Craig S. Vinch

Direct Ultrasound Measurement of Longitudinal, Circumferential, and Radial Strain Using 2‐Dimensional Strain Imaging in Normal Adults

Current noninvasive techniques used to evaluate left ventricular systolic function are limited by dependence on the angle of insonation (tissue Doppler imaging/TDI) or limited by availability (MRI tagging). We utilized 2‐dimensional speckle strain (ε) imaging (1) to establish normal values for all three ε vectors; (2) to compare circumferential ε values with circumferential shortening (midwall fractional shortening (FSmw); (3) to examine the relationship between left ventricular ε and wall stress; and (4) to compare 2D echocardiographic characteristics by gender. Echocardiography was performed in 60 normal subjects (mean 39 ± 15 years). Small, but significant regional heterogeneity was seen in circumferential ε, but not in radial or longitudinal ε. We found an inverse correlation between circumferential ε and stress (r =−0.29, p<0.05) as well as longitudinal ε and stress (r =−0.11, P < 0.05), though the relationships were not close. We also observed a linear relationship between mean circumferential ε and FSmw (r = 0.29, P < 0.05). In conclusion, (1) 2‐dimensional ε imaging permits measurement of regional systolic ε values in the majority of normal individuals; (2) ε values furnished by this method obey expected stress‐shortening relationships; (3) systolic ε displays minor regional heterogeneity in the circumferential direction; (4) for the first time, a close relationship between FSmw and mean circumferential ε was demonstrated; and (5) there are minor gender‐related differences in LV geometry and function.

Influence of image quality on the accuracy of real time three-dimensional echocardiography to measure left ventricular volumes in unselected patients: a comparison with gated-SPECT imaging.

Background: Patient selection, often restricted to those with ideal image quality, and timing of studies in relation to reference methods may limit clinical applicability of cardiac volumes derived from 3D echocardiography. Methods: To test the influence of image quality on LV volumes by real time 3DE (RT3DE), we compared results obtained by RT3DE to those from gated‐SPECT imaging in 64 consecutive patients referred for clinically indicated nuclear perfusion imaging. To minimize hemodynamic effects, RT3DE was performed immediately following G‐SPECT. LV volumes by RT3DE were calculated using at least three orthogonal plane pairs. Image quality was rated as good if 75–100% of the endocardial border was visualized, fair if 60–74% was visualized, and poor if 50–60% was visualized. Results: Image quality was good in 25 (39%), fair in 20 (31%), and poor in 13 (20%) patients. Six patients (9%) were excluded for uninterpretable echo images. For the entire cohort, EDV and ESV agreed closely (all P = NS). When stratified by image quality, the EDV and ESV of those with good and fair image quality agreed closely with minimal bias (average 1 ± 9 mL and 2 ± 7 mL, respectively). Poor image was associated with less strong agreement and much greater bias for EDV and ESV (7 ± 25 mL and 7 ± 20 mL, respectively). Conclusions: When applied to patients studied in routine clinical practice, LV volumes by RT3DE compare favorably to G‐SPECT. RT3DE results are more reliable when >60% of endocardium is visualized.

Brain Natriuretic Peptide Levels Fall Rapidly after Cardioversion of Atrial Fibrillation to Sinus Rhythm

Background: Brain natriuretic peptide (BNP) levels have been reported to fall following cardioversion of atrial fibrillation (AF). The mechanism for the fall in BNP has not been elucidated and the potential confounding effects of sedation have not been investigated. Sedation may alter BNP levels via its effects on loading conditions. Accordingly, we studied whether BNP levels change shortly after cardioversion and attempted to control for possible effects of sedation. Methods: BNP levels were obtained before and after cardioversion in patients with AF and in a control group of patients undergoing intravenous conscious sedation for transesophageal echocardiography. Results: BNP levels dropped (260 ± 255 vs. 190 ± 212 pg/ml, p < 0.05) 40 min after cardioversion, decreasing in 33 of 41 subjects who achieved sinus rhythm. By contrast, mean BNP did not fall in subjects in whom cardioversion was not successful. The change in BNP level was not related to the degree of change in heart rate. No control subject experienced a change in cardiac rhythm; BNP levels increased (195 ± 407 vs. 238 ± 458 pg/ml, p < 0.05) in 18/22 subjects after sedation. Baseline BNP levels were elevated in subjects with AF, and BNP levels were elevated in parallel with heart failure symptoms. Conclusions: The rapid fall in BNP after cardioversion (1) may reflect prompt hemodynamic improvement associated with rhythm change and (2) does not appear to be due to the effects of sedation.

Book Review: Textbook of Clinical Echocardiography, Third Edition

Echocardiography provides invaluable clinical information, which is attested to by its wide and frequent use, and a practical, authoritative clinical echocardiography text is an asset. Professor Catherine Otto has once again expertly crafted a readable, succinct, and thorough clinical echocardiography text in this third edition. The book fits comfortably beside a laptop computer in its case with barely a noticeable increase in weight. A compact frame belies the trove of significant echocardiographic knowledge that is skillfully presented. I was immediately impressed with the skillful use of color in anatomic figures to give the appearance of depth and texture. Cutaways highlight the underlying anatomy in the figures, and there is thoughtful correlation of the figures with adjacent high-quality echocardiographic images. The still two-dimensional echocardiographic images are of such superb quality that one waits for them to come to life. Accompanying DVDs with looped image files may add important dimensions of understanding to future editions of all echocardiography texts. Although the book is inherently visual, an astute echocardiographer must have wide knowledge in physiology and cardiology. Professor Otto’s prose demonstrates a unique ability to concisely convey salient details in a readily comprehensible manner; this book is well written. The book covers the field so well that I could find few areas in which I sought more information. The section on contrast imaging describes the importance of optimizing instrument setting for microbubble contrast, and more information on harmonic imaging with microbubbles would be useful to busy sonographers and clinicians. Chapter 3 on transesophageal echocardiography (TEE) is particularly useful to cardiology fellows and those trained before the advent of TEE. Neurologists and electrophysiologists are increasingly requesting TEE in stroke patients, before and after atrial fibrillation ablations, and before cardioversion. Approaches to the challenges of completely visualizing the left atrial appendage and distinguishing thrombus from normal anatomy might be useful to trainees or those who infrequently perform TEE. A discussion of the multiplane assessment of the interatrial septum might similarly be useful. Highly relevant information is clearly presented in well-organized and understandable formats in Professor Otto’s tables. Chapter references were well chosen, and the author’s annotations are insightful. My mentors had prior editions on their desks, and I have already used this newest edition in my clinical and teaching roles. Professor Otto is to be thanked for this and her numerous other contributions to echocardiography and medicine.