Biomedical subjects

R Wikh

Publications and source records attributed to R Wikh.

3 recordsLinked to original sources

PubMed2000

Early changes in longitudinal performance predict future improvement in global left ventricular function during long term beta adrenergic blockade.

OBJECTIVE: Contraction of longitudinal and subendocardial myocardial muscle fibres is reflected in descent of the atrioventricular (AV) plane. The aim was therefore to determine whether beta blocker treatment with prolongation of diastole might result in improved function as reflected by AV plane movements in patients with chronic heart failure. DESIGN: Double blind, randomised, placebo controlled and open intervention study. SETTING: University hospital. PATIENTS: Patients with congestive heart failure: placebo controlled (n = 26) and an open protocol (n = 15). INTERVENTIONS: 12 months of metoprolol treatment. MAIN OUTCOME MEASURES: Short axis and long axis echocardiography, invasive haemodynamics, radionuclide angiography. RESULTS: Recovery of systolic and diastolic function during metoprolol treatment was reflected by early changes in mean (SD) AV plane amplitude, from 5.3 (2.0)% to 7.1 (3.2)% and 7.8 (3. 1)% (at 3 and 12 months, respectively; p < 0.05). In a multivariate analysis, only the change in AV plane amplitude by three months was independently associated with improvement in pulmonary capillary wedge pressure by six months (r = 0.80, p = 0.017). Change in AV plane amplitude by three months was also a better predictor of improvement in ejection fraction by 12 months (r = 0.78, p < 0.001) than changes in radionuclide ejection fraction by three months (r = 0.34, p = 0.049). CONCLUSIONS: Improvement in longitudinal contraction was closely associated with a decrease in left ventricular filling pressure during metoprolol treatment. This association was stronger than changes in short axis performance or radionuclide ejection fraction, emphasising the importance of AV plane motion for left ventricular filling and systolic performance in patients with heart failure.

Adrenergic beta-Antagonists↗

PubMed1998

New concept in echocardiography: harmonic imaging of tissue without use of contrast agent.

BACKGROUND: Endocardial border detection is important for echocardiographic assessment of left-ventricular function. Second harmonic imaging of contrast agents enhances this border detection. We discovered that harmonic imaging improves tissue visualisation even before contrast injection. We therefore sought objectively to demonstrate the degree of enhancement of endocardial and myocardial visualisation. METHODS: An ATL HDI-3000 scanner with software for contrast harmonic imaging was used to record short-axis images of the left ventricle in 27 patients with possible myocardial disease and 22 controls, in the fundamental mode and with harmonic imaging. A computer program measured the relative grey-scale values within six segments of the endocardium and myocardium. An Acuson Sequoia scanner equipped with software for tissue harmonic imaging was used to investigate the reproducibility of ejection-fraction calculations in 22 patients with ischaemic heart disease. FINDINGS: Harmonic imaging produced brighter endocardium within each segment. Relative to the mean grey value of the total imaging sector, the values for harmonic and fundamental imaging were 171.5 vs 85.6% (p<0.0001) in end diastole and 194.1 vs 106.7% (p<0.0001) in end systole. Results for the myocardial segments were also significantly better for harmonic imaging. Structure enhancement of similar magnitude was seen among patients and healthy controls. Use of harmonic imaging reduced the proportion of unacceptable images by 14-46% in different views and improved the reproducibility of biplane ejection-fraction measurements. INTERPRETATION: In comparison with fundamental imaging, the relative endocardial and myocardial brightness is enhanced by harmonic imaging.

Aged↗

PubMed1996

Early effects of coronary artery bypass surgery and cold cardioplegic ischemia on left ventricular diastolic function: evaluation by computer-assisted transesophageal echocardiography.

OBJECTIVE: Although left ventricular (LV) systolic function undergoes a temporary decrease after cardiopulmonary bypass (CPB) in patients undergoing coronary artery bypass grafting (CABG), data on the effects of CABG and cardioplegic arrest on LV diastolic function are contradictory. The objective of the present study was to further evaluate the effects of CABG and CPB on LV diastolic function. DESIGN: A prospective study. SETTING: A multi-institutional investigation at a university hospital. PARTICIPANTS: 20 patients on beta-receptor antagonists, scheduled for CABG and with a preoperative ejection fraction over 0.5. INTERVENTIONS: Central hemodynamic measurements, transesophageal LV short-axis images, and mitral Doppler flow profiles were obtained before and after volume loading that in turn was performed both before surgical incision and after weaning from CPB. MEASUREMENTS AND MAIN RESULTS: Heart rate, cardiac output, and peak atrial filling velocity increased; systemic vascular resistance decreased; whereas stroke volume, LV area ejection fraction, deceleration rate and slope of early diastolic filling, time-velocity integral of early diastolic filling, and the ratio between early and atrial peak filling velocity were unchanged post-CPB compared with pre-CPB. LV end-diastolic stiffness that was calculated for each patient pre-CPB and post-CPB using the formula: P = B*eS*A), where P is the LV filling pressure and A is the end-diastolic short-axis area, was unchanged post-CPB compared with pre-CPB. CONCLUSIONS: Both the active and passive components of LV diastolic function are well maintained shortly after CABG and cardioplegic arrest in patients with a good preoperative systolic LV function.

Coronary Artery Bypass↗