This study sought to evaluate the prognostic value of wavelet correlation functions of the signal-averaged electrocardiogram (ECG) for arrhythmic events in patients after myocardial infarction.
...Wavelet transform of the signal-averaged ECG has been shown to be a nonstationary analysis technique describing the time evolution of frequency spectra throughout the QRS complex. To quantify the wavelet transform, we introduced the new concept of the wavelet correlation function.
The relation among wavelet correlation functions, ventricular late potentials and the site of infarction was investigated in 769 men <66 years old who survived the acute phase of myocardial infarction (351 46% anterior, 418 54% inferior infarctions). Signal-averaged ECG recordings were obtained 2 to 3 weeks after infarction. During 6 months of follow-up, 33 patients (4.3%) experienced a malignant arrhythmic event. Wavelet correlation functions of the signal-averaged ECG were evaluated in a time-frequency plane ranging from 25 ms before QRS onset to 25 ms after QRS offset in the frequency range between 40 and 100 Hz.
Patients with an anterior infarction had lower mean wavelet correlation coefficients (p < 0.001) and a lower incidence of ventricular late potentials than patients with an inferior infarction (32.3% vs. 42.7%, p = 0.003). The combination of wavelet correlation functions and late potentials increased the total predictive accuracy from 52% to 72% for inferior and from 64% to 76% for anterior infarctions.
Spectral changes in the signal-averaged QRS complex are more prominent in anterior than inferior infarctions. Combination of late potential analysis and wavelet correlation functions increases the prognostic value for serious arrhythmic events after myocardial infarction.
Persistent atrial fibrillation (AF) causes relevant mortality and cardiovascular and noncardiovascular morbidity. Therefore, maintenance of sinus rhythm is an important clinical goal, especially when ...the patient is symptomatic, despite the fact that current treatment strategies are not sufficient to completely prevent recurrent AF. In addition to underlying atrial disease that predisposes to AF, AF in itself induces structural and electrical adaptations (“electrical remodeling” and “structural remodeling”). Underlying disease processes and parts of structural remodeling are not always reversible. Electrical remodeling, in contrast, is reversed by a few weeks of maintenance of sinus rhythm under experimental conditions. This corresponds to the period when most of the recurrent episodes of AF occur after cardioversion. Antiarrhythmic drugs that prolong the atrial action potential can assist in the prevention of recurrent AF by promoting the reversal of electrical remodeling. Such drugs, which are currently used over long periods after cardioversion, may only be needed until the physiological action potential duration is restored, for example, during the first few weeks after cardioversion of persistent AF. This treatment concept that we call “targeted pharmacological reversal of electrical remodeling” would limit both cost and drug-induced side effects of antiarrhythmic drug therapy after cardioversion. The Flec-SL trial, ISECTN62728743, therefore tests the main hypothesis that targeted pharmacological reversal of electrical remodeling by short-term antiarrhythmic drug therapy for 4 weeks after cardioversion is not inferior to standard long-term antiarrhythmic drug therapy for the prevention of recurrent AF after cardioversion in a parallel group, randomized, multicenter, open, blinded end point analysis design. Based on its effectiveness and pharmacokinetic profile, flecainide is used to test the study hypothesis. The trial uses daily transtelephonic electrocardiographic monitoring for all patients and will be conducted within the German Atrial Fibrillation Competence NETwork (AFNET) to facilitate inclusion of patients from electrophysiologically oriented cardiology centers, ordinary hospitals, and office-based physicians.
Atrial fibrillation (AF) is the most common cardiac arrhythmia. Recent experimental data and retrospective analyses of clinical trials suggest that increased levels of angiotensin II can induce an ...arrhythmogenic atrial substrate, which favours the occurrence of AF. The purpose of the ANTIPAF (Angiotensin II Antagonist in Paroxysmal Atrial Fibrillation) trial is to prove the principal concept that blockade of angiotensin II type 1 receptors with olmesartan medoxomil 40 mg/day suppresses paroxysmal AF episodes during a 12-month follow-up. The ANTIPAF trial is the first placebo-controlled trial analysing the occurrence of AF as the primary study endpoint.
Examination of the study hypothesis in a prospective, randomised, placebo-controlled, double-blind group comparison in patients with documented paroxysmal AF (total of 422 patients) stratified by beta-adrenoceptor antagonist use. The primary endpoint of the study is the percentage of days with documented episodes of paroxysmal AF identified on daily transtelephonic tele-ECG recordings. Patients will record and transmit at least one 1-minute ECG per day independent of symptoms. Furthermore, tele-ECG recordings will be transmitted in any case of symptomatic AF. The present paper summarises the rationale and design of the ANTIPAF trial.
Background
Observational studies from the USA have demonstrated that off-label use of drug-eluting stents (DES) is common. Data on off-label use in Western Europe are limited.
Methods
We analyzed the ...data of consecutive patients receiving DES prospectively enrolled in the multicenter German DES.DE registry (Deutsches Drug-Eluting Stent Register) between October 2005 and October 2006. Off-label use was defined in the presence of one of the following criteria: ST-elevation myocardial infarction, in-stent stenosis, chronic total occlusion, lesions in a bypass graft, in bifurcation or left main stem, stent length per lesion ≥32 mm, and vessel diameter <2.5 or >3.5 mm.
Results
Overall, 4,295 patients were included in this analysis and divided into two groups: 2,366 (55.1%) received DES for off-label and 1,929 (44.9%) for on-label indications. There were substantial differences in the rates of off-label use at the participating hospitals. Patients with off-label DES more often presented with high-risk features such as acute coronary syndrome, cardiogenic shock, congestive heart failure, and more complex coronary anatomy. Among hospital survivors, the incidence of the composite endpoint of death, myocardial infarction and stroke (MACCE) (9.2 vs. 7.4%,
p
< 0.05), and target vessel revascularization (TVR) (11.3 vs. 9.1%,
p
< 0.05) was increased in the off-label group at the 1-year follow-up. However, in the multivariate analysis off-label use was not linked with an elevated risk for MACCE (hazard ratio 0.86, 95% confidence interval 0.62–1.18) and TVR (hazard ratio 1.05, 95% confidence interval 0.78–1.42).
Conclusions
In clinical practice, DES was very frequently used off-label. After adjustment for confounding variables, off-label use was not associated with an increase of adverse events.
Background. We assessed the impact of patient and procedural characteristics on the outcome after emergency coronary artery bypass grafting (CABG) for failed percutaneous transluminal coronary ...angioplasty (PTCA) and temporal changes in these factors.
Methods. Patients who underwent PTCA and subsequent emergency CABG were identified from the databases of the Departments of Cardiology and Cardiothoracic Surgery.
Results. Two periods of clinical practice were compared. In 1989 to 1993, 2,880 PTCAs were performed, 64 patients underwent emergency CABG (2.3%), and 7 patients died (10.9%). During 1994 to 1998, 46 patients of 3,801 PTCAs underwent emergency CABG (1.2%,
p < 0.01), and 7 patients died (15.2%, NS). The average rate of stenting increased from 0.8% to 24% in 1994 to 1998 as well as the frequency of arterial bypass grafts (0% vs 39%). In the latter period, patients were older, were more often females, had more cardiovascular risk factors, a higher Cleveland score (each
p < 0.05), and suffered more often from periprocedural myocardial infarctions (
p < 0.001) and nonfatal periprocedural complications (
p < 0.01).
Conclusions. Although the frequency of emergency CABG after failed PTCA declined, perioperative mortality tended to increase according to an unfavorable shift in patient risk factors and morbidity.
The induction of a complete conduction block of the isthmus between inferior vena cava and tricuspid annulus is considered the best predictor for lack of arrhythmia recurrence if radiofrequency ...catheter ablation for typical atrial flutter is performed. We evaluated a simplified algorithm to determine complete isthmus block that, in our series, had a predictive accuracy of 100% when compared with the gold standard.
KIRCHHOF P., et al.: Prolonged QRS Duration Increases QT Dispersion But Does Not Relate to Arrhythmias in Survivors of Acute Myocardial Infarction. QT dispersion has been suggested and disputed as a ...risk marker for ventricular arrhythmias after myocardial infarction. Delayed ventricular activation after myocardial infarction may affect arrhythmic risk and QT intervals. This study determined if delayed activation as assessed by (1) QRS duration in the 12‐lead ECG and by (2) late potentials in the signal‐averaged ECG affects QT dispersion and its ability to assess arrhythmic risk after myocardial infarction. QT duration, JT duration, QT dispersion, and JT dispersion were compared to QRS duration in the 12‐lead ECG and to late potentials in the signal‐averaged ECG recorded in 724 patients 2–3 weeks after myocardial infarction. Prolonged QRS duration (> 110 ms) and high QRS dispersion increased QT and JT dispersion by 12%–15% (P < 0.05). Presence of late potentials, in contrast, did not change QT dispersion. Only the presence of late potentials (n = 113) was related to arrhythmic events during 6‐month follow‐up. QT dispersion, JT dispersion, QRS duration, and QRS dispersion were equal in patients with (n = 29) and without arrhythmic events (QT disp 80 ± 7 vs 78 ± 1 ms, JT disp 80 ± 6 vs 79 ± 2 ms, mean ± SEM, P > 0.2). In conclusion, prolonged QRS duration increases QT dispersion irrespective of arrhythmic events in survivors of myocardial infarction. Presence of late potentials, in contrast, relates to arrhythmic events but does not affect QT dispersion. Therefore, QT dispersion may not be an adequate parameter to assess arrhythmic risk in survivors of myocardial infarction.
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