Danna A Spears

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Epidemiologic evidence has demonstrated that air pollution may impair cardiovascular health, leading to potentially life-threatening arrhythmias. Efforts have been made, with the use of epidemiologic data and controlled exposures in diverse animal and human populations, to verify the relationship between air pollution and arrhythmias. The purpose of this(More)
BACKGROUND Bipolar voltage mapping has a role in defining endocardial-based scar in postinfarct patients undergoing ventricular tachycardia catheter ablation. The utility of bipolar and unipolar voltages in characterizing scar has not been evaluated in patients with nonischemic cardiomyopathy. OBJECTIVE To relate left ventricular (LV) endocardial bipolar(More)
OBJECTIVES We tested the hypothesis that exposure to concentrated ambient particles (CAP) and/or ozone (O(3)) would increase dispersion of ventricular repolarization. BACKGROUND Elevated levels of air pollution are associated with cardiac arrhythmias through mechanisms yet to be elucidated. METHODS Each of 25 volunteers (18 to 50 years of age) had four(More)
Atrial fibrillation (AF), the most common arrhythmia, is a growing epidemic with substantial morbidity and economic burden. Mechanisms underlying vulnerability to AF remain poorly understood, which contributes to the current lack of highly effective therapies. Recognizing mechanistic subtypes of AF may guide an individualized approach to patient management.(More)
A sudden unexplained death is felt to be due to a primary arrhythmic disorder when no structural heart disease is found on autopsy, and there is no preceding documentation of heart disease. In these cases, death is presumed to be secondary to a lethal and potentially heritable abnormality of cardiac ion channel function. These channelopathies include(More)
AIMS Current conventional ablation strategies for ventricular tachycardia (VT) aim to interrupt reentrant circuits by creating ablation lesions. However, the critical components of reentrant VT circuits may be located at deep intramural sites. We hypothesized that bipolar ablations would create deeper lesions than unipolar ablation in human hearts. (More)
Arsenic and selenium compounds may be emitted to the environment during coal conversion processes, although some compounds are retained in the fly ashes, in different proportions depending on the characteristics of the ashes and process conditions. The possibility of optimizing the conditions to achieve better trace element retention appears to be an(More)
BACKGROUND Nonsustained ventricular tachycardia (NSVT) detected by ambulatory Holter (Holter NSVT) is a major risk factor for sudden cardiac death in hypertrophic cardiomyopathy (HCM). We hypothesized that the prognostic utility of Holter NSVT in HCM would improve with prolonged monitoring and a higher heart rate cut-off for detection. METHODS We enrolled(More)