Predictive value of very low frequency at spectral analysis among patients with unexplained syncope assessed by head-up tilt testing.

BACKGROUND: The role of heart rate variability (HRV) in the prediction of vasovagal syncope during head-up tilt testing (HUTt) is unclear. AIM: To evaluate the ability of the spectral components of HRV at rest to predict vasovagal syncope among patients with unexplained syncope referred for HUTt. METHODS: Twenty-six consecutive patients with unexplained syncope were enrolled in the study. All patients underwent HRV evaluation at rest (very low frequency [VLF], low frequency [LF], high frequency [HF] and LF/HF ratio) and during HUTt. HUTt was performed using the Westminster protocol. Continuous electrocardiogram and blood pressure monitoring were performed throughout the test. RESULTS: Eight (31%) patients developed syncope during HUTt. There were no baseline differences in terms of clinical features and HRV variables among patients who developed syncope and those who did not, except for VLF (2421 vs 896ms2; P<0.001). In the multivariable logistic regression analysis, including age and sex, VLF was the only independent variable associated with syncope during HUTt (odds ratio 1.002, 95% confidence interval 1.0003-1.0032; P=0.02). The area under the curve at rest was 0.889 for VLF, 0.674 for HF and 0.611 for LF. A value of VLF>2048ms2 was the optimal cut-off to predict syncope during HUTt (sensitivity 87.5%, specificity 72.2%). CONCLUSIONS: VLF at rest predicted the incidence of syncope during HUTt. Further studies are warranted to confirm these preliminary data.

Hyperacute Hemodynamic Effects of BiPAP Noninvasive Ventilation in Patients With Acute Heart Failure and Left Ventricular Systolic Dysfunction in Emergency Department.

BACKGROUND: Acute heart failure (AHF) is one of the leading causes of admission to emergency department (ED); severe hypoxemic AHF may be treated with noninvasive ventilation (NIV). Despite the demonstrated clinical efficacy of NIV in relieving symptoms of AHF, less is known about the hyperacute effects of bilevel positive airway pressure (BiPAP) ventilation on hemodynamics of patients admitted to ED for AHF. We therefore aimed to assess the effect of BiPAP ventilation on principal hemodynamic, respiratory, pulse oximetry, and microcirculation indexes in patients admitted to ED for AHF, needing NIV. METHODS: Twenty consecutive patients admitted to ED for AHF and left ventricular systolic dysfunction, needing NIV, were enrolled in the study; all patients were treated with NIV in BiPAP mode. The following parameters were measured at admission to ED (T0, baseline before treatment), 3 hours after admission and initiation of BiPAP NIV (T1), and after 6 hours (T2): arterial blood oxygenation (pH, partial pressure of oxygen in the alveoli/fraction of inspired oxygen ratio, Paco2, lactate concentration, HCO3-), hemodynamics (tricuspid annular plane systolic excursion, transpulmonary gradient, transaortic gradient, inferior vena cava diameter, brain natriuretic peptide [BNP] levels), microcirculation perfusion (end-tidal CO2 [etco2], peripheral venous oxygen saturation [SpvO2]). RESULTS: All evaluated indexes significantly improved over time (analysis of variance, P < .001 in quite all cases.). CONCLUSIONS: The BiPAP NIV may rapidly ameliorate several hemodynamic, arterial blood gas, and microcirculation indexes in patients with AHF and left ventricular systolic dysfunction.

Coronary artery ectasia is related to coronary slow flow and inflammatory activation.

AIM: To evaluate possible links between coronary flow anomalies, inflammatory activation and coronary artery ectasia (CAE). METHODS: Fourteen consecutive patients with CAE diagnosed at coronary angiography were enrolled in the study and compared with 17 patients with coronary atherosclerosis without CAE and 15 controls with normal coronary angiography. All patients underwent blood assay with evaluation of circulating levels of interleukin (IL)-1b, IL-2, IL-8, IL-10 and tumor-necrosis-factor(TNF)-α. The number of coronary segments showing CAE at coronary angiography, the Markis class, and coronary flow assessed with TIMI frame count (TFC) were also assessed. RESULTS: Subjects with CAE showed higher levels of IL-1b, TNF-α, and IL-10 (p<0.05). The number of coronary segments showing CAE was related to TFC both in left anterior descending (LAD) coronary artery (p<0.01) and in right coronary artery (RCA) (p<0.001), and to circulating levels of IL-1b and IL-10 (p<0.01). TFC on LAD (p<0.05) and on RCA (p<0.001), circulating IL-1b levels (p<0.01), IL-8 (p<0.05), and IL-10 (p<0.01) were proportionally increased comparing controls, subjects with coronary atherosclerosis without CAE, and with decreasing Markis class. In subjects with CAE involving LAD, TFC on LAD was related to IL-8 and TNF-α levels (p<0.05); subjects with IL-1b levels above median showed higher TFC values on LAD (p<0.01), CONCLUSIONS: In subjects with CAE, the extension of disease is related to the impairment of coronary circulation and to inflammatory activation. The inflammatory response is also related to an impaired coronary circulation.