جستجوی مقالات مرتبط با کلیدواژه "بیماری های قلبی عروقی" در نشریات گروه "پزشکی"

This article is an update on our previous review of clinical studies on the role of polypills in the secondary prevention of cardiovascular diseases (CVD). We also present the preliminary results of the Persian Polypill study.

Persian Polypill is a randomized clinical trial with two parallel arms on hospitalized patients due to acute myocardial infarction (AMI). It is planned that 1100 patients will be randomly assigned to one of the two arms of Polypill or usual care and will be followed up for 34 months. The primary outcome will be a composite clinical outcome of major adverse cardiovascular events (MACE), and the secondary outcome will be the cost-effectiveness of polypill treatment.

We identified ten completed studies and two ongoing trials in which at least 10% of participants had CVD. The evaluation of these studies showed the lack of research in low- and middle-income countries about the role of polypill in secondary prevention of CVD and limited information about cost-effectiveness resulting from clinical trials. In Persian Polypill, so far, 624 patients admitted to three hospitals due to AMI have been included in the study. The average age of patients is 60.9 ± 8.7 and 506 are male (81.1%). Overall, 94.4% of the patients underwent percutaneous coronary intervention in the hospital, and 26.3% had hospital complications.

The final results of this study can compensate for the gap in the past studies. They may confirm the role of polypill in the initial management of AMI and long-term secondary prevention in these patients.

In recent years, the field of biology has witnessed the discovery of new molecules with remarkable functions. One of these molecules is circular RNAs (CircRNAs), which are part of the large family of noncoding RNAs. These RNAs are abundantly present in body tissues and are located either in the cytoplasm or stored in exosomes, where they are not affected by cellular RNA exonucleases. Unlike other linear RNAs, circular RNAs lack free ends and therefore possess a more stable structure compared to linear transcripts. These unique characteristics make them ideal candidates for use as biomarkers. It is well established that these special RNAs play an important role in regulating gene expression. Furthermore, studies have demonstrated that circular RNAs play a crucial role in a wide range of biological processes, including cell proliferation, apoptosis, and aging. Importantly, circular RNAs are described as microRNA sponges. This mechanism, which has been extensively studied in cancers, holds promise as a biomarker in other diseases, particularly cardiovascular diseases. This study aims to evaluate the role of circular RNAs as biomarkers in the prognosis of cardiovascular diseases.

 To overcome the limitations of the definition of metabolic syndrome (MetS) in clinical use, a health index named quantitative Metabolic Syndrome Severity Score (cMetS-S), has been recently introduced and validated in the Tehran Lipid and Glucose Study. This study investigated the association between the severity of MetS based on age and gender (cMetS- score), and cardiovascular diseases (CVD) beyond the components of MetS.

 At the beginning of the study, participants aged 20-60 years were enrolled. Those with cardiovascular disease, cancer, use of corticosteroid, estimated glomerular filtration rate <30 ml/min/1.73m², or pregnancy were excluded. The association between cMetS-S and cardiovascular diseases was evaluated continuously for 18 years follow-up among 8,500 participants using Cox proportional hazards regression models and its performance in predicting cardiovascular disease events was compared with the MetS criteria.

 Participants with higher cMetS-S showed a significant increase in the risk of cardiovascular disease (CVD), coronary heart disease (CHD), and non-coronary heart disease (non-CHD). Independent of the confounding factors of metabolic syndrome components, each 1-SD unit increase in cMetS-S was associated with risk ratios of 1.67, 1.60 and 1.88 for cardiovascular diseases, coronary and non-coronary cardiac events, respectively. Model fit analysis showed better CVD prediction value for cMetS-S independent of (MetS) components, compared with metabolic syndrome (p<0.0001).

 The cMetS-S predicts cardiovascular diseases more accurately than the MetS and its components. The standardized cMetS-S, which considers the weighted contribution of MetS components and their variations by age and gender, may serve as a health metric for determining the severity of metabolic syndrome.

The association between the consumption of dairy products and the risk of cardiovascular disease (CVD) is not well-known yet. Here, we aimed to determine the potential effects of total intake and subtypes of dairy products on the development of CVD in an Iranian adult population.

Among adult participants of the third phase of the Tehran Lipid and Glucose Study (TLGS), after excluding those with incomplete dietary, biochemical and anthropometric data, and those who had CVD events at baseline, 2635 adults were selected and followed up till the sixth phase of the TLGS. Baseline dietary intakes were evaluated using a validated food frequency questionnaire with 168 items. There was no significant difference between the baseline characteristics of participants who did not complete the FFQ and those of the total population in the third phase of the TLGS. Finally, the risk of CVD events after adjusting for potential confounding variables was evaluated across the tertile categories of dairy products using the Cox proportional hazard regression models.

During a 10.6-year follow-up, the incidence rate of CVD was 6.5%. After adjusting for confounding factors, there was no significant association between CVD risk and total dairy, low-fat and high-fat dairy, fermented and non-fermented dairy products, high- and low-fat milk, high- and low-fat yogurt, cheese, and cream cheese, as well as ice cream.

According to numerous evidence in previous studies that revealed there is no association between the consumption of dairy products, and CVD risk, independent of high-fat or low-fat dairy products. Hence, it is vital to reconsider dietary recommendations on lowering the intake of high-fat dairy products for the prevention of CVD.

Knowledge, positive attitude, and proper practice are the most important factors in controlling cardiovascular complications in chronic diseases such as diabetes. So, this study investigated the knowledge, attitude, and practice of cardiovascular disease prevention in patients with type 2 diabetes.

In this descriptive-cross-sectional study, 385 patients with type 2 diabetes who visited the Diabetes Clinic of Ganjavian Dezful Hospital from January 2023 to April 2024 were selected by convenience sampling method. To collect data, the demographic information questionnaire and the questionnaire by Koohi et al. (2021) related to the knowledge, attitude and practice of prevention of cardiovascular diseases were used. The Cronbach's alpha of the questionnaire was >0/6 for all dimensions of the questionnaire, and its CVR and CVI in this study were 0/90 and 0/85. Data were analyzed using SPSS version 16 software and p-value of less than 0.05. Descriptive statistics including frequency, mean, and standard deviation as well as inferential statistics such as Pearson correlation, independent t test, and ANOVA were used to analyze the data.

This study showed that 57.1 percent of the participants were in the age range of 40 to 60 67/5 percent of whom were women. Patients had a high level of knowledge and attitude toward preventing cardiovascular disease (20/06 ± 5/42) and (46/80 ± 4/99), respectively); however, their performance level was not high (8.65 ± 5.03). A significant positive relationship was also observed between knowledge and attitude (r = 0/6, P= 0/001).

Despite patients’ high level knowledge and attitude toward the prevention of cardiovascular diseases, their performance in this field is not appropriate, and this issue requires planning by hospital managers

Cardiovascular diseases are among the most lethal physical diseases of the 21st century, posing a greater threat to human life than any other disease and problem. This research compared the effectiveness of mindfulness-based stress reduction and emotion-focused therapy on the cognitive flexibility of cardiovascular patients in Isfahan City. The research was conducted using a quasi-experimental design with a pre-test-post-test and a three-month follow-up with a control group. The statistical population included 380 male cardiovascular patients admitted to Shahid Chamran Cardiovascular Hospital in Isfahan in the winter of 2023. Forty-five patients were selected by purposive sampling and randomly assigned to two experimental groups and one control group. Patients in the first experimental group received eight 90-minute sessions of mindfulness-based stress reduction, while those in the second experimental group received eight 90-minute sessions of emotion-focused therapy. The measurement tools were the Cognitive Flexibility Questionnaire (Dennis & Vanderwaal, 2010) and a short clinical interview. Research data were analyzed through mixed variance analysis using SPSS version 24 software. The results showed that both intervention methods increased the average cognitive flexibility and its components, including alternatives, control, and alternatives for human behaviors of patients (P≥0.01). No significant difference was observed between the effectiveness of the two methods (P≤0.01). According to the research results, it is possible to use the intervention method of mindfulness-based stress reduction program and emotion-focused therapy to improve the cognitive flexibility of cardiovascular patients.

Today, cardiovascular diseases are one of the main causes of death. This study was conducted to compare the effect of resistance and endurance training on predictors of cardiovascular diseases and arteriosclerosis in aged male rats.

The present study is an experimental and fundamental research with a control group conducted in 2021 in the basic science laboratory of Shahrekord University in Iran. Fifty elderly male Wistar rats with an average weight of 432.7±4.4 grams and an age of 23±2 months were randomly divided into five groups. The control group was divided into two resistance training groups (climbing a special ladder) and two continuous training groups (running on a treadmill), and they did the training protocols for eight weeks and five sessions every week. Data analysis was performed using a one-way analysis of variance and Bonferroni post hoc test with SPSS 22 software at p≤0.05 level.

The results of the present study showed that the level of HDL increased significantly in all four training groups compared to the control group (p≤0.05). LDL level and LDL/HDL ratio decreased significantly in all four training groups compared to the control group (p≤0.05). The level of TC decreased significantly only in the high-intensity resistance training group (p≤0.05). Even though both training methods led to changes in the levels of TG, VLDL, ApoA1, ApoB, and ApoB/ ApoA1 ratio, these changes were not statistically significant (p>0.05). The difference between the two training methods was insignificant (p>0.05).

Both training methods caused positive changes in HDL, LDL factors, and LDL/ HDL ratio. Performing both training methods is recommended for older adults and people at risk, especially the military, although endurance training has more effect and fewer risks.

Food insecurity and poor quality of diet are among risk factors of cardiovascular diseases (CVD). The main objective of this study was to assess the association of food insecurity with atherogenic glucose and lipid profile in women.

In this cross-sectional study, 630 women between 18 and 50 years of age were selected by cluster sampling and interviewed face-to-face. To assess the household’s food security status, we used a household food insecurity access scale (HFIAS) questionnaire, which its validity and reliability had been determined in the Iranian population. The serum levels of glucose (FBS), triglyceride (TG), total cholesterol (TC), low-density lipoprotein (LDL), and high-density lipoprotein (HDL) were measured and LDL/HDL, TC/HDL, and TG/HDL ratios were calculated.

The mean serum concentrations of TG and TG/HDL ratio were significantly higher in the women suffering from moderate and severe food insecurity compared to those in the food-secure women (p=0.002). Compared with the food secure group, women with moderate and severe food security were more likely to develop hypertriglyceridemia (adjusted OR, 1.63; p=0.018) and a high TG/HDL ratio (adjusted OR, 1.52; p=0.030). However, food security status showed no significant associations with the probability of having the impaired fasting glucose, hypercholesterolemia, high LDL, low HDL, and abnormal ratios of LDL/HDL and TC/HDL.

Food insecurity may be associated with increased risk of hypertriglyceridemia and high TG/HDL in women.

Psychological factors might play a role in the onset and exacerbation of cardiovascular disease. This study aimed to determine the relationship between Alexithymia and Emotional Maturity with the mediation of Attachment Styles among cardiovascular patients in Zanjan, Iran. The present study has a descriptive-correlational design. The statistical population of this study encompassed a range of 670 patients with cardiovascular diseases who were referred to the Cardiology Clinic of Ayatollah Mousavi Hospital in Zanjan from March and August 2019. The sample size was estimated to be 244 people using Cochran formula. Data collection tools included Hazen and Shaver’s standard adult attachment style questionnaire, Toronto’s ataxia, and Singh and Bhargava questionnaires. The Pearson correlation coefficient and multiple regression analyses were done using SPSS 24 software. There was a positive correlation between alexithymia with emotional instability (r=0.14, P<0.01), personality decay (r=0.36, P<0.01), and emotional maturity (r=0.38, P<0.01). The results of multiple regression analysis showed that emotional instability (P=0.009), personality decay (P=0.016), and emotional immaturity (P=0.009) significantly predicted secure style. Additionally, difficulty in describing emotions significantly predicted avoidant style (P=0.034). Emotional maturity (P=0.006) and difficulty recognizing emotions (P=0.009) also significantly predicted ambivalent style. Personality traits and emotional alexithymia can be used as indicators for predicting attachment styles and social behaviors, and specifically, lack of emotional stability, personality disintegration, and emotional alexithymia can predict secure and ambivalent styles to some extent. Also, difficulty in describing emotions and emotional immaturity have the ability to predict the avoidant style. These results can help to better understand individual behaviors and design solutions to improve behavior.

The changes in the causes of death in South Khorasan province, Iran, during 2002-2022 were examined in the present research. According to the data available in the “Mortality Data Registery” during these 20 years, cardiovascular diseases (CVD) was the most common cause of death, and its rate has increased from 20% in 2002 to about 37.8% in 2022. Even during the COVID pandemic, CVD was the first cause of death in the province. In 2022, the most common causes of death were CVD (37.8%), respiratory diseases (15.2%), cancers (14%), and accidents (9.2%). One of the most effective factors in preventing CVD is paying attention to"Life’s essential 8 Cardiovascular Health", i.e., having normal blood glucose, blood pressure, serum lipids, body mass index, sufficient physical activity, healthy diet, sufficient night sleep, and being a non-smoker. In addition to individuals’ attention to these factors, it is necessary for healthcare system decision-makers to have systematic and continuous planning to enhance people's awareness and attitude regarding these eight factors.

In Iran, half of all deaths and 79% of deaths from non-communicable diseases are attributed to cardiovascular diseases. On the other hand, more than 76% of the total burden of diseases and the first cause of catastrophic health expenses in Iran are related to these diseases. This study was conducted with the aim of determining the status and trend of providing cardiovascular disease risk assessment services by gender, in order to carry out the necessary interventions in the comprehensive health service centers of Ardabil province, Iran.

The present descriptive study was conducted in Ardabil University of Medical Sciences. It used the data available in the registration system of the Health Network. The research population consisted of all men and women aged between 40 and 80 who visited the comprehensive health service centers to perform risk assessment of cardiovascular strokes in the province from 2018 to the end of 2022. The data were entered into Excel software. FORCAST function was used to predict the future through a linear regression analysis. To compare the final results, which is actually a reduction in mortality due to cardiovascular diseases, the difference test of two mortality rates due to cardiovascular diseases was used in 2018 and march 2023.

The results showed a relatively high prevalence of some risk factors for cardiovascular diseases including history of hypertension, diabetes, abdominal obesity, suspected diabetes, lipid disorder, body mass index of 30 and above in women. Also, the results of the study showed that 38.3% of men and 61.72% of women were at the risk level of 10-20%, 34.8% of men and 65.2% of women were at the risk level of 20-30%, and 28.9% of men and 71.1% of women were at the risk level above 30%.

Women were more at risk of cardiovascular diseases and complications than men. Knowing the common risk factors in the region helps to focus interventions on effective prevention and treatment measures and to adopt evidence-informed policies in order to reduce these risk factors.

Fetuin-A, as a hepatokine, plays an important role in the regulation of whole-body metabolism, which is increased with chronic diseases. Therefore, the aim of this meta-analysis is to investigate the effect of exercise training on Fetuin-A levels in individuals with metabolic and kidney diseases.

A systematic search was conducted in PubMed, Web of Science, and Google Scholar databases until November 2022 using the keywords "exercise training" and "Fetuin-A". To determine the effect size, standardized mean difference (SMD) and 95% confidence interval were calculated using CMA2 software. Heterogeneity was evaluated using the I2 test, and publication bias was evaluated by visual interpretation of the funnel plot and Egger's test. The quality of the included studies was evaluated using the PEDRO checklist.

A total of 16 studies including 21 trials arms and 554 subjects with type 2 diabetes, obesity and kidney disease were included in the meta-analysis. Exercise training resulted in a significant decrease in Fetuin-A levels [-0.93 (CI: -1.35 to -0.51) P= 0.001]. There was a high heterogeneity (I2= 89.24, P= 0.001) and also a significant publication bias (P= 0.001). The results of subgroup analysis based on the type of exercise training showed that aerobic training resulted in a significant decrease in Fetuin-A (P= 0.001) while the reduction of this marker with combined training was not significant (P= 0.33).

Exercise training, especially aerobic training, results in a decrease in Fetuin-A levels in metabolic patients, which may be contributed to the beneficial effects of exercise.

Cardiovascular disease is the most common cause of death. Improving the quality of the diet, such as increasing the consumption of whole grains, vegetables, and fruits, has a beneficial effect on cardiovascular complications. The Qur'an is a heavenly book in which there are 11 words about fruits and their derivatives, which indicates the value of fruits from the Quran's point of view. In general, the holy book of Qur'an has highlighted 5 fruits including olives, figs, dates, pomegranates and grapes and has repeated them in various verses.

In this review study, noble verses of Qur'an, books on interpretation of Quran and reliable scientific databases such as Web of Science, PubMed, Scopus, IranMedex, Magiran, SID and Google Scholar were reviewed from 2000 to 2021. Related articles were reviewed using the keywords of Quran, olives, grapes, dates, figs, pomegranates, and cardiovascular disease.

The results suggest that the fruits mentioned in the Qur'an such as olives, figs, dates, grapes, and pomegranates, play a major role in human nutrition and health due to their strong antioxidant effects, which reduce oxidative stress, and substances such as carotenoids, anthocyanins, and phenolics. The results of the studies have shown the anti-inflammatory and antioxidant role of these fruits. It has been proven that these fruits have a high potential to prevent cardiovascular diseases, reduce the complications of cardiovascular diseases and improve the health of these patients.

The results of the studies have suggested that consumption of the fruits mentioned in the Qur'an reduces the risk of cardiovascular events, causes recovery in cardiovascular patients and reduces mortality due to cardiovascular diseases.

Cardiovascular diseases, including ischemic heart disease (IHD), are one of the main cause of mortality and morbidity worldwide and are currently one of the top ten causes of death. Ischemic heart disease is a type of heart disease that is caused by narrowing of arteries feeding the heart itself. The present study aimed to use data mining algorithms in screening and early prediction of IHD according to the patient's characteristics and risk factors.

In this research, data of the first phase of Yazd Health Study (YaHS), focusing on 21 characteristics of 10,000 participants aged 20-70 years such as age, type of chest pain, blood sugar level, body mass index, employment status, etc. which have been collected since 2013 were analyzed.

Data analysis was conducted using Random Forest and Naive Bayes algorithms which showed 74.51% accuracy in predicting IHD.

The study findings revealed that via applying Random Forest and Naive Bayes algorithms, ischemic heart disease can be predicted with high accuracy. Moreover, early screening and timely treatment in the early stages of disease may reduce mortality and morbidity.

Breast cancer is one of the most common cancers and the fifth leading cause of cancer deaths in Iran. The present study aimed to investigate the absorbed dose received by the heart and its relationship with cardiac complications in radiotherapy of patients with left breast cancer using a three-dimensional conformal radiotherapy technique.

A total of 181 women with left breast cancer who received radiotherapy after surgery were included in the study. Dosimetric parameters were obtained using dose-volume histograms for the heart, whole lung, left lung, and clinical target volume. Electrocardiography tests were performed for all patients before and one year after the radiotherapy.

The mean doses of heart, left lung, whole lung, and clinical target volume were 6.3±3.1, 13.3±4.5, 6.9±3.7, and 47.3±6.4 Gray (Gy), respectively. A significant reduction in T-wave amplitude was observed in 57% of patients three months after radiotherapy. T-wave amplitude decreased from 3.03±0.92 mm to 1.56±0.83 mm. The reduction in the T-wave amplitude displayed a significant relationship with the mean dose of the heart (β = 2.653; P= 0.019).

In women with left-sided breast cancer, cardiac complications are frequent, for which electrocardiographic tests can be used for cardiac evaluation after radiotherapy. Based on the obtained results, the most frequent side effect caused by radiotherapy in these patients was an abnormality in T-wave

Improving the knowledge and Practices of the residents has a significant impact on the quality of care provided by them. this study was conducted with the aim of determining the knowledge and practice of Residents of Bushehr Province Regarding Risk factors of cardiovascular diseases and their prevention strategies in Bushehr province in 2016.Practice.

This is a descriptive-analytical cross-sectional study. The researched population was the Residents in the health centers of Bushehr province (391 people) who were included in the study by census method.  The demographic information, knowledge, and practices questionnaires were used by the self-report method. After entering the SPSS 19 statistical software, the data were analyzed using Descriptive and analytical tests (Mann-Whitney, Kruskal-Wallis, and Pearson correlation coefficient).

The Results showed that 62.42% (244 people) people had good knowledge, 35.54% (139 people) had average knowledge, and 2.04% (8 people) had poor knowledge. Also, most of the people had good performance, 86.68% (338 people), 10.74% (42 people) had average performance, and 2.58% (11 people) had poor performance. The lowest and highest knowledge and practice are in the area of (smoking and blood pressure) and (smoking and diabetes).

Our study showed that the average score of the knowledge and practices of residents regarding the control of cardiovascular disease is higher than the average score. Considering the priority of educational needs in the field of knowledge and practices, which is related to the knowledge of Residents about the risk factor of tobacco and the Practices of Residents in the field of encouraging patients to be more physically active, Therefore, it is recommended to design and implement retraining courses for the prevention of cardiovascular diseases and the risk factors.

Metabolic syndrome is characterized by a cluster of symptoms including insulin resistance, blood pressure, abdominal obesity, defects in glucose metabolism, and dyslipidemia. Considering the increasing prevalence of cardiovascular diseases and metabolic syndrome, the aim of the present study was to investigate the relationship between metabolic syndrome and its criteria with cardiovascular diseases.

The present study was a case-control study that utilized the results of the enrollment phase of the Tabari cohort study. The case group (304 individuals) was randomly selected from participants with cardiovascular diseases (564 individuals). The control group (304 individuals) was randomly selected from among other participants who were matched by age and sex. The comparison of variables between the two groups was done using the chi-square test. Logistic regression test was used to adjust the effect of confounding variables.

Patients with metabolic syndrome were 69.1% (210) in the case group and 55.6% (169) in the control group (P=0.001). The results of the univariate regression test showed that the chance of developing metabolic syndrome in people with cardiovascular diseases was 1.755 times more than people without cardiovascular diseases (95% CI: 1.280-2.418, and P=0.01). Among the diagnostic criteria of metabolic syndrome, the chances of high blood pressure, high triglyceride levels, and decreased HDL were significantly higher in the case group compared to the control group.

The risk of metabolic syndrome is significantly higher in people with cardiovascular diseases compared to the ones without cardiovascular diseases. After adjusting for confounding factors, we found a significant difference between triglyceride level and blood pressure in the two groups.

The most common problems reported by callers to pre-hospital emergency centers is chest pain. Cardiovascular diseases are among common diseases with serious consequences that have a great impact on the death and lifestyle of sufferers. In this study, the time interval of the arrival of dispatch code to the scene at the bedside of patients who died with heart complaints in the year 2021 in Ahvaz city, Iran is investigated.

The present study is a descriptive-cross-sectional study. Sampling was done by census method and it included all the registered cases of patients who died with heart complaints in emergency center 115 of Ahvaz city, Iran. Data collection was done using a checklist consisting of two sections, including demographic characteristics and time recording. The resulting data was analyzed using SPSS version 21 software.

In this study, the data of 293 patients with an average and standard deviation age of 73.3±17.5 were included in the study. 66.2% were men and the rest were women. The average time to reach the patient's bedside was 7.2 and the time for stopping the medical emergency at the scene was 11.5 minutes, which was not significantly different from the standard value (P<0.05)

Although in the present study, the medical emergency arrived at the patient's bedside in less time than the standard, but unfortunately all the patients had died. The faster arrival of the pre-hospital emergency at the patient's bedside, as one of the most important factors affecting mortality, can be the chance of survival. Increase patient stay.

The present study was conducted with the aim of reviewing the role of serum albumin in heart failure.

Heart failure is a complex clinical syndrome that affects a large population worldwide yearly, and its mortality is even higher than that of many cancers. Although the identification of traditional risk factors has helped in primary prevention, the death rate due to this disease is still increasing. Identifying potential and modifiable risk factors that are not known yet seems necessary in this situation. Serum albumin has been known for many years as a strong prognostic biomarker in many pathological conditions. In recent years, studies have been conducted regarding the role of serum albumin in the prediction, prognosis and treatment of heart failure symptoms.

This narrative study was conducted in 2023. For this purpose, the data bases, PubMed, Scopus, Web of Sciences, SID, MagIran were searched out with the keywords albumin, heart failure, diastolic failure, systolic failure, and a total of 30 articles were included in the study.

Hypoalbuminemia is a common finding in patients with heart failure, and among its main causes in heart failure are malnutrition, inflammation, lack of intestinal function, lack of kidney function, and liver disease. According to clinical and experimental evidence, hypoalbuminemia is related to fluid retention and exacerbation of pulmonary edema in these patients. Also, hypoalbuminemia can independently predict the onset of a new heart failure and can be measured as a prognostic factor of heart failure outcomes. However, there is still no evidence that directly shows the benefit of albumin injection in patients with heart failure.

Serum albumin can be measured as a modifiable risk factor and a prognostic factor in heart failure, but it is necessary to limit its use to cases where its effectiveness has been confirmed.