Associations between the atrial electromechanical interval, atrial remodelling and outcome of catheter ablation in paroxysmal atrial fibrillation

Risk of atrial fibrillation development in adolescent patients with inflammatory bowel disease

There is increasing evidence linking chronic inflammation to the initiation and continuation of atrial fibrillation (AF). Inflammatory bowel diseases (IBD), namely (Crohn's disease (CD) and ulcerative colitis (UC), are chronic systemic inflammatory disorders with both intestinal and extra-intestinal manifestations. Atrial electromechanical delay (EMD) has been known as an early marker of AF. The objective of this study was to evaluate the atrial electromechanical properties in children and adolescents with IBD during remission. One hundred IBD patients aged 12-17 years (50 with CD and 50 with UC) in remission state and 100 healthy controls were recruited for the study. Atrial electromechanical properties were measured using transthoracic echocardiography, tissue Doppler imaging, and simultaneous surface ECG recording. Interatrial EMD, left intra-atrial, and right intra-atrial EMD were calculated. IBD patients in remission state have significantly prolonged left and right intra-atrial EMD and interatrial EMD compared to healthy controls (P = 0.03, P = 0.02, and P = 0.01 respectively). No statistical difference was observed between CD and UC in terms of inter- and intra-atrial EMDs.  Conclusion: Atrial EMD is increased in pediatric patients with IBD indicating the increased risk of AF development. Measurement of atrial EMD parameters might be used to predict the risk of the development of AF in pediatric patients with IBD. What is Known: • There is increasing evidence linking chronic inflammation to the initiation and continuation of atrial fibrillation (AF). • Inflammatory bowel diseases are chronic systemic inflammatory disorders with both intestinal and extra-intestinal manifestations. • Atrial electromechanical delay (EMD) has been reported as an early marker of AF. What is New: • Atrial EMD is increased in pediatric patients with IBD indicating the increased risk of AF development. • Measurement of atrial EMD parameters might be used to predict the risk of the development of AF in pediatric patients with IBD.

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

BACKGROUND

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.

METHODS

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.

RESULTS

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.

CONCLUSION

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.

Application of dynamic display technology to identify gaps after pulmonary vein isolation in catheter ablation of atrial fibrillation

BACKGROUND

The identification of post pulmonary vein isolation (PVI) gaps by activation and voltage maps is time-consuming. This study aimed to investigate the characteristics, efficiency and accuracy of LiveView dynamic display module (EnSite™ Dynamic Display; Abbott, Abbott Park, IL, USA) in unmasking post PVI gaps and conduction block line.

METHOD

Twenty four patients with paroxysmal atrial fibrillation (PAF) who failed to achieve first-pass PVI or with recurrent PAF were enrolled. Ninety-six pulmonary veins (PVs) were evaluated, and gaps were identified in 25 (26.0%) PVs. The gap location was confirmed by activation and propagation maps; 110 frames on gaps and 118 frames on block lines were analyzed by using LiveView module. We defined isochronal crowding in the local activation time (LAT) mode as three colors between two adjacent electrodes. Each frame was classified as with or without isochronal crowding in LAT mode and one/continuous color or isochronal discontinuity in reentrant mode. The gray color inside the PVs was considered to represent conduction block.

RESULT

The isochronal crowding could be found on both gap and block line in LAT mode, whereas isochronal discontinuity only presented on the block line in reentrant mode. The sensitivity and specificity of isochronal discontinuity or gray color in reentrant mode to identify block line were 61.0% and 100%, respectively. The sensitivity and specificity of isochronal crowding or gray color in LAT mode to identify block line were 71.2% and 71.8%, respectively.

CONCLUSION

Reentrant mode in LiveView module is very specific in identifying block lines. We proposed an efficient, practical algorithm to differentiate the block line from PV gaps.

Reduced atrial conduction velocity is associated with the recurrence of atrial fibrillation after catheter ablation

The recurrence of atrial fibrillation (AF) after catheter ablation (CA) is still an unsolved issue. Although structural remodeling is relatively well defined, the method to assess electrical remodeling of the atrium is not well established. In this study, we evaluated the relationship between atrial conduction properties and recurrence after CA for AF. One hundred six consecutive patients (66 ± 11 years old, male: 68%) who underwent CA for AF with a CARTO system from July 2016 to July 2019 were enrolled in this study. An activation map of both atria was constructed to precisely evaluate the total conduction time, distance, and conduction velocity between the earliest and latest activation sites during sinus rhythm. All parameters were compared between the patients with or without AF recurrence. Of the patients, 27 had an AF recurrence (Rec group). The left atrial (LA) conduction velocity was significantly slower in the Rec group than in the non-Rec group (101.2 ± 17.9 vs. 116.9 ± 18.0 cm/s, P < 0.01). Likewise, the right atrial (RA) conduction velocity was significantly slower in the Rec group than in the non-Rec group (81.1 ± 17.5 vs. 103.6 ± 25.4 cm/s, P < 0.01). A multivariate logistic analysis demonstrated that the LA and RA conduction velocities were independent predictors of AF recurrence, with adjusted odds ratios of 0.95 (95% confidential interval: 0.91-0.98, P < 0.01) and 0.94 (0.89-0.98, P < 0.01), respectively. In conclusion, slower conduction velocity of the atrium was associated with AF recurrence after pulmonary vein isolation.

Bachmann bundle impairment following linear ablation of left anterior wall: impact on left atrial function

We aimed to evaluate the effect of Bachmann bundle (BB) impairment on electrical and mechanical function of the left atrium (LA), as well as the long-term clinical impact of such impairment. We measured activation time in the five LA walls in 56 patients with atrial fibrillation. LA reservoir, conduit, and contractile function were also evaluated. Patients were divided into two groups based on ablation strategy: the circumferential pulmonary vein isolation (CPVI) group and CPVI with LA anterior wall linear ablation (LAAW) group. Patients in the CPVI + LAAW group were divided into two sub-groups based on ECG differences following ablation: the BB impairment group and intact BB group. LA activation time and function were then compared between the ablation strategy groups and the CPVI + LAAW subgroups. Patients in the CPVI + LAAW group exhibited longer activation times in the anterior and lateral walls of the LA, poorer LA synchrony, and reduced LA contractile and reservoir function when compared with those in the CPVI group. In the BB impairment subgroup, we observed a discrepancy between electrical/mechanical remodeling. Among five walls, activation time was longest in this region. BB impairment was also associated with reduced LA function. Significant changes in LA function and conductibility were observed in patients with anterior wall ablation, especially those with iatrogenic BB impairment.

Impact of stand-alone minimally invasive radiofrequency ablation with left atrial appendectomy on left atrial function assessed by echocardiography

Background

Stand-alone minimally invasive radiofrequency (RF) ablation with left atrial (LA) appendectomy has been an effective surgical intervention for non-paroxysmal atrial fibrillation (AF) (NPAF) in patients with a medical history of thromboembolism for secondary stroke prevention. This study sought to assess the impact of this surgery on LA function.

Methods

A total of 37 NPAF patients with a medical history of stroke or thromboembolism were enrolled in this prospective observational study, all of whom underwent stand-alone minimally RF ablation with LA appendectomy. Echocardiography was used to evaluate LA function preoperatively and 1 week and 3 months postoperatively. All patients were divided into two groups (Group AF and Group SR) according to whether sinus rhythm (SR) was restored after the surgery.

Results

The surgery had no impact on LA function in Group AF. Once NPAF patients were restored to SR, LA minimal volume (LAV_min) decreased immediately compared with pre-operation (22.98±13.76 vs. 17.68±9.52 mL; P<0.05) and consequently LA reservoir function increased, including LAEF (37.69%±12.53% vs. 46.71%±8.53%, P<0.05) and LAEI (66.54%±34.39% vs. 92.15%±31.37%, P<0.05). PA-TDI of Group SR, indicating LA electromechanical coupling, were improved at three months of follow-up because of atrial stunning after the surgery (160.55±26.19 vs. 143.82±20.923 ms, P<0.05). LA contractile function was also improved at three months of follow-up (A-TVI: 2.95±1.16 vs. 5.10±1.85 cm, P<0.05).

Conclusions

Stand-alone minimal invasive RF ablation with LA appendectomy had no impact on LA function in AF patients who could not be restored to SR. However, once AF patients were restored to SR after the surgery, LA function could recover better. Meanwhile, thromboembolic events could also be reduced after the surgery.

Effectiveness and safety of atrial fibrillation ablation in females

BACKGROUND

Existing data on the effectiveness and safety of atrial fibrillation (AF) ablation in females are limited to studies of small sample size, lacking longer term follow-up or adjustment for potential confounders.

METHODS

A total of 6421 patients (2072 females) undergoing a first AF ablation procedure after enrollment in the Chinese Atrial Fibrillation Registry (China-AF) study between August 2011 and December 2017 were analyzed. We evaluated the effectiveness (recurrence of documented [symptomatic or not] atrial tachyarrhythmia (AT)) and the safety (incidence of procedure-related complications) of AF ablation in female patients compared to male patients. Sensitivity analyses based on routine data were also utilized to avoid potential sex differences in reporting of AF symptoms.

RESULTS

Females were about 5 years older than males at the time of ablation (mean age 63.4 ± 9.5 vs 58.3 ± 10.8, P < .0001). A higher proportion of female patients had paroxysmal AF (74.3% vs 56.7%, P < .0001), hypertension (69.7% vs 61.3%, P < .0001), and hyperlipidemia (57.2% vs 52.9%, P = .001). Female sex was found to be an independent risk factor of AT recurrence in multivariate analyses (HR = 1.26, 95% CI 1.15-1.38, P < .0001). These findings were confirmed in sensitivity analyses using only Holter data. Female sex was also associated with a higher risk of periprocedural complications after adjustment for baseline variables (OR = 1.41, 95% CI 1.03-1.94, P = .03).

CONCLUSIONS

Female sex is an independent risk factor of AT recurrence and periprocedural complications after AF ablation.

Determinants of left intra-atrial electromechanical delay as evaluated by tissue Doppler imaging in candidates for coronary artery bypass graft surgery

OBJECTIVES

Inhomogeneity in the atrial conduction time is a predisposing factor for atrial fibrillation. The aim of our study was to determine the independent determinants of the left intra-atrial electromechanical delay (LIAEMD) as a marker of left atrial (LA) dyssynchrony in candidates for coronary artery bypass graft surgery (CABGS).

METHODS

This prospective cross-sectional study recruited 516 consecutive candidates for CABGS. Via the pulsed-wave tissue Doppler imaging modality in echocardiography, the times between the P wave and the peak of the a' wave at the septal and lateral mitral annuli were measured and the difference between these times was considered to be LIAEMD. Additionally, clinical and laboratory data on each patient were gathered. The odds ratio for an increased LIAEMD was calculated in patients with and without diabetes in univariate and multivariate analyses.

RESULTS

The multivariable analysis revealed that in the patients without diabetes, obesity, calcium-channel blocker usage, an increased maximal LA volume, and a decreased lateral e'/a' ratio and in the diabetic patients, diuretic usage and a decreased lateral e'/a' ratio were independently correlated with an increased likelihood of LIAEMD occurrence (P < .05).

CONCLUSIONS

In our study on CABGS candidates, in the patients without diabetes, obesity, an increased maximal LA volume, calcium-channel blocker usage, and a decreased lateral e'/a' ratio and in the diabetic patients, diuretic usage and a decreased lateral e'/a' ratio independently determined increased LIAEMD. The prevention or treatment of factors that are detrimental to the LA electromechanical function may be helpful for the preservation of the LA electromechanical integrity.

Left atrial structure and function predictors of recurrent fibrillation after catheter ablation: a systematic review and meta-analysis

BACKGROUND

Catheter ablation (CA) has become a conventional treatment for atrial fibrillation (AF), but remains with high recurrence rate. The aim of this meta-analysis was to determine left atrial (LA) structure and function indices that predict recurrence of AF.

METHODS

We systematically searched PubMed-Medline, EMBASE, Scopus, Google Scholar and the Cochrane Central Registry, up to September 2017 in order to select clinical trials and observational studies which reported echocardiographic predictors of AF recurrence after CA. Eighty-five articles with a total of 16 126 patients were finally included.

RESULTS

The pooled analysis showed that after a follow-up period of 21 ± 12 months, patients with AF recurrence had larger LA diameter with weighted mean difference (WMD: 2·99 ([95% CI 2·50-3·47], P<0·001), larger LA volume index (LAVI) maximal and LAVI minimal (P<0·0001 for both), larger LA area (P<0·0001), lower LA strain (P<0·0001) and lower LA total emptying fraction (LA EF) (P<0·0001) compared with those without AF recurrence. The most powerful LA predictors (in accuracy order) of AF recurrence were as follows: LA strain <19% (OR: 3·1[95% CI, -1.3-10·4], P<0·0001), followed by LA diameter ≥50 mm (OR: 2·75, [95% CI 1·66-4·56,] P<0·0001), and LAVmax >150 ml (OR: 2·25, [95% CI, 1.1-5·6], P = 0·0002).

CONCLUSIONS

Based on this meta-analysis results, a dilated left atrium with diameter more than 50 mm and volume above 150 ml or myocardial strain below 19% reflect an unstable LA that is unlikely to hold sinus rhythm after catheter ablation for atrial fibrillation.

Atrial electromechanical delay assessment in early phase after catheter ablation for patients with atrial fibrillation

BACKGROUND

Variation of atrial electromechanical delay (AED) in early phase after catheter ablation in patients with atrial fibrillation (AF) is lacking.

METHODS

Fifty-five consecutive patients restored sinus rhythm after ablation was included. Echocardiography was performed at 4 h, 1 day, and 3 days after radiofrequency catheter ablation, and AED was measured simultaneously by echocardiography with pulse Doppler imaging and pulse wave tissue Doppler imaging.

RESULTS

AED parameters were significantly longer in the nonparoxysmal atrial fibrillation (NPAF) group than in the paroxysmal atrial fibrillation (PAF) group at each checking point after ablation (P < 0.05). Compared with other checking points, AED parameters were significantly longer 4 h postablation in the NPAF group, while no significant difference was found between different checking points in the PAF group. AED-leap, representing the variation of AED in NPAF patients, was significantly positively correlated with the duration of NPAF (r = 0.5291, P = 0.0113).

CONCLUSIONS

Compared with PAF, NPAF patients have a longer AED postablation, and an abrupt decrease in the initial-h postablation. Such phenomenon gives rise to the different clinical features of PAF and NPAF, and could guide different assessment and treatment strategies for different types of AF.

Impact of a prolonged interatrial conduction time for predicting the recurrence of atrial fibrillation after circumferential pulmonary vein isolation of persistent atrial fibrillation

There are some cases that are difficult to cure with only circumferential pulmonary vein isolation (CPVI) of persistent atrial fibrillation (PerAF). Recently, prolonged interatrial conduction times (IACTs), which seem to be associated with progressive remodeled atria, have been reported as a predictor of new-onset AF. This study aimed to investigate the prognostic value of a prolonged IACT for predicting AF recurrences after CPVI of PerAF. One hundred thirteen patients who underwent CPVI without an empirical substrate modification of PerAF were retrospectively analyzed. The IACT was defined as the interval from the earliest P-wave onset on the ECG to the latest activation in the coronary sinus and was measured after achieving the CPVI and conversion to sinus rhythm. During a mean 22.7-month follow-up after the initial procedure, 56 patients (50%) had AF recurrences. Patients with AF recurrence had a longer IACT than those without AF recurrence (p < 0.001). The best discriminative cut-off value for the IACT was 123 ms (sensitivity 53%, specificity 85%). In a Cox multivariate analysis, a prolonged IACT of ≥ 123 ms was the only independent predictor (hazard ratio: 2.38; 95% confidence interval: 1.36-4.16, p = 0.002) of being associated with the incidence of an AF recurrence. Even after multiple CPVI procedures, patients with an IACT ≥ 123 ms had a higher AF recurrence rate than those with an IACT < 123 ms (p = 0.002). In conclusion, a prolonged IACT of ≥ 123 ms may be a useful marker for predicting AF recurrences after both initial and multiple CPVI procedures for PerAF.

Assessment of the atrial electromechanical properties of patients with human immunodeficiency virus

The relationship between atrial fibrillation and human immunodeficiency virus (HIV) infection was evaluated. Electro-echocardiographic methods can be used to predict the development of atrial fibrillation (AF). In this study, we aimed to investigate the atrial electromechanical delay (AEMD) parameters of HIV (+) patients. Forty-two HIV (+) patients and 40 HIV (-) healthy volunteers were prospectively enrolled in this study. The electromechanical properties of the subjects' atria were evaluated with tissue Doppler imaging. The left-AEMD, right-AEMD and inter-AEMD were increased in the HIV (+) patients relative to the controls (p=0.003, p<0.001, and p<0.001, respectively). The CD4 count was inversely correlated with the inter-AEMD (r=-0.428, p<0.001). The CD4 count was an independent predictor of the inter-AEMD (β=0.523, p=0.007). Our study demonstrated that both the inter- and intra-atrial electromechanical delays were prolonged in the patients with HIV. This non-invasive and simple technique may provide significant contributions to the assessment of the risk of atrial arrhythmia in patients with HIV.

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.

Investigation of the atrial conduction time measured by tissue Doppler imaging at the left atrial appendage and the actual electrical conduction time: consideration of left atrial remodeling in atrial fibrillation patients

PURPOSE

The atrial conduction time measured by echocardiography using tissue Doppler imaging (TDI) has been reported as a predictive factor of left atrial (LA) remodeling. We investigated the P wave to LA appendage (LAA) conduction time defined by transthoracic echocardiography using TDI (P-LAA TDI), and directly compared the actual LA electrical conduction time determined by the electrophysiological data. Additionally, we confirmed the clinical utility of the P-LAA TDI by examining the relationship to the electroanatomical LA remodeling data.

METHODS

Sixty-three AF patients (22 paroxysmal AF, 41 persistent AF) underwent ablation and electroanatomical LA mapping. The P-LAA TDI was measured after the ablation and was compared with the electrophysiological data during sinus rhythm, including the actual electrical conduction time.

RESULTS

A strong linear correlation (r = 0.776, p < 0.001, y = 1.28x + 49) was observed between the P-LAA TDI (161 ± 24 ms) and electrophysiological P-LAA time (87 ± 15 ms). The P-LAA TDI was also strongly correlated with the LA volume (173 ± 52 ml, r = 0.632, p < 0.001) and LA conduction velocity index (1.07 ± 0.19 mm/ms, r = -0.735, p < 0.001), but less to the focal anterior-LVA region surface area (2.2 [0.4-5.0] cm², r = 0.380, p = 0.002). Additionally, a stepwise multiple linear regression demonstrated that both the LA volume and LA conduction velocity index were strongly associated with the value of the P-LAA TDI (p < 0.001).

CONCLUSIONS

The P-LAA TDI was useful for estimating the actual electrophysiological conduction time and represented both electrical and anatomical LA remodeling.

Atrial Electromechanical Properties in Inflammatory Bowel Disease

BACKGROUND

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

Doppler Tissue Evaluation of Atrial Conduction Properties in Patients With Non-alcoholic Fatty-liver Disease

Non-alcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease in clinical practice, and there is an increasing trend in its prevalence in the general population. Recent studies have demonstrated increased risk of atrial fibrillation (AF) in NAFLD. However, information on the mechanism of increased risk of AF in NAFLD is lacking. Impaired atrial conduction is an important factor in the pathophysiology of AF. We aimed to investigate atrial conduction properties in patients with NAFLD by tissue Doppler echocardiography. Fifty-nine ultrasound diagnosed NAFLD patients without clinical diagnosis of hypertension, diabetes mellitus, or cardiac disease and 22 normal subjects as controls were included in this study. Atrial conduction properties were assessed by electromechanical delay (EMD) derived from Doppler tissue echocardiography examination and P-wave dispersion (PWD) calculated from the 12-lead electrocardiogram. Inter-atrial and intra-atrial EMD intervals were significantly longer in NAFLD patients than in controls (inter-atrial EMD, 31.9 ± 8.5 ms vs. 23.4 ± 4.6 ms,p= 0.0001, and intra-atrial EMD, 14.3 ± 5.2 vs. 10.2 ± 4.0 ms,p= 0.001). Similarly, PWD was significantly higher in NAFLD patients compared with controls (49.2 ± 6.3 ms vs. 43.3 ± 4.2 ms,p= 0.0001). Maximum left atrial volume was also significantly higher in the NAFLD group than in controls (51 ± 11 mL vs. 34 ± 9 mL,p< 0.0001). This study demonstrated that atrial conduction is impaired in patients with NAFLD. Also, in a patient population of NAFLD without any clinical diagnosis of cardiac disease, diabetes, or hypertension, left atrial volume was increased compared with controls. These findings suggest impaired atrial conduction as a factor in increased risk of AF in NAFLD.

The Convergent Procedure - A Standardised and Anatomic Approach Addresses the Clinical and Economic Unmet Needs of the Persistent Atrial Fibrillation Population

A standardised treatment management approach is needed to address the escalating worldwide prevalence of atrial fibrillation (AF). The persistent and longstanding persistent AF patient population particularly needs this standardised treatment option to manage their AF. These patients have underlying structural heart disease that result in increased hospitalizations, long-term medical management that increases the cost burden of the healthcare system. Approximately 100 patients have undergone the Convergent Procedure at our center since its introduction 2 years ago, as a treatment option for AF patients. The epicardial and endocardial ablation procedures performed sequentially in a single setting has shown a single procedure success rate of 80%, similar to published success rates at other centers. The epicardial posterior wall isolation silences a majority of known substrates and the endocardial procedure completes the pulmonary vein isolation, creates the cavotricuspid line and provides diagnostic confirmation. The Convergent Procedure should be considered as a first line treatment option for the persistent and longstanding persistent AF patient population who have very limited or no treatment options for the long-term successful management of their AF.

Atrial Electromechanical Properties in Coeliac Disease

BACKGROUND

Coeliac disease (CD) is an autoimmune and inflammatory disorder of the small intestine. There is reasonable evidence linking inflammation to the initiation and continuation of atrial fibrillation (AF) in inflammatory conditions. Atrial electro-mechanic delay (EMD) was suggested as an early marker of AF in previous studies. The objectives of this study were to evaluate atrial electromechanical properties measured by tissue Doppler imaging and simultaneous electrocardiography (ECG) tracing in patients with CD.

METHODS

Thirty-nine patients with coeliac disease (CD), and 26 healthy volunteers, matched for age and sex, were enrolled in the study. Atrial electromechanical properties were measured by using transthoracic echocardiography and surface ECG. Interatrial electro-mechanic delay (EMD), left intraatrial EMD, right intratrial EMD were calculated.

RESULTS

There was no difference between CD patients and healthy volunteers in terms of basal characteristics. Patients with CD had significantly prolonged left and right intraatrial EMDs, and interatrial EMD compared to healthy controls (p= 0.03, p= 0.02, p<0.0001, respectively). Interatrial EMD was positively correlated with age, disease duration, anti-gliadin IgG, anti-endomysium and disease status. In multiple linear regression, interatrial EMD was independently associated with disease duration, anti-endomysium and disease status after adjusting for age and sex.

CONCLUSIONS

In the present study, atrial EMDs were found significantly higher in patients with CD compared with healthy individuals. Measurement of atrial EMD parameters might be used to predict the risk of development of AF in patients with CD.

Comparison of Prolonged Atrial Electromechanical Delays with Different Definitions in the Discrimination of Patients with Non-Valvular Paroxysmal Atrial Fibrillation

Background and Objectives

Previous studies have evaluated atrial electromechanical delays (AEMDs) with a number of different definitions to discriminate patients with paroxysmal atrial fibrillation (PAF) from controls without PAF. However, their discriminative values for PAF have not previously been directly compared.

Subjects and Methods

A total of 65 PAF patients and 130 control subjects matched for age, sex, history of hypertension, and diabetes mellitus were selected. The AEMDi and AEMDp were defined as the time intervals from the initiation of the P wave on the surface electrocardiogram to the initiation and peak of the late diastolic transmitral inflow on pulsed wave Doppler images, respectively. The AEMDim and AEMDpm were defined as the time intervals from the initiation of the P wave on the surface electrocardiogram to the initiation and peak of the late diastolic lateral mitral annular motion on tissue Doppler images, respectively.

Results

There were no significant differences in the clinical characteristics between the two groups. All 4 AEMDs were consistently longer in the PAF group, and proven effective to differentiate the PAF patients from the controls. The AEMDi measurement had a larger area under the curve (AUC) than the other AEMDs, left atrial volume index, and P wave amplitude. However, the AEMDp, AEMDim, and AEMDpm measurements had AUCs similar to those of the left atrial volume index and P wave amplitude.

Conclusion

The findings suggest that the AEMDi is better than the other AEMDs for the discrimination of PAF patients from the controls.

Assessment of atrial conduction times in patients with mild diastolic dysfunction and normal atrial size

Objective:

Abnormalities in atrial electromechanical delays (EMDs) are considered independent predictors of atrial fibrillation and can reflect atrial remodeling. The main purpose in this study was to compare inter-left and right intra-atrial EMDs of patients with mild left ventricular (LV) diastolic dysfunction, without left atrial (LA) structural remodeling in the absence of high filling pressure, with healthy individuals.

Methods:

In this prospective study, a total of 41 consecutive outpatients who were referred to our echocardiography laboratory with mild diastolic dysfunction (age: 60.9±9.6 years) and 45 healthy control subjects who were referred from an outpatient clinic for check-up (age: 32.2±10.3 years) with normal diastolic function were enrolled into this study. All subjects had normal LA volume and normal right atrial area and did not have high filling pressure. Diastolic dysfunction were determined per American Society of Echocardiography recommendations; so, the following indices were measured: peak early (E) and atrial (A) flow velocities (cm/s), E/A ratio, and deceleration time (DT) (ms) of mitral inflow, systolic (S) and diastolic (D) pulmonary vein wave velocities (cm/s) by pulse wave Doppler, and e’ in septal and lateral mitral annulus by pulse wave tissue Doppler. Time interval from the onset of P wave on the ECG to the beginning of the late diastolic wave (Am wave) on tissue Doppler trace, which is named PA, was obtained from the lateral and septal mitral annulus and right ventricular (RV) tricuspid annulus as atrial conduction times (ACTs) and were named lateral PA, septal PA, and RV PA, respectively. The difference between lateral PA and septal, PA septal and RV PA was defined as left and right intra-atrial EMD, respectively. The difference between lateral PA and RV PA was defined as inter-atrial EMD. Data analysis was done by independent student’s t-test, Mann-Whitney U test, χ² test, Spearman rank order, Pearson’s correlation coefficient, and multivariate regression analysis in the appropriate site.

Results:

A, DT, S/D ratio, and E/e’ (average) were significantly lower in the control group, and E, D, E/A ratio, e’ septal, and e’ lateral wall were significantly lower in the patient group. Atrial conduction times were longer in the patient group, but in the multivariate analysis, there was no correlation between ACTs and diastolic dysfunction. There was no significant difference in left intra-atrial EMD (14.2±9.7 ms vs. 16.4±11.4 ms; p=0.336), right intra-atrial EMD (12.8±12.2 ms vs. 15.4±12.1 ms; p=0.321), and inter-atrial EMD (26.9±13.7 ms vs. 31.7±13.7 ms; p=0.108) between the two groups. Multivariate analysis showed no correlation between inter- and intra-atrial EMDs and diastolic dysfunction.

Conclusion:

There was no significant difference in ACTs and inter-atrial and left and right intra-atrial EMD in patients with mild LV diastolic dysfunction and normal LA volume in the absence high filling pressure compared with normal subjects.

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.

Reverse Remodelling of the Atria After Treatment of Obstructive Sleep Apnoea with Continuous Positive Airway Pressure: Evidence from Electro-mechanical and Endocrine Markers

BACKGROUND

Recent studies have suggested a strong association between obstructive sleep apnoea (OSA) and atrial fibrillation (AF). However, the impact of continuous positive airway pressure (CPAP) therapy on reverse atrial remodelling in patients with OSA is poorly understood. We aimed to determine the impact of CPAP therapy on total atrial conduction time measured by PA tissue Doppler imaging (TDI) interval in patients without history of AF.

METHODS AND RESULTS

Thirty-five patients with first diagnosed OSA (group 1) and 20 reference patients without OSA (group 2) were prospectively enrolled. Group 1 was divided into 25 patients with starting CPAP therapy (intervention group) and 10 patients without CPAP therapy (control group). PA-TDI interval, measured by tissue Doppler imaging, and B-type natriuretic-peptide (BNP) were determined at baseline and repeated after 30 days in group 1. Patients with OSA had a significantly longer PA-TDI interval (131.4±16.0 ms vs. 120.1±6.4 ms, p<0.001) compared to reference patients. PA-TDI interval shortened significantly after 30 days of CPAP therapy (131±17.1 ms vs. 124.6±15.7 ms, p<0.001), whereas no significant change was found in the control group (132.6±13.6 ms vs. 133.2±13.1 ms, p=0.31) and BNP-levels decreased significantly (39.1±50.7 pg/ml vs. 28.2±42.4 pg/ml, p<0.01), while BNP-levels remained unaffected after 30 days in control group (31.5±20 pg/ml vs. 34.4±20.5 pg/ml, p=0.41).

CONCLUSIONS

Change in PA-TDI interval, as an indirect surrogate marker of atrial remodelling, suggests reverse atrial remodelling in patients with OSA and treated by CPAP. This effect may ensue from decreased atrial pressure or volume overload, as indicated by significantly reduced BNP levels. These observations suggest that the substrate pre-disposing to AF may be reversible and moreover can be measured by PA-TDI interval and BNP.

Relationship of the total atrial conduction time to subclinical atherosclerosis, inflammation and echocardiographic parameters in patients with type 2 diabetes mellitus

OBJECTIVES

The aim of our study was to evaluate the total atrial conduction time and its relationship to subclinical atherosclerosis, inflammation and echocardiographic parameters in patients with type 2 diabetes mellitus.

METHODS

A total of 132 patients with type 2 diabetes mellitus (mean age 54.5 ± 9.6 years; 57.6% male) and 80 age- and gender-matched controls were evaluated. The total atrial conduction time was measured by tissue-Doppler imaging and the carotid intima-media thickness was measured by B-mode ultrasonography.

RESULTS

The total atrial conduction time was significantly longer in the patients with type 2 diabetes mellitus than in the control group (131.7 ± 23.6 vs. 113.1 ± 21.3, p<0.001). The patients with type 2 diabetes mellitus had significantly increased carotid intima-media thicknesses, neutrophil to lymphocyte ratios and high-sensitivity C-reactive protein levels than those of the controls. The total atrial conduction time was positively correlated with the high-sensitivity C-reactive protein level, neutrophil to lymphocyte ratio, carotid intima-media thickness and left atrial volume index and negatively correlated with the early diastolic velocity (Em), Em/late diastolic velocity (Am) ratio and global peak left atrial longitudinal strain. A multiple logistic regression analysis demonstrated that the neutrophil to lymphocyte ratio, carotid intima-media thickness and global peak left atrial longitudinal strain were independent predictors of the total atrial conduction time.

CONCLUSIONS

We suggest that subclinical atherosclerosis and inflammation may represent a mechanism related to prolonged total atrial conduction time and that prolonged total atrial conduction time and impaired left atrial myocardial deformation may be represent early subclinical cardiac involvement in patients with type 2 diabetes mellitus.

P-wave indices and atrial fibrillation: cross-cohort assessments from the Framingham Heart Study (FHS) and Atherosclerosis Risk in Communities (ARIC) study

BACKGROUND

Atrial fibrillation (AF) is associated with increased morbidity. P-wave indices (PWIs) measure atrial electrical function and are associated with AF. Study of PWI has been limited to single-cohort investigations, and their contributions to risk enhancement are unknown.

METHODS

We examined PWI from the FHS and ARIC study. We calculated 10-year AF risk using adjusted Cox models. We conducted cross-cohort meta-analyses for the PWI estimates and assessed their contributions to risk discrimination (c statistic), net reclassification index, and integrated discrimination improvement.

RESULTS

After exclusions, the analysis included 3,110 FHS (62.6 ± 9.8 years, 56.9% women) and 8,254 ARIC participants (62.3 ± 5.6 years, 57.3% women, 20.3% black race). Over 10 years, 217 FHS and 458 ARIC participants developed AF. In meta-analysis, P-wave duration >120 milliseconds was significantly associated with AF (hazard ratio 1.55, 95% CI 1.29-1.85) compared with ≤120 milliseconds. P-wave area was marginally but not significantly related to AF (hazard ratio 1.31, 95% CI 0.95-1.80). P-wave terminal force was strongly associated with AF in ARIC but not FHS. P-wave indices had a limited contribution toward predictive risk beyond traditional risk factors and markers.

CONCLUSIONS

P-wave indices are intermediate phenotypes for AF. They are associated with AF in cross-cohort meta-analyses but contribute minimally toward enhancing risk prediction.

Left atrial appendage flow velocity and time from P-wave onset to tissue Doppler-derived A' predict atrial fibrillation recurrence after radiofrequency catheter ablation

BACKGROUND

Atrial fibrillation (AF) is associated with atrial remodeling. We investigate the abilities of preprocedural echocardiographic parameters reflecting atrial remodeling to predict AF recurrence after radiofrequency catheter ablation (RFCA) for paroxysmal AF (PAF).

METHODS

Preprocedural echocardiographic parameters were measured during sinus rhythm in 105 patients with PAF undergoing RFCA. Electrical remodeling was assessed by the time from the onset of the P-wave to the peak A'-wave on the tissue Doppler imaging (PA-TDI), functional remodeling was assessed by the left atrial appendage flow velocity (LAAFV), and structural remodeling was assessed by the left atrial volume index (LAVI). PA-TDI, LAAFV, and LAVI values were divided into tertiles, and their abilities to predict AF recurrence were assessed using Cox regression analysis.

RESULTS

AF recurrence occurred in 39/105 (37.1%) patients. After adjustment for confounders, the rate of AF recurrence was significantly higher in the highest tertile of PA-TDI compared with the lowest tertile (≥151.3 msec vs. <131.0 msec; hazard ratio [HR]: 2.477, 95% confidence interval [CI]: 1.031-5.950; P = 0.042), and in the lowest tertile of LAAFV compared with the highest tertile (<48.5 cm/sec vs. ≥64.9 cm/sec; HR: 2.680, 95% CI: 1.136-6.318; P = 0.024). The risk of AF recurrence was also higher in the highest tertile of LAVI (≥34.2 mL/m(2) ) compared with the lowest tertile, but this difference was not significant (HR: 2.146, 95% CI: 0.834-5.523; P = 0.113).

CONCLUSIONS

LAAFV (reflecting functional remodeling) and PA-TDI (reflecting electrical remodeling) are independent predictors of AF recurrence after RFCA for PAF.

The association between atrium electromechanical interval and pericardial fat

OBJECTIVES

Pericardial fat (PCF) may induce local inflammation and subsequent structural remodeling of the left atrium (LA). However, the adverse effects of PCF on LA are difficult to be evaluated and quantified. The atrial electromechanical interval determined by transthoracic echocardiogram was shown to be a convenient parameter which can reflect the process of LA remodeling. The goal of the present study was to investigate the association between the electromechanical interval and PCF.

METHODS AND RESULTS

A total of 337 patients with mean age of 51.9 ± 9.0 years were enrolled. The electromechanical interval (PA-PDI) defined as the time interval from the initiation of the P wave deflection to the peak of the mitral inflow A wave on the pulse wave Doppler imaging was measured for every patient. The amount of PCF was determined by multi-detector computed tomography. The PA-PDI interval was significantly correlated with the amount of PCF (r = 0.641, p value <0.001). Graded prolongation of PA-PDI interval was observed across 3 groups of patients divided according to the tertile values of PCF. The AUC for the PA-PDI interval in predicting an increased amount of PCF (third tertile) was 0.796. At a cutoff value of 130 ms identified by the ROC curve, the sensitivity and specificity of PA-PDI interval in identifying patients with a highest tertile of PCF were 63.4% and 85.3%, respectively.

CONCLUSIONS

The PA-PDI intervals were longer in patients with an increased amount of PCF. It may be a useful parameter to represent the degree of PCF-related atrial remodeling.

Impact of metabolic syndrome on the risk of atrial fibrillation recurrence after catheter ablation: systematic review and meta-analysis

PURPOSE

The impact of metabolic syndrome (MetS) on recurrence of atrial fibrillation (AF) after catheter ablation remains uncertain. We conducted a meta-analysis to summarize the relative risks (RR) of AF recurrence after catheter ablation in patients with vs. without MetS and its components.

METHODS

Among 839 articles identified from PubMed, EMBASE, and the Cochrane Central Register of Controlled Trials, we included 23 studies with a total of 12,924 patients (7,594 with paroxysmal AF and 5,330 with nonparoxysmal AF) for analysis. Five of these had complete information on MetS components. Variables assessed comprised study design and population characteristics, AF ablation methods, use of anti-arrhythmic drugs, AF recurrence ascertainment methods, adjustment variables, and other quality indicators.

RESULTS

Our meta-analysis found an elevated risk of AF recurrence after ablation in patients with vs. without MetS (pooled RR, 1.63; 95 % confidence interval (CI), 1.25-2.12). Among components of MetS, hypertension was a predictor of AF post-ablation recurrence in studies without adjustment for other MetS components (RR, 1.62; 95 % CI, 1.23-2.13) but not in those adjusting for two or more additional MetS components (RR, 1.03; 95 % CI, 0.88-1.20). There was a borderline association between overweight/obesity and AF recurrence after ablation (RR, 1.27; 95 % CI, 0.99-1.64).

CONCLUSIONS

MetS is associated with an increased risk of AF recurrence after catheter ablation. Further study of the MetS and its components as determinants of AF risk could help refine patient selection and improve procedural outcomes.

Almanac 2013: cardiac arrhythmias and pacing

Important advances have been made in the past few years in the fields of clinical cardiac electrophysiology and pacing. Researchers and clinicians have a greater understanding of the pathophysiological mechanisms underlying atrial fibrillation (AF), which has transpired into improved methods of detection, risk stratification, and treatments. The introduction of novel oral anticoagulants has provided clinicians with alternative options in managing patients with AF at moderate to high thromboembolic risk and further data has been emerging on the use of catheter ablation for the treatment of symptomatic AF. Another area of intense research in the field of cardiac arrhythmias and pacing is in the use of cardiac resynchronisation therapy (CRT) for the treatment of patients with heart failure. Following the publication of major landmark randomised controlled trials reporting that CRT confers a survival advantage in patients with severe heart failure and improves symptoms, many subsequent studies have been performed to further refine the selection of patients for CRT and determine the clinical characteristics associated with a favourable response. The field of sudden cardiac death and implantable cardioverter defibrillators also continues to be actively researched, with important new epidemiological and clinical data emerging on improved methods for patient selection, risk stratification, and management. This review covers the major recent advances in these areas related to cardiac arrhythmias and pacing.

Atrial electromechanical interval may predict cardioembolic stroke in apparently low risk elderly patients with paroxysmal atrial fibrillation

BACKGROUND

A considerable number of patients with atrial fibrillation (AF) develop cardioembolic stroke (CE) despite low CHADS2 score. We examined the possibility that use of the atrial electromechanical interval (AEMI) improves prediction of CE in patients with paroxysmal AF (PAF), particularly those with low CHADS2 score.

METHODS

We consecutively enrolled 108 patients with nonvalvular PAF and 52 healthy subjects as controls. The PAF patients were divided into 2 groups depending on presence (n = 36) or absence (n = 72) of the history of CE. Left atrial (LA) volume index (LAVI), peak myocardial velocity during late diastole (a'), and AEMI as time from onset of P-wave to onset of lateral a' were measured.

RESULTS

Patients with PAF had significantly larger LAVI, longer AEMI, and lower lateral a' than those in controls. Area under the curves for LAVI, lateral a', and AEMI for identifying patients with PAF were 0.70, 0.69, and 0.88, respectively. Multivariate logistic regression analysis indicated that age, use of antiarrhythmic drugs, and AEMI, but not LAVI or a', were independently associated with history of CE in patients with PAF. PAF patients were categorized into low risk by CHADS2 score (i.e. CHADS2 score = 0 or 1, n = 60), those with prolonged AEMI (>82 msec) had significantly higher rates of CE than those with ≤ 82 msec (48% vs. 15%, P < 0.05).

CONCLUSION

As compared with echocardiographic parameters of LA size and LA function, AEMI appears to be more useful for identifying PAF patients. AEMI may enable to detect high risk PAF patients, especially those categorized into low risk by CHADS2 score.

Prolonged atrium electromechanical interval is associated with stroke in patients with atrial fibrillation after catheter ablation

INTRODUCTION

Atrial fibrillation (AF) is associated with increased risk of embolic stroke. Catheter ablation of AF provides an effective therapy for patients with symptomatic and drug-refractory AF. The aim of this study was to evaluate whether the atrial electromechanical interval is useful in identifying patients at risk of stroke after successful catheter ablation.

METHODS AND RESULTS

A total of 279 AF patients who received catheter ablation and showed no evidence of recurrences were enrolled. Electromechanical interval (PA-PDI) was determined as the time interval from the initiation of P wave deflection to the peak of mitral inflow A wave on pulse wave Doppler imaging. The PA-PDI interval was measured for each patient after the 3-month blanking period of catheter ablation. The clinical endpoint was the occurrence of ischemic stroke. During the follow-up of 46.5 ± 17.2 months, 6 patients suffered from ischemic strokes. Patients with strokes had higher CHA2DS2-VASc scores and longer PA-PDI intervals (138.7 ± 12.4 ms vs 161.2 ± 7.7 ms, P value < 0.001) compared to those without strokes. At a cutoff point of 150 ms identified by ROC curve, the positive and negative predictive values of the PA-PDI interval to predict stroke were 86.7% and 100%, respectively. The PA-PDI interval improved the predictive performance of the CHA2DS2-VASc score, and the area under the ROC curve increased from 0.75 to 0.85.

CONCLUSIONS

Our results suggest that the PA-PDI interval is a useful tool to identify patients with high risk of stroke after successful catheter ablation of AF.

Atrial Remodelling : Role in Atrial Fibrillation Ablation

There have been considerable advances in understanding the relationship of atrial fibrillation (AF) and atrial remodelling suggesting that remodelling states have a significant impact on treatment results. Therefore, we reviewed the literature about the role of atrial remodelling in AF treatment, focussing on AF ablation. Atrial fibrillatory activity, dominant frequencies (DF), complex fractionated atrial electrograms (CFAE) as well as function, volume, and fibrosis of the - especially left - atrium are most important characteristics for electrical, contractile, and structural remodelling predicting success of AF treatment. In particular, the results of AF ablation, either using catheter-based or surgical techniques, predominantly depend on the degree of structural remodelling, namely dilatation and fibrosis of the left atrium. The available data suggest that recognizing parameters of remodelling as predictors for AF treatment facilitates differentiation between patients who may or may not benefit from the procedure and individualization of AF treatment by adapting lesion sets, by ablating additional targets, by reducing left atrial size, or by applying extended pharmacological treatment.

The Role of Atrial Structural Remodeling in Atrial Fibrillation Ablation:An Imaging Point of View for Predicting Recurrence

Atrial fibrillation (AF) is the most common arrhythmia and is associated with a significant morbidity and mortality. Invasive catheter ablation of AF has emerged as an effective therapy for patients with symptomatic AF. Atrial remodeling, particularly structural remodeling, is important not only for AF persistence but also for AF recurrence after ablation. Atrial dilation and fibrosis are two of the core processes involved in atrial structural remodeling. Increased automaticity and triggered activity occur in atrial structural remodeling, which may cause difficulty in maintaining sinus rhythm after ablation. Furthermore, an enlarged left atrium (LA) may increase the difficulty in achieving catheter stability and thereby require more energy to complete AF ablation. AF causes similar remodeling in both the left and right atria (RA), and myocardial changes in both atria influence AF recurrence. A non-invasive assessment of fibrotic structural remodeling helps predict the outcome of AF ablation. A varie ty of cardiac imaging modalities, such as two- or three-dimensional echocardiography or multi-detector row computed tomography, have been used to estimate the magnitude of atrial structural remodeling by measuring atrial volume or LA function. Furthermore, delayed enhanced cardiac magnetic resonance imaging has been used to detect not only atrial fibrosis but also the effect of the ablation point. Thus, atrial remodeling, particularly structural remodeling, plays an important role in AF recurrence. These non-invasive imaging modalities are significant tools for estimating atrial enlargement to improve patient selection for AF ablation at the point of paroxysmal AF, and for estimating atrial fibrosis to select the AF treatment including ablation strategy at the point of development to persistent or permanent AF.

Atrium electromechanical interval in left ventricular diastolic dysfunction

BACKGROUND

  Left ventricular (LV) diastolic dysfunction has great effects on the left atrium (LA). A recently developed electromechanical interval (PA-TDI), which was determined as the time interval from the initiation of P wave deflection to the peak of local lateral LA tissue Doppler imaging signal, was reported to be associated with LA electrophysiological properties. The goal of our study was to evaluate the association between the PA-TDI interval and LV diastolic function.

MATERIALS AND METHODS

A total of 224 consecutive patients were enrolled. LV diastolic dysfunction was defined as either (i) impaired relaxation: E/A ratio < 0·75 and E/E' ratio < 10, (ii) pseudonormal pattern: 0·75 ≤ E/A ratio < 1·5 and E/E' ratio > 10 or (iii) restrictive pattern: E/A ratio ≥ 1·5 and E/E' ratio > 10. The PA-TDI intervals were measured and compared between patients with and without diastolic dysfunction.

RESULTS

  Fifty-six per cent of the study population had abnormal diastolic function. The PA-TDI interval was significantly longer in the diastolic dysfunction group than that in the normal group (147·8 ± 18·2 vs. 130·4 ± 17·0 ms, P < 0·01). In patients with diastolic dysfunction, the PA-TDI intervals became progressively longer as the diastolic dysfunction progressed from impaired relaxation (141·2 ± 11·4 ms), pseudonormal pattern (147·6 ± 18·0 ms) to restrictive pattern (164·1 ± 20·9 ms).

CONCLUSIONS

  The PA-TDI interval was significantly longer in patients with LV diastolic dysfunction than those without it. Its prolongation may reflect the severity of atrial remodelling because of the abnormal diastolic function of LV.