Updated pathophysiological overview of functional MR (ventricular and atrial).

Basic mechanism of ventricular functional mitral regurgitation (FMR) is subvalvular tethering. Left ventricular (LV) dilatation, in association with mitral valve (MV) annular dilatation, causes outward displacement of papillary muscles (PMs), which abnormally pulls or tethers MV leaflets, resulting in MV tenting, reduction in leaflets coaptation and MR. Because surgical annuloplasty does shorten distance between anterior and posterior MV annuli to improve coaptation but does not address this subvalvular tethering, ventricular FMR frequently persists or recurs in the chronic stage after surgical annuloplasty. This high incidence of persistent/recurrent MR requires additional procedures to reduce subvalvular tethering. Although patients occasionally show marked improvements after annuloplasty with surgical tethering reduction procedures such as PM approximation, evidence to support benefits of such surgery is limited, requiring further trials. Recently, MV adaptation or MV leaflets tissue growth associated with LV dilatation attracts attention. Patients with larger MV leaflets with significant LV dilatation/dysfunction show less MV tethering and MR compared to those with smaller MV leaflets but with similar LV remodeling, suggesting the protective or beneficial role of MV leaflets tissue growth against LV remodeling. The MV leaflets tissue growth has the potential to lead to novel strategies of treatment for ventricular FMR. It is well known that atrial FMR is frequent in patients with left atrial dilatation, typically in those with isolated atrial fibrillation. The degree of atrial FMR is usually mild, even when it is present, and occasionally moderate, and severe atrial FMR is really rare. It is known that only severe regurgitation causes heart failure in primary MR, resulting in description on indications of surgery or intervention for only severe MR in current guidelines. Therefore, this atrial FMR up to moderate degree did not attract attention for a long time. However, recent studies have shown that patients with only moderate atrial FMR develop severe heart failure, suggesting more aggressive indication of MV surgery or intervention for "moderate" regurgitation in patients with atrial FMR. Therefore, atrial FMR is now recognized highly important. The unveiled malignant nature of atrial FMR arises many questions, including (1) why patients with only moderate atrial FMR develop heart failure? (2) do patients with mild atrial FMR develop heart failure or not?, and many others. Atrial FMR seems even more mysterious after the unveiling of its significance.

Potential Effects of Mild Atrial Secondary Mitral Regurgitation in Patients With Isolated Atrial Fibrillation.

BACKGROUND: Patients with only moderate atrial secondary mitral regurgitation (asMR) frequently develop heart failure (HF). Mechanisms of HF with moderate asMR and the impact of mild asMR remain unclarified. Although mild/moderate primary mitral regurgitation is compensated by left ventricular (LV) dilatation, the LV is not dilated in asMR. We hypothesized that patients with mild asMR without LV dilatation may have impaired hemodynamics and higher risks of subsequent symptomatic HF deterioration. METHODS: Stroke volume, cardiac output, and systolic pulmonary artery pressure were measured by echocardiography in 142 patients with isolated atrial fibrillation and 30 healthy controls. The prognosis of patients with isolated atrial fibrillation was followed up. RESULTS: In the 142 patients with isolated atrial fibrillation, asMR was no/trivial in 55, mild in 83, moderate in 4, while none had severe asMR. Compared with controls and patients with no/trivial asMR, LV end-diastolic volume index was not increased and hemodynamic parameters were abnormal in patients with mild asMR (LV end-diastolic volume index, 65±6 versus 58±8 versus 60±8 mL/m²; stroke volume index, 42±4 versus 35±4 versus 29±6 mL/m²; P<0.001 versus other 2 groups; cardiac output index, 2.8±0.4 versus 2.8±0.5 versus 2.3±0.6 L/min per m²; P<0.001; systolic pulmonary artery pressure, 21±3 versus 26±5 versus 37±9 mm Hg; P<0.001). Although the event-free rate of HF symptomatic deterioration or hospitalization in patients with no/trivial asMR during a median 13.9 months follow-up was 86.9% and 100%, the rate in mild asMR was 59.4% and 85.0% (P<0.001 or P=0.032), respectively. CONCLUSIONS: In the presence of isolated AF and no compensatory LV dilatation, impaired hemodynamics and higher risks of symptomatic HF deterioration were associated with mild asMR, requiring further studies of causalities.

Spread of infection and treatment interruption among Japanese workers during the COVID-19 pandemic: A cross-sectional study.

Background: The COVID-19 pandemic has resulted in treatment interruption for chronic diseases. The scale of COVID-19 in Japan has varied greatly in terms of the scale of infection and the speed of spread depending on the region. This study aimed to examine the relationship between local infection level and treatment interruption among Japanese workers. Methods: Cross-sectional internet survey was conducted from December 22 to 26, 2020. Of 33,302 participants, 9,510 (5,392 males and 4,118 females) who responded that they required regular treatment were included in the analysis. The infection level in each participant's prefecture of residence was assessed based on the incidence rate (per 1,000 population) and the number of people infected. Age-sex and multivariate adjusted odds ratios (ORs) of regional infection levels associated with treatment interruption were estimated by multilevel logistic models, nested by prefecture of residence. The multivariate model was adjusted for sex, age, marital status, equivalent household income, educational level, occupation, self-rated health status and anxiety. Results: The ORs of treatment interruption for the lowest and highest levels of infection in the region were 1.32 [95 % confidence interval (CI) were 1.09-1.59] for the overall morbidity rate (per 1,000) and 1.34 (95 % CI 1.10-1.63) for the overall number of people infected. Higher local infection levels were linked to a greater number of workers experiencing treatment interruption. Conclusions: Higher local infection levels were linked to more workers experiencing treatment interruption. Our results suggest that apart from individual characteristics such as socioeconomic and health status, treatment interruption during the pandemic is also subject to contextual effects related to regional infection levels. Preventing community spread of COVID-19 may thus protect individuals from indirect effects of the pandemic, such as treatment interruption.

Novel noninvasive estimation of mixed venous oxygen saturation by echocardiography and expired gas analysis.

Mixed venous oxygen (O2) saturation ([Formula: see text]) is an important measure for evaluating the sufficiency of cardiac output (CO) relative to whole body O2 consumption (V̇o2), while clinical use is limited to the required invasive catheterization. According to Fick's equation, V̇o2 (mL/min) = CO (L/min) × Hb (g/dL) × 1.36 (mL/g) × ([Formula: see text] - [Formula: see text])/10 (Hb = hemoglobin concentration, [Formula: see text] = arterial blood O2 saturation). Because V̇o2, CO, Hb, and [Formula: see text] can be measured noninvasively with expired gas analysis, echocardiography, a simple blood test, and percutaneous O2 saturation, respectively, [Formula: see text] can be calculated noninvasively. We hypothesized that noninvasively calculated [Formula: see text] shows a significant correlation and agrees well with invasively measured [Formula: see text]. In 47 patients (29 men; mean age, 70 ± 12 yr) who underwent right heart catheterization, [Formula: see text] was directly measured by sampling pulmonary artery blood. Noninvasively calculated [Formula: see text] was also obtained by the method described above. The calculated [Formula: see text] was significantly correlated with the measured [Formula: see text] (r = 0.79, P < 0.001) and was significantly smaller than the measured [Formula: see text] (70 ± 5.1 vs. 72.1 ± 4.9%, P < 0.001). Bias at [Formula: see text] was -2.2% (95% confidence interval, -3.2 to -1.1%) with limits of agreement from -9.5 to 5.2%, demonstrating acceptable agreement. The optimal cutoff value of calculated [Formula: see text] was 69% for reduced measured [Formula: see text] < 70% with an area under the curve of 0.94. Reduced calculated [Formula: see text] < 69% indicated a sensitivity of 92.9% and a specificity of 90.9% for reduced measured [Formula: see text] < 70%. Noninvasive [Formula: see text] calculated from echocardiography, expired gas analysis, percutaneous arterial blood O2 saturation, and hemoglobin level significantly correlated and agreed well with direct [Formula: see text] measured by catheterization. This novel method allows for practical evaluation of [Formula: see text] to assess the sufficiency of CO according to whole body metabolism.NEW & NOTEWORTHY Clinical use of mixed venous oxygen saturation ([Formula: see text]) is limited to the required invasive procedure. With Fick's equation, expired gas analysis, echocardiography, simple blood tests, and percutaneous oxygen saturation, [Formula: see text] can be calculated noninvasively. We hypothesized that noninvasively calculated [Formula: see text] shows a significant correlation and agrees well with invasively measured [Formula: see text]. The present study examined the relationship between measured [Formula: see text] and calculated [Formula: see text] in patients who underwent right heart catheterization and demonstrated acceptable agreement. This novel method can expand the indication of evaluating [Formula: see text].

Young adult preferences for physician decision-making style in Japan and the United States.

Studies in Japan and the United States investigate preferences for patient-physician decision-making style among young adults in the context of a primary care clinic visit for an upper respiratory infection. A treatment scenario described 1 of 3 decision-making styles: a young adult and doctor using a passive (physician decides), shared (patient and physician decide together), or autonomous (patient decides from a set of medically appropriate alternatives) decision-making style. Unexpectedly, Japanese respondents evaluated the autonomous interaction most positively. US respondents evaluated the shared decision-making scenario most positively. Overall, despite large cultural differences, both country samples favored higher participation in decision making. These results suggest that passive patient approaches are falling out of favor as patient-centered care expectations diffuse globally, even in traditionally hierarchic societies with high levels of respect for authority. The implications of these findings along with managerial implications and suggestions for future research are presented.