Global right atrial mapping delineates double posterior lines of block in patients with typical atrial flutter: a study using a three dimensional noncontact mapping system

Double Posterior Lines of Block in Typical Atrial Flutter. INTRODUCTION: The crista terminalis (CT) has been shown to be a barrier to transverse conduction during typical atrial flutter (AFL). However, some studies have demonstrated the presence of functional block in the sinus venosa region but not at the CT. The aim of this study was to define these regions of block in the right atrium using a three-dimensional noncontact mapping system. METHODS AND RESULTS: In 39 AFL patients (33 men and six women, mean age 56 +/- 13 years), a noncontact multielectrode array was used to reconstruct electrograms in the right atrium. Isochronal and isopotential propagation mapping was performed during AFL and during pacing from the coronary sinus ostium and the low lateral wall (cycle length from 600 to 240 msec) in sinus rhythm after creation of isthmus block. A single line of block along the CT area was found in 18 patients (46%). Two lines of block were found in 21 patients (54%), with the first line located along the CT area. The second was located in the sinus venosa region in 20 patients (51%) and in the lateral wall in 1 patient (3%). In all patients, the block in the lower part of the CT was observed during AFL (60%) and during pacing at all cycle lengths (48%-62%). The length and proportion of block were inversely proportional to pacing cycle length. CONCLUSION: Double lines of block were frequently observed in patients with AFL, and both lines may form the posterior boundaries of the AFL circuit. Block was fixed in the lower part of the CT and was functional in the upper part of the CT.     

Reducing atrial tachycardia and atrial fibrillation episodes with a prevention and treatment device and tailored treatment

BACKGROUND: Pacemaker treatment of known trigger mechanisms for atrial tachyarrhythmias (AT) and atrial fibrillation (AF) has shown reduction in the incidence of AF. A new arrhythmia management device, which included storage of AT/AF (for tailoring treatment) and three prevention algorithms and one for treatment, was examined in order to identify the influence on arrhythmia episodes over a 12-month follow-up (FU) period. METHODS: Twenty-three consecutive patients with known tachybradyarrhythmias were examined. Seven patients had to be excluded (two outliers, four developed permanent AF, one had no detection algorithm turned on at implantation). The remaining 16 patients showed 2723 episodes (675 treated episodes) for evaluation of the effect on episodes/month/patient (e/m/p), treatment success, duration of episodes, circadian distribution and quality of life. RESULTS: The AT/AF e/m/p were reduced from 37 +/- 102 e/m/p at 1-month FU to 16 +/- 48 e/m/p at 3-month FU, 15 +/- 48 e/m/p at 6-month FU and 10 +/- 28 e/m/p at 12-month FU (p < 0.05), according to fewer subjective symptoms. Treatment success remained stable during the observation period (29-40%). Only minor changes in the duration of episodes and the distribution of start times were observed. CONCLUSION: Tailoring treatment by the pacemaker examined with several prevention and treatment algorithms reduces e/m/p and might be a promising supplement in the treatment of selected patients with known AT/AF and bradycardia.     

Color Doppler tissue velocity imaging can disclose systolic left ventricular asynchrony independent of the QRS morphology in patients with severe heart failure

A QRS width greater than 120 ms is assumed to be a marker of inter- and intraventricular asynchrony in severe heart failure (HF) patients. Color Doppler tissue velocity imaging (c-TVI) with a time resolution of 10 ms was used to study regional left ventricular (LV) longitudinal systolic contraction pattern in HF patients with left and right bundle branch block (LBBB and RBBB) and in patients with normal QRS width. We studied 12 women and 23 men with severe HF, with a mean age of 66 +/- 11 years in New York Heart Association functional Class 2.9 +/- 0.6. Twenty patients had LBBB and 10 of those were accepted for cardiac resynchronization therapy by biventricular pacing (CRT). Ten patients had normal QRS width, and five had RBBB. In the echocardiographic apical four chamber view, regional peak LV tissue velocities and regional LV time differences of peak tissue velocities were compared at basal and mid-LV segments. There were no significant differences in regional mean peak tissue velocities among the patient groups. In patients with LBBB accepted for CRT, the LV lateral free-wall movement at basal LV was 29 ms delayed during main systole, almost significantly different from LBBB patients not accepted for CRT (P = 0.075). Even in HF patients with normal QRS width or RBBB, significant asynchronous longitudinal LV contraction was observed. Conclusions: For the detection of regional longitudinal LV contraction asynchrony in patients with severe HF, supplementary methods to the surface ECG, such as c-TVI, are strongly recommended.     

Feasibility of color doppler tissue velocity imaging for assessment of regional timing of left ventricular longitudinal movement

OBJECTIVE--The feasibility of color Doppler tissue velocity imaging (c-TVI) with a high time resolution of 10 ms for simultaneous measurement of the temporal characteristics of regional left ventricular (LV) tissue velocities at different LV sites was examined. Methods and results--In 20 subjects with structurally normal hearts, inter- and intraobserver agreement and the beat-to-beat variation were tested in c-TVI profiles from basal and mid-LV segments of the interventricular septum (IS) and of the lateral free wall (LFW). For peak tissue velocities a mean error of less than 1 cm/s was demonstrated. For systolic regional LV velocity time difference, the mean error was +/- 5 ms, with the best agreement when sampling from basal LV sites. For diastolic regional LV velocity time differences, the mean error was +/- 12 ms. The longitudinal LV movement pattern demonstrated a pattern of incremental tissue velocity from basal to mid-LV, and from IS to LFW sites. Conclusion--The c-TVI method has acceptable inter- and intraobserver agreement and is sufficiently accurate to disclose regional time aspects of LV contraction and relaxation.     

Saturday opening of alcohol retail shops in Sweden: an impact analysis

OBJECTIVE: The objective of this study was to assess the impact of Saturday opening of alcohol retail shops in Sweden. METHOD: An experimental design was applied. Prior to February 2000, all alcohol monopoly outlets we closed on Saturdays. After this date, stores in an experimental area (six counties) were open on Saturdays. In the control area (seven counties) the shops remained closed. To prevent biases resulting from border trade, the experimental and control areas were separated by a border area (seven counties). The outcome measures included alcohol sales and indicators of assaults and drunken driving. The pre-intervention period covered January 1995-January 2000, and the post-intervention period February 2000-June 2001 (17 months). The data were analyzed on a monthly basis through ARIMA-modeling according to the Box-Jenkins technique. RESULTS: The analysis uncovered a statistically significant increase in alcohol sales of 3.3%. There were no significant changes in any of the assault indicators. There was a statistically significant increase in drunken driving (8.3%) on Saturdays-Sundays; however, further analyses suggested this increase was due mainly to a change in the surveillance strategy of the police. CONCLUSIONS: The Saturday opening of alcohol retail shops seems to have increased consumption but not alcohol-related harm. The absence of a significant effect on harm indicators could signify either that no such effect is present or that the design has insufficient power to uncover effects of the expected magnitude.     

Electrophysiologic effects of flecainide acetate in patients with sinus nodal dysfunction

Flecainide acetate (R818) is a new antiarrhythmic agent for oral and intravenous use; it has predominantly class I properties and a long plasma half-life. Electrophysiologic effects were evaluated in 11 patients with sinus nodal dysfunction before administration of flecainide acetate and 15 to 60 minutes after intravenous administration of 1.5 mg/kg body weight of flecainide acetate given over 15 minutes. In 8 of 11 patients the maximal sinus nodal recovery time increased after flecainide acetate. However, the mean maximal sinus nodal recovery time was not statistically significantly increased from 1,929 ± 184 (mean ± standard error of the mean [SEM]) to 2,770 ± 500 ms (p <0.10). The corrected sinus nodal recovery time increased from 875 ± 181 before to 1,727 ± 507 ms after administration of flecainide acetate (p <0.05). The sinus cycle length and sinoatrial conduction time were not significantly changed. Flecainide acetate induced a marked prolongation of the H-V interval (from 41 ± 3 to 52 ± 4 ms [p <0.01]) as well as a significant increase in the A-H interval, QRS duration, and QT₁₀₀ interval. The effective and functional refractory periods of the atria increased by 12% (p <0.01) and 11% (p <0.01), respectively. The atrioventricular (AV) nodal functional refractory period increased significantly by 7% (p <0.01), whereas the 9% prolongation of the effective refractory period was not statistically significant. No side effects were observed. It is concluded that flecainide acetate prolongs atrial and ventricular conduction and refractoriness, and thus appears to be a potent antiarrhythmic agent. However, the sinus nodal function is depressed, and thus caution is advised in the use of flecainide acetate in patients with sinus nodal dysfunction.     

Curative ablation for atrial fibrillation: a systematic review

OBJECTIVE: To perform a systematic review of randomized controlled trials (RCTs) on catheter ablation for atrial fibrillation (AF). BACKGROUND: Radiofrequency catheter (RF)-ablation around pulmonary vein ostia and in left atrium may reduce or prevent recurrence of AF, as documented in observational studies and registry reports; however, few RCTs are available. METHODS: Using relevant search phrases, Cochrane Library, MEDLINE and EMBASE were searched for RCTs, last time in May 2007. Titles and abstracts were screened. When entry criteria were fulfilled, full-text papers were read and graded according to quality and relevance. RESULTS: One thousand and ninety four abstracts were evaluated, and five RCTs included (578 randomized patients). The studies had moderate quality and relevance, but the results were consistent: ablation is better than drug treatment in preventing AF recurrence; the relative risk (95% CI)) one year after ablation ranged from 0.20 (0.08-0.51) to 0.62 (0.39-0.99). CONCLUSIONS: Results from observational and registry studies are confirmed: RF-ablation reduces recurrence rate of AF, and can be done with few serious complications. Limitations are few patients>70 years, and only one year follow-up.     

Treatment of atrial fibrillation by silencing electrical activity in the posterior inter-pulmonary-vein atrium.

AIMS: The recurrence of atrial fibrillation (AF) after pulmonary vein (PV) isolation is still a challenge. We investigated a new approach to treating AF patients by silencing electrical activity in the posterior inter-pulmonary-vein atrium (PIA). METHODS AND RESULTS: Three ablation steps are required to obtain PIA electrical silence: electrical PV isolation, the creation of two lines of lesions between the two superior and inferior PVs and the abolition of residual electrical signals within the PIA. The endpoint was the electrical silence and the inability to pace in the PIA. The posterior inter-pulmonary-vein atrium silence was obtained in 42 AF patients (56 +/- 9 years, four women). Recurrence of AF and atrial flutter was observed in 14 (33.3%) patients after the first procedure. Freedom from atrial arrhythmias after the second procedure was displayed by 94.4, 85.7, and 60.0% of patients with paroxysmal, persistent, and permanent AF, respectively. The left atrium (LA) volume was larger, and the percentages of the silent area of the LA surface and voltages were lower in patients with AF recurrence than in recurrence-free patients. CONCLUSION: Posterior inter-pulmonary-vein atrium electrical silence can greatly decrease the AF recurrence. The clinical AF recurrence may be related to an enlarged LA, a low percentage of electrically silent area, and low voltage in the LA.     

Flux and stability: individual fluctuations, regression towards the mean and collective changes in alcohol consumption

AIM: First, to extend the predictions of the collectivity theory of drinking cultures to contexts of ordinary panel data, thereby integrating collective change and individual fluctuations in consumption. Secondly, to develop a technique for controlling the regression towards the mean effect, in order to estimate the pattern of individual change, net of this effect. DESIGN: The task is, first and foremost, to develop a theoretical model, guided by earlier contributions and empirical results. The applicability of the model is illustrated through re-analyses of panel data on annual intake of alcoholic beverages from the Finnish alcohol reform in 1968-69, and Norwegian panel data from 1975 to 1976. FINDINGS: The model offers a reasonable fit to the data. It is demonstrated that a previous attempt at controlling the regression effect has overlooked a methodological complication, and therefore underestimates the real change. CONCLUSION: Analysis of the Finnish data demonstrates that the large increase in average consumption was due to approximately the same percentage-wise increase in the consumption level of drinkers at all levels, when the regression effect was controlled for. Thus, in absolute terms the increase was largest among the heavier drinkers.     

Becker's rational addiction theory: An empirical test with price elasticities for distilled spirits in Denmark 1911-31

AIM: To test an implication of Becker's rational addiction theory, namely that price changes will lead both to simultaneous consumption changes as well as lagged changes (and potentially also immediate changes if future changes in prices are anticipated). DESIGN: Time-series analysis, first of aggregate sales of distilled spirits and prices, controlled for gross national product (GNP), and secondly of deaths from delirium tremens. SETTING: Denmark 1911-31. Price changes were very large in the period 1916-18 due to shortages during World War I, and the Danish case can be conceived as a natural experiment. FINDINGS: No evidence for lagged price effects in the expected direction was found. On the contrary, the evidence pointed in the opposite direction. The immediate reduction in sales following rising prices are, to some degree, counteracted by an adjustment in the opposite direction the following year. The delirium tremens data confirm this pattern. CONCLUSION: Becker's theory is not confirmed. Several possible explanations are discussed. If the pattern observed in these data is representative of a more general mechanism, current price elasticity estimates may be too high, by ignoring lagged compensatory effects.