Role of transthoracic echocardiography in atrial fibrillation

Evaluation of Left Atrial Electromechanical Delay and Left Atrial Phasic Functions in Surgical Early Menopause Patients

BACKGROUND

This study evaluated the atrial electromechanical delay (AEMD) and the left atrial (LA) mechanical functions in patients with surgical early menopause.

METHODS

A total of 62 patients were included in the study: 33 patients with surgical early menopause and 29 age- and sex-matched healthy controls. The duration distance from the start of the P wave to the beginning of the A wave for the lateral mitral annulus, septal mitral annulus, and lateral tricuspid annulus was assessed by tissue Doppler echocardiography. The differences in these durations were used to calculate the inter- and intra-atrial mechanical delays. LA volumes were evaluated using the biplane area-length technique, and LA mechanical function values were measured.

RESULTS

The baseline laboratory and clinical characteristics were similar between the two groups. Surgical early menopause patients displayed increased static atrial electromechanical connection (PA′) times for the septal mitral annulus and lateral tricuspid annulus compared to the controls. However, the lateral mitral annulus, the inter-atrial, the intra-LA, and the right atrial EMD PA′ times were not significantly altered in surgical early menopause patients compared to controls. Importantly, the LA volume index (28.1 ± 8.17 vs. 24.89 ± 7.96 mL/m², p = 0.019), the maximal LA volume (49.6 ± 14.1 vs. 42.9 ± 16.1 mL, p = 0.004), the minimal LA volume (18.4 ± 7.0 vs. 15.2 ± 9.0 mL, p = 0.022), and the atrial precontraction LA volume (31.0 ± 10.9 vs. 24.9 ± 10.1 mL, p = 0.006) were higher in the patients with surgical early menopause compared to the controls. The LA reservoir, conduit and pumping functions and the total, passive, and active emptying volumes were all comparable between the two groups (p = 0.09; 0.06; 0.68; 0.06; 0.48; 0.07, respectively).

CONCLUSIONS

Patients with surgical early menopause demonstrated impaired atrial electrical delay and electromechanical functions.

Increased risk of atrial fibrillation in end-stage renal disease patients on dialysis: A nationwide, population-based study in Taiwan

End-stage renal disease (ESRD) patients commonly have a higher risk of developing cardiovascular diseases than general population. Chronic kidney disease is an independent risk factor for atrial fibrillation (AF); however, little is known about the AF risk among ESRD patients with various modalities of renal replacement therapy. We used the Taiwan National Health Insurance Research Database to determine the incident AF among peritoneal dialysis (PD) and hemodialysis (HD) patients in Taiwan.Our ESRD cohort include Taiwan National Health Insurance Research Database, we identified 15,947 patients, who started renal replacement therapy between January 1, 2002 and December 31, 2003. From the same data source, 47,841 controls without ESRD (3 subjects for each patient) were identified randomly and frequency matched by gender, age (±1 year), and the year of the study patient's index date for ESRD between January 1, 2002 and December 31, 2003.During the follow-up period (mean duration: 8-10 years), 3428 individuals developed the new-onset AF. The incidence rate ratios for AF were 2.07 (95% confidence interval [CI] = 1.93-2.23) and 1.78 (95% CI = 1.30-2.44) in HD and PD groups, respectively. After we adjusted for age, gender, and comorbidities, the hazard ratios for the AF risk were 1.46 (95% CI = 1.32-1.61) and 1.32 (95% CI = 1.00-1.83) in HD and PD groups, respectively. ESRD patients with a history of certain comorbidities including hypertension, diabetes mellitus, hyperlipidemia, coronary artery disease, heart failure, valvular heart disease, and chronic obstructive pulmonary disease (COPD) have significantly increased risks of AF.This nationwide, population-based study suggests that incidence of AF is increased among dialysis ESRD patients. Furthermore, we have to pay more attention in clinical practice and long-term care for those ESRD patients with a history of certain comorbidities.

The relationship between atrial electromechanical delay and left atrial mechanical function in stroke patients

OBJECTIVE

The aim of this study was to evaluate the relationship between atrial electromechanical delay (EMD) measured with tissue Doppler imaging (TDI) and left atrial (LA) mechanical functions in patients with ischemic stroke and compare them with healthy controls.

METHODS

Thirty patients with ischemic stroke were enrolled into this cross-sectional, observational study. The control group consisted of 35 age- and gender-matched apparently healthy individuals patients. Acute cerebral infarcts of probable embolic origin were diagnosed via imaging and were confirmed by a neurologist. Echocardiographically, time intervals from the beginning of P wave to beginning of A wave from the lateral and septal mitral and right ventricular tricuspid annuli in TDI were recorded. The differences between these intervals gave the mechanical delays (inter- and intra-atrial). Left atrial (LA) volumes were measured using the biplane area-length method, and LA mechanical function parameters were calculated. Statistical analysis was performed using student's t-test, chi-squared test, and Pearson's test.

RESULTS

The laboratory and clinical characteristics were similar in the two groups. Increased left atrial EMD (21.36±10.38 ms versus 11.74±6.06 ms, p<0.001), right atrial EMD (13.66±8.62 ms versus 9.66±6.81 ms, p=0.040), and interatrial EMD (35.03±9.95 ms versus 21.40±8.47 ms, p<0.001) were observed in stroke patients as compared to controls. Active LA emptying volume and fraction and passive LA emptying volumes and fraction were similar between controls and stroke patients. Total LA emptying volumes were significantly increased in stroke patients as compared to healthy controls (33.19±11.99 mL/m2 versus 27.48±7.08 mL/m2, p=0.021).

CONCLUSION

According to the results of our study, interatrial electromechanical delay may be a new predictor for ischemic stroke.

Left atrial function assessed by Doppler echocardiography rather than left atrial volume predicts recurrence in patients with paroxysmal atrial fibrillation

BACKGROUND

Paroxysmal atrial fibrillation (PaAF) may present as a single self-terminating episode of atrial fibrillation (AF) or a more persistent form after sinus conversion. We investigated predictors of recurrence in patients with PaAF.

HYPOTHESIS

Left atrial function would be an useful parameter for predicting PaAF recurrence.

METHODS

The study population included 228 PaAF patients (131 males, age 64±14 years) who underwent transthoracic echocardiography immediately after spontaneous sinus conversion at initial AF diagnosis. We followed the study patients for AF recurrence.

RESULTS

AF recurrence was demonstrated in 45 patients (20%, age 68±13 years) after spontaneous sinus conversion. Patients with recurrence had larger left atrial volume index (32±12 vs 25±10 mL/m2, P<0.001), left ventricle mass index (107±34 vs 93±25 g/m2, P=0.012), and left ventricle filling pressure (E/e'') (14±7 vs 12±5, P=0.012), whereas early diastolic mitral annular velocity (e') (5±2 vs 6±3 cm/s, P=0.021), late diastolic mitral annular velocity (A') (7±3 vs 9±2 cm/s, P<0.001), and peak systolic mitral annular velocity (7±2 vs 8±2 cm/s, P=0.045) were significantly lower. In multivariate Cox regression analysis detecting independent predictors of PaAF recurrence, lower A' (hazard ratio: 0.623, 95% confidence interval: 0.476-0.815, P=0.001) was a significant predictor of AF recurrence.

CONCLUSIONS

A', which indicates left atrial (LA) contractile function after sinus conversion, was the independent predictor of PaAF recurrence, whereas LA volume was not. LA function may be more important than LA volume in predicting recurrence particularly in patients with PaAF.

Intra-left atrial mechanical delay detected by tissue Doppler echocardiography can be a useful marker for paroxysmal atrial fibrillation

OBJECTIVES

There are some clinical and echocardiographic parameters to predict paroxysmal atrial fibrillation (PAF), but more sensitive predictors are needed. Tissue Doppler imaging may be a sensitive method for this purpose.

METHODS

Thirty-four patients with PAF and 31 control subjects were studied. Time intervals from the beginning of P-wave to beginning of A-wave from lateral and septal mitral and right ventricular tricuspid annuli in tissue Doppler imaging were recorded. The differences between these intervals gave the mechanical delays between/within the corresponding atria.

RESULTS

There were no differences between groups with regard to age. PAF patients were found to have increased left atrial dimension and intra-left atrial mechanical delay. Twenty-five milliseconds was calculated as cutoff value to predict PAF. P-wave dispersion was found to be increased in PAF.

CONCLUSIONS

This study shows an increase in intra-left atrial mechanical delay in PAF patients. This method can be used as an early marker to detect PAF.

Doppler tissue analysis of atrial electromechanical coupling in paroxysmal atrial fibrillation

The aim of this study was to: (1) evaluate atrial electromechanical coupling using M-mode Doppler tissue; and (2) test its clinical impact for detecting atrial abnormalities in paroxysmal atrial fibrillation (AF). Using Doppler tissue, the time intervals from the onset of P wave until the backward motions of the right and left atrioventricular rings in the apical 4-chamber view corresponding to the atrial contractions were measured. In paroxysmal AF group, these intervals were significantly longer than in the control group. Using the criteria that an abnormal time interval from the onset of P wave until the backward motion of the left atrioventricular ring is longer than 112 milliseconds, the sensitivity, the specificity, and the positive predictive values for paroxysmal AF are 73%, 93%, and 93%, respectively. This parameter is affected in patients with paroxysmal AF and should be useful for detecting atrial impairment related to paroxysmal AF.

How should left atrial size be reported? Comparative assessment with use of multiple echocardiographic methods

BACKGROUND

Determination of left atrial (LA) size is important in clinical decision-making. The LA anteroposterior dimension (APD) has been routinely reported as LA size assessment. Early studies indicated that the APD may have limited accuracy in quantification. Conventional 3-dimensional reconstruction (C3DR) of the LA has been validated. However, its process is time-consuming and not applicable for daily practice. To explore an accurate and practical approach, we compared different echocardiographic measurements with C3DR in 141 patients with different LA sizes.

METHODS AND RESULTS

LA size was measured with (1) the cubic equation with APD (Cub); (2) the ellipsoidal formula (Ellp); (3) biplane modified Simpson rule (biplane); and (4) simplified 3-dimensional reconstruction from 3 standard apical views with B spline interpolation (S3VR). All four methods were compared with C3DR. S3VR and biplane methods provided a close agreement to C3DR (y = 0.94x + 3.6, r = 0.95, SEE = 7.6 mL, mean difference = -1.3% for S3VR; y = 0.87x + 2.9, r = 0.91, SEE = 9.0 mL, mean difference = -9.4% for biplane). The Cub and Ellp calculations were less accurate, with significant volume underestimation (P <.001).

CONCLUSIONS

LA single dimension is not accurate for LA size measurement. Among four different methods of LA size measurement, biplane and S3VR provide the closest agreement to C3DR. The biplane, which is readily applicable with current echocardiographic equipment, should be routinely applied in clinical practice.

Atrial fibrillation in chronic dialysis patients in the United States: risk factors for hospitalization and mortality

BACKGROUND

The incidence and risk factors for hospitalized atrial fibrillation have not been previously assessed in a national population of dialysis patients.

METHODS

We analyzed the United States Renal Data System (USRDS) Dialysis Morbidity and Mortality Study (DMMS) Wave II in a historical cohort study of hospitalized atrial fibrillation. Data from 3374 patients who started dialysis in 1996 with valid follow-up times were available for analysis, censored at the time of renal transplantation and followed until November 2000. Cox Regression analysis was used to model factors associated with time to first hospitalization for atrial fibrillation (ICD9 code 427.31x) adjusted for comorbidities, demographic factors, baseline laboratory values, blood pressures, dialysis modality, and cardioprotective medications.

RESULTS

The incidence density of atrial fibrillation was 12.5/1000 person years. Factors associated with atrial fibrillation were older age (> or = 71 years vs. <48 years), extremes (both high and low) of pre-dialysis systolic blood pressure, dialysis modality (hemodialysis vs. peritoneal dialysis), and digoxin use. Baseline use of coumadin was associated with reduced mortality in patients later hospitalized for atrial fibrillation.

CONCLUSIONS

Dialysis patients had a high incidence of atrial fibrillation. This risk was largely segregated among those with established risk factors for atrial fibrillation, and hemodialysis patients. Use of coumadin was associated with improved survival among patients later hospitalized for atrial fibrillation.