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    Roger White

    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.... 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...
    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... 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...
    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... 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...
    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... 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...
    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... 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.
    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... 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...
    Surgical left atrial appendage (LAA) closure is often incomplete, with patients frequently requiring direct current cardioversion (DCCV) for atrial arrhythmias. Transesophageal echocardiography (TEE) is often performed before DCCV to... more
    Surgical left atrial appendage (LAA) closure is often incomplete, with patients frequently requiring direct current cardioversion (DCCV) for atrial arrhythmias. Transesophageal echocardiography (TEE) is often performed before DCCV to exclude LAA thrombus. The impact of incomplete surgical LAA closure on patients referred for postoperative DCCV is unknown. We retrospectively reviewed patients undergoing TEE-guided DCCV within 30 days of cardiac surgery and surgical LAA closure. All pre-DCCV TEEs were reviewed to assess LAA patency and the presence of thrombus. Ninety-three patients (mean age 68 years; 61 men [66%]) had a median time from surgery to DCCV of 6 days. Duration of atrial fibrillation was 48 hours or more in 85% (n = 79). On pre-DCCV TEE, a residual communication from the LAA was noted in 37% (n = 34). The rate of LAA patency was higher after suture closure than after surgical excision or staple closure. Thrombus was present in 26 of the 93 patients (28%), including 16 of ...
    American Heart Association (AHA) guidelines recommend cardiopulmonary resuscitation (CPR) chest compressions 1.5 to 2 inches (3.75-5 cm) deep at 100 to 120 per minute. Recent studies demonstrated that manual CPR by emergency medical... more
    American Heart Association (AHA) guidelines recommend cardiopulmonary resuscitation (CPR) chest compressions 1.5 to 2 inches (3.75-5 cm) deep at 100 to 120 per minute. Recent studies demonstrated that manual CPR by emergency medical services (EMS) personnel is substandard. We hypothesized that transport CPR quality is significantly worse than on-scene CPR quality. We analyzed adult patients receiving on-scene and transport chest compressions from nine EMS sites across Minnesota and Wisconsin from May 2008 to July 2010. Two periods were analyzed: before and after visual feedback. CPR data were collected and exported with the Zoll M series monitor and a sternally placed accelerometer measuring chest compression rate and depth. We compared compression data with 2010 AHA guidelines and Zoll RescueNet Code Review software. CPR depth and rate were "above (deep)," "in," or "below (shallow)" the target range according to AHA guidelines. We paired on-scene and t...
    Background: Survival following out-of-hospital cardiac arrest (OHCA) from ventricular fibrillation (VF) is poor and dependent on a rapid emergency response system. Improvements in emergent early response have resulted in a higher... more
    Background: Survival following out-of-hospital cardiac arrest (OHCA) from ventricular fibrillation (VF) is poor and dependent on a rapid emergency response system. Improvements in emergent early response have resulted in a higher percentage of patients surviving to admission. However, the admission variables that predict both short- and long-term survival in a region with high discharge survival following OHCA require further study in order to identify survivors at subsequent highest risk. Methods: All patients with OHCA arrest in Olmsted County Minnesota between 1990 and 2000 who received defibrillation of VF by emergency services were included in the population-based study. Baseline patient admission characteristics in survivor and nonsurvivor groups were compared. Survivors to hospital discharge were prospectively followed to determine long-term survival. Results: Two hundred patients suffered a VF arrest. Of these patients, 145 (73%) survived to hospital admission (7 died within...
    Primary systemic amyloidosis (AL) is a well-recognized systemic disease, and cardiac amyloidosis accounts for 10% of all nonischemic cardiomyopathies [J S C Med Assoc 97 (2001) 201-206]. The median survival of patients with symptomatic... more
    Primary systemic amyloidosis (AL) is a well-recognized systemic disease, and cardiac amyloidosis accounts for 10% of all nonischemic cardiomyopathies [J S C Med Assoc 97 (2001) 201-206]. The median survival of patients with symptomatic congestive heart failure secondary to cardiac amyloidosis is 4 months [New Engl J Med 336 (1997) 1202-1207; Am J Med 100 (1996) 290-298]. The cause of death in most patients is refractory congestive heart failure or sudden arrhythmic [Mayo Clin Proc 59 (1984) 589-597]. While there are reports of in-hospital arrhythmic deaths in these patients, there are no detailed reports that describe the presentation and management of patients with cardiac amyloidosis who have experienced an out-of-hospital cardiac arrest (OHCA). We describe here our experience with four patients with AL who had an OHCA, including presenting rhythms, interventions, and outcomes.
    The potential impact of efforts to improve the chain of survival for out-of-hospital sudden cardiac arrest (SCA) is unclear in part because estimates of the incidence of treatable cases of SCA are uncertain. The aim of the investigation... more
    The potential impact of efforts to improve the chain of survival for out-of-hospital sudden cardiac arrest (SCA) is unclear in part because estimates of the incidence of treatable cases of SCA are uncertain. The aim of the investigation was to determine a representative national incidence of emergency medical services (EMS)-treated all-rhythm and ventricular fibrillation (VF) SCA as well as survival. We used Medline to identify peer-reviewed articles published between 1 January 1980 and 31 March 2003 that reported a US community's EMS SCA experience. Inclusion criteria required the study to include at least 25 cases, report the total number of all-rhythm and/or ventricular fibrillation arrests, and provide information about population size and study duration. Incidence was computed by dividing the total number of SCA events by the product of the community's population and the study duration. Reports from 35 communities met the inclusion criteria. A total of 35,801 all-rhythm EMS-treated cardiac arrests occurred during 62.11 million person-years of observation resulting in an overall incidence of 54.99 per 100,000 person-years. The incidence of ventricular fibrillation-rhythm SCA was 21.32 per 100,000 person-years. Sensitivity analyses generally produced similar results. Applying these results to the US population, 155,000 persons would experience EMS-treated all-rhythm SCA and 60,000 persons would experience EMS-treated ventricular fibrillation-rhythm SCA annually in the US. Survival was 8.4% for all-rhythm and 17.7% for ventricular fibrillation SCA. The results provide a framework to assess opportunities and limitations of EMS care with regard to the public health burden of SCA.
    To assess outcome in patients with ventricular fibrillation (VF) treated by defibrillator-equipped police and emergency medical technician-paramedics in an advanced life support (ALS) emergency medical services (EMS) system. We carried... more
    To assess outcome in patients with ventricular fibrillation (VF) treated by defibrillator-equipped police and emergency medical technician-paramedics in an advanced life support (ALS) emergency medical services (EMS) system. We carried out a retrospective observational outcome study of all consecutive adult patients with atraumatic cardiac arrest treated from November 1990 through July 1995. The study was carried out in a city with a population of 76,865 in an area of 32.6 square miles. Central 911 dispatched police and an ALS ambulance simultaneously. Accurate intervals were obtained with the synchronization of all defibrillator clocks with the 911 dispatch clock. The personnel who arrived first delivered the initial shock. After shocks delivered by police, paramedics provided additional treatment if needed. Main outcome measures were time elapsed before delivery of the first shock, restoration of spontaneous circulation (ROSC), and survival to discharge home. Of 84 patients, 31 (37%) were first shocked by police. Thirteen of the 31 demonstrated ROSC, without need for ALS treatment. All 13 survived to discharge. The other 18 patients required ALS; 5 (27.7%) survived. Among the 53 patients first shocked by paramedics, 15 had ROSC after shocks only, and 14 survived. The other 38 needed ALS treatment; 9 survived. Call-to-shock time for all patients was less in the police group than in the paramedic group (5.6 versus 6.3 minutes, P = .038). For all patients, call-to-shock time was less in those with ROSC after shocks only than in those who needed ALS (5.4 versus 6.3 minutes, P = .011). Survival to discharge was 49% (41 of 84), with 18 of 31 (58%) in the police group and 23 of 53 (43%) in the paramedic group. Call-to-shock time for survivors was 5.8 minutes; it was 6.4 minutes for the nonsurvivors (P = .020). Neither ROSC nor discharge survival was significantly different between police and paramedic-shocked patients. ROSC after initial shock and call-to-shock time were major determinants of survival, whether the first shocks were administered by police or by paramedics. With ROSC after shocks only, 27 of 28 (96%) survived, whereas 14 of 56 (25%) needing ALS survived (P < .001). A high discharge-to-home survival rate was obtained with early defibrillation by both police and paramedics. When shocks resulted in ROSC, the overwhelming majority of patients survived (96%). Even brief time decreases (eg. 1 minute) in call-to-shock time increase the likelihood of ROSC from shocks only, with a consequent decrease in the need for ALS intervention. Short call-to-shock time and ROSC response to shocks only are major determinants of a high rate of survival after VF.
    ... Beth Mancini, RN, MSNII Joseph P. Ornato, MD¶ Mary Ann Peberdy, MD¶ Linda Quan, MD# Wanchun Tang, MD** Sergio Timerman, MD ... on evidence showing that a low-energy (150-J), impedance-compensating, biphasic truncated exponential (BTE)... more
    ... Beth Mancini, RN, MSNII Joseph P. Ornato, MD¶ Mary Ann Peberdy, MD¶ Linda Quan, MD# Wanchun Tang, MD** Sergio Timerman, MD ... on evidence showing that a low-energy (150-J), impedance-compensating, biphasic truncated exponential (BTE) waveform is safe and as ...
    Ventricular fibrillation (VF) is treated optimally with a defibrillation shock shortly after patient collapse, but may benefit from initial cardiopulmonary resuscitation (CPR) if the shock is delayed. An objective measure of potential... more
    Ventricular fibrillation (VF) is treated optimally with a defibrillation shock shortly after patient collapse, but may benefit from initial cardiopulmonary resuscitation (CPR) if the shock is delayed. An objective measure of potential responsiveness to defibrillation could help decide optimal initial therapy. a new electrocardiogram (ECG) analysis algorithm was compared with response interval (call-to-shock) for prediction of patient outcome in a population of 87 VF patients in the Rochester, Minnesota area. In a retrospective analysis, both call-to-shock interval (p = 0.009) and ECG analysis (p < 0.001) predicted neurologically intact survival, with ECG analysis the stronger predictor (p = 0.034). When applied to advising initial patient treatment, ECG analysis compared favorably with the call-to-shock interval. Using a 7 min call-to-shock time criterion, 69% of patients would receive shocks first treatment using ECG analysis versus 67% using the call-to-shock interval (p = NS), 94% of survivors would retain successful shocks first treatment versus 85% (p = NS), and 48% of non-survivors receive alternate CPR-first treatment versus 45% (p = NS). Similarly, no significant differences were observed between ECG analysis and call-to-shock interval using an 8 min criterion. Both call-to-shock interval and a real-time ECG analysis are predictive of patient outcome. The ECG analysis is more predictive of neurologically intact survival. Moreover, the ECG analysis is dependent only upon the patient's condition at the time of treatment, with no need for knowledge of the response interval, which may be difficult to estimate at the time of treatment.
    ... Beth Mancini, RN, MSNII Joseph P. Ornato, MD¶ Mary Ann Peberdy, MD¶ Linda Quan, MD# Wanchun Tang, MD** Sergio Timerman, MD ... on evidence showing that a low-energy (150-J), impedance-compensating, biphasic truncated exponential (BTE)... more
    ... Beth Mancini, RN, MSNII Joseph P. Ornato, MD¶ Mary Ann Peberdy, MD¶ Linda Quan, MD# Wanchun Tang, MD** Sergio Timerman, MD ... on evidence showing that a low-energy (150-J), impedance-compensating, biphasic truncated exponential (BTE) waveform is safe and as ...