Definitions and incidence of cardiac syndrome X: review and analysis of clinical data

Coronary microvascular dysfunction, arrythmias, and sudden cardiac death: A literature review

The coronary vascular system has a unique structure and function that is adaptive to myocardial demand. It is composed of a continuous network of vessels receding in size from epicardial arteries to the microvascular circulation. Failure to meet myocardial demand results in ischemia, angina, and adverse myocardial outcomes. It is evident that 50 % of patients with angina have a non-obstructive coronary disease and 66 % of these patients have coronary microvascular dysfunction (CMD). The impact of CMD on the atria and ventricles is exhibited through its association with atrial fibrillation and distortion of ventricular repolarization. Ultimately, this influence increases the risk of mortality, morbidity, and sudden cardiac arrest. CMD serves as an independent risk for atrial fibrillation, increases ventricular electrical inhomogeneity, and contributes to the progression of cardiac disease. The underlying pathogenesis may be attributed to oxidative stress evident through reactive oxygen species, impaired vasoactive function, and structural disorders such as fibrotic changes. Myocardial ischemia, brought about by a demand-supply mismatch in CMD, may create a milieu for ventricular arrythmia and sudden cardiac arrest through distortion of ventricular repolarization parameters such as QT dispersion and corrected QT dispersion.

Predictive value of the systemic immune inflammatory index in cardiac syndrome x

İNTRODUCTION: Patients with normal coronary arteries in whom increased vasospasm cannot be detected with the stress test should be evaluated in terms of cardiac syndrome x (CSX). İnflammatory systems are effective in endothelial activation and dysfunction in CSX. The systemic immune inflammation index (SII) is thought to be an important factor in determining the course of diseases, especially in infectious diseases or other diseases, as an indicator of the inflammation process. The aim of this study is to determine the role of SII levels in the diagnosis of CSX disease.

METHODS

The study group included 80 patients who applied to the cardiology department of Fırat University with typical anginal complaints between October 2021 and April 2022, and were diagnosed with ischemia after the myocardial perfusion scan, and then coronary angiography was performed and normal coronary arteries were observed.

RESULTS

When the study and control groups were examined according to age, gender and body mass index, hypertension, smoking, diabetes mellitus, dyslipidemia and family history, no statistical significant difference was observed between the groups. It was observed that there was a significant difference between the high sensitive C- reactive protin levels of the individuals in the study and control groups (p = 0.028). SII levels measured in samples taken from patients were significantly higher than control subjects (p = 0.003). SII cutoff at admission was 582 with 82% sensitivity and 84% specificity (area under the curve 0.972; 95% CI:0.95-0.98;p < 0.001).

CONCLUSION

It has been demonstrated that systemic SII parameters, which can be simply calculated with the data obtained from the complete blood count and do not require additional costs, can contribute to the prediction of CSX disease.

Psychological factors of suspect coronary microvascular dysfunction in patients undergoing SPECT imaging

BACKGROUND

Patients with myocardial ischemia in the absence of obstructive coronary artery disease (CAD) often experience anginal complaints and are at risk of cardiac events. Stress-related psychological factors and acute negative emotions might play a role in these patients with suspect coronary microvascular dysfunction (CMD).

METHODS AND RESULTS

295 Patients (66.9 ± 8.7 years, 46% women) undergoing myocardial perfusion single-photon-emission computed tomography (MPI-SPECT), were divided as follows: (1) a non-ischemic reference group (n = 136); (2) patients without inducible ischemia, but with a history of CAD (n = 62); (3) ischemia and documented CAD (n = 52); and (4) ischemia and suspect CMD (n = 45). These four groups were compared with regard to psychological factors and acute emotions. Results revealed no differences between the groups in psychological factors (all P > .646, all effect sizes d < .015). State sadness was higher for patients with suspect CMD (16%) versus the other groups (P = .029). The groups did not differ in the association of psychological factors or emotions with anginal complaints (all P values > .448).

CONCLUSION

Suspect CMD was not associated with more negative psychological factors compared to other groups. State sadness was significantly higher for patients with suspect CMD, whereas no differences in state anxiety and other psychological factors were found.

Definitions and Epidemiology of Coronary Functional Abnormalities

Coronary functional abnormalities are frequent causes of angina pectoris, particularly in patients with unobstructed coronary arteries. There is a spectrum of endotypes of functional coronary abnormalities with different mechanisms of pathology including enhanced vasoconstriction (i.e. coronary artery spasm) or impaired vasodilatation, such as impaired coronary flow reserve or increased microvascular resistance. These vasomotor abnormalities can affect various compartments of the coronary circulation such as the epicardial conduit arteries and/or the coronary microcirculation. Unequivocal categorisation and nomenclature of the broad spectrum of disease endotypes is crucial both in clinical practice as well as in clinical trials. This article describes the definitions of coronary functional abnormalities with currently accepted cut-off values, as well as diagnostic methods to identify and distinguish endotypes. The authors also provide a summary of contemporary data on the prevalence of the different endotypes of coronary functional abnormalities and their coexistence.

Helicobacter pylori infection and susceptibility to cardiac syndrome X: A systematic review and meta-analysis

BACKGROUND

Cardiac syndrome X (CSX) is characterized by persistent angina with normal coronary arteries. Several pathophysiologic mechanisms have been introduced, particularly Helicobacter pylori (H. pylori) infection.

AIM

To investigate the association between H. pylori infection and CSX.

METHODS

All studies related to H. pylori infection and CSX were evaluated by comprehensive searches of global databases such as ISI Web of Knowledge, PubMed, Scopus, EMBASE, and Google scholar. Statistical analyses of selected articles were evaluated based on the summary odds ratio (OR). Finally, heterogeneity and publication bias were estimated using the I² statistic and Cochrane Q-test as well as Begg’s and Egger’s tests.

RESULTS

A total of 11 studies met our inclusion criteria and 1435 patients (63% female, and 37% male) were reviewed. A significant association was observed between female patients and this syndrome (P = 0.02). Our results showed a positive association between infection with this pathogen and presence of CSX (OR: 5.65; 95% confidence interval [CI]: 4.17-7.64; I²: 82.20). However, no significant association was observed with cagA-positive H. pylori strains and this syndrome (OR: 0.97; 0.56-1.70 with 95%CI). Given the heterogeneity and publication bias, the results need to confirmed by further prospective investigation.

CONCLUSION

Based on our results, H. pylori infection is associated with an increased risk of CSX. This bacterium appears to play a major role in the pathogenesis of CXS by inducing persistent inflammation.

Subjects with microvascular angina have longer GT repeats polymorphism in the haem oxygenase-1 gene promoter

Objective: Few studies have investigated haem oxygenase-1 gene (HMOX1) promoter polymorphism in microvascular angina (MVA).Materials and methods: HMOX1 promoter (GT)_n repeats were examined in healthy controls (N = 220) and MVA subjects (N = 181).Results: The distribution of genotype of SS, SL and LL were significantly different in MVA (17%, 51%, 33%) vs. normal controls (35%, 46%, 20%) (p < 0.001, S allele: ≤30 repeats, L allele: >30 repeats). In multivariate analysis, carrier of L allele (odds ratio 2.772, p < 0.001) was a significant predictor for the diagnosis of MVA.Conclusions: Subjects with MVA had longer HMOX1 promoter (GT)_n repeats than the healthy controls. Trial registration number: NCT01198730 at https://clinicaltrials.gov.

Receptor for advanced glycation end products gene polymorphisms in cardiac syndrome X

Endothelial and microvascular dysfunction serve important roles in the formation and pathogenesis of cardiac syndrome X (CSX). Expression of receptor for advanced glycation end products (RAGE) is suggested to be increased in several conditions, including diabetes, inflammation and vascular diseases. In the present study, RAGE gene polymorphisms in patients with CSX and healthy controls were investigated. A total of 114 patients, diagnosed with CSX using coronary angiography results following complaints of angina and objective ischemia, and 103 healthy controls participated in the study. Whether there was a difference in genotype distributions of RAGE gene -374T/A, -429T/C and Glys82Ser polymorphisms between patients with CSX and healthy controls was investigated. Following DNA isolation from blood samples of the participants, the polymorphic regions were examined by quantitative polymerase chain reaction, and the genotyping results were statistically analyzed. When the genotypic distributions of -374T/A, -429T/C and Gly82Ser polymorphisms were investigated in patients with CSX and healthy controls, no statistically significant differences were identified between the two groups (P>0.05). Likewise, no statistically significant differences were observed in the allelic distributions of all 3 polymorphic regions (P>0.05). To the best of our knowledge, the present study also investigated the association between CSX and RAGE gene polymorphisms for the first time. No statistically significant differences in RAGE gene polymorphisms between the CSX and control groups were observed. We hypothesized that significant results may be obtained by increasing the numbers of patients and healthy controls in future studies.

Chest Pain Characteristics in Cardiac Syndrome X Compared to Coronary Artery Disease

AIM

This study aimed to assess if clinical remarks gained by analysis of the present and past medical history of patients undergoing elective coronary angiography (ECA) due to typical chest pain can help to predict the outcome of ECA.

MATERIAL AND METHODS

One hundred and fifty-four ECA candidates with a history of typical chest were seen on the same day intended for ECA in the cardiac centre of AlShaab Teaching Hospital, Khartoum, Sudan. The details of the present complaints, characteristics of chest pain, past medical and socioeconomic history were recorded from each subject guided by a questionnaire. ECA confirmed CAD in 112 of the studied patients and were considered as the test group. The remaining patients (N = 42) were diagnosed as CSX after exclusion of significant narrowing of the coronary vessels and were considered as the control group.

RESULTS

Univariate analysis of pain characteristics among patients undergoing coronary angiography revealed that pain is less likely to radiate to the neck (OR = 0.44, 95% CI = 0.21 - 0.91, P = 0.027) and the back (OR = 0.48, 95% CI = 0.23 - 1.00, P = 0.049) in patients with CAD. Presence of shortness of breathing and/or dizziness significantly decrease the odds of having abnormal coronary angiography (OR = 0.30 and 0.48, 95% CI = 0.12 - 0.77 and 0.22 - 0.92, P = 0.013 and 0.030 respectively). Past history of diabetes mellitus significantly increases the odds of having abnormal coronary angiography (OR = 3.96, 95% CI = 1.68 - 9.30, P = 0.002). In contrast, past medical history of migraine decreases the odds of having positive finding in ECA (OR = 0.31, 95% CI = 0.13 - 0.72, P = 0.006).

CONCLUSION

Characteristics of chest pain are comparable in CAD and CSX. However, pain is less likely to radiate to the neck and/or the back in the first group. Presence of dyspnea and dizziness during angina attacks as well as the history of migraine significantly decreases the odds of having abnormal coronary angiography.

Retinal microvascular changes in microvascular angina: Findings from the Australian Heart Eye Study

OBJECTIVE

Microvascular changes in microvascular angina are poorly understood due to difficulties in imaging the coronary microcirculation in vivo. The retinal microvasculature may reflect changes in coronary microcirculation. We assessed microvascular changes in the retina in patients with microvascular angina and compared them with patients with angiographically proven coronary artery disease.

METHODS

We performed retinal photography and coronary angiography on 915 patients. Retinal vessel calibers were measured using a validated computer-assisted method; coronary artery disease was graded from coronary angiograms. Microvascular angina was defined as angina with <25% stenosis in all coronary epicardial arteries.

RESULTS

A total of 139 patients (15.2%) had microvascular angina, while 776 (84.8%) had coronary artery disease. Participants with microvascular angina and coronary artery disease had similar retinal arteriolar and venular calibers. After adjustment for age, ethnicity, mean arterial pressure, diabetes, current smoking, body mass index, and fellow vessel caliber, women with smaller venules were threefold more likely to have microvascular angina than women with larger venules (multivariable-adjusted odds ratio 3.54, 95% confidence interval 1.35 to 9.24, P < 0.01). This difference was not observed in men.

CONCLUSIONS

Microvascular angina in women was associated with microvascular changes distinct from those in coronary artery disease.

Discrimination between Obstructive Coronary Artery Disease and Cardiac Syndrome X in Women with Typical Angina and Positive Exercise Test; Utility of Cardiovascular Risk Calculators

Introduction: Nearly 40% of women with typical angina and a positive exercise tolerance test (ETT) have normal or near normal coronary angiography (CAG) labeled as cardiac syndrome X (CSX). Objective: We performed this study to evaluate the power of common cardiovascular risk calculators to distinguish patients with CSX from those with coronary artery disease (CAD). Methods: 559 women participated in the study. Three risk scores, including (1) newly pooled cohort equation of American College of Cardiology/American Heart Association (ACC/AHA) to predict 10 years risk of first atherosclerotic cardiovascular hard event (ASCVD), (2) Framingham risk score (FRS) for the prediction of 10 years coronary heart disease, and (3) the SCORE tool to estimate 10-year risk of cardiovascular mortality (SCORE), were applied. Results: CAD was diagnosed in 51.5% of the patients. 11.6% of the population had ASCVD < 2.5%, and only 13.8% of these patients had CAD on their CAG. By choosing FRS, 14.4% of patients had FRS < 7.5%, and only 11.3% of these patients had recorded CAD on CAG, while the rest of the patients were diagnosed as CSX. Using the SCORE model, 13.8% of patients had the least value (<0.5%) in whom the prevalence of CAD was 19.9%. The area under receiver operating characteristic curve (AUROC) to discriminate CSX from CAD was calculated for each scoring system, being 0.750 for ASCVD, 0.745 for FRS, and 0.728 for SCORE (p value for all AUROCs < 0.001). The Hosmer⁻Lemeshow chi squares (df, p value) for calibration were 8.787 (8, 0.361), 11.125 (8, 0.195), and 10.618 (8, 0.224) for ASCVD, FRS, and SCORE, respectively. Conclusions: Patients who have ASCVD < 2.5% or FRS < 7.5% may be appropriate cases for noninvasive imaging (Such as coronary CT angiography). CAG is indicated for patients with ASCVD ≥ 7.5% and FRS ≥ 15%, whereas the patients with intermediate risk need comprehensive patient⁻physician shared decision-making.

The presence of late potentials after percutaneous coronary intervention for the treatment of acute coronary syndrome as a predictor for future significant cardiac events resulting in re-hospitalization

INTRODUCTION

We previously reported that LP positive patients after percutaneous coronary intervention (PCI) had higher rate of re-hospitalization in the small-scale study (135 patients). In this study, we evaluated correlation between LP and later cardiac events leading to re-hospitalization more extensively in greater population.

METHODS AND RESULTS

A 24-h high-resolution (HR) ambulatory electrocardiogram (ECG) was performed in 421 patients that received PCI for the treatment of acute coronary syndrome (ACS) within 30 days. Various baseline characteristics and post-PCI ECG parameters including LP were examined for correlation with later re-hospitalization. LP was evaluated based on 3 different conditions, i.e., the worst, mean and best values, from 24-h signal-averaged QRS wave data. During the post-PCI follow-up period (611 ± 489.0 days), 90 patients were re-hospitalized due to cardiac events. Multivariate analysis identified only positive LP based on the worst value as an independent predictor for re-hospitalization with OR 2.26. Most of re-hospitalization cases (>75%) were predominantly attributed to ischemic events. LP positive population had significantly higher incidences of ischemic events as well as overall re-hospitalization compared to LP negative population. The predictive power of LP was decreased when it was combined with other variables. The receiver operating characteristic analysis determined the LP cut-off values consistent with the LP positive criteria previously reported and standardized.

CONCLUSION

The presence of LP in the 24-h HR ambulatory ECG post-PCI was an independent predictor for a risk of re-hospitalization due to ischemic cardiac events in ACS patients.

NONOBSTRUCTIVE CORONARY ARTERY DISEASE - CLINICAL RELEVANCE, DIAGNOSIS, MANAGEMENT AND PROPOSAL OF NEW PATHOPHYSIOLOGICAL CLASSIFICATION

SUMMARY – New data gathered from large clinical trials indicate that nonobstructive coronary artery disease (non-CAD) is a clinical entity that should not be ignored. It is estimated that 50% of female population undergoing coronarography are diagnosed with non-CAD. There is also an increase in the prevalence of non-CAD in both genders, which is probably due to gradual expanding of clinical indications for angiography in patients with angina. Furthermore, considering the increased mortality risk established recently, a prognosis of non-CAD is not benign as previously thought. However, the concept and definition of non-CAD remains elusive causing difficulties in diagnosis and treatment. One of the major shortcomings is the exclusion-based diagnosis of non-CAD. Furthermore, treatment of non-CAD still presents a great challenge and optimal therapy is yet to be determined. There are two major hypotheses explaining the pathophysiological mechanisms of non-CAD, i.e. ischemic hypothesis based on abnormal microvascular dysfunction and non-ischemic one based on altered pain perception. This review encompasses a broader spectrum of pathophysiological mechanisms of non-CAD, and proposes a new way of classification based on the major disorder involved: type I (ischemic mechanisms) and type II (non-ischemic mechanisms), depending on which mechanism predominates. Hopefully, this would provide new insights in the understanding of this disorder, thus leading to accurate and early diagnosis and successful treatment, especially considering the increased mortality risk in these patients.

Treatment of Angina: Where Are We?

Ischaemic heart disease is a major cause of death and disability worldwide, while angina represents its most common symptom. It is estimated that approximately 9 million patients in the USA suffer from angina and its treatment is challenging, thus the strategy to improve the management of chronic stable angina is a priority. Angina might be the result of different pathologies, ranging from the “classical” obstruction of a large coronary artery to alteration of the microcirculation or coronary artery spasm. Current clinical guidelines recommend antianginal therapy to control symptoms, before considering coronary artery revascularization. In the current guidelines, drugs are classified as being first-choice (beta-blockers, calcium channel blockers, and short-acting nitrates) or second-choice (ivabradine, nicorandil, ranolazine, trimetazidine) treatment, with the recommendation to reserve second-line modifications for patients who have contraindications to first-choice agents, do not tolerate them, or remain symptomatic. However, such a categorical approach is currently questioned. In addition, current guidelines provide few suggestions to guide the choice of drugs more suitable according to the underlying pathology or the patient comorbidities. Several other questions have recently emerged, such as: is there evidence-based data between first- and second-line treatments in terms of prognosis or symptom relief? Actually, it seems that newer antianginal drugs, which are classified as second choice, have more evidence-based clinical data that are more contemporary to support their use than what is available for the first-choice drugs. It follows that actual guidelines are based more on tradition than on evidence and there is a need for new algorithms that are more individualized to patients, their comorbidities, and pathophysiological mechanism of chronic stable angina.

Hemorheological dysfunction in cardiac syndrome X

BACKGROUND

Cardiac syndrome X (CSX) is often described as angina or angina-like chest pain with a normal coronary arteriogram, yet the underlying pathophysiological mechanisms have not been fully elucidated. The aim of the current study was to determine alterations in blood rheology (erythrocyte aggregation and deformability, plasma viscosity - PV) in patients with CSX.

METHODS

The study comprised 26 CSX patients (55.77 ± 12.33 years) and 37 age- and sex-matched (56.32 ± 11.98 years) healthy controls. Erythrocyte aggregation and deformability were measured by an ektacytometer and PV with a rotational viscometer.

RESULTS

Erythrocyte deformability measured at 1.69 and 3.00 Pa was lower in the CSX patients compared to the controls (p = .0001 and .017, respectively). Erythrocyte aggregation index (AI) (72.758 ± 7.65 vs. 66.483 ± 6.63, p = .002) and PV measured at a shear rate of 375 s^-1 (1.932 ± 0.225 vs. 1.725 ± 0.331, p = .019) were significantly higher in patients with CSX. When AI, RDW and erythrocyte deformability measured at 1.69 Pa were evaluated together, it was observed that the increase in AI and RDW augments the risk of having CSX (OR: 1.2 and 2.65, respectively), while the rise in deformability decreases this risk (OR = 0.02).

CONCLUSIONS

Hemorheological impairments are associated with CSX.

Novel Scoring System for Prediction of Cardiac Syndrome X in Women with Typical Angina and a Positive Exercise Tolerance Test

A major diagnostic challenge for cardiologists is to distinguish cardiac syndrome X (CSX) from obstructive coronary artery disease in women with typical angina and a positive exercise tolerance test (ETT). We performed this study to develop a scoring system that more accurately predicts CSX in this patient population. Data on 976 women with typical angina and a positive ETT who underwent coronary angiography at our center were randomly divided into derivation and validation datasets. We developed a backward stepwise logistic regression model that predicted the presence of CSX, and a scoring system was derived from it. The derivation dataset (809 patients) was calibrated by uing a Hosmer-Lemeshow goodness-of-fit test (8 degrees of freedom; χ²=12.9; P=0.115), and the area under the curve was 0.758. The validation dataset (167 patients) was calibrated in the same way (8 degrees of freedom; χ²=9.0; P=0.339), and the area under the curve was 0.782. Independent predictors of CSX were age <55 years; negative histories of smoking, diabetes mellitus, hyperlipidemia, hypertension, or familial premature coronary artery disease; and highly positive ETTs. A total score >9.5 was the optimal cutoff point for differentiating CSX from obstructive coronary artery disease. Our proposed scoring system is a simple, objective, and accurate system for distinguishing CSX from obstructive coronary artery disease in women with typical angina and positive ETTs. It may help determine which of these patients need invasive coronary angiograms or noninvasive tests like computed tomographic coronary angiography.

Galectin-3: One Molecule for an Alphabet of Diseases, from A to Z

Galectin-3 (Gal-3) regulates basic cellular functions such as cell-cell and cell-matrix interactions, growth, proliferation, differentiation, and inflammation. It is not surprising, therefore, that this protein is involved in the pathogenesis of many relevant human diseases, including cancer, fibrosis, chronic inflammation and scarring affecting many different tissues. The papers published in the literature have progressively increased in number during the last decades, testifying the great interest given to this protein by numerous researchers involved in many different clinical contexts. Considering the crucial role exerted by Gal-3 in many different clinical conditions, Gal-3 is emerging as a new diagnostic, prognostic biomarker and as a new promising therapeutic target. The current review aims to extensively examine the studies published so far on the role of Gal-3 in all the clinical conditions and diseases, listed in alphabetical order, where it was analyzed.

The prognostic value of asymmetric dimethylarginine in patients with cardiac syndrome X

Background

The pathophysiology of cardiac syndrome X is multifactorial and endothelial dysfunction has been implicated as important contributing factor. Asymmetric dimethylarginine (ADMA), characterized as a circulating endogenous inhibitor of nitric oxide synthase, may have been implicated as an important contributing factor for the development of endothelial dysfunction. In this study, we aim to assess the predictive power of ADMA for long-term prognosis in patients with cardiac syndrome X.

Methods and results

We enrolled 239 consecutive patients with cardiac syndrome X diagnosed by coronary angiography. The mean age was 58.7±10.1 years. The patients were grouped into tertiles according to the plasma ADMA levels: <0.38 μmol/l (tertile I), 0.38–0.44 μmol/l (tertile II), and >0.44 μmol/l (tertile III). All patients were followed up for a mean period of 6.5±1.5 years (median: 6.3 years, inter-quartile range: 5.7–8.0 years). During the follow-up period, major adverse events (MAE) were observed in 15 patients (6.3%), including 13 deaths. The plasma ADMA levels in patients who developed MAE were significantly higher than those who did not (0.48±0.06 μmol/l vs. 0.42±0.08 μmol/l, p = 0.005). In multivariate Cox regression analysis adjusted for age, eGFR and LVEF, ADMA tertile I and II were identify to be associated with a significantly lower risk of MAE compared to ADMA tertile III (p = 0.017). By considering the plasma ADMA level as a continuous variable, the plasma ADMA level remained a significant independent predictor for outcomes of MAE, and the relative risk of MACE increased by 50% when plasma ADMA level increased by 1 SD of value (p = 0.018).

Conclusions

In patients with cardiac syndrome X, elevated plasma ADMA levels appeared to be an independent predictor of long-term adverse clinical outcomes.

International standardization of diagnostic criteria for microvascular angina

Standardization of diagnostic criteria for ischemic symptoms due to coronary microvascular dysfunction (CMD) is needed for further investigation of patients presenting with anginal chest pain consistent with "microvascular angina" (MVA). At the annual Coronary Vasomotion Disorders International Study Group (COVADIS) Summits held in August 2014 and 2015, the following criteria were agreed upon for the investigative diagnosis of microvascular angina: (1) presence of symptoms suggestive of myocardial ischemia; (2) objective documentation of myocardial ischemia, as assessed by currently available techniques; (3) absence of obstructive CAD (<50% coronary diameter reduction and/or fractional flow reserve (FFR) >0.80) (4) confirmation of a reduced coronary blood flow reserve and/or inducible microvascular spasm. These standardized criteria provide an investigative structure for mechanistic, diagnostic, prognostic and clinical trial studies aimed at developing an evidence base needed for guidelines in this growing patient population. Standardized criteria will facilitate microvascular angina registries and recruitment of suitable patients into clinical trials. Mechanistic research will also benefit from the implementation of standardized diagnostic criteria for MVA.

Differential expression of circulating vascular cell adhesion molecule-1 in subjects with coronary artery disease and cardiac syndrome X without known diabetes mellitus

CONTEXT

Inflammation is one of the mechanisms underlying cardiac syndrome X (CSX).

OBJECTIVES

Few studies have compared the expression of inflammatory or adhesion molecules between coronary artery disease (CAD) versus CSX.

MATERIALS AND METHODS

Ninety-two CSX and 145 CAD subjects without known diabetes mellitus underwent coronary angiogram for angina.

RESULTS

Vascular cell adhesion molecule (VCAM)-1 (median, 507 versus 431 ng/ml, p = 0.001) was significantly higher in the CAD group. In the binary regression, VCAM-1 was a significant differential factor for CAD versus CSX.

DISCUSSION AND CONCLUSION

Adhesion molecules might be implicated in the differential expression of macro versus microvascular coronary disease.

TRIAL REGISTRATION NUMBER

NCT01198730 at https://clinicaltrials.gov.

Ventricular late potential in cardiac syndrome X compared to coronary artery disease

BACKGROUND

Although ventricular late potential (VLP) was extensively studied in risk stratification of myocardial infarction (MI) patients, comparable researches evaluating presence of VLP in MI-free coronary artery disease (CAD) and cardiac syndrome X (CSX) subjects are scarce. This study aimed to compare presence of VLP between CSX and CAD patients.

METHODS

Signal average ECG (SAECG) was performed to 49 patients with a history of typical cardiac pain before undergoing diagnostic coronary angiography (DCA) in Al-Shaab cardiac center, Khartoum, Sudan. QRS duration, duration of the terminal part of the QRS complex with amplitude less than 40 microvolts (LAS40) and the root mean square voltage of the terminal 40 milliseconds (RMS40) of the filtered QRS complex were identified for each patient. Presence of two or more of QRS duration > 120 ms, RMS40 > 38 ms and LAS40 < 20 μV was considered indicative of VLP. Associations between VLP and patients grouped according to DCA results were assessed using appropriate statistical tests.

RESULTS

VLP was present in 11.11% (3.63%-24.66%) and 15.38% (2.66%-42.23%) of patients with CAD and CSX respectively. Presence of VLP was comparable in patients with CAD and CSX (OR = 0.69, 95% CI = 0.11-6.05, P = 0.692), even after controlling for the possible variations in gender, age, body mass index (BMI), hypertension and diabetes mellitus in the studied groups.

CONCLUSION

Presence of VLP is comparable among CSX and CAD patients.

Anxiety Level and Cardiac Autonomic Modulations in Coronary Artery Disease and Cardiac Syndrome X Patients

BACKGROUND

Anxiety and cardiac autonomic modulations (CAM) were thoroughly investigated in coronary artery disease (CAD) and cardiac syndrome X (CSX) patients worldwide, but not among Sudanese with similar pathology.

AIMS

To compare levels of anxiety and CAM between Sudanese patients with CSX and CAD.

MATERIALS AND METHODS

Anxiety was evaluated in 51 CAD and 26 CSX patients using Taylor Manifest anxiety score (TMAS) questionnaire while heart rate variability derived indices were used to assess CAM, namely natural logarithm of low frequency (LnLF), high frequency (LnHF) and LF/HF ratio (LnLF/HF).

RESULTS

Low anxiety levels were achieved by 6 (23.1%) and 9 (17.6%) patients with CSX and CAD respectively. High anxiety level was achieved by only one (3.8%) patient, who was suffering from CSX. TMAS was significantly higher in CSX (31.27 (21.97)) compared to CAD (21.86 (12.97), P = 0.021). However, abnormally increased anxiety was not associated with higher risk of CSX. LnLF, LnHF and LnLF/HF were comparable in CAD and CSX patients.

CONCLUSION

CSX and CAD patients showed comparable CAM. Although anxiety levels were higher in CSX compared to CAD, TMAS ≥ 35 failed to show significant association with CSX.

Post-challenge insulin concentration is useful for differentiating between coronary artery disease and cardiac syndrome X in subjects without known diabetes mellitus

BACKGROUND

Cardiac syndrome X (CSX) is characterized by angina pectoris but with patent coronary arteries. Our previous study demonstrated that subjects with CSX had a higher fasting insulin-resistance (IR) than the controls. However, few studies have investigated the degree of IR, including oral glucose tolerance test (OGTT)-derived indices and profiles of metabolic abnormalities between CSX and coronary artery disease (CAD).

METHODS

Ninety-two CSX and 145 CAD subjects without known diabetes mellitus (DM) underwent coronary angiogram (CAG) for angina pectoris and also agreed to receive OGTT and glycated hemoglobin (HbA_1C) evaluations for screening abnormal glucose regulation and IR.

RESULTS

CAD group had more subjects with metabolically unhealthy obesity (52.4 vs. 31.5%, p < 0.001) than the CSX group. The CAD group had higher OGTT 2 h glucose and insulin (both p < 0.005) while fasting glucose, insulin and HOMA-IR were similar to those of CSX subjects. In the binary regression analysis, OGTT 2 h insulin and being metabolic unhealthy were significantly different between the CAD and CSX groups, but there were no significant differences in Matsuda index, fasting glucose, insulin, HOMA-IR, or HbA_1C.

CONCLUSIONS

Post challenge OGTT 2 h insulin and being metabolic unhealthy were useful parameters in differentiating between CAD and CSX in subjects without known DM but suffered from angina pectoris and underwent CAG. Different degrees of IR and metabolic abnormalities might be implicated in the pathogenesis of micro vs. macro vascular coronary diseases. Trial registration NCT01198730 at https://clinicaltrials.gov, Registered Sep. 8, 2010.

QT Interval Derived Measurements in Patients with Cardiac Syndrome X Compared to Coronary Artery Disease

Previous studies assessing effect of ischemia on ventricular repolarization are mostly directed toward patients with coronary artery disease (CAD); however, similar reports on cardiac syndrome X (CSX) are scarce. Whether microvascular dysfunction of CSX and ischemia induced by CAD produce comparable effect on ventricular repolarization is unclear and deserve further studies. In the present study, ECG measures of ventricular repolarization were compared between CAD and CSX patients (40 subjects in each group). Following evaluation of sociodemographic characteristics, medical and past medical history, a resting ECG was used to assess measurements of ventricular repolarization in each patient, namely, QT interval (QT), corrected QT interval (QTc), QT dispersion (QTd), corrected QT dispersion (QTcd), adjacent QT dispersion (AdQTd), QT dispersion ratio (QTdR), JT dispersion (JTd), and Corrected JT dispersion (JTcd). Results showed comparable QT intervals and QTd in CAD and CSX patients even after adjustment for the possible variations in gender, age and body mass index of the studied groups. Although JTd was increased in CSX subjects (26.6 ± 7.2 ms) compared with CAD patients (22.7 ± 6.5 ms, p = 0.019), statistical significance disappeared after correcting JT for variations in heart rate. QT and QTc were significantly below 440 ms in CAD as well as CSX patients (p < 0.001). In contrast, maximum QTd, maximum QTcd and AdQTd of CAD and CSX patients were significantly above 440 ms (p < 0.001). The means of JTd and JTcd were significantly above 22 ms and 24 ms respectively (p < 0.001, p = 0.001) in CSX but not CAD patients (p = 0.529, p = 0.281). The present findings clearly demonstrate comparable measures of ventricular repolarization in CAD and CSX patients and consequently an equal risk of cardiac events in both groups.

Diagnostic accuracy of resting left ventricular akinesia/hypokinesia in predicting abnormal coronary angiography

Background

Although several reports demonstrate the efficacy of stress echocardiography in diagnosing coronary artery disease, comparable studies on the competence of the same imaging technique at rest are limited. This study aimed to evaluate whether ventricular akinesia/hypokinesia and left ventricular ejection fraction (LVEF) < 55 % at rest are useful in predicting abnormal coronary angiography.

Methods

This study prospectively enrolled 100 diagnostic coronary catheterization candidates. Any routine echocardiography that the candidates had undergone before diagnostic coronary catheterization was reviewed. Patients were subclassified according to the presence and location of ventricular akinesia/hypokinesia, LVEF, and the results of diagnostic coronary catheterization. LVEF < 55 % was considered below the normal physiological limit. Abnormal coronary angiography was defined as narrowing of half or more of the caliber of at least one major coronary artery.

Results

Abnormal coronary angiography was significantly associated with akinesia/hypokinesia (OR = 4.85, P = 0.002) and LVEF < 55 % (OR = 5.75, P = 0.001). Screening of akinesia/hypokinesia and LVEF < 55 % as diagnostic tools for abnormal coronary angiography achieved comparable sensitivities (87.2 % vs. 88.9 %), specificities (41.5 vs. 41.8), and diagnostic accuracies (41.5 vs. 41.8). Left ventricular anterior wall akinesia/hypokinesia achieved a higher diagnostic odds ratio (9.7), sensitivity (95 %), and negative predictive value (96.4 %) compared with other types of akinesia/hypokinesia.

Conclusion

The overall diagnostic accuracy of akinesia/hypokinesia and LVEF < 55 % to predict abnormal coronary angiography was poor, probably owing to significant influences of macro- as well as micro-vascular ischemia on left ventricular function.

Coronary microvascular dysfunction, microvascular angina, and treatment strategies

Angina without coronary artery disease (CAD) has substantial morbidity and is present in 10% to 30% of patients undergoing angiography. Coronary microvascular dysfunction (CMD) is present in 50% to 65% of these patients. The optimal treatment of this cohort is undefined. We performed a systematic review to evaluate treatment strategies for objectively-defined CMD in the absence of CAD. We included studies assessing therapy in human subjects with angina and coronary flow reserve or myocardial perfusion reserve <2.5 by positron emission tomography, cardiac magnetic resonance imaging, dilution methods, or intracoronary Doppler in the absence of coronary artery stenosis ≥50% or structural heart disease. Only 8 papers met the strict inclusion criteria. The papers were heterogeneous, using different treatments, endpoints, and definitions of CMD. The small sample sizes severely limit the power of these studies, with an average of 11 patients per analysis. Studies evaluating sildenafil, quinapril, estrogen, and transcutaneous electrical nerve stimulation application demonstrated benefits in their respective endpoints. No benefit was found with L-arginine, doxazosin, pravastatin, and diltiazem. Our systematic review highlights that there is little data to support therapies for CMD. We assess the data meeting rigorous inclusion criteria and review the related but excluded published data. We additionally describe the next steps needed to address this research gap, including a standardized definition of CMD, routine assessment of CMD in studies of chest pain without obstructive CAD, and specific therapy assessment in the population with confirmed CMD.

Different definition of microvascular angina

We sometimes encounter patients with microvascular angina (MVA), a disease characterized by anginal pain without abnormal coronary arteriographic findings or coronary spasm. More than 40 years have passed since MVA was first confirmed. The terms 'syndrome X', 'cardiac syndrome X' and 'microvascular dysfunction' have also been used to describe conditions similar to MVA, but all with slightly different definitions. The cause of MVA seems almost certain to be organic and functional abnormalities of the small arteries of the heart. Patients with MVA are likely to suffer from endothelial dysfunction and other microvascular abnormalities of both the coronary and peripheral arteries. The major treatment of MVA has been medication, most often calcium channel blockers. The prognosis of MVA is generally excellent, although symptoms remain in many studies. Some MVA patients with accompanying hypertensive heart disease have gone on to develop progressive left ventricular dysfunction, with poor prognosis. The different definitions applied to the terms used to describe this condition, what we refer to here as MVA, can confound issues involved in diagnosis, prognosis and proper treatment. Therefore, it is extremely important to distinguish primary MVA without underlying heart disease from secondary MVA to explore the disease mechanism and examine the clinical characteristics. It is more than 40 years since Likoff first confirmed this disease; therefore, all researchers know that strict diagnostic criteria for MVA should be immediately established.

Emergence of Nonobstructive Coronary Artery Disease: A Woman's Problem and Need for Change in Definition on Angiography

Recognition of ischemic heart disease (IHD) is often delayed or deferred in women. Thus, many at risk for adverse outcomes are not provided specific diagnostic, preventive, and/or treatment strategies. This lack of recognition is related to sex-specific IHD pathophysiology that differs from traditional models using data from men with flow-limiting coronary artery disease (CAD) obstructions. Symptomatic women are less likely to have obstructive CAD than men with similar symptoms, and tend to have coronary microvascular dysfunction, plaque erosion, and thrombus formation. Emerging data document that more extensive, nonobstructive CAD involvement, hypertension, and diabetes are associated with major adverse events similar to those with obstructive CAD. A central emerging paradigm is the concept of nonobstructive CAD as a cause of IHD and related adverse outcomes among women. This position paper summarizes currently available knowledge and gaps in that knowledge, and recommends management options that could be useful until additional evidence emerges.

Value of Chromosome 9p21 Polymorphism for Prediction of Cardiovascular Mortality in Han Chinese Without Coronary Lesions: An Observational Study

Variants at chromosome 9p21 are associated with coronary artery disease (CAD). However, the longitudinal effects of 9p21 variants on cardiovascular mortality remain controversial and may depend on whether the patient has CAD. We tested the hypothesis that the single-nucleotide polymorphism (SNP) rs4977574 is associated longitudinally with cardiovascular death in patients without detectable coronary lesions. We enrolled patients who underwent coronary angiography for angina pectoris but had normal angiographic findings. Laboratory analyses and rs4977574 TaqMan genotyping were performed using fasting blood samples collected during hospitalization. Cardiovascular and all-cause mortality rates were acquired from a national database. Among the 679 enrolled subjects with neither myocardial infarction nor an angiographic coronary lesion, 28 (19.0%) of the 147 homozygous GG carriers suffered a cardiovascular death, compared with 63 (11.8%) of the 532 subjects with the AG or AA genotype during the median 12.3 years (interquartile range 8.6-12.7 years) of follow-up. In a recessive model, cardiovascular mortality was significantly higher in subjects with the GG genotype than in those with the other genotypes (hazard ratio, 1.69, 95% confidence interval 1.08 to 2.64; P = 0.021). In this follow-up study, rs4977574, a tag SNP at chromosome 9p21, was shown to be associated with cardiovascular mortality in Taiwanese patients with angina pectoris but no coronary lesions.

Zinc and copper levels are not correlated with angiographically-defined coronary artery disease in sudanese patients

We investigated zinc and copper levels in angiographically defined obstructive coronary artery disease (CAD) in patients undergoing elective coronary angiography in El-Shaab Hospital, Sudan. We performed a cross-sectional study. One hundred forty-two patients were enrolled. Sociodemographic and medical characteristics were collected using a questionnaire. Glucose, lipid, zinc, and copper levels were measured. Out of 142 patients, 102 (71.8%) had CAD and 40 (28.2%) had patent coronary arteries. There were no significant differences in median (interquartile range) zinc [118.5 (97.2-151.0) vs. 130.0 (106.0-174.0) μg/ml, P = 0.120] and copper [150.6 (125.0-183.0) vs. 158 (132.0-180.0) μg/mL, P = 0.478] levels between patients with CAD and those with patent coronary arteries. In linear regression analysis, there were no associations between CAD and zinc and copper levels. The current study failed to show any significant association between CAD and zinc and copper levels.

Cardiac syndrome X: Clinical characteristics revisited

BACKGROUND

Cardiac syndrome X includes a heterogenous group of patients with angina but normal epicardial coronaries in angiography.

OBJECTIVE

Our objective was to study the clinical characteristics of patients with cardiac syndrome X.

METHODS

Data of patients who underwent coronary angiography over a period of one year was retrospectively analyzed. Those with normal or non-obstructive coronaries in angiography with chest pain were included in this study.

RESULTS

1203 patients underwent coronary angiography during the study period. 105 (8.7%) patients fulfilled the inclusion criteria. There were 52 (49.5%) males and 53 (50.5%) females including 31 (29.5%) postmenopausal women. Many patients had atherosclerotic risk factors. Typical angina and atypical chest pain were reported by 63 (60%) and 42 (40%) patients, respectively. ECG was normal in 46 (43.8%) and abnormal in 59 (56.2%) patients. The most common abnormal finding in ECG was ST-T changes seen in 49 (46.7%) patients. Regional wall motion abnormality with mild left ventricular systolic dysfunction was seen in 4 (3.8%) patients while 101 (96.2%) patients had normal ventricular function in echocardiography. TMT was positive for inducible ischemia in 35 (33.3%) patients and inconclusive in 10 (9.5%) patients. Angiography showed normal epicardial coronaries in 85 (80.9%) patients.

CONCLUSIONS

Cardiac syndrome X constitutes a significant subset of patients undergoing coronary angiography. It is essential to identify and treat them specifically for microvascular angina. Many of them have atherosclerotic risk factors but their presentation is different from those with obstructive coronaries.

Circulating adipokines and insulin resistance in subjects with combined cardiac and metabolic syndrome X

BACKGROUND

Cardiac syndrome X (CSX) is characterized by angina pectoris but with patent coronary arteries. Our previous study showed that CSX subjects had decreased serum adiponectin but higher leptin and insulin resistance (IR). However, few studies have investigated circulating adipokines and IR in subjects with combined metabolic syndrome X (MetX) and CSX.

METHODS

Fifty-nine subjects with CSX were retrospectively enrolled from our cardiac catheterization patient databank. Fifty-four subjects with valvular heart disease or arrhythmia and with normal coronary angiograms were recruited as the non-CSX comparison group. The study subjects were reclassified according to the presence or absence of MetX. Circulating adipokines and degree of IR were measured.

RESULTS

Subjects with combined MetX and CSX had a significantly higher HOMA-IR, a higher circulating leptin level (median 8.7 vs. 3.3 ng/mL, p < 0.001), but a lower circulating adiponectin level (median 2.8 vs. 12.3 μg/mL, p < 0.001) than those without MetX and CSX. In pairwise comparisons, combined MetX and CSX subjects had a similar circulating adipokines and IR index as those who had only either one syndrome X. In a multivariate regression analysis, serum triglycerides (odds ratio 1.011, p = 0.024) and hypertension (odds ratio 14.453, p = 0.003) were independently associated with diagnosis of combined MetX and CSX.

CONCLUSIONS

Combined MetX and CSX had a significantly higher HOMA-IR, a higher circulating leptin but a lower circulating adiponectin level than those without MetX and CSX. Combined syndrome X did not confer more changes on adipokines or IR index comparing with those with only one syndrome X.

Microvascular coronary dysfunction and ischemic heart disease: where are we in 2014?

Many patients with angina and signs of myocardial ischemia on stress testing have no significant obstructive epicardial coronary disease. There are many potential coronary and non-coronary mechanisms for ischemia without obstructive epicardial coronary disease, and prominent among these is coronary microvascular and/or endothelial dysfunction. Patients with coronary microvascular and/or endothelial dysfunction are often at increased risk of adverse cardiovascular events, including ischemic events and heart failure despite preserved ventricular systolic function. In this article, we will review the diagnosis and treatment of coronary microvascular and endothelial dysfunction, discuss their potential contribution to heart failure with preserved ejection fraction, and highlight recent advances in the evaluation of atherosclerotic morphology in these patients, many of whom have non-obstructive epicardial disease.

Mental symptoms in patients with cardiac symptoms and normal coronary arteries

Objectives

Patients with chest pain and normal coronary arteries often suffer from physical and psychological symptoms. Therefore, this study aimed to examine the incidence of mental symptoms in patients with angiographic exclusion of a coronary heart disease.

Design

In 253 patients with angiographic exclusion of a coronary heart disease the type and intensity of their symptoms were evaluated before and after coronary angiography. In addition, the incidence of psychopathological symptoms was quantified by standardised questionnaires such as general anxiety and depression (HADS), heart-focused anxiety (CAQ), hypochondria (Whiteley Index) and somatoform disorder (SOMS) and quality of life (SF-12). Finally, the incidence of psychological symptoms in these patients was compared to the incidence in the normal population.

Results

Despite the absence of a coronary artery disease, 70% of patients continue to suffer from cardiac symptoms. The incidence of general anxiety was increased by 37% in women and by 22% in men in comparison to the normal population. Heart-focused anxiety was raised by 27%. Somatoform disorder appeared 120% more often in patients after cardiac catheterisation in comparison to the normal population. In addition, the incidence of hypochondria was elevated by 68% in patients after coronary angiography compared to normal population. This increased appearance of psychological symptoms was reflected in a significantly lower quality of life (SF-12) in patients with inconspicuous coronary angiography.

Conclusions

Patients with cardiac symptoms and normal coronary arteries more often suffer from mental symptoms in comparison to the healthy population.

Thermodilution-derived coronary microvascular resistance and flow reserve in patients with cardiac syndrome X

BACKGROUND

Although increased coronary microvascular resistance (CMR), resulting in coronary microvascular dysfunction, is speculated to be responsible for myocardial ischemia in patients with cardiac syndrome X (CSX), it has never been directly demonstrated, and the correlation between CMR and severity of myocardial ischemia has not been elucidated in this setting. This study aimed to ascertain the increased CMR directly and to explore the relationship between CMR and severity of ischemia in patients with CSX.

METHODS AND RESULTS

We studied 18 patients with CSX and 18 age- and sex-matched control subjects. Thermodilution-derived coronary flow reserve and index of microvascular resistance were measured using a pressure-temperature sensor-tipped coronary wire. Exercise treadmill test was performed by the Bruce protocol for calculating Duke treadmill score. Coronary flow reserve was significantly lower (2.37±0.81 versus 3.68±0.72; P<0.001) and index of microvascular resistance was higher (33.1±7.9 versus 18.8±5.6 U; P<0.001) in patients with CSX compared with those in control subjects. The Duke treadmill score was correlated positively to coronary flow reserve (r=0.539; P=0.021) and negatively to index of microvascular resistance (r=-0.742; P<0.001) in patients with CSX.

CONCLUSIONS

Using an intracoronary thermodilution method, we for the first time directly demonstrated an increased microvascular resistance in patients with CSX. Furthermore, severity of ischemia was found to be intimately associated with CMR in this setting.

Deficiency of a new protein associated with cardiac syndrome X; called adropin

The pathophysiology of cardiac syndrome X (CSX) is still unclear, but most patients with CSX have endothelial dysfunction. It has been shown that adropin uniquely effects the regulation of endothelial function. The purpose of the study was to evaluate the role of adropin in CSX. Eighty-six consecutive cardiac syndrome X-diagnosed patients and 86 age-sex matched healthy subjects were enrolled into the study. Serum adropin levels, nitrite/nitrate levels were measured in each subject. The adropin levels were significantly lower in patients with CSX than healthy subjects (1.7 ± 0.8 ng/mL and 3.4 ± 1.8 ng/mL, respectively; P < 0.001). The BMI values of patients with CSX were significantly higher than control subjects (28.1 ± 2.4 kg/m(2) and 26.0 ± 3.7 kg/m(2) , respectively; P < 0.001). Plasma nitrite/nitrate levels were lower in patients with CSX than control subjects (15.9 ± 1.6 μmol/L vs. 25.4 ± 2.8 μmol/L, respectively; P < 0.001), and they have a significantly positive correlation with plasma adropin levels (r = 0.463, P < 0.001). In the multiple linear regression analysis, nitrite/nitrate levels, BMI, and adropin were found to be independent risk factors for CSX. A ROC curve is used to identify the ability of adropin levels to predict the cardiac syndrome X. The area under the ROC curve was 0.854 for adropin levels (P = 0.0001). The sensitivity and specificity values of adropin levels were 90.7 and 70.9%, respectively (cut-off value 2.73). In conclusion, lower serum adropin levels were associated with CSX. Adropin is an independent risk factor for CSX.

Altered transmural contractility in postmenopausal women affected by cardiac syndrome X

BACKGROUND

Cardiac syndrome X (CSX) is characterized by typical angina and abnormal exercise test results, with normal coronary arteries. Cardiovascular magnetic resonance imaging has shown subendocardial hypoperfusion in patients with CSX after adenosine. The aim of this study was to investigate the contribution of separate myocardial layers to global function under stress in women with CSX.

METHODS

Twenty-two postmenopausal women with CSX were studied and compared with 20 healthy women matched for age and body mass index. All subjects underwent clinical evaluations and exercise echocardiography. Left ventricular systolic and diastolic parameters were evaluated at rest and at peak exercise. Layer-specific global longitudinal strain (GLS) and strain rate (SR) were assessed from the endocardium, midmyocardium, and epicardium using two-dimensional speckle-tracking echocardiography.

RESULTS

All subjects showed normal contractile function at rest and at peak exercise. Significant increases in GLS and SR in all myocardial layers were observed at peak exercise in the control group, whereas patients with CSX showed significantly lower increases in endocardial GLS and SR compared with the control group (endocardial ΔSR, 0.17 ± 0.19 vs 0.33 ± 0.13 [P < .01]; endocardial ΔGLS, 1.33 ± 2.93 vs 6.64 ± 2.62 [P < .001]). Moreover, significantly impaired diastolic function (ΔE', 1.1 ± 3.3 vs 4.0 ± 2.03) was observed in patients with CSX.

CONCLUSIONS

The results of this study show subendocardial impairment of contractile function during exercise in patients with CSX, confirming the existence of reduced myocardial perfusion reserve in patients with CSX and suggesting layer-targeted exercise echocardiography as a sensitive diagnostic tool in the assessment of suspected CSX.