Disparities in emptying velocity within the left atrial appendage.

AIMS: Pulsed Doppler measurement of left atrial appendage (LAA) emptying velocity, a marker of left atrium contractile function, has been shown to predict success of cardioversion, thrombo-embolic risk, and maintenance of sinus rhythm after cardioversion and pulmonary vein isolation. However, in the published literature, emptying velocity measurement location is not uniform, and no standard currently exists. We assessed the hypothesis that emptying velocity when acquired near the LAA orifice differs from that at the LAA apex. METHODS AND RESULTS: The study group comprised 44 patients (32 in sinus rhythm and 12 in atrial fibrillation) who were able to complete a non-emergent transoesophageal echocardiography. Pulsed Doppler recordings were obtained with the sample volume first positioned 1 cm from the LAA orifice, and then positioned within 1 cm of the LAA apex. At each location, we calculated the average of the peak end-diastolic LAA emptying velocity from five consecutive cardiac cycles. LAA orifice emptying velocity was higher than the apex emptying velocity in all patients. The median velocity at the orifice was 72 cm/s, which was 45% higher than the median velocity at the apex (43 cm/s, P < 0.001). Lower LAA emptying velocity at the orifice was associated with a larger discrepancy between orifice and apex velocities. The ratio of orifice to apex velocity did not vary with orifice velocity. Multivariate analysis demonstrated that clinical patient characteristics were not significant predictors of the discrepancy between orifice and apex velocities. CONCLUSION: LAA emptying velocity is greater at the LAA orifice compared with the LAA apex. Higher, more easily measured velocity and greater variability observed with orifice measurements make it the location of choice for research and clinical applications.

Clinical utility of intraprocedural transesophageal echocardiography during transvenous lead extraction.

BACKGROUND: Transvenous lead extraction carries a risk of significant complications. Although intraoperative transesophageal echocardiography (TEE) is widely used to monitor cardiac performance and structures, its utility during transvenous lead extraction has not been well described. OBJECTIVE: This study evaluates the utility of TEE during transvenous lead extraction. METHODS: The records of 108 consecutive patients who underwent transvenous lead extraction with TEE guidance were reviewed. RESULTS: Transvenous extraction of 202 leads was attempted; complete extraction was achieved for 174 leads (86%) and partial extraction for 13 leads with clinically acceptable outcomes in 187 leads (93%). Mean age of the patients was 63 +/- 21 (14-99) years and 37% were female. The average number of leads per patient was 1.9 (1-6). Mean implant duration was 71 +/- 57 (1-360) months. Indications for extraction were pocket infection (53 patients), bacteremia (33), atrial J-lead fracture or recall (13), lead malfunction (8), and venous thrombosis (1). TEE identified critical findings that prompted emergency surgical intervention or converted transvenous lead extraction to surgical explantation in 6 patients (two cases with cardiac laceration, 3 cases of cardiac tamponade, and one case with a large vegetation and a patent foramen ovale). TEE eliminated the need for the premature termination of the procedure in 11 patients by excluding significant structural cardiac damage. Overall, TEE provided clinically useful information during transvenous lead extraction in 17 cases (16%). CONCLUSIONS: TEE during transvenous lead extraction provides valuable real-time information that improves efficacy and safety.

Demonstration of left ventricular outflow tract eccentricity by real time 3D echocardiography: implications for the determination of aortic valve area.

BACKGROUND: Determination of the left ventricular outflow tract cross-sectional area (ALVOT) is necessary for calculating aortic valve area (AVA) by echocardiography using the continuity equation (CE). In the commonly applied form of CE, pir(2) is used to estimate ALVOT utilizing the assumptions that LVOT is round and the parasternal long axis (PLAX) plane bisects LVOT. Imaging LVOT using real time 3D echocardiography (RT3DE) eliminates the need for these assumptions. We tested the hypothesis that LVOT is round based on a formula for eccentricity. METHODS AND RESULTS: In 53 patients, 2D echocardiography (2DE) and RT3DE were acquired. ALVOT was calculated by 2DE using pir(2) (ALVOT-2D). Using RT3DE, ALVOT planimetry was performed immediately beneath the aortic valve (ALVOT-3Dplan). Eccentricity Index (EI) was calculated using the shortest and longest LVOT diameters. The long axis was measured to be larger by 0.53 cm +/- 0.36 (P < 0.005). The median EI was 0.20 (0.00-0.54), indicating that half the subjects had at least a 20% difference between the major and minor diameters. ALVOT-3Dplan was larger than ALVOT-2D (3.73 +/- 0.95 cm(2) vs. 3.18 +/- 0.73 cm(2); P < 0.001) by paired analysis. Using the equation of an ellipse (piab), ALVOT-3Dellip was 3.57 +/- 0.95 resulting in improved agreement with ALVOT-3Dplan. CONCLUSIONS: In our small patient sample with normal aortic valves, we showed the LVOT shape is usually not round and frequently, elliptical. Incorrectly assuming a round LVOT underestimated the ALVOT-3Dplan and consequently the AVA by 15%. Investigating the LVOT in aortic stenosis is warranted to evaluate whether RT3DE may improve measurement of AVA.

Noncompaction of the left ventricle in a patient with dextroversion.

Noncompaction of the left ventricle is a rare, congenital cardiomyopathy characterized by excessive trabeculation of the myocardium. Dextrocardia with situs solitus, commonly referred to as dextroversion, is associated with additional congenital heart disease. We report a case of noncompaction of the left ventricle in a patient with dextroversion, an association of which has not been previously described.

Pseudodyskinesis--a novel mechanism for abnormal motion of the heart's diaphragmatic wall.

We report a case of pseudodyskinesis, where there is dyssynchronous contraction of the heart's diaphragmatic wall despite normal wall thickening. This finding has previously been reported in a small group of patients with liver disease, and has been attributed to elevation of the diaphragm as a result of hepatomegaly and ascites. Our case demonstrates similar findings in a patient without liver disease, in whom the diaphragm was elevated secondary to volume loss in the chest. Our case supports the assertion that diaphragmatic elevation, regardless of cause, is indeed responsible for this probably common echocardiographic finding.

Biventricular mural vegetations in a patient without valvular pathology.

We present the case of a 40 year-old man with biventricular nonvalvular vegetations presenting with acute onset of unilateral hearing loss and headache as a result of septic emboli. The medical literature involving the rare diagnosis of mural vegetation is reviewed and unusual features of this case are discussed.

Free-floating left atrial ball thrombus following mitral valve replacement.

We report the case of a 51-year-old woman who underwent mitral valve replacement for prolapse with severe regurgitation, depressed ejection fraction, and atrial fibrillation. Two weeks post-operatively, a transesophageal echocardiogram was performed for bacteremia. The patient was found incidentally to have a large free-floating ball thrombus in the left atrium. The patient was managed with anticoagulation because of the high-risk nature of repeat surgery. One month following diagnosis, the patient still had persistent thrombus in the left atrium seen on transthoracic echocardiography despite therapeutic anticoagulation. Free-floating ball thrombus is a rare and dramatic finding seen on echocardiography in patients with mitral valve disease.

Usefulness of myocardial perfusion echocardiography to identify obstructive coronary artery disease in patients with abnormal ventricular septal motion.

Twenty-three patients who had septal wall motion abnormalities and who underwent angiography within 2 weeks were evaluated by myocardial perfusion echocardiography. Mean perfusion score (plateau video intensity times the wash-in rate) was lower in segments that were supplied by obstructed coronary arteries in real time (7.5 vs 22.6 dB/s, p <0.005) and with end-systolic triggering (8.6 vs 20.9 dB/s, p <0.001). Lower mean septal perfusion scores (<12 dB/s) were seen in 14 of 16 patients who had obstructive septal coronary artery disease, and normal mean septal perfusion scores were seen in 6 of 7 patients who did not have obstructive septal coronary artery disease.

Stress radionuclide myocardial perfusion imaging detects more residual ischemia than stress echocardiography following acute myocardial infarction.

OBJECTIVES: This investigation sought to compare the abilities of stress radionuclide myocardial perfusion imaging and stress echocardiography to detect residual ischemia in patients following acute myocardial infarction (MI). BACKGROUND: Stress radionuclide myocardial perfusion imaging and stress echocardiography are both commonly used to assess patients (patients.) in the immediate post MI period. However, the relative value of these techniques in identifying post MI ischemia remains unclear. METHODS: Eighteen patients. underwent both dipyridamole radionuclide perfusion imaging and dobutamine stress echocardiography on the same day or on consecutive days, 3-7 days following uncomplicated acute MI. Pts. who had an acute percutaneous intervention were excluded. Images were reviewed with clinical information available, but blinded to the opposing modality, for perfusion defects, wall motion abnormalities (WMA), and evidence of ischemia (reversible defect(s) on perfusion imaging, worsening WMA on stress echocardiography). Of the 18 patients, 11 subsequently underwent cardiac catheterization. RESULTS: Perfusion imaging identified defects in 16 (89%) patients, of whom 15 (83% of total) were found to be ischemic. Stress echocardiography identified a fixed wall motion abnormality in 17 (94%) and ischemia in 8 (44%, p < 0.05 compared with perfusion imaging ischemia). Among 11 patients who underwent catheterization, there was a trend towards perfusion imaging identifying more ischemia in the territory of an obstructed (> or = 70%) vessel--100% (11/11) vs. 64% (7/11) for stress echocardiography (p = 0.09). CONCLUSION: In the immediate post-infarction period, dipyridamole stress radionuclide myocardial perfusion imaging more often shows evidence of residual ischemia than dobutamine stress echocardiography.