Heart rhythm : the official journal of the Heart Rhythm Society
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Sudden cardiac death increases during winter months in both men and women. The heart rate-corrected QT (QTc) interval exhibits circadian variation. However, little is known about QTc interval variation with month of year. ⋯ Significant seasonal variation in QTc interval exists among male subjects >or=18 years of age with normal baseline ECGs, with the QTc interval being longest in October. No significant variation was seen for women.
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Randomized Controlled Trial Multicenter Study
Long-term outcomes of left bundle branch block in high-risk survivors of acute myocardial infarction: the VALIANT experience.
In survivors of myocardial infarction (MI), new left bundle branch block (LBBB) is associated with adverse outcomes, but its impact is not well described in post-MI patients with left ventricular (LV) systolic dysfunction and/or heart failure (HF). ⋯ In post-MI survivors with LV systolic dysfunction and/or HF, new LBBB was an independent predictor of all major adverse cardiovascular outcomes during long-term follow-up. This readily available ECG marker should be considered a major risk factor for long-term cardiovascular complications in high-risk patients after MI.
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Anticoagulation therapy in patients with atrial fibrillation is important. This review consists of three parts: chronic anticoagulation, anticoagulation for cardioversion, and a brief comment on anticoagulation around the time of left atrial radiofrequency ablation. The risk stratification scheme of the American College of Cardiology/American Heart Association/European Society of Cardiology (ACC/AHA/ESC) guidelines for chronic anticoagulation is briefly reviewed. ⋯ The risk of thromboembolism according to international normalized ratio and use of low-molecular-weight heparin as an alternative to warfarin are discussed. Anticoagulation before and after left atrial radiofrequency ablation is empirical, and long-term anticoagulation seems advisable for high risk patients at the present time. The two most pressing needs for further investigation are (1) clarification, simplification, and consolidated of risk stratification schemes and treatment recommendations and (2) discovery of alternatives to warfarin.
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Transesophageal echocardiography (TEE) is routinely used to exclude atrial thrombus prior to cardioversion of atrial fibrillation (AF). Because the TEE probe lies adjacent to the atria, cardioversion using an electrode attached to the TEE probe should allow for immediate low-energy transesophageal cardioversion. ⋯ Atrial thrombus exclusion and transesophageal cardioversion of AF via a disposable cardioversion sheath offers the opportunity to perform transesophageal cardioversion and TEE thrombus exclusion during one sedation. It may not be suitable for use in patients with gastroesophageal reflux disease. Transesophageal cardioversion may establish sinus rhythm in selected patients refractory to transthoracic cardioversion.