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Despite the prevalence of atrial fibrillation (AF), estimated at 0.9% of the population,1 and the extensive investigation into its pathophysiology, the relative contribution of structural and electrophysiologic processes in the initiation of AF remain to be fully elucidated. Historically, the assessment of atrial function has been problematic. Mitral annular excursion has been used as an index of atrial function, both in baseline conditions and after cardioversion from AF.2‐ 4 Doppler tissue imaging (DTI) allows for the rapid assessment of mitral annular excursion velocities and hence adds to the assessment of atrial contractile function, as well as being a useful parameter in the interrogation of ventricular diastolic function. 5,6 This study examines whether patients with lone AF exhibit abnormalities in atrial function or ventricular filling using 2-dimensional, pulsed-wave Doppler and DTI indexes of atrial contractile and ventricular diastolic function. ••• We studied 24 patients with paroxysmal lone AF and

The data from the present nonrandomized observational study of 350 older persons with chronic atrial fibrillation showed that compared with aspirin, warfarin administered in a dose to maintain an INR between 2.0 and 3.0 caused a 40% significant reduction in thromboembolic stroke in persons with prior stroke, a 31% significant decrease in thromboembolic stroke in persons with no prior stroke, a 45% significant reduction in thromboembolic stroke in persons with abnormal LV ejection fraction, and a 36% significant decrease in thromboembolic stroke in persons with normal LV ejection fraction. Cox regression analysis showed that the use of warfarin in this study was a significant independent risk factor for reducing new thromboembolic stroke by 67%.

OBJECTIVES: To determine the effect of preload in color M-mode Doppler flow propagation velocity (v(p)). BACKGROUND: The interpretation of Doppler filling patterns is limited by confounding effects of left ventricular (LV) relaxation and preload. Color M-mode v(p) has been proposed as a new index of LV relaxation. METHODS: We studied four dogs before and during inferior caval (IVC) occlusion at five different inotropic stages and 14 patients before and during partial cardiopulmonary bypass. Left ventricular (LV) end-diastolic volumes (LV-EDV), the time constant of isovolumic relaxation (tau), left atrial (LA) pre-A and LV end-diastolic pressures (LV-EDP) were measured. Peak velocity during early filling (E) and v(p) were extracted by digital analysis of color M-mode Doppler images. RESULTS: In both animals and humans, LV-EDV and LV-EDP decreased significantly from baseline to IVC occlusion (both p < 0.001). Peak early filling (E) velocity decreased in animals from 56 +/- 21 to 42 +/- 17 cm/s (p < 0.001) without change in v(p) (from 35 +/- 15 to 35 +/- 16, p = 0.99). Results were similar in humans (from 69 +/- 15 to 53 +/- 22 cm/s, p < 0.001, and 37 +/- 12 to 34 +/- 16, p = 0.30). In both species, there was a strong correlation between LV relaxation (tau) and v(p) (r = 0.78, p < 0.001, r = 0.86, p < 0.001). CONCLUSIONS: Our results indicate that color M-mode Doppler v(p) is not affected by preload alterations and confirms that LV relaxation is its main physiologic determinant in both animals during varying lusitropic conditions and in humans with heart disease.

We evaluated diastolic filling patterns using Doppler echocardiography in 520 consecutive patients referred to our laboratory for transthoracic echocardiograms retrospectively and applied the standard guidelines used to characterize left ventricular (LV) diastolic function. Patients were classified by the Canadian consensus guidelines using transmitral and pulmonary venous Doppler echocardiographic parameters to have normal diastolic function or mild (abnormal relaxation), mild-to-moderate, moderate (pseudonormal), or severe (restrictive) diastolic dysfunction. LV diastolic dysfunction was present in 290 (56%) patients, whereas 167 (45%) patients with a normal LV ejection fraction had abnormal diastolic function. Patients with progressively more abnormal diastolic patterns had greater structural abnormalities with larger left atrial and LV size and lower LV ejection fractions. In the subset of patients with clinical evidence of congestive heart failure (99 patients), the prevalence of primary diastolic heart failure was 38% and most patients had underlying coronary or hypertensive heart disease. Standard guidelines of Doppler echocardiographic parameters allow semiquantitation of diastolic function and can be applied to studying large number of patients in a large clinical practice. (J Am Soc Echocardiogr 2002;15:1237-44.)

This series on contrast echocardiography has previously discussed the value of this technique for the improvement of endocardial border definition in technically challenging patients. The echocardiographic assessment of left ventricular (LV) regional performance can be significantly improved by using LV opacification (LVO) produced by the injection of contrast microbubbles into a peripheral vein. On the basis of years of investigational work, it is now apparent that myocardial contrast echocardiography (MCE) may offer an additional clinical benefit by assessing regional myocardial perfusion. Investigators have recently presented encouraging results using echocardiographic contrast agents for the assessment of myocardial perfusion under optimal imaging conditions. In this final article of the series on contrast, we will provide some basic information on the use of MCE for the assessment of myocardial perfusion. As always, we refer you to more detailed explanations in the listed references. Currently, nuclear imaging that uses thallium or sestamibi scintigraphy is the only clinical technique used to assess myocardial perfusion. In comparison, MCE is less expensive, portable, and does not use ionizing radiation. MCE uses an intravascular tracer and demonstrates better spatial resolution. Contrast microbubbles injected into a peripheral vein, the aortic root, or directly into the coronary arteries are designed to travel through the cardiovascular circulation in a manner similar to red blood cells. These microbubbles not only fill the LV cavity as see during LVO, but they also traverse the epicardial coronary vessels into the myocardial capillaries. The concentration of microbubbles in the myocardial capillary bed is far less than found within the LV cavity after an intravenous injection, so specialized techniques have been developed to detect contrast microbubbles for the assessment of myocardial perfusion. These techniques and the clinical benefits of assessing myocardial perfusion will be discussed in more detail.

Background: Newer contrast agents as well as tissue harmonic imaging enhance left ventricular (LV) endocardial border delineation, and therefore, improve LV wall-motion analysis. Interpretation of dobutamine stress echocardiography is observer-dependent and requires experience. This study was performed to evaluate whether these new imaging modalities would improve endocardial visualization and enhance accuracy and efficiency of the inexperienced reader interpreting dobutamine stress echocardiography. Methods and Results: Twenty-nine consecutive patients with known or suspected coronary artery disease underwent dobutamine stress echocardiography. Both fundamental (2.5 MHZ) and harmonic (1.7 and 3.5 MHZ) mode images were obtained in four standard views at rest and at peak stress during a standard dobutamine infusion stress protocol. Following the noncontrast images, Optison was administered intravenously in bolus (0.5–3.0 ml), and fundamental and harmonic images were obtained. The dobutamine echocardiography studies were reviewed by one experienced and one inexperienced echocardiographer. LV segments were graded for image quality and function. Time for interpretation also was recorded. Contrast with harmonic imaging improved the diagnostic concordance of the novice reader to the expert reader by 7.1%, 7.5%, and 12.6% (P < 0.001) as compared with harmonic imaging, fundamental imaging, and fundamental imaging with contrast, respectively. For the novice reader, reading time was reduced by 47%, 55%, and 58% (P < 0.005) as compared with the time needed for fundamental, fundamental contrast, and harmonic modes, respectively. With harmonic imaging, the image quality score was 4.6% higher (P < 0.001) than for fundamental imaging. Image quality scores were not significantly different for noncontrast and contrast images. Conclusion: Harmonic imaging with contrast significantly improves the accuracy and efficiency of the novice dobutamine stress echocardiography reader. The use of harmonic imaging reduces the frequency of nondiagnostic wall segments.

Background — Myocardial fiber strain is directly related to left ventricular (LV) contractility. Strain rate can be estimated as the spatial derivative of velocities (dV/ds) obtained by tissue Doppler echocardiography (TDE). The purposes of the study were (1) to determine whether TDE-derived strain rate may be used as a noninvasive, quantitative index of contractility and (2) to compare the relative accuracy of systolic strain rate against TDE velocities alone. Methods and Results — TDE color M-mode images of the interventricular septum were recorded from the apical 4-chamber view in 7 closed-chest anesthetized mongrel dogs during 5 different inotropic stages. Simultaneous LV volume and pressure were obtained with a combined conductance–high-fidelity pressure catheter. Peak elastance (E max ) was determined as the slope of end-systolic pressure-volume relationships during caval occlusion and was used as the gold standard of LV contractility. Peak systolic TDE myocardial velocities (S m ) and peak (ε′ p ) and mean (ε′ m ) strain rates obtained at the basal septum were compared against E max by linear regression. E max as well as TDE systolic indices increased during inotropic stimulation with dobutamine and decreased with the infusion of esmolol. A stronger association was found between E max and ε′ p ( r =0.94, P y =0.29 x +0.46) and ε′ m ( r =0.88, P m ( r =0.75, P Conclusions — TDE-derived ε′ p and ε′ m are strong noninvasive indices of LV contractility. These indices appear to be more reliable than S m , perhaps by eliminating translational artifact.

Myocardial tissue Doppler echocardiography (TDE) has been proposed as a tool for the assessment of diastolic function. Controversy exists regarding whether TDE measurements are influenced by preload. In this study, left ventricular volume and high-fidelity pressures were obtained in eight closed-chest dogs during intermittent caval occlusion. The time constant of isovolumic ventricular relaxation (τ) was altered with varying doses of dobutamine and esmolol. Peak early diastolic myocardial ( E m) and transmitral ( E) velocities were measured before and after preload reduction. The relative effects of changes in preload and relaxation were determined for E m and compared with their effects on E. The following results were observed: caval occlusion significantly decreased E (Δ E = 16.4 ± 3.3 cm/s, 36.6 ± 13.7%, P < 0.01) and E m (Δ E m = 1.3 ± 0.4 cm/s, 32.5 ± 26.1%, P < 0.01) under baseline conditions. However, preload reduction was similar for E under all lusitropic conditions ( P = not significant), but these effects on E m decreased with worsening relaxation. At τ < 50 ms, changes in E m with preload reduction were significantly greater (Δ E m = 2.8 ± 0.6 cm/s) than at τ = 50–65 ms (Δ E m = 1.2 ± 0.2 cm/s) and at τ >65 ms (Δ E m = 0.5 ± 0.1 cm/s, P < 0.05). We concluded that TDE E m is preload dependent. However, this effect decreases with worsening relaxation.

The Maze procedure for atrial arrhythmias is designed to eliminate atrial fibrillation, and preserve atrial function. Initial data after short-term follow-up indicates that 60% patients show restoration of atrial systolic function. The long-term evaluation by echo-Doppler of left and right atrial function has not been well studied. We performed pulsed Doppler and two dimensional echocardiographyon 19 patients (16 males, mean age 54 years) who underwent the Maze procedure for atrial fibrillation and who had a follow-up study greater than 3 months (mean duration = 17 months) after the procedure. Measurements included the peak left ventricular (LV) inflow and right ventricular (RV) inflow A-wave velocity, maximum (Max) and minimum (Min) off-line digitized left atrial (LA) and right atrial (RA) areas and fractional area change (FAC). Left Atrium Right Atrium Pre Post Pre Post Max (cm 2 ) 26.1 23.1 20.8 21.7 Min (cm 2 ) 19.6 18.1 16.0 17.6 FAC (%) 27.0 22.0 23. 20.0 Twelve patients (63%) had evidence of LA function, while 16 patients (84%) had evidence of RA function. The LV inflow A-wave velocity (33 ± 9 cm/s) and the RV inflow A-wave velocity (35 ± 12 cm/s) did not differ significantly; however, the LA inflow A-wave was significantly lower than agematched controls (59 ± 14, p l 0.001). Both the mean LA FAC and the RA FAC tended to decrease at follow-up (p = 0.13). Conclusions 1) In long-term follow-up of 17 months after the Maze procedure, left atrial systolic function is preserved in 63% of patients, while the right atrial systolic function is preserved in 86% of patients. 21 LA peak A-wave velocity post Maze is considerably less than that shown in agematched controls. These findings suggest that the Maze procedure is only partially successful in achieving its goals of preserving atrial function.

Objectives.This study sought to establish the prognostic implications of ischemic and viable myocardium identified by dobutamine echocardiography in patients with left ventricular dysfunction.Background.Recent studies have suggested that in patients with viable myocardium identified by positron emission tomography, medical treatment is associated with recurrent cardiac events. Dobutamine echocardiography has been used to identify viable myocardium in patients with left ventricular dysfunction, but the prognostic significance of this test is undefined.Methods.One hundred thirty-six consecutive patients (mean [±SD] age 67 ± 7.9 years; 104 men) with moderate or severe left ventricular dysfunction (left ventricular ejection fraction 30 ± 5%) undergoing dobutamine echocardiography were included in the study. Dobutamine was administered using a standard incremental protocol (5 to 40 μg/kg body weight per min intravenously in 3-min stages) with additional atropine (1 mg intravenously) as required. Standard body weight echocardiographic views were digitized on-line and compared using a side-by-side display. Viable myocardium was identified by enhancement of regional function at low dose (