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Biomedical subjects

F A Miller

Publications and source records attributed to F A Miller.

At least 73 records · Page 4Linked to original sources
PubMed1986

Doppler color flow imaging: a new technique for visualization and characterization of the blood flow jet in mitral stenosis.

We used Doppler color flow imaging, a new noninvasive technique for mapping of intracardiac blood flow, to visualize and characterize the blood flow jet in 42 patients with mitral stenosis. Color flow imaging provides information about the direction of blood flow, its velocity, and the presence of turbulence. Although we found various jet configurations, most frequently the jet was centrally and apically directed and had a "candle flame" appearance (a central blue zone surrounded by hues of yellow and orange). The blood flow jet can be used to guide the positioning of the continuous-wave Doppler beam parallel to the blood flow; thus, the accuracy of the Doppler data can be enhanced. This new technology has promising potential for other clinical applications in cardiology.

Adult↗
PubMed1986

Objective evaluation of blunt cardiac trauma.

Serum creatine kinase isoenzyme (CK-MB) screening followed by two-dimensional echocardiography (2-DE) was used for the assessment of possible cardiac injury in victims of blunt trauma with acute thoracic or rapid deceleration injury. Of 291 victims evaluated acutely, 58 (20%) had a CK-MB fraction evident within 24 hours after injury. Sixty per cent (35/58) were diagnosed as having 'cardiac concussion' (normal 2-DE) and 40% (23/58) as having 'cardiac contusion' (abnormal 2-DE). 2-DE abnormalities most often involved the right ventricle and were characterized by dyskinesis. Only one of 35 concussion patients (3%) and nine of 23 contusion patients (39%) manifested cardiac arrhythmias within 72 hours after injury (p less than 0.006). Distinction between concussion and contusion has enabled development of a rational acute management protocol. A total of 70 patients with documented blunt cardiac injury (58 evaluated acutely, nine dead on arrival or died in the emergency room, and three delayed presentations) seen at this institution over 4 years are reported, illustrating the full spectrum of blunt cardiac injury.

Accidents, Traffic↗
PubMed1985

Echocardiographically documented mitral-valve prolapse. Long-term follow-up of 237 patients.

We determined the long-term prognosis for patients with mitral-valve prolapse documented by echocardiography by following 237 minimally symptomatic or asymptomatic patients for a mean of 6.2 years (range, 1 to 10.4). The actuarial eight-year probability of survival was 88 per cent, which is not significantly different from that for a matched control population. An initial left ventricular diastolic dimension exceeding 60 mm was the best echocardiographic predictor of the subsequent need for mitral-valve replacement (17 patients). Of the 97 patients with redundant mitral-valve leaflets identified echocardiographically, 10 (10.3 per cent) had sudden death, infective endocarditis, or a cerebral embolic event; in contrast, of the 140 patients with nonredundant valves, only 1 (0.7 per cent) had such complications (P less than 0.001). Most patients with echocardiographic evidence of mitral-valve prolapse have a benign course, but subsets at high risk for the development of progressive mitral regurgitation, sudden death, cerebral embolic events, or infective endocarditis can be identified by echocardiography.

Adolescent↗
PubMed1985

Two-dimensional echocardiographically guided pericardiocentesis: experience in 117 consecutive patients.

Pericardiocentesis guided by 2-dimensional echocardiography has been used at the Mayo Clinic since April 1980. The 2-dimensional examination localizes the pericardial fluid. Particular note is made of the place on the body wall closest to the fluid. An entry track that permits puncture of the pericardial sac without damage to any vital structure is then selected for the pericardiocentesis needle. Between April 1980 and March 1984, 132 consecutive pericardiocenteses in 117 patients were done by this technique. The volume of fluid obtained ranged from 75 to 1,700 ml (mean 650). Seventy percent of the taps were done for therapy, 21% for diagnosis, and 9% for both therapy and diagnosis. A Teflon-sheathed "intracath" needle was used to complete 80% of the pericardiocenteses. In the other 20%, a large catheter was secondarily introduced and connected to a closed drainage system. There were no deaths related to the procedure. One symptomatic pneumothorax occurred. There were 3 minor complications. Two-dimensional echocardiographic imaging of the heart and pericardial fluid permits a safe and effective means of performing pericardiocentesis.

Adolescent↗
PubMed1985

Doppler echocardiography: theory, instrumentation, technique, and application.

A Doppler examination is a valuable adjunct to a complete echocardiographic examination. It has the capability of measuring normal and abnormal velocities of blood flow noninvasively. For the first time, this procedure allows noninvasive quantitation of stenotic gradients, intracardiac pressures, and blood flow as well as semiquantitative assessment of regurgitant lesions. With this procedure, the operator must progress through a learning curve in order to gain a complete understanding of the examination techniques, the limitations of the instruments, and the Doppler physics principles before applications can be made to clinical practice. Evaluation of other aspects of Doppler echocardiography, such as color-flow mapping and assessment of diastolic events, portends great promise for the role of this procedure in the future.

Adult↗
PubMed1985

Primary cardiac tumors: experience with 30 consecutive patients since the introduction of two-dimensional echocardiography.

Experience with 30 consecutive patients who had a total of 32 primary cardiac tumors and who underwent two-dimensional echocardiographic examinations between January 1977 and June 1983 was reviewed. Most of the tumors were atrial myxomas (20 left and 4 right), and 30 were identified on echocardiography. Twenty-five patients, including 21 of 22 with atrial myxoma, underwent surgical resection on the basis of the echocardiographic examination, without preoperative angiocardiography. When the morphologic characteristics of the left atrial myxomas were studied statistically in relation to clinical abnormalities, large tumor size was most closely related to the number and type of associated clinical and laboratory abnormalities. The single exception was embolization, which correlated with echocardiographic tumor consistency. Since the introduction of two-dimensional echocardiography, the yearly incidence of cardiac tumor diagnosis at this clinic has increased several fold and the incidence of unexpected intraoperative diagnosis has been very low (one case). Echocardiography is the method of choice for clinical diagnosis. It has replaced angiocardiography for routine preoperative assessment, permits early diagnosis of cardiac neoplasms and provides insight into the pathophysiology of primary cardiac tumors.

Adolescent↗
PubMed1984

Prognostic value of predischarge 2-dimensional echocardiogram after acute myocardial infarction.

The prognostic value of a 2-dimensional echocardiogram (2-D echo) was determined in 46 patients (32 men and 14 women) who survived an acute myocardial infarction (MI) from November 1979 to December 1980. The mean age of the patients was 61 years (range 36 to 92). The MI was anterior in 21, inferior in 22 and indeterminate in 3; it was transmural in 31 and nontransmural in 15. A 2-D echo was obtained 10 to 15 days after the MI--that is, 1 to 3 days before hospital discharge. A wall motion score index (WMSI) was derived with the use of a 14-segment model of the left ventricle. Each segment was assigned a number corresponding to its wall motion (0 = hyperkinetic, 1 = normal, 2 = hypokinetic, 3 = akinetic, 4 = dyskinetic and 5 = aneurysm) and the WMSI was calculated by dividing the sum of these numbers by the number of segments visualized (1.0 = normal wall motion). During a mean follow-up of 21 months (range 15 to 28), 17 patients had a complication: death, recurrence of MI, congestive heart failure of New York Heart Association class III or IV, or angina graded New York Heart Association class III or IV. Patients with compared to those without complications had a significantly higher WMSI (2.2 +/- 0.4 and 1.7 +/- 0.5, p less than 0.005). The difference in WMSI between those who died and those who survived was not significant because of the small number of deaths.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

Shear flow characteristics of sodium hyaluronate. Relationship to performance in anterior segment surgery.

In this study, methods were developed for the in vitro evaluation of the surgical performance characteristics of viscoelastic fluids, such as sodium hyaluronate (Healon). Sodium hyaluronate exhibited superior surgical performance to chondroitin-6-sulfate. The superior performance of sodium hyaluronate resulted in part from its high viscosity, which is 20 times greater than that of chondroitin-6-sulfate at shear rates on the order of 10 s-1. The gel-like character of sodium hyaluronate as evidenced by the creep flow behavior, was greater than that of chondroitin-6-sulfate and was important for maintaining depth in the anterior chamber. It was shown that a threshold of 80 poise for the shear viscosity (at approximately 10 s-1 was needed for useful performance in surgery. It was also shown that 0.42 USP units of hyaluronidase per 1.0 mg sodium hyaluronate produces a 90% decrease in the shear viscosity (at approximately 10 s-1) within approximately 2 1/2 hours. Use of sodium hyaluronate in conjunction with hyaluronidase would allow sodium hyaluronate to remain highly viscous during surgery, but would gradually become less viscous to facilitate aqueous outflow after surgery.

Animals↗
PubMed1984

Noninvasive measurement of cardiac output by continuous-wave Doppler echocardiography: initial experience and review of the literature.

Doppler echocardiographic measurement of the velocity of blood flow in the ascending aorta is a noninvasive method for determining cardiac output in the critically ill patient. Fifty-four patients in the medical intensive care unit (35 men and 19 women, age range 41 to 91 years) in whom a Swan-Ganz catheter had been inserted underwent measurement of cardiac output with use of a commercially available continuous-wave Doppler echocardiographic instrument. The aortic root diameter was measured by A-mode echocardiography. An additional 26 patients (17 men and 9 women, age range 20 to 83 years) who had undergone an open-heart surgical procedure and had hemodynamic monitoring in the postoperative period also underwent Doppler measurement of cardiac output. In these patients, the aortic root diameter was measured directly intraoperatively. Cardiac output was also determined by thermodilution in both groups. An adequate A-mode study was possible in 83% of the medical patients but only 27% of the surgical patients. Doppler signals were adequate in 84% of the medical patients and 92% of the surgical patients. The correlation between thermodilution and Doppler-derived cardiac output was good in both the medical (r = 0.94, SEE = 0.78, P less than 0.001) and the surgical (r = 0.85, SEE = 0.78, P less than 0.001) group. Doppler echocardiography is a promising noninvasive method for determining cardiac output in critically ill patients.

Adult↗
PubMed1984

Role of two-dimensional echocardiography in the prediction of in-hospital complications after acute myocardial infarction.

To evaluate prospectively the prognostic value of two-dimensional echocardiography after acute myocardial infarction, two-dimensional echocardiography was performed on 61 consecutive patients who were admitted to the hospital with this condition. A left ventricular wall motion score index was derived from analysis of regional wall motion; an index of 2.0 or more within 12 hours of admission identified patients at high risk for pump failure, malignant ventricular arrhythmia or death. These complications occurred in 24 of 27 patients with an initial wall motion score index of 2.0 or more, but in only 6 of 34 with an initial index of less than 2.0 (p less than 0.0005). Of the 47 patients who were in Killip class I on admission, complications developed in 11 (79%) of the 14 with an initial index of 2.0 or more, but in only 6 (18%) of the 33 with an initial index of less than 2.0. After acute myocardial infarction, early determination of the wall motion score index by two-dimensional echocardiography is useful for identifying patients at high risk for complications and is especially valuable in the subset of patients who initially seem to be in stable condition as judged from clinical variables.

Aged↗
PubMed1983

Pericardiocentesis assisted by two-dimensional echocardiography.

Pericardiocentesis assisted by two-dimensional echocardiography was performed in 40 patients with effusions of various types and causes; no complications occurred. This approach combines several advantages, including visualization of the fluid-filled sac and determination of its location, estimation of the amount of fluid, and identification of structures intervening between the body surface and the pericardial sac (for example, the liver). The ideal point of needle entry caned. This approach combines several advantages, including visualization of the fluid-filled sac and determination of its location, estimation of the amount of fluid, and identification of structures intervening between the body surface and the pericardial sac (for example, the liver). The ideal point of needle entry caned. This approach combines several advantages, including visualization of the fluid-filled sac and determination of its location, estimation of the amount of fluid, and identification of structures intervening between the body surface and the pericardial sac (for example, the liver). The ideal point of needle entry can be selected to avoid contact with the heart and can be marked on the body wall. This method combines the safety and visibility of the open (surgical) approach with the simplicity of the direct ("blind") puncture method. Locating the optimal point on the body wall, closest to the pericardial fluid, allows a short, plastic-sheathed needle to be used. Pericardiocentesis by this method can be performed with ease and safety.

Adolescent↗
PubMed1982

Two-dimensional echocardiographic findings in cardiac trauma.

Cardiac contusion is a potentially fatal complication of blunt chest trauma. The diagnosis is obscured because cardiac contusion usually occurs in a setting of multisystem trauma. Furthermore, the electrocardiographic changes are nonspecific. Experience with 2-dimensional echocardiography in evaluating cardiac trauma has not previously been emphasized. This report examines the results of 2-dimensional echocardiographic examinations in 7 patients after significant blunt chest trauma. Generalized right ventricular dilatation was identified in 4 cases; superimposed segmental areas of right ventricular dilatation occurred in 3. Three patients had localized myocardial thinning, and segmental wall motion abnormalities occurred in 2. Additional abnormalities identified included ventricular thrombi (4 right and 1 left ventricular), fibrinous pericardial effusion (1), ruptured tricuspid chordae with flail leaflet (1), and a small aneurysm of the sinus of Valsalva (1). It is concluded that 2-dimensional echocardiography is useful for diagnosing cardiac contusion, for estimating the extent of myocardial damage, and for identifying accompanying cardiac lesions such as thrombi, pericardial effusion, and valvular disruption.

Adolescent↗
PubMed1982

Adverse effects of combined propranolol and chlorpromazine therapy.

The authors describe a woman with chronic schizophrenia who experienced delirium, grand mal seizure, and photosensitivity after the addition of propranolol to her neuroleptic regimen. The pharmacokinetic synergism of this combination may be hazardous for some patients.

Adult↗
PubMed1980

Permanent transvenous pacemaker implantation via the subclavian vein.

Permanent transvenous pacing with the use of a subclavian venipuncture technique was achieved in 68 patients, including 3 children. In two additional patients the subclavian vein could not be entered. The basic procedure is a modification of the Seldinger technique and involves the use of a peel-away introducer. Complications directly related to the procedure occurred in three cases. These included two pneumothoraces and one wound hematoma following puncture of the subclavian artery. All three patients were managed conservatively, without drainage. The major advantages of the subclavian venipuncture technique are that (1) it avoids extensive dissection and provides rapid access to the right ventricle via ia large-caliber vessel, (2) it allows placement of multiple catheters for atrioventricular systems, and (3) it allows the use of transvenous systems in children.

Adolescent↗
PubMed1977

Effect of a novel adenosine deaminase inhibitor (co-vidarabine, co-V) upon the antiviral activity in vitro and in vivo of vidarabine (Vira-Atm) for DNA virus replication.

A new potent inhibitor of adenosine deaminase (co-vidarabine) was used in combination studies with adenine arabinoside (vidarabine, Vira-ATM) to protect this purine nucleoside from enzymatic deamination to the more weakly active metabolite, hypoxanthine arabinoside. Comparing the combination to vidarabine alone, a significant increase (10-fold) of the antiviral activity of the combined drugs was observed against herpes and vaccinia viruses in tissue culture and subcutaneously, against cranial herpesvirus infections in mice. Several other investigators have also recently reported several-fold enhancement of vidarabine activity by newly described deaminase inhibitors. They observed that plaque formation by several large DNA-containing viruses (herpes, vaccinia, varicella zoster) and an RNA-containing oncogenic virus was markedly prevented by the combination compared to vidarabine alone. In animals, enhanced protection (increased survivors) and/or highly significant increase in the life span of dying mice treated with the 2-drug combination, was also observed compared to vidarabine administered singly. These observations in animals clearly indicate that combination studies with vidarabine (Vira-ATM) and co-vidarabine (deaminase inhibitor) deserve serious consideration as future therapy for systemic virus infections in man including herpesvirus encephalitis.

Adenosine Deaminase Inhibitors↗
PubMed1975

Disk diffusion and serial dilution tests of susceptibility of some pathogenic gram-negative bacilli and enterococci to carbenicillin and ampicillin.

Tests for susceptibility to ampicillin and carbenicillin were performed with 35 strains each of Klebsiella, Enterobacter, Serratia, and Proteus, 71 strains of Pseudomonas aeruginosa, and 68 strains of enterococci by serial dilution and disk-diffusion tests employing 10(-3) dilutions of overnight cultures as inocula for both. Commercial 10-mug ampicillin and 50- and 100-mug carbenicillin disks, and freshly prepared 10-, 50-, and 75-mug ampicillin and 10- and 50-mug carbenicillin disks were used. Results were displayed as cumulative distribution curves for both minimal inhibitory concentrations and zone diameters, and as scattergrams for correlating them. Differences in susceptibility to the two antibiotics were small for Klebsiella, Enterobacter, and Serratia and large for the others. The freshly prepared and commercial disks of the same content gave comparable zones. There was good correlation of zone diameter with each disk and the minimal inhibitory concentration. Among the ampicillin disks tested, none was useful for Pseudomonas; with the other species, the 10-mug disk, as well as those with higher ampicillin content, could discriminate susceptible from resistant strains. However, only the 75-mug disk selected some Klebsiella strains susceptible to high concentrations. The 50- and 100-mug carbenicillin disks were equally discriminating for most strains, but the higher concentration was more selective for Klebsiella. The 10-mug carbenicillin disk was as effective as the 50- and 100-mug disks for discriminating among Enterobacter, Serratia, Pseudomonas, and Proteus, but not for Klebsiella or enterococci. The 10(-3) inoculum gave zone sizes considerably larger than those reported by other workers who used the standard Kirby-Bauer method.

Ampicillin↗