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Biomedical subjects

B W Usher

Publications and source records attributed to B W Usher.

At least 19 recordsLinked to original sources
PubMed1992

Cardiovascular status of panic disorder patients with and without prominent cardiac symptoms.

The extent of the cardiovascular evaluation of panic disorder patients with cardiac symptoms remains a dilemma for the clinician. The authors conducted a pilot study to assess the cardiac status of 20 panic disorder patients, 10 of whom had prominent cardiac symptoms and 10 of whom did not. No differences in the cardiac abnormalities were found between the groups. These findings suggest that panic disorder patients with cardiac symptoms are not more likely to have cardiac disease than those without prominent cardiac symptoms. The practical implications of these findings are discussed.

Adult↗
PubMed1992

Mitral valve replacement with and without chordal preservation in patients with chronic mitral regurgitation. Mechanisms for differences in postoperative ejection performance.

BACKGROUND: Standard mitral valve replacement (MVR) in patients with chronic mitral regurgitation consistently results in a decrease in postoperative left ventricular (LV) ejection performance. This fall in ejection performance has been attributed, at least in part, to unfavorable loading conditions imposed by the elimination of the low-impedance pathway for LV emptying into the left atrium. In contrast to standard MVR in which the chordae tendineae are severed, however, MVR with chordal preservation (MVR-CP) does not usually decrease LV ejection performance despite similar removal of the low-impedance pathway. The purpose of the present study was to define the mechanisms responsible for this discordance in postoperative ejection performance between MVR with and without chordal preservation. METHODS AND RESULTS: Echocardiography and sphygmomanometer blood pressures were obtained in 15 patients with pure chronic mitral regurgitation before and 7-10 days after mitral valve surgery. These measurements were used to calculate ventricular volume, wall stress, and ejection fraction. Seven patients underwent MVR with chordal transection (MVR-CT), and eight patients underwent MVR-CP. MVR-CT resulted in no postoperative change in LV end-diastolic volume, a significant increase in LV end-systolic volume, a significant increase in end-systolic stress, from 89 +/- 9 to 111 +/- 12 g/cm2 (p < 0.05), and a significant decrease in ejection fraction, from 0.60 +/- 0.02 to 36 +/- 0.02 (p < 0.05). In contrast, patients who underwent MVR-CP had a significant decrease in LV end-diastolic and end-systolic volumes. End-systolic wall stress actually fell from 95 +/- 6 to 66 +/- 6 g/cm2 (p < 0.05), and ejection fraction was unchanged (0.63 +/- 0.01 before and 0.61 +/- 0.02 after mitral valve surgery) instead of reduced. CONCLUSIONS: MVR-CT resulted in a decrease in ejection performance caused in part by an increase in end-systolic stress, which in turn increased end-systolic volume. Conversely, MVR-CP resulted in a smaller LV size, allowing a reduced end-systolic stress and preservation of ejection performance despite closure of the low-impedance left atrial ejection pathway.

Chordae Tendineae↗
PubMed1990

The fractional shortening-velocity ratio: validation of a new echocardiographic Doppler method for identifying patients with significant aortic stenosis.

Previous studies have shown that Doppler echocardiographic methods based on the continuity equation can accurately determine aortic valve area in patients with clinically significant aortic stenosis; nonetheless, methods based on the continuity equation are time-consuming and may not be technically possible in all subsets of patients. The purpose of this study was to develop and prospectively evaluate a simpler new noninvasive method for determining aortic valve area. With this new method, aortic valve area is obtained by dividing the percent fractional anteroposterior shortening at the midventricular level by 4V2, where V is the peak instantaneous Doppler-derived flow velocity across the aortic valve. In the first part of the study, the fractional shortening-velocity ratio was used to examine a group of 25 patients evaluated retrospectively. There was a highly significant linear relation between the fractional shortening-velocity ratio (FSVR) and the aortic valve area (AVA) determined by the Gorlin formula at cardiac catheterization: FSVR = 1.1(AVA) - 0.1 (r = 0.88; significance of slope p less than 0.001). Furthermore, a fractional shortening-velocity ratio less than 1.1 reliably identified all patients with clinically significant aortic stenosis (aortic valve area less than 1 cm2), whereas a fractional shortening-velocity ratio less than 0.8 reliably identified all patients with critical aortic stenosis (aortic valve area less than 0.7 cm2). This new method was then validated by prospectively applying the fractional shortening-velocity ratio to a group of 44 patients from two separate institutions.(ABSTRACT TRUNCATED AT 250 WORDS)

Aortic Valve↗
PubMed1989

Left ventricular dysfunction in symptomatic mitral valve prolapse.

Idiopathic MVP is characterized by a late systolic click or murmur from myxomatous mitral valvular dysfunction. It may be complicated by atypical chest pain, ventricular arrhythmias, and ECG changes that can mimic the symptoms of coronary artery disease. We prospectively performed radionuclide cineangiograms before and after stress tests in MVP patients with chest pain compared with asymptomatic MVP patients and symptomatic normal control patients. In ten patients with MVP, chest pain, and normal coronary anatomy, the LVEF remained essentially unchanged (increase of -0.5 +/- 4 percent) after exercise. In ten patients with MVP and no chest pain and in nine with normal cardiovascular system and chest pain, the exercise LVEF increased by 11.5 +/- 2 percent (p less than 0.05) and 17.4 +/- 3 percent (p less than 0.005), respectively. The resting LVEF was significantly lower (p less than 0.02) in the symptomatic MVP patients (59 +/- 3 percent) than in the asymptomatic MVP (76 +/- 5 percent) or symptomatic normal patient control subjects (70 +/- 3 percent). Patients with MVP and chest pain had a lower resting LVEF and an abnormal left ventricular functional response to exercise compared with asymptomatic MVP patients or symptomatic normal subjects. Therefore, exercise radionuclide ventriculography may not adequately differentiate between chest pain due to MVP or coronary artery disease.

Cineangiography↗
PubMed1989

Intravenous streptokinase therapy for acute myocardial infarction in a community hospital: effect on ventricular function and mortality.

Streptokinase can dramatically impact upon management of myocardial infarctions in community hospitals. When given by experienced personnel during the first six hours after onset of symptoms, streptokinase is associated with a high patency rate, improved left ventricular function, and reduced mortality. Careful screening of patients results in a low complication rate with infrequent serious bleeding. Streptokinase should be utilized in those hospitals without cardiac catheterization facilities, but in light of the relatively high incidence of recurrent pain (15.8%), transfer of stable patients to a facility with a catheterization laboratory should be carried out within 24 to 72 hours. As approximately 60% of patients will require PTCA, CABG, or both, diagnostic cardiac catheterization should be considered in all patients unless there are other mitigating factors.

Acute Disease↗
PubMed1987

Incidence of acute myocardial infarction in patients with exercise-induced silent myocardial ischemia.

Fifty-five patients with angiographically proved coronary artery disease (CAD) underwent Bruce protocol exercise stress testing with thallium-201 imaging. Twenty-seven patients (group I) showed myocardial hypoperfusion without angina pectoris during stress, which normalized at rest, and 28 patients (group II) had a similar pattern of reversible myocardial hypoperfusion but also had angina during stress. Patients were followed for at least 30 months. Six patients in group I had an acute myocardial infarction (AMI), 3 of whom died, and only 1 patient in group II had an AMI (p = 0.05), and did not die. Silent myocardial ischemia uncovered during exercise stress thallium testing may predispose to subsequent AMI. The presence of silent myocardial ischemia identified in this manner is of prognostic value, independent of angiographic variables such as extent of CAD and left ventricular ejection fraction.

Angina Pectoris↗
PubMed1987

Predictors of outcome for aortic valve replacement in patients with aortic regurgitation and left ventricular dysfunction: a change in the measuring stick.

Although left ventricular function is generally regarded as a key determinant of prognosis in aortic regurgitation, predictors of outcome of aortic valve replacement based on this factor have recently been questioned. This study was performed to examine the role of indexes of left ventricular function in predicting the outcome of surgery in patients with aortic regurgitation and left ventricular dysfunction. Fourteen patients with aortic regurgitation with a preoperative ejection fraction of less than 0.55 (average 0.45 +/- 0.02) who underwent aortic valve replacement were studied. The patients had 82 (58%) of a possible 140 predictors of negative outcome preoperatively, but 12 of the 14 patients had a decrease in symptoms and an increase in ejection fraction into the normal range after operation (average postoperative ejection fraction 0.59 +/- 0.04). Although improvement occurred despite the presence of many negative predictors of outcome, there was a significant correlation between postoperative ejection fraction and eight of the tested preoperative predictors. Preoperative end-systolic dimension correlated best (r = -0.91) with postoperative ejection fraction. An end-systolic dimension of 60 mm correlated with a postoperative ejection fraction of 0.55. The results indicate that preoperative ventricular function is still an important determinant of outcome of aortic valve replacement for aortic regurgitation. However, current medical and surgical techniques permit a better prognosis in the presence of reduced ventricular function than was previously considered possible.

Aortic Valve Insufficiency↗
PubMed1985

Aortic valve endocarditis due to Salmonella enteritidis.

We have reported the fifth case of endocarditis due to Salmonella enteritidis and the first known survivor of native aortic valve endocarditis from this pathogen. Despite appropriate antibiotic therapy, aortic valve replacement was necessary because of heart failure and embolism. The patient also had concurrent viral hepatitis B infection.

Adult↗
PubMed1984

Congenital heart disease in adults.

From January 1972 to April 1982, 125 adults underwent operation for congenital heart disease at the Medical University of South Carolina. Age ranged from 18 to 73 years, with an average age of 31 years. A variety of defects were seen. Atrial septal defect (59 patients), ventricular septal defect (15 patients), patent ductus arteriosus (14 patients), tetralogy of Fallot (14 patients), and coarctation of the aorta (9 patients) were the most common. There were 48 men and 77 women in the study. Most patients presented with recent onset of dyspnea on exertion or at rest, but 16 patients were asymptomatic. Eight patients died after surgery for an overall operative mortality rate of 6 per cent. The most common postoperative complication was arrhythmia (13 patients, 10%). Despite recent advances in the diagnosis and treatment of congenital heart disease in infants, a significant number of patients apparently escape detection and first present with congenital heart disease as adults. Prompt diagnosis and surgical intervention will usually produce excellent results and relief of symptoms in these patients.

Adolescent↗
PubMed1981

Echocardiography in diagnosing and managing aortic valve endocarditis.

During a 36-month period, 14 patients were admitted with endocarditis of the native aortic valve. Echocardiography made a specific contribution to the diagnosis and/or therapeutic management in ten of the 14 (71%). Thirteen patients had aortic valve replacement because of congestive heart failure; only two were stable enough to complete antibiotic therapy prior to operation. There were 12 survivors, all of them alive and clinically improved at nine to 44 months (mean 27 months) of follow-up. There were no instances of recurrent endocarditis. The only medically treated patient died suddenly during the third week of antibiotic therapy. Ten of 14 patients were identified as having valvular vegetations by M-mode or two-dimensional sector echocardiography. Surgical or necropsy corroboration revealed 100% specificity (no false-positive results) and 71% sensitivity of this echocardiographic finding. Aortic valve endocarditis appears to be primarily a surgical disease in which echocardiography plays an important role.

Adolescent↗
PubMed1981

Supernumerary mitral valve producing subaortic stenosis.

A ten-year-old girl with severe subaortic stenosis was found to have relatively mature valvular endocardial cushion tissue (fibromyxomatous sheets with a chorda tendinea attached to a left ventricular papillary muscle) immediately beneath the aortic valve. This structure behaved like a valve mechanism, obstructing the left ventricular outflow tract during ventricular systole. This anomaly is an extreme on the spectrum of obstructive endocardial cushion malformations.

Aortic Stenosis, Subvalvular↗
PubMed1979

Development of aortic valvular vegetations during appropriate antibiotic therapy. Demonstration through serial echocardiograms.

The development of echocardiographically demonstrable vegetations on cardiac valves while the patient is receiving appropriate antibiotic therapy has not been previously reported. We report a case of alpha-hemolytic streptococcal endocarditis involving the aortic valve. Echocardiographically visualized vegetations were noted to occur on the 11th day of hospitalization. We discuss the role of serial echocardiograms in the management of patients with bacteremias and suspected endocarditis but absence of vegetations on the initial echocardiogram.

Aortic Valve↗