Association between arterial stiffness and autonomic dysfunction in participants underwent treadmill exercise testing: a cross-sectional analysis

Data on the impact of arterial stiffness on autonomic function are limited. We sought to investigate whether heart rate recovery (HRR), a predictor of autonomic function, is impaired in patients with increased arterial stiffness. A total of 475 participants (mean age 55.8 ± 11.1 years, 34.3% women) who underwent a treadmill exercise test (TET) for the evaluation of chest pain were retrospectively analyzed. All patients underwent brachial-ankle pulse wave velocity (baPWV) measurement on the same day. HRR was defined as the difference in heart rate from maximal exercise to 1 min of recovery. Participants with the lowest HRR tertile were older and had more cardiovascular risk factors than those with the highest HRR tertile. Simple correlation analysis showed that baPWV was negatively correlated with HRR (r =  - 0.327, P < 0.001). In multiple linear regression analysis, there was a significant association between baPWV and HRR, even after adjusting for potential confounders (β =  - 0.181, P < 0.001). In participants who underwent TET, baPWV was negatively correlated with HRR. The results of our study indicate a potential relationship between arterial stiffness and the autonomic nervous system.

Symptom-limited exercise capacity is associated with long-term survival

The prognostic value of exercise capacity has been demonstrated in subjects with established cardiovascular diseases. We aim to evaluate the independence of exercise capacity measured by treadmill exercise test (TET) in predicting long-term outcomes among various comorbidities. This study was conducted from January 2003 to December 2012 in a tertiary medical center in Taiwan. Subjects referred for symptom-limited TET were recruited. Peak achieved metabolic equivalents (METs) were determined by treadmill grade and speed at peak exercise. The main outcomes were cardiovascular and all-cause mortality by linking to the National Death Registry. A total of 18,954 participants (57.8 ± 12.8 years, 62% men) achieved a mean peak METs of 9.2. Subjects in the lowest tertile of peak METs were older, had poorer renal function, lower hemoglobin, and more comorbidities. During a median follow-up of 4.3 years, there were 642 mortalities and 132 cardiovascular deaths. Peak METs significantly predicted cardiovascular death and all-cause mortality in the multivariable Cox regression models [hazard ratio (95% confidence intervals): 0.788 (0.660-0.940) and 0.835 (0.772-0.903), respectively]. The prognostic influence of peak METs consistently appeared in the subgroups, regardless of age, gender, body weight, comorbidities, use of beta-blockers, or the presence of exercise-induced ischemia. The fitness was more predictive of long-term outcomes in young or those with ischemic changes during TET (P for interaction: 0.035 and 0.018, respectively). The benefit of fitness was nonlinearly associated with long-term survival. The prognostic impacts of exercise capacity were universally observed in subjects with or without various comorbidities.

Exercise-Induced Ischemic ST-Segment Elevation in Anomalous Origin of the Right Coronary Artery From the Left Sinus of Valsalva With an Intramural Course and Blocked Coronary Bypass

Sudden cardiac events in young athletes are a major concern in the field of sports cardiology. Although coronary artery anomalies remain a major cause of cardiac events in young athletes, only a few cases have been diagnosed prior to critical events. Here, we present the case of a previously asymptomatic young male runner who experienced sudden cardiac arrest at the end of a marathon. The patient immediately received cardiopulmonary resuscitation from a bystander and was transported to an emergency hospital. As his electrocardiogram showed ventricular fibrillation, he was treated with electric shock, and his rhythm was successfully converted to a normal sinus rhythm. Following successful resuscitation, the patient was diagnosed with an anomalous origin of the right coronary artery from the left sinus of Valsalva with an intramural course. The patient underwent coronary artery bypass using the right internal thoracic artery. Fifteen years later, the coronary bypass was found to be blocked, but the patient was asymptomatic. However, an exercise electrocardiogram revealed ST-segment elevation in the inferior leads. The patient then underwent an unroofing procedure. He has remained asymptomatic without complications for two years after the second surgery.

Factors Affecting the Exercise Capacity in Pediatric Primary Hypertension

PURPOSE

Exercise training is crucial to the early intervention of pediatric primary hypertension (PHT). However, much less is known about exercise capacity in this disease. This work investigated the exercise capacity in pediatric PHT and analyzed the factors affecting exercise capacity.

METHODS

The study enrolled children with PHT at the Children's Hospital Capital Institute of Pediatrics between July 2017 and July 2020. The Bruce protocol of the treadmill exercise test (TET) was used to assess exercise capacity. Multivariate ordinal logistic regression and generalized linear models were used to analyze factors affecting exercise capacity.

RESULTS

Of 190 patients, 146 (76.8%) were male, and the median age was 13 (11, 14). Most children accomplished TET and achieved the submaximal heart rates (189 [99.5%]). Children with lower resting diastolic blood pressure (DBP) and 24 h average diastolic blood pressure (ADBP) could achieve a TET stage of 6 or more, whereas children with higher DBP and ADBP could only achieve a TET stage of 3 (P all < 0.05). Children with lower DBP and 24 h ADBP were also associated with greater metabolic equivalents (METs; r = -0.237, r = -0.179, P all < 0.05). The completion of TET stages was negatively associated with female (OR = 0.163), younger age (OR = 1.198), greater body mass index (BMI, OR = 0.921), and higher 24 h ADBP (OR = 0.952, P all < 0.05). In addition, METs were negatively associated with female (β = -1.909), younger age (β = 0.282), greater BMI (β = -0.134), and higher 24 h ADBP (β = -0.063, P all < 0.05).

CONCLUSIONS

Exercise capacity was impaired among pediatric PHT patients. Female gender, younger age, greater BMI, and higher 24 h ADBP are independently associated with the exercise capacity in pediatric PHT. These findings may help developing scientific exercise prescriptions for pediatric PHT.

Changes in clinical biochemical indexes of patients with heart failure with preserved ejection fraction or patients with hypertensive heart disease before and after treadmill exercise

BACKGROUND

The incidence of hypertension is continuously increasing. This study aimed to investigate the changes in clinical biochemical indexes of patients with heart failure with preserved ejection fraction (HFpEF), or patients with hypertensive heart disease (HHD) before and after treadmill exercise.

METHODS

Seventy-eight patients with HFpEF and 78 patients with HHD who were admitted to our hospital between February 2020 and February 2021 were selected to take a treadmill exercise test. All patients continued to exercise for 1 month. Clinical biochemical indexes [hemoglobin A1c (HbA1c), low-density lipoprotein (LDL-C), high-density lipoprotein (HDL-C), total cholesterol (TC), N-segment pro-brain natriuretic peptide (NT-proBNP), and cardiac troponin I (cTnI)] were measured before and after the treadmill exercise test and compared between the two groups. Receiver operating characteristic (ROC) curves were drawn to analyze the optimal cutoff values of the clinical biochemical indexes in the diagnosis of HFpEF. The positive diagnostic rates of the biochemical indicators for HFpEF before and after treadmill exercise were compared using the optimal cut-off value of ROC as the positive standard.

RESULTS

Before exercise, there was no significant difference in HbA1c, LDL-C, HDL-C, or TC between the two groups (P>0.05), but NT-proBNP and cTnI were significantly higher in the HFpEF group than in the HHD group (P<0.05). ROC curve analysis showed that before exercise, the best cutoff values for plasma NT-proBNP and cTnI in the diagnosis of HFpEF were 2,248.24 pg/mL and 1.14 ng/mL, respectively. After exercise, no significant difference was found in HbA1c, LDL-C, HDL-C, or TC between the two groups (P>0.05). However, the levels of NT-proBNP and cTnI in both groups were higher after exercise, with more significant increases seen in the HFPEF group (P<0.05). The positive rates of plasma NT-proBNP and cTnI in HFpEF group were statistically higher after exercise than before exercise (P<0.05).

CONCLUSIONS

The changes in plasma NT-proBNP and cTnI in patient after treadmill exercise can be used as sensitive indicators for the diagnosis and differentiation of HFpEF and HHD.

Altitude Cardiomyopathy Is Associated With Impaired Stress Electrocardiogram and Increased Circulating Inflammation Makers

Many sea-level residents suffer from acute mountain sickness (AMS) when first visiting altitudes above 4,000 m. Exercise tolerance also decreases as altitude increases. We observed exercise capacity at sea level and under a simulated hypobaric hypoxia condition (SHHC) to explore whether the response to exercise intensity represented by physiological variables could predict AMS development in young men. Eighty young men from a military academy underwent a standard treadmill exercise test (TET) and biochemical blood test at sea level, SHHC, and 4,000-m altitude, sequentially, between December 2015 and March 2016. Exercise-related variables and 12-lead electrocardiogram parameters were obtained. Exercise intensity and AMS development were investigated. After exposure to high altitude, the count of white blood cells, alkaline phosphatase and serum albumin were increased (P < 0.05). There were no significant differences in exercise time and metabolic equivalents (METs) between SHHC and high-altitude exposures (7.05 ± 1.02 vs. 7.22 ± 0.96 min, P = 0.235; 9.62 ± 1.11 vs. 9.38 ± 1.12, P = 0.126, respectively). However, these variables were relatively higher at sea level (8.03 ± 0.24 min, P < 0.01; 10.05 ± 0.31, P < 0.01, respectively). Thus, subjects displayed an equivalent exercise tolerance upon acute exposure to high altitude and to SHHC. The trends of cardiovascular hemodynamics during exercise under the three different conditions were similar. However, both systolic blood pressure and the rate-pressure product at every TET stage were higher at high altitude and under the SHHC than at sea level. After acute exposure to high altitude, 19 (23.8%) subjects developed AMS. Multivariate logistic regression analysis showed that METs under the SHHC {odds ratio (OR) 0.355 per unit increment [95% confidence intervals (CI) 0.159-0.793], P = 0.011}, diastolic blood pressure (DBP) at rest under SHHC [OR 0.893 per mmHg (95%CI 0.805-0.991), P = 0.030], and recovery DBP 3 min after exercise at sea level [OR 1.179 per mmHg (95%CI 1.043-1.333), P = 0.008] were independently associated with AMS. The predictive model had an area under the receiver operating characteristic curve of 0.886 (95%CI 0.803-0.969, P < 0.001). Thus, young men have similar exercise tolerance in acute exposure to high altitude and to SHHC. Moreover, AMS can be predicted with superior accuracy using characteristics easily obtainable with TET.

The impact of delayed heart rate recovery on prevalent hypertension

Objectives: Delayed heart rate recovery (HRR) is considered an indicator of autonomic nervous dysfunction, which is a primary pathological mechanism of hypertension. The present study aimed to explore the independent association between delayed HRR and prevalent hypertension.Methods: In this cross-sectional study, 314 inpatients were recruited between January 2018 and December 2019. HRR was defined as the peak heart rate during exercise minus the 2^nd-minute heart rate after exercise in the treadmill exercise test.Results: The mean HRR in the hypertension group was lower than that in the non-hypertension group (41 bpm vs. 46 bpm; P < 0.001). After full adjustment, each standard deviation increase in HRR was associated with a 35% decrease in the risk of prevalent hypertension (OR: 0.65, 95% CI: 0.48-0.87; P = 0.004). When the HRR was divided into quartiles, the risk in the top quartile was 26% of that in the bottom quartile (OR: 0.26, 95% CI: 0.12-0.56; P = 0.001). Furthermore, smooth curve fitting showed that the risk of prevalent hypertension decreased linearly with the increase in HRR.Conclusion: Delayed HRR was independently associated with prevalent hypertension. The association was linear and robust over the entire range of HRR. The present study suggested that delayed HRR could be used to optimize hypertension risk stratification.

[Aerobic power of students aged 13-15 years in Wuhan City]

OBJECTIVE

To measure the maximal capacity of students aged 13- 15 years by graded exercise test, and establish a model to indirect predict VO2 max.

METHODS

A total of 31 school-aged students in Wuhan participated in the study. Maximal oxygen uptake was obtained from a graded maximal exercise test, the anthropometric variables including height, weight, vital capacity( VC), resting heart rate, fat mass were measured and body mass index( BMI), body fat percentage( FAT%) was calculated. The relationships between maximal oxygen uptake and anthropometric characteristics were investigated in partial correlation analysis and a linear multiple regression model was established.

RESULTS

There was a significant difference in mass-relative VO_(2max)[( 48. 00± 5. 80) L / min vs( 39. 79 ± 6. 37) L / min, P < 0. 001], absolute VO_(2max)[( 2. 66 ± 0. 29)m L /( kg·min) vs( 2. 02 ± 0. 36) m L /( kg·min), P < 0. 001], pulse oxygen [( 13. 33 ±1. 28) m L / beat vs( 10. 34 ± 1. 70) m L / beat, P < 0. 001] between the boys and girls respectively. And a statistically significant negative correlation was observed between values of maximal oxygen uptake and weight, BMI, FAT% and resting heart rate( P <0. 05), while lean body mass was positive with VO_(2max)( P < 0. 05). Multiple regression analysis suggested that the best VO_(2max) predictive model of boys was VO_(2max)= 0. 856 +0. 044 × lean body mass- 0. 011 × resting heart rate + 0. 0002 × vital capacity( R =0. 903, R~2= 0. 816), and the prediction equation of girls was follows: VO_(2max)= 4. 769 +0. 044 × lean body mass- 0. 020 × resting heart rate- 0. 254 × age( R = 0. 813, R~2=0. 662).

CONCLUSION

The present study suggests that anthropometric characteristics might be closely related with maximal aerobic capacity and can effectively predict the maximal aerobic power.

The effect of age on right ventricular diastolic function in healthy subjects undergoing treadmill exercise test

OBJECTIVE

There is an increasing interest for the value of right ventricle (RV) in predicting exercise tolerance and prognosis in cardiovascular disease. However, there is relatively few data evaluating the effect of age on RV diastolic filling velocities during rest or exercise in healthy subjects.

METHODS

A total of 54 healthy subjects were enrolled in this study. Patients were divided into 2 groups according to their age: Group 1 (≤45-years-old) and Group 2 (>45-years-old). A treadmill exercise test was performed using modified Bruce protocol. Conventional pulsed-wave Doppler and tissue Doppler velocities were obtained both at rest and immediately after the end of exercise, respectively.

RESULTS

In the overall analysis, tricuspid flow Doppler analysis showed a significant increase in A-wave velocity, less marked rise in E-wave velocity, decreased E/A ratio and decreased E-wave deceleration time (EDT) with exercise. Tissue Doppler analysis revealed increased Aa velocity, decreased in Ea/Aa ratio and IVRT. No significant change was observed in Ea velocity and E/Ea ratio with exercise. Although diastolic velocities changed significantly with exercise, systolic velocities did not. Cardiac response to exercise differed slightly in the older subjects compared to younger ones. The older subjects were more likely to have a reduced mean rate of RV filling for the second half of diastole from baseline to peak exercise.

CONCLUSION

To distinguish normal physiological changes due to aging from those of pathologic conditions may provide benefits while evaluating patients with known or suspected cardiovascular disease.

Rehabilitation training improves exercise tolerance after percutaneous coronary intervention

The aim of this present study was to investigate the effects of training on exercise tolerance of patients with coronary heart disease after percutaneous coronary intervention. Fifty-seven cases of coronary heart disease after percutaneous coronary intervention were divided randomly into the rehabilitation training group (26 cases) and control group (31 cases). Patients in the rehabilitation training group received rehabilitation training at different stages and exercise intensities 3 d after percutaneous coronary intervention for 3 months. The heart rate, blood pressure, ECG changes in treadmill exercise test, and the frequency of anginal episodes were observed. The results showed that NST and ΣST of ECG and the frequency of anginal episodes were significantly reduced in the rehabilitation training group. In addition, exercise tolerance was improved and the total exercise time was lengthened in these patients. Moreover, ST segment depression time and emergence time of angina with exercise were also lengthened compared with controls (P < 0.05, or 0.01). However, the heart rate and blood pressure before and after exercise of the two groups were similar. The study indicated that rehabilitation training could significantly relieve angina, amend ischemic features of ECG, and improve exercise tolerance of coronary heart disease patients after percutaneous coronary intervention.

Importance of alpha 1-sympathetic activity for diurnal change in ischemic threshold in patients with stable angina

BACKGROUND

Although ischemic threshold reportedly is lower in the early morning than in the afternoon, the mechanisms that account for the diurnal change in minimal coronary vascular resistance in the potentially ischemic area are unknown.

HYPOTHESIS

We hypothesized that calcium-channel blockers and alpha 1 blockers may affect the ischemic threshold in the early morning and afternoon in patients with stable angina.

METHODS

Before and after the administration of the calcium antagonist amlodipine (5 mg) alone and combined with the alpha 1 blocker prazosin (1 mg), a treadmill exercise test using the Balke-Ware protocol was undertaken in the morning (8:00 A.M.) and repeated in the afternoon (1:00 P.M.) with 15 stable angina patients. The ischemic threshold was defined as a reciprocal of minimal coronary vascular resistance in the presence of comparable levels of myocardial ischemia indicated by 0.1 mV ST depression. Minimal coronary vascular resistance was calculated as mean blood pressure divided by coronary blood flow. Since the coronary blood flow is closely related to myocardial oxygen consumption, which can be replaced by the double product of heart rate and systolic blood pressure, minimal coronary vascular resistance was approximated to 1/heart rate.

RESULTS

At baseline, minimal coronary vascular resistance was significantly higher in the early morning than in the afternoon (8.5 +/- 0.3 x 10(-3) min/beats vs. 7.8 +/- 0.4 x 10(-3) min/beats, p < 0.01). Although treatment with amlodipine alone did not abolish the circadian pattern of minimal coronary vascular resistance (8.0 +/- 0.6 x 10(-3) min/beats vs. 7.7 +/- 0.6 x 10(-3) min/ beats, p < 0.05), the addition of prazosin virtually eliminated the diurnal difference in minimal coronary vascular resistance (7.4 +/- 0.5 x 10(-3) min/beats vs. 7.5 +/- 0.5 x 10(-3) min/beats, p = NS).

CONCLUSIONS

These findings indicate that alpha 1-sympathetic activity may play a role in the pathogenesis of the diurnal change of ischemic threshold in patients with stable angina.

Changes in serum concentration of antioxidants following treadmill exercise testing in patients with suspected ischaemic heart disease

Twenty-four subjects with suspected ischaemic heart disease underwent a treadmill exercise stress test (TEST). Nine individuals developed ischaemia as defined by standard criteria. Total plasma antioxidant status (TPAS), and serum concentrations of vitamin E were measured pre-TEST, and 0, 1, 2, 4, 8 and 24 h following the treadmill test. Mean serum vitamin E concentrations fell by 33% in the group as a whole (from 9.53 +/- 0.92 mg/L pre-TEST to 6.39 +/- 1.06 mg/L immediately post stress test, P < 0.02) and rose to baseline over the subsequent 24 h. The levels of serum vitamin E fell by 34% in the group of patients who had a positive TEST, and 32% in those who did not develop ischaemia during the TEST. Serum cholesterol concentrations also fell significantly during the TEST. In the total group serum cholesterol fell by 6.5% (P = 0.0052), and in the subgroup who were positive for ischaemia the fall in serum cholesterol was 10.3% (P = 0.004). The reduction in serum cholesterol was 4.1% in the subgroup who did not develop ischaemia (P > 0.05). Mean total plasma antioxidant status showed no significant temporal change for the group as a whole, although there was a nonsignificant decrease immediately post-TEST in the ischaemic group and a slight rise at 8 h in the group negative for ischaemia.