Left ventricular diastolic dysfunction and E/E' ratio as the strongest echocardiographic predictors of reduced exercise capacity after acute myocardial infarction

Potential of 68Ga-FAPI-04 PET/MR to predict worsening renal function after acute ST-elevation myocardial infarction

PURPOSE

The fibroblast activation protein inhibitor-04 (FAPI-04) specifically binds to the FAP of activated myocardial fibroblasts, which makes 68Ga-labelled FAPI-04 (68Ga-FAPI-04) positron emission tomography (PET)/magnetic resonance (MR) a new potential imaging technique for the evaluation of myocardial fibrosis. This study aimed to evaluate the potential value of 68Ga-FAPI-04 PET/MR in assessing and predicting changes in renal function in patients with acute ST-elevation myocardial infarction (STEMI).

METHODS

Thirty-three patients with STEMI were included in this study. 68Ga-FAPI-04 PET/MR and cardiac magnetic resonance were performed before discharge in all patients. Worsening renal function(WRF) was defined as ≥20% decrease in estimated glomerular filtration rate(eGFR) from baseline to 12 months.

RESULTS

The WRF group demonstrated higher 68Ga-FAPI-04 uptake volume (UV) at baseline than the non-WRF group(P = 0.009). 68Ga-FAPI-04 UV at baseline was correlated with follow-up eGFR (r = -0.493, P = 0.004). 68Ga-FAPI-04 UV at baseline was a significant predictor of WRF (OR = 1.014, P = 0.029) at 12 months after STEMI.

CONCLUSIONS

As an effective tool to non-invasively quantify myocardial fibroblast activation, 68Ga-FAPI-04 PET/MR has potential value for assessing and predicting worsening renal function in patients with STEMI.

Investigation of Skeletal Muscle Indices Affecting Anaerobic Thresholds after Acute Myocardial Infarction

OBJECTIVE

To investigate skeletal muscle indices influencing the anaerobic threshold (AT) measured by cardiopulmonary exercise testing (CPX).

METHODS

This study included 125 consecutive men (median age: 66.0 years) diagnosed with acute myocardial infarction who underwent CPX before discharge. Participants were categorized into two groups based on their AT: the AT-lowering and AT-maintaining groups, comprising those with AT <11 and ≥11 ml/min/kg, respectively. Skeletal muscle indices that influenced AT, strengths of such influences, and respective cutoff values were investigated using multiple logistic regression analysis, decision-tree analysis, and the random-forest method. Skeletal muscle indices included grip strength, knee extension strength, lower-limb skeletal muscle index, phase angle (PhA), lower-limb PhA, arm circumference (AC), and calf circumference.

RESULTS

Lower-limb PhA, AC, age, and body mass index (BMI) influenced AT (model X2 test: p <0.05; Hosmer-Lemeshow test: p = 0.98). Among the skeletal muscle indices, Gini impurity reduction was the highest in the lower-limb PhA. The cutoff values for AT were ≥4.0° for BMI <24 kg/m2 and ≥6.4° for BMI ≥24 kg/m2.

CONCLUSION

Lower-limb PhA was the most influential skeletal muscle index affecting AT. PhA measured using body composition analyzers is useful to identify exercise-limiting factors and determine the effectiveness of exercise because it can be easily performed shortly.

Significance of End-Diastolic Forward Flow in Patients With Repaired Tetralogy of Fallot - Its Interaction With the Left Ventricular Property and End Organ Damage

BACKGROUND

Although right ventricular (RV) enlargement may affect RV diastolic dysfunction assessed by end-diastolic forward flow (EDFF) in patients with repaired tetralogy of Fallot (TOF), EDFF may also be modified by left ventricular (LV) hemodynamics. We hypothesized that EDFF is affected by LV hemodynamics, not limited to RV diastolic stiffening.

METHODS AND RESULTS

Among 145 consecutive patients with repaired TOF who underwent catheterization, hemodynamic properties in 47 with consistent EDFF and 75 without EDFF were analyzed. Compared with patients without EDFF, those with EDFF had a large RV volume with a high regurgitant fraction. Although cardiac index and central venous pressure (CVP) were similar, contrast injection augmented CVP and LV end-diastolic pressure (EDP) in patients with vs. those without EDFF, suggesting compromised diastolic reserve. In patients with EDFF, the velocity-time integral (VTI) of EDFF was positively correlated with LVEDP and systemic vascular resistance, in addition to RV EDP. EDFF-VTI was correlated with hepatic venous wedge pressure and markers of hepatic dysfunction. Subanalysis of the older (≥6 years) half of the study cohort revealed that EDFF was associated with bi-atrial enlargement independent of RV volume, highlighting the pronounced role of EDFF on the diastolic property in the aged cohort.

CONCLUSIONS

EDFF-VTI in patients with repaired TOF reflects RV diastolic dysfunction, affected by the left heart system. EDFF-VTI indicates blood stagnation, which may be attributed to end-organ damage.

Cross-sectional associations between questionnaire-measured physical activity and tissue doppler indices of left ventricular diastolic function

BACKGROUND

The prevalence of left ventricular (LV) diastolic dysfunction has been increasing over the past decade, and to date, effective pharmacotherapies that enhance LV diastolic function have not yet been identified. Though some data has demonstrated the beneficial effects of exercise training on LV diastolic function, little is known about the adaptations of diastolic function to daily physical activity (PA). Accordingly, our study aimed to investigate the impact of daily PA on tissue Doppler indices of LV diastolic function.

METHODS

A total of 432 participants were enrolled for clinically indicated echocardiography from July 2019 to July 2020 at Peking University People's Hospital. Participants aged ≥ 18 years were included if they had stable PA in the past six months and normal LV systolic function. A questionnaire was used to collect demographic characteristics, medical history, and daily PA. According to PA Guidelines for Americans, we identified these participants into low-intensity PA (LPA) group and moderate-high-intensity PA (MHPA) group. Propensity score matching (PSM) was performed to match potential confounding factors between the two groups. The clinical characteristics and echocardiographic parameters between LPA group and MHPA group were compared using student's t-test, Mann-Whitney U test, and chi-square test as appropriate.

RESULTS

After matching potential confounding factors using PSM with a 1:3 matching ratio, our final analysis included 86 cases in the MHPA group and 214 cases in the LPA group. All demographic characteristics and comorbidities were statistically similar between the two groups. Compared to the LPA group, the MHPA group showed higher septal e' (7.9 ± 2.9 cm/s versus 7.2 ± 2.6 cm/s, P = 0.047). Other echocardiographic parameters associated with LV diastolic function concerning lateral e' and average E/e', also trended towards improved LV diastolic function in the MHPA group, but failed to reach statistical significance.

CONCLUSIONS

Our study demonstrated that moderate-high-intensity daily PA was associated with improved septal e', suggesting that moderate-high-intensity PA could potentially ameliorate LV diastolic dysfunction.

Development of a prediction model for exercise tolerance decline in the exercise assessment of patients with acute myocardial infarction undergoing percutaneous coronary intervention revascularization in the acute phase

Background

Early cardiopulmonary exercise test (CPET) may predict the prognosis of patients with acute myocardial infarction (AMI) after percutaneous coronary intervention (PCI). However, data from CPET to assess the exercise capacity of patients with AMI PCI are still scarce. This study aimed to evaluate the safety of the CPET and assess the predictors and clinical influence of exercise capacity measured by CPET in patients with AMI within 1 week after PCI.

Methods

A total of 275 patients with AMI who underwent PCI in the acute phase were selected. Reduced exercise capacity was defined as peak oxygen uptake (VO2peak) <16 mL/kg/min. According to VO2peak, patients were divided into a normal exercise tolerance group and a reduced exercise tolerance group. The general clinical conditions were compared between the 2 groups to investigate the safety of CPET and the influencing factors of exercise tolerance. A nomogram model for predicting patients' exercise capacity was further developed. Clinical outcomes were recorded.

Results

The median time of CPET in all patients was 5 days after PCI. Among the 275 patients, exercise tolerance decreased in 90 cases (32.72%). Multivariate logic analysis showed that E/e', age, glycosylated hemoglobin, and estimated glomerular filtration rate (eGFR) were independent predictors of early exercise capacity reduction in these patients. Utilizing the correlation coefficients from pre-assessment clinical and CPET indicators within the logistic regression framework, we constructed a nomogram model to forecast the diminishing exercise tolerance in AMI patients. The predictive accuracy of this model, as indicated by a C-index of 0.771 and an area under the receiver operating characteristic (ROC) curve of 0.771 (95% CI: 0.710-0.832), demonstrates its potential as a robust tool in clinical settings. During a follow-up of 24 months, the incidence of clinical outcomes in patients with low exercise tolerance was significantly higher than that in patients with normal exercise tolerance, among which all-cause mortality and reinfarction were statistically different (P=0.009 and P=0.043).

Conclusions

The reduced exercise capacity in patients with AMI after initial PCI is related to age, diastolic dysfunction, renal function, and blood glucose control, which may lead to poor clinical prognosis. The nomogram prediction model performed well in predicting the declining exercise tolerance of patients with AMI.

Cardioprotection Attributed to Aerobic Exercise-Mediated Inhibition of ALCAT1 and Oxidative Stress-Induced Apoptosis in MI Rats

Cardiolipin (CL) plays a pivotal role in mitochondria-mediated apoptosis. Acyl-CoA: lysocardiolipin acyltransferase 1 (ALCAT1) can accelerate CL reactive oxygen production and cause mitochondrial damage. Although we have demonstrated that aerobic exercise significantly reduced ALCAT1 levels in MI mice, what is the temporal characteristic of ALCAT1 after MI? Little is known. Based on this, the effect of exercise on ALCAT1 in MI rats needs to be further verified. Therefore, this paper aimed to characterize ALCAT1 expression, and investigate the possible impact of exercise on ALCAT1 and its role in fibrosis, antioxidant capacity, and apoptosis in MI rats. Our results indicated that the potential utility of MI increased ALCAT1 expression within 1–6 h of MI, and serum CK and CKMB had significant effects in MI at 24 h, while LDH exerted an effect five days after MI. Furthermore, ALCAT1 expression was upregulated, oxidative capacity and excessive apoptosis were enhanced, and cardiac function was decreased after MI, and aerobic exercise can reverse these changes. These findings revealed a previously unknown endogenous cardiac injury factor, ALCAT1, and demonstrated that ALCAT1 damaged the heart of MI rats, and aerobic exercise reduced ALCAT1 expression, oxidative stress, and apoptosis after MI-induced cardiac injury in rats.

Heart Failure After ST-Elevation Myocardial Infarction: Beyond Left Ventricular Adverse Remodeling

ST-segment elevation myocardial infarction (STEMI) remains a significant source of morbidity and mortality worldwide. Despite advances in treatment leading to a significant reduction in the early complications and in-hospital mortality, a significant proportion of STEMI survivors develop heart failure (HF) at follow-up. The classic paradigm of HF after STEMI is one characterized by left ventricular adverse remodeling (LVAR) and encompasses the process of regional and global structural and functional changes that occur in the heart as a consequence of loss of viable myocardium, increased wall stress and neurohormonal activation, and results in HF with reduced ejection fraction (HFrEF). More recently, however, with further improvements in the treatment of STEMI the incidence and entity of LVAR appear to be largely reduced, yet the risk for HF following STEMI is not abolished and remains substantial, identifying a new paradigm by which patients with STEMI present with HF and preserved EF (HFpEF) characterized by reduction of diastolic or systolic reserve independent of LVAR.

Peri-operative changes in diastolic function and outcomes in congenital aortic valve surgery

Background

The ratio of early diastolic mitral inflow velocity (E) to early diastolic mitral annular tissue velocity (e’), or E/e’, is an echocardiographic measure of left ventricular filling pressure. Peri‐operative changes in E/e’ and association with outcomes have been demonstrated in adults undergoing surgery for aortic stenosis (AS). We sought to explore changes in E/e’ and other diastolic indices in the setting of congenital AS surgery and to assess for association with post‐operative outcomes among children and young adults.

Methods

A retrospective, single‐center study was performed among patients 6 months to 30 years of age who underwent congenital AS surgery from 2006 to 2018. Tissue Doppler indices were collected from pre‐ and post‐operative echocardiograms. Post‐operative outcomes were reviewed.

Results

Sixty‐six subjects with subvalvar (45%), valvar (47%), and supravalvar (8%) AS underwent surgery at a median age of 9.5 years (IQR: 4.0–14.8). Pre‐operatively, the lateral E/e’ ratio was 8.6 (6.7–11.0); 33% had E/e’≥10. Post‐operatively, the lateral e’ decreased to 9.9 cm/s (8.0–11.4), the E/e’ ratio increased to 10.4 (8.3–13.1); and 53% had E/e’≥10 (p‐values < 0.0001, 0.0072, and < 0.001, respectively). Pre‐operative lateral e’ correlated modestly with duration of intubation (ρ = −0.24, p‐value 0.048) and post‐operative lateral e’ correlated modestly with duration of intubation and length of hospital stay (ρ = −0.28 and −0.26, p‐values = 0.02 and 0.04, respectively).

Conclusions

Children and young adults who underwent congenital AS surgery had echocardiographic evidence of diastolic dysfunction pre‐operatively that worsened post‐operatively. Lateral e’ may be a sensitive indicator of impaired ventricular relaxation in these patients and may impact duration of intubation and hospital stay.

Brown adipose tissue prevents glucose intolerance and cardiac remodeling in high-fat-fed mice after a mild myocardial infarction

BACKGROUND

Obesity increases the risk of developing impaired glucose tolerance (IGT) and type 2 diabetes (T2D) after myocardial infarction (MI). Brown adipose tissue (BAT) is important to combat obesity and T2D, and increasing BAT mass by transplantation improves glucose metabolism and cardiac function. The objective of this study was to determine if BAT had a protective effect on glucose tolerance and cardiac function in high-fat diet (HFD) fed mice subjected to a mild MI.

METHODS

Male C57BL/6 mice were fed a HFD for eight weeks and then divided into Sham (Sham-operated) and +BAT (mice receiving 0.1 g BAT into their visceral cavity). Sixteen weeks post-transplantation, mice were further subdivided into ±MI (Sham; Sham-MI; +BAT; +BAT-MI) and maintained on a HFD. Cardiac (echocardiography) and metabolic function (glucose and insulin tolerance tests, body composition and exercise tolerance) were assessed throughout 22 weeks post-MI. Quantitative PCR (qPCR) was performed to determine the expression of genes related to metabolic function of perigonadal adipose tissue (pgWAT), subcutaneous white adipose tissue (scWAT), liver, heart, tibialis anterior skeletal muscle (TA); and BAT.

RESULTS

+BAT prevented the increase in left ventricle mass (LVM) and exercise intolerance in response to MI. Similar to what is observed in humans, Sham-MI mice developed IGT post-MI, but this was negated in +BAT-MI mice. IGT was independent of changes in body composition. Genes involved in inflammation, insulin resistance, and metabolism were significantly altered in pgWAT, scWAT, and liver in Sham-MI mice compared to all other groups.

CONCLUSIONS

BAT transplantation prevents IGT, the increase in LVM, and exercise intolerance following MI. MI alters the expression of several metabolic-related genes in WAT and liver in Sham-MI mice, suggesting that these tissues may contribute to the impaired metabolic response. Increasing BAT may be an important intervention to prevent the development of IGT or T2D and cardiac remodeling in obese patients post-MI.

Determinants of Exercise Capacity Following ST-Elevation Myocardial Infarction (STEMI)

BACKGROUND

Abnormal left ventricular systolic and diastolic function and reduced exercise capacity are associated with worse prognosis following ST-elevation myocardial infarction (STEMI). However, evidence is lacking on the determinants of exercise capacity following STEMI. We sought to determine the impact of systolic and diastolic dysfunction on exercise capacity and outcomes following first-ever STEMI.

METHODS

In a retrospective analysis of 139 consecutive STEMI patients who had a transthoracic echocardiogram following STEMI and completed exercise treadmill testing, the primary outcome was to identify clinical and echocardiographic determinants of exercise capacity, and the secondary outcome was to identify determinants of major adverse cardiac events (MACEs).

RESULTS

Mean number of metabolic equivalents (METs > 8) was used as a cut-off. Age, female sex, anterior infarction, abnormal diastolic function, minimum left atrial indexed volume (LAVI_min) ≥ 18 mL/m², average e', and E/e' were associated with METs ≤ 8, but not left ventricular ejection fraction (LVEF). On multivariate analysis, LAVI_min (OR 4.3, 95%CI 1.3-14.2; p = 0.017), anterior infarction (OR 2.6, 95%CI 1.2-5.9; p = 0.022), and abnormal diastolic function (OR 3.73, 95%CI 1.7-8.4; p = 0.001) were independent predictors of METs ≤ 8. On Kaplan-Meier analysis, METs ≤ 8 (p = 0.01) and abnormal diastolic function (p = 0.04) were associated with MACEs (median follow-up 2.3 years). METs ≤ 8 was an independent predictor of MACEs (HR 3.4, 95%CI 1.2-9.8; p = 0.02).

CONCLUSIONS

Following first-ever STEMI, increased LAVI_min, anterior infarction, and abnormal diastolic function were independent predictors of reduced exercise capacity. Furthermore, reduced exercise capacity was an independent predictor of MACEs. These results highlight important prognostic and therapeutic implications related to abnormal diastolic function in STEMI patients that are distinct from those with LV systolic impairment.

Mechanisms of Exercise Capacity Improvement after Cardiac Rehabilitation Following Myocardial Infarction Assessed with Combined Stress Echocardiography and Cardiopulmonary Exercise Testing

Cardiac rehabilitation (CR) is indicated in all patients after acute myocardial infarction (AMI) to improve prognosis and exercise capacity (EC). Previous studies reported that up to a third of patients did not improve their EC after CR (non-responders). Our aim was to assess the cardiac and peripheral mechanisms of EC improvement after CR using combined exercise echocardiography and cardiopulmonary exercise testing (CPET-SE). The responders included patients with an improved EC assessed as a rise in peak oxygen uptake (VO₂) ≥ 1 mL/kg/min. Peripheral oxygen extraction was calculated as arteriovenous oxygen difference (A-VO₂Diff). Out of 41 patients (67% male, mean age 57.5 ± 10 years) after AMI with left ventricular ejection fraction (LVEF) ≥ 40%, 73% improved their EC. In responders, peak VO₂ improved by 27% from 17.9 ± 5.2 mL/kg/min to 22.7 ± 5.1 mL/kg/min, p < 0.001, while non-responders had a non-significant 5% decrease in peak VO₂. In the responder group, the peak exercise heart rate, early diastolic myocardial velocity at peak exercise, LVEF at rest and at peak exercise, and A-VO₂Diff at peak exercise increased, the minute ventilation to carbon dioxide production slope decreased, but the stroke volume and cardiac index were unchanged after CR. Non-responders had no changes in assessed parameters. EC improvement after CR of patients with preserved LVEF after AMI is associated with an increased heart rate response and better peripheral oxygen extraction during exercise.

Combined use of stress echocardiography and cardiopulmonary exercise testing to assess exercise intolerance in patients treated for acute myocardial infarction

Exercise intolerance after acute myocardial infarction (AMI) is a predictor of worse prognosis, but its causes are complex and poorly studied. This study assessed the determinants of exercise intolerance using combined stress echocardiography and cardiopulmonary exercise testing (CPET-SE) in patients treated for AMI. We prospectively enrolled patients with left ventricular ejection fraction (LV EF) ≥40% for more than 4 weeks after the first AMI. Stroke volume, heart rate, and arteriovenous oxygen difference (A-VO2Diff) were assessed during symptom-limited CPET-SE. Patients were divided into four groups according to the percentage of predicted oxygen uptake (VO2) (Group 1, <50%; Group 2, 50-74%; Group 3, 75-99%; and Group 4, ≥100%). Among 81 patients (70% male, mean age 58 ± 11 years, 47% ST-segment elevation AMI) mean peak VO2 was 19.5 ± 5.4 mL/kg/min. A better exercise capacity was related to a higher percent predicted heart rate (Group 2 vs. Group 4, p <0.01), higher peak A-VO2Diff (Group 1 vs. Group 3, p <0.01) but without differences in stroke volume. Peak VO2 and percent predicted VO2 had a significant positive correlation with percent predicted heart rate at peak exercise (r = 0.28, p = 0.01 and r = 0.46, p < 0.001) and peak A-VO2Diff (r = 0.68, p <0.001 and r = 0.36, p = 0.001) but not with peak stroke volume. Exercise capacity in patients treated for AMI with LV EF ≥40% is related to heart rate response during exercise and peak peripheral oxygen extraction. CPET-SE enables non-invasive assessment of the mechanisms of exercise intolerance.

ApoA-I mimetic does not improve left ventricular diastolic dysfunction in rabbits without aortic valve stenosis

BACKGROUND

We previously demonstrated that high-density lipoprotein (HDL) infusions may improve left ventricular diastolic dysfunction (LVDD) in an aortic valve stenosis (AVS) model. Whether the benefit was direct or mediated by the observed reduction in AVS severity is not clear. Here, we aimed to test the direct effect of an ApoA-I mimetic on LVDD in the absence of AVS.

METHODS

Rabbits were exposed to three different protocols to develop LVDD. First, rabbits were exposed to 0.5% cholesterol-rich diet for an average of 17 weeks. Second, rabbits were subjected to surgical ascending aortic constriction (AAC), to mimic the effect of fixed reduced aortic valve area, and studied after 10 weeks. The third model combined both cholesterol-enriched diet (for 12 weeks) and surgical AAC. The control group consisted of age-matched rabbits under normal diet. After development of LVDD, rabbits were randomized to receive infusions of saline or apoA-I mimetic (25 mg/kg) 3 times per week for 4 weeks. Detailed cardiac structure and function measurements were assessed at baseline and weekly during treatment period. Histological and molecular analyses were performed on LV samples.

RESULTS

In the three models, echocardiographic results showed development of LVDD over time, with preserved LV systolic and aortic valve functions versus controls. ApoA-I mimetic infusions did not significantly improve echocardiographic parameters nor molecular markers of cardiac inflammation, oxidative stress and fibrosis.

CONCLUSION

ApoA-I mimetic therapy did not directly improve LVDD. These results indicate that previously observed changes of LVDD were caused by AVS improvement induced by this treatment.

Six-minute walk test: prognostic value and effects of nebivolol versus placebo in elderly patients with heart failure from the SENIORS trial

BACKGROUND

There is limited information about the 6-min walk test (6MWT) in elderly patients with heart failure. We evaluated 6MWT and the effect of nebivolol on 6MWT from the SENIORS trial.

METHODS AND RESULTS

The SENIORS trial evaluated nebivolol versus placebo on death and hospitalisation in patients aged ≥ 70 years with heart failure. A total of 1982 patients undertook a 6MWT at baseline and 1716 patients at 6 months. Patients were divided into tertiles (≤ 200 m, 201 to ≤ 300 m and > 300 m) and to change in distance walked between baseline and 6 months (< 0 m, 0 to < 30 m and ≥ 30 m). The primary outcome was all-cause mortality and cardiovascular hospital admission. Secondary endpoint was all-cause mortality. Baseline walk distance of ≤ 200 m incurred a greater risk of the primary and secondary outcomes (HR 1.41, CI 95% 1.17-1.69, p < 0.001) and (HR 1.37, CI 95% 1.05-1.78, p = 0.019). A decline in walk distance over 6 months was associated with increased risk of clinical events. Nebivolol had no influence on change in walk distance over 6 months.

CONCLUSIONS

The 6MWT has prognostic utility in elderly patients. Those who walked less than 200 m were at highest risk. Nebivolol had no effect on 6MWT.

Association between the tissue accumulation of advanced glycation end products and exercise capacity in cardiac rehabilitation patients

Background

Advanced glycation end products (AGEs) are associated with aging, diabetes mellitus (DM), and other chronic diseases. Recently, the accumulation of AGEs can be evaluated by skin autofluorescence (SAF). However, the relationship between SAF levels and exercise capacity in patients with cardiovascular disease (CVD) remains unclear. This study aimed to investigate the association between the tissue accumulation of AGEs and clinical characteristics, including exercise capacity, in patients with CVD.

Methods

We enrolled 319 consecutive CVD patients aged ≥40 years who underwent early phase II cardiac rehabilitation (CR) at our university hospital between November 2015 and September 2017. Patient background, clinical data, and the accumulation of AGEs assessed by SAF were recorded at the beginning of CR. Characteristics were compared between two patient groups divided according to the median SAF level (High SAF and Low SAF).

Results

The High SAF group was significantly older and exhibited a higher prevalence of DM than the Low SAF group. The sex ratio did not differ between the two groups. AGE levels showed significant negative correlations with peak oxygen uptake and ventilator efficiency (both P <  0.0001). Exercise capacity was significantly lower in the high SAF group than in the low SAF group, regardless of the presence or absence of DM (P <  0.05). A multivariate logistic regression analysis showed that SAF level was an independent factor associated with reduced exercise capacity (odds ratio 2.10; 95% confidence interval 1.13–4.05; P = 0.02).

Conclusion

High levels of tissue accumulated AGEs, as assessed by SAF, were significantly and independently associated with reduced exercise capacity. These data suggest that measuring the tissue accumulation of AGEs may be useful in patients who have undergone CR, irrespective of whether they have DM.

Reduced exercise capacity and clinical outcomes following acute myocardial infarction

Reduced exercise capacity is known to be an important predictor of poor prognosis and disability in patients with cardiovascular diseases and chronic heart failure, and even members of the general population. However, data about exercise capacity assessed by cardiopulmonary exercise testing (CPX) in acute myocardial infarction (AMI) patients who underwent primary percutaneous coronary intervention (PCI) is scarce. Among 594 consecutive AMI patients who underwent primary PCI, we examined 136 patients (85.3% men, 64.9 ± 11.9 years) who underwent CPX during hospitalization for AMI. CPX was usually performed 5 days after the onset of AMI. Reduced exercise capacity was defined as peak VO₂ ≤ 12. Clinical outcomes including all-cause death, myocardial infarction, and hospitalization due to heart failure were followed. Among 136 patients, reduced exercise capacity (peak VO₂ ≤ 12) was seen in 38 patients (28%). Patients with reduced exercise capacity were older, more likely to have hypertension, and had lower renal function. In echocardiography, patients with reduced exercise capacity had higher E/e' and larger left atrial dimension. Multivariate logistic analysis showed that E/e' (OR 1.19, 95% CI 1.09-1.31, p < 0.001) was an independent predictor of reduced exercise capacity (peak VO₂ ≤ 12). Median follow-up term was 12 months (IQR 9-22). The occurrence of composite endpoints of all-cause death, myocardial infarction, and hospitalization due to heart failure was significantly higher in patients with peak VO₂ ≤ 12 than those with peak VO₂ > 12 (p < 0.001). Reduced exercise capacity following primary PCI in AMI patients is associated with diastolic dysfunction and may lead to poorer clinical outcomes.

Impact of aerobic interval training and continuous training on left ventricular geometry and function: a SAINTEX-CAD substudy

BACKGROUND

Increase of exercise capacity (peak VO₂) after cardiac rehabilitation improves outcome in patients with coronary artery disease (CAD). Systolic and diastolic function have been associated with peak VO₂, but their role towards improvement of exercise capacity remains unclear. It is unknown which exercise intensity has the most beneficial impact on left ventricular (LV) geometry and function in CAD patients without heart failure.

METHODS

200 stable CAD patients without heart failure were randomized to 3months of aerobic interval training (AIT) or aerobic continuous training (ACT). Cardiopulmonary exercise test and transthoracic echocardiography were scheduled before and after 3months of training.

RESULTS

At baseline, a higher peak VO₂ correlated with lower LV posterior wall thickness (p=0.002), higher LV ejection fraction (p=0.008), better LV global longitudinal strain (p=0.043) and lower E/e' (0=0.001). After multivariate stepwise regression analysis only E/é remained an independent predictor of peak VO₂ (p=0.042). Improvement of peak VO₂ after 3months of training correlated with reverse remodeling of the interventricular septum (p=0.005), enlargement of LV diastolic volume (p=0.007) and increase of LV stroke volume (p=0.018) but not with other indices of systolic or diastolic function. Significant reduction of the interventricular septum thickness after cardiac rehabilitation was observed (p=0.012), with a trend towards more reverse remodeling after ACT compared to AIT (p=0.054). In contrast, there were no changes in other parameters of LV geometry, diastolic or systolic function.

CONCLUSION

Systolic and diastolic function are determinants of baseline exercise capacity in CAD patients without heart failure, but do not seem to mediate improvement of peak VO₂ after either AIT or ACT.

Interval exercise training increases LIF expression and prevents myocardial infarction-induced skeletal muscle atrophy in rats

AIMS

Myocardial infarction (MI) is commonly associated with body weight loss and skeletal muscle atrophy. Studies have shown that exercise training could give beneficial effects on skeletal muscle growth. Leukemia inhibitory factor (LIF) is a key regulator of muscle growth and regeneration. The aim of this study was to investigate the effects of interval exercise training (IET) on the expression of LIF and the MI-induced skeletal muscle atrophy.

MAIN METHODS

Male Sprague-Dawley rats were used to establish the MI model by ligation of the left anterior descending coronary artery. Infarcted Rats were divided into two groups: sedentary MI group (MI) and MI with interval exercise group (ME), and compared to sham-operated group (Sham). Exercise-trained animals were subjected to eight weeks of IET. Cardiac function, collagen volume fraction, expression of LIF and its receptor LIFR, myofiber size, apoptosis and proliferation in gastrocnemius muscle were analyzed.

KEY FINDINGS

IET increased heart functional performance and was accompanied with reversing cardiac pathological remodeling. Moreover, IET increased the expression of LIF and LIFR, activated signal transducer and activator of transcription (STAT3), reduced apoptosis and promoted proliferation in gastrocnemius muscle compared with the MI group. In addition, there was a significant negative correlation between skeletal muscle atrophy and LIF expression which was stimulated by IET in infarcted rats.

SIGNIFICANCE

IET reverses MI-induced cardiac dysfunction and skeletal muscle atrophy. In addition, IET up-regulates the expression of muscle LIF/LIFR and activates the STAT3.

Association between baseline cardiovascular mechanics and exercise capacity in patients with coronary artery disease

OBJECTIVE

Functional capacity is one of the cardinal determinants of morbidity and mortality in patients with coronary artery disease (CAD). We hypothesized that baseline cardiovascular mechanics, including cardiac systolic and diastolic functions, arterial mechanics, and ventriculoarterial interaction, may play a role in predicting exercise capacity in patients with CAD.

METHODS

Fifty consecutive patients with CAD who were referred to cardiac rehabilitation were prospectively included in the study. Patients with non-sinus rhythms or severe valvular disease were excluded. Full left ventricular pressure-volume loops were constructed and arterial mechanics was evaluated using echocardiographic and tonometric measurements. Cardiopulmonary exercise tests were performed to measure exercise capacity.

RESULTS

Fifty patients were enrolled in the study. Ventriculo-arterial coupling showed a moderate correlation with peak oxygen consumption (VO2) (r=0.410, p=0.04) in patients with reduced left ventricular ejection fraction (LVEF). Only left ventricular volume at 15 mm Hg (r=0.514, p<0.01) in diastolic parameters (stiffness constant, p=0.75; ventricular compliance, p=0.17) and arterial compliance (r=0.467, p=0.01) in arterial parameters [arterial elastance, p=0.27; systemic vascular resistance, p=0.45; augmentation pressure, p=0.85; augmentation index (AIx), p=0.63; heart rate-corrected AIx, p=0.68] emerged as significant factors correlated with peak VO2 in patients with normal LVEF.

CONCLUSION

Comprehensive evaluation of resting cardiovascular mechanics can give clues about exercise-recruited reserves of the cardiovascular system. Optimization of ventriculo-arterial coupling in patients with reduced LVEF and arterial compliance in patients with normal LVEF should be the main target in patients with CAD and limited functional capacity.

Impaired Diastolic Recovery after Acute Myocardial Infarction as a Predictor of Adverse Events

BACKGROUND

To investigate the impact of left ventricular (LV) diastolic functional recovery on major adverse cardiac events (MACE) 6 months after acute myocardial infarction (AMI) in patients with preserved LV systolic function.

METHODS

A total 463 patients with preserved LV systolic function at 6 months after an AMI were divided into two groups based on the extent of diastolic recovery assessed by echocardiography: group I (n = 241) showed improving diastolic function and group II (n = 222) did not. MACE included death, recurrent myocardial infarction, and rehospitalization due to heart failure, and these events were compared with the patients' characteristics at baseline.

RESULTS

Compared with group I, the patients in group II were older and had a higher prevalence of hypertension and diabetes. Blood levels of hemoglobin and triglyceride were lower in group II, whereas the levels of N-terminal pro-B-type natriuretic peptide (NT-proBNP) and of high-sensitivity C-reactive protein were higher in this group than in group I. MACE were significantly more frequent in group II than in group I. Age, elevated NT-proBNP, and impaired diastolic recovery were significant independent predictors of MACE.

CONCLUSION

Despite improvement in LV systolic function, LV diastolic function had not improved in 222 patients (47.9%) by the 6-month follow-up after the index AMI, and impaired diastolic functional recovery was found to be an independent predictor of MACE. Evaluation of diastolic function would be a useful way to stratify risk in patients discharged after an index AMI.