Roger White - Academia.edu (original) (raw)

Papers by Roger White

European Heart Journal, 2020

Background and introduction Cardioversion is commonly used to terminate cardiac arrhythmias. Some... more Background and introduction Cardioversion is commonly used to terminate cardiac arrhythmias. Some previous reports have suggested that cardioversion results in myocardial injury as evidenced by increased levels of cardiac troponin. However, many of these studies were done years ago with less sensitive troponin assays and monophasic waveform defibrillators. Purpose To determine if external direct current (DC) cardioversion with biphasic rectilinear waveform shocks results in myocardial injury as assessed by high sensitivity cardiac troponin T (hs-cTnT) and I (hs-cTnI). Methods Patients scheduled for elective DC cardioversion for atrial fibrillation or atrial flutter were recruited. Plasma samples for measurement of hs-cTnT and hs-cTnI were obtained pre-cardioversion and as late as feasible but at least 6 hours post-cardioversion [median of 9 (7–11) hours]. Results A total of 96 patients were recruited. One patient was excluded because the pre-cardioversion sample was hemolysed. Media...

Mayo Clinic Proceedings, 2019

Chemistry and physics of lipids, Jan 2, 2016

Ischemic injury is associated with acute myocardial infarction, percutaneous coronary interventio... more Ischemic injury is associated with acute myocardial infarction, percutaneous coronary intervention, coronary artery bypass grafting and open heart surgery. The timely re-establishment of blood flow is critical in order to minimize cardiac complications. Reperfusion after a prolonged ischemic period, however, can induce severe cardiomyocyte dysfunction with mitochondria serving as a major target of ischemia/reperfusion (I/R) injury. An increase in the formation of reactive oxygen species (ROS) induces damage to mitochondrial respiratory complexes leading to uncoupling of oxidative phosphorylation. Mitochondrial membrane perturbations also contribute to calcium overload, opening of the mitochondrial permeability transition pore (mPTP) and the release of apoptotic mediators into the cytoplasm. Clinical and experimental studies show that ischemic preconditioning (ICPRE) and postconditioning (ICPOST) attenuate mitochondrial injury and improve cardiac function in the context of I/R injury...

Circulation, Jan 3, 2015

Bedside cardiac and noncardiac ultrasound are frequently used as diagnostic and prognostic tools ... more Bedside cardiac and noncardiac ultrasound are frequently used as diagnostic and prognostic tools for critically ill patients. 44 Ultrasound may be applied to patients receiving CPR to help assess myocardial contractility and to help identify potentially treatable causes of cardiac arrest such as hypovolemia, pneumothorax, pulmonary thromboembolism, or pericardial tamponade. 45 However, it is unclear whether important clinical outcomes are affected by the routine use of ultrasound among patients experiencing cardiac arrest.

Journal of clinical & experimental cardiology, Jan 22, 2011

AIMS: Cardiac dysfunction is a complication of sepsis and contributes to morbidity and mortality.... more AIMS: Cardiac dysfunction is a complication of sepsis and contributes to morbidity and mortality. Since raising plasma apolipoprotein (apo) A-I and high density lipoprotein (HDL) concentration reduces sepsis complications, we tested the hypothesis that the apoA-I mimetic peptide 4F confers similar protective effects in rats treated with lipopolysaccharide (LPS). METHODS AND RESULTS: Male Sprague-Dawley (SD) rats were randomized to receive saline vehicle (n=13), LPS (10 mg/kg: n=16) or LPS plus 4F (10 mg/kg each: n=13) by intraperitoneal injection. Plasma cytokine and chemokine levels were significantly elevated 24 hrs after LPS administration. Echocardiographic studies revealed changes in cardiac dimensions that resulted in a reduction in left ventricular end-diastolic volume (LVEDV), stroke volume (SV) and cardiac output (CO) 24 hrs after LPS administration. 4F treatment reduced plasma levels of inflammatory mediators and increased LV filling, resulting in improved cardiac performa...

Annals of cardiac anaesthesia

Numerous studies have reported predictors of new-onset postoperative atrial fibrillation (POAF) f... more Numerous studies have reported predictors of new-onset postoperative atrial fibrillation (POAF) following cardiac surgery, which is associated with increased length of stay, cost of care, morbidity, and mortality. The purpose of this study was to examine the association between preoperative diastolic function and occurrence of new-onset POAF in patients undergoing a variety of cardiac surgeries at a single institution. Using data from a prospective study from November 2007 to January 2010, a retrospective review was conducted. The diastolic function of each patient was determined from preoperative transthoracic echocardiograms. Occurrence of new-onset POAF was prospectively noted for each patient in the original study. Demographic and operative characteristics of the study population were analyzed to determine predictors of POAF. Of 223 patients, 91 (40.8%) experienced new-onset POAF. Univariate predictors of POAF included increasing age, male gender, operations involving mitral val...

Neurology, 2013

Objective: We aimed to study the long-term cognitive abilities of patients surviving out-of-hospi... more Objective: We aimed to study the long-term cognitive abilities of patients surviving out-of-hospital cardiac arrest who were treated with therapeutic hypothermia (TH). Methods: We prospectively identified and examined consecutive survivors of out-of-hospital cardiac arrest who underwent TH at our institution from June 2006 to May 2011. The results of brain imaging, serum neuron-specific enolase (NSE) measurements, and EEGs were recorded. We assessed cognitive domains using the modified Telephone Interview for Cognitive Status. An education-adjusted score of $32 was considered normal. Results: Of 133 total patients, 77 (58%) were alive at a median follow-up of 20 months (interquartile range 14-24 months). We interviewed 56 patients (73% of those alive). Median age was 67 years (range 24-88 years). Fifty-one patients (91%) were living independently. Modified Telephone Interview for Cognitive Status scores ranged from 16 to 41. Thirty-three (60%) were considered cognitively normal and 22 (40%) were cognitively impaired. The time to assessment did not differ among the cognitive outcomes (p 5 0.557). The median duration of coma was 2 days, possibly indicating that patients with severe anoxic injury were not included. Eighteen patients were not working at the time of their cardiac arrest (17 were retired and 1 was unemployed). Of the 38 patients who were working up to the time of the cardiac arrest, 30 (79%) returned to work. Cognitive outcome was not associated with age, time to return of spontaneous circulation, brain atrophy, or leukoaraiosis. Conclusions: The majority of surviving patients who underwent TH after cardiac arrest in this series had preserved cognitive function and were able to return to work. Neurology â 2013;81:40-45 GLOSSARY CPC 5 Cerebral Performance Category; IQR 5 interquartile range; NSE 5 neuron-specific enolase; OHCA 5 out-of-hospital cardiac arrest; ROSC 5 return of spontaneous circulation; TH 5 therapeutic hypothermia; TICS-m 5 Telephone Interview for Cognitive Status, modified.

Mayo Clinic Proceedings, 2005

Coronary heart disease is the most common cause of death in the United States, with ventricular f... more Coronary heart disease is the most common cause of death in the United States, with ventricular fibrillation (VF) the most common initial rhythm when cardiac disease causes arrest. Survival after VF out-of-hospital cardiac arrest (OHCA) depends on a sequence of events called the chain of survival, which includes rapid access to emergency medical services, cardiopulmonary resuscitation, defibrillation, and advanced care. Because of widespread implementation of defibrillation programs, more patients survive VF OHCAs, making subsequent care of these patients important. Early hospitalization must focus on potential neurologic injury and therapy targeted at the underlying cardiac disease and antiarrhythmic therapy for long-term secondary prevention of sudden death. Attention to certain cohorts who are at high risk despite their underlying disease, such as women and elderly patients, is necessary. These cohorts may have the greatest response to short-term and long-term therapies for cardiac rehabilitation. With these approaches, long-term survival and quality of life after VF OHCA are favorable. Broadening the focus of the chain of survival to include in-hospital and long-term care will further improve favorable outcomes achieved in an early defibrillation program.

Mayo Clinic Proceedings, 2005

The Journal of Thoracic and Cardiovascular Surgery, 2012

Objective: Ventricular fibrillation occurs commonly after aortic crossclamping in patients underg... more Objective: Ventricular fibrillation occurs commonly after aortic crossclamping in patients undergoing cardiac surgery. Ventricular fibrillation increases myocardial oxygen consumption, and defibrillation may harm the myocardium. Thus, a pharmacologic approach to decreasing the incidence of ventricular fibrillation or the number of shocks required may be beneficial. The goal of this study was to evaluate whether amiodarone or lidocaine was superior to placebo for the prevention of ventricular fibrillation after aortic crossclamping in patients undergoing a variety of cardiac surgical procedures. Methods: Patients undergoing cardiac surgery requiring aortic crossclamping were randomized to receive lidocaine 1.5 mg/kg, amiodarone 300 mg, or placebo before aortic crossclamp removal The primary outcomes were the incidence of ventricular fibrillation and the number of shocks required to terminate ventricular fibrillation. Results: A total of 342 patients completed the trial. On multivariate analysis, there was no difference in the incidence of ventricular fibrillation among treatment groups. The number of required shocks was categorized as 0, 1 to 3, and greater than 3. On multivariate analysis, patients receiving amiodarone required fewer shocks to terminate ventricular fibrillation (odds ratio, 0.51; 95% confidence interval, 0.31-0.83; P ¼ .008 vs placebo). There was no difference between lidocaine and placebo in the number of required shocks (odds ratio, 0.86; 95% confidence interval, 0.52-1.41; P ¼ .541). Conclusions: In patients undergoing a variety of cardiac surgical procedures, neither amiodarone nor lidocaine reduced the incidence of ventricular fibrillation. Amiodarone decreased the number of shocks required to terminate ventricular fibrillation.

Circulation, 2007

We read with interest the article by Stiell and colleagues 1 in which the efficacy of defibrillat... more We read with interest the article by Stiell and colleagues 1 in which the efficacy of defibrillation with fixed low energy was compared with escalating high-energy biphasic waveforms in out-of-hospital cardiac arrest settings. When patients received multiple shocks, the likelihood of converting ventricular fibrillation was reportedly greater with high-energy escalating shocks. The study addresses important issues. However, the devices that were compared did not take into consideration differences in waveforms and, most especially, the time duration of the currents delivered. The comparisons were made with the commercially available biphasic waveform device that delivers escalating shocks marketed by the sponsor. The fixed 150-J shocks also were delivered with the Medtronic LIFEPAK 500 modified to deliver 150-J shocks using the same capacitor, substantially reducing the current delivered to below the manufacturer's recommended minimal dose of 200 J. Because it is the current delivered over a defined time rather than the energy itself that is the predominant determinant of successful defibrillation, the comparisons are not valid. More specifically, the Medtronic LIFEPAK 500, modified to deliver 150-J shocks, used a 200-F capacitor. The only commercially available devices that use a fixed 150-J energy protocol are those manufactured by Philips Medical Systems, which uses a 100-F capacitor. Consequently, we have computed that the current was reduced substantially (Ͼ25%) and the likelihood of defibrillation accordingly. Moreover, higher delivered energies with waveforms that minimize currents produce greater postresuscitation myocardial dysfunction and worse outcomes. 2 Comparison of "commonly used [automatic external defibrillator] energy dosing regimens" would therefore require a comparison of the Philips design at 150 J with the Medtronic design at 200 to 300 to 360 J to take into account the overriding role of waveforms and especially peak currents.

Anesthesiology, 2005

Long QT syndrome is a malfunction of cardiac ion channels resulting in impaired ventricular repol... more Long QT syndrome is a malfunction of cardiac ion channels resulting in impaired ventricular repolarization that can lead to a characteristic polymorphic ventricular tachycardia known as torsades de pointes. Stressors, by increasing sympathetic tone, and drugs can provoke torsade de pointes, leading to syncope, seizures, or sudden cardiac death in these patients. Beta blockade, implantation of cardioverter defibrillators, and left cardiac sympathetic denervation are used in the treatment of these patients. However, these treatment modalities do not guarantee the prevention of sudden cardiac death. Certain drugs, including anesthetic agents, are known to contribute to QT prolongation. After reviewing the literature the authors give recommendations for the anesthetic management of these patients in the perioperative period.

American Journal of Preventive Medicine, 2006

Markov chain analysis, including sensitivity analysis, was used with a hypothetical population re... more Markov chain analysis, including sensitivity analysis, was used with a hypothetical population resembling that of Olmsted County, MN, aged 30 to 84 in the year 2000 to compare the estimated impact of three interventions to prevent sudden death: 1) Raising blood levels of omega-3 fatty acids. 2) Distributing automated external defibrillators (AEDs). 3) Implanting cardioverter defibrillators (ICDs) in appropriate candidates. Results Raising median omega-3 fatty acid levels would be expected to lower total mortality by 6.4% (range 1.6% to 10.3%). Distributing automated external defibrillators would be expected to lower total mortality by 0.8% (0.2% to 1.3%).

American Journal of Physiology-Heart and Circulatory Physiology, 2009

Systemic inflammation induces a multiple organ dysfunction syndrome that contributes to morbidity... more Systemic inflammation induces a multiple organ dysfunction syndrome that contributes to morbidity and mortality in septic patients. Since increasing plasma apolipoprotein A-I (apoA-I) and HDL may reduce the complications of sepsis, we tested the hypothesis that the apoA-I mimetic peptide 4F confers similar protective effects in rats undergoing cecal ligation and puncture (CLP) injury. Male Sprague-Dawley rats were randomized to undergo CLP or sham surgery. IL-6 levels were significantly elevated in plasma by 6 h after CLP surgery compared with shams. In subsequent studies, CLP rats were further subdivided to receive vehicle or 4F (10 mg/kg) by intraperitoneal injection, 6 h after sepsis induction. Sham-operated rats received saline. Echocardiographic studies showed a reduction in left ventricular end-diastolic volume, stroke volume, and cardiac output (CO) 24 h after CLP surgery. These changes were associated with reduced blood volume and left ventricular filling pressure. 4F treatm...

American Heart Journal, 2005

Background Transthoracic cardioversion fails to restore sinus rhythm in 6% to 33% of patients wit... more Background Transthoracic cardioversion fails to restore sinus rhythm in 6% to 33% of patients with atrial fibrillation. This study sought to determine the relative efficacy of biphasic waveforms compared with monophasic waveforms in the treatment of atrial arrhythmias. Methods A total of 912 patients underwent 1022 transthoracic cardioversions between May 2000 and December 2001. A monophasic damped sine waveform was used in the first 304 cases, and a rectilinear biphasic defibrillator was used in the next 718 cases. Results Use of a biphasic waveform was associated with 94% success in conversion to sinus rhythm compared with 84% with a monophasic waveform (P b .001). The cumulative energy required to restore sinus rhythm was lower with biphasic shocks in both atrial fibrillation and atrial flutter groups (554 F 413 J for monophasic vs 199 F 216 J for biphasic shocks in the atrial fibrillation group, P b .001; 251 F 302 J vs 108 F 184 J, respectively, in the atrial flutter group, P b .001). In a multivariate analysis, use of a biphasic shock was associated with a 3.9-fold increase in success of cardioversion. Conclusion When used to cardiovert atrial arrhythmias, the rectilinear biphasic waveform was associated with higher success rates and lower cumulative energies than the monophasic damped sine waveform.

Circulation, 2010

This chapter presents guidelines for defibrillation with manual defibrillators and automated exte... more This chapter presents guidelines for defibrillation with manual defibrillators and automated external defibrillators (AEDs), synchronized cardioversion, and pacing. AEDs may be used by lay rescuers and healthcare providers as part of basic life support. Manual defibrillation, cardioversion, and pacing are advanced life support therapies.

Circulation, 2010

A dvanced cardiovascular life support (ACLS) impacts multiple key links in the chain of survival ... more A dvanced cardiovascular life support (ACLS) impacts multiple key links in the chain of survival that include interventions to prevent cardiac arrest, treat cardiac arrest, and improve outcomes of patients who achieve return of spontaneous circulation (ROSC) after cardiac arrest. ACLS interventions aimed at preventing cardiac arrest include airway management, ventilation support, and treatment of bradyarrhythmias and tachyarrhythmias. For the treatment of cardiac arrest, ACLS interventions build on the basic life support (BLS) foundation of immediate recognition and activation of the emergency response system, early CPR, and rapid defibrillation to further increase the likelihood of ROSC with drug therapy, advanced airway management, and physiologic monitoring. Following ROSC, survival and neurologic outcome can be improved with integrated post-cardiac arrest care.

Neurocritical Care, 2010

Background Prognostication for survivors of cardiac arrest is a frequent challenge to neurologist... more Background Prognostication for survivors of cardiac arrest is a frequent challenge to neurologists. Our aim was to determine whether the FOUR (Full Outline of UnResponsiveness) score is an accurate predictor of outcome in patients after cardiac arrest and to compare its performance to the Glasgow Coma Scale (GCS). Methods We prospectively identified patients surviving cardiac arrest from June 2006 to October 2009. Neurologic exams were grouped into two time intervals following cardiac arrest: 1-2 days and 3-5 days. The FOUR score and the Glasgow coma scale (GCS) were determined for each examination. Primary outcome was in-hospital mortality. Results Of 136 patients, 112 (82%) were examined on days 1-2 after cardiac arrest and 87 (64%) on days 3-5. Forty-seven patients (35%) survived to hospital discharge and 89 (65%) died during hospitalization. No patients with a sum FOUR score B4 at exam days 3-5 survived (false positive rate [FPR] 0% C.I. 0.000-0.0345), whereas one patient (2%) with sum GCS score of 3 survived to discharge (FPR 2.2%, C.I. <0.0001-0.1758). At days 3-5 after arrest, 41 of 45 (91%) patients with a sum FOUR score >8 survived (P < 0.0001), while 39 of 45 (87%) with a sum GCS > 6 survived (P < 0.0001). A 2-point improvement in FOUR score, but not GCS, in serial exams was associated with survival. Sensitivities, specificities, positive, and negative predictive values were comparable between both scales. Conclusion The FOUR score, a simple clinical tool, is an accurate predictor of outcome in patients surviving cardiac arrest.

European Heart Journal, 2020

Background and introduction Cardioversion is commonly used to terminate cardiac arrhythmias. Some... more Background and introduction Cardioversion is commonly used to terminate cardiac arrhythmias. Some previous reports have suggested that cardioversion results in myocardial injury as evidenced by increased levels of cardiac troponin. However, many of these studies were done years ago with less sensitive troponin assays and monophasic waveform defibrillators. Purpose To determine if external direct current (DC) cardioversion with biphasic rectilinear waveform shocks results in myocardial injury as assessed by high sensitivity cardiac troponin T (hs-cTnT) and I (hs-cTnI). Methods Patients scheduled for elective DC cardioversion for atrial fibrillation or atrial flutter were recruited. Plasma samples for measurement of hs-cTnT and hs-cTnI were obtained pre-cardioversion and as late as feasible but at least 6 hours post-cardioversion [median of 9 (7–11) hours]. Results A total of 96 patients were recruited. One patient was excluded because the pre-cardioversion sample was hemolysed. Media...

Mayo Clinic Proceedings, 2019

Chemistry and physics of lipids, Jan 2, 2016

Ischemic injury is associated with acute myocardial infarction, percutaneous coronary interventio... more Ischemic injury is associated with acute myocardial infarction, percutaneous coronary intervention, coronary artery bypass grafting and open heart surgery. The timely re-establishment of blood flow is critical in order to minimize cardiac complications. Reperfusion after a prolonged ischemic period, however, can induce severe cardiomyocyte dysfunction with mitochondria serving as a major target of ischemia/reperfusion (I/R) injury. An increase in the formation of reactive oxygen species (ROS) induces damage to mitochondrial respiratory complexes leading to uncoupling of oxidative phosphorylation. Mitochondrial membrane perturbations also contribute to calcium overload, opening of the mitochondrial permeability transition pore (mPTP) and the release of apoptotic mediators into the cytoplasm. Clinical and experimental studies show that ischemic preconditioning (ICPRE) and postconditioning (ICPOST) attenuate mitochondrial injury and improve cardiac function in the context of I/R injury...

Circulation, Jan 3, 2015

Bedside cardiac and noncardiac ultrasound are frequently used as diagnostic and prognostic tools ... more Bedside cardiac and noncardiac ultrasound are frequently used as diagnostic and prognostic tools for critically ill patients. 44 Ultrasound may be applied to patients receiving CPR to help assess myocardial contractility and to help identify potentially treatable causes of cardiac arrest such as hypovolemia, pneumothorax, pulmonary thromboembolism, or pericardial tamponade. 45 However, it is unclear whether important clinical outcomes are affected by the routine use of ultrasound among patients experiencing cardiac arrest.

Journal of clinical & experimental cardiology, Jan 22, 2011

AIMS: Cardiac dysfunction is a complication of sepsis and contributes to morbidity and mortality.... more AIMS: Cardiac dysfunction is a complication of sepsis and contributes to morbidity and mortality. Since raising plasma apolipoprotein (apo) A-I and high density lipoprotein (HDL) concentration reduces sepsis complications, we tested the hypothesis that the apoA-I mimetic peptide 4F confers similar protective effects in rats treated with lipopolysaccharide (LPS). METHODS AND RESULTS: Male Sprague-Dawley (SD) rats were randomized to receive saline vehicle (n=13), LPS (10 mg/kg: n=16) or LPS plus 4F (10 mg/kg each: n=13) by intraperitoneal injection. Plasma cytokine and chemokine levels were significantly elevated 24 hrs after LPS administration. Echocardiographic studies revealed changes in cardiac dimensions that resulted in a reduction in left ventricular end-diastolic volume (LVEDV), stroke volume (SV) and cardiac output (CO) 24 hrs after LPS administration. 4F treatment reduced plasma levels of inflammatory mediators and increased LV filling, resulting in improved cardiac performa...

Annals of cardiac anaesthesia

Numerous studies have reported predictors of new-onset postoperative atrial fibrillation (POAF) f... more Numerous studies have reported predictors of new-onset postoperative atrial fibrillation (POAF) following cardiac surgery, which is associated with increased length of stay, cost of care, morbidity, and mortality. The purpose of this study was to examine the association between preoperative diastolic function and occurrence of new-onset POAF in patients undergoing a variety of cardiac surgeries at a single institution. Using data from a prospective study from November 2007 to January 2010, a retrospective review was conducted. The diastolic function of each patient was determined from preoperative transthoracic echocardiograms. Occurrence of new-onset POAF was prospectively noted for each patient in the original study. Demographic and operative characteristics of the study population were analyzed to determine predictors of POAF. Of 223 patients, 91 (40.8%) experienced new-onset POAF. Univariate predictors of POAF included increasing age, male gender, operations involving mitral val...

Neurology, 2013

Objective: We aimed to study the long-term cognitive abilities of patients surviving out-of-hospi... more Objective: We aimed to study the long-term cognitive abilities of patients surviving out-of-hospital cardiac arrest who were treated with therapeutic hypothermia (TH). Methods: We prospectively identified and examined consecutive survivors of out-of-hospital cardiac arrest who underwent TH at our institution from June 2006 to May 2011. The results of brain imaging, serum neuron-specific enolase (NSE) measurements, and EEGs were recorded. We assessed cognitive domains using the modified Telephone Interview for Cognitive Status. An education-adjusted score of $32 was considered normal. Results: Of 133 total patients, 77 (58%) were alive at a median follow-up of 20 months (interquartile range 14-24 months). We interviewed 56 patients (73% of those alive). Median age was 67 years (range 24-88 years). Fifty-one patients (91%) were living independently. Modified Telephone Interview for Cognitive Status scores ranged from 16 to 41. Thirty-three (60%) were considered cognitively normal and 22 (40%) were cognitively impaired. The time to assessment did not differ among the cognitive outcomes (p 5 0.557). The median duration of coma was 2 days, possibly indicating that patients with severe anoxic injury were not included. Eighteen patients were not working at the time of their cardiac arrest (17 were retired and 1 was unemployed). Of the 38 patients who were working up to the time of the cardiac arrest, 30 (79%) returned to work. Cognitive outcome was not associated with age, time to return of spontaneous circulation, brain atrophy, or leukoaraiosis. Conclusions: The majority of surviving patients who underwent TH after cardiac arrest in this series had preserved cognitive function and were able to return to work. Neurology â 2013;81:40-45 GLOSSARY CPC 5 Cerebral Performance Category; IQR 5 interquartile range; NSE 5 neuron-specific enolase; OHCA 5 out-of-hospital cardiac arrest; ROSC 5 return of spontaneous circulation; TH 5 therapeutic hypothermia; TICS-m 5 Telephone Interview for Cognitive Status, modified.

Mayo Clinic Proceedings, 2005

Coronary heart disease is the most common cause of death in the United States, with ventricular f... more Coronary heart disease is the most common cause of death in the United States, with ventricular fibrillation (VF) the most common initial rhythm when cardiac disease causes arrest. Survival after VF out-of-hospital cardiac arrest (OHCA) depends on a sequence of events called the chain of survival, which includes rapid access to emergency medical services, cardiopulmonary resuscitation, defibrillation, and advanced care. Because of widespread implementation of defibrillation programs, more patients survive VF OHCAs, making subsequent care of these patients important. Early hospitalization must focus on potential neurologic injury and therapy targeted at the underlying cardiac disease and antiarrhythmic therapy for long-term secondary prevention of sudden death. Attention to certain cohorts who are at high risk despite their underlying disease, such as women and elderly patients, is necessary. These cohorts may have the greatest response to short-term and long-term therapies for cardiac rehabilitation. With these approaches, long-term survival and quality of life after VF OHCA are favorable. Broadening the focus of the chain of survival to include in-hospital and long-term care will further improve favorable outcomes achieved in an early defibrillation program.

Mayo Clinic Proceedings, 2005

The Journal of Thoracic and Cardiovascular Surgery, 2012

Objective: Ventricular fibrillation occurs commonly after aortic crossclamping in patients underg... more Objective: Ventricular fibrillation occurs commonly after aortic crossclamping in patients undergoing cardiac surgery. Ventricular fibrillation increases myocardial oxygen consumption, and defibrillation may harm the myocardium. Thus, a pharmacologic approach to decreasing the incidence of ventricular fibrillation or the number of shocks required may be beneficial. The goal of this study was to evaluate whether amiodarone or lidocaine was superior to placebo for the prevention of ventricular fibrillation after aortic crossclamping in patients undergoing a variety of cardiac surgical procedures. Methods: Patients undergoing cardiac surgery requiring aortic crossclamping were randomized to receive lidocaine 1.5 mg/kg, amiodarone 300 mg, or placebo before aortic crossclamp removal The primary outcomes were the incidence of ventricular fibrillation and the number of shocks required to terminate ventricular fibrillation. Results: A total of 342 patients completed the trial. On multivariate analysis, there was no difference in the incidence of ventricular fibrillation among treatment groups. The number of required shocks was categorized as 0, 1 to 3, and greater than 3. On multivariate analysis, patients receiving amiodarone required fewer shocks to terminate ventricular fibrillation (odds ratio, 0.51; 95% confidence interval, 0.31-0.83; P ¼ .008 vs placebo). There was no difference between lidocaine and placebo in the number of required shocks (odds ratio, 0.86; 95% confidence interval, 0.52-1.41; P ¼ .541). Conclusions: In patients undergoing a variety of cardiac surgical procedures, neither amiodarone nor lidocaine reduced the incidence of ventricular fibrillation. Amiodarone decreased the number of shocks required to terminate ventricular fibrillation.

Circulation, 2007

We read with interest the article by Stiell and colleagues 1 in which the efficacy of defibrillat... more We read with interest the article by Stiell and colleagues 1 in which the efficacy of defibrillation with fixed low energy was compared with escalating high-energy biphasic waveforms in out-of-hospital cardiac arrest settings. When patients received multiple shocks, the likelihood of converting ventricular fibrillation was reportedly greater with high-energy escalating shocks. The study addresses important issues. However, the devices that were compared did not take into consideration differences in waveforms and, most especially, the time duration of the currents delivered. The comparisons were made with the commercially available biphasic waveform device that delivers escalating shocks marketed by the sponsor. The fixed 150-J shocks also were delivered with the Medtronic LIFEPAK 500 modified to deliver 150-J shocks using the same capacitor, substantially reducing the current delivered to below the manufacturer's recommended minimal dose of 200 J. Because it is the current delivered over a defined time rather than the energy itself that is the predominant determinant of successful defibrillation, the comparisons are not valid. More specifically, the Medtronic LIFEPAK 500, modified to deliver 150-J shocks, used a 200-F capacitor. The only commercially available devices that use a fixed 150-J energy protocol are those manufactured by Philips Medical Systems, which uses a 100-F capacitor. Consequently, we have computed that the current was reduced substantially (Ͼ25%) and the likelihood of defibrillation accordingly. Moreover, higher delivered energies with waveforms that minimize currents produce greater postresuscitation myocardial dysfunction and worse outcomes. 2 Comparison of "commonly used [automatic external defibrillator] energy dosing regimens" would therefore require a comparison of the Philips design at 150 J with the Medtronic design at 200 to 300 to 360 J to take into account the overriding role of waveforms and especially peak currents.

Anesthesiology, 2005

Long QT syndrome is a malfunction of cardiac ion channels resulting in impaired ventricular repol... more Long QT syndrome is a malfunction of cardiac ion channels resulting in impaired ventricular repolarization that can lead to a characteristic polymorphic ventricular tachycardia known as torsades de pointes. Stressors, by increasing sympathetic tone, and drugs can provoke torsade de pointes, leading to syncope, seizures, or sudden cardiac death in these patients. Beta blockade, implantation of cardioverter defibrillators, and left cardiac sympathetic denervation are used in the treatment of these patients. However, these treatment modalities do not guarantee the prevention of sudden cardiac death. Certain drugs, including anesthetic agents, are known to contribute to QT prolongation. After reviewing the literature the authors give recommendations for the anesthetic management of these patients in the perioperative period.

American Journal of Preventive Medicine, 2006

Markov chain analysis, including sensitivity analysis, was used with a hypothetical population re... more Markov chain analysis, including sensitivity analysis, was used with a hypothetical population resembling that of Olmsted County, MN, aged 30 to 84 in the year 2000 to compare the estimated impact of three interventions to prevent sudden death: 1) Raising blood levels of omega-3 fatty acids. 2) Distributing automated external defibrillators (AEDs). 3) Implanting cardioverter defibrillators (ICDs) in appropriate candidates. Results Raising median omega-3 fatty acid levels would be expected to lower total mortality by 6.4% (range 1.6% to 10.3%). Distributing automated external defibrillators would be expected to lower total mortality by 0.8% (0.2% to 1.3%).

American Journal of Physiology-Heart and Circulatory Physiology, 2009

Systemic inflammation induces a multiple organ dysfunction syndrome that contributes to morbidity... more Systemic inflammation induces a multiple organ dysfunction syndrome that contributes to morbidity and mortality in septic patients. Since increasing plasma apolipoprotein A-I (apoA-I) and HDL may reduce the complications of sepsis, we tested the hypothesis that the apoA-I mimetic peptide 4F confers similar protective effects in rats undergoing cecal ligation and puncture (CLP) injury. Male Sprague-Dawley rats were randomized to undergo CLP or sham surgery. IL-6 levels were significantly elevated in plasma by 6 h after CLP surgery compared with shams. In subsequent studies, CLP rats were further subdivided to receive vehicle or 4F (10 mg/kg) by intraperitoneal injection, 6 h after sepsis induction. Sham-operated rats received saline. Echocardiographic studies showed a reduction in left ventricular end-diastolic volume, stroke volume, and cardiac output (CO) 24 h after CLP surgery. These changes were associated with reduced blood volume and left ventricular filling pressure. 4F treatm...

American Heart Journal, 2005

Background Transthoracic cardioversion fails to restore sinus rhythm in 6% to 33% of patients wit... more Background Transthoracic cardioversion fails to restore sinus rhythm in 6% to 33% of patients with atrial fibrillation. This study sought to determine the relative efficacy of biphasic waveforms compared with monophasic waveforms in the treatment of atrial arrhythmias. Methods A total of 912 patients underwent 1022 transthoracic cardioversions between May 2000 and December 2001. A monophasic damped sine waveform was used in the first 304 cases, and a rectilinear biphasic defibrillator was used in the next 718 cases. Results Use of a biphasic waveform was associated with 94% success in conversion to sinus rhythm compared with 84% with a monophasic waveform (P b .001). The cumulative energy required to restore sinus rhythm was lower with biphasic shocks in both atrial fibrillation and atrial flutter groups (554 F 413 J for monophasic vs 199 F 216 J for biphasic shocks in the atrial fibrillation group, P b .001; 251 F 302 J vs 108 F 184 J, respectively, in the atrial flutter group, P b .001). In a multivariate analysis, use of a biphasic shock was associated with a 3.9-fold increase in success of cardioversion. Conclusion When used to cardiovert atrial arrhythmias, the rectilinear biphasic waveform was associated with higher success rates and lower cumulative energies than the monophasic damped sine waveform.

Circulation, 2010

This chapter presents guidelines for defibrillation with manual defibrillators and automated exte... more This chapter presents guidelines for defibrillation with manual defibrillators and automated external defibrillators (AEDs), synchronized cardioversion, and pacing. AEDs may be used by lay rescuers and healthcare providers as part of basic life support. Manual defibrillation, cardioversion, and pacing are advanced life support therapies.

Circulation, 2010

A dvanced cardiovascular life support (ACLS) impacts multiple key links in the chain of survival ... more A dvanced cardiovascular life support (ACLS) impacts multiple key links in the chain of survival that include interventions to prevent cardiac arrest, treat cardiac arrest, and improve outcomes of patients who achieve return of spontaneous circulation (ROSC) after cardiac arrest. ACLS interventions aimed at preventing cardiac arrest include airway management, ventilation support, and treatment of bradyarrhythmias and tachyarrhythmias. For the treatment of cardiac arrest, ACLS interventions build on the basic life support (BLS) foundation of immediate recognition and activation of the emergency response system, early CPR, and rapid defibrillation to further increase the likelihood of ROSC with drug therapy, advanced airway management, and physiologic monitoring. Following ROSC, survival and neurologic outcome can be improved with integrated post-cardiac arrest care.

Neurocritical Care, 2010

Background Prognostication for survivors of cardiac arrest is a frequent challenge to neurologist... more Background Prognostication for survivors of cardiac arrest is a frequent challenge to neurologists. Our aim was to determine whether the FOUR (Full Outline of UnResponsiveness) score is an accurate predictor of outcome in patients after cardiac arrest and to compare its performance to the Glasgow Coma Scale (GCS). Methods We prospectively identified patients surviving cardiac arrest from June 2006 to October 2009. Neurologic exams were grouped into two time intervals following cardiac arrest: 1-2 days and 3-5 days. The FOUR score and the Glasgow coma scale (GCS) were determined for each examination. Primary outcome was in-hospital mortality. Results Of 136 patients, 112 (82%) were examined on days 1-2 after cardiac arrest and 87 (64%) on days 3-5. Forty-seven patients (35%) survived to hospital discharge and 89 (65%) died during hospitalization. No patients with a sum FOUR score B4 at exam days 3-5 survived (false positive rate [FPR] 0% C.I. 0.000-0.0345), whereas one patient (2%) with sum GCS score of 3 survived to discharge (FPR 2.2%, C.I. <0.0001-0.1758). At days 3-5 after arrest, 41 of 45 (91%) patients with a sum FOUR score >8 survived (P < 0.0001), while 39 of 45 (87%) with a sum GCS > 6 survived (P < 0.0001). A 2-point improvement in FOUR score, but not GCS, in serial exams was associated with survival. Sensitivities, specificities, positive, and negative predictive values were comparable between both scales. Conclusion The FOUR score, a simple clinical tool, is an accurate predictor of outcome in patients surviving cardiac arrest.