A novel method for precise implantation of tracheal Y-shaped stent.

The tracheal Y-shaped stent is mainly used for the treatment of critical patients with airway stenosis or esophagotracheal fistula near carina. A novel method for precise implantation of Y-shaped tracheal stents was developed using double-lumen endotracheal intubation and flexible bronchoscopy. This approach aims to address the limitations associated with X-ray or rigid bronchoscopy guidance, such as operational difficulties and the risk of inaccurate stent placement leading to implantation failure or suffocation. With this new technique, 13 tracheal Y-shaped stents were successfully implanted. This method shows promise in reducing the complexity of stent implantation and facilitating timely treatment for patients in need. Additionally, it has the potential to update current operating standards and guidelines for this procedure.

Dynamic Transcriptome Profiling Reveals LncRNA-Centred Regulatory Networks in the Modulation of Pluripotency.

Long noncoding RNAs (lncRNAs) have emerged as vital regulators of gene expression during embryonic stem cell (ESC) self-renewal and differentiation. Here, we systemically analyzed the differentially regulated lncRNAs during ESC-derived cardiomyocyte (CM) differentiation. We established a perspicuous profile of lncRNA expression at four critical developmental stages and found that the differentially expressed lncRNAs were grouped into six distinct clusters. The cluster with specific expression in ESC enriches the largest number of lncRNAs. Investigation of lncRNA-protein interaction network revealed that they are not only controlled by classic key transcription factors, but also modulated by epigenetic and epitranscriptomic factors including N6-methyladenosine (m6A) effector machineries. A detailed inspection revealed that 28 out of 385 lncRNAs were modified by methylation as well as directly recruited by the nuclear m6A reader protein Ythdc1. Unlike other 27 non-coding transcripts, the ESC-specific lncRNA Gm2379, located in both nucleus and cytoplasm, becomes dramatically upregulated in response to the depletion of m6A or Ythdc1. Consistent with the role of m6A in cell fate regulation, depletion of Gm2379 results in dysregulated expressions of pluripotent genes and crucial genes required for the formation of three germ layers. Collectively, our study provides a foundation for understanding the dynamic regulation of lncRNA transcriptomes during ESC differentiation and identifies the interplay between epitranscriptomic modification and key lncRNAs in the regulation of cell fate decision.

Focal atrial tachycardia: new insight from noncontact mapping and catheter ablation.

BACKGROUND: This study investigated the electrophysiologic characteristics, atrial activation pattern, and effects of radiofrequency (RF) catheter ablation guided by noncontact mapping system in patients with focal atrial tachycardia (AT). METHODS AND RESULTS: In 13 patients with 14 focal ATs, noncontact mapping system was used to map and guide ablation of AT. AT origins were in the crista terminalis (n=8), right atrial (RA) free wall (n=3), Koch triangle (n=1), anterior portion of RA-inferior vena cava junction (n=1), and superior portion of tricuspid annulus (n=1); breakout sites were in the crista terminalis (n=5), RA free wall (n=5), middle cavotricuspid isthmus (n=2), and RA-superior vena cava junction (n=2). ATs arose from the focal origins (11 ATs inside or at the border of low-voltage zone), with preferential conduction, breakout, and spread to the whole atrium. After applications of RF energy on the earliest activation site or the proximal portion of preferential conduction from AT origin, 13 ATs were eliminated without complication. During the follow-up period (8+/-5 months), 11 (91.7%) of the 12 patients with successful ablation were free of focal ATs. CONCLUSIONS: Focal AT originates from a small area and spreads out to the whole atrium through a preferential conduction. Application of RF energy guided by noncontact mapping system was effective and safe in eliminating focal AT.

Catheter ablation of paroxysmal atrial fibrillation initiated by non-pulmonary vein ectopy.

BACKGROUND: Most of the ectopic beats initiating paroxysmal atrial fibrillation (PAF) originate from the pulmonary vein (PV). However, only limited data are available on PAF originating from the non-PV areas. METHODS AND RESULTS: Two hundred forty patients with a total of 358 ectopic foci initiating PAF were included. Sixty-eight (28%) patients had AF initiated by ectopic beats (73 foci, 20%) from the non-PV areas, including the left atrial posterior free wall (28, 38.3%), superior vena cava (27, 37.0%), crista terminalis (10, 3.7%), ligament of Marshall (6, 8.2%), coronary sinus ostium (1, 1.4%), and interatrial septum (1, 1.4%). Catheter ablation eliminated AF with acute success rates of 63%, 96%, 100%, 50%, 100%, and 0% in left atrial posterior free wall, superior vena cava, crista terminalis, ligament of Marshall, coronary sinus ostium, and interatrial septum, respectively. During a follow-up period of 22+/-11 months, 43 patients (63.2%) were free of antiarrhythmic drugs without AF recurrence. CONCLUSIONS: Ectopic beats initiating PAF can originate from the non-PV areas, and catheter ablation of the non-PV ectopy has a moderate efficacy in treatment of PAF.

Noncontact three-dimensional mapping and ablation of upper loop re-entry originating in the right atrium.

OBJECTIVES: This study was aimed at delineating the reentrant circuit of right atrial (RA) upper loop re-entry using noncontact three-dimensional mapping. BACKGROUND: Various forms of atypical atrial flutter including lower loop re-entry and left atrial flutter have been demonstrated. However, little is known about upper loop re-entry in the RA. METHODS: The study population consisted of eight patients (65 +/- 12 years, seven men) with atypical atrial flutter. Right atrial activation during atrial flutter was visualized using a noncontact mapping system (EnSite-3000 with Clarity Software, St. Paul, Minnesota) for a three-dimensional reconstruction of the endocardial depolarization. The narrowest part of the re-entrant circuit was targeted using radiofrequency catheter ablation. RESULTS: Noncontact mapping showed macro-re-entry confined to the RA free wall with RA activation time accounting for 100% of the cycle length (214 +/- 21 ms) in all eight patients. Two patients had counterclockwise activation, and six patients had clockwise activation around the central obstacle, which was composed of the crista terminalis, the area of functional block, and superior vena cava. The lower turn-around points were located at the conduction gap in the crista terminalis. Radiofrequency linear ablation of the conduction gap in the crista terminalis was performed and eliminated atrial flutter in six patients without recurrence during a follow-up of 3.2 +/- 1.1 months. CONCLUSIONS: Atypical atrial flutter could arise from upper loop re-entry in the RA with conduction through the gap in the crista terminalis. Radiofrequency linear ablation of the conduction gap was effective in eliminating this atrial arrhythmia.

Functional characterization of the crista terminalis in patients with atrial flutter: implications for radiofrequency ablation.

OBJECTIVES: The aim of the study was to investigate the conduction properties and anisotropy of the crista terminalis (CT) in patients with atrial flutter (AFL) using non-contact mapping. BACKGROUND: The CT is a posterior barrier during typical AFL. However, the CT has transverse conduction capabilities in patients with upper loop re-entry (ULR). METHODS: Twenty-two patients (16 males, 63 +/- 15 years) with typical AFL and ULR were included. Non-contact mapping of the right atrium during AFL and pacing from coronary sinus (CS) and low anterolateral right atrium (LARA) was performed to evaluate transverse conduction across the CT. During ULR, the longitudinal (CV(L)) and transverse (CV(T)) conduction velocity along and across the CT were measured. The width of the CT conduction gap was evaluated to guide radiofrequency ablation (RFA). RESULTS: No transverse CT gap conduction was found during typical AFL. Transverse CT gap conduction was found in three patients during CS pacing and in three patients during LARA pacing. During ULR, CV(L) was greater than CV(T) (1.28 +/- 0.43 vs. 0.73 +/- 0.30 m/s, p < 0.001). The CV(L)/CV(T) ratio was 1.95 +/- 0.77, which was inversely related to the CT gap width (15.7 +/- 6.8 mm) (p < 0.001). The RFA of the CT gap was successful in 18 patients. Four patients had recurrence of arrhythmias during the follow-up of 11 +/- 3 months. CONCLUSIONS: Most of the CT conduction gaps were functional and only appeared during ULR. The width of the CT gap was inversely related to the anisotropic ratio of the CT. The RFA of the CT gap was effective in eliminating ULR.

Effects of fluvastatin, an HMG-CoA reductase inhibitor, on serum levels of interleukin-18 and matrix metalloproteinase-9 in patients with hypercholesterolemia.

BACKGROUND: Interleukin-18 (IL-18), a novel proinflammatory marker, and matrix metalloproteinase-9 (MMP-9) represent the indices of plaque stability. It is unknown whether hydroxymethylglutaryl coenzyme A (HMG-CoA) reductase inhibitors (statins), which provide anti-inflammatory and endothelium protection effects, have the property of stabilizing plaque in patients with hypercholesterolemia. HYPOTHESIS: The study was designed to investigate the influence of statin therapy in circulating IL-18, MMP-9, and endothelial function. METHODS: We investigated the effects of a 12-week therapy with fluvastatin on IL-18, MMP-9, and endothelial function in patients with hypercholesterolemia. RESULTS: Compared with placebo, fluvastatin significantly improved flow-mediated vasodilatation to hyperemia, a hallmark of endothelial function [from 3.8% (-3.9 approximately 15.2) to 5.9% (-0.3 approximately 13.2), p = 0.001], and attenuated plasma levels of high sensitivity C-reactive protein (hsCRP) [from 1.3 (0.3 approximately 7.7) to 1.1 mg/l (0.2 approximately 3.5), p = 0.018], IL-18 [from 247.6 (145.4 approximately 378.4) to 196.4 pg/dl (90.7 approximately 380.2), p <0.001], total MMP-9 (from 58 +/- 46.3 to 39.4 +/- 22.4 ng/dl, p = 0.023), and MMP-9 activity [from 6.4 (3.6 approximately 27) to 5.6 ng/dl (3.1 approximately 13.7)]. However, no significant correlation was found between the degree of changes in lipid profile and flow-mediated dilatation (FMD) and plasma concentration of IL-18 and MMP-9. CONCLUSIONS: Fluvastatin reduced plasma concentrations of IL-18 and MMP-9, and improved endothelial function in patients with hypercholesterolemia independent of its lipid-lowering effect.

Effect of rosuvastatin on plasma levels of asymmetric dimethylarginine in patients with hypercholesterolemia.

Elevated plasma levels of asymmetric dimethylarginine (ADMA) have been associated with attenuated endothelium-dependent vasodilation in hypercholesterolemic patients. However, whether lowering of plasma cholesterol concentration by hydroxymethylglutaryl coenzyme A reductase inhibitors (statins) can reduce plasma ADMA levels is still not clear. This study was a multicenter, randomized, double-blind, placebo-controlled design including 46 patients with elevated low-density lipoprotein cholesterol levels. Patients were randomized into 2 groups: rosuvastatin 10 mg/day and placebo for 6 weeks. Plasma levels of ADMA, 8-isoprostane (as a marker of oxidative stress), homocysteine, and high-sensitivity C-reactive protein were measured at baseline and 6 weeks later. Endothelial function assessed by flow-mediated vasodilation of the brachial artery was performed in 11 patients in the rosuvastatin group and in 12 in the placebo group. Baseline characteristics of both groups were similar, and the plasma ADMA levels were significantly correlated with 8-isoprostane (r = 0.388, p = 0.008). After 6 weeks of treatment, plasma ADMA levels were significantly reduced in the rosuvastatin group (from 0.60 +/- 0.19 to 0.49 +/- 0.10 micromol/L, p <0.001). Increases in flow-mediated vasodilation were positively correlated with reductions in plasma levels of ADMA (p = 0.017) and low-density lipoprotein cholesterol (p <0.001). Thus, our findings suggest that treatment with rosuvastatin in patients with hypercholesterolemia may lead to a significant reduction in plasma ADMA levels, which appear to be related to the improvement in endothelial function by rosuvastatin.

Double potential interval and transisthmus conduction time for prediction of cavotricuspid isthmus block after ablation of typical atrial flutter.

BACKGROUND: Complete bi-directional isthmus block is the endpoint of typical atrial flutter ablation. The purpose of this study was to investigate the feasibility of the local double potential (DP) interval and the change in transisthmus conduction time for predicting complete isthmus block after ablation of the cavotricuspid isthmus. METHODS: The study population consisted of 32 patients with typical atrial flutter after a procedure of radiofrequency (RF) ablation of the cavotricuspid isthmus (16 had incomplete block and 16 had complete block). The transisthmus conduction time was determined during pacing from the proximal coronary sinus and low lateral right atrium before and after RF ablation. The DP interval close to the ablation line was evaluated after final RF energy application. RESULTS: In the counterclockwise direction, transisthmus conduction time had an increase of 37 +/- 25.4% and 127.3 +/- 35.5% (P < 0.001), and the DP interval was 63.3 +/- 8.7 ms and 120 +/- 17.4 ms (P < 0.001) after achievement of incomplete and complete block, respectively. The sensitivity, specificity, positive and negative predictive values of an increase in the transisthmus conduction time > or =50% were 100%, 81%, 84% and 100%, respectively; those of DP interval > or =100 ms were 100%. In the clockwise direction, transisthmus conduction time had an increase of 38.8 +/- 28.6% and 135.7 +/- 63.6% (P < 0.001), and the DP interval was 63.6 +/- 13.8 ms and 127.7 +/- 27.1 ms (P < 0.001) after achievement of incomplete and complete block, respectively. The sensitivity, specificity, positive and negative predictive values of an increase in the transisthmus conduction time > or =50% were 100%, 67%, 83% and 100%, respectively; those of the DP interval > or =100 ms were 100%. CONCLUSIONS: The transisthmus conduction time > or =50% increase or DP interval > or =100 ms was feasible to predict complete bi-directional isthmus block.

Recurrent atrial flutter and atrial fibrillation after catheter ablation of the cavotricuspid isthmus: a very long-term follow-up of 333 patients.

INTRODUCTION: Radiofrequency catheter ablation of the cavotricuspid isthmus is an effective therapy for typical atrial flutter (AFL), however, the long-term recurrence of AFL and early or late occurrence of atrial fibrillation (AF) are not well defined. This study investigated the long-term (up to 68 months) outcome of patients with typical AFL after catheter ablation of the cavotricuspid isthmus. METHODS: This study included 380 patients with typical AFL, who received linear ablation of the cavotricuspid isthmus. They were followed up at the outpatient clinic. A questionnaire was used to evaluate the symptoms suggestive of tachyarrhythmias, and 12-lead ECG, Holter monitoring and event recorders were used to confirm the diagnosis of tachyarrhythmias. RESULTS: At the end of study, 47 patients lost follow-up, so that 333 patients were enrolled into final analysis. Ten (3%) patients had failed ablation of typical AFL. Univariate analysis showed that left atrial dimension was the only factor related to failed ablation. During the long-term follow-up period of 29 +/- 17 months (range 7 to 68 months), 29 (9%) patients had recurrent AFL, including 15 with typical and 14 with atypical AFL. Univariate and multivariate analyses showed that incomplete isthmus block and inducible atypical AFL were the independent predictors of recurrent typical and atypical AFL, respectively. One hundred and two (31%) patients developed AF, including 48 with early occurrence of AF (within 3 months after ablation), and 54 with late occurrence of AF (greater than 3 months). Univariate and multivariate analyses showed that prior history of AF and inducible AF were independent predictors of early occurrence of AF, and prior history of AF was the only independent predictor of late occurrence of AF. CONCLUSIONS: Linear ablation of the cavotricuspid isthmus is an effective therapy with low recurrence rate for patients with typical AFL. However, one-third patients had early or late occurrence of AF.

Use of fluoroscopic views for detecting Marshall's vein in patients with cardiac arrhythmias.

INTRODUCTION: Recently, several studies showed that focal atrial fibrillation (AF) can be initiated by ectopic beats from the vein of Marshall (VOM). However, the incidence and best fluoroscopic views of VOM have never been reported. METHODS AND RESULTS: 106 patients (Non-AF = 52, AF = 54) underwent balloon-occluded coronary sinus angiography using seven fluoroscopic views (PA, Lateral, RAO 30 degrees, RA 30 degrees + Caudal 20 degrees, LAO 30 degrees, LAO 60 degrees, LAO 60 degrees + Cranial 20 degrees ). The total incidence of VOM was 74.5% (79/106), without significant difference in age (81.1 vs. 71.0%, >65 vs.

Predictors of early and late recurrence of atrial fibrillation after catheter ablation of paroxysmal atrial fibrillation.

INTRODUCTION: The outcome of patients with early recurrence of atrial fibrillation (AF) (within one month) after ablation procedure is controversial. Furthermore, the predictors of early and late (up to mean follow-up 30 months) recurrence of AF are not investigated in depth. AIMS OF THE STUDY: The aim of the present study was to investigate the predictors of early and late recurrence of AF after catheter ablation of arrhythmogenic foci initiating AF in patients with paroxysmal AF. METHODS AND RESULTS: The study included 207 patients (155 men; mean age 62 +/- 13 years) who received catheter ablation of paroxysmal AF. Eighty-one (39%) patients had early recurrence of AF. Five clinical variables were related to the early recurrence of AF: (1) old age (>/=65 years) ( P = 0.004); (2) presence of associated cardiovascular disease ( P = 0.01); (3) presence of multiple AF foci ( P = 0.004); (4) presence of AF foci from left atrial free wall ( P = 0.039); (5) left atrial enlargement ( P = 0.038). Multivariate analysis demonstrated that presence of multiple AF foci could predict early recurrence of AF ( P = 0.013; ratio = 2.24; 95% CI 1.18 to 4.25). During the follow-up period (30 +/- 11 months), 70 (34%) patients had late recurrence of AF, and two clinical variables were related to the late recurrence of AF: (1) presence of early recurrence of AF ( P = 0.025); (2) presence of multiple AF foci ( P = 0.034). Multivariate analysis found that presence of early recurrence of AF could predict late recurrence of AF ( P = 0.046; hazard ratio = 1.62; 95% CI 1.01 to 2.59). Late recurrence of AF happened in 35 (43%) of the 81 patients with early recurrence of AF, and in 35 (28%) of the 126 patients without early recurrence of AF. CONCLUSIONS: Early AF recurrence could predict late AF recurrence.

Asymmetrical dimethylarginine: a novel risk factor for coronary artery disease.

BACKGROUND: Asymmetrical dimethylarginine (ADMA) is an endogenous competitive inhibitor of nitric oxide synthase and has been associated with systemic atherosclerosis; however, the role of ADMA in patients with coronary artery disease (CAD) has not been investigated. HYPOTHESIS: The present study was designed to determine whether the plasma ADMA level predicts the presence of CAD independently, and whether the plasma ADMA level correlates with the extent and severity of coronary atherosclerosis. METHODS: In all, 97 consecutive patients with angina and positive exercise stress test were enrolled prospectively for coronary angiography. According to the result of angiography, the subjects were divided into two groups: Group I (n = 46): patients with normal coronary artery or mild CAD (< 50% stenosis of major coronary arteries); Group 2 (n = 51): patients with significant CAD (> or = 50% stenosis of majorcoronary arteries). Plasma levels of ADMA and L-arginine were determined by high-performance liquid chromatography. In addition, we used coronary atherosclerotic score to assess the extent and severity of CAD. RESULTS: The plasma levels of ADMA in Group 2 patients were significantly higher than those in Group 1 patients (0.66 +/- 0.17 microM vs. 0.44 +/- 0.09 microM, p < 0.001); these were accompanied by significantly lower plasma L-arginine/ADMA ratio in patients with significant CAD (Group 1 vs. 2: 194.0 +/- 55.3 vs. 136.7 +/- 50.3, p < 0.001). In a multivariate stepwise logistic regression analysis, both plasma ADMA level and plasma L-arginine/ADMA ratio were identified as independent predictors for CAD. Moreover, there were significant positive and negative correlations between coronary atherosclerotic score and plasma ADMA level as well as plasma L-arginine/ADMA ratio, respectively (plasma ADMA level: r = 0.518, p < 0.001; L-arginine/ADMA ratio: r = -0.430, p < 0.001). CONCLUSIONS: Both plasma ADMA level and plasma L-arginine/ADMA ratio were useful in predicting the presence of significant CAD and correlated significantly with the extent and severity of coronary atherosclerosis. Our findings suggest that plasma ADMA level may be a novel marker of CAD.

Factors associated with behavior modification for cardiovascular risk factors in patients with coronary artery disease in northern Taiwan.

BACKGROUND: Studies have demonstrated that improvement in cardiovascular risk factors may contribute to reduced coronary artery disease (CAD) morbidity and mortality, improved patient outcomes, and lower medical costs associated with treating heart disease. PURPOSE: The purpose of this study was to understand the coronary risk factor profile, to have the knowledge of risk factors, to understand the modifying behaviors, and to understand the factors associated with modifying behaviors of cardiovascular risk factors among patients with CAD in northern Taiwan. METHODS: A cross-sectional design was used in this study. Using nonprobability sampling, 156 patients diagnosed with CAD were interviewed and asked to complete a structural questionnaire in cardiovascular clinics at three medical centers in northern Taiwan. Data were analyzed by descriptive analysis, Pearson's correlation, chi-square tests, and stepwise multiple regression. RESULTS: A total of 38% of variance of modifying behaviors was explained by self-efficacy, actual risk factors, work status, and health beliefs. Self-efficacy was the strongest predictor of behavior to modify cardiovascular risk factors. Age and type "A" personality were the two leading cardiovascular risk factors for the participants. Most participants could perform modifying behaviors such as taking medications, eating an appropriate diet, and following specific lifestyle recommendations. However, participants had relatively lower adherence to monitoring blood pressure, exercising regularly, and controlling weight. CONCLUSIONS/IMPLICATIONS FOR PRACTICE: Nurses should assess patient cardiovascular risk factors, health beliefs, and self-efficacy and then provide comprehensive and adequate instruction to each based on his or her specific risk factors.

A randomized, double-blind comparison of cerivastatin and lovastatin for treatment of primary hypercholesterolemia.

BACKGROUND: The efficacy and safety of the new statin, cerivastatin, in the Chinese patients with primary hypercholesterolemia remains to be determined. METHODS: In this prospective, double-blind, parallel-group study, patients with primary hypercholesterolemia were randomized to treatment with cerivastatin, 0.3 mg (n = 21) or lovastatin, 20 mg (n = 22), for 8 weeks. The primary efficacy variable was percentage change of low-density lipoprotein (LDL) cholesterol from baseline. The secondary efficacy variables were percentage change of total cholesterol, triglycerides and high-density lipoprotein (HDL) cholesterol. RESULTS.:Both cerivastatin and lovastatin effectively reduced LDL cholesterol (-33.2% vs. -29.3%, p = 0.63), total cholesterol (-25% vs. -20%, p = 0.10), and triglycerides (-21% vs. -14%,p = 0.27) (all p < 0.0001 for comparison with baseline), and slight increased HDL cholesterol (+2% vs. +8%, p = 0.008) over the 8-week treatment period. The LDL cholesterol responsive rates according to the recommendations from the National Cholesterol Educational Panel (NCEP) were 43% and 32% for cerivastatin and lovastatin, respectively. The adverse event profiles of cerivastatin and lovastatin were similar. CONCLUSIONS: Cerivastatin 0.3 mg once daily is as effective and safe as lovastatin 20 mg once daily in lowering LDL and total cholesterol in Chinese patients with primary hypercholesterolemia.

Plasma levels of asymmetrical dimethylarginine and adverse cardiovascular events after percutaneous coronary intervention.

AIMS: We investigated the predictive value of plasma concentration of asymmetrical dimethylarginine (ADMA) on clinical outcome in patients undergoing percutaneous coronary intervention (PCI). METHODS AND RESULTS: One-hundred and fifty-three consecutive patients with stable angina and undergoing PCI were prospectively enrolled for clinical follow-up. Plasma ADMA levels were determined before procedure by high performance liquid chromatography. The major adverse cardiovascular events included cardiovascular death, myocardial infarction, and repeat revascularization of target vessels. Patients were grouped into tertiles according to their plasma ADMA levels. Over a follow-up period of 16 months (median), cardiovascular events occurred in 6 patients of tertile I (<0.50microM), in 17 patients of tertile II (0.50-0.62microM), and in 28 patients of tertile III (>0.62microM), P<0.001. By multivariate analysis, tertiles of ADMA levels were independently associated with a higher risk of adverse cardiovascular events after PCI (relative risk: tertile II vs I: 3.0 [1.2-7.7], P=0.022; tertile III vs I: 5.3 [2.2-12.9], P<0.001). Moreover, plasma ADMA level in the highest tertile also appeared as a significant risk factor of subsequent death and non-fatal myocardial infarction after PCI (tertile III vs I, P=0.04). CONCLUSION: Pre-procedural plasma ADMA levels may independently predict subsequent adverse cardiovascular events in patients undergoing PCI. Measurement of plasma ADMA levels could provide a rationale for risk stratification of patients by measuring ADMA levels before intervention.

High-resolution mapping around the crista terminalis during typical atrial flutter: new insights into mechanisms.

INTRODUCTION: The aim of this study was to delineate activation patterns around the crista terminalis (CT) using high-resolution noncontact mapping. METHODS AND RESULTS: Twenty-six patients with typical atrial flutter (20 counterclockwise and 6 clockwise) were enrolled in the study. A noncontact mapping system was used to map atrial flutter. There were three activation patterns around the line(s) of block. Type I (n = 6) showed activation around a single complete line of block located in the CT. Type II (n = 17) showed activation around a single incomplete line of block with a conduction gap in the CT. Type III (n = 3) showed activation around double lines of block, one located in the CT and the other located in the sinus venosa region. Simultaneous activation around the tricuspid annulus and through the CT gap could result in double loop reentry (n = 12). After successful ablation of the cavotricuspid isthmus (CTI) in 24 patients, upper loop reentry was still induced in 12 patients with double loop reentry. Subsequent ablation of the CT gap was performed successfully in these 12 patients, and no arrhythmia was inducible thereafter. During the follow-up period of 8.4 +/- 4.1 months, there was no recurrence of atrial flutter in any patient. CONCLUSION: During typical atrial flutter, the CT might be an incomplete barrier. Simultaneous conduction through the CTI and CT gap could result in double loop reentry. Radiofrequency ablation of the CTI and CT gap was effective in eliminating this arrhythmia.

Volume status and blood pressure during long-term hemodialysis: role of ventricular stiffness.

The importance of volume status on blood pressure in hemodialysis patients has long been recognized. We hypothesized that the enhanced volume dependency of blood pressure is partly determined by ventricular stiffness at end systole. A total of 115 long-term hemodialysis patients were invited to receive a comprehensive, noninvasive cardiovascular examination. End-systolic elastance was determined by using a novel, noninvasive echo-Doppler technique. The positive ratios of the interdialytic systolic blood pressure change vs weight gain during the subsequent 25 hemodialysis sessions were averaged to obtain the volume sensitivity index (mm Hg/kg). The averaged interdialytic weight gain per fat-free mass was correlated significantly with averaged percent change in systolic blood pressure (r=0.45, P<0.001). The estimated end-systolic elastance at baseline was significantly correlated with subsequently observed volume sensitivity index (volume sensitivity index=[1.17xend-systolic elastance]+6.4; r=0.34, P=0.001). End-systolic elastance was also significantly correlated with various vascular function parameters, including effective arterial elastance (r=0.48, P<0.001), pulse wave velocity (r=0.30, P=0.001), carotid augmentation index (r=0.31, P<0.001), and aortic compliance (r=-0.49, P<0.001). The results suggest that end-systolic elastance, a direct measure of left ventricular mechanical properties at end systole, is coupled to arterial mechanical properties and predicts the extent of subsequent interdialytic systolic blood pressure rise relative to weight gain. Therefore, ventricular stiffness at end systole is a determinant of the enhanced volume sensitivity of blood pressure in hemodialysis patients.