Absence of significant myocardial injury following elective direct current cardioversion for atrial fibrillation.

Background: Direct current (DC) cardioversion is used to terminate cardiac arrhythmias. Current guidelines list cardioversion as a cause of myocardial injury. Objective: This study determined whether external DC cardioversion results in myocardial injury measured by serial changes in high-sensitivity cardiac troponin T (hs-cTnT) and high-sensitivity cardiac troponin I (hs-cTnI). Methods: This was a prospective study of patients undergoing elective external DC cardioversion for atrial fibrillation. hs-cTnT and hs-cTnI were measured precardioversion and at least 6 hours postcardioversion. Myocardial injury was present when there were significant changes in both hs-cTnT and hs-cTnI. Results: Ninety-eight subjects were analyzed. Median cumulative energy delivered was 121.9 (interquartile range [IQR] 102.2-302.7) J. Multiple cases 23 (23.5%) required 300 J or more. Maximum cumulative energy delivered was 2455.1 J. There were small significant changes in both hs-cTnT (median precardioversion 12 [IQR 7-19) ng/L], median postcardioversion 13 [IQR 8-21] ng/L; P < .001) and hs-cTnI (median precardioversion 5 [IQR 3-10) ng/L], median postcardioversion 7 [IQR 3.6-11) ng/L; P < .001). Results were similar in patients with high-energy shocks and did not vary based on precardioversion values. Only 2 (2%) cases met criteria for myocardial injury. Conclusion: DC cardioversion resulted in a small but statistically significant changes in hs-cTnT and hs-cTnI in 2% of patients studied irrespective of shock energy. Patients with marked troponin elevations after elective cardioversion should be assessed for other causes of myocardial injury. It should not be assumed the myocardial injury was from the cardioversion.

Epidemiology of in-hospital cardiac arrest complicating non-ST-segment elevation myocardial infarction receiving early coronary angiography.

In the period between 2000 and 2014, 584,704 admissions with non-ST-segment elevation myocardial infarction that received early coronary angiography (day zero) were identified from the National Inpatient Sample. In-hospital cardiac arrest was noted in 4349 (0.8%), of which ~47% were from ventricular arrhythmias and ~90% of occurred within ≤4 days. Non-ST-segment elevation myocardial infarction admissions with in-hospital cardiac arrest had higher in-hospital mortality compared to those without (61% vs. 1.6%) with an unchanged temporal trend of in-hospital cardiac arrest rates (adjusted odds ratio 1.29 [95% confidence interval 0.73-2.28]) in 2014 compared to 2000).

Early vs. delayed in-hospital cardiac arrest complicating ST-elevation myocardial infarction receiving primary percutaneous coronary intervention.

BACKGROUND: There are limited data on the timing and outcomes of in-hospital cardiac arrest (IHCA) in patients with ST-elevation myocardial infarction (STEMI) receiving primary percutaneous coronary intervention (pPCI). This study sought to examine the in-hospital mortality, temporal trends and resource utilization in early vs. delayed IHCA in STEMI. METHODS: Retrospective cohort study from the National Inpatient Sample of all STEMI admissions during 2000-2014 receiving pPCI on hospital day zero. Admissions transferred from other hospitals, with do-not-resuscitate status, without information on IHCA timing, and receiving surgical revascularization were excluded. IHCA was classified as early (hospital day zero) and delayed (on/after hospital day 1). The primary outcome was in-hospital mortality and secondary outcomes included prevalence, temporal trends, and resource utilization. RESULTS: During this 15-year period, 19,185 admissions met the inclusion criteria, with 15,404 (80%) experiencing an early IHCA. The cohort with delayed IHCA was on average older, female, with higher comorbidity, and greater prevalence of non-shockable rhythms and acute organ failure. There was a temporal increase in early IHCA (adjusted odds ratio [aOR] 1.67 [95% confidence interval {CI} 1.35-2.08]) and a decrease in delayed IHCA (aOR 0.60 [95% CI 0.48-0.74]) in 2014 compared to 2000. Compared to the early IHCA cohort, the delayed IHCA cohort had higher in-hospital mortality (aOR 5.35 [95% CI 4.83-5.94]), higher hospitalization costs ($115,165 ± 109,848 vs. 139,038 ± 142,745) and less frequent discharges to home (74% vs. 52%). CONCLUSIONS: Delayed IHCA (on or after hospital day 1) was associated with higher in-hospital mortality and resource utilization compared to early IHCA.

Direct Current Cardioversion of Atrial Arrhythmias in Adults With Cardiac Amyloidosis.

BACKGROUND: Arrhythmias, conduction abnormalities, and intracardiac thrombus are common in patients with cardiac amyloidosis (CA). Outcomes of direct-current cardioversion (DCCV) for atrial arrhythmias in patients with CA are unknown. OBJECTIVES: This study sought to examine DCCV procedural outcomes in patients with CA. METHODS: Patients with CA scheduled for DCCV for atrial arrhythmias from January 2000 through December 2012 were identified and matched 2:1 with control patients by age, sex, type of atrial arrhythmia, and date of DCCV. RESULTS: CA patients (n = 58, mean age 69 ± 9 years, 81% male) were included. CA patients had a significantly higher cardioversion cancellation rate (28% vs. 7%; p < 0.001) compared with control patients, mainly due to intracardiac thrombus identified on transesophageal echocardiogram (13 of 16 [81%] vs. 2 of 8 [25%]; p = 0.02); 4 of 13 of the CA patients (31%) with intracardiac thrombus on transesophageal echocardiogram received adequate anticoagulation ≥3 weeks and another 2 of 13 (15%) had arrhythmia duration <48 h. DCCV success rate (90% vs. 94%; p = 0.4) was not different. Procedural complications were more frequent in CA versus control patients (6 of 42 [14%] vs. 2 of 106 [2%]; p = 0.007); complications in CA included ventricular arrhythmias in 2 and severe bradyarrhythmias requiring pacemaker implantation in 2. The only complication in the control group was self-limited bradyarrhythmias. CONCLUSIONS: Patients with CA undergoing DCCV had a significantly high cancellation rate mainly due to a high incidence of intracardiac thrombus even among patients who received adequate anticoagulation. Although the success rate of restoring sinus rhythm was high, tachyarrhythmias and bradyarrhythmias complicating DCCV were significantly more frequent in CA patients compared with control patients.

Echocardiographic left ventricular diastolic dysfunction predicts hospital mortality after out-of-hospital cardiac arrest.

PURPOSE: To determine whether systolic or diastolic dysfunction on transthoracic echocardiogram (TTE) predicts mortality after out-of-hospital cardiac arrest (OHCA). METHODS: Retrospective cohort study of 173 OHCA subjects undergoing targeted temperature management who underwent TTE during hospitalization. Univariate analysis and multivariate logistic regression were used to determine associations between TTE measurements of systolic and diastolic function and systemic hemodynamics with all-cause mortality. RESULTS: Mean age was 61.6 ±â€¯12.4 years (72.7% male) and initial rhythm was shockable in 89%. Hospital mortality was 30.6%. Mean LVEF was 40% and was not different in hospital survivors (p = 0.81). TTE parameters reflecting systolic function and systemic hemodynamics did not predict hospital mortality. Medial mitral E/e' ratio was associated with hospital mortality, with an optimal cut-off > 13 (p = 0.002). After multivariate adjustment, medial mitral E/e' ratio remained predictive of hospital mortality (OR 1.11, 95% CI 1.03-1.20, p = 0.004). Subjects with a medial mitral E/e' ratio > 13 had higher mortality during long-term follow-up (p < 0.001 by log-rank). CONCLUSIONS: Diastolic dysfunction (higher medial mitral E/e' ratio) on TTE independently predicted mortality after OHCA; systolic dysfunction and TTE hemodynamic parameters did not. This reflects a novel use of Doppler TTE to predict outcomes after OHCA.

Changes in left ventricular systolic and diastolic function on serial echocardiography after out-of-hospital cardiac arrest.

AIM: Reversible myocardial dysfunction is common after out-of-hospital cardiac arrest (OHCA). The aim of this study was to determine if changes on serial transthoracic echocardiography (TTE) can predict long-term mortality in OHCA subjects. METHODS: This is a single-center historical cohort study of OHCA subjects undergoing targeted temperature management who received >1 TTE during hospitalization. Two-dimensional and Doppler parameters of systolic and diastolic function were compared between paired TTE. Univariate analysis was used to determine associations between TTE parameters and all-cause mortality. RESULTS: Fifty-nine patients were included; mean age was 59.4 ±â€¯11.2 years (75% male). Initial rhythm was shockable in 90%. Initial TTE was done a median of 10.4 h after admission and repeat TTE was done 5.7 ±â€¯4.1 days later. Between TTE studies, there were significant increases in left ventricular ejection fraction (LVEF, from 32% to 43%), cardiac output, stroke volume, and other Doppler-derived hemodynamic parameters, while systemic vascular resistance decreased (all p < 0.001). Systolic function and hemodynamic parameters on initial TTE were not associated with follow-up mortality. Patients who died during follow-up (n = 16, 27%) had smaller increases in LVEF and cardiac output-derived hemodynamic parameters than long-term survivors (p < 0.05). CONCLUSIONS: Significant changes in systolic function and hemodynamic parameters occur on serial Doppler TTE after OHCA, consistent with reversible post-arrest myocardial dysfunction. The magnitude of those changes is greater in long-term survivors, emphasizing that the degree of recovery from post-arrest myocardial dysfunction may be more important than its initial severity.

Improving trend in ventricular fibrillation/pulseless ventricular tachycardia out-of-hospital cardiac arrest in Rochester, Minnesota: A 26-year observational study from 1991 to 2016.

BACKGROUND: Mortality from out-of-hospital cardiac arrest (OHCA) is characterized by substantial regional variation. The Institute of Medicine (IOM) recently recommended enhancing the capabilities of EMS systems to improve outcome. In this study, we analyzed the trend in outcome from ventricular fibrillation/pulseless ventricular tachycardia (VF/pVT) OHCA in Rochester, MN. Survival from these forms of arrest is commonly employed as a benchmark of Emergency Medical Services (EMS) system performance. METHODS: Using a population-based Utstein-style registry in Rochester, MN where a first responder early defibrillation system is utilized, we evaluated outcome from all EMS-treated VF/pVT arrests and the subgroup of bystander-witnessed VF/pVT from 1991 to 2016. Outcome measurement was neurologically intact survival to discharge, defined as Cerebral Performance Category (CPC) 1 or 2. We divided the 26-year study into three periods: 1991-1997, 1998-2008, and 2009-2016, based on initiation of the first responder system of police officers in 1991 and fire-rescue personnel in 1998, and the latter period for comparison with our previous report in 2009. RESULTS: We observed 355 all VF/pVT arrests and 292 bystander-witnessed VF/pVT arrests between 1991 and 2016. In 2009-2016, neurologically intact survival to discharge from overall VF/pVT and bystander-witnessed VF/pVT increased to 53.7% and 65.2%, respectively, compared with 39.5% and 43.4% in 1991-1997. Using multivariable analysis, survival significantly increased in 2009-2016 among all VF/pVT arrests (adjusted OR, 3.10; 95% CI, 1.54-6.40) and bystander-witnessed VF/pVT (adjusted OR, 4.28; 95% CI, 2.01-9.50), compared with those in 1991-1997. CONCLUSIONS: We observed a significant improving secular trend in neurologically intact survival from VF/pVT cardiac arrests with a relatively high recent survival rate in this EMS System.

Electroencephalography Predicts Poor and Good Outcomes After Cardiac Arrest: A Two-Center Study.

OBJECTIVE: The prognostic role of electroencephalography during and after targeted temperature management in postcardiac arrest patients, relatively to other predictors, is incompletely known. We assessed performances of electroencephalography during and after targeted temperature management toward good and poor outcomes, along with other recognized predictors. DESIGN: Cohort study (April 2009 to March 2016). SETTING: Two academic hospitals (Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland; Mayo Clinic, Rochester, MN). PATIENTS: Consecutive comatose adults admitted after cardiac arrest, identified through prospective registries. INTERVENTIONS: All patients were managed with targeted temperature management, receiving prespecified standardized clinical, neurophysiologic (particularly, electroencephalography during and after targeted temperature management), and biochemical evaluations. MEASUREMENTS AND MAIN RESULTS: We assessed electroencephalography variables (reactivity, continuity, epileptiform features, and prespecified "benign" or "highly malignant" patterns based on the American Clinical Neurophysiology Society nomenclature) and other clinical, neurophysiologic (somatosensory-evoked potential), and biochemical prognosticators. Good outcome (Cerebral Performance Categories 1 and 2) and mortality predictions at 3 months were calculated. Among 357 patients, early electroencephalography reactivity and continuity and flexor or better motor reaction had greater than 70% positive predictive value for good outcome; reactivity (80.4%; 95% CI, 75.9-84.4%) and motor response (80.1%; 95% CI, 75.6-84.1%) had highest accuracy. Early benign electroencephalography heralded good outcome in 86.2% (95% CI, 79.8-91.1%). False positive rates for mortality were less than 5% for epileptiform or nonreactive early electroencephalography, nonreactive late electroencephalography, absent somatosensory-evoked potential, absent pupillary or corneal reflexes, presence of myoclonus, and neuron-specific enolase greater than 75 µg/L; accuracy was highest for early electroencephalography reactivity (86.6%; 95% CI, 82.6-90.0). Early highly malignant electroencephalography had an false positive rate of 1.5% with accuracy of 85.7% (95% CI, 81.7-89.2%). CONCLUSIONS: This study provides class III evidence that electroencephalography reactivity predicts both poor and good outcomes, and motor reaction good outcome after cardiac arrest. Electroencephalography reactivity seems to be the best discriminator between good and poor outcomes. Standardized electroencephalography interpretation seems to predict both conditions during and after targeted temperature management.

A Comparison of Chest Compression Quality Delivered During On-Scene and Ground Transport Cardiopulmonary Resuscitation.

INTRODUCTION: 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. METHODS: 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 transport data for each patient; paired proportions were compared with the nonparametric Wilcoxon signed rank test. RESULTS: In the pre-feedback period, we analyzed 105 of 140 paired cases (75.0%); in the post-feedback period, 35 of 140 paired cases (25.0%) were analyzed. The proportion of correct depths during on-scene compressions (median, 41.9%; interquartile range [IQR], 16.1-73.1) was higher compared to the paired transport proportion (median, 8.7%; IQR, 2.7-48.9). Proportions of on-scene median correct rates and transport median correct depths did not improve in the post-feedback period. CONCLUSION: Transport chest compressions are significantly worse than on-scene compressions. Implementation of visual real-time feedback did not affect performance.

Improving Survival From Cardiac Arrest: A Review of Contemporary Practice and Challenges.

Cardiac arrest is a common and lethal condition frequently encountered by emergency medicine providers. Resuscitation of persons after cardiac arrest remains challenging, and outcomes remain poor overall. Successful resuscitation hinges on timely, high-quality cardiopulmonary resuscitation. The optimal method of providing chest compressions and ventilator support during cardiac arrest remains uncertain. Prompt and effective defibrillation of ventricular arrhythmias is one of the few effective therapies available for treatment of cardiac arrest. Despite numerous studies during several decades, no specific drug delivered during cardiac arrest has been shown to improve neurologically intact survival after cardiac arrest. Extracorporeal circulation can rescue a minority of highly selected patients with refractory cardiac arrest. Current management of pulseless electrical activity is associated with poor outcomes, but it is hoped that a more targeted diagnostic approach based on electrocardiography and bedside cardiac ultrasonography may improve survival. The evolution of postresuscitation care appears to have improved cardiac arrest outcomes in patients who are successfully resuscitated. The initial approach to early stabilization includes standard measures, such as support of pulmonary function, hemodynamic stabilization, and rapid diagnostic assessment. Coronary angiography is often indicated because of the high frequency of unstable coronary artery disease in comatose survivors of cardiac arrest and should be performed early after resuscitation. Optimizing and standardizing our current approach to cardiac arrest resuscitation and postresuscitation care will be essential for developing strategies for improving survival after cardiac arrest.

Left Atrial Appendage Patency at Cardioversion After Surgical Left Atrial Appendage Intervention.

BACKGROUND: 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. METHODS: 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. RESULTS: 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 34 patients (47%) with incomplete closure of LAA. The strongest risk factor for thrombus was a patent, partially closed LAA (odds ratio 4.36, p = 0.003). Systemically accessible thrombus was present in 19 of the 93 patients (20%), and cardioversion was cancelled owing to thrombus in 15 (16%). CONCLUSIONS: Surgical closure of the LAA is often incomplete. Interrogation of the residual LAA after surgical LAA intervention with TEE before DCCV frequently detects thrombus and alters clinical management. Patients undergoing DCCV after surgical LAA intervention require evaluation with TEE for LAA patency and thrombus.

Heparin dose adjustment required to maintain goal-activated partial thromboplastin time during therapeutic hypothermia.

PURPOSE: The impact of therapeutic hypothermia (TH) on unfractionated heparin (UFH) management is essentially unknown. The aim of this study was to evaluate the effect of TH on UFH dosing and activated partial thromboplastin (aPTT) response. MATERIALS AND METHODS: Consecutive patients treated from 2005 to 2011 who received intravenous UFH via a dosing nomogram during TH were included. First, heparin doses and aPTT responses were compared between 2 core temperature groups, less than or equal to 33°C and greater than 35°C. Next, the first aPTT, drawn at 6 hours for temperature less than or equal to 33°C, was assessed. Lastly, a linear model was developed to predict the mean aPTT, based on temperatures and heparin doses. RESULTS: Of the 156 TH patients, 68 were included. At temperatures less than or equal to 33°C, 76.3% of all aPTT levels and 81.0% of the first aPTTs were above goal range, respectively. Using a linear model, an UFH dose of 12 U/kg per hour predicts an aPTT of 134 seconds at less than or equal to 33°C. CONCLUSIONS: Using guideline-recommended heparin dosing without dose adjustment for temperature changes produced excessive aPTT during the cooling phase for TH patients. Reduction in the UFH dose of 43% to 54% may be required during TH. We recommend frequent aPTT monitoring during the cooling and rewarming phases to attain a desired aPTT range.

Implantable cardioverter-defibrillator therapy in patients with ventricular fibrillation out of hospital cardiac arrest secondary to acute coronary syndrome.

BACKGROUND: Survivors of ventricular fibrillation out of hospital cardiac arrest (VF-OHCA) due to a potentially reversible cause such as acute myocardial infarction (MI) or ischemia are considered to be at low risk of recurrent arrhythmia. Implantable cardioverter defibrillators (ICD) are not routinely recommended in such patients. However, the outcome of these patients in the era of rapid coronary revascularization and ICD therapy is not known. METHODS AND RESULTS: We examined the outcome of 114 consecutive survivors of VF OHCA due to acute MI or ischemia in Olmsted County, MN from 1990 to 2011. An ICD was implanted in 45/114 patients. ICD recipients had lower EF [median (IQR) 38 (26 to 54) versus 48 (35 to 58) %, P=0.04]. During a median (IQR) follow-up of 9.9 (4.4 to 14.6) years, ICD implantation was associated with reduced cardiac mortality (HR 0.24 [0.07 to 0.88], P=0.031) and a trend towards reduced all-cause mortality (HR 0.56 [0.30 to 1.02], P=0.059) after adjusting for the first principal component. One or more appropriate ICD therapies were delivered in 19/45, with half of the patients receiving therapy within 1 year. Patients with EF ≤35% at discharge continued to be at long-term risk for ICD therapy compared with those with EF >35% who were at increased risk predominantly in the first 8 months. EF and revascularization were not significantly associated with ICD therapy in the multivariable analysis. CONCLUSIONS: Patients with VF-OHCA in the setting of acute MI or myocardial ischemia remain at high risk of recurrent ventricular arrhythmias, particularly if EF ≤35%. This suggests that ICD implantation may be reasonable if EF ≤35%.

Diastolic function and new-onset atrial fibrillation following cardiac surgery.

BACKGROUND: 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. METHODS: 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. RESULTS: Of 223 patients, 91 (40.8%) experienced new-onset POAF. Univariate predictors of POAF included increasing age, male gender, operations involving mitral valve repair/replacement, nonsmoking, hypertension, increased intraoperative pulmonary artery pressure, grade I diastolic dysfunction, abnormal diastolic function of any grade, decreased medial e', elevated medial E/e', and increased left atrial volume. Multivariate predictors of POAF included increasing age, increased left atrial volume, and elevated initial intraoperative pulmonary artery pressure. Even after exclusion of patients with hypertrophic obstructive cardiomyopathy or those undergoing mitral valve operations, diastolic dysfunction was not a multivariate predictor of POAF. CONCLUSIONS: In the patient population studied here, preoperative diastolic dysfunction was not predictive of POAF. In addition to increasing age, initial intraoperative pulmonary artery systolic pressure and left atrial volume were both significant multivariate predictors of POAF.

Recurrent ventricular fibrillation: experience with first responders prior to advanced life support interventions.

AIM: Following defibrillation, ventricular fibrillation (VF) frequently recurs during out-of-hospital cardiac arrest (OHCA). Prior studies have reported conflicting results regarding its association with survival. The aim of this study was to examine the impact of recurrent VF in the presence of first responders before advanced life support (ALS) interventions. METHODS: Electrocardiographic data from first responder automated external defibrillators (AEDs) were analyzed. A successful shock was defined as termination of VF for 5s or longer. Recurrent VF was defined as any VF that occurred after a successful shock. The primary outcome was neurologically intact survival to hospital discharge (CPC 1-2). RESULTS: 108 patients within our emergency system experienced a witnessed VF arrest. Of these, 73 (68%) had at least one recurrence of VF. Median time to recurrence of VF was 25s [interquartile range (IQR) 11-66s]. Median time in recurrent VF was 180s (IQR 105-266s). Survival was observed in 25 (71%) of patients with no recurrent VF and in 36 (49%) who had recurrence. Recurrent VF was associated with a lower odds of survival on univariate analysis (OR 0.39, 95% CI 0.16-0.92, p=0.0325). After adjusting for bystander CPR, gender and age, recurrent VF had a similar direction of effect but was no longer significantly associated with neurologically intact survival (OR 0.44, 95% CI 0.17-1.11, p=0.081). CONCLUSIONS: In the presence of first responders, VF recurred in 68% of patients. Recurrent VF was associated with a lower odds of survival, though its prognostic significance appeared to be blunted when considered in light of confounding variables. Recurrent VF may have significant survival implications, and further studies to assess its prognostic significance should be performed.