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.

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.

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.

Detection of patients with coronary artery disease using cardiac magnetic field mapping at rest

We studied the use of cardiac magnetic field mapping to detect patients with CAD without subjecting them to stress. Fifty-nine healthy control subjects and 101 patients with CAD without previous MI were included. The optimal positions for detecting CAD were located in the left superior parasternal and in the inferior midsternal area. Values for ST slope, ST shift, T peak amplitude, ST-T integral, and magnetic field map orientation differed significantly between the 2 groups. Three parameters together in a multivariate analysis yielded a sensitivity of 84% and a specificity of 83% in distinguishing patients with CAD from control subjects. We suggest that cardiac magnetic field mapping is a promising technique to identify patients with CAD.

Plasma Nitric Oxide Level and Its Role in Slow Coronary Flow Phenomenon

Previous studies have suggested that microvascular abnormalities and endothelial dysfunction cause slow coronary flow (SCF). The objective of this study was to assess the plasma nitric oxide (NO) level and determine its role in the pathogenesis of SCF phenomenon. Thirty-six patients with SCF (group 1) and otherwise patent coronary arteries and 34 subjects with normal coronary flow (group 2) were included in the study. Coronary flow was quantified according to the TIMI Frame Count (TFC) method. Brachial artery endothelium-dependent flow-mediated dilatation (FMD) and nitroglycerin (NTG)-induced endothelium-independent dilatation were studied in both groups. In addition, plasma NO levels were measured and their contribution to FMD was determined. The sex, age, body mass index, arterial blood pressure, and heart rate distributions were similar in both groups. TFC was significantly higher in group 1 compared to group 2 for each artery. The plasma NO level was lower in patients with SCF than in control subjects (18.4 +/- 4.4 versus 25.2 +/- 6.3 micromol/L P = 0.001). FMD was significantly smaller in group 1 than in group 2 (4.0 +/- 3.2% versus 10.6 +/- 5.8%, P = 0.0001). The percent NTG-induced dilatation was similar in the two groups (16.8 +/- 1.1% versus 17.1 +/- 1.1%, P = 0.42). In group 1, the plasma NO level was correlated with percent of FMD. Also, the plasma NO level was inversely correlated with TFC for each artery. Reduced NO bioactivity as well as impaired FMD support the presence of endothelial damage in the pathogenesis of SCF phenomenon.