Biomedical subjects

F A Miller

Publications and source records attributed to F A Miller.

At least 37 records · Page 2Linked to original sources

PubMed1998

Hypertrophic cardiomyopathy with obstruction: important diagnostic clue provided by the direction of the mitral regurgitation jet.

We present an unusual case of hypertrophic cardiomyopathy complicated by mitral regurgitation resulting from chordal rupture with flail posterior mitral leaflet. The diagnosis was suggested by the presence of an anteriorly directed mitral regurgitation jet on transthoracic color flow imaging, in addition to the typical posterolateral-lateral jet caused by systolic anterior mitral motion. The flail posterior leaflet was confirmed by transesophageal echocardiography, and the patient underwent mitral valve repair in addition to myectomy. This combination of hypertrophic cardiomyopathy and flail mitral leaflet usually requires surgical intervention, and prompt diagnosis is important. The presence of an anteriorly directed mitral regurgitant jet should always raise suspicion of posterior mitral leaflet abnormality.

Cardiomyopathy, Hypertrophic↗

PubMed1998

Retained left atrial catheter: an unusual cardiac source of embolism identified by transesophageal echocardiography.

Embolic events have become a major indication for transesophageal echocardiography. We report three patients with cerebrovascular accident who were discovered to have retained left atrial catheter as a cardiac source of embolism. These radiolucent catheters, placed during previous cardiac surgery, were used for perioperative left atrial monitoring. Fracture of the catheter occurred during percutaneous removal after surgery. Subsequent identification was established by transesophageal echocardiography, which demonstrated a characteristic appearance of the catheter remnant within the left atrium. All patients underwent reoperation to remove the retained catheter and have had no recurrent embolic events. Although uncommon, retained catheter in the left atrium is an important potential source of systemic embolism. The diagnosis can be easily made with transesophageal echocardiography and should prompt surgical extraction of the catheter.

Aged↗

PubMed1998

Teardrop sign: echocardiographic features in cardiac herniation.

Cardiac herniation through an acquired pericardial defect is potentially fatal. Typically, symptoms manifest within days of a surgical procedure. We describe a patient with late ventricular herniation after surgical formation of an apical pericardial window.

Adult↗

PubMed1998

Aneurysms in the left ventricular outflow tract: clinical presentation, causes, and echocardiographic features.

We present a descriptive compendium of anatomically interrelated aneurysms and aneurysmal-like structures arising in and around the left ventricular outflow tract. Images selected from the Mayo Clinic echocardiography database illustrate classic or typical examples of each entity. Essential morphologic features of each lesion are described. Clinical presentation, causes, and diagnostic echocardiographic features taken together can improve recognition and clinical management of this diverse group of anomalies.

Aortic Aneurysm↗

PubMed1997

Hemodynamic performance of small aortic valve bioprostheses: is there a difference?

BACKGROUND: There is the potential for left ventricular outflow obstruction when small aortic valve bioprostheses are employed in normal-sized or large adults. It has been hoped that bovine pericardial valves would improve hemodynamic performance in the smaller tissue valve sizes. METHODS: To determine in vivo hemodynamic performance of heterograft aortic valve prostheses, we analyzed echocardiographic data from patients receiving 21- or 23-mm Carpentier-Edwards pericardial, Medtronic Intact, and Carpentier-Edwards porcine bioprostheses. In addition, data from 19-mm Carpentier-Edwards pericardial valves were included for comparison of hemodynamic performance between valve sizes. Doppler echocardiography was performed in 151 patients within 2 weeks of operation. Left ventricular outflow gradient was derived from continuous Doppler measurements of flow velocity, and effective orifice area was calculated by the continuity equation. RESULTS: There were statistically significant differences in hemodynamic performance of different sized prostheses for each valve type (effective orifice area, p < 0.01; valvular gradient, p < 0.03). There were, however, no significant differences in effective orifice area or mean gradient for different valve types within each size category. CONCLUSIONS: The in vivo hemodynamic performance of these three different aortic valve heterograft bioprostheses is similar. Patient-prosthesis mismatch with heterograft prostheses, as demonstrated by the indexed effective orifice area can be avoided by appropriate sizing and use of annular enlarging techniques when necessary.

Adult↗

PubMed1997

Eosinophilic myocarditis manifesting as myocardial infarction: early diagnosis and successful treatment.

OBJECTIVE: To report a case of eosinophilic myocarditis with remarkable initial clinical manifestations and outcome. MATERIAL AND METHODS: A 67-year-old woman with hypertension and a history of asthma and drug hypersensitivity was referred to our institution with a diagnosis of acute myocardial infarction on the basis of severe chest pain, ST elevation on an electrocardiogram, and a slight increase in cardiac enzymes. Further diagnostic studies were performed. RESULTS: Echocardiography disclosed left ventricular dysfunction in conjunction with apical asynergy, thinning, and thrombus. The eosinophil count in the peripheral blood was increased only slightly. Coronary angiography showed normal arteries and prompted the performance of endomyocardial biopsy, which revealed active eosinophilic myocarditis. After corticosteroid therapy, global and regional left ventricular function returned to normal. CONCLUSION: This unusual clinical picture and outcome demonstrate that eosinophilic myocarditis may simulate acute myocardial infarction and should be considered in patients with a history of allergies or acute left ventricular dysfunction, even in the absence of pronounced eosinophilia in the peripheral blood. With appropriate medical therapy, recovery for these patients can be complete.

Acute Disease↗

PubMed1996

Comparison of techniques for implantation of aortic valve allografts.

BACKGROUND: Various implantation techniques for allograft aortic valve replacement have evolved over the years. Our objective was to examine the effects of different implantation methods on subsequent valve performance and durability. METHODS: Between May 1985 and January 1994, 137 patients underwent allograft aortic valve replacement. The first 59 aortic valve allografts were inserted by the freehand scalloped technique with removal of the aortic sinuses, and the last 78 valves were inserted by the cylinder technique, in which the aortic sinuses and sinotubular junction were retained. The mean age of the 91 men and 46 women was 53.7 years (range, 18 to 83 years). Preoperative diagnoses were aortic stenosis (n = 57), aortic regurgitation (AR, n = 40) and aortic stenosis/AR (n = 40); 27 patients had prior aortic valve operations and 1 patient had a previous heart transplantation. Active endocarditis was present in 29 patients. Associated procedures included coronary artery bypass (n = 33), ascending aneurysm repair (n = 4), left ventricular aneurysmectomy (n = 3), repair of atrial septal defect (n = 2), mitral valve repair or replacement (n = 6), and aortic root enlargement (n = 24). Follow-up was complete in 133 patients (97%) a mean of 4.9 years (range, 1 day to 9.8 years) after allograft aortic valve replacement. RESULTS: Operative mortality was 6.5% for all patients but only 1.9% for patients without infection having isolated aortic valve replacement. Early echocardiography (mean of 8.4 days postoperatively) demonstrated no AR or mild AR and a mean gradient of 10.6 +/- 6.2 mm Hg in all patients. The cumulative risk of development of grade III or IV AR at 7 years postoperatively was 26.2% +/- 6.3% in the scallop group and 12.4% +/- 5.6% in the cylinder group (p = 0.4). Late postoperatively, transvalvular gradient by echocardiography was 13.1 +/- 9.4 mm Hg, and was similar in the two study groups. Late AR led to reoperation in 13 patients (22%) who had initial implantation with the scallop method and only 4 patients (5.4%) who had the valve inserted with the cylinder method. However, because duration of follow-up was longer for patients in the scallop group, cumulative risk of reoperation was similar at 5 years postoperatively (scallop, 13.7% [95% confidence interval, 76.7% to 95.8%]; cylinder, 11.5% [95% confidence interval, 75.5% to 99.1%]). CONCLUSIONS: The insertion of an aortic valve allograft as a cylinder, retaining the sinotubular junction, appears to result in less aortic regurgitation at 7 years postoperatively, and with additional follow-up may result in less reoperation for AR.

Adolescent↗

PubMed1996

Valve replacement in aortic stenosis with preoperative mean gradient < 50 mmHg: hemodynamic outcome.

BACKGROUND AND AIMS OF THE STUDY: No prior studies have defined pre- versus postoperative hemodynamics of large numbers of patients with low mean transvalvular gradients. This was our objective. METHODS: Retrospective analysis was undertaken of preoperative and postoperative echo/Doppler data in 294 patients who underwent aortic valve replacement (AVR) for aortic stenosis (AS). Some 136 patients had a preoperative mean gradient of < 50 mmHg. The relationship of preoperative to pre- minus postoperative (delta) mean gradient (GRAD), peak valvular velocity (V2), left ventricular outflow tract velocity (V1), V1/V2 ratio, V2-V1, and aortic valve area (AVA) were plotted and analyzed such that a 'zero-benefit threshold' from surgery could be estimated. RESULTS: Strong relationships (r > 0.80) were noted for GRAD to delta GRAD, V2 to delta V2, and (V2-V1) to delta (V2-V1) with zero-benefit thresholds of 16 mmHg for GRAD, 2.6 m/s for V2 and 1.7 m/s for V2-V1. These thresholds were lower in patients who received homografts (11 mmHg, 2.2 m/s, and 1.1 m/s respectively), p < 0.02. The relationship of pre operative V1/V2 to delta V1/V2 and AVA-delta AVA were weaker (r = 0.52 and 0.33 respectively) with zero-benefit thresholds of 0.41 and 2.0 cm2. Among patients with depressed preoperative fractional shortening, improvement was confined to those without coexistent coronary artery disease. CONCLUSION: This analysis of thresholds of mean gradient benefit suggests that most patients with low gradient AS improve hemodynamically from AVR. The hemodynamic 'break-even' point averages a mean gradient of 16 mmHg.

Aged↗

PubMed1995

Effective mitral regurgitant orifice area: clinical use and pitfalls of the proximal isovelocity surface area method.

OBJECTIVES: We attempted to determine the accuracy and pitfalls of calculating the mitral regurgitant orifice area with the proximal isovelocity surface area method in a clinical series that included patients with valvular prolapse and eccentric jets. BACKGROUND: The effective regurgitant orifice area, a measure of lesion severity of mitral regurgitation, can be calculated by the proximal isovelocity surface area method, the accuracy and pitfalls of which have not been established. METHODS: In 119 consecutive patients with isolated mitral regurgitation, effective regurgitant orifice area was measured by the proximal isovelocity surface area method and compared with measurements simultaneously obtained by quantitative Doppler and quantitative two-dimensional echocardiography. RESULTS: The effective mitral regurgitant orifice area measured by the proximal isovelocity surface area method tended to be overestimated compared with that measured by quantitative Doppler and quantitative two-dimensional echocardiography (38 +/- 39 vs. 36 +/- 33 mm2 [p = 0.09] and 34 +/- 32 mm2 [p = 0.02], respectively). Overestimation was limited to patients with prolapse (61 +/- 43 vs. 56 +/- 35 mm2 [p = 0.05] and 54 +/- 34 mm2 [p = 0.014]) and was restricted to patients with nonoptimal flow convergence (n = 7; 137 +/- 35 vs. 84 +/- 34 mm2 [p = 0.002] and 79 +/- 33 mm2 [p = 0.002]). In patients with optimal flow convergence (n = 112), excellent correlations with both reference methods were obtained (r = 0.97, SEE 6 mm2 and r = 0.97, SEE 7 mm2, p < 0.0001). CONCLUSIONS: In calculating the mitral effective regurgitant orifice area with the proximal isovelocity surface area method, the observed pitfall (overestimation due to nonoptimal flow convergence) is rare. Otherwise, the method is reliable and can be used clinically in large numbers of patients.

Aged↗

PubMed1995

Stress echocardiography. Part I. Exercise echocardiography: techniques, implementation, clinical applications, and correlations.

OBJECTIVE: To describe the techniques and applications of exercise echocardiography. DESIGN: We review pertinent experimental and clinical studies from the literature and present our experience with the first 2,000 patients who underwent exercise echocardiography in our laboratory. MATERIAL AND METHODS: The indications for and contraindications to exercise echocardiography and the advantages, limitations, and accuracy of this procedure in comparison with other techniques for detecting coronary artery disease are discussed. RESULTS: Exercise echocardiography is increasingly used for the noninvasive evaluation of coronary artery disease because, in addition to its diagnostic capabilities, it offers attractive features such as portability, versatility, rapid availability of results, and relatively low cost. For accurate interpretation of the results, the workload achieved and the time between completion of exercise and image acquisition must be considered. The major limitation of exercise echocardiography is the high degree of operator dependence. For accurate interpretation of regional wall motion abnormalities and recognition of ischemic changes, specific training and extensive experience are necessary. CONCLUSION: Although exercise echocardiography has only relatively recently become a widely used technique, it has proved to have considerable accuracy in the diagnosis of coronary artery disease (mean sensitivity, 84%; mean specificity, 87%). In high-volume laboratories, feasibility studies have shown success rates between 90 and 99%; thus far, reproducibility has been satisfactory. Other applications of exercise echocardiography being studied are follow-up monitoring after revascularization, determination of prognosis, and assessment of valvular heart disease.

Contraindications↗

PubMed1995

Stress echocardiography. Part II. Dobutamine stress echocardiography: techniques, implementation, clinical applications, and correlations.

OBJECTIVE: To describe the rationale, methods, and clinical applications for dobutamine stress echocardiography. DESIGN: We review our experience with the first 1,000 Mayo Clinic patients who underwent this procedure and discuss studies from the literature that have assessed the accuracy of dobutamine stress echocardiography in determining the presence and extent of coronary artery disease. MATERIAL AND METHODS: The Mayo protocol for dobutamine stress echocardiography is presented, and the indications for use of this test and comparisons of sensitivity and specificity with other tests are summarized. RESULTS: Although exercise stress testing is the usual noninvasive method for the detection and assessment of coronary artery disease, a substantial number of patients are unable to perform adequate exercise because of physical limitations. In these patients, dobutamine stress echocardiography has emerged as a feasible, safe, and accurate method for the evaluation of coronary artery disease. The test has been proved to be valuable in the noninvasive diagnosis of coronary artery disease and to have an accuracy comparable to that of tomographic perfusion imaging. Other indications for dobutamine stress echocardiography include risk stratification before noncardiac surgical procedures, risk stratification after myocardial infarction, and identification of viable myocardium in patients with left ventricular dysfunction. CONCLUSION: Dobutamine stress echocardiography is an accurate, safe, cost-effective, and portable procedure for the noninvasive diagnosis of coronary artery disease and for the preoperative assessment of patients with such disease, especially those who are unable to perform adequate exercise tests.

Adult↗

PubMed1995

Role of transesophageal echocardiography in hemodynamically unstable patients.

OBJECTIVE: To evaluate the clinical impact of transesophageal echocardiography on subsequent management and outcome in hemodynamically unstable patients with suspected cardiovascular pathologic conditions. DESIGN: We reviewed data on patients with hemodynamic instability (hypotension, shock, or pulmonary edema) who underwent transesophageal echocardiography between December 1987 and May 1994. MATERIAL AND METHODS: A total of 127 patients (70 male and 57 female patients with a mean age of 68 years) underwent transesophageal echocardiography at our institution as part of the diagnostic procedures used to evaluate unstable hemodynamics. RESULTS: No clinically significant complication was encountered during the procedure; transesophageal echocardiographic imaging was inadequate in three patients (2%). Of the 124 patients with adequate images, transesophageal echocardiography disclosed a severe cardiovascular abnormality responsible for the unstable hemodynamics in 65 patients (52%), and 26 patients (21%) underwent urgent pericardiocentesis or a cardiac surgical procedure, primarily based on transesophageal echocardiographic findings. CONCLUSION: Transesophageal echocardiography can be safely performed in hemodynamically unstable patients, it produces a high diagnostic yield, and it provides important information for prompt therapeutic decision making. Therefore, we recommend transesophageal echocardiography as one of the initial diagnostic procedures in critically ill patients suspected of having an underlying cardiovascular disorder.

Aged↗

PubMed1995

Cardiac echinococcosis: case report of unusual echocardiographic appearance.

An unusual echocardiographic appearance of a cardiac echinococcal lesion confirmed intraoperatively is described in a patient with nonspecific cardiac complaints. Although previous reports have emphasized the echolucent, often multiseptated nature of echinococcal lesions, such characteristics were absent in this case. Thus, in the appropriate clinical setting, echinococcal infection should be included in the differential diagnosis of solid mass lesions of the heart because the surgical approach may need to be altered.

Adult↗

PubMed1994

Circulating heart autoantibodies in familial as compared with nonfamilial idiopathic dilated cardiomyopathy.

BACKGROUND: Idiopathic dilated cardiomyopathy (DCM) is a serious heart disease characterized by enlargement of one or both ventricles and ventricular dysfunction. Although most patients have sporadic disease, 20% have been found to have familial DCM when relatives are investigated by echocardiography. No other factors have been identified to date that consistently distinguish familial from nonfamilial DCM. Although some patients have a family history of DCM, a "negative" family history does not exclude familial DCM because affected family members may be presymptomatic or undiagnosed. Because some patients have life-threatening complications at the time of initial assessment of DCM, identifying a serum marker predictive of familial disease would help determine which families would most likely benefit from echocardiographic investigation. OBJECTIVE: In this study, our objective was to determine whether antiheart autoantibodies could be used to distinguish familial from nonfamilial idiopathic DCM. METHODS: We analyzed serum specimens for antiheart antibodies from 19 patients categorized as having familial DCM and 15 classified as having nonfamilial DCM on the basis of echocardiographic investigation of first-degree relatives. The mean duration of disease in these 34 patients was 50 months at the time the serum specimens were obtained. RESULTS: Titers of antibodies against the adenine nucleotide translocator, branched-chain keto acid dehydrogenase, and cardiac myosin did not distinguish between familial and nonfamilial cases of DCM.

3-Methyl-2-Oxobutanoate Dehydrogenase (Lipoamide)↗

PubMed1994

Traumatic tricuspid valve insufficiency. Experience in thirteen patients.

From 1964 through June 1993, thirteen patients with traumatic tricuspid insufficiency were treated surgically; all were male, and the ages ranged from 17 to 64 years (median 39 years). The condition was associated with blunt chest trauma in all patients: motor vehicle accidents in twelve and an explosion of a tank of compressed air in one. The median duration between trauma and operation was 17 years (range 1 month to 37 years). Preoperatively, six patients were in sinus rhythm and seven were in atrial fibrillation. At operation, the right ventricular function appeared moderately to severely depressed in twelve patients. In twelve patients, the anterior leaflet was flail because of chordal rupture (n = 9), rupture of anterior papillary muscle (n = 3), or tear in the anterior leaflet (n = 1). In one patient, the septal leaflet was missing and in another it was retracted and adherent to the ventricular septum. In five patients the tricuspid valve was repaired and in eight it was replaced. In seven patients in the latter group, the chordae, papillary muscles, and/or tricuspid valve leaflet(s) were found to be in a contracted and atrophic state, precluding repair. No early or late deaths occurred. At follow-up extending to 26 years (median 12 years), 12 patients are in New York Heart Association class I and one patient is in class II. Nine patients were in sinus rhythm and four were in atrial fibrillation. Although our experience indicates that good functional results can still be achieved many years after the onset of traumatic tricuspid valve insufficiency, earlier diagnosis and surgical treatment should increase the feasibility of tricuspid valve insufficiency, earlier diagnosis and surgical treatment should increase the feasibility of tricuspid valve repair, prevent progressive deterioration of right ventricular function, and increase the possibility of maintaining late sinus rhythm in a greater number of patients.

Accidents, Traffic↗

PubMed1994

Early clinical and hemodynamic evaluation of the aortic intact porcine bioprosthesis.

Between October 1990 and June 1992, 89 patients underwent aortic valve replacement using the Intact porcine bioprosthesis. Their mean age (+/- SD) was 74.6 +/- 7.8 years (range 48 to 92). Seventy-five percent were in NYHA Class III-IV, 79 (89%) had AS or AS/AI, 10 (11%) had had previous cardiac surgery and 25 (32%) had an EF < 0.50. Associated procedures included CABG 45 (51%), septal myectomy 13 (15%), annular enlargement eight (9%), LV aneurysmectomy one, ascending aortic replacement one, and arch replacement one. Hospital mortality was four (4.5%). Hemodynamics were assessed with 2D echo with Doppler at seven days, six weeks and 12 months, and compared with 130 standard Carpentier-Edwards (C-E) porcine bioprostheses. At follow up, two patients have 2/4 perivalvular AI. The transvalvular gradients for the Intact valve were as follows: 21 mm-16.9 +/- 7.4 mmHg; 23 mm-18.9 +/- 6.2 mmHg; 25 mm-17.1 +/- 5.4 mmHg; 27 mm-15.0 +/- 3.7 mmHg; and 29 mm-15.0 +/- 2.1 mmHg. When compared to the standard Carpentier-Edwards porcine bioprostheses, the 21 mm Intact valve had the same gradient as the C-E prosthesis. However, the transvalvular gradients were slightly higher for the Intact valve for sizes 23-29 mm when compared to the corresponding C-E valve. The effective orifice area and effective orifice area index was no different between the two valves. Satisfactory hemodynamics are seen in the smaller prostheses when valves are matched for BSA and when aortic annular enlargement is performed when necessary.

Aged↗

PubMed1993

Multiplane transesophageal echocardiography: image orientation, examination technique, anatomic correlations, and clinical applications.

Multiplane transesophageal echocardiography (TEE) consists of a single ultrasound array or imaging sector that can be rotated around the long axis of the ultrasound beam typically in a 180 degrees arc. This capability produces a circular (conical) continuum of tomographic two-dimensional images. The principal advantage of multiple TEE is that the transducer can be rotated to an image-specific orientation and critically optimized. Thus, manipulation of the transducer is less complex than with the biplane technique, and user adaptation is considerably enhanced. The logical image notation (that is, degrees of rotation) and orientation are described in this report. A step-by-step approach to the multiplane TEE examination, which evolved from our initial experience with 400 consecutive patients, is correlated with accompanying tomographic anatomic corroboration. The unique clinical applications are discussed and related to the amplification of diagnostic information. Although the multiplanar TEE transducer is relatively large, all adult patients who weigh 40 kg or more can be examined. No major complications occurred in our initial experience with this promising new technology.

Adolescent↗

PubMed1993

Dystrophin analysis in idiopathic dilated cardiomyopathy.

Idiopathic dilated cardiomyopathy (DCM) is characterised by ventricular dilatation and impaired systolic function resulting in congestive heart failure and frequently death. A dilated cardiomyopathy is common in patients with symptomatic Duchenne/Becker muscular dystrophy, a disease caused by dystrophin gene defects. However, cardiomyopathy is rarely the predominant clinical feature of this form of muscular dystrophy. To determine whether dystrophin gene defects might account for a significant number of patients with apparently isolated idiopathic DCM, we performed dystrophin gene analysis in 27 DCM patients, who were ascertained as part of a prospective study on idiopathic DCM. No dystrophin gene defects were found in our patients, whose average age was 50 years. These data suggest that dystrophin defects are not a common cause of idiopathic DCM in this age group in the absence of skeletal muscle cramps or weakness.

Blotting, Southern↗