Echocardiographic parameters for predicting maintenance of sinus rhythm after internal atrial defibrillation

Modified Frailty as a Novel Factor in Predicting the Maintenance of the Sinus Rhythm After Electrical Cardioversion of Atrial Fibrillation in the Elderly Population

Introduction

Frailty is a common geriatric syndrome that causes an elevated risk of catastrophic declines in the health and function among older adults – we hypothesized that frailty may be related to the maintenance of sinus rhythm after cardioversion.

Methods

The study sample was a group of 199 consecutive patients over 60 (average age 71.41 ± 6.99; 40.2% women) with AF who were hospitalized in order to perform electrical cardioversion. The Tilburg Frailty Indicator (TFI) was used to assess frailty before cardioversion. The six-month visit after the electrical cardioversion was a follow-up. The follow-up period for the maintenance of sinus rhythm after electrical cardioversion was 180 ± 14 days.

Results

Patients in whom cardioversion was effective had a statistically significantly lower severity of frailty syndrome (3.44 ± 1.83 vs 5.87 ± 1.12; p=0.000) and its components: physical components (2.14 ± 1.33 vs 3.62 ± 1.05 p=0.000); emotional components (0.92 ± 0.79 vs 1.29 ± 0.86 p=0.037) and social components (0.37 ± 0.56 vs 0.96 ± 0.46; p=0.000) compared to those patients in which cardioversion was ineffective. In the logistic regression, frailty (OR: 0.65, 95% CI:0.5010–0.8330; p=0.000) was observed to be an independent predictor for maintaining sinus rhythm.

Conclusion

Frailty is a novel, independent factor that can be used to predict the effectiveness of electrical cardioversion and the maintenance of sinus rhythm in the elderly population. Modifying the level of recognition in the Tilburg Frailty Indicator to a 4 improved the prediction of the effectiveness of electrical cardioversion as well as the maintenance of sinus rhythm.

Lack of Correlations between Electrophysiological and Anatomical-Mechanical Atrial Remodeling in Patients with Atrial Fibrillation

BACKGROUND

Atrial fibrillation (AF) progressively leads to electrical remodeling (ER) and anatomical-mechanical remodeling (AR), whose relationships in humans remain poorly known.

METHODS

ER and AR were compared in patients undergoing percutaneous radiofrequency (RF) ablation for AF. ER was defined by right and left appendage activation rates as a surrogate for atrial refractory periods. AR was approached by left atrial (LA) diameters and area and left atrial appendage (LAA) area and contractile function (mean emptying flow velocity) (LAAFV) before RF ablation. Mean duration between successive LAA contractions was considered as LAA mechanical rate.

RESULTS

Forty-one patients (31 men, age: 64 ± 9 years) with paroxysmal (27%), persistent (61%), or long-persistent AF (12%) were prospectively included (ejection fraction: 44 ± 16%). Parameters exploring AR were highly correlated to each other: LA area (28 ± 7 cm(2) ), LAA area (5.7 ± 2.25 cm(2) ), LA transverse (49 ± 7 mm), and anteroposterior diameter (59 ± 13 mm) or LAAFV (29 ± 13 cm/s; P < 0.05 for each comparison). Parameters exploring ER were also highly correlated: right atrial appendage (RAA; 181 ± 39 ms) and LAA (176 ± 33 ms) activation rates (P < 0.0001). There was no significant correlation between any ER and AR parameter. Only LAA mechanical rate (174 ± 36 ms) was correlated to LAA or RAA activations rates (P ≤ 0.01).

CONCLUSION

ER and AR are not mutually related, atrial activation rate being not correlated to LA or LAA size or function. Thus, the mechanisms leading to AF-induced atrial remodeling may differ for anatomical and electrophysiological aspects.

Transesophageal echocardiography: a complementary view of the heart

Transesophageal echocardiography has been widely used as a diagnostic tool during the past two decades to detect cardiac abnormalities that are not visible or poorly visible with transthoracic echocardiography. At present, transesophageal echocardiography is a cornerstone of modern diagnosis of several cardiac diseases, providing diagnostic, prognostic and therapeutic information. In this review, the present status of transesophageal echocardiography not only as a diagnostic tool, underlining its effects on clinical decision making, but also as a monitoring adjunct for many interventional cardiac procedures is examined.

Clinical significance of anterior mitral leaflet fibrillation in patients with nonvalvular atrial fibrillation: comparison with blood flow and wall motion of the left atrial appendage

BACKGROUND AND PURPOSE

Diastolic fibrillation of the anterior mitral leaflet (AML) is seen in patients with atrial fibrillation (AF). However, its clinical significance has been unclear. On the other hand, reduced blood flow velocity in the left atrial appendage (LAA) may be associated with LA thrombus formation. In this study, we investigate the relationship between the flow velocity and the wall motion velocity of the LAA and diastolic fibrillation of the AML in patients with nonvalvular AF.

METHODS

We performed transthoracic echocardiography (TTE) in 45 consecutive patients with chronic nonvalvular AF. The LAA flow velocity was measured by pulsed Doppler echocardiography with the sample volume positioned at the center of the LAA. The LAA wall motion velocity was measured by pulsed Doppler tissue imaging (DTI) with the sample volume at the medial wall of the LAA. The AML fibrillation velocity was measured by pulsed DTI with the sample volume at the AML tip.

RESULTS

The AML fibrillation velocity could be measured in 44 patients (97.8%), and the LAA flow and wall motion velocities were measurable in 35 (77.8%) and 42 (93.3%) patients, respectively. The AML fibrillation velocity had a range from 4 to 21 cm/s and showed significant positive correlation with the LAA flow velocity (r = 0.82, P < 0.001) and the wall motion velocity (r = 0.80, P < 0.001) of the LAA. An AML fibrillation velocity of ≤7 cm/s predicted patients having a tendency to LA thrombus formation (LAA flow velocity ≤20 cm/s) with high sensitivity (87.5%) and specificity (88.9%).

CONCLUSION

The AML fibrillation velocity seems to be a viable substitute for the LAA flow velocity in the detection of flow stagnation in the LA.

Atrial premature complexes and heart rate have prognostic significance in 1-month atrial fibrillation recurrence after electrical cardioversion

AIMS

The aim of this study was to investigate the significance of simple 24-h Holter (24H) data after electrical cardioversion (CV) for atrial fibrillation (AF) recurrence.

METHODS

We prospectively studied 47 consecutive patients subjected to CV, who successfully converted to sinus rhythm. All underwent echocardiography and 24H after CV. AF recurrence was studied at 14 days and 1 month by second 24H or by interim report of AF.

RESULTS

About 53.2% remained in sinus rhythm (group I) and the rest recurred to AF (group II). Group I had fewer atrial premature complexes per hour (APC/h) (P = 0.002) and lower maximum (max HR), average, and minimum heart rates compared with group II (all Ps < 0.05). The optimal value of APC/h and max HR with best sensitivity and specificity was 32 APC/h and 90 bpm, respectively. These findings were the predictors of AF recurrence [hazard ratio (HR) = 4.5 with 95% CI = 1.7-11.7 and HR = 4.3 with 95% CI = 1.7-10.9, respectively]. Patients with the combination of both predictors had greater HR of AF recurrence compared with those with < 32 APC/h and max HR < 90 bpm (HR = 8.8 with 95% CI = 2.5-31.4).

CONCLUSION

Patients with frequent APC/h and high max HR are at high risk for 1-month AF recurrence after electrical CV.

Electrical cardioversion for persistent atrial fibrillation or atrial flutter in clinical practice: predictors of long-term outcome

Despite the results of Atrial Fibrillation Follow-up Investigation of Rhythm Management and Rate Control versus Electrical Cardioversion for Persistent Atrial Fibrillation trials, which favour a general shift in atrial fibrillation (AF) therapeutic approach towards control of ventricular rate, a strategy based on restoration of sinus rhythm could still play a role in selected patients at lower risk of AF recurrence. We explored possible predictors of relapses after external electrical cardioversion among patients with persistent AF or atrial flutter (AFL). We analysed the clinical characteristics and conventional echocardiographic parameters of patients with persistent AF/AFL enrolled in an institutional electrical cardioversion programme. Among 242 patients (AF/AFL, 195/47; mean age 62+/-13 years), sinus rhythm was restored in 215 (89%) and maintained in 73 (34%) at a follow-up of 930 days (median). No baseline clinical/echocardiographic variables predicted acute efficacy of cardioversion at logistic regression analysis. However, two variables predicted long-term AF/AFL recurrence among patients with successful cardioversion at multivariate Cox's proportional hazards analysis: (i) duration of arrhythmia>or=1 year (HR, 2.07; 95% CI, 1.29-3.33) and (ii) presence of previous cardioversion (HR, 1.67; 95% CI, 1.17-2.38). These variables also presented high-positive predictive values (72% and 80% respectively). Whereas the high acute efficacy of electrical cardioversion (approximately 90%) does not appear to be predictable, two simple clinical variables could help identify patients at higher risk of long-term AF/AFL recurrence after successful electrical cardioversion. We think there could be a case for initially attempting external electrical cardioversion to patients who have had AF/AFL for <1 year. In such patients, the chance of long-term success appears to be relatively high.

Left atrial stiffness and its implications for cardiac function

Proper atrial function is essential for overall cardiovascular performance, mainly by its four major functions, namely, bioelectrical, hormonal, metabolic and hemodynamic. With regard to the latter, atria modulate ventricular filling by smoothing the transformation of the continuous venous return to the intermittent filling pattern of the ventricles during diastole through three main components: a phase of reservoir mainly during ventricular systole, a conduit phase during ventricular diastole and an active phase in late ventricular diastole. Although the atria assume a dynamic role in ventricular filling progression, atrial function and emptying pattern is, conversely, highly influenced by the ventricular diastolic wall stress, underlying the close connection observed between these chambers. This review focuses essentially on left atrial mechanical role, particularly on the physiological and clinical consequences of disturbed atrial compliance.

Prognostic Predictors of Sinus Rhythm Control by Amiodarone and Electrical Cardioversion in Patients Undergoing Percutaneous Transluminal Mitral Valvuloplasty for Rheumatic Atrial Fibrillation

BACKGROUND

Conversion to sinus rhythm (SR) is rarely attempted in patients with rheumatic atrial fibrillation (AF) because the length of AF duration and the dilation of left atrium (LA) make maintenance of SR difficult. In this study, predictors of the successful maintenance of SR with amiodarone and electrical cardioversion in rheumatic AF patients receiving percutaneous transluminal mitral valvuloplasty (PTMV) were identified.

METHODS AND RESULTS

This study included 23 consecutive patients undergoing PTMV for rheumatic AF (6 men, 53+/-11 years; AF duration 25 +/-24 months; LA diameter 44+/-6 mm; mitral valve area (MV) 1.1+/-0.2 cm(2)). Electrical cardioversion was required for the successful conversion to SR in all patients regardless of whether they had received amiodarone (400 mg/day) 2 months before PTMV (n=8) or 2 months after (n=15). After cardioversion, all patients received amiodarone 200 mg/day. With a follow-up period of 35+/-8 months, 14 patients (61%) remained in SR. A greater reduction in LA size (-4+/-3 mm vs 1+/-1 mm; p=0.004) and an greater increase in MV area (0.8+/-0.4 cm(2) vs 0.5+/-0.2 cm(2); p=0.01) by PTMV, not AF duration, were found to be the independent predictors for patients with successful maintenance of SR as compared with patients with recurrence of AF.

CONCLUSION

In rheumatic AF patients receiving PTMV, the successful maintenance of SR with amiodarone and electrical cardioversion can be predicted by the degree to which LA size is reduced and MV area is increased.

Clinical practicality and predictive value of transoesophageal echocardiography in early cardioversion of atrial fibrillation

AIMS

The objective of this study is to evaluate the feasibility of transoesophageal echocardiography (TOE)-guided cardioversion (CV) of atrial fibrillation (AF) in daily clinical practice.

METHODS AND RESULTS

Transthoracic echocardiography and TOE were performed in 346 consecutive patients with AF lasting longer than 48 h or of unknown duration. If no intracavitary thrombus was found, CV was performed within 24 h of the TOE examination. Anticoagulation with subcutaneous low-molecular-weight heparin and warfarin was always started before CV. Warfarin was continued for at least 1 month after CV. The predictive value of several echocardiographic parameters including peak left atrial appendage emptying velocity (PLAAEV), left ventricular ejection fraction, left atrial diameter, and spontaneous echo contrast for the initial and long-term success of CV were evaluated. Transoesophageal echocardiography revealed no thrombus or other contraindications to CV in 274/346 (79%) patients. Early CV restored normal sinus rhythm or pacemaker rhythm in 90% (246/274) of the patients. One patient (0.3%) had a stroke within 30 days after CV. Peak left atrial appendage emptying velocity was significantly lower in patients with contraindications to early CV (P<0.001). However, neither PLAAEV nor any other echocardiographic parameter predicted the initial success of CV and the maintenance of sinus rhythm during long-term follow-up.

CONCLUSION

Early TOE-guided CV with short-term anticoagulation is a safe and clinically effective alternative in treatment of AF lasting longer than 48 h or of unknown duration. The initial and long-term success of CV cannot be reliably predicted by echocardiographic parameters.

Atrial Thrombi-A Prospective Follow-up Study over 3 Years with Transesophageal Echocardiography and Cranial Magnetic Resonance Imaging

BACKGROUND

Patients with atrial fibrillation (AF) and atrial thrombi have an increased risk for cerebral embolism. However, there is little knowledge about the long-term fate of atrial thrombi and the incidence of cerebral embolism in patients under oral anticoagulation.

METHODS

Consecutive patients with persistent or permanent AF and left atrial (LA) thrombi were included in the study. We performed serial and prospective transesophageal echocardiography, cranial magnetic resonance imaging, and clinical examinations during a period of 3 years. Oral anticoagulation was continued or initiated in all patients. A target INR of 2.5 was intended in all patients.

RESULTS

Forty-three patients with LA thrombi and persistent or permanent AF were included. During the follow-up period 31(72%) of the thrombi disappeared. Patients with disappearance of thrombi had significantly smaller thrombi (P < 0.01), a lower echogenicity of thrombi (P < 0.01), and a lower LA volume (P = 0.02). Twenty-two (51%) patients suffered from cerebral embolism and/or death during the observation period. Five patients died due to embolic events. The only independent predictors of cerebral embolism were an elevated peak emptying velocity of the LA appendage (P < 0.001) and a history of previous thromboembolism (P < 0.01).

CONCLUSIONS

Patients with persistent or permanent AF and atrial thrombi have a high long-term risk of cerebral embolism and/or death (51%) even despite the oral anticoagulation therapy. Thrombus size may predict thrombus resolution under continued anticoagulation.

Prediction of the recurrence of atrial fibrillation after cardioversion in the Atrial Fibrillation Follow-up Investigation of Rhythm Management (AFFIRM) study

BACKGROUND

The early recurrence of atrial fibrillation (AF) after cardioversion and the need for frequent cardioversions to maintain sinus rhythm are important clinical features of AF management.

METHODS

We evaluated patients in the AFFIRM study whose qualifying episode of AF lasted > or = 48 hours and was terminated by cardioversion. Clinical, electrocardiographic, and echocardiographic risk factors associated with AF recurrence within 2 months of cardioversion and > or = 2 cardioversions during the first year were identified using multivariate analysis in 1293 eligible patients.

RESULTS

The risk factors for the recurrence of AF within 2 months of cardioversion were no coronary artery disease and an electrocardiographic lead II P-wave duration of > 135 milliseconds. In the subset of patients not taking antiarrhythmic drug therapy, the multivariate risk factors were no coronary artery disease, second or greater episode of AF, left ventricular ejection fraction < 0.50, and mitral valve thickening. Significant risk factors for the need for > 2 cardioversions in the first year in patients taking antiarrhythmic medication were left atrial diameter > 4.5 cm and mitral valve thickening. The overall sensitivity and specificity of these parameters for recurrence and repeated cardioversion are low.

CONCLUSION

There are several risk factors for difficulty maintaining sinus rhythm after cardioversion of persistent AF. The clinical predictive value of these factors is low, and they probably should not be used to justify withholding rhythm control efforts in patients who might benefit from sinus rhythm.

Atrial fibrillation - patients at high risk for cerebral embolism

OBJECTIVE

Patients with atrial fibrillation (AF) have a risk of cerebral embolism. Echocardiographic parameters elevate this risk significantly. However, there is little knowledge about the long-term fate and the rate of clinically silent cerebral embolism under continued oral anticoagulation. The aims of our study were to assess prognosis of patients with AF and determine a high risk group with an increased risk of cerebral embolism under oral anticoagulation.

METHODS

Consecutive patients with persistent or permanent AF and left atrial (LA) thrombi, dense spontaneous echo contrast (SEC) and/or reduced LA appendage peak emptying velocities (LAAv) were included in the study (N = 128). Patients with AF and without echocardiographic risk factors (N = 114) served as controls. All patients were examined with transesophageal echocardiography, cranial magnetic resonance imaging and clinically during a period of three years.

RESULTS

During the three-year follow-up period 6 (5%) of the high risk patients had cerebral embolism with neurological deficits. 4 (3%) patients died due to embolic events and 17 (13%) patients had silent embolism as documented on MRI. In the control group 8 (7%) patients had embolic events (n = 1 clinically apparent and n = 7 silent embolism) documented on MRI, one was clinically apparent. Study patients with an event had more commonly previous thromboembolism (p < 0.0001).

CONCLUSIONS

Patients with peristent or permanent AF and LA thrombi, dense SEC or reduced LAAv have an explicitly increased risk of cerebral embolism (21%) despite oral anticoagulation. Previous thromboembolic event is another important predictor for an event.

Atrial arrhythmias after cardiac surgery in patients with diabetes mellitus

BACKGROUND

Postoperative atrial fibrillation (AF) is a common complication of cardiac surgery and has been associated with increased incidence of other complications and increased hospital length of stay (LOS). Prevention of AF is a reasonable clinical goal, and, consequently, many randomized trials have evaluated the effectiveness of pharmacological and non-pharmacological interventions for prevention of AF. To better understand the role of various prophylactic therapies against postoperative AF, a systematic review of evidence from randomized trials was performed.

METHODS

MEDLINE search of English-language reports published between 1966 and July 2005 and a search of references of relevant papers were conducted. Clinical studies on AF after cardiac surgery were selected for this analysis. Relevant clinical information was extracted from selected articles.

RESULTS

Postoperative AF is associated with increased morbidity and mortality and longer, more expensive hospital stays. Prophylactic use of beta-adrenergic blockers reduces the incidence of postoperative AF and should be administered before and after cardiac surgery to all patients without contraindication. Prophylactic amiodarone and atrial overdrive pacing should be considered in patients at high risk for postoperative AF (for example, patients with previous AF or mitral valve surgery). For patients who develop AF after cardiac surgery, a strategy of rhythm management or rate management should be selected. For patients who are hemodynamically unstable or highly symptomatic or who have a contraindication to anticoagulation, rhythm management with electrical cardioversion, amiodarone, or both is preferred. Treatment of the remaining patients should focus on rate control because most will spontaneously revert to sinus rhythm within 6 weeks after discharge. All patients with AF persisting for more than 24 to 48 hours and without contraindication should receive anticoagulation.

CONCLUSIONS

AF frequently complicates cardiac surgery. Many cases can be prevented with appropriate prophylactic therapy. A strategy of rhythm management for symptomatic patients and rate management for all other patients usually results in reversion to sinus rhythm within 6 weeks of discharge.

Identification of good responders to rhythm control of paroxysmal and persistent atrial fibrillation by transthoracic and transesophageal echocardiography

BACKGROUND

Identification of good responders to rhythm control in the management of atrial fibrillation (AF) is worthwhile in terms of increasing hemodynamic benefit and decreasing the likelihood of unstable anticoagulation even after the Atrial Fibrillation Follow-Up Investigation of Rhythm Management.

METHODS

We tested the hypothesis that atrial substrate determines the risk of recurrence on rhythm control both in patients with paroxysmal AF (PAF) and in those with persistent or sustained AF (> or =1 week, SAF). There were 90 consecutive patients (mean age 63 +/- 12 years, 67 males and 23 females) with previous PAF (n = 66) or SAF (n = 24). They were maintained in sinus rhythm successfully for at least 1 month after conversion and then studied by transthoracic and transesophageal echocardiography. All of the patients were followed regularly by determination of symptoms, 12-lead ECG and intermittent Holter recording to determine recurrence of AF after echocardiographic study.

RESULTS

After 9.1 +/- 3.8 (range 3-12) months of follow-up, 23 of the 90 (26%) patients had documented recurrence of AF (67 without recurrence). Univariate analysis of demographic characteristics, medications, ECG and echocardiographic parameters revealed that, compared with the group of patients without recurrent AF, the group of those with it included more members of the SAF group (11/27 vs. 13/67, p = 0.039), included more male subjects (22/23 vs. 45/67, p = 0.045), had a larger left atrial volume index (LAVI; 27 +/- 9 vs. 22 +/- 9 ml/m2, p = 0.024) and had lower LA appendage peak emptying velocity (LAAPEV; 42 +/- 15 vs. 55 +/- 22 cm/s, p = 0.01). Multivariate Cox proportional hazards regression analysis adjusted for age, gender and AF group revealed that patients with LAVI <30 ml/m2 and LAAPEV >46 cm/s had the least recurrence of AF (relative risk 0.18, 95% confidence interval 0.06-0.55, vs. with LAVI >30 ml/m2 or LAAPEV <46 cm/s, p = 0.002). Kaplan-Meier probability of freedom from AF recurrence was significantly better when LAVI <30 ml/m2 (log-rank p = 0.02), LAAPEV > 46 cm/s (p = 0.013) or both (p = 0.004). The superiority to predict the rate of sinus rhythm maintenance was the same in the PAF and SAF groups.

CONCLUSIONS

Good responders to rhythm control in the PAF and SAF groups share the characteristics of smaller LA volume and better LAA contractile function, emphasizing the critical role of atrial substrate remodeling in recurrence of AF.

Patients at High Risk with Atrial Fibrillation: A Prospective and Serial Follow-up During 12 Months with Transesophageal Echocardiography and Cerebral Magnetic Resonance Imaging

OBJECTIVE

Patients with atrial fibrillation and echocardiographic risk factors have a relevant risk of cerebral embolism. However, there is little knowledge about the long-term fate and the rate of clinical silent cerebral embolism under continued oral anticoagulation. Our aims were to assess the prognosis of patients with atrial fibrillation and determine a high-risk group with an increased risk of cerebral embolism under oral anticoagulation.

METHODS

A total of 173 consecutive patients with persistent or permanent atrial fibrillation and left atrial (LA) thrombi, dense spontaneous echocontrast, reduced LA appendage peak emptying velocities, or a combination of these were included in the study. In all, 169 patients with atrial fibrillation and without echocardiographic risk factors served as control patients. We performed serial and prospective transesophageal echocardiography, cranial magnetic resonance imaging, and clinical examinations during a period of 12 months.

RESULTS

During the follow-up period 7 (4%) of the patients at high risk had cerebral embolism with neurologic deficits. A total of 4 (2%) patients died because of embolic events and 19 (11%) patients had silent embolism as documented on magnetic resonance imaging. In the control group, 10 (6%) patients had embolic events documented on magnetic resonance imaging; one was clinically apparent. Study patients with an event had more often previous thromboembolism (P < .0001).

CONCLUSIONS

Patients with persistent or permanent atrial fibrillation and LA thrombi, dense spontaneous echocontrast, or reduced LA appendage peak emptying velocities have an explicitly increased risk of cerebral embolism (17%) despite oral anticoagulation. Previous thromboembolic event is another important predictor for an event.

Incidence of Cerebral Embolism after Cardioversion of Atrial Fibrillation: A Prospective Study with Transesophageal Echocardiography and Cerebral Magnetic Resonance Imaging

BACKGROUND

After cardioversion of atrial fibrillation the risk for cerebral embolism is increased. There is little knowledge about the incidence of cerebral embolism for patients with transesophageal echocardiography (TEE)-guided cardioversion under oral anticoagulation.

METHODS

Consecutive patients with atrial fibrillation and TEE-guided cardioversion were included in the study. We performed serial TEE studies, Holter electrocardiography, cranial magnetic resonance imaging, and clinical examinations during a period of 4 weeks before and after cardioversion. Oral anticoagulation was continued or initiated in all patients.

RESULTS

During the observation period 6 of 127 (4.7%) patients had new embolic lesions after cardioversion documented on cerebral magnetic resonance imaging. Patients with an event were significantly older (P = .04) and had a larger left atrium (P = .04) than patients without event.

CONCLUSION

Patients with atrial fibrillation and oral anticoagulation have a low rate of clinical apparent cerebral embolism after TEE and anticoagulation-guided cardioversion. The rate of silent cerebral embolism is almost 5%. Age and left atrial size are predictors for an event.

Patients With Atrial Fibrillation and Dense Spontaneous Echo Contrast at High Risk

OBJECTIVES

We sought to assess the prognosis of patients with atrial fibrillation (AF) and dense spontaneous echo contrast (SEC) and to determine the incidence of cerebral embolism under continued oral anticoagulation.

BACKGROUND

Patients with AF and dense SEC have an increased risk of cerebral embolism. However, there is little knowledge about the long-term fate and the rate of clinical silent cerebral embolism under continued oral anticoagulation.

METHODS

Between 1998 and 2001, all consecutive patients with AF and dense SEC were included in the study. We performed serial and prospective transesophageal echocardiography, cranial magnetic resonance imaging, and clinical examinations during a period of 12 months.

RESULTS

A total of 128 patients with dense SEC and AF were included. The control group consisted of 143 patients with faint SEC and AF. During the follow-up period, three patients (2%) had cerebral embolism with neurologic deficits. A total of eight patients (6%) died due to embolic events, and 19 (15%) patients had silent embolism, as documented on cerebral magnetic resonance imaging. Patients with an event had significantly lower left atrial appendage peak emptying velocities and more commonly had a history of previous thromboembolism and denser SEC, as compared with patients without an event.

CONCLUSIONS

Patients with AF and dense SEC have a high likelihood of cerebral embolism (22%) and/or death, despite oral anticoagulation. Low peak emptying velocities of the left atrial appendage and dense SEC are independent predictors of an event.

Usefulness of plasma B-type natriuretic peptide in predicting recurrence of atrial fibrillation one year after external cardioversion

After successful external cardioversion, the rate of recurrence of atrial fibrillation remains high. The hypothesis that plasma B-type natriuretic peptide could predict the recurrence of atrial fibrillation at 1 year was tested. Plasma B-type natriuretic peptide was measured in 66 consecutive asymptomatic patients who underwent external cardioversion for atrial fibrillation. Twelve-lead electrocardiograms were obtained at 1 year. Sinus rhythm was maintained in 55% of patients. The independent predictors of the recurrence of atrial fibrillation at 1 year were a history of atrial fibrillation, plasma B-type natriuretic peptide, and the energy delivered for conversion. In patients without symptoms of heart failure, plasma B-type natriuretic peptide is an independent predictor of the recurrence of atrial fibrillation.

Prediction of Successful Cardioversion and Maintenance of Sinus Rhythm in Patients With Lone Atrial Fibrillation

OBJECTIVE

We aimed to prospectively investigate the predictive value of echocardiographic parameters for the prediction of successful cardioversion and long-term sinus rhythm (SR) maintenance in patients who have experienced a lone episode of atrial fibrillation (AF).

MEASUREMENTS AND RESULTS

Clinical and echocardiographic data, including mean left atrial appendage (LAA) peak flow velocity and mitral annulus motion, were analyzed in 78 consecutive patients (mean [+/- SD] age, 59.3 +/- 9.3 years) with AF lasting > 48 h and < 6 months. Sixty-one patients (78%) underwent successful external electrical cardioversion, while the remaining remained in AF. At the 1-year follow-up, of the 61 patients who had successfully been converted to SR, 24 (39.3%) remained in SR. For predicting the success of the cardioversion, we used a model consisting of two variables. LAA flow velocity (> 20 cm/s) and left ventricular (LV) fractional shortening (> 30%) appear to be quite strong, yielding 83.3% correct results. For predicting the maintenance of SR, we used a model consisting of two variables. The absence of the early systolic abnormal mitral annulus motion and LAA flow velocity (> 20 cm/s) appears to be quite strong, yielding 84.6% correct results. LAA flow velocity only marginally enters the model, and, if removed, little predictive value is lost (dropping to 83.3%). Removing the early systolic abnormal mitral annulus motion variable, the prediction value drops significantly to 70.5%.

CONCLUSION

LAA flow velocity combined with LV fractional shortening can predict the success of the conversion of AF to SR. Additionally, LAA flow velocity, combined with the analysis of mitral annulus motion before cardioversion, can predict the long-term maintenance of SR.

Fate of left atrial thrombi in patients with atrial fibrillation determined by transesophageal echocardiography and cerebral magnetic resonance imaging

Patients with atrial fibrillation (AF) and atrial thrombi have an increased risk for cerebral embolism. However, there is little knowledge about the long-term fate of atrial thrombi and the incidence of cerebral embolism in patients receiving continued oral anticoagulation. Forty-three consecutive patients with AF and atrial thrombi were enrolled in the study. Serial and prospective transesophageal echocardiographic studies, cranial magnetic resonance imaging (MRI), and clinical examinations were performed during a period of 12 months. Oral anticoagulation was continued or initiated in all patients. An international normalized ratio of 2.0 to 3.0 was regarded as effective. During follow-up, 56% of the thrombi disappeared (7 [16%] at 1 month, 18 [42%] at 3 months, 21 [49%] at 6 months, and 24 [56%] at 12 months). Patients with the disappearance of thrombi had significantly smaller thrombi compared with patients with persistent thrombi (1.5 +/- 0.8 cm in length and 0.8 +/- 0.5 cm in width vs 1.9 +/- 0.6 cm in length and 1.3 +/- 0.4 cm in width, p = 0.04), reduced echogenicity of thrombi (46% vs 89%, p <0.01), and smaller left atrial (LA) volume (83 +/- 27 vs 116 +/- 55 cm(3)). Seven patients (16%) had embolic lesions during follow-up MRI. Six of these patients (86%) had clinically apparent embolisms, and 1 died from stroke. The only independent predictors of cerebral embolism were an elevated peak emptying velocity of the LA appendage (p <0.01) and previous thromboembolic events (p = 0.02). Patients with AF and atrial thrombi have a large likelihood of cerebral embolism (16%) and/or death despite oral anticoagulation therapy. Thrombus size may predict thrombus resolution under continued anticoagulation.

P Wave Dispersion and Left Atrial Appendage Function for Predicting Recurrence after Conversion of Atrial Fibrillation and Relation of P Wave Dispersion to Appendage Function

BACKGROUND

We investigated P wave dispersion and left atrial appendage (LAA) function for predicting atrial fibrillation (AF) relapse, and the relationship between P wave dispersion and LAA function.

METHODS

Sixty-four consecutive patients with AF lasting </=3 months were evaluated to predict the recurrence after successful cardioversion. P wave duration and dispersion were measured in a 12-lead electrocardiograph (ECG). The size and function of the left atrium (LA) and LAA were assessed by transthoracic and transesophageal echocardiography.

RESULTS

After 6 months, 28 patients experienced recurrent AF and 36 remained in sinus rhythm. There was no difference between patients with and without recurrence in gender, age, underlying heart disease, AF patterns, left ventricular function, and maximum LAA area. AF duration >/=5 days, LA size >/=45 mm, maximum P wave duration >/=112 ms, P wave dispersion >/=47 ms, spontaneous echo contrast, minimum LAA area >/=166 mm(2), and LAA emptying velocity <36 cm/sec were univariate predictors of recurrence (each P < 0.05). By multivariate analysis, LA size (P = 0.02), P wave dispersion (P < 0.001), and LAA emptying flow (P = 0.01) identified patients with recurrent AF. Their positive predictive values were 91, 97, and 72%, respectively.

CONCLUSION

The increased P wave dispersion in addition to the dilated LA and the depressed LAA emptying flow can identify patients at risk of recurrent AF after cardioversion.

Echocardiographic and electrocardiographic predictors for atrial fibrillation recurrence following cardioversion

INTRODUCTION

Identification of suitable candidates for cardioversion currently is not based on individual electrical and mechanical atrial remodeling. Therefore, this study analyzed the meaning of atrial fibrillatory rate obtained from the surface ECG (as a measure of electrical remodeling) and left atrial size (as measure of mechanical remodeling) for prediction of early atrial fibrillation (AF) recurrence following cardioversion.

METHODS AND RESULTS

Forty-four consecutive patients (26 men and 18 women, mean age 62 +/- 11 years, no antiarrhythmic medication at baseline) with persistent AF were studied. Fibrillatory rate was obtained from high-gain, high-resolution surface ECG using digital signal processing (filtering, QRST subtraction, Fourier analysis) before electrical cardioversion. Univariate and multivariate regression analysis revealed larger systolic left atrial area (Beta = 0.176, P = 0.031) obtained by precardioversion echocardiogram from the apical four-chamber view and higher atrial fibrillatory rate (Beta = 0.029, P = 0.021) to be independent predictors for AF recurrence (n = 13). Stratification based on the regression equation (electromechanical index [EMI] = 0.176 systolic left atrial area + 0.029 fibrillatory rate - 17.674) allowed identification of groups at low, intermediate, or high risk. No patient with an EMI < -1.85 had early AF recurrence, as opposed to 78% with an EMI > -0.25. Intermediate results (40% recurrence rate) were obtained when the calculated EMI ranged between -1.85 and -0.25 (P < 0.001).

CONCLUSION

Fibrillatory rate obtained from the surface ECG and systolic left atrial area obtained by echocardiography may predict early AF recurrence in patients with persistent AF. These parameters might be useful in identifying candidates with a high likelihood of remaining in sinus rhythm after cardioversion.

P-wave dispersion for predicting maintenance of sinus rhythm after cardioversion of atrial fibrillation

P-wave measurements and left atrial function were investigated to predict the maintenance of sinus rhythm after cardioversion of atrial fibrillation. Left atrial dimension <45 mm (p = 0.02) and P-wave dispersion <46 ms (p <0.001) were independent predictors of sinus rhythm maintenance, with a sensitivity of 89% and 96%, respectively. Duration of atrial fibrillation, maximum P-wave duration, and no spontaneous echocardiographic contrast were also univariate predictors.

Mechanical occlusion of the left atrial appendage

INTRODUCTION

Oral anticoagulation therapy reduces significantly the risk of thromboembolism in patients with atrial fibrillation. However, effective oral anticoagulation therapy is not feasible in all patients. The interventional occlusion of the left atrial appendage may reduce the risk of thromboembolism in the latter patients. The aim of this prospective study was to assess the feasibility, safety, and technical aspects of interventionally occluding the left atrial appendage.

METHODS AND RESULTS

The left atrial appendage was interventionally occluded with the new PLAATO device in nine patients. Serial transthoracic and transesophageal echocardiographic studies and neurologic assessment were performed prior to and during the procedure, and <48 hours, 3 months, 6 months, and 1 year after the procedure. Contraindications to oral anticoagulation were bleeding complications in 6 of 9 cases, cerebral aneurysm in 1, and allergies to warfarin therapy in 2 of 9. Baseline echocardiographic studies demonstrated spontaneous echo contrast grade 3 +/- 1, peak emptying velocities of 0.26 +/- 0.12 m/sec, and excluded atrial thrombi in all cases. Interventional occlusion was feasible in all cases. One patient had a minor plexus paresis that resolved within 4 weeks after the procedure. Neurologic assessment during a mean follow-up of 5 +/- 4.4 months did not demonstrate any new neurologic complications. Serial echocardiographic assessment excluded the formation of thrombi on the implanted device and demonstrated its complete thrombosis after 6 months. One patient developed a minimal pericardial effusion 48 hours after the procedure that resolved within 3 months.

CONCLUSION

Interventional occlusion of the left atrial appendage is feasible and safe in patients with atrial fibrillation and contraindications to oral anticoagulation therapy. Furthermore, no neurologic complications, development of atrial thrombi, or thrombus formation on the device were observed during follow-up. Future prospective studies are needed to clarify the long-term treatment effect of this new technique.

Survey of observer variation in transesophageal echocardiography: comparison of anesthesiology and cardiology literature

OBJECTIVE

Transesophageal echocardiographic examination tends to be somewhat observer and experience dependent, and observer bias can arise easily when data are calculated and interpreted by unskilled, nonblinded, or single observers. The study plan was to see whether authors have adequately described how observer bias is minimized in their studies. Thus, a study was conducted systematically reviewing methods reported in transesophageal echocardio graphy articles in peer-reviewed anesthesiology journals versus those reported in peer-reviewed cardiology journals.

INTERVENTIONS

After MEDLINE searches of the literature published from 1997 through 1999, the authors investigated 56 anesthesiology reports and 56 randomly selected, year-matched cardiology reports. An 8-item questionnaire was developed that examined several factors: the number of observers and their experience levels, whether observers were blind to clinical data, whether low-quality images were excluded, the use of on-line or off-line analysis, and observer variability.

MAIN RESULTS

The analysis revealed inadequacies in reporting of important information that relates to bias and quality in 91.1% of anesthesiology and 98.2% of cardiology articles. Observer variability was not reported in 50.0% of the anesthesiology reports and 67.9% of the cardiology reports; however, difference between the 2 bodies of literature was not significant. The journal impact factor was significantly higher for the cardiology literature than for the anesthesiology literature (2.42 [0.386-10.893] v 1.07 [0.664-3.439]; median [range], p < 0.001).

CONCLUSION

Articles reviewed had at least some inadequacies in reporting the methods to minimize observer bias in both the anesthesiology and cardiology literature. Reporting methodology standards in TEE examinations remain to be established.

Silent and apparent cerebral embolism after retrograde catheterisation of the aortic valve in valvular stenosis: a prospective, randomised study

BACKGROUND

In most patients, severity of valvular aortic stenosis can be accurately assessed non-invasively by echocardiography. However, retrograde catheterisation of the aortic valve is often undertaken. This procedure has a potential risk of neurological complications, with an unknown incidence of clinically silent embolism. We aimed to establish the frequency of clinically apparent and silent cerebral embolism after this procedure.

METHODS

We prospectively randomised 152 consecutive patients with valvular aortic stenosis at a German university hospital to receive either cardiac catheterisation with (n=101) or without (n=51) passage through the aortic valve. Patients underwent cranial MRI and neurological assessment within 48 h before and after the procedure to assess cerebral embolism. Controls were 32 patients without valvular aortic stenosis who underwent coronary angiography and laevocardiography.

FINDINGS

22 of 101 patients (22%) who underwent retrograde catheterisation of the aortic valve had focal diffusion-imaging abnormalities in a pattern consistent with acute cerebral embolic events after the procedure; three of these patients (3%) had clinically apparent neurological deficits. By contrast, none of the patients without passage of the valve, or any of the controls, had evidence of cerebral embolism as assessed by MRI.

INTERPRETATION

Patients with valvular aortic stenosis who undergo retrograde catheterisation of the aortic valve have a substantial risk of clinically apparent cerebral embolism, and frequently have silent ischaemic brain lesions. Patients should be informed about these risks, and this procedure should be used only in patients with unclear echocardiographical findings when additional information is necessary for clinical management.

Clinical value of left atrial appendage flow for prediction of long-term sinus rhythm maintenance in patients with nonvalvular atrial fibrillation

OBJECTIVES

This study evaluated the role of various clinical and echocardiographic parameters, including the left atrial appendage (LAA) anterograde flow velocity, for prediction of the long-term preservation of sinus rhythm (SR) in patients with successful cardioversion (CV) of nonvalvular atrial fibrillation (AF).

BACKGROUND

Echocardiographic parameters for assessing long-term SR maintenance after successful CV of nonvalvular AF are not accurately defined.

METHODS

Clinical, transthoracic echocardiographic and transesophageal echocardiographic (TEE) data--measured in AF lasting >48 h--of 186 consecutive patients (116 men, mean age: 65 +/- 9 years) with successful CV (electrical or pharmacologic) were analyzed for assessment of one-year maintenance of SR.

RESULTS

At one-year follow-up, 91 of 186 (49%) patients who underwent successful CV continued to have SR. Mean LAA peak emptying flow velocity was higher in patients remaining in SR for one year than in those with AF relapse (41.7 +/- 20.2 cm/s vs. 27.7 +/- 17.0 cm/s; p < 0.001). On multivariate logistic regression analysis, only the mean LAA peak emptying velocity >40 cm/s (p = 0.0001; chi(2): 23.9, odds ratio [OR] = 5.2, confidence interval [CI] 95% = 2.7 to 10.1) and the use of preventive antiarrhythmic drug treatment (p = 0.0398; chi(2): 4.2; OR = 2.0, CI 95% = 1.0 to 3.8) predicted the continuous preservation of SR during one year, outperforming other univariate predictors such as absence of left atrial spontaneous echocardiographic contrast during TEE, the left atrial parasternal diameter <44 mm, left ventricular ejection fraction >46% and AF duration <1 week before CV. The negative and positive predictive values of the mean LAA peak emptying velocity >40 cm/s for assessing preservation of SR were 66% (CI 95% = 56.9 to 74.2) and 73% (CI 95% = 62.4 to 83.3), respectively.

CONCLUSIONS

In TEE-guided management of nonvalvular AF, high LAA flow velocity identifies patients with greater likelihood to remain in SR for one year after successful CV. Low LAA velocity is of limited value in identifying patients who will relapse into AF.

Antiarrhythmic agents in facilitating electrical cardioversion of atrial fibrillation and promoting maintenance of sinus rhythm

Atrial fibrillation (AF) is a prevalent arrhythmia associated with significant morbidity and mortality. Electrical cardioversion of AF is a potentially definitive treatment, but as little as 67% of patients may be successfully cardioverted and, after normal sinus rhythm (NSR) is achieved, AF often recurs. Class IA, IC, and III antiarrhytmic agents are used for both facilitation of electrical cardioversion and subsequent maintenance of NSR. The mechanisms of these agents may be related to suppressing automaticity, prolonging the wavelength of reentrant wavelets, and preventing electrical remodeling. The possibility of proarrhythmia and other adverse effects complicates use of these drugs, and no large trials have been completed to elucidate definite indications. Several factors may predict failure with electrical cardioversion alone (duration of AF, atrial size, age, underlying disease, and factors that affect transthoracic impedance), calling for empiric pharmacotherapy to facilitate cardioversion. For this purpose, class IA agents hold some promise, evidence for class IC agents is conflicting, and class III agents are the most effective. Adverse effects are rare given the short course before cardioversion, but ibutilide, the most efficacious in this regard, may be proarrhythmic after only a single dose. In promoting maintenance of sinus rhythm, antiarrhythmics across the different classes have similar efficacies: NSR may be maintained in approximately 40-65% of patients compared to approximately 30-35% with placebo at 1 year. Amiodarone is distinct in its success, with approximately 60-80% of patients remaining in NSR. For all of these agents, long-term therapy may lead to proarrhythmia or other substantial adverse effects. Finally, a serial antiarrhythmic strategy may be effective, with maintenance of NSR and minimal adverse effects ultimately achieved by trial and error.

Prevalence of left atrial chamber and appendage thrombi in patients with atrial flutter and its clinical significance

OBJECTIVES

The study was done to assess the prevalence of left atrial (LA) chamber and appendage thrombi in patients with atrial flutter (AFl) scheduled for electrophysiologic study (EPS), to evaluate the prevalence of thromboembolic complications after transesophageal echocardiographic (TEE)-guided restoration of sinus rhythm and to evaluate clinical risk factors for a thrombogenic milieu.

BACKGROUND

Recent studies showed controversial results on the prevalence of atrial thrombi and the risk of thromboembolism after restoring sinus rhythm in patients with AFl.

METHODS

Between 1995 and 1999, patients with AFl who were scheduled for EPS were included in the study. After transesophageal assessment of the left atrial appendage and exclusion of thrombi, an effective anticoagulation was initiated and patients underwent EPS within 24 h.

RESULTS

We performed 202 EPSs (radiofrequency catheter ablation, n = 122; overdrive stimulation, n = 64; electrical cardioversion, n = 16) in 139 consecutive patients with AFl. Fifteen patients with a thrombogenic milieu were identified. All of them had paroxysmal atrial fibrillation (AF). Transesophageal echocardiography revealed LA thrombi in two cases (1%). After EPS no thromboembolic complications were observed. Diabetes mellitus, arterial hypertension and a decreased left ventricular ejection fraction were found to be independent risk factors associated with a thrombogenic milieu.

CONCLUSIONS

The findings of a low prevalence of LA appendage thrombi (1%) in patients with AFl and a close correlation between a history of previous embolism and paroxysmal AF support the current guidelines that patients with pure AFl do not require anticoagulation therapy, whereas patients with AFl and paroxysmal AF should receive anticoagulation therapy. In addition, the presence of clinical risk factors should alert the physician to an increased likelihood for a thrombogenic milieu.

Left atrial appendage outflow velocity index is superior to conventional criteria for prediction of maintenance of sinus rhythm after cardioversion. An echocardiographic study in patients with atrial fibrillation of a few months' duration

OBJECTIVE

To investigate whether left atrial appendage outflow velocity alone or in relation to left atrial diameter is a superior predictor of sinus rhythm maintenance after cardioversion compared with traditional clinical or echocardiography parameters.

DESIGN

Sixty-two patients with their first episode of atrial fibrillation were examined using echocardiography before DC-cardioversion. At one month's follow-up, 42 patients had maintained sinus rhythm (group A), and 20 had relapsed into atrial fibrillation (group B). There were no differences in arrhythmia duration or antiarrhythmic therapy between the groups.

RESULTS

Left atrial diameter measured by echocardiography was smaller in group A (42 mm, 95% CI 40.9-44.1 mm) compared with group B (46 mm, 95% CI 43.4-48.2, p < 0.05). Patients in group A had a higher left atrial appendage outflow velocity at 0.44 m/s (95% CI 0.39-0.49) compared with 0.34 m/s (95% CI 0.30-0.37) in group B (p < 0.01). The ratio of left atrial appendage flow to left atrial diameter was 0.011 (95% CI 0.009-0.012) in group A compared with 0.008 (95% CI 0.007-0.009) in group B, and 63% (95% CI 33-78) of the patients in group A had velocity ratio >0.009 compared with 20% (95% CI 2-38) in group B, (p < 0.01). Stepwise multiple logistic regression analysis showed that a velocity ratio >0.009 was the only predictor for maintenance of sinus rhythm one month after cardioversion with an odds ratio of 6.4 (95% CI 1.9-23.8), (p = 0.004).

CONCLUSION

The ratio of left atrial appendage outflow velocity to left atrial diameter is superior to the traditionally used criteria for prediction of maintenance of sinus rhythm following DC-conversion of first-episode atrial fibrillation.

Role of transesophageal echocardiography-guided cardioversion of patients with atrial fibrillation

Electrical cardioversion of patients with atrial fibrillation (AF) is frequently performed to relieve symptoms and improve cardiac performance. Patients undergoing cardioversion are treated conventionally with therapeutic anticoagulation for three weeks before and four weeks after cardioversion to decrease the risk of thromboembolism. A transesophageal echocardiography (TEE)-guided strategy has been proposed as an alternative that may lower stroke and bleeding events. Patients without atrial cavity thrombus or atrial appendage thrombus by TEE are cardioverted on achievement of therapeutic anticoagulation, whereas cardioversion is delayed in higher risk patients with thrombus. The aim of this review is to discuss the issues and controversies associated with the management of patients with AF undergoing cardioversion. We provide an overview of the TEE-guided and conventional anticoagulation strategies in light of the recently completed Assessment of Cardioversion Using Transesophageal Echocardiography (ACUTE) clinical trial. The two management strategies comparably lower the patient's embolic risk when the guidelines are properly followed. The TEE-guided strategy with shorter term anticoagulation may lower the incidence of bleeding complications and safely expedite early cardioversion. The inherent advantages and disadvantages of both strategies are presented. The TEE-guided approach with short-term anticoagulation is considered to be a safe and clinically effective alternative to the conventional approach, and it is advocated in patients in whom earlier cardioversion would be clinically beneficial.

Left atrial appendage flow in nonrheumatic atrial fibrillation : relationship with pulmonary venous flow and ECG fibrillatory wave amplitude

OBJECTIVE

This study was conducted (1) to examine the relationship between left atrial appendage (LAA) flow velocity and pulmonary venous flow (PVF) variables during nonrheumatic atrial fibrillation (AF), and (2) to determine whether a reduction in LAA flow is reflected by the fibrillatory wave amplitude on the surface ECG.

BACKGROUND

Although LAA Doppler echocardiographic signals provide information regarding the velocity and direction of flow only for a localized narrow sample, systolic PVF represents in part the global left atrial function, mainly relaxation. Controversy exists about whether the amplitude of fibrillatory waves recorded on the surface ECG correlates with LAA flow velocity during AF.

MEASUREMENTS AND RESULTS

Thirty-three patients (20 men, 13 women; mean [+/- SD] age, 61 +/- 11 years) with nonrheumatic AF undergoing transthoracic and transesophageal echocardiography were studied. A correlation between LAA flow velocity and systolic PVF variables (peak systolic velocity, R: = 0.450, p = 0.009; velocity-time integral of systolic flow, R = 0.491, p = 0.004; systolic fraction of PVF, R: = 0.627, p < 0.0001) was observed. Patients with a low LAA flow profile (< 25 cm/s) had a reduced systolic PVF. Longer AF duration and the occurrence of moderate mitral regurgitation were related to reduced LAA flow. AF was subdivided into coarse (peak-to-peak fibrillatory amplitude > or = 1 mm) or fine (< 1 mm) in standard ECG lead V1. There was no association between the coarseness of AF and the LAA flow profile.

CONCLUSION

In patients with nonrheumatic AF, a reduction in LAA flow velocity correlates with a reduction in systolic PVF. These hemodynamic changes are not reflected by the ECG fibrillatory wave amplitude.

Transesophageal echocardiography (TEE) in atrial fibrillation

Transesophageal echocardiography has given new insight into the pathogenesis of the thromboembolic sequelae of AF and expanded the available therapeutic options. Studies to date indicate that TEE-guided cardioversion is a safe and reasonable approach when the clinical situation warrants prompt restoration of sinus rhythm. Whether widespread use of this strategy offers further benefit remains to be established, although there are theoretical advantages to such an approach. The potential for earlier cardioversion using a TEE-guided approach may facilitate the achievement and maintenance of sinus rhythm. In the long term, earlier restoration of sinus rhythm prevents adverse atrial remodeling, lowers embolic risk, and may improve cardiac performance and functional status. Thromboembolic sequelae (either cardioversion-related or as a result of chronic AF) remain the most devastating complications of AF. Every attempt to minimize this risk should be pursued aggressively. Information gathered from TEE has helped to elucidate the mechanisms responsible for postcardioversion embolism and has emphasized the importance of anticoagulation during and after the restoration of sinus rhythm. TEE also has the potential to further risk stratify patients with AF. Ultimately, a subset of patients may be identified who require more intense anticoagulation (i.e., those with dense SEC or thrombus, or persistent thrombus after prolonged anticoagulation) or in whom cardioversion may be deferred entirely. Likewise, TEE also may prove to be useful in identifying patients with a low-clinical risk profile who may be treated with aspirin alone and patients in whom warfarin may be superior. The results of the ACUTE study should help to further define the role of TEE in the management of patients with AF. Additional clinical studies are needed to address some of the issues that have been raised and to allow for optimal use of TEE in this patient population.

Plasma cardiac natriuretic peptides as biochemical markers of recurrence of atrial fibrillation in patients with mild congestive heart failure

To determine changes in plasma brain natriuretic peptide (BNP) after direct current cardioversion (DC) and to evaluate the relationship between plasma atrial natriuretic peptide (ANP) and BNP and the recurrence of atrial fibrillation (AF) after DC in patients with mild congestive heart failure (CHF), plasma ANP and BNP were measured before and after DC in 71 patients with mild CHF and then followed. In 65 patients with successful DC, both ANP and BNP decreased 15 min after DC. Cox stepwise multivariate analysis among 14 variables such as age, history of AF, echocardiographic parameters, medication and ANP and BNP revealed that only low ANP (p=0.005) and high BNP before DC (p=0.0002) were independent predictors of recurrent AF. A ratio of ANP to BNP less than 0.44 was a significant risk factor for AF recurrence by Kaplan-Meier analysis (p=0.02). BNP began to decrease immediately after successful DC. High BNP and relatively low ANP compared with BNP were independent risk factors of AF recurrence in patients with mild CHF.

Hemodynamic and cardiorespiratory function following internal atrial defibrillation for chronic atrial fibrillation

Internal atrial defibrillation (IAD) is able to restore sinus rhythm in patients with chronic atrial fibrillation (AF) and failed external electrical and/or pharmacologic cardioversion. To assess whether cardiorespiratory and hemodynamic function improve after IAD, 35 patients were prospectively investigated during constant workload exercise by spiroergometry and Doppler echocardiography before IAD, and 1 day and 1 month after IAD. Oxygen uptake kinetics, ventilation, left atrial mechanical function, and pulmonary artery pressure were determined simultaneously at rest and during steady state. During the serial follow-up, 20 patients maintained sinus rhythm. The time interval for achieving the steady state (146 +/- 53 vs 132 +/- 42 seconds; p = 0.5) and the oxygen deficit (645 +/- 190 vs 670 +/- 174 ml; p = 0.7) were not different before and 1 day after IAD, but decreased significantly after 1 month (98 +/- 16 seconds, p = 0.01 and 487 +/- 72 ml, p = 0.02). Exercise pulmonary artery systolic pressures were 38 +/- 13 mm Hg before IAD, increased significantly to 46 +/- 11 mm Hg on day 1 (p = 0.03), and decreased below baseline values at 1 month to 31 +/- 12 mm Hg (p = 0.07). Peak A-wave velocities increased from 0.51 +/- 0.1 m/s after 1 day to 0.67 +/- 0.2 m/s after 1 month (p = 0.03). Restoration of sinus rhythm in patients with AF resistant to external electrical and/or pharmacologic cardioversion improves hemodynamic and cardiorespiratory function at daily activity exercise levels.