Endothelial nitric oxide synthase gene polymorphisms in patients with slow coronary flow.

BACKGROUND AND AIMS: The aim of this study was to explore potential associations of the intron 4 variable number of tandem repeats (VNTR) and E298A polymorphisms of the endothelial nitric oxide synthase (eNOS) gene with slow coronary flow (SCF). The association between plasma nitrate and nitrite (NO x ) concentrations and eNOS gene polymorphisms was also assessed. MATERIALS AND METHODS: The intron 4 VNTR and E298A polymorphisms of the eNOS gene were evaluated in the isolated DNA blood samples obtained from the SCF patient group (n = 30) and healthy group consisted of age- and sex-matched controls (n = 61). RESULTS: Plasma NO x level was significantly lower in patients with SCF than in controls. In addition, patients with SCF have significantly lower nitric oxide levels than control subjects within each genotype variants. The allele and genotyped frequencies of the eNOS intron 4 VNTR and E298A polymorphisms were similar between patients with SCF and the controls. Plasma NO x concentrations with respect to the relevant genotypes were found insignificant. DISCUSSION AND CONCLUSION: Plasma NO x is lower in patients with SCF than in healthy subjects. Our findings may suggest the lack of association between intron 4 VNTR and E298A polymorphisms of the eNOS gene and SCF.

Teleconsultation of coronary angiograms using smartphones and an audio/video conferencing application.

OBJECTIVE: To examine the feasibility and accuracy of teleconsultation of coronary angiograms using iPhone 4 and FaceTime. METHODS: The study was conducted in two stages. Coronary angiograms of 100 patients with single-vessel disease were retrospectively selected by a core laboratory unit and then re-evaluated by a consultant cardiologist on both an iPhone 4 screen via the FaceTime application and on the workstation monitor of the angiography laboratory. The interpretations of the consultant cardiologist on localization and severity of angiographic lesions were recorded and compared with those of the core laboratory. Using the same teleconsultation system, the consultant cardiologist outside the hospital was presented live angiographic images of 10 patients undergoing primary percutaneous coronary intervention (PCI) for acute myocardial infarction. RESULTS: Interpretations of the consultant cardiologist on the localization and severity of 100 lesions on both the smartphone screen and workstation monitor showed high levels of agreement with the results of the core laboratory (for all, κ > 0.80). Of 10 patients whose PCI was performed under live video teleconsultation, eight patients underwent successful PCI while two patients had normal coronary arteries. There was an excellent agreement between the consultant cardiologist and the operator regarding lesion localization. CONCLUSIONS: Smartphones allow highly accurate interpretations on angiographic lesions and thus may serve as a supplementary teleconsultation tool in both elective and emergency situations.

Evaluation of blood rheology in patients with coronary slow flow or non-obstructive coronary artery disease.

Coronary slow flow (CSF) has been documented in 25% of patients evaluated for angina or angina-like chest pain, despite the presence of normal epicardial coronary arteries on angiography. The risk for the development of clinical events in patients with non-obstructive coronary artery disease (NOCAD) is higher than in patients with completely normal coronary arteries. The object of this study was to evaluate changes in blood and plasma viscosity in patients with CSF or NOCAD. The study included 147 subjects (CSF, n = 42, NOCAD, n = 42 and controls, n = 63). Blood and plasma viscosity, complete blood counts, fibrinogen, and high sensitivity C-reactive protein (hs CRP) levels were measured. There was no significant difference between the groups with respect to blood and plasma viscosity (p > 0.05). Hemoglobin, hematocrit, and erythrocyte counts were significantly higher in the CSF group compared to the NOCAD group (p = 0.017, p = 0.023 and p = 0.023 respectively) and the control group (p = 0.026, p = 0.02 and p = 0.02, respectively). High sensitivity CRP levels in the NOCAD group were higher than the CSF group and the control group (p = 0.001 and p = 0.018, respectively). In conclusion, no significant difference was observed in the blood and plasma viscosity in patients with CSF or NOCAD. Increases in hemoglobin and hematocrit values without an increase in viscosity may play a role in the pathophysiology of CSF.

Comparison of fibrinolytic versus surgical therapy in the treatment of obstructive prosthetic valve thrombosis: a single-center experience.

OBJECTIVE: Prosthetic heart valve thrombosis (PVT) is a rare but severe cardiac condition. There are only a few data regarding comparison of the fibrinolytic and surgical approaches for the treatment of PVT. In this study, we compared the results of fibrinolytic therapy versus surgery in patients who presented to our institution with a diagnosis of obstructive-type PVT. METHODS: From January 2001 to August 2008 in our institution, 33 patients who met clinical and echocardiographic criteria for obstructive-type PVT were included in the study. Fifteen of these patients underwent fibrinolytic treatment with streptokinase, which consisted of an initial bolus of 250,000 U followed by 100,000 U/h. Eighteen patients were treated with surgery. RESULTS: The 2 groups had similar baseline characteristics, including New York Heart Association functional status, types and positions of prosthetic valves, international normalized ratio values, and presentation symptoms. Full hemodynamic success was achieved in 12 patients who underwent fibrinolytic therapy and in 15 patients in the surgery group. The mean (±SD) streptokinase infusion time was 17.8 ± 11.1 hours. Two major hemorrhages and 2 cases of systemic embolism were observed in the fibrinolytic group. The 2 groups did not differ with respect to mortality rate (P = .79). The duration of hospitalization was longer in the fibrinolytic group than in the surgery group (10.7 ± 6.6 days versus 6.9 ± 6.7 days, P = .045). CONCLUSIONS: Although fibrinolytic therapy is generally recommended for the treatment of PVT for specific patient groups, our results suggest that it may be as efficacious and safe as surgery, depending on patient selection.

Short-term effects of fluvastatin therapy on plasma interleukin-10 levels in patients with chronic heart failure.

BACKGROUND: Experimental data demonstrated that inflammatory mediators, such as pro-inflammatory and anti-inflammatory cytokines and their receptors might have important role in the development and the progression of heart failure (HF). Statins were shown to downregulate inflammatory cytokines in HF. Interleukin (IL)-10 is one of the most important anti-inflammatory cytokines. The effect of statin therapy on plasma IL-10 levels is not known in patients with HF. We conducted this study to investigate the effects of fluvastatin therapy on plasma IL-10 cytokine concentration in patients with HF. METHODS: A total of 29 patients with ischemic HF were included in this prospective uncontrolled study. Patients were assigned to fluvastatin (80 mg/day) after baseline examinations. Determination of biochemical parameters including lipids, IL-10, and tumor necrosis factor-alpha were performed at baseline and 12 weeks after the initiation of fluvastatin therapy. All participants also underwent symptom-limited exercise tolerance test at baseline and 12 weeks, and heart rate recovery (HRR) was calculated. RESULTS: A significant elevation in the plasma levels of IL-10 after 12 weeks of fluvastatin treatment (4.8+ or -1.0 vs. 6.5+ or -1.3 pg/ml, P=0.002) was observed. Plasma tumor necrosis factor-alpha levels were significantly decreased after fluvastatin therapy (6.3+ or -2.3 vs. 4.8+ or -1.4 pg/ml, P=0.003). Fluvastatin therapy significantly improved HRR at 1 min after 12 weeks compared with baseline (19+ or -7 vs. 24+ or -9 bpm, P<0.001). A positive correlation between the change in the levels of IL-10 and the change in HRR at 1 min (r=0.57, P<0.001) was observed. CONCLUSION: Fluvastatin therapy might lead to an increase in plasma IL-10 levels and an associated improvement in vagal tonus as assessed by HRR at 1 min in patients with HF. These findings might partly explain the possible benefit observed in statin trials.

Coronary lesion type, location, and characteristics of acute ST elevation myocardial infarction in young adults under 35 years of age.

OBJECTIVE: In the present study, we attempted to analyze the coronary artery lesion characteristics of acute ST elevation myocardial infarction (STEMI) in young patients (aged less than 35 years). METHODS: We retrospectively surveyed 25 038 coronary angiography procedures, which were carried out at The Baskent University Adana Hospital from 1998 to present, to discover acute STEMI in young patients. We studied clinical risk factors and angiographic characteristics in 42 consecutive patients who underwent primary coronary angiography for acute STEMI. Control group (n=42) had no history of coronary artery disease and had angiographically proven normal coronary arteries. All patients were under 35 years of age. Angiographic features for STEMI group were collected and both groups were compared for coronary risk factors. RESULTS: Male sex was more prevalent in acute STEMI group when compared with control participants (83 vs. 59%, respectively; P=0.01). A significant difference was found in cigarette smoking (62 vs. 36%, respectively; P=0.007) and family history (33 vs. 16%, respectively; P=0.03) between the two groups. No statistical significance was observed between the groups in terms of hypertension, diabetes mellitus, total cholesterol, low-density lipoprotein cholesterol, and triglyceride levels. Mean high-density lipoprotein cholesterol level was 33+/-8 mg/dl in STEMI group and 39+/-12 mg/dl in control participants (P=0.02). Young patients with acute STEMI showed a preponderance of single-vessel disease (69%) and acute anterior STEMI (60%) owing to occluded left anterior descending artery (P<0.001). CONCLUSION: We observed risk factors such as family history, smoking, and low high-density lipoprotein cholesterol levels in young adults. Acute anterior STEMI owing to occluded left anterior descending artery was more frequent. Coronary atherosclerosis was characterized by higher presence of type B and proximal lesions. The handling selection was percutaneous coronary intervention in more than half of the patients.

An unusual cause of mismanagement in an acute myocardial infarction case: pseudothrombocytopenia.

Thrombocytopenia determined by an automated counter may represent a benign, incidental finding in an asymptomatic patient or a potentially life-threatening disorder. Even if the low platelet count actually is a benign condition itself, in some conditions, any delay resulting from this condition consequently may be seriously hazardous. Low platelet count may alter the decision of heparin administration, which is an essential part of management during acute coronary syndromes. EDTA-dependent pseudothrombocytopenia (PTCP) is reported to have a prevalence of 0.1% in a general hospital; however, it is also reported that around 15% of the patients referred for a specialized center for isolated thrombocytopenia are actually cases of PTCP. In this report, we describe a patient with PTCP who could not receive reperfusion therapy during acute myocardial infarction because of the low platelet counts reported by an automated counter.

Mean platelet volume is elevated during paroxysmal atrial fibrillation: a marker of increased platelet activation?

Paroxysmal atrial fibrillation might be a risk factor for stroke such as chronic atrial fibrillation. We examined the relation between mean platelet volume and paroxysmal atrial fibrillation to determine the effect of paroxysmal atrial fibrillation on the thrombotic state via elevated mean platelet volume. Mean platelet volume is a marker of platelet size, function, and activation. Increased mean platelet volume reflects active and large platelets that release more thromboxane A2 than smaller ones. We hypothesized that mean platelet volume is elevated in patients with paroxysmal atrial fibrillation. The study population comprised 103 consecutive patients who were detected to have paroxysmal atrial fibrillation by 24-h Holter monitoring and 87 control individuals with normal Holter monitoring. Mean platelet volume and inflammatory parameters were measured. Comprehensive clinical and echocardiographic data were collected. Patients with aortic and mitral stenosis, hyperthyroidism, hypothyroidism, malignancy, infection, and pregnancy were excluded from the study. Mean age of the patients was 63 +/- 11 vs. 45 +/- 14 years (P < 0.001) in paroxysmal atrial fibrillation and control groups, respectively. Fifty-seven patients (55%) in paroxysmal atrial fibrillation and 19 (21%) (P < 0.001) patients in control group were men. Mean platelet volume was significantly higher in the paroxysmal atrial fibrillation group when compared with control group (10.0 +/- 2.0 vs. 8.3 +/- 1.5 fl, respectively; P < 0.001). C-reactive protein (18.5 +/- 28 vs. 3.8 +/- 2 mg/l, respectively; P = 0.004) and erythrocyte sedimentation rate (21 +/- 21 vs. 12 +/- 7 mm/h, respectively; P = 0.01) were also higher in the paroxysmal atrial fibrillation group. There was no difference in white blood cell and platelet counts between groups. In a multivariate analysis, elevated mean platelet volume was associated with the occurrence of paroxysmal atrial fibrillation before and after adjustment for age and sex. Our results indicate that inflammatory markers such as C-reactive protein and erythrocyte sedimentation rate and the marker of platelet size and activity mean platelet volume are elevated in patients with paroxysmal atrial fibrillation.

Short- and long-term effect of simvastatin therapy on the heterogeneity of cardiac repolarization in diabetic patients.

The interlead variability of QT interval in the 12-lead electrocardiogram, QT dispersion (QTd), has been shown to reflect dispersion of ventricular refractoriness and may provide a measure of arrhythmogenic potential in diabetic patients. QTd and heart rate corrected QTd (QTcd) were also proposed to be accurate predictors of cardiac death in patients with diabetes. In recent years, experimental and clinical evidence demonstrates that statins exert antiarrhythmic properties. Therefore, in the present study, we have examined whether simvastatin treatment has any effect on the QTd and QTcd in patients with diabetes mellitus. Sixty type 2 diabetic patients without known coronary artery disease and low-density lipoprotein cholesterol >100mg/dl and 30 age and sex-matched non-diabetic controls were included in a prospective study. Out of 60 diabetic patients, 30 were treated with simvastatin 40 mg/day for 1 year and the remaining 30 subjects were served as diabetic controls. No lipid lowering therapy was administered to the diabetic and the non-diabetic controls. QTd and QTcd of treated diabetics and the non-diabetic controls were measured at baseline, 6, 12 weeks and at 1 year. QTd and QTcd of the diabetic controls were obtained at baseline, 6 and 12 weeks. Both QTd and QTcd were significantly greater in patients with the diabetes than in the non-diabetic controls at baseline (52+/-13 ms vs. 41+/-12 ms, p<0.001 and 62+/-17 ms vs. 42+/-11 ms, p<0.001, respectively). Simvastatin therapy significantly decreased both QTd and QTcd at the end of first year compared to baseline (51+/-15 ms vs. 33+/-11 ms, p<0.001 and 60+/-18 ms vs. 38+/-12 ms, p<0.001, respectively). No significant change were found in QTd and QTcd in the non-diabetic (p=0.29 and p=0.87 by ANOVA, respectively) and in the diabetic controls (p=0.72 and p=0.57, by ANOVA, respectively). This study suggests for the first time that simvastatin treatment in diabetic patients with hyperlipidemia is associated with an improvement in the heterogeneity of cardiac repolarization. This may be one of the mechanisms for the reduction in clinical events reported in the survival studies with statins. Further prospective randomized studies are warranted to confirm our findings.

Coronary collateral circulation: any effect on P-wave dispersion?

Coronary collateral circulation determines the severity of ischemic myocardial damage. Increased P-wave dispersion is an independent predictor for atrial fibrillation. Consistent evidence is little about the relation between coronary collateral circulation and arrhythmia risk. In this article, the effect of coronary collateral circulation on P-wave dispersion was evaluated. Collateral grade and P-wave dispersion were ascertained in 100 patients with >or=85% diameter stenoses in left anterior descending or right coronary arteries. Left ventricular function score was also determined in all patients. Coronary collateral circulation was absent in 32 patients, whereas 68 patients had coronary collateral circulation. Patients with collateral grade >or=1 had greater left ventricular function score than did patients with collateral grade 0 (P = .048). However, there was no significant difference between P-wave dispersion of patients with and without coronary collateral circulation (P = .45). The presence of coronary collateral circulation failed to exert a beneficial decreasing effect on P-wave dispersion.

Altered autonomic neural control of the cardiovascular system in patients with polycystic ovary syndrome.

PURPOSE: Polycystic ovary syndrome (PCOS) is frequently accompanied by the presence of cardiovascular risk factors. It has also been recognized that there is a significant relationship between the autonomic nervous system and adverse cardiac events. Heart rate recovery (HRR) after exercise is a marker of parasympathetic activity and attenuation of this parameter has been shown to be associated with increased cardiac mortality. A delayed recovery of systolic blood pressure (SBP) after peak exercise has been found to have diagnostic value and might reflect sympathetic hyperactivity. The analysis of variations in heart rate has also been used to determine the balance between sympathetic and vagal nerve activities in the heart. Our objective was to determine HRR, the SBP response to exercise and heart rate variability (HRV) in patients with PCOS. METHODS: The study population consisted of 26 untreated patients with PCOS and 24 healthy controls who were matched with respect to age, body mass index and physical activity. All subjects underwent symptom-limited exercise tolerance test according to a modified Bruce protocol. Following peak exercise, subjects walked a 2-min cool-down period. Heart rate recovery was calculated as the difference between heart rate at peak exercise and heart rate at the relevant minute of recovery. Blood pressure recovery indexes were determined by dividing the systolic blood pressure at 1, 2 and 3 min in recovery to the systolic blood pressure at peak exercise. RESULTS: HRR at 1 min (HRR1) of the patients with PCOS were significantly lower than that of controls (20+/-4 vs 28+/-8 bpm, p<0.0001). Although, resting SBP of the two groups were similar (117+/-7 vs 117+/-10 mmHg, p=0.663), the SBP of the patients with PCOS at peak exercise were significantly higher when compared to controls (172+/-12 vs 156+/-14 mmHg, p<0.0001). In addition, the SBP of the patients with PCOS remained significantly elevated when compared to controls at the first, second and third minute of recovery (168+/-13 vs 148+/-15 mmHg, 162+/-13 vs 136+/-16 mmHg, 152+/-17 vs 127+/-15 mmHg, respectively, p<0.0001 for all three). The SBP recovery index at 2 and 3 min of the patients with PCOS were significantly higher than that of controls (0.93+/-0.04 vs 0.87+/-0.07, p<0.0001 and 0.87+/-0.07 vs 0.82+/-0.09, p=0.017, respectively). Both time domain and frequency domain parameters of patients with PCOS were significantly lower than that of controls. CONCLUSION: This study shows that the patients with PCOS have attenuated HRR1, exaggerated SBP response to exercise which is delayed to recover and a depressed HRV. These findings might also suggest alterations in autonomic neurol control of the cardiovascular system in this disorder.

Echocardiographic features of patients with paroxysmal atrial fibrillation.

BACKGROUND: There are several risk factors for the initiation of paroxysmal atrial fibrillation (PAF) and the underlying mechanisms are multifactorial. Our study aims to explore the echocardiographic parameters that can identify in patients with PAF compared to normal subjects. METHODS: Eighty consecutive patients who were with PAF detected by 24-h Holter monitoring (HM) were assigned in our study. The control group (n = 80) consisted individuals with no PAF on HM. Indication for HM was palpitations at rest. All patients underwent routine echocardiographic evaluation. Patients with aortic and mitral stenosis, hyperthyroidism, and hypothyroidism were excluded from the study. Comprehensive clinical data were collected. RESULTS: Mean age of the patients with PAF was 63 +/- 11 years and of those 42% were male subjects. There was no difference in the prevalence of hypertension in both groups. Mean left ventricular ejection fraction (LVEF) was 57 +/- 15% in PAF group and 64 +/- 2% in control subjects (p < 0.001). Mean values of left atrial (LA) diameter for PAF and control groups were 3.7 +/- 0.6 cm vs. 3.1 +/- 0.4 cm (p < 0.001), respectively. Patients with PAF had more severe valve insufficiency, higher values of mean pulmonary artery systolic pressures (PAP) (29 +/- 10 mmHg vs. 25 +/- 2 mmHg, respectively; p = 0.001) and deteriorated MV inflow velocities (E:A ratio 0.9 +/- 0.4 vs. 1.1 +/- 0.3, respectively; p = 0.008) when compared to control group. In multivariate logistic regression analysis, LA diameter predicted the development of PAF after adjusted for age and gender. CONCLUSION: Our results indicate that LA diameter predicts the development of PAF.

Rheumatic mitral valve stenosis is associated with impaired flow-mediated dilatation.

It has been demonstrated that rheumatic mitral valve stenosis (RMVS) is associated with an increase in markers of endothelial dysfunction. It is not known whether this association indicates an impairment of flow-mediated dilatation (FMD) of the vascular endothelium. Thirty patients with RMVS and 30 healthy subjects were studied. FMD in patients with RMVS was significantly smaller than in healthy controls (11.9+/-0.4% vs 15.4+/-0.70%, p=0.003). The absolute change in brachial artery diameter in patients with RMVS was also significantly smaller than in healthy subjects (0.42+/-0.26 mm vs 0.64+/-0.32 mm, p<0.001). These findings suggest that vascular endothelial function is altered in patients with RMVS.

Comparison of different regression analyses for identifying risk factors in obese and nonobese patients with coronary artery disease.

This study was designed to assess conventional and novel risk factors in obese and nonobese patients with coronary artery disease (CAD) by using multivariate forward and univariate logistic regression analysis and to find the best model of analysis for identifying these risk factors. The study group consisted of 398 patients who consecutively underwent coronary angiography for the investigation of chest pain, except overweight patients. In univariate logistic regression analysis, high C-reactive protein and cigarette smoking were found to be the strongest variables in obese and nonobese patients with CAD, respectively. In multivariate forward logistic regression analysis, some risk factors were not found as predictors of CAD. Multivariate forward logistic regression analysis with the advantage of a high predictable ratio may be more useful for the analysis of risk factors in patients with CAD.

Intima-media thickness in patients with rheumatic mitral stenosis.

The aim of the study was to determine carotid artery intima-media thickness (IMT) in patients with rheumatic mitral stenosis (RMS). Between January 2001 and December 2003, 112 consecutive patients who had been diagnosed with RMS were screened. Patients with known cerebrovascular disease, coronary artery disease, diabetes, hypertension, left ventricular hypertrophy, hyperlipidemia, abnormal laboratory results, smoking, or age over 50 years were excluded. Forty-eight patients (43 women, 5 men, mean age 39.7 +/-8.3 years) with RMS without risk factors were enrolled in the study. Age- and sex-matched healthy individuals (n = 48; 43 women, 5 men, mean age 39.6 +/-8.6 years) with normal echocardiographic findings constituted the control group. Carotid IMT was determined by using a high-resolution ultrasound system equipped with a 7-MHz imaging probe (Acuson 128 XP CI) with a computer measurement software. The mean common carotid artery IMT thicknesses both in the right (0.604 +/-0.112 mm vs 0.521 +/-0.072 mm) and in the left side (0.581 +/-0.097 mm vs 0.516 +/-0.065 mm) were significantly higher in patients with RMS than in the control group (p < 0.001). Backward stepwise logistic regression analysis identified RMS as independent predictors of increased IMT (OR, 17.25 (CI, 3.99 to 76.28), p <0.001). The present study demonstrated that RMS is associated with increased IMT. The findings indicate that in patients with RMS not only valvular but also systemic endothelium is damaged.

Value of preoperative echocardiography in the prediction of postoperative atrial fibrillation following isolated coronary artery bypass grafting.

The value of echocardiography, especially tissue Doppler imaging (TDI), in the assessment of risk of postoperative atrial fibrillation (AF) after coronary artery bypass grafting (CABG) is not clear. One hundred two consecutive patients (80 men; mean age 61 +/- 10 years) who underwent elective isolated CABG were included in the study. All patients underwent conventional transthoracic echocardiography and TDI of the left and right heart before surgery. Also, 24-hour Holter recordings were obtained for all patients. The study end point was the development of postoperative AF. The surgical mortality rate was 2%. Postoperative AF occurred in 18 patients (18%). Patients with postoperative AF have been significantly older than patients without postoperative AF (73 +/- 7 vs 58 +/- 9 years, respectively; p <0.001). Compared with patients without postoperative AF, a significantly higher proportion of patients with postoperative AF experienced paroxysmal AF before surgery (6% vs 33%, respectively; p = 0.001). Patients with postoperative AF had a significantly larger mean left atrial diameter compared with patients without postoperative AF (37 +/- 3 vs 35 +/- 3 mm, respectively; p = 0.012). Multivariate logistic regression analysis identified age as the most significant predictor of postoperative AF (odds ratio 1.254, 95% confidence interval 1.127 to 1.396; p <0.001). Of the echocardiographic variables, only left atrial diameter was identified as a significant predictor of postoperative AF (odds ratio 1.250, 95% confidence interval 1.055 to 1.562; p = 0.047). In conclusion, in the prediction of postoperative AF after isolated CABG, preoperative transthoracic echocardiography, including both conventional echocardiography and TDI, is of little value.

Assessing coronary blood flow with TIMI frame count method in isolated myocardial bridging.

Myocardial bridging (MB) is a congenital anomaly of coronary arteries and its functional significance remains controversial. Using the TIMI frame count (TFC) method, the authors investigated whether the coronary blood flow velocity is decreased in MB. The study included 18 patients (group 1; 12 men and 6 women; mean age 50 +/-6 years) who had angiographically proven MB and otherwise normal coronary arteries and 20 subjects (group 2; 13 men and 7 women; mean age 50 +/-7 years) with normal-appearing coronary arteriograms. TFC of each group was determined and correlation between TFC and various factors including percent systolic narrowing, age, gender, body mass index, blood pressure, and echocardiographic parameters (ejection fraction, left-right ventricle wall thickness, and diameters) was investigated. Baseline characteristics were similar in the groups. All of the MB was localized to the left anterior descending (LAD) artery. Corrected TFC(LAD) frame count (CTFC) was significantly higher in group 1 than in group 2 (24.7 +/-2.1 vs 22.1 +/-1.9 frames/s, p = 0.001). Circumflex and right coronary artery frames counts were similar in the groups (22.4 +/-2.4 vs 21.3 +/-2.3 frames/s, p = 0.18, 23.1 +/-2.2 vs 23.4 +/-2.1 frames/s, p = 0.7) On correlation analysis, there was no correlation between TFC and the factors investigated. CTFC of patients with MB was higher than of those with normal coronary arteries, irrespective of the degree of systolic narrowing. This may suggest that coronary blood flow is decreased in patients with MB compared to patients having normal coronary arteries.

Effect of slow coronary flow on electrocardiographic parameters reflecting ventricular heterogeneity.

QT interval dispersion reflects regional variations in ventricular repolarization and cardiac electrical instability. Previous studies have showed that QT interval dispersion changes during episodes of myocardial ischemia. Slow coronary flow (SCF) in epicardial coronary arteries is a rare and unique angiographic finding. Whether this pattern of flow is associated with electrocardiographic abnormalities is unknown. Therefore, this study was designed to investigate whether SCF results in electrocardiographic (ECG) changes compared to normal coronary flow. For this aim 24 patients with angiographically proven SCF who had no obstructive coronary lesion (group I) and 25 patients without coronary artery disease (group II) were included in the study. Both groups underwent a routine standard 12-lead surface electrocardiogram recorded at 50 mm/s during rest. QT dispersion (QTd), corrected QT (QTc), and corrected QT dispersion (QTcd) were calculated. Distributions of sex, age, body mass index (BMI), and cardiac risk factors were similar in the 2 groups. Mean heart rate was similar in the 2 groups (74 +/-8 vs 77 +/- 7 p > 0.05). Mean QRS interval durations were similar in the groups (92 +/-7 vs 90 +/-6 ms p > 0.005). In group I, QTd, QTcd, and QTc, were significantly higher than in group II (QTd: 73 +/-14 vs 40 +/-14; QTcd: 71 +/-15 vs 42 +/-9; QTc: 414 +/-14 vs 388 +/-13, respectively p <0.05). In conclusion, SCF was found to be associated with prolonged QT interval and increased QT dispersion. Ischemia in microvascular level and/or altered autonomic regulation of the heart may be responsible mechanisms.