Papers by Richard Schuessler
Heart Rhythm, 2005
Heart Rhythm, Volume 2, Issue 5, Pages S15, May 2005, Authors:Spencer J. Melby, MD; Anson M. Lee,... more Heart Rhythm, Volume 2, Issue 5, Pages S15, May 2005, Authors:Spencer J. Melby, MD; Anson M. Lee, BS; Richard B. Schuessler, PhD; Ralph J. Damiano, MD.
http://ats.ctsnetjournals.org/cgi/content/full/84/3/857 located on the World Wide Web at:
Circulation, Oct 31, 2007
There are many challenging tasks in the design of the beamline instrumentation that relate to hig... more There are many challenging tasks in the design of the beamline instrumentation that relate to high precision positioning mechanism for users at a third-generation synchrotron radiation source, such as the 7 GeV Advanced Photon Source (APS). Over the last few years, progress has been made in the development of novel mechanisms with high positioning resolution and high stability at the APS. Applications include: a high-energy-resolution monochromator, x-ray nanoprobe scanning stages, and a sample-exchange automation system for x-ray cryobiocrystallography. In this paper, the particular design upgrades, as well as the new mechanism design specifications, are summarized.
The Annals of Thoracic Surgery, 2015
Expanded polytetrafluoroethylene suture is commonly used for chordal replacement in mitral valve ... more Expanded polytetrafluoroethylene suture is commonly used for chordal replacement in mitral valve repair, but due to material characteristics, knots can unravel. Our aim was to determine the knot security, including how many throws are necessary to prevent knot failure, with Gore-Tex (W.L. Gore and Associates, Elkton, MD) and the newly available Chord-X (On-X Life Technologies Inc, Austin, TX). Knots were evaluated for maximal load based on: number of throws (6, 8, 10, and 12), tension to secure each throw (10%, 50%, and 85%) and suture type (Gore-Tex CV-5 and Chord-X 3-0). A physiologic force of 2 N was used for comparison. We evaluated 240 knots. For all knots, the mean load to failure was 11.1 ± 5.8 N. Failure occurred due to unraveling in 141 knots (59%) at 7.1 ± 4.1 N and to breaking in 99 (41%) at 16.7 ± 2.0 N (p < 0.01). Gore-Tex failed at higher loads (12.6 ± 6.0N vs 9.5 ± 5.2 N, p < 0.01); however, an equivalent number, 6 Gore-Tex and 6 Chord-X, unraveled at 2 N, all with fewer than 10 throws. Expanded polytetrafluoroethylene has adequate strength to prevent breakage; however, a risk of knot unraveling at physiologic conditions exists when fewer than 10 throws are performed.
The Annals of Thoracic Surgery, 2015
Expanded polytetrafluoroethylene suture is commonly used for chordal replacement in mitral valve ... more Expanded polytetrafluoroethylene suture is commonly used for chordal replacement in mitral valve repair, but due to material characteristics, knots can unravel. Our aim was to determine the knot security, including how many throws are necessary to prevent knot failure, with Gore-Tex (W.L. Gore and Associates, Elkton, MD) and the newly available Chord-X (On-X Life Technologies Inc, Austin, TX). Knots were evaluated for maximal load based on: number of throws (6, 8, 10, and 12), tension to secure each throw (10%, 50%, and 85%) and suture type (Gore-Tex CV-5 and Chord-X 3-0). A physiologic force of 2 N was used for comparison. We evaluated 240 knots. For all knots, the mean load to failure was 11.1 ± 5.8 N. Failure occurred due to unraveling in 141 knots (59%) at 7.1 ± 4.1 N and to breaking in 99 (41%) at 16.7 ± 2.0 N (p < 0.01). Gore-Tex failed at higher loads (12.6 ± 6.0N vs 9.5 ± 5.2 N, p < 0.01); however, an equivalent number, 6 Gore-Tex and 6 Chord-X, unraveled at 2 N, all with fewer than 10 throws. Expanded polytetrafluoroethylene has adequate strength to prevent breakage; however, a risk of knot unraveling at physiologic conditions exists when fewer than 10 throws are performed.
Background. Infective endocarditis is associated with a high rate of long-term mortality. Patient... more Background. Infective endocarditis is associated with a high rate of long-term mortality. Patients with a history of intravenous drug use (IVDU) are at increased risk for infective endocarditis. However, few studies have reported results of surgical treatment on this population. We present 19.5 years of experience with surgically treated patients with infective endocarditis.
Background. Infective endocarditis is associated with a high rate of long-term mortality. Patient... more Background. Infective endocarditis is associated with a high rate of long-term mortality. Patients with a history of intravenous drug use (IVDU) are at increased risk for infective endocarditis. However, few studies have reported results of surgical treatment on this population. We present 19.5 years of experience with surgically treated patients with infective endocarditis.
American Journal of Physiology Heart and Circulatory Physiology, Mar 1, 2001
This study reports the comparative quantitative, morphological, and electrophysiological properti... more This study reports the comparative quantitative, morphological, and electrophysiological properties of two pacemaker cell types, spider and spindle-shaped cells, isolated from the rabbit sinoatrial node. Isolated nodal cells were studied with perforated and ruptured patch whole cell recording techniques. The basic spontaneous cycle length of the spider cells was 381 +/- 12 ms, and the basic spontaneous cycle length of the spindle cells was 456 +/- 17 ms (n = 12, P < 0.05). The spider cells had a more positive maximum diastolic potential (-54 +/- 1 mV) compared with the spindle cells (-68 +/- 1mV, P < 0.05). The overshoot and action potential amplitudes were also smaller in the spider cells. The hyperpolarization-activated inward (I(f)) current density, measured from their tail currents, was 15 +/- 1.3 pA/pF for the spider cells and 9 +/- 0.7 pA/pF for the spindle cells (P < 0.01). I(f) current activation voltage was more positive in the spider cells than the spindle cells. Isoproterenol (1 microM) decreased the spontaneous cycle length of the spider cells by 28 +/- 3% and the spindle cells by 20 +/- 1.5% (P < 0.05). Acetylcholine (0.5 microM) hyperpolarized the membrane potential of the spider cells to -86 +/- 0.7 mV and the spindle cells to -76 +/- 0.8 mV (P < 0.05). In summary, there are at least two distinct pacemaker cell types in the sinus node with different electrophysiological characteristics.
J Amer Coll Surgeons, 2008
during the last five years showed equivalent survival (89% vs 79%, pÏ0.3), which is in contrast t... more during the last five years showed equivalent survival (89% vs 79%, pÏ0.3), which is in contrast to data from the previous ten years that favored survival in the SLT group (70% vs 45%, pÏ0.16).
Innovations Technology and Techniques in Cardiothoracic and Vascular Surgery, Aug 1, 2006
Background: Microwave energy is commonly used on the beating heart to create lesions for the surg... more Background: Microwave energy is commonly used on the beating heart to create lesions for the surgical treatment of atrial fibrillation. However, lesion transmurality is likely to depend on several factors including tissue thickness and blood flow. This study was designed to determine the effect of cavitary blood flow on transmurality of acute atrial lesions with the FLEX 10 (Guidant Corporation, Santa Clara, Calif ) microwave device.
Circulation, Nov 23, 2010
J Amer Coll Surgeons, 2005
Journal of the American College of Surgeons, Volume 201, Issue 3, Pages S23, September 2005, Auth... more Journal of the American College of Surgeons, Volume 201, Issue 3, Pages S23, September 2005, Authors:Spencer J. Melby, MD; Anson M. Lee, BS; Andreas Zierer, MD; John P. Boineau, MD; Richard B. Schuessler, PhD; Ralph J. Damiano, MD.
Uploads
Papers by Richard Schuessler