G P Walcott

Summary

Affiliation: University of Alabama at Birmingham
Country: USA

Publications

  1. ncbi request reprint Relative efficacy of monophasic and biphasic waveforms for transthoracic defibrillation after short and long durations of ventricular fibrillation
    G P Walcott
    Division of Cardiovascular Diseases, Department of Medicine, University of Alabama at Birmingham, AL, USA
    Circulation 98:2210-5. 1998
  2. pmc Burst stimulation improves hemodynamics during resuscitation after prolonged ventricular fibrillation
    Gregory Walcott
    University of Alabama at Birmingham, Birmingham, AL, USA
    Circ Arrhythm Electrophysiol 2:57-62. 2009
  3. doi request reprint Ventricular fibrillation threshold of rapid short pulses
    Gregory P Walcott
    Cardiac Rhythm Management Laboratory, University of Alabama, Birmingham, USA
    Conf Proc IEEE Eng Med Biol Soc 2011:255-8. 2011
  4. pmc Comparison of low-energy versus high-energy biphasic defibrillation shocks following prolonged ventricular fibrillation
    Gregory P Walcott
    Department of Medicine Division of Cardiovascular Diseases, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA
    Prehosp Emerg Care 14:62-70. 2010
  5. doi request reprint Effect of timing and duration of a single chest compression pause on short-term survival following prolonged ventricular fibrillation
    Gregory P Walcott
    University of Alabama, B140 Volker Hall, 1670 University Blvd, Birmingham, AL 35294, United States
    Resuscitation 80:458-62. 2009
  6. ncbi request reprint Do clinically relevant transthoracic defibrillation energies cause myocardial damage and dysfunction?
    Gregory P Walcott
    Cardiac Rhythm Management Laboratory, Division of Cardiovascular Diseases, Department of Medicine, University of Alabama at Birmingham, Volker Hall B140, 1670 University Blvd, Birmingham, AL 35294, USA
    Resuscitation 59:59-70. 2003
  7. ncbi request reprint Effects of burst stimulation during ventricular fibrillation on cardiac function after defibrillation
    Gregory P Walcott
    Division of Cardiovascular Diseases, Department of Medicine, University of Alabama, 1670 University Blvd, Birmingham, AL 35294, USA
    Am J Physiol Heart Circ Physiol 285:H766-74. 2003
  8. ncbi request reprint Defibrillation with a minimally invasive direct cardiac massage device
    Gregory P Walcott
    University of Alabama at Birmingham, 1530 3rd Ave So, Volker Hall B140, 35294 0019, USA
    Resuscitation 55:301-7. 2002
  9. ncbi request reprint Biphasic waveform external defibrillation thresholds for spontaneous ventricular fibrillation secondary to acute ischemia
    Gregory P Walcott
    Cardiac Rhythm Management Laboratory, Division of Cardiovascular Diseases, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama 35294 0019, USA
    J Am Coll Cardiol 39:359-65. 2002
  10. ncbi request reprint Endocardial wave front organization during ventricular fibrillation in humans
    Gregory P Walcott
    Division of Cardiovascular Diseases, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA
    J Am Coll Cardiol 39:109-15. 2002

Detail Information

Publications37

  1. ncbi request reprint Relative efficacy of monophasic and biphasic waveforms for transthoracic defibrillation after short and long durations of ventricular fibrillation
    G P Walcott
    Division of Cardiovascular Diseases, Department of Medicine, University of Alabama at Birmingham, AL, USA
    Circulation 98:2210-5. 1998
    ..In protocol 2, we compared the efficacy of the more efficacious biphasic waveform from protocol 1, QSBW, with CDSMW after 15 seconds and 5 minutes of fibrillation...
  2. pmc Burst stimulation improves hemodynamics during resuscitation after prolonged ventricular fibrillation
    Gregory Walcott
    University of Alabama at Birmingham, Birmingham, AL, USA
    Circ Arrhythm Electrophysiol 2:57-62. 2009
    ..We hypothesized that a similar series of electrical pulses could increase myocardial function and blood pressure during the early post-resuscitation period...
  3. doi request reprint Ventricular fibrillation threshold of rapid short pulses
    Gregory P Walcott
    Cardiac Rhythm Management Laboratory, University of Alabama, Birmingham, USA
    Conf Proc IEEE Eng Med Biol Soc 2011:255-8. 2011
    ..This also allows for the risk assessment of CEWs by comparison to international electrical safety standards. The output of these weapons appears to be well below the VF risk limits as set by these standards...
  4. pmc Comparison of low-energy versus high-energy biphasic defibrillation shocks following prolonged ventricular fibrillation
    Gregory P Walcott
    Department of Medicine Division of Cardiovascular Diseases, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA
    Prehosp Emerg Care 14:62-70. 2010
    ..This concern has been raised again with the development of the biphasic defibrillator...
  5. doi request reprint Effect of timing and duration of a single chest compression pause on short-term survival following prolonged ventricular fibrillation
    Gregory P Walcott
    University of Alabama, B140 Volker Hall, 1670 University Blvd, Birmingham, AL 35294, United States
    Resuscitation 80:458-62. 2009
    ..Previous animal studies have shown that multiple pauses of increasing duration decrease resuscitation success. We investigated the effect of varying the characteristics of a single pause near defibrillation on resuscitation outcome...
  6. ncbi request reprint Do clinically relevant transthoracic defibrillation energies cause myocardial damage and dysfunction?
    Gregory P Walcott
    Cardiac Rhythm Management Laboratory, Division of Cardiovascular Diseases, Department of Medicine, University of Alabama at Birmingham, Volker Hall B140, 1670 University Blvd, Birmingham, AL 35294, USA
    Resuscitation 59:59-70. 2003
    ..Until those studies are completed, it seems reasonable to use the same 360 J (5 J/kg) energy limit for biphasic shocks as for monophasic shocks...
  7. ncbi request reprint Effects of burst stimulation during ventricular fibrillation on cardiac function after defibrillation
    Gregory P Walcott
    Division of Cardiovascular Diseases, Department of Medicine, University of Alabama, 1670 University Blvd, Birmingham, AL 35294, USA
    Am J Physiol Heart Circ Physiol 285:H766-74. 2003
    ..beta-Blockade or reserpine pretreatment prevents most of this postshock increase in HR, arterial pressure, and LV pressure...
  8. ncbi request reprint Defibrillation with a minimally invasive direct cardiac massage device
    Gregory P Walcott
    University of Alabama at Birmingham, 1530 3rd Ave So, Volker Hall B140, 35294 0019, USA
    Resuscitation 55:301-7. 2002
    ....
  9. ncbi request reprint Biphasic waveform external defibrillation thresholds for spontaneous ventricular fibrillation secondary to acute ischemia
    Gregory P Walcott
    Cardiac Rhythm Management Laboratory, Division of Cardiovascular Diseases, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama 35294 0019, USA
    J Am Coll Cardiol 39:359-65. 2002
    ....
  10. ncbi request reprint Endocardial wave front organization during ventricular fibrillation in humans
    Gregory P Walcott
    Division of Cardiovascular Diseases, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA
    J Am Coll Cardiol 39:109-15. 2002
    ..This study was designed to characterize the organization of ventricular fibrillation (VF) on the endocardium of humans...
  11. ncbi request reprint Atrial defibrillation thresholds of electrode configurations available to an atrioventricular defibrillator
    M E Benser
    Cardiac Rhythm Management Laboratory, Guidant Corporation, St Paul, Minnesota, USA
    J Cardiovasc Electrophysiol 12:957-64. 2001
    ..We also tested the atrial defibrillation thresholds of five other configurations...
  12. ncbi request reprint Pacing during ventricular fibrillation: factors influencing the ability to capture
    J C Newton
    Department of Physiology and Biophysics, University of Alabama at Birmingham, 35294, USA
    J Cardiovasc Electrophysiol 12:76-84. 2001
    ..CONCLUSION: The probability of a pacing train capturing fibrillating myocardium can be influenced by the pacing protocol parameters...
  13. ncbi request reprint A telemetry system for the study of spontaneous cardiac arrhythmias
    D L Rollins
    Department of Medicine, University of Alabama at Birmingham 35294, USA
    IEEE Trans Biomed Eng 47:887-92. 2000
    ..Approximately 12 h of 14,000 bytes/s data can be collected with each set of batteries. The system is suitable for continuous monitoring of animal models of spontaneous arrhythmias and sudden cardiac death...
  14. ncbi request reprint Improvement of defibrillation efficacy and quantification of activation patterns during ventricular fibrillation in a canine heart failure model
    J Huang
    Department of Medicine, University of Alabama at Birmingham, USA
    Circulation 103:1473-8. 2001
    ..CONCLUSIONS: HF increases the DFT. This is partially reversed by an auxiliary shock. HF markedly changes VF activation patterns...
  15. ncbi request reprint Continuous telemetry from a chronic canine model of sudden cardiac death
    C R Killingsworth
    Department of Medicine, University of Alabama at Birmingham, 35294 0019, USA
    J Cardiovasc Electrophysiol 11:1333-41. 2000
    ..We sought to develop a continuously telemetered animal model of sudden cardiac death (SCD) to study the role of existing infarcts and acute ischemia in fatal arrhythmias...
  16. ncbi request reprint Comparison of the temperature profile and pathological effect at unipolar, bipolar and phased radiofrequency current configurations
    X Zheng
    Division of Cardiovascular Diseases, Department of Medicine, University of Alabama at Birmingham, AL 35294, USA
    J Interv Card Electrophysiol 5:401-10. 2001
    ..As judged by tissue temperature, lesion depth and uniformity, and RF power requirement, 127 degrees RF may be a better energy configuration for linear ablation than the other RF modalities tested...
  17. ncbi request reprint The relationship of defibrillation and stimulation: design implications for the optimum defibrillation waveform
    R E Ideker
    Department of Medicine, University of Alabama, Volker Hall B 140A 1670 University Blvd, Birmingham, AL 35292 0019, USA
    Europace 5:245-6. 2003
  18. ncbi request reprint Right atrial septal electrode for reducing the atrial defibrillation threshold
    X Zheng
    Division of Cardiovascular Diseases, Department of Medicine, University of Alabama, Birmingham, USA
    Circulation 104:1066-70. 2001
    ..CONCLUSIONS: The ADFT of the standard RAA-->CS configuration may be markedly reduced with an additional electrode situated at the RSP...
  19. ncbi request reprint Comparison of six clinically used external defibrillators in swine
    Robert G Walker
    Medtronic Physio Control Corporation, 11811 Willows Road NE, 98073 9706, Redmond, WA, USA
    Resuscitation 57:73-83. 2003
    ....
  20. pmc Lifetimes of epicardial rotors in panoramic optical maps of fibrillating swine ventricles
    Matthew W Kay
    Department of Biomedical Engineering, University of Alabama at Birmingham, Birmingham, AL 35294, USA
    Am J Physiol Heart Circ Physiol 291:H1935-41. 2006
    ..This paucity of persistent rotors suggests that individual rotors will eventually terminate by themselves and therefore that the continual formation of new rotors is critical for VF maintenance...
  21. pmc Panoramic optical mapping reveals continuous epicardial reentry during ventricular fibrillation in the isolated swine heart
    Jack M Rogers
    Department of Biomedical Engineering, University of Alabama, Birmingham, Alabama, USA
    Biophys J 92:1090-5. 2007
    ..These data suggest that VF in this model is not driven by localized sources; thus, new anti-VF treatments designed to target such sources may be less effective than global interventions...
  22. ncbi request reprint Porcine defibrillation thresholds with chopped biphasic truncated exponential waveforms
    Joseph L Sullivan
    Medtronic Emergency Response Systems, 11811 Willows Rd NE, P O Box 97006, Redmond, WA 98073 9706, USA
    Resuscitation 74:325-31. 2007
    ..Previous studies comparing chopped and unchopped waveforms have found conflicting results. This study compared the defibrillation thresholds (DFTs) of a variety of chopped and unchopped BTE waveforms...
  23. pmc Chemical ablation of the Purkinje system causes early termination and activation rate slowing of long-duration ventricular fibrillation in dogs
    Derek J Dosdall
    Volker Hall B140, 1670 Univ Blvd, Birmingham, AL 35294 0019, USA
    Am J Physiol Heart Circ Physiol 295:H883-9. 2008
    ..Ablation of the subendocardium hastens VF spontaneous termination and alters VF activation sequences, suggesting that Purkinje fibers are important in the maintenance of LDVF...
  24. ncbi request reprint Reduction of the internal atrial defibrillation threshold with balanced orthogonal sequential shocks
    Xiangsheng Zheng
    J Cardiovasc Electrophysiol 13:904-9. 2002
    ....
  25. ncbi request reprint Impact of myocardial ischemia and reperfusion on ventricular defibrillation patterns, energy requirements, and detection of recovery
    Hao Qin
    Department of Physiology and Biophysics, Medicine, University of Alabama at Birmingham, 35294 0019, USA
    Circulation 105:2537-42. 2002
    ..This could explain why the defibrillation threshold (DFT) for spontaneous VF appears markedly higher than for electrically induced VF...
  26. ncbi request reprint Effect of electrode location in great cardiac vein on the ventricular defibrillation threshold
    Jian Huang
    Departments of Medicine, Biomedical Engineering and Physiology, University of Alabama at Birmingham, Birmingham, Alabama, USA
    Pacing Clin Electrophysiol 25:42-8. 2002
    ..001). Application of an auxiliary shock to the apical region, near the region where previous studies have indicated that the RV primary shock has its weakest effects, caused the greatest decrease in DFT...
  27. ncbi request reprint Chronic myocardial infarction is a substrate for bradycardia-induced spontaneous tachyarrhythmias and sudden death in conscious animals
    Cheryl R Killingsworth
    Cardiac Rhythm Management Laboratory, Division of Cardiovascular Diseases, Department of Medicine, University of Alabama at Birmingham, 35294 0019, USA
    J Cardiovasc Electrophysiol 17:189-97. 2006
    ..We tested the hypothesis that MI and bradycardia cause more spontaneous sustained VT than does bradycardia alone...
  28. ncbi request reprint Evidence that activation following failed defibrillation is not caused by triggered activity
    Xiangsheng Zheng
    Division of Cardiovascular Diseases, Department of Medicine, University of Alabama at Birmingham, Alabama, USA
    J Cardiovasc Electrophysiol 16:1200-5. 2005
    ....
  29. ncbi request reprint Mechanisms for the maintenance of ventricular fibrillation: the nonuniform dispersion of refractoriness, restitution properties, or anatomic heterogeneities?
    Hao Qin
    Department of Medicine, University of Alabama, Birmingham, Alabama 35294, USA
    J Cardiovasc Electrophysiol 16:888-97. 2005
    ..The relative importance of nonuniform dispersion of refractoriness, steep restitution slopes, and anatomic heterogeneities in causing conduction block during ventricular fibrillation (VF) remains unknown...
  30. ncbi request reprint Activation sequences following failed atrial defibrillation
    Xiangsheng Zheng
    Division of Cardiovascular Diseases, Department of Medicine, University of Alabama at Birmingham, 35294, USA
    Heart Rhythm 1:616-23. 2004
    ....
  31. ncbi request reprint Defibrillation threshold and cardiac responses using an external biphasic defibrillator with pediatric and adult adhesive patches in pediatric-sized piglets
    Cheryl R Killingsworth
    Cardiac Rhythm Management Laboratory, Department of Medicine, Division of Cardiovascular Diseases, University of Alabama at Birmingham, 1670 University Boulevard, B140 Volker Hall, Birmingham, AL 35294, USA
    Resuscitation 55:177-85. 2002
    ..These data suggest that there is a substantial safety margin above a DFT strength shock for this biphasic waveform in piglets...
  32. ncbi request reprint Ventricular fibrillation and defibrillation--what are the major unresolved issues?
    Raymond E Ideker
    Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama 35294 0019, USA
    Heart Rhythm 2:555-8. 2005
  33. ncbi request reprint Short-acting beta-adrenergic antagonist esmolol given at reperfusion improves survival after prolonged ventricular fibrillation
    Cheryl R Killingsworth
    Cardiac Rhythm Management Laboratory, Division of Cardiovascular Diseases, Department of Medicine, University of Alabama at Birmingham, AL 35294 0019, USA
    Circulation 109:2469-74. 2004
    ....
  34. ncbi request reprint Emission ratiometry for simultaneous calcium and action potential measurements with coloaded dyes in rabbit hearts: reduction of motion and drift
    Wei Kong
    Department of Biomedical Engineering of the School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599 7575, USA
    J Cardiovasc Electrophysiol 14:76-82. 2003
    ....
  35. ncbi request reprint Identification of transmural necrosis along a linear catheter ablation lesion during atrial fibrillation and sinus rhythm
    Javier E Sanchez
    Department of Internal Medicine, Division of Cardiovascular Diseases, Cardiac Rhythm Management Laboratory, University of Alabama at Birmingham, Birmingham, AL 35294, USA
    J Interv Card Electrophysiol 8:9-17. 2003
    ..We hypothesized that changes in pacing thresholds and electrogram amplitude during atrial fibrillation and sinus rhythm could be used to assess whether a radiofrequency ablation resulted in transmural necrosis...
  36. ncbi request reprint Epicardial organization of human ventricular fibrillation
    Kumaraswamy Nanthakumar
    Division of Cardiovascular Medicine, University of Alabama at Birmingham, 35294, USA
    Heart Rhythm 1:14-23. 2004
    ..The objective of this study was to test the hypothesis that on the epicardium of the in vivo human heart, ventricular fibrillation (VF) consists of chaotic small wavefronts that constantly change paths...
  37. ncbi request reprint Ecclesiastes, cardiac arrest, and the electrocardiogram
    Raymond E Ideker
    Pacing Clin Electrophysiol 28:607-9. 2005