Exercise impedance cardiography reveals impaired hemodynamic responses to exercise in hypertensives with dyspnea

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.

Cardiac function and exercise capacity in patients with metabolic syndrome: A cross-sectional study

Background

Metabolic syndrome is a pre-diabetes condition that is associated with increased cardiovascular morbidity and mortality. We aimed to explore how exercise capacity, cardiac structure, and function were affected in patients with metabolic syndrome.

Methods

Outpatients with echocardiography and exercise stress test combined with impedance cardiography (ETT + ICGG) results available from Nov 2018 to Oct 2020 were retrospectively enrolled. Echocardiographic, ETT + ICG profiles, and exercise performance were compared between patients with metabolic syndrome and the ones without. Sensitivity analyses were performed excluding patients without established coronary heart disease and further 1:1 paired for age and gender, respectively. Multiple linear regression was used to find out related predictors for maximal metabolic equivalents (METs).

Results

Three hundred and twenty-third patients were included, among whom 97 were diagnosed as metabolic syndrome. Compared to patients without metabolic syndrome, echocardiography showed that patients with metabolic syndrome had a significantly lower E/A ratio (p &lt; 0.001). Besides, they have larger left atrium, larger right ventricle, and thicker interventricular septum (all p &lt; 0.001), but similar left ventricular ejection fraction (P = 0.443). ICG showed that patients with metabolic syndrome had significantly higher stroke volume at rest and maximum (p &lt; 0.001), higher left cardiac work index at rest and maximum (p = 0.005), higher systemic vascular resistance (SVR) at rest (p &lt; 0.001), but similar SVI (p = 0.888). During exercise, patients with metabolic syndrome had lower maximal METs (p &lt; 0.001), and a higher proportion suffering from ST-segment depression during exercise (p = 0.009). Sensitivity analyses yielded similar results. As for the linear regression model, 6 independent variables (systolic blood pressure, BMI, E/A ratio, the height of O wave, the peak value of LCWi, and the baseline of SVR) had statistically significant effects on the maximal METs tested in exercise (R = 0.525, R2 = 0.246, P &lt; 0.001).

Conclusion

Patients with metabolic syndrome had significant structural alteration, apparent overburden of left ventricular work index, pre-and afterload, which may be the main cause of impaired exercise tolerance.

RELATIONSHIP BETWEEN THE ECHOCARDIOGRAPHIC RESPONSE OF DIASTOLIC FUNCTION AND LOAD EXERCISE

ABSTRACT Introduction: This article studies the echocardiographic images of patients and observes the changes in diastolic cardiac function after exercise. Objective: This article tries to find the relationship between cardiac images during exercise and the diagnosis of myocardial ischemia. Methods: Samples of people with equal fitness for the same exercise area were selected with specific equipment to measure the sample ventricular strain curve before and after 5 minutes to exercise with a load. The diastolic strain index (SDI) ratio before and after exercise assesses the relationship between myocardial ischemia and exercise load. Results: The test results showed no significant difference in the range of motion of the cardiac atrioventricular annulus both before and after subjects were subjected to intense exertion exercise. A significant change in slope was noted in the ECG data curve about the exercise index, in addition to a reduction in the diastolic period. Conclusion: When the exercise load increases, it can easily cause changes in the ventricular wall. This can make local myocardial dysfunction more prone. Level of evidence II; Therapeutic studies - investigation of treatment results.

Limited usefulness of resting hemodynamic assessments in predicting exercise capacity in hypertensive patients

Reliable assessments of reduced exercise capacity based on resting tests are one of the major challenges in clinical practice. The aim of this study was to evaluate the relationship between hemodynamic parameters obtained via resting tests (echocardiography and impedance cardiography (ICG)) and objective parameters of exercise capacity assessed via cardiopulmonary exercise testing and exercise ICG in patients with controlled arterial hypertension (AH). The left ventricular ejection fraction (LVEF), global longitudinal strain (GLS), diastolic function parameters (e', E/A, E/e'), cardiac output (CO), stroke volume (SV), and systemic vascular resistance index were evaluated for any correlations with selected parameters of exercise capacity, such as peak oxygen uptake (VO₂) and peak CO in 93 people with AH (mean age 54 years, 47 women). Statistically relevant correlations occurred between indices of exercise capacity (peak VO₂; peak CO) and only the following hemodynamic parameters: diastolic blood pressure (R = 0.23, p = 0.026; R = 0.24, p = 0.021; respectively), e' (R = 0.32, p = 0.002; R = 0.24, p = 0.027), E/e' (R = 0.35, p < 0.001; ns), E/A (R = 0.23, p = 0.030; R = 0.21, p = 0.047), SV at rest (ns; R = 0.24, p = 0.019), and CO at rest (ns; R = 0.21, borderline p = 0.052). No significant correlations between the exercise capacity parameters and either LVEF or GLS were observed. No hemodynamic parameter proved to be an independent correlate of either peak VO₂ or peak CO. The association between hemodynamic parameters at rest and parameters of exercise capacity was weak and limited to selected parameters of diastolic function. Exercise capacity assessment in patients with AH based on resting tests alone is insufficiently reliable and should be supplemented with exercise tests.

The non-invasive evaluation of heart function in patients with an acute myocardial infarction: The role of impedance cardiography

BACKGROUND

The purpose of this study was to analyze hemodynamic changes in patients treated with percutaneous coronary intervention (PCI) at an early stage of acute myocardial infarction (AMI) and at 1-month follow-up.

METHODS

Patients with AMI (n = 27) who underwent PCI were analyzed using impedance cardiography (ICG). ICG data were collected continuously (beat by beat) during the whole PCI procedure and thereafter at every 60 s for the next 24 h. Blood pressure was taken every 10 min and stored for analysis. Additionally the following parameters were measured: cardiac index (CI), stroke volume index (SVi), left cardiac work index (LCWi), contractility index (CTi), ventricular ejection time (VET), systemic vascular resistance index (SVRi), thoracic fluid content index (TFCi) and heart rate (HR).

RESULTS

In the first 24 h after PCI all the contractility parameters including CI, SVi, LCWi, CTi and VET significantly decreased, whereas HR, SVRi and TFCi increased compared to baseline. All of the parameters examined got normalized at 1 month. The CI, SVi, LCWi, CTi, SVRi did not significantly differ from baseline, however the HR and VET were significantly lower compared to first day after PCI CONCLUSIONS: Cardiac performance deteriorates early after PCI and normalizes after 1 month in patients with an AMI. ICG is useful for hemodynamic monitoring of AMI patients during and after invasive therapy.