Physician perspectives on placebo ethics.

Clinical use of placebos is controversial among bioethicists. While placebos have been shown to provide benefit for patients with some conditions, offering placebos to patients without disclosing that they are placebos raises ethical concerns, including the concern that this lack of transparency about the nature of placebos amounts to deceiving patients. Some have proposed open-label placebos (OLPs) as an ethically preferable alternative: patients are offered placebos and told that the treatment being offered is a placebo. To contribute to the ongoing discussion about the ethics and feasibility of clinical use of placebos, we conducted focus groups to explore physician attitudes about clinical use of placebos, including non-disclosed and OLPs, and physician attitudes about the underlying ethical issues. We found that while the non-transparency and deceptiveness of offering non-disclosed placebos was a concern for some physicians, their primary focus when considering both non-disclosed and OLPs was identifying and weighing potential harms and benefits to patients. Some participants also felt further research and training in prescribing OLPs would be needed before they would be willing to use them in their practice.

Characterization of left ventricular cavity flow, wall stress and energy loss by color doppler vector flow mapping in children and adolescents with cardiomyopathy.

BACKGROUND: Vector flow mapping is an emerging echocardiographic method allowing for investigation of intracardiac blood flow mechanics, wall shear stress (WSS), and energy loss (EL). We hypothesized that alterations in EL and WSS will differ among subjects with hypertrophic (HCM), dilated (DCM) cardiomyopathy, and normal controls. METHODS: Echocardiograms were prospectively performed with the ProSound F75CV (Hitachi HealthCare., Tokyo, Japan) on all subjects. 2D color Doppler cine loop images were obtained from apical 5 and the apical long axis views and stored digitally. Measurements were averaged over three cardiac cycles using VFM software to derive flow patterns, WSS, and EL. Standard left ventricular (LV) systolic and diastolic functional parameters were also obtained. RESULTS: A total of 85 subjects, 22 with HCM (age 18 ± 9 yrs.), 18 DCM (age 18 ± 9 yrs.), and 45 age and gender matched controls were included in the study. Diastolic wall shear stress was found significantly different in HCM (0.004 ± 0.185 N/m2) compared with DCM (0.397 ± 0.301 N/m2, P < 0.001), and controls (0.175 ± 0.255 N/m2, P = 0.027). Furthermore, indexed systolic EL was found to be significantly elevated in HCM (13.91 ± 13.17 mW/m2/m3) compared with DCM (8.17 ± 9.77 mW/m2/m3, P < 0.001), but not controls (6.45 ± 7.47 mW/m2/m3). CONCLUSION: Differences in abnormal ventricular mechanics observed in HCM and DCM are reflected in both EL and WSS, and are suggestive that changes in energetic parameters may represent novel indices of ventricular dysfunction.

Progression of left ventricular diastolic function in the neonate and early childhood from transmitral color M-mode filling analysis.

BACKGROUND: We implemented sophisticated color M-mode analysis to assess age-dependent progression of left ventricular (LV) diastolic function. METHODS: Normal infants were prospectively enrolled for serial echocardiograms at 1 week, 1 month, 6 months, 1 year, and 2 years. From color M-mode scans, propagation velocity (VP), strength of filling (VS), and intraventricular pressure difference (IVPD) in 3 segments along apex-to-mitral valve scan line were measured. RESULTS: Age-wise comparisons of diastolic filling from 121 echocardiograms in 31 infants showed VP (cm/s), VS (cm2/s), and E-wave IVPD (mmHg) at 1 week to be 66.2 ± 11.9, 75.3 ± 19.9, and 1.5 ± 0.4, respectively, while VP, VS, and E-wave IVPD at 1 month were 80.3 ± 14.4, 101.2 ± 28.3, and 2.42 ± 1.1, respectively. There were significant differences in VP and segmental IVPD between first week and first month (p < 0.005) and IVPD between the age groups (p < 0.001). CONCLUSIONS: Comprehensive analysis of transmitral color M-mode data is feasible in infants, enabling calculation of pressure drop between the LV base and apex and strength of propagation from two distinct slopes. Profound changes very early followed by relatively constant filling mechanics in later infancy indicate significant LV maturation occurring during the first month of life. IMPACT: We implemented sophisticated analytic methods for color M-mode echocardiography in infants to assess age- and dimension-dependent changes in left ventricular diastolic function. Comprehensive characterization of transmitral color M-mode flow was feasible, enabling calculation of pressure drop between left ventricular base and apex and strength of propagation. Left ventricular diastolic filling function has predictable maturational progression, with significant differences in the intraventricular pressure between infants from birth to 2 years. This study forms the basis for future studies to examine alteration of early diastolic filling in congenital heart disease.