Electrocardiography Predictive Value on Coronary Slow Flow Phenomenon

Coronary Slow Flow Phenomenon (CSFP) is characterized by the slow flow of contrast in one or more epicardial coronary vessels without evidence of coronary artery stenosis during coronary angiography procedures. CSFP is fairly common at the time of elective angiography with an incidence of around 7% and accounts for about 4% of hospitalized unstable angina cases. Coronary angiography is currently still the only effective way to detect CSFP, but this procedure is an invasive procedure with high costs, there is a risk of allergy to contrast. Electrocardiography (ECG), as a widely available, inexpensive, and simple modality is felt to be an attractive alternative in early detection of this abnormality. The ECG parameters on CSFP discussed in this study include; p-wave dispersion, QT interval dispersion, QRS intrinsic (Tpeak-Tenddeflection duration), and QRS fragmentation. Further studies are needed on the ECG image in CSFP so that in the future ECG can be a cheaper and non-invasive diagnostic modality for CSFP compared to coronary angiography.

Safety of low-dose dobutamine stress test in coronary slow flow phenomenon

Purpose: To investigate the feasibility and safety of a low-dose dobutamine stress test in coronary slow flow phenomenon (CSFP) patients.Methods: One hundred and forty-two CSFP patients, and forty-four patients without CSFP or significant epicardial coronary stenosis who served as the control group, were retrospectively reviewed. All patients were infused intravenously with dobutamine at an initial infusion rate of 5 μg/kg/min which was then increased at 8-min intervals to 10, 15, and 20 μg/kg/min. Symptoms and echocardiography were monitored simultaneously.Results: Patient tolerance decreased as the doses of dobutamine increased. No termination of the test occurred without dobutamine or at the infusion rate of 5 μg/kg/min. Nonetheless, when the infusion rates were adjusted to 15 and 20 μg/kg/min, the incident of side effects reached up to 30.9 %, and a few patients experienced ST-segment depression in precordial electrocardiographic leads. There were no induced arrhythmias without dobutamine, while the incidence of arrhythmias was highest at the infusion rate of 20 μg/kg/min. Malignant arrhythmias such as ventricular fibrillation and sustained ventricular tachycardia, were not detected. No significant differences were showed in echocardiogram result for left ventricular ejection fraction (LVEF) between CSFP and control group (63.7±7.9 in the CSFP group, versus 64.3±7.2 in the control group; p = 0.63).Conclusion: A low-dose dobutamine stress test is safe and feasible in CSFP patients.

CORONARY SLOW-FLOW PHENOMENA AND ARRHYTHMIAS

A 50 years old smoker male with arrhythmias and non-obstructive coronaries diagnosed as a case of coronary slow flow phenomenon.

Role of Fibroblast Growth Factor-23 in Coronary Slow Flow Phenomenon Pathogenesis

The phenomenon of angina chest pain without significant epicardial coronary artery stenosis, but accompanied by a slowdown in coronary blood flow is often found in patients with symptoms of acute coronary syndrome who undergoing invasive coronary angiography. This phenomenon of slow coronary blood flow is then called the coronary slow flow phenomenon (CSFP). The pathogenesis mechanism of CSFP remains unclear. The pathogenesis of CSFP is thought to be multifactorial. Endothelial dysfunction, small vessel disease, inflammation, renin system angiotensin aldosterone, atherosclerosis are thought to be involved in the pathogenesis of CSFP. Cardiovascular disease incidence and death were associated with elevated levels of Fibroblast growth factor-23 (FGF-23). High levels of FGF-23 can lead to formation of blood vessel calcification, left ventricular hypertrophy, arterial stiffness, endothelial dysfunction, increased inflammatory markers and elevated levels of angiotensin II. It is suspected that FGF-23 has a role in this event other than as a regulator of bone and mineral metabolism. This literature review aims to determine the relationship between fibroblast growth factor-23 and the pathophysiology of CSFP. Based on the broad role of FGF-23, it is possible that FGF-23 is involved in the pathogenesis of CSFP.

The relationship between triglyceride/high-density lipoprotein cholesterol ratio and coronary slow-flow phenomenon

Purpose: In this study, we aimed to investigate the relationship between high triglyceride (TG)/high-density lipoprotein cholesterol (HDL-C) ratio and coronary slow-flow phenomenon (CSFP) in patients undergoing elective coronary angiography for suspected coronary artery disease. Methods: This prospective study included a total of 84 CSFP patients and 83 controls with normal coronary flow, as evidenced by coronary angiography. The Thrombolysis in Myocardial Infarction (TIMI) frame count (TFC) was used to measure the coronary blood flow velocity. The lipid profiles were analyzed and TG/HDL-C ratio were calculated dividing absolute TG levels by absolute HDL-C levels in peripheral blood. Results: The median TG/HDL-C ratio was higher in the CSFP group than the control group (3.4 [2.6 to 4.9] vs. 2.3 [1.8 to 3], respectively; p<0.001). The multivariate logistic regression analysis revealed that TG/HDL-C ratio was an independent predictor of CSFP (odds ratio [OR]: 1.78, 95% confidence interval [CI]: 1.59-2.32; p=0.001) and TG/HDL-C ratio was positively correlated with the TFC in the CSFP group ( r =0.311, p<0.001). The area under the receiver operating characteristic curve of TG/HDL-C for the diagnosis of CSFP was 0.73 (95% CI: 0.65-0.81; p<0.001). If a cut-off value of 2.75 was used, higher levels of TG/HDL-C ratio could predict the presence of CSFP with 72% sensitivity and 71% specificity. Conclusion: Our study results suggest that TG/HDL-C ratio is associated with CSFP and may be a useful biomarker for predicting CSFP and its severity.