Taner Ulus

Fractal scaling of laser Doppler flowmetry time series in patients with essential hypertension

The full diagnostic potential of the fractal complexity measure, α, of detrended fluctuation analysis (DFA) has not been realized yet. To reveal the impaired mechanisms in the blood flow regulation in patients with essential hypertension (EHT), we studied the laser Doppler flowmetry (LDF) time series by applying DFA. Forearm microvascular blood flow was measured by LDF during supine rest. After a 15 min baseline recording, microvascular response to thermal hyperemia was measured over 30 min. We found three distinct scaling regions; corresponding to the integration of local mechanisms, cardiac effect on local blood flow, and the coupling of extrinsic factors (cardiac and respiratory) to local blood flow by myogenic mechanism. In the control group, local scaling exponent, α(L)=0.96 ± 0.08, did not change but cardiac scaling exponent, α(C)=1.53 ± 0.05, for baseline signal was increased to α(CT)=1.73 ± 0.10 and cardio-respiratory scaling exponent, α(CR)=0.73 ± 0.19, was decreased to α(CRT)=0.24 ± 0.06 during vasodilatation in response to local heating. However, we found significantly different scaling exponents, α(LT)<1, α(CT) ≥ α(C)<1.5 and α(CR) ≈ α(CRT)>0.5 in patients with EHT. Our findings suggest that the local regulatory and the cushioning peripheral vascular functions are impaired in patients with EHT, and vascular/microvascular pathology can be evaluated by applying DFA to LDF signal.

The onset mechanisms of ventricular tachycardia.

Clinical and electrophysiological features of different initiation patterns of ventricular tachycardia (VT) have been widely studied. At least two different onset patterns of VT have been defined in the studies. Tachycardias, which are preceded by either a single or multiple ventricular ectopic activity, including a short-long-short sequence, are defined as nonsudden onset and those, which are not preceded by ventricular ectopy are defined as sudden onset. The knowledge of initiation pattern of VTs may have some clinical importance and can be essential for the selection of treatment strategies. The use of Holter electrocardiograms and analysis of intracardiac electrograms from implantable cardioverter-defibrillators enables to evaluate the initiation patterns of VTs.

Monocyte to High-Density Lipoprotein Ratio Predicts Contrast-Induced Nephropathy in Patients With Acute Coronary Syndrome

Contrast-induced nephropathy (CIN) is associated with worse prognosis in patients with acute coronary syndrome (ACS). Early identification and intervention for patients with a high risk of CIN are very important to improve clinical outcomes. Inflammation plays important role in the development of CIN in the setting of ACS. The monocyte to high-density lipoprotein ratio (MHR) is a novel inflammatory marker. Bleeding is also associated with worse prognosis in such patients. We aimed to investigate whether the preprocedural MHR had a predictive role for CIN development in such patients. In addition, using the thrombolysis in myocardial infarction classification, we aimed to assess whether there was any relationship between bleeding and CIN. A total of 647 patients (496 males; age: 63.3 ± 12.7 years) with ACS who underwent percutaneous coronary intervention (PCI) were included in the study. Seventy patients (10.8%) had developed CIN. Age, diabetes mellitus, contrast volume, estimated glomerular filtration rate, and MHR were independent predictors for CIN. Preprocedural MHR may be used as a simple marker of CIN. It may help with the early identification of patients with ACS who underwent PCI who are at high risk of CIN thus allowing the planning of protective measures.

The CYP2C19*2 and CYP2C19*17 Polymorphisms play a Vital Role in Clopidogrel Responsiveness after Percutaneous Coronary Intervention: A Pharmacogenomics Study

Clopidogrel inhibits platelet activation and aggregation by blocking the P2Y12 receptor. Dual antiplatelet therapy with clopidogrel and aspirin is recommended treatment by current guidelines for patients undergoing percutaneous interventions. Recurrent ischaemic cardiac events after this treatment showed lack of clopidogrel responsiveness. We aimed to investigate the most noticeable variants in the genes involved in clopidogrel pharmacokinetics and pharmacodynamics. A total of 347 Turkish patients who underwent percutaneous coronary interventions with stent implantation were included in our study. Platelet reactivity (PRU) and % inhibition were measured with VerifyNow P2Y12 assay in blood samples collected from patients who took a standard dose of clopidogrel (75 mg/day) for at least 7 days. The variants in the CYP2C19, CYP3A4, CYP2B6, ABCB1, ITGB3 and PON1 genes were genotyped using the Sequenom MassARRAY system. When grouped, the patients with PRU values >208 as non‐responsiveness to clopidogrel therapy; 104 (30%) patients were non‐responders and 243 (70%) patients were responders. A significant association was found between the CYP2C19*2 (G636A) polymorphism and non‐responsiveness to clopidogrel therapy (p < 0.001). An allele frequency of this single nucleotide polymorphism was high in non‐responders; its odds ratio was 2.92 compared with G allele (p < 0.001). PRU values of CT genotypes were lower (p = 0.029) and % inhibition values of CT genotypes were higher (p = 0.008) compared with CC genotypes for the CYP2C19*17 (C806T) polymorphism. None of the other genetic variants were found to be statistically associated with non‐responsiveness to clopidogrel and antiplatelet activity. Our findings suggest that the CYP2C19*2 polymorphism is associated with non‐responsiveness to clopidogrel therapy and the CYP2C19*17 polymorphism enhances antiplatelet activity of clopidogrel. Depending on haplotypes of these two polymorphisms, clopidogrel‐treated patients can be protected or not from stent thrombosis and ischaemic events.

Protection Against Contrast-Induced Nephropathy in Patients With Acute Coronary Syndrome Undergoing Percutaneous Coronary Intervention

We thank Karanfil et al for their comments about our paper entitled “Monocyte to High-Density Lipoprotein Ratio Predicts Contrast-Induced Nephropathy in Patients With Acute Coronary Syndrome.” In our study, after contrast medium exposure, physiologic (0.9%) saline was given intravenously (IV) at a rate of 1 mL/ kg/h for 12 hours. If angiography was performed after 12 hours of admission, physiologic saline was also administered for 12 hours before the procedure. In patients with known left ventricle (LV) systolic dysfunction (LV ejection fraction <40%) or overt heart failure, the hydration rate was reduced to 0.5 mL/kg/h. In addition, 1.3% sodium bicarbonate (154 mEq/L) was given IV at a rate of 3 mL/kg over 60 minutes before angiography and 1 mL/kg/h during and for 6 hours after angiography. On the day of angiography and 1 day after angiography, oral 2 1200 mg dose of N-acetylcysteine was administered. We did not use theophylline.

Asystole induced by radiofrequency catheter ablation of slow pathway

Radiofrequency (RF) catheter ablation is a treatment of choice widely used for a variety of supraventricular tachycardia. Transient sinus and atrioventricular (AV) node dysfunctions may occur during RF application to sites remote from the sinus and AV nodes, but they generally resolve quickly after cessation of RF current. We present a case of two episodes of asystole in a 43-year-old man induced by RF catheter ablation of an AV nodal slow pathway. A Bezold-Jarisch-like reflex, direct stimulation of parasympathetic fibers traveling to the sinus and AV nodes, RF-induced myocardial injury or pain could be responsible for this situation.

Early hyperbaric oxygen therapy for cerebral air embolism during atrial fibrillation ablation

Cerebral air embolism is a potentially life‐threatening complication of left‐sided ablation procedures. We present a 51‐year‐old woman with cerebral air embolism during atrial fibrillation cryoballoon ablation. Taking a deep breath while removing the dilatator was the most likely mechanism in our case. The patient was successfully treated with hyperbaric oxygen therapy at early stage and was discharged without any neurological sequelae.

Predictors of new-onset atrial fibrillation in elderly patients with acute coronary syndrome undergoing percutaneous coronary intervention

BackgroundThe development of atrial fibrillation (AF) during the course of acute coronary syndrome (ACS) is related to poor prognosis. Possible predictors of new-onset AF (NOAF) have not been adequately investigated in elderly patients with ACS undergoing percutaneous coronary intervention (PCI). We aimed to identify the factors associated with NOAF in such patients.MethodsA total of 308 elderly patients with ACS undergoing PCI were enrolled in the study. Patients were divided into two groups: without NOAF [254 patients, 64.6% men, age: 73.5 (69.0–79.0) years] and with NOAF [54 patients, 70.4% men, age: 75.0 (68.7–81.2) years]. Clinical, angiographic, and laboratory features including neutrophil-to-lymphocyte ratio (NLR) and monocyte-to-high-density lipoprotein ratio (MHR) were compared between the groups.ResultsThe percentages of prior myocardial infarction (MI) (20.4 vs. 5.9%) and Killip III/ IV (24.1 vs. 7.1%), NLR [4.5 (2.6–7.2) vs. 3.2 (2.0–6.0)], and MHR [19.4 (15.7–26.5) vs. 12.9 (9.9–18.5)] were higher in patients with NOAF compared to the others (p = 0.020, < 0.001, 0.030, and < 0.001, respectively). In multivariate regression analysis, prior MI (OR 4.509, 95% CI 1.679–12.106, p = 0.003) and MHR (OR 1.102, 95% CI 1.054–1.152, p < 0.001) independently predicted NOAF. In addition, Killip III/IV was found to be an independent predictor of 6-month overall mortality (HR 2.949, 95% CI 1.218–7.136, p = 0.016).ConclusionsPrior MI and MHR are independent predictors of NOAF in elderly patients with ACS undergoing PCI. Killip III/IV predicts 6-month overall mortality in such patients.

Electrocardiographic estimation of successful ablation site in patients with manifest inferior paraseptal accessory pathway

Inferior paraseptal accessory pathways (APs) have a wide distribution and prediction of AP location before radiofrequency ablation is very important in such pathways. We aimed to estimate successful ablation site based on electrocardiogram in 137 patients (mean age: 25.8±9.0; 126 males) with single manifest inferior paraseptal AP. Right endocardial inferior paraseptal APs were discriminated from left endocardial APs with an R/S ratio <1 (p<0.001) and negative delta wave in lead V1 (p<0.001). Epicardial inferior paraseptal APs were differentiated from endocardial APs by a negative delta wave in lead II (p=0.001), positive delta waves in AVR (p<0.001) and V1 (p=0.012), R/S ratio <1 in lead II (p=0.03), and R/S ratio ≥1 in V1 (p=0.04). Delta wave polarity and R/S ratio in lead V1 differentiate right endocardial inferior paraseptal APs from left endocardial APs. Delta wave polarities in leads II, AVR and V1, and R/S ratios in leads II and V1 estimate epicardial inferior paraseptal APs.