ABSTRACT
Background: Coronavirus disease 2019 (Covid-19) has become a global pandemic. Covid-19 increases morbidity in patients with underlying cardiovascular disease. The six-minute walk test (6MWT) is a simple test for assessing cardiopulmonary fitness and has been applied to assess post-surgical recovery in cardiac populations. Decreased heart rate recovery (HRR) over 1 or 2 minutes after exercise shows autonomic dysfunction and is associated with an increased risk of mortality. We conducted a cross sectional study to determine if Covid-19 affects cardiac rehabilitation parameters, such as 6MWT distance, HRR-1, and HRR-2 among patients who have undergone cardiac surgery. Method(s): This analysis included 155 adults who had elective cardiac surgery at the National Heart Center Harapan Kita (NHCHK) from January to June 2022. Each participant performed a 6MWT and treadmill evaluation in phase II cardiac rehabilitation (CR) program. To analyze the association of 6mwt distances and heart rate recovery among patients with covid-19 and without covid-19 who had undergone elective cardiac surgery using Mann Whitney and Chi-Square tests. Result(s): Forty-Seven (30.3%) patients had a history of Covid-19. The mean 6MWT was 339.53 +/- 59.90 m in the pre-CR program, increased to 415.37 +/- 46.46 m in the post-CR program. The mean HRR1 was 15.16 +/- 9.44, and HRR2 was 56.59+/- 35.47. There were no differences in 6MWT distance, HRR1, and HRR2 among patients with a history of Covid-19 and without a history of Covid-19 (P= 0.48, p=0.56, p=0.12). Conclusion(s): The cardiac rehabilitation (CR) program improves the 6MWT distance. Covid-19 does not affect the ability of patients to do six-minute walk tests;neither HRR-1 nor HRR-2 among patients who have undergone cardiac surgery.
ABSTRACT
The crisis linked to the COVID-19 and the uncertainty it generates in the unprecedented health, societal, economic and financial fields have had a strong impact on the stock markets. Indeed, in such a climate of very high uncertainty, it is to be expected that the excessive stock market price movements will continue, with both declines and technical rebounds, and that the resulting volatility will remain particularly high. In order to cope with this crisis, investors and portfolio managers must mobilize all portfolio selection strategies. In particular, portfolio management and construction are based on the concepts of return and risk. This couple has been at the center of all the concerns of managers and investors in portfolio optimization issues since the introduction of the mean-variance model by Markowitz. However, many studies have proposed different measures of risk to overcome the drawbacks of variance. The objective of this paper is to present and compare the portfolio compositions and performance of four different portfolio optimization models using different risk measures, including variance, Mean Absolute Deviation, Gini coefficient and Lower Partial Moments (LPM). The results of this study show that the Mean-Lower Partial Moments (MLPM) model outperforms other models. The Mean-Lower Partial Moments (MLPM) model is suitable for investors during the crisis period (COVID-19) in the Moroccan financial market. © 2020 ASTES Publishers. All rights reserved.