Circulation. Arrhythmia and electrophysiology
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Circ Arrhythm Electrophysiol · Oct 2011
Iron overload decreases CaV1.3-dependent L-type Ca2+ currents leading to bradycardia, altered electrical conduction, and atrial fibrillation.
Chronic iron overload (CIO) is associated with blood disorders such as thalassemias and hemochromatosis. A major prognostic indicator of survival in patients with CIO is iron-mediated cardiomyopathy characterized by contractile dysfunction and electrical disturbances, including slow heart rate (bradycardia) and heart block. ⋯ Our results demonstrate that CIO selectively reduces Ca(V)1.3-mediated I(Ca,L), leading to bradycardia, slowing of electrical conduction, and atrial fibrillation as seen in patients with iron overload.
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Circ Arrhythm Electrophysiol · Oct 2011
Randomized Controlled Trial Multicenter StudyA randomized, placebo-controlled study of vernakalant (oral) for the prevention of atrial fibrillation recurrence after cardioversion.
Vernakalant, a relatively atrial-selective antiarrhythmic drug, has previously demonstrated efficacy for the acute conversion of atrial fibrillation (AF) to sinus rhythm. This study was designed to determine the most appropriate oral dose of vernakalant for the prevention of AF recurrence postcardioversion. ⋯ URL: http://www.clinicaltrials.gov. Unique identifier: NCT00526136.
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Circ Arrhythm Electrophysiol · Oct 2011
Comparative StudySuccess of ablation for atrial fibrillation in isolated left ventricular diastolic dysfunction: a comparison to systolic dysfunction and normal ventricular function.
The efficacy of radiofrequency ablation for atrial fibrillation (AF) in patients with left ventricular (LV) systolic dysfunction and isolated diastolic dysfunction is uncertain. ⋯ Although an ablative approach for AF in patients with systolic or diastolic dysfunction is associated with an increased long-term recurrence risk, there is potential for substantial quality-of-life improvement and LV functional benefit.
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Circ Arrhythm Electrophysiol · Oct 2011
Influence of race on atrial fibrillation after cardiac surgery.
Despite having fewer risk factors for atrial fibrillation (AF), white patients have a greater prevalence of AF in the community than black patients, and a genetic basis has been postulated. However, it is unknown whether occurrence of new-onset AF after cardiac surgery is different in white versus black patients, and secondarily, other non-Caucasian patients. ⋯ White patients had a markedly higher risk of postoperative AF than black and other non-Caucasian patients. The cause for racial differences of arrhythmic risk is unknown, but a genetic predisposition is plausible. Our results have implications for risk stratification and mechanistic understanding of postoperative AF.
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Circ Arrhythm Electrophysiol · Aug 2011
Comparative StudyDifferences in repeating patterns of complex fractionated left atrial electrograms in longstanding persistent atrial fibrillation as compared with paroxysmal atrial fibrillation.
Complex fractionated atrial electrograms (CFAE) are morphologically more uniform in persistent longstanding as compared with paroxysmal atrial fibrillation (AF). It was hypothesized that this may result from a greater degree of repetitiveness in CFAE patterns at disparate left atrial (LA) sites in longstanding AF. ⋯ In paroxysmal AF, CFAE repetitiveness is low and randomness high outside the PVs, particularly the left superior PV. As evolution to persistent longstanding AF occurs, CFAE repetitiveness becomes more uniformly distributed at disparate sites, possibly signifying an increasing number of drivers from remote PVs.