Incidence, electrophysiological characteristics, and long-term follow-up of perimitral atrial flutter in patients with previously confirmed mitral isthmus block.

INTRODUCTION: After mitral isthmus (ΜΙ) catheter ablation, perimitral atrial flutter (PMF) circuits can be maintained due to the preservation of residual myocardial connections, even if conventional pacing criteria for complete MI block are apparently met (MI pseudo-block). We aimed to study the incidence, the electrophysiological characteristics, and the long-term outcome of these patients. METHODS: Seventy-two consecutive patients (mean age 62.4 ± 10.2, 62.5% male) underwent MI ablation, either as part of an atrial fibrillation (AF) ablation strategy (n = 35), or to treat clinical reentrant atrial tachycardia (AT) (n = 32), or to treat AT that occurred during ablation for AF (n = 5). Ιn all patients, the electrophysiological characteristics of PMF circuits were studied by high-density mapping. RESULTS: Mitral isthmus block was successfully achieved in 69/72 patients (95.6%). Five patients developed PMF after confirming MI block. In these patients, high-density mapping during the PMF showed a breakthrough in MI with extremely low impulse conduction velocity (CV). In contrast, in usual PMF circuits that occurred after AF ablation, the lowest CV of the reentrant circuit was of significantly higher value (0.07 ± 0.02 m/s vs 0.25 ± 0.07 m/s, respectively; P < .001). Patients presented with clinical AT had better prognosis in maintaining sinus rhythm after MI ablation compared with patients presented with AF. CONCLUSION: Perimitral atrial flutter with MI pseudo-block may be present after MI ablation and has specific electrophysiological features characterized by remarkably slow CV in the MI. Thus, even after MI block is achieved, a more detailed mapping in the boundaries of the ablation line or reinduction attempts may be needed to exclude residual conduction.

Monocyte-platelets aggregates as cellular biomarker of endothelium-dependent coronary vasomotor dysfunction in patients with coronary artery disease.

Monocyte-platelet aggregates (MPA) are increased in patients with acute coronary syndrome. We investigated whether MPA are associated with the presence of functionally significant coronary stenoses or with coronary arterial endothelial dysfunction. One hundred forty five patients undergoing elective coronary angiography were prospectively enrolled. Functional significance of coronary stenosis was assessed by fractional flow reserve (FFR). Thirty randomly selected patients underwent pacing protocol to evaluate Coronary endothelium-dependent vasomotor function (CVF). Whole blood was drawn to evaluate MPA. In patients with FFR ≤ 0.8 (FFRpos, n = 75), MPA did not significantly differ from FFR >0.8 patients (FFRneg, n = 70) (38.1% [25.7-56.6] vs. 34.0% [20.5-49.9], p = 0.08). CVF was similar in FFRpos and FFRneg patients (percent vessel diameter change, %VDC = 7.19 % [6.01-10.9] vs. 8.0 % [0.81-9.80], p = 0.78). Yet, patients with abnormal CVF showed higher MPA as compared to patients with preserved CVF (28.3% [28.8-53.4] vs. 20.5 % [17.0-32.9], p = 0.01). Moreover, MPA was inversely correlated with %VDC (R2 = 0.26, p < 0.01). MPA levels are significantly higher in patients with abnormal coronary vasomotor function regardless of the presence of functionally significant coronary stenosis.

Acute effects of different alcoholic beverages on vascular endothelium, inflammatory markers and thrombosis fibrinolysis system.

BACKGROUND & AIM: Mild alcohol consumption has been associated with decreased cardiovascular risk, although the underlying mechanisms are still unclear. We compared the acute effects of several alcoholic beverages on endothelial function, inflammatory process and thrombosis/fibrinolysis system in young adults. METHODS: In this randomized intervention trial, healthy young individuals with no risk factor for atherosclerosis were randomized into 5 equally sized groups and received an equal amount of alcohol (30 g), as red wine (264 ml), white wine (264 ml), beer (633 ml), whisky (79 ml) or water (250 ml). Forearm blood flow was determined by gauge-strain plethysmography, at baseline, 1 and 4 h after alcohol intake. Levels of interleukin-6 (IL-6), tumor necrosis factor alpha (TNF-alpha), C-reactive protein (CRP), fibrinogen (Fib), plasminogen activator inhibitor (PAI-1), von Willebrand factor (vWF) and tissue plasminogen activator (tPA) were determined at baseline and 4 h after alcohol consumption. RESULTS: Reactive hyperemia was significantly increased 1 h after beer and red wine consumption (p<0.05 for both), while it returned at baseline at 4 h (p=ns vs baseline) but remained unchanged in all the other groups. vWF was decreased in the beer and red wine groups (p<0.05 for both) only. PAI-1/tPA ratio remained unchanged only in red wine and control group. Inflammatory markers remained unchanged in all the groups. CONCLUSIONS: Acute consumption of red wine or beer improves endothelial function and decreases vWF levels, suggesting that the type of beverage may differently affect endothelial function and thrombosis/fibrinolysis system in healthy adults.

Effects of lipid profile on forearm hyperemic response in young subjects.

INTRODUCTION: The role of lipids in atherogenesis is now well established. However, the exact mechanisms by which different lipoproteins affect endothelial function and induce atherogenesis are still not well understood. In the present study we examined the effect of lipid profile on forearm vasodilatory response to reactive hyperemia, an index of endothelial function, in a cohort of young, low-risk adults. METHODS: One hundred sixty seven healthy subjects were included in the study. The effect of total cholesterol, high density lipoprotein (HDL), low density lipoprotein (LDL), triglycerides, apolipoprotein (apo)-A1, apo-B and apo-E on endothelial function and inflammatory process was examined. Endothelial function was evaluated by determining forearm vasodilatory response to reactive hyperemia (RH%) using gauge-strain plethysmography. RH% was defined as the % change of forearm blood flow from baseline to the maximum flow during post-ischemic hyperemia. Endothelium independent dilatation in response to nitroglycerin (NTG%) was defined as the % change of forearm blood flow from baseline to the maximum flow after sublingual nitroglycerin administration. RESULTS: RH% was correlated with HDL (r = 0.267, p = 0.001), LDL (r = 0.355, p = 0.0001), triglycerides (rho = -0.366, p = 0.0001), apo-Al (r = 0.240, p = 0.004) and apo-B (r = -0.277, p = 0.005). NTG% was not affected by serum lipid levels. In multivariate linear regression, LDL (beta = -0.217 [SE: 0.098], p = 0.028), apo-A1 (beta = 0.277 [SE: 0.124], p = 0.027) and age (beta = 0.916 [SE:0.369], p = 0.015) were independent predictors for RH% in this population (R2 for the model: 0.243, p = 0.0001). CONCLUSIONS: Elevated lipid levels decrease forearm vasodilatory response to reactive hyperemia. Apolipoproteins, and especially apo-Al, are important determinants of endothelial function in these subjects, independently of LDL, HDL and triglycerides, implying that full measurement of the lipid profile may be of great importance in risk stratification of young individuals.

Combined effects of smoking and hypercholesterolemia on inflammatory process, thrombosis/fibrinolysis system, and forearm hyperemic response.

The combined effects of smoking and hypercholesterolemia on the inflammatory process, the thrombosis/fibrinolysis system, and forearm hyperemic response were investigated. It was shown that smokers with hypercholesterolemia (n = 25) had a reduced and delayed forearm hyperemic response compared with healthy smokers (n = 24), patients with hypercholesterolemia (n = 26), and healthy controls (n = 75; p <0.01 for all). This phenomenon was associated with a respective increase in the inflammatory process and changes in the thrombosis/fibrinolysis system.