Impact of body mass index on diastolic function in patients with normal left ventricular ejection fraction.

BACKGROUND: Obesity is a major public health epidemic and is associated with increased risk of heart failure and mortality. We evaluated the impact of body mass index (BMI) on the prevalence of diastolic dysfunction (DD). METHODS: We reviewed clinical records and echocardiogram of patients with baseline echocardiogram between 1996 and 2005 that showed normal left ventricular ejection fraction (LVEF). Diastolic function was labeled as normal, stage 1, stage 2 or stage 3/4 dysfunction. Patients were categorized as normal weight (BMI <25 kg m(-2)), overweight (25-29.9 kg m(-2)), obese (30-39.9 kg m(-2)) and morbidly obese (40 kg m(-2)). Multivariable ordinal and ordinary logistic regression were performed to identify factors associated with DD, and evaluate the independent relationship of BMI with DD. RESULTS: The cohort included 21 666 patients (mean (s.d.) age, 57.1 (15.1); 55.5% female). There were 7352 (33.9%) overweight, 5995 (27.6%) obese and 1616 (7.4%) morbidly obese patients. Abnormal diastolic function was present in 13 414 (61.9%) patients, with stage 1 being the most common. As BMI increased, the prevalence of normal diastolic function decreased (P<0.0001). Furthermore, there were 1733 patients with age <35 years; 460 (26.5%) and 407 (23.5%) were overweight and obese, respectively, and had higher prevalence of DD (P<0.001). Using multivariable logistic regression, BMI remained significant in both ordinal (all stages of diastolic function) and binary (normal versus abnormal). Also, obesity was associated with increased odds of DD in all patients and those aged <35 years. CONCLUSIONS: In patients with normal LVEF, higher BMI was independently associated with worsening DD.

Longitudinal rotation: an unrecognised motion pattern in patients with dilated cardiomyopathy.

BACKGROUND: Heart failure patients who are candidates for CRT frequently display longitudinal rotation (LR) - a swinging motion of the heart when imaged in a horizontal long-axis plane. OBJECTIVES: To identify the magnitude and predictors of LR in patients with ischaemic (ICM) and idiopathic dilated (DCM) cardiomyopathy, and to assess predictive value of LR in patients undergoing cardiac resynchronisation therapy (CRT). DESIGN AND SETTING: A retrospective study in a tertiary heart care setting. METHODS: Echocardiography was performed in 45 ICM and 41 DCM patients who were CRT candidates and 16 control subjects. Global LR, segmental strains and segmental LR were assessed from echocardiograms using speckle tracking. Repeat echocardiography >40 days after the beginning of CRT was performed in 64 patients. RESULTS: While DCM patients with QRS duration of both <130 ms and > or =130 ms displayed significant clockwise LR (p<0.001 for both vs 0), ICM patients and control subjects had LR that did not differ from 0. The most significant LR predictor was end-diastolic volume (p<0.001) followed by the absence of ischaemia (p<0.001) and QRS duration (p = 0.05). DCM patients with prominent clockwise LR had lower septal but higher lateral strains than DCM patients with minimal LR, or ICM patients with counterclockwise LR. LR correlated with decrease of end-systolic volume in DCM (r = 0.49, p = 0.004), while no relationship was observed in ICM. CONCLUSION: Clockwise LR is linked to presence of DCM, with the small impact of QRS duration. LR is a moderately strong predictor of end-systolic volume decrease during CRT in DCM.

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.

Selective AV nodal vagal stimulation improves hemodynamics during acute atrial fibrillation in dogs.

Although the atrioventricular node (AVN) plays a vital role in blocking many of the atrial impulses from reaching the ventricles during atrial fibrillation (AF), a rapid irregular ventricular rate nevertheless persists. The goals of the present study were to explore the feasibility of novel epicardial selective vagal nerve stimulation for slowing of the ventricular rate during AF and to characterize the hemodynamic benefits in vivo. Electrophysiological-echocardiographic experiments were performed on 11 anesthetized open-chest dogs. Hemodynamic measurements were performed during three distinct periods: 1) sinus rate, 2) AF, and 3) AF with vagal nerve stimulation. AF was associated with significant deterioration of all measured parameters (P < 0.025). The vagal nerve stimulation produced slowing of the ventricular rate, significant reversal of the pressure and contractile indexes (P < 0.025), and a sharp reduction in one-half of the abortive ventricular contractions. The present study provides comprehensive evidence that slowing of the ventricular rate during AF by selective ganglionic stimulation of the vagal nerves that innervate the AVN successfully improved the hemodynamic responses.

Assessment of LV systolic function in atrial fibrillation using an index of preceding cardiac cycles.

The clinical assessment of left ventricular (LV) systolic function during atrial fibrillation (AF) is unreliable and difficult because of beat-to-beat variability. We evaluated an index for the estimation of LV systolic function in AF that is based on the relationship between the preceding (R-R1) and prepreceding (R-R2) R-R intervals. LV Doppler stroke volume (SV), ejection fraction (EF), peak aortic flow rate (AoF) and the maximum value of the first derivative of the LV pressure curve (dP/dt(max)) were evaluated in 13 healthy open-chest dogs during triggered AF. All parameters showed a significantly strong positive linear relationship with the ratio of R-R1/R-R2 (r = 0.65, 0.74, 0.75, and 0.70 for SV, EF, AoF, and dP/dt(max), respectively). The calculated value of LV systolic parameters at R-R1/R-R2 = 1 in the linear regression line showed a good relationship and an agreement with the measured average value of the parameter over all cardiac cycles (SV, 12.1 vs. 12.8 ml; EF, 49.6 vs. 51.2%; AoF, 1.37 vs. 1.48 l/min; and dP/dt(max), 2,323 vs. 2,454 mmHg/s). Using the LV systolic parameters estimated at R-R1/R-R2 = 1 in the linear regression line allows the LV contractile function to be accurately and reproducibly evaluated during AF and obviates the less-reliable process of averaging multiple cardiac cycles.

Use of transesophageal echocardiography to guide cardioversion in patients with atrial fibrillation.

BACKGROUND: The conventional treatment strategy for patients with atrial fibrillation who are to undergo electrical cardioversion is to prescribe warfarin for anticoagulation for three weeks before cardioversion. It has been proposed that if transesophageal echocardiography reveals no atrial thrombus, cardioversion may be performed safely after only a short period of anticoagulant therapy. METHODS: In a multicenter, randomized, prospective clinical trial, we enrolled 1222 patients with atrial fibrillation of more than two days' duration and assigned them to either treatment guided by the findings on transesophageal echocardiography or conventional treatment. The composite primary end point was cerebrovascular accident, transient ischemic attack, and peripheral embolism within eight weeks. Secondary end points were functional status, successful restoration and maintenance of sinus rhythm, hemorrhage, and death. RESULTS: There was no significant difference between the two treatment groups in the rate of embolic events (five embolic events among 619 patients in the transesophageal-echocardiography group [0.8 percent]) vs. three among 603 patients in the conventional-treatment group [0.5 percent], P=0.50). However, the rate of hemorrhagic events was significantly lower in the transesophageal-echocardiography group (18 events [2.9 percent] vs. 33 events [5.5 percent], P=0.03). Patients in the transesophageal-echocardiography group also had a shorter time to cardioversion (mean [+/-SD], 3.0+/-5.6 vs. 30.6+/-10.6 days, P<0.001) and a greater rate of successful restoration of sinus rhythm (440 patients [71.1 percent] vs. 393 patients [65.2 percent], P=0.03). At eight weeks, there were no significant differences between the two groups in the rates of death or maintenance of sinus rhythm or in functional status. CONCLUSIONS: The use of transesophageal echocardiography to guide the management of atrial fibrillation may be considered a clinically effective alternative strategy to conventional therapy for patients in whom elective cardioversion is planned.

Potential clinical efficacy and cost benefit of a transesophageal echocardiography-guided low-molecular-weight heparin (enoxaparin) approach to antithrombotic therapy in patients undergoing immediate cardioversion from atrial fibrillation.

An alternative clinical management strategy and cost analysis model is presented for patients with atrial fibrillation of >2 days' duration who may benefit from immediate cardioversion with self-administered low-molecular-weight heparin (enoxaparin) as a bridge antithrombotic therapy to warfarin, after a negative transesophageal echo-cardiography (TEE) screening for thrombus. Assuming no difference in stroke or bleeding rates, our cost minimization model shows that the TEE-guided enoxaparin treatment costs are $1353 lower per patient than an intravenous unfractionated heparin approach. Sensitivity analyses for stroke and bleeding reveal that the treatment-cost economic dominance of the TEE-guided enoxaparin approach may be enhanced by an expected improvement in clinical outcome.

Right atrial spontaneous echo contrast and thrombi in atrial fibrillation: a transesophageal echocardiography study.

BACKGROUND: Previous studies have reported the clinical and echocardiographic findings of patients with left atrial spontaneous echo contrast (SEC) and thrombi. We sought to study these characteristics in patients with right atrial SEC and thrombi. METHODS: We reviewed 580 consecutive patients from the ACUTE (Assessment of Cardioversion Using Transesophageal Echocardiography) Registry and found 79 patients (14%, aged 67 +/-13 years, 67 male) with transesophageal echocardiography (TEE) findings of right atrial SEC or thrombi (group 1). This group was compared with a control group of 75 consecutive patients (group 2) (aged 68 +/- 13 years, P = not significant; 49 male, P <.005) from the registry with no TEE findings of SEC or thrombi in the left or right atrium. RESULTS: Atrial fibrillation was present in 60 of 79 group 1 patients (76%). Five right atrial (6%) and 11 left atrial (14%) thrombi were identified. Both left ventricular ejection fraction (39% +/- 16% versus 47% +/- 14%; P =.0005) and presence of right ventricular dysfunction (n = 44 versus 18; P =.0001) differed significantly between groups 1 and 2, respectively. Right atrial area (24 +/- 6 cm(2) versus 22 +/- 6 cm(2); P = .02) was larger in patients in group 1. Left atrial SEC was present in 68 of 79 group 1 patients (86%). Patients with right atrial thrombi and right atrial SEC had a longer duration of arrhythmia (524 +/-812 days versus 147 +/-368 days, P <.05) than patients with right atrial SEC only. CONCLUSIONS: Right atrial SEC has a prevalence of 14% in patients with atrial arrhythmia who undergo TEE-guided cardioversion. Right atrial thrombi are a rare finding and were seen in fewer than 1% (5/580) of patients with atrial arrhythmia. Right atrial thrombi among patients on anticoagulation therapy were not associated with clinically significant pulmonary embolism.

Left ventricular diastolic dysfunction in lone atrial fibrillation determined by Doppler tissue imaging of mitral annular motion.

In this study, we sought evidence for an underlying atrial or ventricular myopathy in patients with paroxysmal lone atrial fibrillation using standard echocardiographic parameters in addition to Doppler tissue imaging of mitral annular motion. No impairment in atrial contractile function was found, but there was evidence for impaired diastolic function in these patients.

Transesophageal echocardiography-guided cardioversion of atrial fibrillation.

Transesophageal echocardiography-guided anticoagulation management of patients with atrial fibrillation undergoing cardioversion has evolved over the past decade as a viable alternative to conventional anticoagulation management. Its use grew out of a need for a more predictable, dependable, and convenient approach to this difficult management dilemma, which has become increasingly prevalent in practice as an increasing number of patients present to clinics and hospitals with atrial fibrillation. In addition to its use in risk stratification of patients scheduled to undergo cardioversion, this management strategy allows for early cardioversion, which enables a minimal delay in proceeding from the diagnosis to the institution of therapy (electrical cardioversion). This review explores the evolution of the transesophageal echocardiography-guided strategy, the advantages and disadvantages of its use, and possible modifications to the strategy that would allow for a more convenient, practical, and more widely acceptable approach in the near future.

National use of the transesophageal echocardiographic-guided approach to cardioversion for patients in atrial fibrillation.

Transesophageal echocardiographic (TEE)-guided cardioversion of patients in atrial fibrillation (AF) of >2 days' duration is used as an alternative to conventional therapy. The purpose of this study was to investigate practice patterns employed for stroke prophylaxis in patients with AF who underwent cardioversion, and to determine the relative use of conventional and TEE-guided management strategies. We forwarded regionally stratified survey questionnaires to 947 clinical practices within the United States. The 10-question questionnaire queried demographic and clinical practice volumes and practices for managing patients with AF who underwent cardioversion. In addition, we used historical data to determine longitudinal use patterns of the TEE-guided approach for a large institution over 7 years. The 197 completed and returned surveys yielded a return rate of 20.8%. The TEE-guided approach was employed in approximately 12% of total cardioversions, but 75% of practices indicated that they employed transesophageal echocardiography only occasionally. The TEE-guided approach was associated with community size (r = 0.19; p<0.008), type of practice (r = 0.26; p = 0.001), total use of transesophageal echocardiography (r = 0.48; p<0.001), and volume of cardioversions (r = 0.28; p<0.001). Importantly, there was little consensus on the most appropriate clinical indications for TEE-guided cardioversions, and the proportions of TEE-guided cardioversion to total number of electrical cardioversions remained stable over 7 years. Practice volume and physician training may be the most important variables in the adoption of the TEE approach.

Reduced survival in women after valve surgery for aortic regurgitation: effect of aortic enlargement and late aortic rupture.

OBJECTIVE: We sought to investigate the relationship of female sex, aortic pathology, and left ventricular function to outcome after an operation for aortic regurgitation. METHODS: One hundred nine women underwent aortic valve replacement (n = 92) or repair (n = 17) for pure aortic regurgitation between 1985 and 1996. Mean follow-up was 5.7 +/- 2.6 years. New York Heart Association functional class III-IV symptoms were present in 70 patients, whereas left ventricular function was normal in 60 patients. Ascending aortic diameter in 97% exceeded the 90th percentile for a size-matched healthy population. A concomitant aortic operation was performed by means of root replacement in 31 patients and by means of interposition graft in 28 patients. Of 50 patients undergoing isolated valve procedures, 19 had aortas of 4.0 cm or larger. RESULTS: At 5 and 10 years, survival was 78% and 44%, respectively. Fatal aortic rupture occurred in 13 patients, and 2 others underwent emergency operations for impending aortic rupture, for a total of 15 late aortic events. Freedom from aortic events was 87% and 76% at 5 and 10 years, respectively. Risk factors for aortic events were older age (P =.07) and increasing ascending aortic diameter indexed to body surface area (P =.03) in women who had not undergone replacement of the ascending aorta. Rupture location was at the ascending aorta in 71% without ascending replacement and the descending aorta in 62% with ascending grafts. CONCLUSION: In women, late survival after an operation for aortic regurgitation is importantly decreased by coexisting aortic pathology with subsequent aortic rupture. Aortic replacement at the time of a valve operation should be considered on the basis of indexed aortic size.

Efficacy of anticoagulation in resolving left atrial and left atrial appendage thrombi: A transesophageal echocardiographic study.

BACKGROUND: Transesophageal echocardiography (TEE) is the gold standard for evaluation of the left atrium and the left atrial appendage (LAA) for the presence of thrombi. Anticoagulation is conventionally used for patients with atrial fibrillation to prevent embolization of atrial thrombi. The mechanism of benefit and effectiveness of thrombi resolution with anticoagulation is not well defined. METHODS AND RESULTS: We used a TEE database of 9058 consecutive studies performed between January 1996 and November 1998 to identify all patients with thrombi reported in the left atrium and/or LAA. One hundred seventy-four patients with thrombi in the left atrial cavity (LAC) and LAA were identified (1.9% of transesophageal studies performed). The incidence of LAA thrombi was 6.6 times higher than LAC thrombi (151 vs 23, respectively). Almost all LAC thrombi were visualized on transthoracic echocardiography (90.5%). Mitral valve pathology was associated with LAC location of thrombi (P <.0001), whereas atrial fibrillation or flutter was present in most patients with LAA location of thrombi. Anticoagulation of 47 +/- 18 days was associated with thrombus resolution in 80.1% of the patients on follow-up TEE. Further anticoagulation resulted in limited additional benefit. CONCLUSIONS: LAC thrombi are rare and are usually associated with mitral valve pathology. Transthoracic echocardiography is effective in identifying these thrombi. LAA thrombi occur predominantly in patients with atrial fibrillation or flutter. Short-term anticoagulation achieves a high rate of resolution of LAA and LAC thrombi but does not obviate the need for follow-up TEE.

Transesophageal echocardiography guided enoxaparin antithrombotic strategy for cardioversion of atrial fibrillation: the ACUTE II pilot study.

BACKGROUND: Patients with atrial fibrillation >2 days' duration for whom immediate cardioversion is desired or required are commonly hospitalized for 4 or more days of antithrombotic therapy with intravenous unfractionated heparin and commencement of oral warfarin. For these early cardioversion patients, self-administered low-molecular-weight heparin (enoxaparin sodium) as "bridge" therapy to warfarin may obviate the need for hospitalization and activated partial thromboplastin time monitoring and thus potentially lower costs and enhance utility. OBJECTIVE: To compare feasibility and safety of a transesophageal echocardiography (TEE)-guided enoxaparin strategy with those of a TEE-guided unfractionated heparin strategy in patients with atrial fibrillation of >2 days' duration undergoing early electrical or chemical cardioversion. DESIGN AND SETTING: This is a randomized, multicenter clinical trial at 11 hospitals in the United States. PATIENTS AND INTERVENTION: Two hundred patients with atrial fibrillation >2 days' duration requiring early chemical or electric cardioversion will be enrolled. TEE-guided intravenous unfractionated heparin bridge therapy will be compared with TEE-guided subcutaneous enoxaparin bridge therapy. OUTCOME MEASURES: Feasibility outcomes are time to hospital discharge, patient quality of life/utility, treatment costs, and sinus rhythm. Safety outcomes are ischemic stroke, transient ischemic attack, systemic embolization, major and minor bleeding, clinical hemodynamic instability, and cardiac and cardioversion-related death for a 5-week period from enrollment. CLINICAL IMPLICATIONS: The results of this pilot study will have important clinical and economic implications for the antithrombotic management of patients with atrial fibrillation undergoing TEE-guided cardioversion.

Atrial fibrillation early postoperatively following minimally invasive cardiac valvular surgery.

We report a cohort of our first 100 minimally invasive cardiac valvular operations matched 1:1 by age and valvular surgery type with patients undergoing a traditional midline sternotomy approach. The prevalence of postoperative atrial fibrillation among patients with minimally invasive procedures versus traditional midline sternotomy was 26.3% versus 38.0%, respectively (p = 0.08). Neither multiple logistic regression nor Kaplan-Meier distribution analysis identified differences in postoperative atrial fibrillation between the 2 surgical techniques.

Noninvasive assessment of left atrial maximum dP/dt by a combination of transmitral and pulmonary venous flow.

OBJECTIVES: The study assessed whether hemodynamic parameters of left atrial (LA) systolic function could be estimated noninvasively using Doppler echocardiography. BACKGROUND: Left atrial systolic function is an important aspect of cardiac function. Doppler echocardiography can measure changes in LA volume, but has not been shown to relate to hemodynamic parameters such as the maximal value of the first derivative of the pressure (LA dP/dt(max)). METHODS: Eighteen patients in sinus rhythm were studied immediately before and after open heart surgery using simultaneous LA pressure measurements and intraoperative transesophageal echocardiography. Left atrial pressure was measured with a micromanometer catheter, and LA dP/dt(max) during atrial contraction was obtained. Transmitral and pulmonary venous flow were recorded by pulsed Doppler echocardiography. Peak velocity, and mean acceleration and deceleration, and the time-velocity integral of each flow during atrial contraction was measured. The initial eight patients served as the study group to derive a multilinear regression equation to estimate LA dP/dt(max) from Doppler parameters, and the latter 10 patients served as the test group to validate the equation. A previously validated numeric model was used to confirm these results. RESULTS: In the study group, LA dP/dt(max) showed a linear relation with LA pressure before atrial contraction (r = 0.80, p < 0.005), confirming the presence of the Frank-Starling mechanism in the LA. Among transmitral flow parameters, mean acceleration showed the strongest correlation with LA dP/dt(max) (r = 0.78, p < 0.001). Among pulmonary venous flow parameters, no single parameter was sufficient to estimate LA dP/dt(max) with an r2 > 0.30. By stepwise and multiple linear regression analysis, LA dP/dt(max) was best described as follows: LA dP/dt(max) = 0.1 M-AC +/- 1.8 P-V - 4.1; r = 0.88, p < 0.0001, where M-AC is the mean acceleration of transmitral flow and P-V is the peak velocity of pulmonary venous flow during atrial contraction. This equation was tested in the latter 10 patients of the test group. Predicted and measured LA dP/dt(max) correlated well (r = 0.90, p < 0.0001). Numerical simulation verified that this relationship held across a wide range of atrial elastance, ventricular relaxation and systolic function, with LA dP/dt(max) predicted by the above equation with r = 0.94. CONCLUSIONS: A combination of transmitral and pulmonary venous flow parameters can provide a hemodynamic assessment of LA systolic function.

Analysis of risk factors for development of atrial fibrillation early after cardiac valvular surgery.

Atrial fibrillation (AF) commonly develops after cardiac valvular surgery. The objective of this study was to identify risk factors for postoperative AF following valvular surgery. A cohort of 915 consecutive adult patients undergoing isolated valvular surgery with preoperative sinus rhythm was analyzed. Univariate and independent multivariate risk factors for postoperative AF were determined. A second cohort of 305 patients with the same inclusion criteria was used to validate the multivariate predictors. Patients studied had a mean age of 56.1 +/- 14.7 years, 57.9% were men, 79.6% had a normal left ventricular ejection fraction, and their mean left atrial size was 46.2 +/- 9.3 mm. The incidence of postoperative AF was 36.7%. Independent predictors of postoperative AF included: advanced age (odds ratio [OR] 1.506 per decade, 95% confidence interval, [CI] 1.35 to 1.68, p = 0.0001); mitral stenosis (OR 2.066, CI 1.21 to 3.52, p = 0.0077); left atrial enlargement (OR 1.468, CI 1.07 to 2.01, p = 0.0165); use of systemic hypothermia (OR 0.572, CI 0.422 to 0.776, p = 0.0003); and a history of cardiac surgery (OR 0.676, CI 0.465 to 0.981, p = 0.0393). Among these variables, advanced age, mitral stenosis, and left atrial enlargement were confirmed as independent risk factors in the validation cohort.

The role of intraoperative echocardiography in valve surgery.

The widespread use and popularity of intraoperative echocardiography (IOE) has resulted from advances in cardiac surgery, reparative procedures for valvular heart disease and, most specifically, mitral valve repair. IOE has grown exponentially and is becoming an integral part of the planning and evaluation of many types of surgical procedures such that it is now considered standard of care especially for the perioperative management of patients undergoing mitral and aortic valve repair. This article discusses the application of intraoperative echocardiography and focus specifically on valvular heart disease as this represents the most widely accepted indication for the procedure in current clinical practice.