Impaired Left Ventricle Filling in Slow Coronary Flow Phenomenon: An Echo-Doppler Study

Changes of left atrial morphology and function evaluated with four-dimensional automated left atrial quantification echocardiography in patients with coronary slow flow phenomenon and preserved left ventricular ejection fraction

BACKGROUND

Coronary slow flow phenomenon (CSFP) can cause left ventricular diastolic dysfunction (LVDD). In multiple studies, the left atrial (LA) strain has been reported to be an excellent parameter for assessing LVDD. The 4-dimensional automated LA quantification (4D Auto LAQ) dedicated to the LA was recently available. Our study aimed to evaluate subclinical changes in LA morphology and function with 4D Auto LAQ in patients with CSFP and preserved left ventricular ejection fraction (LVEF).

METHODS

Forty-eight patients with CSFP confirmed with coronary angiography and 46 age and gender-matched controls with normal coronary flow were enrolled. The thrombolysis in myocardial infarction frame count (TFC) method was used to record coronary blood flow velocities for each major coronary artery. LA volume, LA longitudinal and circumferential strains during each of the three LA phases (reservoir, conduit, and contraction), LA total emptying fraction (LATEF), LA active emptying fraction (LAAEF), and LA passive emptying fraction (LAPEF) were quantified with 4D Auto LAQ analysis.

RESULTS

Compared with controls, LA longitudinal reservoir strain (LASr), LA longitudinal strain during the conduit phase (LAScd), LA contraction strain (LASct), LA conduit circumferential strain (LAScd-c), LATEF, LAPEF decreased significantly in individuals with CSFP. Of the 4D- LAQ parameters, only LASr [odds ratio (OR): 0.773, P < 0.001] and LATEF [OR: 0.762, P < 0.001] were associated with CSFP in multivariate analysis. A LASr ≤23.00% can differentiate CSFP from controls [sensitivity, 66.7%; specificity, 93.5%; area under the curve (AUC), 0.823; P < 0.001]. A LASr of ≤19.00% could predict the elevation of LV filling pressure in the CSFP cohort [sensitivity, 76.9%; specificity, 74.3%; area under the curve (AUC), 0.792; P < 0.001]. LASr was the only index to demonstrate significant changes compared to controls in single-vessel CSFP. Compared to the right coronary artery (RCA) and left circumflex (LCX), TFC of the left anterior descending (LAD) artery was the only independent variable of LASr (Standardized Coefficients: -0.386, P = 0.037).

CONCLUSIONS

Impairment of LA reservoir function reflected by changes in LASr and LATEF can be seen in patients with CSFP. LASr could predict the elevation of LV filling pressure in CSFP individuals. LASr is more sensitive than LATEF in detecting LA reservoir dysfunction in single-vessel CSFP. CSFP in LAD exerts a more prominent influence on LASr than RCA or LCX.

Prolonged P Wave Peak Time May Be a Sign of LV Diastolic Dysfunction in the Coronary Slow Flow Phenomenon

BACKGROUND

The coronary slow flow phenomenon (CSFP) is an atherosclerotic process that causes ischemia at the microvascular level. The CSFP may affect P wave durations, especially P wave peak time (PWPT), by microvascular ischemia, left ventricular diastolic dysfunction, and changes in the left atrial dimension. Therefore, in the present study, we aimed to assess PWPT in the CSFP.

METHOD

One hundred and ninety-five patients were included in this single-center, retrospective study. Ninety patients were enrolled in the CSFP group and 105 patients in the control group. PWPT was defined as the duration between the beginning and peak of the p wave and obtained from the leads Dıı and V _ı.

RESULTS

The mean age of the study population was 48.5 ± 9.5, and 108 (55.3%) of the patients were female. We found PWPT was longer in the CSFP group than in the control group. Correlation analysis showed a positive correlation between PWPT in both leads (D _II, V _ı) and left atrial anterior-posterior diameter, mean TIMI frame count (TFC), and E/e. A significant relationship was observed between mean TFC, E/e, EF, heart rate, and PWPT in lead D _ıı (β coefficient = 0.33, 95% CI 0.44-1.33, p < 0.001, β coefficient = 0.23, 95% CI 0.25-1.85, p=0.01, β coefficient = -0.140, 95% CI -1.04--0.53, p=0.03, and β coefficient = -0.13, 95% CI -0.29--0.014, p=0.03, respectively) in multivariable linear analysis.

CONCLUSION

In the present study, we found prolonged PWPT in patients with the CSFP and found a relationship between PWPT and mean TFC.

Evolution of Diastolic Dysfunction in Patients with Coronary Slow Flow Phenomenon and Acute Non-ST Segment Elevation Myocardial Infarction

BACKGROUND

Diastolic function has been reported to be impaired in many patients with coronary slow flow phenomenon (CSFP). CSFP has broad spectrum of clinical presentations, including non-ST elevation myocardial infarction (NSTEMI). We sought to study the short-term evolution of diastolic function in CSFP patients presenting with NSTEMI.

METHODS

This study included 92 patients with CSFP and acute NSTEMI. Conventional echocardiography Doppler imaging and tissue Doppler echocardiography imaging were used to evaluate diastolic function during index NSTEMI and after 3 months.

RESULTS

Mean age of study patients was 45.7 ± 6.8 years. The prevalence of diastolic dysfunction (DD) at baseline was 69 patients (75%) and 28 patients (30.4%) at 3 months, p < 0.001. Various diastolic function indices showed significant improvement from baseline to 3 months follow-up. E/Em was 17.32 ± 3.41 at baseline compared to 12.41 ± 5.58 at 3 months, p = 0.039. Septal e' velocity was 5.67 ± 4.56 cm/s at baseline compared to 7.78 ± 3.22 cm/s at 3 months, p = 0.023. Medications used were not significantly different between those with improved versus unimproved DD.

CONCLUSIONS

Diastolic function seems to improve over short-term follow-up in patients with CSFP presenting with NSTEMI. This could reflect a transient worsening during acute NSTEMI.

Echocardiographic Evaluation of Left and Right Ventricular Function in Patients with Coronary Slow Flow Syndrome: A Comparative Study

The Coronary Slow Flow Phenomenon is a syndrome of normal coronary anatomy and delayed progression of contrast medium through the coronary vessels. This research attempts to analyze and compare the systolic and diastolic function of the left and right ventricle in primary Slow Flow and Normal Coronary Flow.Two groups of primary Slow Coronary Flow (33 people) and Normal Coronary Flow (11 people) were included and the systolic and diastolic function of the ventricles was analyzed and compared between them.In the control group 18% of patients had mild and in the case group 24.2% mild, and 3.1% had moderate left ventricular diastolic dysfunction (P >0.05). The frequency distribution of the left and right ventricular systolic dysfunction was similar in the two groups.There was no statistically significant difference between two groups and in the association of cardiac dysfunction, it may be reasonable to investigate other causes.

The relationship between coronary slow flow phenomenon and carotid femoral pulse wave velocity and aortic elastic properties

Introduction

In this study, we aimed to investigate the relationship between coronary slow flow (CSF) and carotid-femoral pulse wave velocity (CFPWV).

Methods

78 (27 women, mean age 43.95 ± 7.28) patients with CSF, and 70 (22 women, mean age 44.34 ± 7.08) healthy individuals were included in the study. Arterial stiffness measurement was performed to both groups via CFPWV, which is considered the gold standard. Aortic elastic properties (ASI-β and aortic distensibility) were evaluated in both groups.

Results

The CSF group had significantly higher CFPWV and aortic distensibility values and significantly lower ASI-β values compared to the control group. There was a positive correlation between TIMI frame count (TFC) obtained in all coronary arteries and CFPWV and aortic distensibility, and a negative correlation between TFC and ASI-β. It was determined that CFPWV predicted CSF with 97% specificity and 98% sensitivity at a 7.68 cut-off value (ROC area = 994, p < 0.001). ASI-β was determined to predict CSF with 64% specificity and 47% sensitivity at a 2.98 cut-off value (ROC area = 047, p < 0.001). Aortic distensibility was determined to predict CSF with 76% specificity and 79% sensitivity at a 3.94 cut-off value (ROC area = 706, p < 0.001).

Conclusion

Arterial stiffness increases in CSF patients, suggesting that CSF is a systemic pathology rather than a local disease and that a systemic cause such as atherosclerosis plays a role in etiology.

Ventricular Dysfunction in Patients with Coronary Slow-Flow Phenomenon: A Single-center Case-control Study

Background:

Coronary slow-flow phenomenon (CSFP), characterized by delayed distal vessel opacification of contrast, in the absence of significant epicardial coronary stenosis, has effects on exercise capacity and clinical outcomes. The aim of this study was to explore the systolic and diastolic function of patients with CSFP and to compare it with a group of controls with normal coronary anatomy and flow.

Materials and Methods:

In this case–control study, 45 consecutive CSFP patients and 45 age-, body mass index-, and presentation season-matched controls with normal coronary arteries and normal coronary flows were enrolled from Seyyedoshohada Heart Center from March 2015 to March 2016. A transthoracic echocardiography was done by a blinded echocardiographer using both conventional and tissue Doppler imaging techniques.

Results:

Patients with CSFP were more likely to be male (P = 0.006) and smoker (P = 0.02) compared to controls. Other risk factors were not different between the two groups. There were no differences between groups in terms of the peak early (E) and late (A) diastolic velocities, deceleration time, early (E’) and late (A’) peak diastolic velocities at the mitral annulus, and the systolic mitral annular velocity (S’). Global longitudinal strain and peak systolic strain rates was lower in patients with CSFP compared to controls (−16.7% ±2.4% vs. −18.9% ±1.6%, P < 0.001 and 1.10 ± 0.1 vs. 1.24 ± 0.3, P = 0.008, respectively).

Conclusion:

Patients with CSFP showed signs of the left ventricular systolic dysfunction in tissue Doppler echocardiography, which underlines the importance of close follow-up in these patients. Patients with CSFP should be screened for ventricular function preferably by tissue Doppler echocardiography.

Admission homocysteine is an independent predictor of spontaneous reperfusion and early infarct-related artery patency before primary percutaneous coronary intervention in ST-segment elevation myocardial infarction

Background

Spontaneous reperfusion (SR) and early infarct related artery (IRA) patency before primary percutaneous coronary intervention (PPCI) might bring extra benefit for patients with ST-segment elevation myocardial infarction (STEMI). This study premilinarily screened the independent predictors of SR, and assessed the relationship between SR and plasma homocysteine (HCY).

Methods

The medical records of 998 patients who were diagnosed as STEMI and underwent emergency coronary angiography were retrospectively studied, SR was defined as achievement of TIMI grade 3 flow in the IRA before PCI. The baseline characteristics, clinical manifestations and hematological variables were compared between SR and NSR group. Optimal cutoff point of HCY was calculated with receiving operating characteristics (ROC) analysis, multivariate logistic regression models were used to identify predictors of SR.

Results

229 (22.95%) patients showed angiographic SR. For HCY, the area under the curve was 0.70 (95% CI: 0.63–0.77, P = 0.034), the optimized cut off point was 17.55 μmol/L. Preinfarct angina (95% CI: 1.61–5.65, P = 0.0005), plasma C-reactive protein (CRP) level (95% CI: 0.87–0.99, P = 0.016) and HCY < 17.55 μmol/L (95% CI: 2.43–8.72, P < 0.0001) were found to be independent predictors for SR.

Conclusion

In patients with STEMI, HCY < 17.55 μmol/L, preinfarct angina and plasma CRP level were independent predictors of SR.

Effect of Coronary Slow Flow on Intrinsicoid Deflection of QRS Complex

Coronary slow flow is a rare, clinically important entity observed in acute coronary syndrome. The pathophysiological mechanism is not fully elucidated. We investigated patients with chest pain who had angiographic features consistent with the coronary slow flow. One hundred ten patients were included. Electrocardiography, echocardiography, and angiography results were retrospectively noted. The mean age was 56.4. Fifty-eight were male, and fifty-two were female. The control group consisted of patients with normal angiography. Patients had higher diastolic blood pressure, lower mean ejection fraction, higher average left ventricular end-diastolic diameter, and higher mean left atrial size than the control group (p=0.009, p=0.017, p=0.041, andp < 0.001, resp.). Patients had higher average V1 ID, V6 ID, P wave dispersion, TFC LAD, TFC Cx, TFC RCA, and TFC levels than the control group. A significant linear positive relationship was found between the V1 ID and the TFC LAD, TFC Cx, TFC RCA, and TFC; also between the V6 ID and the TFC LAD, TFC Cx, TFC RCA, and TFC. Angiographic and electrocardiographic features are suggestive and diagnostic for the coronary slow flow syndrome. Although when regarded as a benign condition, coronary slow flow should be diagnosed, followed up, and treated as many of laboratory features suggest ischemic events.

Is dipyridamole useful in improving left ventricular systolic and diastolic function in patients with coronary slow flow?

BACKGROUND

Coronary slow flow (CSF) is an angiographic finding characterized by delayed opacification of epicardial coronary arteries without obstructive coronary disease. Previous studies have shown greater impairment of left ventricular (LV) systolic and diastolic function in patients with CSF. We aimed to examine the effect of dipyridamole on these functions.

METHODS

Our study included 40 patients with CSF and 40 subjects with normal coronary arteries. Conventional echocardiography Doppler imaging (CDI) and tissue Doppler echocardiography imaging (TDI) were used to evaluate LV systolic and diastolic function before and 2 months after treatment with dipyridamole.

RESULTS

Using CDI, we observed that early diastolic velocity (E) was significantly lower in patients with CSF, while late diastolic velocity (A), E/A ratio, isovolumic relaxation time, and myocardial performance index (MPI) were significantly higher in CSF patients compared with controls. Similarly, while early myocardial velocity (Em) was significantly lower, late myocardial velocity (Am), Em/Am ratio, isovolumic relaxation time (IRT), and MPI were significantly higher in CSF patients according to TDI measurements. Although there was no significant improvement in conventional Doppler parameters, there was significant normalization in tissue Doppler parameters after treatment with dipyridamole.

CONCLUSION

Left ventricular systolic and diastolic function may be negatively affected by CSF. Dipyridamole may improve these functions, especially at the tissue level.

Evaluation of Left and Right Atrial Function in Patients with Coronary Slow-Flow Phenomenon Using Two-Dimensional Speckle Tracking Echocardiography

BACKGROUND

Coronary slow-flow phenomenon (CSFP) is an angiographic diagnosis characterized by delayed coronary opacification in the absence of obstructive coronary artery disease. Currently, several investigators are focusing on ventricular function assessment in patients with CSFP; however, there is a paucity of data on their atrial function. This study was performed to evaluate left atrial (LA) and right atrial (RA) function in patients with CSFP.

MATERIALS AND METHODS

Eighty-two patients with CSFP and 55 controls without CSFP were enrolled in the study. Diagnosis of CSFP was made by thrombolysis in myocardial infarction frame count (TFC). The LA and RA global longitudinal strain and strain rate during systole (Ss, SRs), during early diastole (Se, SRe), and during late diastole (Sa, SRa) were measured using two-dimensional speckle tracking echocardiography.

RESULTS

In the CSFP group, LA Se and SRe decreased, while LA Sa and SRa increased, compared with the control group. RA Se and SRe were lower in patients with CSFP than in the controls.

CONCLUSIONS

LA conduit function decreased in patients with CSFP, while contractile function increased. RA conduit function also decreased in patients with CSFP.

Nicorandil improves myocardial function by regulating plasma nitric oxide and endothelin-1 in coronary slow flow

BACKGROUND

Coronary slow flow (CSF) is a special coronary microvascular disorder. The pathogenesis and effective therapeutics of CSF remain unclear. This study aimed to evaluate the global and regional functions of the left ventricle (LV) and investigate the efficacy of nicorandil in patients with CSF.

PATIENTS AND METHODS

Thirty-six patients with CSF in the left anterior descending (LAD) branch and 20 patients with normal coronary arteries were included. Global and regional functions of the LV supplied by LAD were measured using conventional Doppler echocardiography and two-dimensional speckle tracking echocardiography, respectively, within 24 h after coronary angiography. Concentrations of plasma nitric oxide (NO) and endothelin-1 (ET-1) were detected using colorimetry and radioimmunoassay, respectively. The function of the LV and the levels of NO and ET-1 were also investigated before and 90 days after treatment with 15 mg/day of nicorandil.

RESULTS

Compared with the control group, the early diastolic peak velocity (E), E/A ratio, and plasma NO levels were lower, whereas the late diastolic peak flow velocity (A) and plasma ET-1 levels were significantly higher in the CSF group (P<0.05). The longitudinal strain rate peak of the LV was reduced significantly in CSF patients (P<0.001). After treatment, 75% (27/36) of CSF patients were free of chest pain. The values of E peak, E/A ratio, longitudinal strain rate peak, and plasma NO level were increased (P<0.001), whereas the ET-1 level was decreased in CSF patients (P<0.001).

CONCLUSION

Nicorandil may improve chest pain symptoms and the impaired function of the LV, possibly by increasing plasma NO and reducing ET-1 in CSF.

Mean platelet volume is not associated with coronary slow flow: a retrospective cohort study

Objective:

To investigate mean platelet volume (MPV) levels in patients with coronary slow flow (CSF).

Methods:

465 stable angina pectoris cases with angiographically normal coronary arteries were recruited [coronary slow flow group (n=76), control group (n=389)] in the observational retrospective cohort study. Clinical, biochemical and demographic variables including MPV were noted and coronary blood flow was assessed with TIMI frame count (TFC).

Results:

Gender, smoking, height, serum creatinine, uric acid levels, hemoglobin, waist/hip ratio, systolic blood pressure but not MPV were significantly different among groups. Independent predictors of CSF were height (p=.029) and serum uric acid level (p=.045). Gender, height, weight, hip circumference, systolic blood pressure, fasting blood glucose, serum urea, creatinine, uric acid levels, hemoglobin and platelet count were associated with mean TFC whereas independent predictors of mean TIMI frame count were height (p=.010) and serum uric acid level (p=.041).

Conclusion:

Height and serum uric acid level but not MPV were independent predictors of both CSF and mean TFC.

Coronary slow flow: Benign or ominous?

Objective:

Coronary slow flow phenomenon has been arbitrarily defined as delayed coronary blood flow in the absence of obstructive coronary artery disease. The present study sought to investigate the clinical features, natural history, and outcomes of affected patients.

Methods:

In this prospective cross-sectional study, 217 consecutive patients who had undergone coronary angiography and showed features of coronary slow flow phenomenon were evaluated for demographic and coronary risk factor profile, as well as clinical outcomes, at baseline and following treatment.

Results:

The study population consisted of 165 (76%) males and 52 (24%) females. The mean age of patients was 52.6±10 years. Mean ejection fraction was 48.2±5.4, 39.3% had diabetes, 43.3% had hypertension, 49.8% was a cigarette smoker, 41.9% had dyslipidemia, and 15% had a familial history of cardiac disease. Forty-nine percent was detected to have abnormal hsCRP levels. The most prevalent presenting complaint was atypical chest pain. Fifty-four percent of patients had slow blood flow in all three vessels. Thirty-six people had undergone repeat coronary angiography in a follow-up period of 5-7 years due to persisting or worsening clinical symptoms, of whom 6 (16.6%) showed significant coronary artery stenosis. Eight (22.2%) had mild CAD, and the rest still showed coronary slow flow without significant stenosis. The most common complaint during follow-up and after initiation of medical therapy was nonanginal chest pain.

Conclusion:

Patients with coronary slow flow phenomenon are predisposed to atherosclerosis and obstructive coronary artery disease. Therefore, this pathology should not be considered as a totally benign condition. Primary and secondary cardiovasculature preventive measures should be constituted and seem worthwhile in this patient population.

Plasma factor XI and XII activity in patients with slow coronary flow

The exact pathophysiology of slow coronary flow (SCF) phenomenon, characterized by delayed opacification of coronary arteries during coronary angiography, is still unknown, although endothelial dysfunction, inflammation, vasomotor disorders and atherosclerosis are shown. The present study was conducted to investigate whether there is a coagulation pathway abnormality in patients with SCF measuring plasma factor XI and XII activity. The study included 55 patients with angiographically proven SCF (group I) and 40 individuals with normal coronary flow (NCF, group II). Baseline demographic properties were similar in both groups. Echocardiographic parameters were also similar in patients with SCF and NCF. Factor XI activity was significantly higher in group I when compared with group II. Factor XII activity was also significantly higher in group I when compared with group II (108.9 ± 19 vs. 98.8 ± 20, P = 0.018 and 131.2 ± 17 vs. 119.1 ± 16, P = 0.001, respectively). We conclude that SCF phenomenon appears to be associated with enhanced procoagulant state, which may support the role of inflammation and atherosclerosis in the pathogenesis of this phenomenon.

The effect of slow coronary flow on right and left ventricular performance

OBJECTIVE

To evaluate left and right ventricular functions using tissue Doppler echocardiography (TDE) and myocardial performance index (MPI) methods in patients with slow coronary flow (SCF) and to determine the relationship between these parameters and thrombolysis in myocardial infarction frame count in SCF patients.

SUBJECTS AND METHODS

Thirty-five patients (20 males and 15 females) with SCF who underwent coronary angiography and 35 age- and sex-matched controls (14 males and 21 females) without SCF who underwent elective coronary angiography were enrolled in the study. Left ventricular (LV) and right ventricular (RV) functions were examined using conventional echocardiography and TDE.

RESULTS

LV systolic myocardial velocity (Sm), early myocardial velocity (Em), late myocardial velocity (Am), and Em/Am ratio were similar in both the SCF and control groups; however, isovolumetric relaxation time (IRT) was higher in the SCF group compared to the control group (IRT: 99 ± 17 vs. 88 ± 20; p = 0.01). In patients with SCF, LV MPI was higher than in the control group, but this was not statistically significant (0.61 ± 0.11 vs. 0.56 ± 0.12; p = 0.07). The RV tricuspid annular velocities and MPI were similar in the SCF and control groups.

CONCLUSION

This study showed that SCF affected LV functions echocardiographically and could cause partially reduced LV performance. In addition, SCF did not affect RV functions echocardiographically.

Correlation between systolic deformation and dyssynchrony indices and the grade of left ventricular hypertrophy in hypertensive patients with a preserved systolic ejection fraction undergoing coronary angiography, based on tissue Doppler imaging

OBJECTIVES

The purpose of this study was to investigate whether systolic mechanical dyssynchrony occurs in hypertensive patients with a normal coronary artery and a normal ejection fraction and its relationship with different degrees of left ventricular (LV) hypertrophy.

METHODS

A total of 125 angiographically normal coronary patients (42.4% male; mean age ± SD, 57.16 ± 8.26 years) with an ejection fraction greater than 50% were included, of which 84 were hypertensive and 41 normotensive. The hypertensive patients were categorized into 3 groups: no, mild, and moderate LV hypertrophy. Tissue Doppler and deformation imaging parameters were measured in the 6 LV basal segments at peak systole.

RESULTS

The frequency of dyssynchrony was 40.5% in the hypertensive patients compared to 19.5% in the control patients (P = .020). Among the hypertensive patients, LV dyssynchrony was found in 5 patients (20%) with no hypertrophy, 20 (42.6%) with mild hypertrophy, and 9 (75%) with moderate hypertrophy. There was a moderate correlation between the grade of hypertrophy and septal-lateral wall delay (r = 0.497), 6-basal segment delay (r = 0.454), overall strain (r = 0.453), overall peak systolic velocity (r = -0.430), and standard deviation of the time to peak systolic velocity in the basal segments (r = 0.429). After adjustment for the LV end-systolic diameter and body surface area, overall strain was the best correlate of the hypertrophy grade (odds ratio, 7.043; 95% confidence interval, 1.839-26.980; P = .0044).

CONCLUSIONS

Among tissue Doppler and deformation indices, overall peak systolic strain was the strongest correlate of the LV hypertrophy grade. Therefore, in hypertensive patients with normal cardiac systolic function, a reduction in overall strain in the 6 basal LV segments may be a good indicator of progression of the LV hypertrophy grade and systolic dysfunction.

Impaired cerebral circulation in patients with slow coronary flow

Slow coronary flow (SCF) is characterized by delayed opacification of coronary arteries during coronary angiography and is associated with myocardial perfusion abnormalities, ischemia or myocardial infarction. We hypothesized that SCF could be a part of systemic circulatory abnormalities. Therefore, the present study was conducted to investigate whether cerebral blood flow velocity is altered in patients with SCF. The study included 16 patients suffering from chest pain with angiographically proven SCF and 16 subjects suffering from atypical chest pain with angiographically normal coronary flow. All study subjects were selected among those who undergone routine cardiac catheterization. SCF was defined based on thrombolysis in myocardial infarction frame count that reflects coronary artery flow. Thrombolysis in myocardial infarction frame count was significantly higher in patients with SCF than those with normal coronary flow. The average peak systolic, end diastolic and mean flow velocities of the middle cerebral artery were measured and recorded in both groups by transcranial Doppler ultrasonography. Baseline demographic properties were similar in both groups. Echocardiographic parameters were also similar in patients with SCF and those with normal coronary flow. In contrast, both right and left middle cerebral artery peak systolic, end diastolic and mean flow velocities were significantly lower in patients with SCF than those with normal coronary flow. We conclude that cerebral blood flow velocity is significantly lower in patients with SCF. SCF phenomenon may reflect a part of impaired systemic circulation.

The effects of perindopril on QT duration and dispersion in patients with coronary slow flow

Coronary slow flow (CSF) is characterized by delayed opacification of coronary arteries in the absence epicardial occlusive disease. QT duration and dispersion have been reported to be longer in patients with CSF. ACE inhibitors may improve CSF through positive effects on endothelial function. The study included 32 patients having CSF and 25 subjects having normal coronary arteries in coronary angiography. The patients were evaluated with 12-leads electrocardiography and echocardiography before and 3 months after treatment with perindopril. Compared to the control group, maximum corrected QT duration (QTcmax) (432.0 ± 28.9 vs. 407.0 ± 39.1 ms, p = 0.008) and QT dispersion (QTcD) (64.0 ± 16.5 vs. 37.3 ± 12.1 ms, p < 0.001), mitral inflow deceleration time (DT) (251.3 ± 49.4 vs. 218.8 ± 44.5 ms, p = 0.013), and isovolumetric relaxation time (IVRT) (115.8 ± 18.4 vs. 107.2 ± 22.9 ms, p < 0.001) were significantly longer and E/A ratio 0.85 ± 0.2 vs. 1.1 ± 0.3, p = 0.004) was lower in patients with CSF. QTcmax (to 407.0 ± 28.0 ms, p = 0.001), QTcD (to 44.5 ± 11.4 ms, p < 0.001), DT (to 221.6 ± 37.7 ms, p < 0.001) and IVRT (to 103.8 ± 16.1 ms, p < 0.001) were significantly decreased and E/A ratio (to 0.98 ± 0.3, p < 0.001) was significantly increased after treatment with perindopril. Coronary slow may be associated with prolonged QT interval and increased QT dispersion and impaired diastolic filling. Perindopril may be helpful in restoration of these findings.

Regional functions of the left ventricle in patients with coronary slow flow and the effects of nebivolol

Background: Microvascular and endothelial dysfunction have been implicated for coronary slow flow (CSF). Nebivolol, besides its beta-receptor blocking activity, causes an endothelium-dependent vasodilatation through increased nitric oxide release.

Methods: This study included 27 patients with CSF and 27 subjects with normal coronary arteries. Segmental functions of the left ventricle (LV) were assessed using myocardial tissue Doppler velocities before and 3 months after treatment with nebivolol 5 mg/day.

Results: Compared with the control group, mitral deceleration time (DT) was significantly longer, and E/A ratio, systolic velocity of lateral mitral annulus (Sm) and regional myocardial peak systolic and early diastolic velocities (V s, Vd) were significantly lower in patients with CSF. The reason for coronary angiography was typical angina in 21 (77.8%) and positive treadmill test in six (22.2%) CSF patients. There were significant correlations between presence of CSF in left anterior descending artery (LAD) with S m ( r =-0.404, p =0.002) and Vs in anterior ( r =-0.531, p < 0.001 ) and lateral ( r =-0.495, p < 0.001 ) segments and between presence of CSF in RCA and Vs in posterior segments ( r =-0.501, p < 0.001). Treatment with nebivolol significantly decreased blood pressures (128.5±12.5/82.5±8.8 to 119.8± 12.6/76.4± 7.4 mmHg, p < 0.001), DT (252.3±53.6 to 222.0±41.0 ms, p < 0.001 ) and IVRT (115.7±19.9 to 103.3±17.0 ms, p <0.001), and increased exercise capacity (8.7±1.3 to 10.4±0.9 METs, p < 0.001), E/A ratio (0.87±0.26 to 1.08±0.23, p <0.001) and myocardial velocities ( p < 0.001). All the patients were free of angina after treatment. Patients with CSF had impaired diastolic and regional LV functions.

Conclusions: Nebivolol may therefore be useful in improving angina, exercise capacity and LV functions in patients with CSF.

The "slow coronary flow" phenomenon: evidence of preserved coronary flow reserve despite increased resting microvascular resistances

INTRODUCTION

The expression "slow coronary flow phenomenon" (SCFP) indicates a slow progression of the contrast seen at the coronary angiography in the absence of epicardial stenosis and/or of other conditions associated with decreased coronary flow velocity. While microvascular abnormalities are suspected to underlie the mechanism of SCFP, they have never been directly demonstrated.

METHODS AND RESULTS

Fifteen anginal patients with a positive stress test and no evidence of epicardial lesions (obstructive coronary artery disease, coronary ectasia, or coronary spasm) were enrolled. In eight patients, the diagnosis of SCFP was made (TIMI frame count>average +2SD). All subjects underwent measurement of the coronary flow reserve (CFR) and the index of microvascular resistance (IMR) using an intracoronary thermodilution method (RADI medical systems). There was no difference between groups in age, cardiovascular risk factors, blood pressure and heart rate, coronary artery diameter and fractional flow reserve (an index of the presence of epicardial stenosis). At rest, microvascular resistances (mean transit timexdistal pressure) were significantly higher in the SCFP group (SCFP: 104+/-31 versus 53+/-27, P<0.01). Showing normal responsiveness to vasodilators, this difference was abolished after induction of hyperemia (SCFP group: 34+/-22; control: 22+/-15, P=ns); coronary flow reserve was normal in the subjects with the SCFP (3.6+/-1.6).

CONCLUSIONS

We provide the first human in vivo evidence that resting microvascular resistances are increased in patients with the SCFP. At the same time, showing an intact capacity to vasodilate, microvascular resistances were normal during hyperemia, and coronary flow reserve was not impaired in SCFP patients.

Relationship between Slow Coronary Flow and Left Atrial Appendage Blood Flow Velocities

AIMS

This study was undertaken to assess whether slow coronary flow (SCF)is related to low left atrial appendage (LAA) blood flow velocities.

METHODS

Study subjects consist of 44 patients with SCF and 11 volunteer subjects with normal coronary angiogram. The diagnosis of SCF was made using the TIMI frame count method. The blood flow velocities were obtained by placing a pulsed-wave Doppler sample volume inside the proximal third of the LAA.

RESULTS

The mean LAA emptying velocities (MEV)were significantly lower in patients than control subjects (34.5 +/- 9.9 cm/sec vs 84.0 +/- 12.1 cm/sec; P < 0.001). In bivariate analysis, significant correlation was found between MEV, and systolic pulmonary venous flow, mean TIMI frame count, deceleration time, and isovolumetric relaxation time (P < 0.05). By multiple linear regression analysis, mean TIMI frame count (beta=-0.865, P < 0.001) was identified as independent predictors of MEV.

CONCLUSION

This study indicates that SCF phenomenon may be related to low LAA blood flows.