High-frequency QRS analysis improves the specificity of exercise ECG testing in women referred for angiography

Revisiting the diagnostic and prognostic significance of high-frequency QRS analysis in cardiovascular diseases: a comprehensive review

Cardiovascular diseases (CVDs) present a significant global public health threat, contributing to a substantial number of cases involving morbidity and mortality. Therefore, the early and accurate detection of CVDs plays an indispensable role in enhancing patient outcomes. Decades of extensive research on electrocardiography at high frequencies have yielded a wealth of knowledge regarding alterations in the QRS complex during myocardial ischemia, as well as the methodologies to assess and quantify these changes. In recent years, the analysis of high-frequency QRS (HF-QRS) components has emerged as a promising non-invasive approach for diagnosing various cardiovascular conditions. Alterations in HF-QRS amplitude and morphology have demonstrated remarkable sensitivity as diagnostic indicators for myocardial ischemia, often surpassing measures of ST-T segment changes. This comprehensive review aims to provide an intricate overview of the current advancements, challenges, and prospects associated with HF-QRS analysis in the field of CVDs.

The combination of high-frequency QRS and ST-segment alterations during exercise stress tests enhanced the diagnostic efficacy for coronary artery disease

BACKGROUND

High-frequency QRS (HF-QRS) manifests as a novel adjunct electrocardiographic marker with potential utility in coronary artery disease (CAD) detection.

HYPOTHESIS

We hypothesize that HF-QRS analysis may be superior to conventional ST-segment analysis in detecting CAD, and the combination of these two analyses in the exercise stress test may enhance the diagnostic efficacy for CAD.

METHODS

The study incorporated a sample of 157 patients (mean age 62 ± $\pm $  9 years) referred for nonemergent angiography. Before angiography, patients underwent exercise stress testing utilizing an upright bicycle. High-resolution electrocardiogram (ECG) data were collected during the exercise test, facilitating both HF-QRS and conventional ST-segment analyses. The diagnostic efficacy of HF-QRS and ST-segment analysis were compared, utilizing angiographic outcomes as the gold standard. The study design integrated HF-QRS analysis and ST-segment analysis via sequential and concurrent testing protocols.

RESULTS

In terms of CAD detection, HF-QRS analysis displayed superior sensitivity compared to conventional ST-segment analysis (63% vs. 37%, p = .002). The serial test significantly increased specificity from 79% to 97% (p = .002) compared to ST-deviation analysis alone. It showed a markedly low sensitivity of 26%. The parallel test significantly increased sensitivity from 37% to 77% (p < .001), while retaining a moderate level of specificity of 51%. The quantity of ECG leads exhibiting a positive HF-QRS response demonstrated a correlation with the severity of CAD (p < .001).

CONCLUSIONS

HF-QRS analysis exhibited superior sensitivity in detecting angiographically confirmed CAD relative to conventional ST-segment analysis. Moreover, the combination of HF-QRS and ST-segment alterations during exercise stress test enhanced the diagnostic efficacy for CAD.

Comparative analysis of ischemic changes in electrocardiogram and coronary angiography results: A retrospective study

To improve the correct diagnosis rate of coronary heart disease and to explore the guiding value of electrocardiogram (ECG) ST-T ischemic changes in the clinical diagnosis of coronary heart disease.A retrospective analysis was conducted on a total of 310 cases who underwent a conventional 12-lead ECG, 12-lead dynamic ECG (DECG, Holter) with ST-T ischemic changes, and then coronary angiography (CA) within 1 week in Qingdao Sttarr Heart Hospital from June 2015 to April 2020 in the study. Ischemic ST-T changes were evaluated using conventional diagnostic criteria, and Judkins diagnostic criteria were used in CA. The sensitivity and specificity of ECG were analyzed.The specificity of ST-T changes in conventional ECG for the diagnosis of coronary heart disease is 33.7% and the sensitivity is 66.0%. The specificity of ST-T changes in Holter in the diagnosis of coronary heart disease is 55.6% and the sensitivity is 32.2%. The sensitivity of conventional ECG for the diagnosis of coronary heart disease is better than Holter, but its specificity is inferior to Holter. The negative likelihood ratios of the 2 ECGs for the diagnosis of coronary heart disease were 1.0 and 1.22, both >0.1, and the positive likelihood ratios were 0.99 and 0.73, both <10. The positive results of ST-T in conventional ECG were 128 males (65.7%), 77 females (66.9%), (P < .05), 148 cases (74.7%) in the group ≥60 years old, and 75 cases in the group less than 60 years (67%), (P > .05). The positive results of ST-T change of DECG were 135 males (69.2%), 69 females (60.0%), (P < .05), 152 cases (78.7%) in the group ≥60 years, and 83 cases (70.9%) in the group less than 60 years, (P > .05). Coronary heart disease-related factors: symptoms, hypertension, diabetes, cancer, family history, smoking history as independent variables, and a binary multivariate logistic regression analysis was performed.The sensitivity of DECG in the diagnosis of myocardial ischemia in women and the elderly was slightly higher than that in men and young cases. ST-T ischemic changes in ECG are more significant for the diagnosis of coronary heart disease in male patients. Smoking, hypertension, diabetes, and family history are all high-risk factors for coronary heart disease.

Changes in High-Frequency Intracardiac Electrogram Indicate Cardiac Ischemia

High-frequency QRS (HFQRS) analysis of surface ECG is a reliable marker of cardiac ischemia (CI). This study aimed to assess the response of HFQRS signals from standard intracardiac electrodes (iHFQRS) to CI in swine and compare them with conventional ST-segment deviations. Devices with three intracardiac leads were implanted in three swine in a controlled environment. CI was induced by inflating a balloon in epicardial coronary arteries. A designated signal-processing algorithm was applied to quantify the iHFQRS content before, during, and after each occlusion. iHFQRS time responses were compared to conventional ST-segment deviations. Thirty-three over thirty-nine (85%) of the occlusions presented significant reduction in the iHFQRS signal, preceding ST-segment change, being the only indicator of CI in brief occlusions. iHFQRS was found to be an early indicator for the onset of CI and demonstrated superior sensitivity to conventional ST-segment deviations during brief ischemic episodes.

Results of bicycle exercise stress test in patients with stable coronary heart disease depending on the angiographic signs of atherosclerotic lesions of coronary arteries

The aim. To identify features of exercise response in coronary heart disease (CHD) patients depending on coronary artery condition and to identify factors associated with a positive test in patients with no obstructive coronary artery disease (INOCA). Materials and methods. The study included 105 patients diagnosed with stable coronary artery disease (CAD) who were hospitalized at the City Clinical Hospital No. 8 of the Kharkiv City Council. The criteria for diagnosis of ischemia with no obstructive coronary artery disease (INOCA) were met by 53 patients who formed group I. Group II included 52 patients who were consistently hospitalized in the period from June to December 2020, and had obstructive CAD for more than 50 % according to their coronary angiography (CAG). Results. According to the results of bicycle exercise stress test, a positive test was significantly more often registered in group II – n=30 (57.7 %) patients compared to group I – n=19 (35.8 %) patients (p=0.0249). The duration of the test in patients of group I was significantly longer than 420 seconds [290–540], compared with group II – 300.0 [210.0–540.0] (р=0.0352). Also, in patients in group II, the maximum volume of the test performed was probably lower than in group I (p=0.0324). When calculating the double product, it was also found that in group I its value was significantly higher compared to group II (p=0.0292). In group I there was a significantly higher rate of chronotropic reserve (44.0 [26.0–60.0]), compared with group II (p=0.0168). Elevated total cholesterol (above 5 mmol/l) is a statistically significant and independent factor of a positive exercise test in patients with INOCA (OR, 1.98 [0.9992-3.926], p=0.05). A correlation was found between the level of exercise tolerance and smoking in INOCA-patients (r =-0.388975, p=0.010899). Patients who underwent MINOCA also showed reduced tolerance to exercise (r=-0.3104, p=0.042721) Conclusions. The sensitivity of bicycle exercise stress test in patients with CAD depends on the presence and severity of atherosclerotic lesions of the coronary arteries (63 % in stenotic atherosclerosis, 36 % in no obstructive coronary arteries. It was found that exercise test duration, double product, chronotropic and inotropic reserve of the heart in patients with a positive exercise test with INOCA were significantly higher compared with patients with obstructive CAD. Independent factors associated with a positive exercise test in patients with no obstructive CAD are an increase in total cholesterol (multivariate regression logistic analysis).

An innovative method based on Shannon energy envelope and summit navigation for detecting R peaks of noise stress test signals

In recent decades, there has been an increased demand for the processing of electrocardiogram (ECG) signals because of its significant role in diagnosing cardiac diseases. The QRS complex is the dominant feature of the ECG signal. The detection of QRS complexes is thus an essential part of almost any ECG signal processing systems. This paper presents a developed QRS complex detection method using dominant peak extraction and Shannon energy envelope for useful ECG signal analysis. The algorithm is divided into three main stages: pre-processing, searching for dominant peaks, and removing false R peaks. The proposed algorithm is validated in static ECG recordings from the MIT-BIH Arrhythmia Database (MITDB) and noise-contaminated ECG stress tests from the Glasgow University Database (GUDB), separately. The method compares favorably with conventional and recently published results of many QRS detection algorithms on the same MITDB. Subsequently, valuable performance coefficients are also found on the GUDB. The average detection accuracy of finding R peaks exceed 99% on both the databases, especially for cardiac stress test records with high interference levels. The method enables a highly effective ECG signal processing tool under various noises, artifacts, abnormalities, and morphologies.

Incremental value of high-frequency QRS analysis for diagnosis and prognosis in suspected exercise-induced myocardial ischaemia

Aim:

Exercise stress testing is used to detect myocardial ischaemia, but is limited by low sensitivity and specificity. The authors investigated the value of the analysis of high-frequency QRS components as a marker of abnormal depolarization in addition to standard ST-deviations as a marker of abnormal repolarization to improve the diagnostic accuracy.

Methods and results:

Consecutive patients undergoing bicycle exercise stress nuclear myocardial perfusion imaging were prospectively enrolled. Presence of myocardial ischaemia, the primary diagnostic endpoint, was adjudicated using MPI and coronary angiography. Automated high-frequency QRS analysis was performed in a blinded fashion. The prognostic endpoint was major adverse cardiac events (MACEs) during two years of follow-up. Exercise-induced ischaemia was detected in 147/662 patients (22%). The sensitivity of high-frequency QRS was similar to ST-deviations (46% vs. 43%, p=0.59), while the specificity was lower (75% vs. 87%, p&lt;0.001). The combined use of high-frequency QRS and ST-deviations classified 59% of patients as ‘rule-out’ (both negative), 9% as ‘rule-in’ (both positive) and 32% in an intermediate zone (one test positive). The sensitivity for ‘rule-out’ and the specificity for ‘rule-in’ improved to 63% and 97% compared with ST-deviation analysis alone (both p&lt;0.001). MACE-free survival was 90%, 80% and 42% in patients in the ‘rule-out’, intermediate and ‘rule-in’ groups (p&lt;0.001). After adjustment for age, gender, ST-deviations and clinical post-test probability of ischaemia, high-frequency QRS remained an independent predictor for the occurrence of MACEs.

Conclusion:

The use of high-frequency QRS analysis in addition to ST-deviation analysis improves the diagnostic accuracy during exercise stress testing and adds independent prognostic information.

High-frequency QRS analysis to supplement ST evaluation in exercise stress electrocardiography: Incremental diagnostic accuracy and net reclassification

BACKGROUND

Exercise stress electrocardiography (ECG) alone is underutilized in part due to poor diagnostic accuracy. High-frequency QRS analysis (HF-QRS) is a novel tool to supplement ST evaluation during stress ECG. We compared the diagnostic accuracy and net reclassification of HF-QRS analysis compared with ST evaluation for substantial myocardial ischemia by exercise SPECT myocardial perfusion imaging (MPI).

METHODS AND RESULTS

Exercise SPECT MPI was performed in 257 consecutive eligible patients (mean age 59 ± 12, 67% male). An ischemic HF-QRS pattern was defined as a ≥ 1 µV absolute reduction and a ≥ 50% relative reduction of the root-mean-square of the 150-250 Hz band signal in ≥ 3 leads. Left ventricular ischemia of ≥ 10% on SPECT MPI was the diagnostic standard for substantial myocardial ischemia. HF-QRS analysis demonstrated incremental diagnostic value to ST evaluation plus clinical risk factors (AUC 0.804 vs 0.749, P < .0001). A HF-QRS + ST -analysis strategy identified 92.3% of subjects with substantial ischemia and no abnormality in 59.9% of the cohort. No cardiac events occurred in patients without substantial ischemia identified by HF-QRS analysis.

CONCLUSIONS

In this prospective analysis, exercise stress ECG with HF-QRS analysis identified any and substantial ischemia with high diagnostic accuracy and may allow more than half of referred patients to safely avoid imaging.

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Zusammenfassung. Das Belastungs-EKG ist zur Erfassung einer Myokardischämie und der Leistungsfähigkeit das am weitesten verbreitete Standardverfahren in Klinik und Praxis der Kardiologie und zählt nach wie vor zu den wichtigsten Funktionsuntersuchungen des Herz-Kreislauf-Systems. Ein Belastungs-EKG sollte symptomlimitiert durchgeführt werden und ca. 10 min dauern, damit eine hohe Leistung mit möglichst hohem Doppelprodukt und damit eine möglichst hohe Aussagekraft des Tests bezüglich Ischämie und Prognose erreicht wird. Sollarbeitskapazität und Herzfrequenz sind als Abbruchkriterien nicht geeignet. Verbesserte Interpretationsmöglichkeiten durch Einbeziehung neuer Variablen (Hyper-Q) können die Diagnosegenauigkeit bei Patienten mit mittlerer Vortestwahrscheinlichkeit erhöhen. Trotz hochentwickelter bildgebender Verfahren mit grösserer Sensitivität und Spezifität bleibt ein korrekt durchgeführtes Belastungs-EKG aufgrund der ubiquitären Verfügbarkeit und des guten Kosten-Nutzen-Verhältnisses ein fester Bestandteil der Basisdiagnostik.

Diagnostic accuracy of treadmill exercise tests among Chinese women with coronary artery diseases: A systematic review and meta-analysis

BACKGROUND

The treadmill exercise test (TET) is one of the most common noninvasive diagnosis approaches for ischemic heart diseases, but potential reduction of TET accuracy among Chinese female patients was ignored by most studies, especially in perimenopause women. Hence, we aim to perform a systematic review and meta-analysis evaluating the TET diagnostic accuracy for Chinese women compared with coronary angiography (CAG).

METHODS

PubMed, MEDLINE, EMBASE, CNKI and WANFANG (1990 to 2015) were performed to identify studies assessing the diagnostic accuracy of TET versus CAG. Random effects modeling strategies were used to produce summary receiver operating characteristic (SROC) curves, including overall estimates for sensitivity and specificity.

RESULTS

A total of 19 studies involving 2396 Chinese females were included in our systematic review. TET has moderate levels of sensitivity (0.80) and specificity (0.65) to detect coronary artery stenoses in female patients with suspected coronary artery diseases, generating 0.79 of the area under the curve (AUC). In subgroup analyses, the pooled sensitivity of postmenopause and premenopausal/perimenopausal groups were 0.83 and 0.80, respectively. However, the postmenopause group has a higher pooled specificity: 0.68 versus 0.32 compared with premenopausal/perimenopausal women, and a higher corresponding AUC (0.81 versus 0.56).

CONCLUSIONS

TET may be used as a triage test for women with suspected and subclinical CAD. The positive results of TET should be treated with caution because of its higher false-positive, especially for premenopausal/perimenopausal women, and further confirmatory diagnosis is needed. However, patients with negative TET results could be precluded for further evaluation using CAG, and avoid unnecessary risk and economic burden to patients.

Women-specific factors to consider in risk, diagnosis and treatment of cardiovascular disease

In the era of individualized medicine, gaps in knowledge remain about sex-specific risk factors, diagnostic and treatment options that might reduce mortality from cardiovascular disease (CVD) and improve outcomes for both women and men. In this review, contributions of biological mechanisms involving the sex chromosomes and the sex hormones on the cardiovascular system will be discussed in relationship to the female-specific risk factors for CVD: hypertensive disorders of pregnancy, menopause and use of hormonal therapies for contraception and menopausal symptoms. Additionally, sex-specific factors to consider in the differential diagnosis and treatment of four prevalent CVDs (hypertension, stroke, coronary artery disease and congestive heart failure) will be reviewed with emphasis on areas where additional research is needed.

Fragmented QRS Is Associated with Improved Predictive Value of Exercise Treadmill Testing in Patients with Intermediate Pretest Likelihood of Significant Coronary Artery Disease

BACKGROUND

The predictive value of exercise treadmill testing (ETT) remains inadequate in diagnosing patients with suspected coronary artery disease (CAD) and needs to be improved.

OBJECTIVE

The aim of this study was to investigate whether the presence of FQRS on 12-lead ECG would increase the PPV of ETT in patients with an intermediate likelihood of CAD.

METHODS

fQRS, defined as the presence of notched R or S waves without accompanying typical bundle branch block or the existence of an additional wave-like RSR' pattern in the original QRS complex (with a duration of <120 ms), was assessed in 95 patients with positive ETT. Coronary angiogram (CA) was performed in all patients, divided into two groups as the significant CAD group and nonsignificant CAD group according to coronary artery lesions. The differences between the groups in terms of the presence of fQRS and clinical characteristics were investigated.

RESULTS

The mean age of patients was 51.3 ± 11.3 years, and 74 of them were males (77.9%). FQRS was present in 47 (49.5%) patients, and significant CAD was demonstrated in 51 subjects (53.7%) among the enrolled subjects. fQRS was more prevalent in the significant CAD group compared to nonsignificant CAD group (P < 0.001). The presence of FQRS increased the PPV of positive ETT from 53.7% to 85.1%. In addition, FQRS was associated with the increased risk of significant CAD in multivariate analysis (OR = 2.839, P < 0.001).

CONCLUSION

In clinical practice, the presence of fQRS in patients with positive ETT may support clinicians during the decision-making process with regard to the referral for a coronary angiography.