Circulation
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Multicenter Study Comparative Study Clinical Trial
Diagnosis of sleep-related breathing disorders by visual analysis of transthoracic impedance signals in pacemakers.
Minute ventilation sensors of cardiac pacemakers measure ventilation by means of transthoracic impedance changes between the pacemaker case and the electrode tip. We investigated whether this technique might detect sleep-related breathing disorders. ⋯ Detection of apnea/hypopnea events by pacemaker minute ventilation sensors is feasible and accurate compared with laboratory polysomnography. This technique might be useful to screen and monitor sleep-related breathing disorders in pacemaker patients.
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Randomized Controlled Trial Multicenter Study Comparative Study Clinical Trial
Prospective randomized multicenter trial of empirical antitachycardia pacing versus shocks for spontaneous rapid ventricular tachycardia in patients with implantable cardioverter-defibrillators: Pacing Fast Ventricular Tachycardia Reduces Shock Therapies (PainFREE Rx II) trial results.
Successful antitachycardia pacing (ATP) terminates ventricular tachycardia (VT) up to 250 bpm without the need for painful shocks in implantable cardioverter-defibrillator (ICD) patients. Fast VT (FVT) >200 bpm is often treated by shock because of safety concerns, however. This prospective, randomized, multicenter trial compares the safety and utility of empirical ATP with shocks for FVT in a broad ICD population. ⋯ Compared with shocks, empirical ATP for FVT is highly effective, is equally safe, and improves quality of life. ATP may be the preferred FVT therapy in most ICD patients.
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Pulmonary hypertension induced by chronic hypoxia is characterized by thickening of pulmonary artery walls, elevated pulmonary vascular resistance, and right-heart failure. Prostacyclin analogues reduce pulmonary pressures in this condition; raising the possibility that cycloxygenase-2 (COX-2) modulates the response of the pulmonary vasculature to hypoxia. ⋯ COX-2 expression is increased and regulates platelet activity and intravascular thrombosis in hypoxia-induced pulmonary hypertension.
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Randomized Controlled Trial Clinical Trial
Mortality and morbidity reduction with Candesartan in patients with chronic heart failure and left ventricular systolic dysfunction: results of the CHARM low-left ventricular ejection fraction trials.
Patients with symptomatic chronic heart failure (CHF) and reduced left ventricular ejection fraction (LVEF) have a high risk of death and hospitalization for CHF deterioration despite therapies with angiotensin-converting enzyme (ACE) inhibitors, beta-blockers, and even an aldosterone antagonist. To determine whether the angiotensin-receptor blocker (ARB) candesartan decreases cardiovascular mortality, morbidity, and all-cause mortality in patients with CHF and depressed LVEF, a prespecified analysis of the combined Candesartan in Heart Failure Assessment of Reduction in Mortality and morbidity (CHARM) low LVEF trials was performed. CHARM is a randomized, double-blind, placebo-controlled, multicenter, international trial program. ⋯ Candesartan significantly reduces all-cause mortality, cardiovascular death, and heart failure hospitalizations in patients with CHF and LVEF < or =40% when added to standard therapies including ACE inhibitors, beta-blockers, and an aldosterone antagonist. Routine monitoring of blood pressure, serum creatinine, and serum potassium is warranted.
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Meta Analysis
Selecting patients with atrial fibrillation for anticoagulation: stroke risk stratification in patients taking aspirin.
The rate of stroke in atrial fibrillation (AF) depends on the presence of comorbid conditions and the use of antithrombotic therapy. Although adjusted-dose warfarin is superior to aspirin for reducing stroke in AF, the absolute risk reduction of warfarin depends on the stroke rate with aspirin. This prospective cohort study tested the predictive accuracy of 5 stroke risk stratification schemes. ⋯ Patients with AF who have high and low rates of stroke when given aspirin can be reliably identified, allowing selection of antithrombotic prophylaxis to be individualized.