Inspiratory muscle weakness in cardiovascular diseases: Implications for cardiac rehabilitation

Post-Myocardial Infarction Rehabilitation: The Absence in the Rehabilitation Process of the Diaphragm Muscle

Myocardial infarction (MI) is one of the leading causes of death worldwide. There can be many reasons that cause MI, such as a sedentary lifestyle, a disordered diet, harmful habits such as smoking and alcoholism, concomitant congenital or acquired systemic pathologies. Patients who survive the acute event suffer a functional alteration of multiple body systems. The various cardiology associations recommend starting a rehabilitation process, pursuing the main objective of improving the patient's health status. A negative consequence that can be linked to MI is the dysfunction of the main breathing muscle, the diaphragm. The diaphragm is essential not only for respiratory mechanisms but also for adequate production of cardiac pressures. Post-MI patients present a reduction in the performance of the diaphragm muscle, and this condition can become a risk factor for further relapses or for the onset of heart failure. The article reviews the rehabilitation path for post-MI patients, to highlight the absence given to the diaphragm in the recovery of the patient's health status. The text reviews the post-MI diaphragmatic adaptation to highlight the importance of including targeted training for the diaphragm muscle in the rehabilitation process.

Diaphragmatic dysfunction is associated with postoperative pulmonary complications in the aged patients underwent radical resection of esophageal cancer: a prospective observational study

Background

Diaphragmatic dysfunction escalates the susceptibility to postoperative pulmonary complications (PPCs). Currently, no study reports the occurrence of diaphragmatic dysfunction correlated with PPCs following radical resection of esophageal cancer in aged patients. We aimed to diagnose diaphragmatic dysfunction via ultrasonography and analyze diaphragmatic dysfunction's relation with PPCs after radical resection of esophageal cancer surgery in aged patients.

Methods

This prospective observational study comprised 86 aged patients undergoing radical resection of esophageal cancer. Patient characteristics data and intraoperative details were collected. Ultrasonography was performed before (preoperative) and after (first, third, and fifth day postoperatively) surgery. Outcome measures included PPCs within seven days postoperative, occurrence of diaphragmatic dysfunction, and short-term prognosis.

Results

After excluding 14 patients, we finally analyzed clinical data from 72 patients. The prevalence of PPCs was higher in the patients with diaphragmatic dysfunction than those without (19 of 23, 83% vs. 21 of 49, 43%, P=0.004). Postoperative diaphragmatic dysfunction was positively correlated with PPCs in patients who underwent elective radical esophageal cancer surgery (r=0.37, P=0.001). Persistent diaphragmatic dysfunction, furthermore, was positively correlated with the development of multiple PPCs (r=0.43, P<0.001). The logistic regression analysis revealed that age, total open procedure, and postoperative diaphragmatic dysfunction were identified as significant risk factors for PPCs, while total open procedure was an independent risk factor for diaphragmatic dysfunction.

Conclusions

Postoperative diaphragmatic dysfunction positively correlates with developing PPCs. Continuous monitoring of postoperative diaphragmatic function can screen high-risk patients with PPCs, which has specific clinical significance. Age, total open procedure, and diaphragmatic dysfunction are identified as risk factors for developing PPCs, while total open procedure specifically increases the risk for postoperative diaphragmatic dysfunction.

The Rehabilitation Efficacy of the Novel Metronomic Breathing Technique for Gerontic Patients After Percutaneous Coronary Intervention for Acute Myocardial Infarction-A Pilot Study

Background

The respiratory rehabilitation technique is a crucial component of early cardiac recovery in geriatric patients with acute myocardial infarction (AMI). This study primarily investigated the effectiveness of a novel respiratory rehabilitation technique, metronomic breathing (MB), on geriatric patients after percutaneous coronary intervention for AMI and compliance with home-based rehabilitation compared to traditional respiratory rehabilitation.

Methods

From June 2022 to March 2023, 75 acute myocardial infarction (AMI) patients admitted to the Shanghai Tenth People's Hospital Cardiovascular Department were consecutively enrolled. Ultimately, 46 patients completed the follow-up in this study-26 in the MB group and 20 in the control group-who underwent the novel MB technique and conventional abdominal breathing training. The primary endpoint of the study was left ventricular function measured by noninvasive hemodynamics three months after discharge. The secondary endpoints were compliance and quality of life after three months of home rehabilitation.

Results

After the intervention, several cardiac functional parameters (SV, SVI, CO, CI, LCW, and LCWI), myocardial contractility parameters (VI), and systemic vascular resistance parameters (SVR and SVRI) were significantly greater in the MB group than in the preintervention group (P < 0.05). Furthermore, post-treatment, the MB group exhibited greater SV, SVI, CO, CI, and VI; lower SVR, SVRI, and SBP; and a lower readmission rate three months later than did the control group. The SF-36 scores after three months of MB intervention, PE, BP, GH, VT, SF, RE, and MH, were all significantly greater than those before treatment (P < 0.05). Moreover, the MB group displayed greater compliance with home-based cardiac rehabilitation (P < 0.05).

Conclusion

Compared to conventional respiratory rehabilitation training methods, short-term metronomic respiratory therapy is more effective for reducing systemic vascular resistance, enhancing left ventricular ejection function, enhancing quality of life, and increasing home-based rehabilitation compliance in geriatric patients following AMI with PCI.

Inspiratory muscle endurance is similarly reduced in the early and late stages of chronic Chagas heart disease

OBJECTIVE

Inspiratory muscle strength (IMS) appears to be reduced in subjects with chronic Chagas heart disease (CHD), especially in the presence of heart failure (HF). However, only one study about IMS and inspiratory muscle endurance (IME) in those with CHD without heart failure is available. This study aimed to compare IMS and IME in subjects with CHD in the presence and absence of HF.

METHODS

This is a cross-sectional study in which 30 CHD adult patients were divided into CHD-CC group (initial phase of CHD, without HF; n = 15) and CHD-HF group (advanced phase of CHD, with HF; n = 15). We assessed IMS by maximum inspiratory pressure (MIP) and IME by incremental (Pthmax) and constant load (TLim) tests. Reduced IMS and IME were considered by predicted MIP values <70% and Pthmax/MIP <75%, respectively.

RESULTS

Inspiratory muscle weakness (IMW) was more frequent in CHD-HF than in CHD-CC (46.7% vs. 13.3%; p = 0.05), and both groups had high frequencies of reduced IME (93.3% CHD-CC vs. 100.0% CHD-HF; p = 0.95). Age-adjusted logistic regression analysis using HF as a dependent variable showed that HF was associated with an increased chance of IMW compared with the CHD-CC group (OR = 7.47; p = 0.03; 95% CI 1.20-46.19).

CONCLUSION

This study suggests that, in patients with CHD, HF is associated with IMW, and that reduction of IME is already present in the initial phase, similar to the advanced phase with HF.

Improving Respiratory Muscle Strength and Overall Function in Patients With Cardiovascular Disease Through Rehabilitation Hospitals

Background

The prevalence of respiratory sarcopenia and its effect on respiratory muscle strength (RMS) in patients with cardiovascular disease (CVD), who are transferred to a convalescent rehabilitation hospital after acute care and require continuous cardiac rehabilitation (CR), is currently unclear. This study aimed to assess changes in RMS, physical function, and activities of daily living (ADL) before and after CR performed in a rehabilitation hospital.

Methods

Of 50 consecutive patients transferred to a rehabilitation hospital for ongoing CR, 30 fulfilled the inclusion criteria. Maximal inspiratory and expiratory pressures (MIP and MEP, respectively) were measured at transfer, and patients with decreased RMS were diagnosed with respiratory sarcopenia. RMS, physical function, exercise tolerance, ADL ability, and health-related quality of life (HR-QoL) were measured and compared at transfer and discharge.

Results

The prevalence of respiratory sarcopenia at the time of transfer to the rehabilitation hospital was 93.3%. RMS assessments at transfer and discharge demonstrated significant improvements in %MIP (from 46.3±26.1% to 63.6±33.7%) and %MEP (from 44.8±17.3% to 56.6±21.8%). Short physical performance battery, gait speed, handgrip strength, and knee extension muscle strength significantly improved, along with significant prolongation of 6-min walking distance as a measure of exercise tolerance. ADL assessment using the functional independence measure revealed significant improvement, as did HR-QoL assessed according to the five-dimension, five-level, EuroQoL instrument, following CR.

Conclusions

Although respiratory sarcopenia was highly prevalent among patients with CVD who required transfer to a rehabilitation hospital after acute care, continuous CR significantly improved RMS, ADL, physical function, and exercise tolerance. These findings support the continued expansion of CR, particularly in dedicated rehabilitation hospitals.

Cancer survivor inspiratory muscle training: systematic review and Bayesian meta-analysis

BACKGROUND

The long-term impact of cancer treatment is associated with respiratory dysfunction and physical fitness impairment. Although inspiratory muscle training (IMT) has been shown as an effective exercise therapy in cancer survivors, there is no evidence on the optimal dose, application moment nor specific population effects of this intervention. The main objective of this meta-analysis is to analyse the effects of IMT on pulmonary function, physical fitness and quality of life (QoL) in cancer survivors.

METHODS

This systematic review and meta-analysis was preregistered in the International Prospective Register of Systematic Reviews (PROSPERO) register and conducted according to the Preferred Reporting for Systematic Reviews and Meta-analysis statement. We used a Bayesian multilevel random-effects meta-analysis model to pool the data. Multilevel metaregression models were used to examine the conditional effects of our covariates. Convergence and model fit were evaluated through specific model parameters. Sensitivity analyses removing influential cases and using a frequentist approach were carried out.

RESULTS

Pooled data showed that IMT intervention is effective to improve pulmonary function (standardised mean difference=0.53, 95% credible interval 0.13 to 0.94, SE=0.19). However, IMT did not present statistically significant results on physical fitness and QoL. Metaregression analyses found that the type of cancer, the moment of application and the evaluation tool used had significant moderation effects on pulmonary function.

CONCLUSION

IMT could be an important part in the management of side effects suffered by cancer survivors. Considering the current evidence, this intervention is highly recommended in patients diagnosed with oesophageal and lung cancers. IMT may provide superior benefits before the biological treatment and after the surgery.

PROSPERO REGISTRATION NUMBER

304909.

Symptoms Arising From the Diaphragm Muscle: Function and Dysfunction

There can be many reasons that damage the function of the diaphragm, either transiently or permanently, involving one hemilate or both muscle portions. The diaphragm is associated only with breathing, but many other functions are related to it. The patient is not always aware of the presence of diaphragmatic dysfunction, and it is not always immediate to identify non-respiratory diaphragmatic symptoms. Pseudoanginal pain, night sweats, difficulty memorizing, or muscular and visceral problems of the pelvic floor are just some of the disorders linked to reduced diaphragmatic contractility. A decline in respiratory contractile force can be the basis for further pathological conditions that can increase the rate of mortality and morbidity. The article reviews the possible symptoms that may be presented by the patient, which are not necessarily related to lung function.

Cardiac transplant and exercise cardiac rehabilitation

Cardiac transplantation is the final therapeutic option for patients with end-stage heart failure. Most patients experience a favorable functional ability post-transplant. However, episodes of acute rejection, and multiple comorbidities such as hypertension, diabetes mellitus, chronic kidney disease and cardiac allograft vasculopathy are common. The number of transplants has increased steadily over the past two decades with 3,817 operations performed in the United States in 2021. Patients have abnormal exercise physiologic responses related to surgical cardiac denervation, diastolic dysfunction, and the legacy of reduced skeletal muscle oxidative capacity and impaired peripheral and coronary vasodilatory reserve resulting from pre-transplant chronic heart failure. Cardiorespiratory fitness is below normal for most patients with a mean peak VO2 of approximately 60% of predicted for healthy persons. Cardiac transplant recipients are therefore excellent candidates for Exercise-Based Cardiac Rehabilitation (CR). CR is safe and is a recommendation of professional societies both before (pre-rehabilitation) and after transplantation. CR improves peak VO2, autonomic function, quality of life, and skeletal muscle strength. Exercise training reduces the severity of cardiac allograft vasculopathy, stroke risk, percutaneous coronary intervention, hospitalization for either acute rejection or heart failure, and death. However, there are deficits in our knowledge regarding CR for women and children. In addition, the use of telehealth options for the provision of CR for cardiac transplant patients requires additional investigation.

Consequences of group III/IV afferent feedback and respiratory muscle work on exercise tolerance in heart failure with reduced ejection fraction

Exercise intolerance and exertional dyspnoea are the cardinal symptoms of heart failure with reduced ejection fraction (HFrEF). In HFrEF, abnormal autonomic and cardiopulmonary responses arising from locomotor muscle group III/IV afferent feedback is one of the primary mechanisms contributing to exercise intolerance. HFrEF patients also have pulmonary system and respiratory muscle abnormalities that impair exercise tolerance. Thus, the primary impetus for this review was to describe the mechanistic consequences of locomotor muscle group III/IV afferent feedback and respiratory muscle work in HFrEF. To address this, we first discuss the abnormal autonomic and cardiopulmonary responses mediated by locomotor muscle afferent feedback in HFrEF. Next, we outline how respiratory muscle work impairs exercise tolerance in HFrEF through its effects on locomotor muscle O2 delivery. We then discuss the direct and indirect evidence supporting an interaction between locomotor muscle group III/IV afferent feedback and respiratory muscle work during exercise in HFrEF. Last, we outline future research directions related to locomotor and respiratory muscle abnormalities to progress the field forward in understanding the pathophysiology of exercise intolerance in HFrEF. NEW FINDINGS: What is the topic of this review? This review is focused on understanding the role that locomotor muscle group III/IV afferent feedback and respiratory muscle work play in the pathophysiology of exercise intolerance in patients with heart failure. What advances does it highlight? This review proposes that the concomitant effects of locomotor muscle afferent feedback and respiratory muscle work worsen exercise tolerance and exacerbate exertional dyspnoea in patients with heart failure.

Practical guidelines for exercise prescription in patients with chronic heart failure

Chronic heart failure (HF) is a major cause of morbidity, mortality, disability, and health care costs. A hallmark feature of HF is severe exercise intolerance, which is multifactorial and stems from central and peripheral pathophysiological mechanisms. Exercise training is internationally recognized as a Class 1 recommendation for patients with HF, regardless of whether ejection fraction is reduced or preserved. Optimal exercise prescription has been shown to enhance exercise capacity, improve quality of life, and reduce hospitalizations and mortality in patients with HF. This article will review the rationale and current recommendations for aerobic training, resistance training, and inspiratory muscle training in patients with HF. Furthermore, the review provides practical guidelines for optimizing exercise prescription according to the principles of frequency, intensity, time (duration), type, volume, and progression. Finally, the review addresses common clinical considerations and strategies when prescribing exercise in patients with HF, including considerations for medications, implantable devices, exercise-induced ischemia, and/or frailty.

Visualization Analysis of Research Trends and Hotspots in Inspiratory Muscle Training

BACKGROUND Inspiratory muscle training (IMT) aims to train inspiratory muscles based mainly on the diaphragm by applying a load resistance during the inspiratory process. Many papers related to IMT have been published in various journals; however, no articles objectively and directly present the development trends and research hotspots of IMT. Therefore, this study used CiteSpace to visually analyze recent IMT-related publications to provide valuable information for future IMT-related studies. MATERIAL AND METHODS CiteSpace was applied to analyze the IMT-related publications by countries, institutions, journals, authors, references, and keywords. RESULTS We included 504 papers. The number of IMT-related publications trended upward between 2009 and 2022. Leuven had the highest number of publications by an institution. The American Journal of Respiratory and Critical Care Medicine was the most frequently co-cited journal. Half of the top 10 references cited were from Journal Citation Reports (JCR) Q1 and half were about the application of IMT in chronic obstructive pulmonary disorder. Gosselink was the author with the highest number of publications and Aldrich was the author with the highest co-citation frequency. The preponderance of studies on the surgical population and postoperative pulmonary complications reflects potential application of IMT in enhanced recovery after surgery. CONCLUSIONS This study provides scholars with important information related to IMT research. It analyzes IMT research trends and status, which can help researchers identify primary topics in the field and find ways to explore new research directions to promote the application of IMT in clinical practice and the cooperation of IMT-related disciplines.

The effects of inspiratory muscle training on balance and functional mobility: a systematic review

INTRODUCTION

Inspiratory muscle training (IMT) has been widely used in both healthy and diseased populations especially in older adults, and its effects have been proven not only on inspiratory muscle strength but also on dyspnea, exercise capacity, quality of life, and other health parameters.

AIM

This study aims to review the effects of IMT on balance and functional ability of healthy and diseased populations.

METHODS

A systematic literature search was conducted on MEDLINE, EMBASE, AMED, and Cochrane Central Register of Controlled Trials (CENTRAL). Randomized control trials having participants > 18 years of age and having balance and functional mobility as primary or secondary outcomes were included. Two independent reviewers screened studies against the eligibility criteria, extracted the data, and assessed the quality of evidence. The protocol was prospectively registered on PROSPERO: CRD42021261652.

RESULTS

Ten studies were included in the review out of which eight had balance and six had functional mobility as an outcome measure. There was a significant improvement in balance of the participants after treatment with IMT, however the effect on functional mobility was inconclusive.

CONCLUSION

The review provided evidence of improvement in balance and functional mobility following inspiratory muscle training in both healthy and diseased adults. Future studies should be conducted to determine the optimal protocol and dosage of treatment.

Effectiveness and safety of inspiratory muscle training in patients with pulmonary hypertension: A systematic review and meta-analysis

Background

Inspiratory muscle training (IMT) is a simple and well-tolerated physical therapy that increases respiratory muscle strength and relieving the degree of dyspnea and fatigue. Therefore, it may be used as a transitional modality before exercise training or as a specific physical therapy intervention for those who are diagnosed with respiratory muscle weakness. However, the current evidence on IMT in pulmonary hypertension (PH) patients is inconclusive. The purpose of this systematic review and meta-analysis was to summarize the current role of IMT in this group of patients.

Methods

PubMed, EMBASE, and Cochrane databases were searched through May 2022. Trials examining the feasibility and effectiveness of IMT in PH patients. Outcome measures included adverse events, training adherence and compliance, maximum inspiratory pressure (MIP), maximum expiratory pressure (MEP), forced vital capacity (FVC%), forced expiratory volume in 1 s (FEV1%), FEV1/FVC%, 6 min walk distance (6MWD), Peak VO2, dyspnea, and fatigue perception after the IMT training program. Only randomized controlled trials were included. The Cochrane Risk of Bias tool for controlled trials was adopted to assess study quality. Statistical heterogeneity was evaluated with the chi-square test and I 2 statistic. Mean differences and 95% confidence intervals (CIs) were estimated.

Results

We ultimately identified four studies that met the criteria. These studies comprised 80 patients with 16 males and 64 females. The mean age was 53.25. The main types of PH were group I (pulmonary arterial hypertension, 95%) and group IV (chronic thromboembolic PH, 5%). No severe adverse events were reported in the included studies. IMT had a significant effect on improving MIP (18.89 cmH2O; 95% CI: 9.43-28.35, P < 0.001) and MEP (8.06 cmH2O; 95% CI: 2.39-13.73; P = 0.005), increase in the 6MWD (30.16 m; 95% CI: 1.53-58.79; P = 0.04). No significant improvement was found in pulmonary function (P > 0.05), and uncertain effect on the quality of life (QoL) score.

Conclusion

Based on currently limited evidence, IMT is an effective physical therapy for increasing respiratory muscle function and exercise capacity, but still a lack of evidence on dyspnea and fatigue levels, pulmonary function, and QoL in PH patients. There are reasons to believe that IMT is a promising intervention in PH patients, enriching rehabilitation options and serving as a bridge before formal exercise training. It is expected that IMT will play an important role in the future clinical pathway of physical therapy for this group of patients.

Systematic review registration

[https://www.crd.york.ac.uk/PROSPERO/logout.php], identifier [CRD42022335972].

Inspiratory and leg muscle blood flows during inspiratory muscle metaboreflex activation in heart failure with preserved ejection fraction

The purpose of this study was to determine the cardiovascular consequences elicited by activation of the inspiratory muscle metaboreflex in patients with heart failure with preserved ejection fraction (HFpEF) and controls. Patients with HFpEF (n = 15; 69 ± 10 yr; 33 ± 4 kg/m2) and controls (n = 14; 70 ± 8 yr; 28 ± 4 kg/m2) performed an inspiratory loading trial at 60% maximal inspiratory pressure (PIMAX) until task failure. Mean arterial pressure (MAP) was measured continuously. Near-infrared spectroscopy and bolus injections of indocyanine green dye were used to determine the percent change in blood flow index (%ΔBFI) from baseline to the final minute of inspiratory loading in the vastus lateralis and sternocleidomastoid muscles. Vascular resistance index (VRI) was calculated. Time to task failure was shorter in HFpEF than in controls (339 ± 197 s vs. 626 ± 403 s; P = 0.02). Compared with controls, patients with HFpEF had a greater increase from baseline in MAP (16 ± 7 vs. 10 ± 6 mmHg) and vastus lateralis VRI (76 ± 45 vs. 32 ± 19%) as well as a greater decrease in vastus lateralis %ΔBFI (-32 ± 14 vs. -17 ± 9%) (all, P < 0.05). Sternocleidomastoid %ΔBFI normalized to absolute inspiratory pressure was higher in HFpEF compared with controls (8.0 ± 5.0 vs. 4.0 ± 1.9% per cmH2O·s; P = 0.03). These data indicate that patients with HFpEF exhibit exaggerated cardiovascular responses with inspiratory muscle metaboreflex activation compared with controls.NEW & NOTEWORTHY Respiratory muscle dysfunction is thought to contribute to exercise intolerance in heart failure with preserved ejection fraction (HFpEF); however, the underlying mechanisms are unknown. In the present study, patients with HFpEF had greater increases in leg muscle vascular resistance index and greater decreases in leg muscle blood flow index compared with controls during inspiratory resistive breathing (to activate the metaboreflex). Furthermore, respiratory muscle blood flow index responses normalized to pressure generation during inspiratory resistive breathing were exaggerated in HFpEF compared with controls.

Exercise Training and Interventions for Coronary Artery Disease

Coronary artery disease (CAD) may be considered a main cause of mortality and the prevalence of CAD is increasing nowadays, leading to high health costs in many countries. Despite the fact of the regression of the atherosclerotic plaque, the decrease in blood viscosity and the growth of collateral vessels have been proposed as improvements that CAD patients may obtain under exercise performance. Thus, the present narrative review aimed to carry out a brief specific analysis of the results achieved when performing endurance, strength or inspiratory muscle training. Exercise attenuates certain pathophysiological processes of this disease, such as endothelial dysfunction or the vulnerability of atherosclerotic plaques, and produces improvements in functional capacity and muscle strength, among others. Within the different exercise modalities, the most important parameter to be considered seems to be the total caloric expenditure, and not so much the modality itself. As such, in cardiac rehabilitation, when prescribing exercise, we should possibly focus on the modality that obtains more adherence in patients. To conclude, it must be highlighted that total caloric expenditure is not being taken into account when comparing interventions and this relevant information should be considered in future studies.