Christopher B. Pepper

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The long QT syndrome (LQTS) is a condition characterized by abnormal prolongation of the QT interval with an associated risk of ventricular arrhythmias and sudden cardiac death. Congenital forms of LQTS arise due to rare and highly penetrant mutations that segregate in a Mendelian fashion. Over the years, multiple mutations in genes encoding ion channels(More)
Over the past two decades the quest for quantitative evaluation of left ventricular function and regional wall motion has escalated, allowing several aspects of myocardial contractile patterns to be quantified, both during stress echocardiography and in the assessment of dyssynchrony. Most of the literature to date has used Tissue Doppler Imaging (TDI)(More)
Risk assessment is central to the management of acute coronary syndromes. Often, however, assessment is not complete until the troponin concentration is available. Using 2 multicenter prospective observational studies (Evaluation of Methods and Management of Acute Coronary Events [EMMACE] 2, test cohort, 1,843 patients; and EMMACE-1, validation cohort, 550(More)
AIMS Two-dimensional (2D) strain imaging from speckle tracking is a Doppler independent technique allowing assessment of left ventricular (LV) strain (ɛ); systolic strain rate (SRs') and early diastolic strain rate (SRe') in the radial and circumferential planes. We set out to investigate whether (i) these parameters facilitated assessment of dyssynchronous(More)
A reconnaissance study was undertaken to determine potential contaminant exposures to children through soil from elementary school playgrounds. Soil samples were collected from areas along the Texas-Mexico border, inland areas (soils from elementary school yards in cities/towns within the state of Texas), and three National Parks (one on the border, one in(More)
Endothelial cells within the heart release a number of substances that modulate myocardial contractile function. These agents include nitric oxide, endothelin, prostanoids, adenylpurines, and other substances that have so far been characterized only in bioassay studies. A notable feature of many of these agents is that they influence contractile behavior(More)
Previous studies have shown that cardiac endothelial cells release substances that influence myocardial contraction. Since PO2 is an important stimulus that modulates endothelial function, we investigated the effects of acute moderate hypoxia and reoxygenation on the release of cardioactive factors by endothelial cells. Endothelial cells cultured from(More)
Stereocilia are described in a group of guinea pigs with abnormal conformation of the outer hair cell stereociliary bundles. Rows of stereocilia were found which were circular instead of V- or W-shaped, and rotated or even reversed in orientation with respect to normal. The stereocilia have however a normal gradation in heights of the rows of stereocilia,(More)
BACKGROUND While information on how cardiac resynchronisation therapy (CRT) affects cardiac performance at rest is readily available, the mechanisms whereby CRT alters cardiac function during maximal exercise are unclear. AIMS We examined the medium-term effects of CRT on cardiac and physical functional reserve of patients with severe heart failure (CHF)(More)