Effects of cardiac rehabilitation with and without meditation on myocardial blood flow using quantitative positron emission tomography: A pilot study

Meditation for the primary and secondary prevention of cardiovascular disease

BACKGROUND

Interventions incorporating meditation to address stress, anxiety, and depression, and improve self-management, are becoming popular for many health conditions. Stress is a risk factor for cardiovascular disease (CVD) and clusters with other modifiable behavioural risk factors, such as smoking. Meditation may therefore be a useful CVD prevention strategy.

OBJECTIVES

To determine the effectiveness of meditation, primarily mindfulness-based interventions (MBIs) and transcendental meditation (TM), for the primary and secondary prevention of CVD.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, three other databases, and two trials registers on 14 November 2021, together with reference checking, citation searching, and contact with study authors to identify additional studies.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) of 12 weeks or more in adults at high risk of CVD and those with established CVD. We explored four comparisons: MBIs versus active comparators (alternative interventions); MBIs versus non-active comparators (no intervention, wait list, usual care); TM versus active comparators; TM versus non-active comparators.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. Our primary outcomes were CVD clinical events (e.g. cardiovascular mortality), blood pressure, measures of psychological distress and well-being, and adverse events. Secondary outcomes included other CVD risk factors (e.g. blood lipid levels), quality of life, and coping abilities. We used GRADE to assess the certainty of evidence.

MAIN RESULTS

We included 81 RCTs (6971 participants), with most studies at unclear risk of bias. MBIs versus active comparators (29 RCTs, 2883 participants) Systolic (SBP) and diastolic (DBP) blood pressure were reported in six trials (388 participants) where heterogeneity was considerable (SBP: MD -6.08 mmHg, 95% CI -12.79 to 0.63, I2 = 88%; DBP: MD -5.18 mmHg, 95% CI -10.65 to 0.29, I2 = 91%; both outcomes based on low-certainty evidence). There was little or no effect of MBIs on anxiety (SMD -0.06 units, 95% CI -0.25 to 0.13; I2 = 0%; 9 trials, 438 participants; moderate-certainty evidence), or depression (SMD 0.08 units, 95% CI -0.08 to 0.24; I2 = 0%; 11 trials, 595 participants; moderate-certainty evidence). Perceived stress was reduced with MBIs (SMD -0.24 units, 95% CI -0.45 to -0.03; I2 = 0%; P = 0.03; 6 trials, 357 participants; moderate-certainty evidence). There was little to no effect on well-being (SMD -0.18 units, 95% CI -0.67 to 0.32; 1 trial, 63 participants; low-certainty evidence). There was little to no effect on smoking cessation (RR 1.45, 95% CI 0.78 to 2.68; I2 = 79%; 6 trials, 1087 participants; low-certainty evidence). None of the trials reported CVD clinical events or adverse events. MBIs versus non-active comparators (38 RCTs, 2905 participants) Clinical events were reported in one trial (110 participants), providing very low-certainty evidence (RR 0.94, 95% CI 0.37 to 2.42). SBP and DBP were reduced in nine trials (379 participants) but heterogeneity was substantial (SBP: MD -6.62 mmHg, 95% CI -13.15 to -0.1, I2 = 87%; DBP: MD -3.35 mmHg, 95% CI -5.86 to -0.85, I2 = 61%; both outcomes based on low-certainty evidence). There was low-certainty evidence of reductions in anxiety (SMD -0.78 units, 95% CI -1.09 to -0.41; I2 = 61%; 9 trials, 533 participants; low-certainty evidence), depression (SMD -0.66 units, 95% CI -0.91 to -0.41; I2 = 67%; 15 trials, 912 participants; low-certainty evidence) and perceived stress (SMD -0.59 units, 95% CI -0.89 to -0.29; I2 = 70%; 11 trials, 708 participants; low-certainty evidence) but heterogeneity was substantial. Well-being increased (SMD 0.5 units, 95% CI 0.09 to 0.91; I2 = 47%; 2 trials, 198 participants; moderate-certainty evidence). There was little to no effect on smoking cessation (RR 1.36, 95% CI 0.86 to 2.13; I2 = 0%; 2 trials, 453 participants; low-certainty evidence). One small study (18 participants) reported two adverse events in the MBI group, which were not regarded as serious by the study investigators (RR 5.0, 95% CI 0.27 to 91.52; low-certainty evidence). No subgroup effects were seen for SBP, DBP, anxiety, depression, or perceived stress by primary and secondary prevention. TM versus active comparators (8 RCTs, 830 participants) Clinical events were reported in one trial (201 participants) based on low-certainty evidence (RR 0.91, 95% CI 0.56 to 1.49). SBP was reduced (MD -2.33 mmHg, 95% CI -3.99 to -0.68; I2 = 2%; 8 trials, 774 participants; moderate-certainty evidence), with an uncertain effect on DBP (MD -1.15 mmHg, 95% CI -2.85 to 0.55; I2 = 53%; low-certainty evidence). There was little or no effect on anxiety (SMD 0.06 units, 95% CI -0.22 to 0.33; I2 = 0%; 3 trials, 200 participants; low-certainty evidence), depression (SMD -0.12 units, 95% CI -0.31 to 0.07; I2 = 0%; 5 trials, 421 participants; moderate-certainty evidence), or perceived stress (SMD 0.04 units, 95% CI -0.49 to 0.57; I2 = 70%; 3 trials, 194 participants; very low-certainty evidence). None of the trials reported adverse events or smoking rates. No subgroup effects were seen for SBP or DBP by primary and secondary prevention. TM versus non-active comparators (2 RCTs, 186 participants) Two trials (139 participants) reported blood pressure, where reductions were seen in SBP (MD -6.34 mmHg, 95% CI -9.86 to -2.81; I2 = 0%; low-certainty evidence) and DBP (MD -5.13 mmHg, 95% CI -9.07 to -1.19; I2 = 18%; very low-certainty evidence). One trial (112 participants) reported anxiety and depression and found reductions in both (anxiety SMD -0.71 units, 95% CI -1.09 to -0.32; depression SMD -0.48 units, 95% CI -0.86 to -0.11; low-certainty evidence). None of the trials reported CVD clinical events, adverse events, or smoking rates.

AUTHORS' CONCLUSIONS

Despite the large number of studies included in the review, heterogeneity was substantial for many of the outcomes, which reduced the certainty of our findings. We attempted to address this by presenting four main comparisons of MBIs or TM versus active or inactive comparators, and by subgroup analyses according to primary or secondary prevention, where there were sufficient studies. The majority of studies were small and there was unclear risk of bias for most domains. Overall, we found very little information on the effects of meditation on CVD clinical endpoints, and limited information on blood pressure and psychological outcomes, for people at risk of or with established CVD. This is a very active area of research as shown by the large number of ongoing studies, with some having been completed at the time of writing this review. The status of all ongoing studies will be formally assessed and incorporated in further updates.

Exercise-based cardiac rehabilitation for left ventricular function in patients with heart failure: A systematic review and meta-analysis

AIMS

To evaluate the effect of exercise rehabilitation on the left ventricular (LV) function in patients with heart failure (HF).

METHODS

PubMed, Cochrane Library and Embase were searched until May 2023. Randomized controlled trials (RCTs) providing data on changes in LV function, comparing exercise to no-exercise controls with HF of any type, were included.

RESULTS

A total of 16 studies including 1443 participants were included. LV end-diastolic diameter (LVEDD) was significantly improved in the exercise group [mean differences (MD), -2.67; 95 % confidence interval (CI) (-4.88, -0.46); P=0.02], but left atrial volume index (LAVI), left ventricular end-systolic diameter (LVESD), E/e' E/A, end-diastolic volume (EDV), end-systolic volume (ESV), left ventricular ejection fraction (LVEF) and LV mass were unaltered compared to the non-exercise group. High intensity interval training (HIIT) or with moderate exercise (MT) led to improvement in LVEDD [MD, 3.62; 95 %CI (2.55, 4.69); P<0.00001], but not LAVI, E/e' and E/A. Sensitivity and subgroup analyses showed that the location, the type of HF and study duration may be the source of heterogeneity in LVEF. Age appears to be a source of heterogeneity in EDV and ESV. The Egger test indicated no significant publication bias.

CONCLUSIONS

Exercise can partially improve LV function in patients with HF, with improvements appearing to be dependent on study quality, the type of HF, and race. However, there are some indicators that do not seem to improve or are even worse than the control group. Among all exercise modalities, HIIT shows the greatest benefit for HF patients.

Coronary microvascular function in male physicians with burnout and job stress: an observational study

BACKGROUND

As a professional group, physicians are at increased risk of burnout and job stress, both of which are associated with an increased risk of coronary heart disease that is at least as high as that of other professionals. This study aimed to examine the association of burnout and job stress with coronary microvascular function, a predictor of major adverse cardiovascular events.

METHODS

Thirty male physicians with clinical burnout and 30 controls without burnout were included. Burnout was assessed with the Maslach Burnout Inventory and job stress with the effort-reward imbalance and overcommitment questionnaire. All participants underwent myocardial perfusion positron emission tomography to quantify endothelium-dependent (cold pressor test) and endothelium-independent (adenosine challenge) coronary microvascular function. Burnout and job stress were regressed on coronary flow reserve (primary outcome) and two additional measures of coronary microvascular function in the same model while adjusting for age and body mass index.

RESULTS

Burnout and job stress were significantly and independently associated with endothelium-dependent microvascular function. Burnout was positively associated with coronary flow reserve, myocardial blood flow response, and hyperemic myocardial blood flow (r partial = 0.28 to 0.35; p-value = 0.008 to 0.035). Effort-reward ratio (r partial =  - 0.32 to - 0.38; p-value = 0.004 to 0.015) and overcommitment (r partial =  - 0.30 to - 0.37; p-value = 0.005 to 0.022) showed inverse associations with these measures.

CONCLUSIONS

In male physicians, burnout and high job stress showed opposite associations with coronary microvascular endothelial function. Longitudinal studies are needed to show potential clinical implications and temporal relationships between work-related variables and coronary microvascular function. Future studies should include burnout and job stress for a more nuanced understanding of their potential role in cardiovascular health.

LASSO Homotopy-Based Sparse Representation Classification for fNIRS-BCI

Brain-computer interface (BCI) systems based on functional near-infrared spectroscopy (fNIRS) have been used as a way of facilitating communication between the brain and peripheral devices. The BCI provides an option to improve the walking pattern of people with poor walking dysfunction, by applying a rehabilitation process. A state-of-the-art step-wise BCI system includes data acquisition, pre-processing, channel selection, feature extraction, and classification. In fNIRS-based BCI (fNIRS-BCI), channel selection plays a vital role in enhancing the classification accuracy of the BCI problem. In this study, the concentration of blood oxygenation (HbO) in a resting state and in a walking state was used to decode the walking activity and the resting state of the subject, using channel selection by Least Absolute Shrinkage and Selection Operator (LASSO) homotopy-based sparse representation classification. The fNIRS signals of nine subjects were collected from the left hemisphere of the primary motor cortex. The subjects performed the task of walking on a treadmill for 10 s, followed by a 20 s rest. Appropriate filters were applied to the collected signals to remove motion artifacts and physiological noises. LASSO homotopy-based sparse representation was used to select the most significant channels, and then classification was performed to identify walking and resting states. For comparison, the statistical spatial features of mean, peak, variance, and skewness, and their combination, were used for classification. The classification results after channel selection were then compared with the classification based on the extracted features. The classifiers used for both methods were linear discrimination analysis (LDA), support vector machine (SVM), and logistic regression (LR). The study found that LASSO homotopy-based sparse representation classification successfully discriminated between the walking and resting states, with a better average classification accuracy (p < 0.016) of 91.32%. This research provides a step forward in improving the classification accuracy of fNIRS-BCI systems. The proposed methodology may also be used for rehabilitation purposes, such as controlling wheelchairs and prostheses, as well as an active rehabilitation training technique for patients with motor dysfunction.

Effectiveness of Mantra-Based Meditation on Mental Health: A Systematic Review and Meta-Analysis

Background: Meditation is defined as a form of cognitive training that aims to improve attentional and emotional self-regulation. This systematic review aims to evaluate the available scientific evidence on the effectiveness and safety of mantra-based meditation techniques (MBM), in comparison to passive or active controls, or other active treatment, for the management of mental health symptoms. Methods: MEDLINE, EMBASE, Cochrane Library, and PsycINFO databases were consulted up to April 2021. Randomised controlled trials regarding meditation techniques mainly based on the repetition of mantras, such as transcendental meditation or others, were included. Results: MBM, compared to control conditions, was found to produce significant small-to-moderate effect sizes in the reduction of anxiety (g = −0.46, IC95%: −0.60, −0.32; I² = 33%), depression (g = −0.33, 95% CI: −0.48, −0.19; I² = 12%), stress (g = −0.45, 95% CI: −0.65, −0.24; I² = 46%), post-traumatic stress (g = −0.59, 95% CI: −0.79, −0.38; I² = 0%), and mental health-related quality of life (g = 0.32, 95% CI: 0.15, 0.49; I² = 0%). Conclusions: MBM appears to produce small-to-moderate significant reductions in mental health; however, this evidence is weakened by the risk of study bias and the paucity of studies with psychiatric samples and long-term follow-up.

Multimodality molecular imaging: Gaining insights into the mechanisms linking chronic stress to cardiovascular disease

Positron emission tomography (PET) imaging can yield unique mechanistic insights into the pathophysiology of atherosclerosis. 18F-fluorodeoxyglucose (18F-FDG), a radiolabeled glucose analog, is retained by cells in proportion to their glycolytic activity. While 18F-FDG accumulates within several cell types in the arterial wall, its retention correlates with macrophage content, providing an index of arterial inflammation (ArtI) which predicts subsequent cardiovascular disease (CVD) events. Furthermore, 18F-FDG-PET imaging allows the simultaneous assessment of metabolic activity in several tissues (e.g., brain, bone marrow) and is performed in conjunction with cross-sectional imaging that enables multi-organ structural assessments. Accordingly, 18F-FDG-PET/computed tomography (CT) imaging facilitates evaluation of disease pathways that span multiple organ systems. Within this paradigm, 18F-FDG-PET/CT imaging has been implemented to study the mechanism linking chronic stress to CVD. To evaluate this, stress-associated neural activity can be quantified (as metabolic activity of the amygdala (AmygA)), while leukopoietic activity, ArtI, and coronary plaque burden are assessed concurrently. Such simultaneous quantification of tissue structures and activities enables the evaluation of multi-organ pathways with the aid of mediation analysis. Using this approach, multi-system 18F-FDG-PET/CT imaging studies have demonstrated that chronically heightened stress-associated neurobiological activity promotes leukopoietic activity and systemic inflammation. This in turn fuels more ArtI and greater non-calcified coronary plaque burden, which result in more CVD events. Subsequent studies have revealed that common stressors, such as chronic noise exposure and income disparities, drive the front end of this pathway to increase CVD risk. Hence, multi-tissue multimodality imaging serves as a powerful tool to uncover complex disease mechanisms.

New Ultrasound Technologies for Ischemic Heart Disease Assessment and Monitoring in Cardiac Rehabilitation

Owing to its ease of application, noninvasive nature, and safety, echocardiography is an essential imaging modality to assess cardiac function in patients affected by ischemic heart disease (IHD). Over the past few decades, we have witnessed a continuous series of evolutions in the ultrasound field that have led to the introduction of innovative echocardiographic modalities which allowed to better understand the morphofunctional abnormalities occurring in cardiovascular diseases. This article offers an overview of some of the newest echocardiographic modalities and their promising application in IHD diagnosis, risk stratification, management, and monitoring after cardiac rehabilitation.

Coronary vasomotion and exercise-induced adaptations in coronary artery disease patients: A systematic review and meta-analysis

Background:

Exercise can improve coronary blood flow in a healthy heart, but the vascular response of patients with coronary artery disease (CAD) is different. The aim of this study was to systematically review the chronic effects of exercise on coronary arterial function in CAD patients.

Materials and Methods:

Six electronic databases (PubMed, ScienceDirect, “Scopus,” Web of Science, EMBASE, and Google Scholar) covering publications from 1986 to 2019 were systematically searched with related keywords. Studies were included if they investigated changes in blood flow and coronary artery diameter in response to chronic exercise training in patients with CAD. A total of 5421 studies were assessed for quality and outcomes, and finally five studies met criteria for inclusion. For metaanalysis, the results of the studies were pooled using the randomeffects model. The heterogeneity between the studies was checked using I² index.

Results:

The total sample population consisted of 108 CAD patients. According to the findings of this study, coronary artery function in adaptation with exercise showed that a period of exercise leads to statistically significant improvement in coronary flow velocity reserve (z = 3.15, P = 0.002; standardized mean difference [SMD] =2.33, 95% confidence interval [CI]: 0.88–3.78) (containing six trials). In addition, vasodilatory response of coronary arteries in response to endothelium-independent vasodilator nitroglycerin was investigated in three studies (containing four trials). A meta-analysis showed that performing chronic aerobic exercises did not make a significant change in the endothelium-independent vasodilator (z = 0.83, P = 0.40; SMD = −0.36, 95% CI: −1.21–0.49).

Conclusion:

Based on the results of the present study, aerobic exercises improve the endothelial function of coronary arteries and thereby the vascular vasomotion function, while the results of this meta-analysis showed no change in arterial smooth muscle's function by chronic aerobic exercises. This study reflects the lack of high- and medium-quality reports about the chronic effects of anaerobic and resistance exercises and the various methods of aerobic exercise on cardiovascular function.

Disentangling the Links Between Psychosocial Stress and Cardiovascular Disease

Stress is a pervasive component of the human experience. While often considered an adversity to be ignored, chronic stress has important pathological consequences, including cardiovascular disease (CVD). Stress also increases the prevalence and severity of several CVD risk factors, including hypertension, diabetes mellitus, and obesity. Yet even after adjustment, stress' attributable CVD risk is similar to those risk factors, suggesting it is a particularly potent contributor. Nevertheless, there has been insufficient study of mechanisms linking stress to CVD or of methods to attenuate stress' pathological impact. This review covers the current concepts of how stress impacts CVD and emerging approaches to mitigate stress-attributable CVD risk.