David N. Rubin

Outcome of patients with hypertrophic obstructive cardiomyopathy after percutaneous transluminal septal myocardial ablation and septal myectomy surgery.

OBJECTIVES This study was conducted to evaluate follow-up results in patients with hypertrophic obstructive cardiomyopathy (HOCM) who underwent either percutaneous transluminal septal myocardial ablation (PTSMA) or septal myectomy. BACKGROUND Controversy exists with regard to these two forms of treatment for patients with HOCM. METHODS Of 51 patients with HOCM treated, 25 were treated by PTSMA and 26 patients via myectomy. Two-dimensional echocardiograms were performed before both procedures, immediately afterwards and at a three-month follow-up. The New York Heart Association (NYHA) functional class was obtained before the procedures and at follow-up. RESULTS Interventricular septal thickness was significantly reduced at follow-up in both groups (2.3 +/- 0.4 cm vs. 1.9 +/- 0.4 cm for septal ablation and 2.4 +/- 0.6 cm vs. 1.7 +/- 0.2 cm for myectomy, both p < 0.001). Estimated by continuous-wave Doppler, the resting pressure gradient (PG) across the left ventricular outflow tract (LVOT) significantly decreased immediately after the procedures in both groups (64 +/- 39 mm Hg vs. 28 +/- 29 mm Hg for PTSMA, 62 +/- 43 mm Hg vs. 7 +/- 7 mm Hg for myectomy, both p < 0.0001). At three-month follow-up, the resting PG remained lower in the PTSMA and myectomy groups (24 +/- 19 mm Hg and 11 +/- 6 mm Hg, respectively, vs. those before procedures, both p < 0.0001). The NYHA functional class was also significantly improved in both groups (3.5 +/- 0.5 vs. 1.9 +/- 0.7 for PTSMA, 3.3 +/- 0.5 vs. 1.5 +/- 0.7 for myectomy, both p < 0.0001). CONCLUSIONS Both myectomy and PTSMA reduce LVOT obstruction and significantly improve NYHA functional class in patients with HOCM. However, there are benefits and drawbacks for each therapeutic method that must be counterbalanced when deciding on treatment for LVOT obstruction.

Tissue harmonic imaging: Why does it work?☆☆☆★★★

The recent utilization of harmonic frequencies in the imaging of both tissue and contrast agents has dramatically improved echocardiographic image quality. In contrast harmonics, the harmonic frequency energy is generated on reflection from the microbubble contrast agent. In tissue harmonics, the harmonic frequency energy is generated gradually as the ultrasonic wave propagates through the tissue. Critical to the utility of tissue-generated harmonic frequencies is their origin beyond the chest wall and their nonlinear relation to the fundamental frequency energy strength. These two characteristics of tissue-generated harmonics ensure that the echoes most likely to produce artifact are least likely to produce harmonic waves. Armed with an understanding of how these images are produced and with data emerging as to their clinical utility, we anticipate that harmonic imaging will become the standard for assessing regional and global left ventricular function in technically difficult studies.

Contrast and harmonic imaging improves accuracy and efficiency of novice readers for dobutamine stress echocardiography.

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.

Outcomes and cost implications of a clinical-based algorithm to guide the discriminate use of stress imaging before noncardiac surgery

Approximately 8 million patients at risk for coronary artery disease undergo noncardiac surgery annually in the United States. This study defined the appropriateness and cost of evaluating these patients with stress imaging tests. Before noncardiac surgery, 178 consecutive patients were prospectively studied by stress imaging. Pretest cardiac risk (low, intermediate, high) was established by interviewing the referring physician and separately by a cardiologist on the basis of the nature of noncardiac surgery and Eagles clinical criteria. Patients were followed-up for alterations in management and perioperative events until hospital discharge. Referring physicians and cardiologists identified low risk in 24% and 54% of patients, respectively (p < 0.0001). Of 96 patients identified as low risk by cardiologists, 75 had minor surgery and 21 had major surgery, but no clinical risk factors. In the remaining 82 patients with major surgery, ischemia and other severe abnormalities were detected in 19 (23%) patients. At follow-up, no perioperative complications occurred in minor surgery; one patient with major surgery but no clinical risk factors died from complications related to hypertrophic cardiomyopathy. Patients with at least one clinical risk factor undergoing major surgery but who did not have ischemia on stress testing (n = 63) had two complications (infarction and unstable angina). Intervention (revascularization and surgical cancellation) was probably the explanation for the absence of events in 19 patients with ischemia. With a weighted mean Medicare reimbursement (

Prognosis of patients with vascular disease after clinical evaluation and dobutamine stress echocardiography.

386), the use of a simple selection algorithm based on noncardiac surgery and clinical risk to avoid testing low-risk patients would have an average cost of

Comparison of tissue harmonic imaging with contrast (sonicated albumin) echocardiography and Doppler myocardial imaging for enhancing endocardial border resolution

214 per patient, representing a 45% savings.

New imaging technology: measurement of myocardial perfusion by contrast echocardiography

BACKGROUND Coronary disease is an important cause of long-term morbidity in patients needing major vascular surgery. We sought to assess the efficacy of preoperative clinical evaluation and the detection of inducible ischemia for prediction of immediate and long-term cardiac outcomes of patients undergoing vascular surgery. METHODS In 233 patients undergoing vascular procedures, we assessed risk clinically on the basis of Eagles criteria. Dobutamine echocardiography was performed with a standard protocol and results were classified as showing ischemia, scar, or a normal response. Patients were observed perioperatively, and late follow-up (28 +/- 13 months) was completed in all surgical survivors. A composite end point of cardiac death, myocardial infarction, and unstable and progressive angina requiring late revascularization was used to judge event-free survival. RESULTS Of 233 patients undergoing preoperative dobutamine echocardiography, 39 (17%) had inducible ischemia and 36 (15%) had scar. Perioperative events occurred in 8 patients (3%). None of the patients with ischemia had perioperative events, reflecting the effect of revascularization in 9 patients. Late events occurred in 36 patients; ischemia on preoperative stress testing was a predictor of these events even after adjusting for clinical variables and left ventricular dysfunction (relative risk = 3.3; 95% confidence interval 1.6 to 6.8; P =.001). The association of ischemia with clinical predictors was associated with incrementally worse outcome. CONCLUSION In addition to perioperative assessment, the combined use of clinical and dobutamine echocardiographic evaluation may stratify the risk of late cardiac events.

Percutaneous Transluminal Septal Reduction for Hypertrophic Obstructive Cardiomyopathy: Report from an International Pilot Study

Endocardial resolution during 2-dimensional echocardiography is technically limited in at least 10% to 15% of patients. Recently, several ultrasound imaging innovations have been introduced that may improve endocardial resolution and decrease the proportion of technically difficult studies. This study compares tissue harmonic imaging, intravenous sonicated albumin, and Doppler myocardial imaging in patients with technically difficult echocardiograms. Twenty-eight patients with known or suspected cardiac disease and poor baseline endocardial resolution were studied. Only harmonic imaging (conventional and optimized for tissue) was superior to baseline fundamental imaging (p <0.001). Harmonic imaging was superior to baseline imaging in all myocardial regions and in the majority of patients, including those with the worst baseline studies.

Impact of left ventricular outflow tract area on systolic outflow velocity in hypertrophic cardiomyopathy: A real-time three-dimensional echocardiographic study

Myocardial perfusion imaging has long been a goal for the non-invasive echocardiographic assessment of the heart. However, many factors at play in perfusion imaging have made this goal elusive. Harmonic imaging and triggered imaging with newer contrast agents have made myocardial perfusion imaging potentially practical in the very near future. The application of indicator dilution theory to the coronary circulation and bubble contrast agents is fraught with complexities and sources of error. Therefore, quantification of myocardial perfusion by non-invasive echocardiographic imaging requires further investigation in order to make this technique clinically viable.

Qualitative and quantitative effects of harmonic echocardiographic imaging on endocardial edge definition and side-lobe artifacts

Assessing the effectiveness of newer treatments for rare diseases can be challenging because of the small number of patients treated at individual centers. We enrolled patients undergoing percutaneous transluminal septal myocardial ablation (PTSMA) for hypertrophic obstructive cardiomyopathy (HOCM) at five international centers (1 Japan, 2 United Kingdom, and 2 United States). Our study group developed standard data definitions regarding clinical symptom severity, previous HOCM treatment, procedure status, and outcome, and entered patient data directly into a shared, web-based registry system. In the first 10 months of 1998, 51 patients were enrolled in our registry, with 47 ultimately receiving the PTSMA procedure. Although HOCM is consider a single disease, there were significant differences among centers in patient characteristics (age, gender, and family history of HOCM), symptom severity, diagnostic techniques (measurements taken after provocation), and treatment (amount of alcohol used, timing of injection, and number of branches attempted).