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R A Nishimura

Publications and source records attributed to R A Nishimura.

At least 145 records · Page 8Linked to original sources
PubMed1987

Comparison of monoplane and biplane assessment of regional left ventricular wall motion after thrombolytic therapy for acute myocardial infarction.

Regional left ventricular (LV) function was assessed using serial biplane orthogonal LV angiograms recorded before and after reperfusion therapy for acute myocardial infarction (AMI) in 24 patients. Improvement in regional LV function was seen in only 5 patients after reperfusion therapy when only the right anterior oblique view was analyzed; improvement in regional wall motion was seen in 14 when biplane views were analyzed. Biplane analysis was particularly important in the 12 patients with right coronary artery occlusion, among whom the right anterior oblique view showed improvement in only 1 patient but the left anterior oblique view showed improvement in 6 patients (p less than 0.05). Biplane analysis is more sensitive than monoplane right anterior oblique analysis alone for detecting improvement in LV function after reperfusion therapy for AMI. However, both views are complementary, adding information about regional function not revealed by either view alone.

Female↗
PubMed1987

Severe isolated tricuspid insufficiency in coronary artery disease.

We describe 3 patients who presented with severe cardiac disability as a result of tricuspid insufficiency, in the setting of severe coronary disease. Pertinent physical findings were signs of right heart failure, a tricuspid regurgitant murmur, and absence of left heart failure. Echocardiography and subsequent cardiac catheterization demonstrated significant tricuspid insufficiency, dilated right ventricle, impairment of right ventricular function, and preserved left ventricular function. Two patients were treated successfully with DeVega annuloplasty. Symptomatic tricuspid insufficiency can be seen in the setting of coronary artery disease and, when left ventricular function is well preserved, surgical correction is feasible.

Aged↗
PubMed1987

Cardiomyopathy in patients with hereditary motor and sensory neuropathy.

Twelve affected persons in the third decade of life or later, and the 14 nearest age- and sex-matched unaffected relatives, of a large kindred with autosomal dominant hereditary motor and sensory neuropathy not linked to the Duffy blood group (HMSN type IA) were assessed for arrhythmia and cardiomyopathy. Cardiac abnormalities were no more frequent in the affected persons than in the unaffected relatives. The heart of a patient with HMSN type II who had died of complications of cardiomyopathy was found to have rheumatic disease-type myocarditis with Aschoff bodies. The results of this study provide further evidence against an association of cardiomyopathy and HMSN.

Adult↗
PubMed1987

Assessment of myocardial perfusion by videodensitometry in the canine model.

Assessment of the functional severity of coronary stenoses has become increasingly important as the intrinsic limitations of coronary angiography have been documented. Videodensitometric coronary flow reserve has been proposed as a means to assess the physiologic significance of a coronary stenosis in humans. This study compared videodensitometric assessment of coronary flow with microsphere quantitation in the closed chest canine model. In five dogs, flow rates were assessed at baseline, after vasodilation with adenosine, after vasoconstriction with vasopressin and during rapid cardiac pacing. The videodensitometric peak density, time to one-half peak density and washout time (time from peak to one-half peak density) were compared at each flow state with flow assessed by microsphere injection. Reproducibility of videodensitometric measurements from two different coronary injections during the same flow state was best with peak density (r = 0.94). Videodensitometric flow ratios (flow state under study to flow at rest) using peak density demonstrated a fair correlation with flow ratios by microsphere (r = 0.81). There was poor correlation between flow ratios when time to one-half peak or washout time was used. Videodensitometric flow measurements used in vivo to assess a wide range of drug-induced coronary flows may not accurately reflect coronary flow measured by microsphere.

Adenosine↗
PubMed1987

Evaluation of intraoperative transesophageal two-dimensional echocardiography.

Transesophageal two-dimensional echocardiography (TEE) was evaluated in 11 patients who underwent myocardial revascularization. The TEE transducer was positioned to view the left ventricular (LV) short-axis at the level of the papillary muscles (midcavity). Good quality echocardiographic images were obtainable in ten of 11 patients. Global LV function was assessed by measuring LV end-diastolic and end-systolic area and computing the fractional area change (FAC). Measurements of LV areas and FAC had excellent intraobserver reproducibility. Regional LV function was analyzed in two ways after dividing the short-axis view of the LV into four or five anatomic segments. Systolic wall thickening (SWT) of the myocardium was measured in each of four segments by digitization of the endocardial and epicardial borders of the LV and determining the fractional wall thickening. Measurements of SWT were not reproducible, primarily because of a difficulty in delineating the epicardial border of the LV accurately. In the second method, regional wall motion (RWM) in each of five segments was graded according to a previously developed scoring system. RWM analysis proved to be a measurement with excellent interobserver and intraobserver reproducibility. TEE was performed without complication and found to be a reproducible method for assessing global and regional LV function. Quantitative analysis is tedious and, therefore, currently not available on-line in the operating room.

Echocardiography↗
PubMed1987

To anticoagulate or not: implications for the management of patients with acute myocardial infarction complicated by both left ventricular thrombus and pericardial effusion.

We reviewed the clinical and echocardiographic characteristics of seven patients with left ventricular thrombus and pericardial effusion. Each patient had a recent anterior wall myocardial infarction with an apical left ventricular thrombus. Two patients had clinical evidence of pericarditis. On two-dimensional echocardiography, the effusion was judged to be small in five cases and moderate in two. All patients received parenteral heparin therapy; six of the seven patients subsequently received long-term oral anticoagulation therapy. None of the patients had any clinical or two-dimensional echocardiographic evidence of increasing pericardial effusion or tamponade. Documented systemic embolization was seen in only one patient, whose anticoagulant therapy was stopped 2 weeks after myocardial infarction. In five patients, repeat two-dimensional echocardiography was performed from 2 to 4 months after infarction; in four patients, neither pericardial effusion nor left ventricular thrombus was found. In this group of patients, both short- and long-term anticoagulants were safely administered despite pericardial effusion.

Aged↗
PubMed1986

Early repair of mechanical complications after acute myocardial infarction.

Acute mitral regurgitation and ventricular septal defect after myocardial infarction are devastating complications with high mortality. Surgical intervention is warranted for these entities, but the timing of operation remains controversial. In a previous retrospective study of patients with acute mitral regurgitation, we concluded that early emergency operation be undertaken. We describe nine patients subsequently seen at the Mayo Clinic (seven with acute mitral regurgitation and two with acute ventricular septal defect) who underwent emergency operation within four days of evaluation. Four patients were operated on within four hours after the onset of their complications. All patients survived the perioperative period. Eight of nine are alive and well over a mean follow-up period of 9.7 months. We recommend early surgical repair of mechanical complications after acute myocardial infarction.

Adult↗
PubMed1986

The Valsalva maneuver and response revisited.

The Valsalva maneuver is a time-honored technique that is commonly used at the bedside for the evaluation of heart murmurs. It is also a valuable adjunct in the evaluation of left ventricular function and autonomic dysfunction. In this article, we describe the normal and abnormal responses to the Valsalva maneuver and provide insight into the underlying hemodynamics in conditions that provoke an abnormal response.

Blood Pressure↗
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

Evaluation of hypertrophic cardiomyopathy by Doppler color flow imaging: initial observations.

We evaluated hypertrophic cardiomyopathy in 12 patients by Doppler color flow imaging and continuous-wave Doppler echocardiography. Mitral regurgitation was detected by continuous-wave Doppler echocardiography in eight patients and was related to the degree of systolic anterior motion of the mitral valve. Adequate color flow images were obtained in 10 of the 12 patients, and mitral regurgitation was demonstrated in 6. A qualitative and quantitative analysis of the color flow imaging revealed a temporal pattern in the left ventricular outflow tract that consisted of normal-velocity laminar flow during early systole followed by turbulent flow in midsystole. The maximal amount of mitral regurgitation on color flow imaging occurred late in systole, after the appearance of turbulent flow in the left ventricular outflow tract. Of the 12 patients, 10 had late-peaking continuous-wave Doppler velocity profiles in the left ventricular outflow tract. The peak velocity detected in the left ventricular outflow tract was positively correlated with the degree of systolic anterior motion of the mitral valve. Patients with higher peak velocities in the left ventricular outflow tract had prolonged ejection times. These findings on Doppler echocardiography support the concept of left ventricular outflow obstruction in some patients with hypertrophic cardiomyopathy.

Adult↗
PubMed1986

Aortic dissection with fistula to right atrium. Noninvasive diagnosis by two-dimensional and Doppler echocardiography with successful repair. Case report and review of the literature.

Aortic dissection with rupture into the right atrium is rare, and a high index of suspicion is required for its clinical recognition. The diagnosis should be considered in a patient with chest pain or dyspnea who at presentation has a widened pulse pressure, a continuous murmur, and evidence of right ventricular volume overload, especially when there is a history of a previous cardiac operation. Two-dimensional and Doppler echocardiography can establish the diagnosis and permit early surgical repair of the dissection and fistula.

Aged↗
PubMed1986

Measurement of intracardiac pressures. State of the art--1986.

With Doppler echocardiography, through assessment of the velocity profile of flow in the region of stenoses, regurgitant lesions or shunts the pressure difference between two cardiac chambers or a cardiac chamber and great vessel can be calculated, using the Bernoulli equation. If the pressure in one chamber is known from clinical parameters, then the pressure in the second chamber can be estimated. In stenosis of the left ventricular outflow tract, the left ventricular systolic pressure can be calculated as the sum of the pressure difference between the left ventricle and aorta during systole and the cuff blood pressure. In right ventricular outflow tract obstruction, the velocity of blood flow can be used to derive the pressure gradient between the right ventricle and pulmonary artery during systole and, if the right ventricular systolic pressure is known, the pulmonary artery pressure can be estimated. This method is applicable in valvular and supravalvular stenoses, as well as for pulmonary artery bands or right ventricular-pulmonary artery conduits. If the right atrial pressure is known or estimated clinically as the jugular venous pressure, the right ventricular systolic pressure can be calculated; in the absence of right ventricular outflow tract obstruction from the velocity of a tricuspid regurgitation jet, this will approximate pulmonary artery systolic pressure. Further parameters for evaluation of pulmonary artery pressure are the isovolumetric right ventricular relaxation time or the relaxation time index (Burstin method) and the preejection period, acceleration time and right ventricular ejection time as derived from the pulmonary artery velocity profile.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Flow Velocity↗
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

Constrictive pericarditis: assessment of current diagnostic procedures.

Constrictive pericarditis frequently poses a diagnostic challenge because of its varied manifestations. Accurate diagnosis is essential, however, because surgical decortication may yield excellent clinical results. Although new diagnostic procedures have helped the clinician to diagnose constrictive pericarditis, the initial clinical suspicion of this diagnosis must be high for appropriate interpretation of these tests. Echocardiography is useful, primarily for distinguishing various other cardiac abnormalities that may simulate constrictive pericarditis. Computed tomography is a valuable procedure for assessment of pericardial thickening. In addition, evaluation of early diastolic filling by computerized digitization in conjunction with echocardiography, angiography, and invasive hemodynamics shows promise as a diagnostic tool. Even with these new diagnostic aids, distinguishing constrictive pericarditis from restrictive cardiomyopathy may be difficult and, in some cases, may necessitate an exploratory operative procedure.

Aged↗