateral portion of the mitral ring. ResultsEPS and TDI measurements of the TACT were significantly and positively correlated among men and women in 20–30 years (p=0.008, r=0.412; p>0.001, r=0.706, respectively), and those in the 30–40 years group (p=0.001, r=0.649; p=0.001, r=0.696). In contrast, EPS and TDI measurements of TACT were not significantly different among men and women in the 20–30 years and those in the 30–40 years group (p>0.05, for both). On univariate regression analyses, TACT was independently associated with age (β=0.342, =0.001). ConclusionsWhen assessed according to the age and sex of healthy participants, TDI and EPS measurements during TACT assessments were similar and correlated with each other. The measurement of TACT via TDI may be used accurately and confidently than the measurement via EPS in healthy individuals.

Atrial conduction time, and left atrial mechanical and electromechanical functions in patients with polycystic ovary syndrome : interatrial conduction delay : cardiovascular topics

SummaryBackgroundPolycystic ovary syndrome (PCOS) is one of the most common endocrine disorders of women during the reproductive period. Cardiovascular risk factors are more frequent in patients with PCOS. We aimed to investigate the P-wave dispersion (Pd), inter- and intra-atrial conduction time and mechanical functions of the left atrium (LA) in patients with PCOS.MethodsForty-eight patients with PCOS and 38 normal healthy women were enrolled in this study. A 12-lead surface electrocardiogram was used to evaluate Pd. Left ventricular (LV) functions were measured using conventional and tissue Doppler imaging (TDI) methods. Inter- and intra-atrial conduction times were measured by TDI. LA volumes were measured echocardiographically with the biplane area–length method from the apical four-chamber view.ResultsHeart rate (82.02 ± 13.15 vs 74.24 ± 11.02 bpm, p = 0.014) and Pd were significantly increased in the PCOS patients [27 ± 5 vs 24 ± 6 ms, p = 0.035]. Transmitral E/A ratio was significantly lower in the PCOS patients than in the controls (1.5 ± 0.3 vs 1.7 ± 0.4 m/s, p = 0.023). Passive emptying volume (12.54 ± 4.39 vs 15.28 ± 3.85 ml/m2, p = 0.004) and passive emptying fraction [54.4 (21–69) vs 59.1% (28–74), p = 0.008] were significantly decreased in PCOS patients. Total emptying volume was significantly decreased (17.9 ± 5.49 vs 20.67 ± 4.29 ml/m2, p = 0.018) in PCOS patients. Interatrial (19 ± 7.4 vs 15 ± 6.4 ms, p = 0.035) and intra-atrial [8.5 (1–19) vs 5 ms (1–20), p = 0.026] electromechanical delays were found to be significantly higher in PCOS patients.ConclusionThis study showed that patients with PCOS had increased inter- and intra-atrial conduction delays, and decreased LA passive emptying volumes and fractions.

Predictive value of various Doppler-derived parameters of atrial conduction time for successful atrial fibrillation ablation.

Various Doppler-derived parameters of left atrial electrical remodeling have been demonstrated to predict recurrence of atrial fibrillation (AF) after AF ablation. The aim of this study was to compare three Doppler-derived measures of atrial conduction time in patients undergoing AF ablation, and to investigate their predictive value for successful procedure. In 32 prospectively enrolled patients undergoing the first AF ablation, atrial conduction time was estimated by measuring the time delay between the onset of P-wave on the surface ECG to the peak of the a′-wave on the pulsed-wave Doppler and color-coded tissue Doppler imaging of the left atrial lateral wall, and to the peak of the A-wave on the pulsed-wave Doppler of the mitral inflow. There was a significant difference in the baseline atrial conduction time measured by different echocardiographic techniques. Most (88%) patients had normal or only mildly dilated left atrium. At 6 months, 12 patients (38%) had recurrent AF/atrial tachycardia. The duration of history of AF was the only predictor of AF/atrial tachycardia recurrence following the first AF ablation (P=0.024; OR 1.023, CI 1.003–1.044). A combination of normal left atrial volume and history of paroxysmal AF of ≤48 months was associated with the best outcome. Predictive value of the Doppler derived parameters of atrial conduction time may be reduced in the early stages of left atrial remodeling. Future studies may determine which echocardiographic parameter correlates best with the extent of left atrial remodeling and is most predictive of successful AF ablation.

Preoperative tissue Doppler imaging-derived atrial conduction time predicts postoperative atrial fibrillation in patients undergoing mitral valve surgery for mitral valve regurgitation

Postoperative atrial fibrillation (POAF) is a common complication of cardiac surgery and may result in stroke, heart failure and poor prognosis.