Biomedical subjects
Publications and source records attributed to Elyse Foster.
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Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
BACKGROUND: Population studies have identified the presence of bundle branch block (BBB) as a risk factor for increased mortality in patients with known cardiac disease. It is unknown how chronic ventricular dyssynchrony resulting solely from conduction delay affects ventricular function. METHODS AND RESULTS: Subjects were retrospectively identified from the University of California, San Francisco, electrocardiogram database with QRS prolongation. Subjects who had no evidence of heart disease and had baseline and serial studies evaluating ongoing risk of coronary artery disease status and left ventricular function were followed over time. Documentation of a minimum of 2 serial evaluations of cardiac status were present in a total of 51/176 (20%) subjects with isolated BBB who constitute the study population. After a mean follow-up of 52 +/- 45 months-adjusting for differences due to age, sex, the presence of hypertension, hyperlipidemia, and diabetes mellitus-left ventricular ejection fraction diminished by -7.3 +/- 12% per year in the isolated left BBB cohort versus -1.9 +/- 4% in isolated right BBB cohort and -1.1 +/- 3% reduction in the isolated nonspecific intraventricular conduction delay cohort (P =.019). CONCLUSIONS: Left bundle branch block itself may be a cause of ventricular dysfunction.
Catecholamines and alpha(1)-adrenergic receptors (alpha(1)-ARs) cause cardiac hypertrophy in cultured myocytes and transgenic mice, but heart size is normal in single KOs of the main alpha(1)-AR subtypes, alpha(1A/C) and alpha(1B). Here we tested whether alpha(1)-ARs are required for developmental cardiac hypertrophy by generating alpha(1A/C) and alpha(1B) double KO (ABKO) mice, which had no cardiac alpha(1)-AR binding. In male ABKO mice, heart growth after weaning was 40% less than in WT, and the smaller heart was due to smaller myocytes. Body and other organ weights were unchanged, indicating a specific effect on the heart. Blood pressure in ABKO mice was the same as in WT, showing that the smaller heart was not due to decreased load. Contractile function was normal by echocardiography in awake mice, but the smaller heart and a slower heart rate reduced cardiac output. alpha(1)-AR stimulation did not activate extracellular signal-regulated kinase (Erk) and downstream kinases in ABKO myocytes, and basal Erk activity was lower in the intact ABKO heart. In female ABKO mice, heart size was normal, even after ovariectomy. Male ABKO mice had reduced exercise capacity and increased mortality with pressure overload. Thus, alpha(1)-ARs in male mice are required for the physiological hypertrophy of normal postnatal cardiac development and for an adaptive response to cardiac stress.
The aim of this study is to prospectively validate a recently reported semiquantitative index of mitral regurgitation (MR) severity. MR is a common echocardiographic finding with no single reference standard to evaluate its severity. We recently developed and retrospectively tested a semiquantitative index of MR severity. The MR index is a composite of 6 echocardiographic variables: jet penetration, proximal isovelocity surface area, continuous-wave Doppler characteristics of the regurgitant jet, pulmonary artery pressure, pulmonary venous flow pattern, and left atrial size. Sixty-two consecutive patients with varying grades of MR were prospectively studied. Patients were divided into 3 groups for comparison: mild MR, moderate MR, and severe MR. Each patient was evaluated for the 6 variables, with each variable scored on a 4-point scale (0 to 3). The reference standards for MR severity were qualitative evaluation by an expert, measurement of the regurgitant fraction (RF), and the effective regurgitant orifice area. The MR index increased in proportion to MR severity with a significant difference among the 3 groups (F = 84; p <0.0001). The MR index also correlated with RF (r = 0.73; p <0.0001) and the effective regurgitant orifice area (r = 0.74; p = 0.0001). A MR index > or = 2.2 identified 13 of 16 patients with severe MR (sensitivity 82%, specificity 98%, positive predictive value 93%). No patient with severe MR had a score <2.0 and no patient with mild MR had a score >1.67. These results concurred with those obtained in a previously published retrospective study. Thus, the MR index is a simple, reproducible semiquantitative estimate of MR severity, that is widely applicable in routine clinical practice.
BACKGROUND: Long-term ventricular resynchronization therapy improves symptom status. Changes in left ventricular remodeling have not been adequately evaluated. METHODS AND RESULTS: Fifty-three patients with systolic heart failure and bundle-branch block underwent implantation of biventricular stimulation (BVS) devices as part of a randomized trial. Echocardiograms were acquired at randomization and at 6-week intervals until completion of 12 weeks of continuous BVS. There were no changes in heart rate or QRS duration after 12 weeks of BVS. Serum norepinephrine values did not change with BVS. After 12 weeks of BVS, left atrial volume decreased. Left ventricular end-systolic and end-diastolic dimensions and left ventricular end-systolic volume also decreased after 12 weeks of BVS. Sphericity index did not change. Measures of systolic function, including left ventricular outflow tract and aortic velocity time integral and myocardial performance index, improved. CONCLUSIONS: Long-term resynchronization therapy results in atrial and ventricular reverse remodeling and improved hemodynamics.
Anticoagulation of a pregnant woman is a complex issue for both the treating physician and the patient. In patients with mechanical prosthetic valves, long-term anticoagulation is mandatory to prevent thromboembolic complications; and in those with thrombophilic disorders and history of thromboembolism, anticoagulation is strongly indicated. With an increase in the number of patients with prosthetic heart valves, as well as the increase in maternal age, the issue of anticoagulation has become a very important one. Despite the widespread use of warfarin and unfractionated heparin during pregnancy, the optimal use of anticoagulants during pregnancy remains controversial because of a lack of appropriate prospective randomized clinical trials. In fact, even retrospective data on heparin provide miserably inadequate information for those making a decision on the correct dosing regimen. More recently, low molecular weight heparin has been proposed as a safer method of anticoagulation. This review summarizes current data and recommendations on anticoagulation during pregnancy.