Abnormal heart-rate response during cardiopulmonary exercise testing identifies cardiac dysfunction in symptomatic patients with non-obstructive coronary artery disease

Obstructive Sleep Apnea as a Key Contributor to Mental Stress-Induced Myocardial Ischemia in Female Angina Patients with No Obstructive Coronary Artery Disease

Purpose

Mental stress induced myocardial ischemia (MSIMI) is regarded as the primary cause of the angina with no obstructive coronary artery disease (ANOCA). Obstructive sleep apnea (OSA) is autonomously linked to obstructive coronary heart disease, hypertension, and sudden cardiac death. Similar to the impact of psychological stress on the cardiovascular system, individuals with OSA experience periodic nocturnal hypoxia, resulting in the activation of systemic inflammation, oxidative stress, endothelial dysfunction, and sympathetic hyperactivity. The contribution of OSA to MSIMI in ANOCA patients is unclear. To explore the prevalence of OSA in ANOCA patients and the correlation between OSA and MSIMI, a prospective cohort of female ANOCA patients was recruited.

Patients and Methods

We recruited female patients aged 18 to 75 years old with ANOCA and evaluated MSIMI using positron emission tomography-computed tomography. Subsequently, Level III portable monitors was performed to compare the relationship between OSA and MSIMI.

Results

There is higher REI (7.8 vs 2.6, P=0.019), ODI (4.7 vs 9.2, P=0.028) and percentage of OSA (67.74% vs 33.33%, P=0.004) in MSIMI patients. The patients diagnosed with OSA demonstrated higher myocardial perfusion imaging scores (SSS: 1.5 vs 3, P = 0.005, SDS: 1 vs 3, P = 0.007). Adjusted covariates, the risk of developing MSIMI remained 3.6 times higher in OSA patients (β=1.226, OR = 3.408 (1.200-9.681), P = 0.021).

Conclusion

Patients with MSIMI exhibit a greater prevalence of OSA. Furthermore, the myocardial blood flow perfusion in patients with OSA is reduced during mental stress.

Abnormal heart rate responses to exercise in non-severe COPD: relationship with pulmonary vascular volume and ventilatory efficiency

BACKGROUND

Despite being a prognostic predictor, cardiac autonomic dysfunction (AD) has not been well investigated in chronic obstructive pulmonary disease (COPD). We aimed to characterise computed tomography (CT), spirometry, and cardiopulmonary exercise test (CPET) features of COPD patients with cardiac AD and the association of AD with CT-derived vascular and CPET-derived ventilatory efficiency metrics.

METHODS

This observational cohort study included stable, non-severe COPD patients. They underwent clinical evaluation, spirometry, CPET, and CT. Cardiac AD was determined based on abnormal heart rate responses to exercise, including chronotropic incompetence (CI) or delayed heart rate recovery (HRR) during CPET.

RESULTS

We included 49 patients with FEV1 of 1.2-5.0 L (51.1-129.7%), 24 (49%) had CI, and 15 (31%) had delayed HRR. According to multivariate analyses, CI was independently related to reduced vascular volume (VV; VV ≤ median; OR [95% CI], 7.26 [1.56-33.91]) and low ventilatory efficiency (nadir VE/VCO2 ≥ median; OR [95% CI], 10.67 [2.23-51.05]). Similar results were observed for delayed HRR (VV ≤ median; OR [95% CI], 11.46 [2.03-64.89], nadir VE/VCO2 ≥ median; OR [95% CI], 6.36 [1.18-34.42]).

CONCLUSIONS

Cardiac AD is associated with impaired pulmonary vascular volume and ventilatory efficiency. This suggests that lung blood perfusion abnormalities may occur in these patients. Further confirmation is required in a large population-based cohort.

Men with nonobstructive coronary disease have higher burden of ischemic heart disease detected by cardiopulmonary exercise test

BACKGROUND

Nonobstructive coronary artery disease (NOCAD), characterized by the presence of myocardial ischemic symptoms and signs without obstructive coronaries, is a common clinical condition, but it is less well understood. Few studies have analyzed the gender differences in inducible myocardial ischemia assessed by cardiopulmonary exercise test (CPET) in NOCAD.

METHODS

We conducted a study of 289 NOCAD patients (mean age 60, 56% women) with ischemic symptoms and confirmed ⫹50% coronaries stenoses by coronary angiography who underwent symptom-limited CPET. We assessed ischemic response using predicted % peak VO2 , O2 pulse trajectory, and exercise ECG test.

RESULTS

Men with NOCAD had significantly lower predicted % peak VO2 (62% vs. 73%), higher proportions of flattening pattern (16% vs. 2%), and downward patterns of O2 pulse trajectory (2% vs. 0%) (p < .0001) compared with women. In contrast, women with NOCAD had a higher prevalence of shallow patterns of O2 pulse trajectory (21% vs. 6%, p < .0001). Men with NOCAD had a higher risk ischemic profile (medium risk: 63% vs. 54%, high risk: 18% vs. 4%, p < .0001). After adjustment, men with NOCAD had significantly lower predicted % peak VO2 (β -27.4, 95% CI -30.74 to -24.07), higher risk for abnormal O2 pulse trajectories (OR 4.21, 95% CI 1.93 to 9.19), and myocardial ischemia risk per CPET parameters (OR 3.14, 95% CI 1.78 to 5.54) (p < .0001).

CONCLUSION

Men with NOCAD had a higher risk profile for ischemic heart disease per CPET. Therefore, they should receive rigorous management and follow-up to prevent cardiovascular events.

The evolving role of cardiopulmonary exercise testing in ischemic heart disease - state of the art review

PURPOSE OF REVIEW

Cardiopulmonary exercise testing (CPET) is the gold standard for directly assessing cardiorespiratory fitness (CRF) and has a relatively new and evolving role in evaluating atherosclerotic heart disease, particularly in detecting cardiac dysfunction caused by ischemic heart disease. The purpose of this review is to assess the current literature on the link between cardiovascular (CV) risk factors, cardiac dysfunction and CRF assessed by CPET.

RECENT FINDINGS

We summarize the basics of exercise physiology and the key determinants of CRF. Prognostically, several studies have been published relating directly measured CRF by CPET and outcomes allowing for more precise risk assessment. Diagnostically, this review describes in detail what is considered healthy and abnormal cardiac function assessed by CPET. New studies demonstrate that cardiac dysfunction on CPET is a common finding in asymptomatic individuals and is associated with CV risk factors and lower CRF. This review covers how key CPET parameters change as individuals transition from the asymptomatic to the symptomatic stage with progressively decreasing CRF. Finally, a supplement with case studies with long-term longitudinal data demonstrating how CPET can be used in daily clinical decision making is presented.

SUMMARY

In summary, CPET is a powerful tool to provide individualized CV risk assessment, monitor the effectiveness of therapeutic interventions, and provide meaningful feedback to help patients guide their path to improve CRF when routinely used in the outpatient setting.

Case report: A proposed role for cardiopulmonary exercise testing in detecting cardiac dysfunction in asymptomatic at-risk adolescents

Noninvasive cardiopulmonary exercise testing (CPET) provides the valuable capacity to analyze pulmonary gas exchange and cardiovascular responses that can be used to differentiate normal cardiopulmonary responses from abnormal. This case report highlights a proposed role for CPET in identifying potential cardiac pathologies in at-risk adolescents. An abnormal CPET response in an asymptomatic adolescent revealed a family history of early-age CAD. The significance of the abnormal CPET response was further supported by the presence of an elevated concentration of circulating high sensitivity C-reactive protein (hs-CRP). These findings emphasize the importance of a thorough clinical evaluation in at-risk adolescents, as CPET can aid in the early detection and management of cardiac pathologies, especially when combined with other relevant biomarkers such as plasma hs-CRP concentration, which can further suggest underlying pathology. Management considerations using serial CPET evaluations are recommended. Thus, CPET abnormalities combined with elevated hs-CRP should be taken seriously and provide justification for further evaluation and monitoring in adolescents at risk for cardiovascular disease.

Cardiopulmonary exercise testing and impedance cardiography in the assessment of exercise capacity of patients with coronary artery disease early after myocardial revascularization

Background

Patients with coronary artery disease (CAD) are characterized by different levels of physical capacity, which depends not only on the anatomical advancement of atherosclerosis, but also on the individual cardiovascular hemodynamic response to exercise. The aim of this study was evaluating the relationship between parameters of exercise capacity assessed via cardiopulmonary exercise testing (CPET) and impedance cardiography (ICG) hemodynamics in patients with CAD.

Methods

Exercise capacity was assessed in 54 patients with CAD (41 men, aged 59.5 ± 8.6 years) within 6 weeks after revascularization by means of oxygen uptake (VO2), assessed via CPET, and hemodynamic parameters [heart rate (HR), stroke volume, cardiac output (CO), left cardiac work index (LCWi)], measured by ICG. Correlations between these parameters at anaerobic threshold (AT) and at the peak of exercise as well as their changes (Δpeak–rest, Δpeak–AT) were evaluated.

Results

A large proportion of patients exhibited reduced exercise capacity, with 63% not reaching 80% of predicted peak VO2. Clinically relevant correlations were noted between the absolute peak values of VO2 versus HR, VO2 versus CO, and VO2 versus LCWi (R = 0.45, p = 0.0005; R = 0.33, p = 0.015; and R = 0.40, p = 0.003, respectively). There was no correlation between AT VO2 and hemodynamic parameters at the AT time point. Furthermore ΔVO2 (peak–AT) correlated with ΔHR (peak–AT), ΔCO (peak–AT) and ΔLCWi (peak–AT) (R = 0.52, p < 0.0001, R = 0.49, p = 0.0001; and R = 0.49, p = 0.0001, respectively). ΔVO2 (peak–rest) correlated with ΔHR (peak–rest), ΔCO (peak–rest), and ΔLCWi (peak–rest) (R = 0.47, p < 0.0001; R = 0.41, p = 0.002; and R = 0.43, p = 0.001, respectively).

Conclusion

ICG is a reliable method of assessing the cardiovascular response to exercise in patients with CAD. Some ICG parameters show definite correlations with parameters of cardiovascular capacity of proven clinical utility, such as peak VO2.

Coronary stenosis is a risk marker for impaired cardiac function on cardiopulmonary exercise test

Background

Cardiac function varies in different ways in ischemic heart disease (IHD). We aimed to evaluate the characteristics of cardiac function on cardiopulmonary exercise test (CPET) in IHD with different coronary stenoses.

Methods

Totally 614 patients with IHD were divided into non-obstructive coronary artery disease (NOCAD) (stenosis < 50%), obstructive coronary artery disease (OCAD) (stenosis 50-90%) and severe OCAD ( stenosis > 90%) according to the coronary angiography. And 101 healthy volunteers as controls. All participants performed CPET to assess cardiac function by oxygen uptake (VO₂), estimated cardiac output (CO), and heart rate (HR).

Results

Generally, the values of VO₂, CO, and HR in IHD were significantly lower than in healthy volunteers. Among 289 NOCAD, 132 OCAD, and 193 severe OCAD, significantly decreased values of VO₂, CO, HR were observed (VO₂ peak: 16.01 ± 4.11 vs. 15.66 ± 4.14 vs. 13.33 ± 3.4 mL/min/kg; CO: 6.96 ± 2.34 vs. 6.87 ± 2.37 vs. 6.05 ± 1.79 L/min; HR: 126.44 ± 20.53 vs. 115.15 ± 18.78 vs. 109.07 ± 16.23 bpm, P < 0.05). NOCAD had significantly lower VO₂ at anaerobic threshold (-1.35, 95%CI -2.16 - -0.54) and VO₂ peak (-2.05, 95%CI -3.18 - -0.93) compared with healthy volunteers after adjustment. All IHD patients were associated with low stroke volume and inefficient gas exchange (P < 0.05).

Conclusion

IHD with increasing atherosclerotic burdens were associated with impaired cardiac output and chronotropic response on CPET. NOCAD should be given more early prevention and rigorous follow-up.

Cardiopulmonary exercise testing and efficacy of percutaneous coronary intervention: a substudy of the ORBITA trial

AIMS

Oxygen-pulse morphology and gas exchange analysis measured during cardiopulmonary exercise testing (CPET) has been associated with myocardial ischaemia. The aim of this analysis was to examine the relationship between CPET parameters, myocardial ischaemia and anginal symptoms in patients with chronic coronary syndrome and to determine the ability of these parameters to predict the placebo-controlled response to percutaneous coronary intervention (PCI).

METHODS AND RESULTS

Patients with severe single-vessel coronary artery disease (CAD) were randomized 1:1 to PCI or placebo in the ORBITA trial. Subjects underwent pre-randomization treadmill CPET, dobutamine stress echocardiography (DSE) and symptom assessment. These assessments were repeated at the end of a 6-week blinded follow-up period.A total of 195 patients with CPET data were randomized (102 PCI, 93 placebo). Patients in whom an oxygen-pulse plateau was observed during CPET had higher (more ischaemic) DSE score [+0.82 segments; 95% confidence interval (CI): 0.40 to 1.25, P = 0.0068] and lower fractional flow reserve (-0.07; 95% CI: -0.12 to -0.02, P = 0.011) compared with those without. At lower (more abnormal) oxygen-pulse slopes, there was a larger improvement of the placebo-controlled effect of PCI on DSE score [oxygen-pulse plateau presence (Pinteraction = 0.026) and oxygen-pulse gradient (Pinteraction = 0.023)] and Seattle angina physical-limitation score [oxygen-pulse plateau presence (Pinteraction = 0.037)]. Impaired peak VO2, VE/VCO2 slope, peak oxygen-pulse, and oxygen uptake efficacy slope was significantly associated with higher symptom burden but did not relate to severity of ischaemia or predict response to PCI.

CONCLUSION

Although selected CPET parameters relate to severity of angina symptoms and quality of life, only an oxygen-pulse plateau detects the severity of myocardial ischaemia and predicts the placebo-controlled efficacy of PCI in patients with single-vessel CAD.

Subclinical Cardiac Dysfunction is Associated with Reduced Cardiorespiratory Fitness and Cardiometabolic Risk Factors in Firefighters

BACKGROUND

Past studies have documented the ability of cardiopulmonary exercise testing to detect cardiac dysfunction in symptomatic patients with coronary artery disease. Firefighters are at high risk for work-related cardiac events. This observational study investigated the association of subclinical cardiac dysfunction detected by cardiopulmonary exercise testing with modifiable cardiometabolic risk factors in asymptomatic firefighters.

METHODS

As part of mandatory firefighter medical evaluations, study subjects were assessed at 2 occupational health clinics serving 21 different fire departments. Mixed effects logistic regression analyses were used to estimate odds ratios (ORs) and account for clustering by fire department.

RESULTS

Of the 967 male firefighters (ages 20-60 years; 84% non-Hispanic white; 14% on cardiovascular medications), nearly two-thirds (63%) had cardiac dysfunction despite having normal predicted cardiorespiratory fitness (median peak VO₂ = 102%). In unadjusted analyses, cardiac dysfunction was significantly associated with advanced age, obesity, diastolic hypertension, high triglycerides, low high-density lipoprotein (HDL) cholesterol, and reduced cardiorespiratory fitness (all P values < .05). After adjusting for age and ethnicity, the odds of having cardiac dysfunction were approximately one-third higher among firefighters with obesity and diastolic hypertension (OR = 1.39, 95% confidence interval [CI] = 1.03-1.87 and OR = 1.36, 95% CI = 1.03-1.80) and more than 5 times higher among firefighters with reduced cardiorespiratory fitness (OR = 5.41, 95% CI = 3.29-8.90).

CONCLUSION

Subclinical cardiac dysfunction detected by cardiopulmonary exercise testing is a common finding in career firefighters and is associated with substantially reduced cardiorespiratory fitness and cardiometabolic risk factors. These individuals should be targeted for aggressive risk factor modification to increase cardiorespiratory fitness as part of an outpatient prevention strategy to improve health and safety.

Cardiopulmonary exercise test in patients with refractory angina: functional and ischemic evaluation

OBJECTIVES

Refractory angina (RA) is a chronic condition clinically characterized by low effort tolerance; therefore, physical stress testing is not usually requested for these patients. Cardiopulmonary exercise testing (CPET) is considered a gold standard examination for functional capacity evaluation, even in submaximal tests, and it has gained great prominence in detecting ischemia. The authors aimed to determine cardiorespiratory capacity by using the oxygen consumption efficiency slope (OUES) in patients with refractory angina. The authors also studied the O₂ pulse response by CPET and the association of ischemic changes with contractile modifications by exercise stress echocardiography (ESE).

METHODS

Thirty-one patients of both sexes, aged 45 to 75 years, with symptomatic (Canadian Cardiovascular Society class II to IV) angina who underwent CPET on a treadmill and exercise stress echocardiography on a lower limb cycle ergometer were studied. ClinicalTrials.gov: NCT03218891.

RESULTS

The patients had low cardiorespiratory capacity (OUES of 1.74 ± 0.4 L/min; 63.9±14.7% of predicted), and 77% of patients had a flattening or drop in O₂ pulse response. There was a direct association between Heart Rate (HR) at the onset of myocardial ischemia detected by ESE and HR at the onset of flattening or drop in oxygen pulse response detected by CPET (R = 0.48; p = 0.019).

CONCLUSION

Patients with refractory angina demonstrate low cardiorespiratory capacity. CPET shows good sensitivity for detecting abnormal cardiovascular response in these patients with a significant relationship between flattening O₂ pulse response during CEPT and contractile alterations detected by exercise stress echocardiography.

Evaluation of Critical Factors of Postoperative Arrhythmia and Preventive Measures of Deep Venous Thrombosis

The study focused on the risk factors of postoperative arrhythmia and lung infection and the preventive effects of targeted low-molecular-weight heparin (LMWH) on the occurrence of deep venous thrombosis (DVT) in patients with esophageal/cardia cancer. In this article, 82 patients who were pathologically diagnosed with esophageal/cardia cancer and underwent surgical treatment were selected as the research subjects. According to the different preoperative treatment methods, the patients were divided into the control group (without anticoagulant drugs before the operation, 44 cases) and the anticoagulation group (anticoagulant drugs were administered before the operation, 38 cases), and they were compared for basic clinical indicators and disease history. Logistic regression analysis was performed to analyze the risk factors of adverse events, and the Wells and Autar scale scores were calculated. Different groups were compared for the operation time, blood loss, and postoperative drainage volume during the operation. D-dimer was detected on the first 1, 3, 5, and 7 days after the operation, and the lower extremity venous color Doppler ultrasound was performed on the 1st and 7th days after the operation. The results showed that age ≥65 years, abnormal preoperative ECG, preoperative coronary heart disease (CHD), preoperative chronic obstructive pulmonary disease (COPD), operative time ≥4 h, and preoperative blood sodium <4.04.0 mmol/L were all risk factors for postoperative arrhythmia. Age, preoperative diabetes mellitus, preoperative COPD, length of hospital stay, and FEV1 were all risk factors for postoperative lung infections. In the control group and anticoagulation group, 11 cases (13.41%) and 5 cases (16.10%) had lower extremity DVT, respectively. The incidence of lower extremity DVT was lower in the anticoagulation group than in the control group (P < 0.01). It suggested that age, preoperative disease history, hospital stay, and operation time were risk factors for postoperative adverse events in patients with esophageal/cardia cancer. The targeted anticoagulant LMWH has a significant preventive effect on the occurrence of lower extremity DVT in patients with esophageal/cardia cancer, providing an effective reference for the prognosis and prevention of esophageal/cardia cancer.

Multiparametric exercise stress cardiovascular magnetic resonance in the diagnosis of coronary artery disease: the EMPIRE trial

BACKGROUND

Stress cardiovascular magnetic resonance (CMR) offers assessment of ventricular function, myocardial perfusion and viability in a single examination to detect coronary artery disease (CAD). We developed an in-scanner exercise stress CMR (ExCMR) protocol using supine cycle ergometer and aimed to examine the diagnostic value of a multiparametric approach in patients with suspected CAD, compared with invasive fractional flow reserve (FFR) as the reference gold standard.

METHODS

In this single-centre prospective study, patients who had symptoms of angina and at least one cardiovascular disease risk factor underwent both ExCMR and invasive angiography with FFR. Rest-based left ventricular function (ejection fraction, regional wall motion abnormalities), tissue characteristics and exercise stress-derived (perfusion defects, inducible regional wall motion abnormalities and peak exercise cardiac index percentile-rank) CMR parameters were evaluated in the study.

RESULTS

In the 60 recruited patients with intermediate CAD risk, 50% had haemodynamically significant CAD based on FFR. Of all the CMR parameters assessed, the late gadolinium enhancement, stress-inducible regional wall motion abnormalities, perfusion defects and peak exercise cardiac index percentile-rank were independently associated with FFR-positive CAD. Indeed, this multiparametric approach offered the highest incremental diagnostic value compared to a clinical risk model (χ2 for the diagnosis of FFR-positive increased from 7.6 to 55.9; P < 0.001) and excellent performance [c-statistic area under the curve 0.97 (95% CI: 0.94-1.00)] in discriminating between FFR-normal and FFR-positive patients.

CONCLUSION

The study demonstrates the clinical potential of using in-scanner multiparametric ExCMR to accurately diagnose CAD.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT03217227, Registered 11 July 2017-Retrospectively registered, https://clinicaltrials.gov/ct2/show/NCT03217227?id=NCT03217227&draw=2&rank=1&load=cart.

Cardiopulmonary exercise test in myocardial ischemia detection

Exercise electrocardiography has low sensitivity for detection of myocardial ischemia. However, when combined with cardiopulmonary exercise testing (CPEX), the sensitivity and specificity of ischemia detection improves significantly. CPEX offers unique advantages over imaging techniques in tricky situations such as balanced ischemia. Early abnormal oxygen uptake would point toward profound coronary stenosis that could be missed in perfusion imaging. CPEX could be an invaluable tool in asymptomatic left bundle branch block pattern, without exposing patients to the risks of computerized tomography or invasive coronary angiography. Normal oxygen uptake curves would rule out significant coronary stenosis as the cause of left bundle branch block pattern. Elseways, abnormal oxygen uptake in patients with normal coronary arteries could indicate microvascular angina. Furthermore, exercise capacity is an excellent predictor of cardiovascular risk in those with and without heart disease. Using two clinical cases we introduce the concept of gas-exchange and hemodynamic changes encountered in ischemic heart disease.

Effects of baseline heart rate at sea level on cardiac responses to high-altitude exposure

High-altitude (HA) exposure has been widely considered as a cardiac stress, and associated with altered cardiac function. However, the characteristics of cardiac responses to HA exposure are unclear. In total, 240 healthy men were enrolled and ascended to 4100 m by bus within 7 days. Standard echocardiography and color tissue Doppler imaging were performed at sea level and at 4100 m. In all subjects, HA exposure increased HR [65 (59, 71) vs. 72 (63, 80) beats/min, p < 0.001] but decreased the stroke volume index (SVi) [35.5 (30.5, 42.3) vs. 32.9 (27.4, 39.5) ml/m², p < 0.001], leading to an unchanged cardiac index (CI). Moreover, baseline HR was negatively correlated with HA exposure-induced changes in HR (r = - 0.410, p < 0.001) and CI (r = - 0.314, p < 0.001). Following HA exposure, subjects with lowest tertile of baseline HR showed an increased HR [56 (53, 58) vs. 65 (58, 73) beats/min, p < 0.001], left ventricular ejection fraction (LVEF) [61.7 (56.5, 68.0) vs. 66.1 (60.7, 71.5) %, p = 0.004] and mitral S' velocity [5.8 ± 1.4 vs. 6.5 ± 1.9 cm/s, p = 0.040]. However, subjects with highest tertile of baseline HR showed an unchanged HR, LVEF and mitral S' velocity, but a decreased E' velocity [9.2 ± 2.0 vs. 8.4 ± 1.8 cm/s, p = 0.003]. Our findings indicate that baseline HR at sea level could determine cardiac responses to HA exposure; these responses were characterized by enhanced LV function in subjects with a low baseline HR and by reduced LV myocardial velocity in early diastole in subjects with a high baseline HR.

Women with coronary microvascular dysfunction and no obstructive coronary artery disease have reduced exercise capacity

BACKGROUND

Both coronary microvascular dysfunction (CMD) and reduced exercise capacity are associated with adverse cardiovascular prognosis. The association between CMD and cardiopulmonary exercise testing (CPET) derived exercise capacity in symptomatic individuals without obstructive coronary artery disease (CAD) is not clear. We investigated whether exercise capacity was reduced in women with angina, CMD and no obstructive CAD compared with sex-matched controls. Furthermore, we assessed the association between CMD and other CPET-derived variables.

METHODS

All participants underwent transthoracic Doppler echocardiography of the left anterior descending artery with dipyridamole-induced vasodilation and CPET using ergometer cycle with an incremental test protocol.

RESULTS

We included 99 women with angina and no obstructive CAD (patients) and 27 asymptomatic women (controls), age (mean ± standard deviation) 61 ± 10 and 58 ± 10 years, respectively. Patients had a higher burden of risk factors compared with controls, while the weekly physical activity level was comparable between the groups (p = 0.72). CMD was present in 27 (27%) patients and 5 (19%) controls. Peak VO₂ was significantly reduced in patients with CMD compared with controls with normal coronary microvascular function ((median (IQR) 17.3 (15.5-21.3) vs. 27.3 (21.6-30.8) ml/kg/min; age-adjusted p = 0.001), independent of cardiovascular risk factors (p = 0.041). Presence of CMD in symptomatic women was also associated with diminished heart rate reserve (p < 0.001) and blunted heart rate recovery.

CONCLUSIONS

Women with angina, CMD and no obstructive CAD have markedly reduced exercise capacity compared with sex-matched controls. Moreover, combination of angina and CMD is associated with impaired heart rate response and heart rate recovery.

Chronotropic incompetence in paediatric heart transplant recipients with prior congenital heart disease

BACKGROUND

Cardiopulmonary exercise testing has been used to measure functional capacity in children who have undergone a heart transplant. Cardiopulmonary exercise testing results have not been compared between children transplanted for a primary diagnosis of CHD and those with a primary diagnosis of cardiomyopathy despite differences in outcomes. This study is aimed to compare cardiopulmonary exercise testing performance between these two groups.

METHODS

Patients who underwent heart transplant with subsequent cardiopulmonary exercise testing at least 6 months after transplant at our institution were identified. They were then divided into two groups based on primary cardiac diagnosis: CHD or cardiomyopathy. Patient characteristics, echocardiograms, cardiac catheterisations, outcomes, and cardiopulmonary exercise test results were compared between the two groups.

RESULTS

From the total of 35 patients, 15 (43%) had CHD and 20 (57%) had cardiomyopathy. Age at transplant, kidney disease, lung disease, previous rejection, coronary vasculopathy, catheterisation, and echocardiographic data were similar between the groups. Mean time from transplant to cardiopulmonary exercise testing, exercise duration, and maximum oxygen consumption were similar in both groups. There was a difference in heart rate response with CHD heart rate response of 63 beats per minute compared to cardiomyopathy group of 78 (p = 0.028). Patients with CHD had more chronotropic incompetence than those with cardiomyopathy (p = 0.036).

CONCLUSION

Primary diagnosis of CHD is associated with abnormal heart rate response and more chronotropic incompetence compared to those transplanted for cardiomyopathy.

O2 Pulse Patterns in Male Master Athletes with Normal and Abnormal Exercise Tests

PURPOSE

The clinical relevance of abnormal exercise testing (ET) results (at least 0.1 mV ST segment depression measured during exercise or recovery in three consecutive beats) in athletes without obstructive coronary artery disease (CAD) is not well understood. It is unknown whether this phenomenon reflects a physiological adaptation to sport or a truly ischemic response and a concomitant attenuated stroke volume (SV) response. The aim of this study was to investigate if athletes with abnormal ET results without obstructive CAD showed signs of an attenuated SV response using cardiopulmonary ET parameters.

METHODS

A total of 78 male master athletes with abnormal ET results without obstructive CAD underwent cardiopulmonary ET. ΔO2 pulse/Δwork rate (WR), ΔV˙O2/ΔWR, and Δheart rate (HR)/ΔWR were assessed and compared with data from 78 male master athletes with normal ET results, matched for age, sports characteristics, and exercise capacity.

RESULTS

The ΔO2 pulse/ΔWR ratio beyond anaerobic threshold in athletes with abnormal ET results was lower than that in athletes with normal ET results (0.73 ± 0.41 vs 1.12 ± 0.54, respectively, P < 0.001). The ΔV˙O2/ΔWR ratio was also lower in athletes with abnormal ET results (0.9 ± 0.2 vs 1.0 ± 0.3, respectively, P = 0.041). Furthermore, these athletes showed a greater increase in HR in the last 2 min of exercise (ΔHR/ΔWR ratio: 1.19 ± 0.5 vs 0.80 ± 0.6, P < 0.001).

CONCLUSION

Athletes with abnormal ET results without obstructive CAD showed an attenuated O2 pulse slope, decreased ΔV˙O2/ΔWR ratio, and increased ΔHR/ΔWR ratio beyond anaerobic threshold when compared with athletes with a normal ET result. These results support the hypothesis that at least a part of the athletes with an abnormal ET in absence of obstructive CAD have an attenuated SV response at high-intensity exercise.

A practical clinical approach to utilize cardiopulmonary exercise testing in the evaluation and management of coronary artery disease: a primer for cardiologists

PURPOSE OF REVIEW

There is growing clinical interest for the use of cardiopulmonary exercise testing (CPET) to evaluate patients with or suspected coronary artery disease (CAD). With mounting evidence, this concise review with relevant teaching cases helps to illustrate how to integrate CPET data into real world patient care.

RECENT FINDINGS

CPET provides a novel and purely physiological basis to identify cardiac dysfunction in symptomatic patients with both obstructive-CAD and nonobstructive-CAD (NO-CAD). In many cases, abnormal cardiac response on CPET may be the only objective evidence of potentially undertreated ischemic heart disease. When symptomatic patients have NO-CAD on coronary angiogram, they are still at increased risk for cardiovascular events. This problem appears to be more common in women than men and may warrant more aggressive risk factor modification. As the main intervention is lifestyle (diet, smoking cessation, exercise) and medical therapy (statins, angiotensin-converting enzyme inhibitors, beta-blockers), serial CPET testing enables close surveillance of cardiovascular function and is responsive to clinical status.

SUMMARY

CPET can enhance outpatient evaluation and management of CAD. Diagnostically, it can help to identify physiologically significant obstructive-CAD and NO-CAD in patients with normal routine cardiac testing. CPET may be of particular value in symptomatic women with NO-CAD. Prognostically, precise quantification of improvements in exercise capacity may help to improve long-term lifestyle and medication adherence for this chronic condition.

Cardiopulmonary Exercise Testing: What Is its Value?

Compared with traditional exercise tests, cardiopulmonary exercise testing (CPET) provides a thorough assessment of exercise integrative physiology involving the pulmonary, cardiovascular, muscular, and cellular oxidative systems. Due to the prognostic ability of key variables, CPET applications in cardiology have grown impressively to include all forms of exercise intolerance, with a predominant focus on heart failure with reduced or with preserved ejection fraction. As impaired cardiac output and peripheral oxygen diffusion are the main determinants of the abnormal functional response in cardiac patients, invasive CPET has gained new popularity, especially for diagnosing early heart failure with preserved ejection fraction and exercise-induced pulmonary hypertension. The most impactful advance has recently come from the introduction of CPET combined with echocardiography or CPET imaging, which provides basic information regarding cardiac and valve morphology and function. This review highlights modern CPET use as a single or combined test that allows the pathophysiological bases of exercise limitation to be translated, quite easily, into clinical practice.