Epidemiology of SARS-CoV-2 antibodies among firefighters/paramedics of a US fire department: a cross-sectional study.

OBJECTIVES: We estimate the point seroprevalence of SARS-CoV-2 antibodies in the frontline firefighter/paramedic workforce of a South Florida fire department located in the epicentre of a State outbreak. METHODS: A cross-sectional study design was used to estimate the point seroprevalence of SARS-CoV-2 antibodies using a rapid immunoglobulin (Ig)M-IgG combined point-of-care lateral flow immunoassay among frontline firefighters/paramedics collected over a 2-day period, 16-17 April 2020. Fire department personnel were emailed a survey link assessing COVID-19 symptoms and work exposures the day prior to the scheduled drive-through antibody testing at a designated fire station. Off-duty and on-duty firefighter/paramedic personnel drove through the fire station/training facility in their personal vehicles or on-duty engine/rescue trucks for SARS-CoV-2 antibody testing. RESULTS: Among the 203 firefighters/paramedics that make up the fire department workforce, 18 firefighters/paramedics (8.9%) tested positive for SARS-CoV-2 antibodies, of which 8 firefighters/paramedics (3.9%) were IgG positive only, 8 (3.9%) were IgM positive only and 2 (0.1%) were IgG/IgM positive. The positive predictive value (PPV) of the serological test is estimated to be 33.2% and the negative predictive value is 99.3%. The average number of COVID-19 case contacts (ie, within 6 feet of an infected person (laboratory-confirmed or probable COVID-19 patient) for ≥15 min) experienced by firefighters/paramedics was higher for those with positive serology compared with those with negative (13.3 cases vs 7.31 cases; p=0.022). None of the antibody positive firefighters/paramedics reported receipt of the annual influenza vaccine compared with firefighters/paramedics who tested negative for SARS-CoV-2 antibodies (0.0% vs 21.0%; p=0.027). CONCLUSION: Rapid SARS-CoV-2 IgM-IgG antibody testing documented early-stage and late-stage infection in a firefighter workforce providing insight to a broader medical surveillance project on return to work for firefighters/paramedics. Given the relatively low PPV of the serological test used in this study back in April 2020, caution should be used in interpreting test results.

Differences in scar lesion formation between radiofrequency and cryoballoon in atrial fibrillation ablation: a comparison study using ultra-high-density mapping.

AIMS: Atrial fibrillation (AF) recurrence after pulmonary vein isolation (PVI) is usually associated to conduction gaps in pulmonary veins (PVs). Our objective was to characterize gaps in patients with recurrences after a first radiofrequency (RF) or cryoballoon (CB) PVI procedure, using a high-density mapping (HDM) system. METHODS AND RESULTS: Fifty patients with AF recurrence after a first PVI procedure (pre-RF 25 patients; pre-CB 25 patients) were included at two centres. Activation map (AM) and voltage map (VM) of the left atrium and PVs were built using the HDM Rhythmia® system. Superior PVs were reconnected more frequently in both groups. Right PVs were reconnected more frequently in pre-RF patients. Pre-RF patients had more reconnected veins than pre-CB patients (mean ± standard deviation: 3.00 ± 0.96 vs. 1.88 ± 1.13; P < 0.001) and more gaps (4.84 ± 2.06 vs. 2.16 ± 1.49; P < 0.001). Gaps in the VM were wider in pre-CB patients (16.5 ± 9.5 mm vs. 12.1 ± 4.8 mm; P = 0.006). There was a gap in 179 of the 800 PV segments analysed (22%); 52% were identified in both AM and VM maps; 39% only in the AM and 8% only in the VM. The highest sensitivity and specificity for gap detection was obtained with VM in pre-CB patients and with AM in pre-RF patients. CONCLUSION: In conclusion, HDM seems to be a useful and precise tool to detect conduction gaps after a first PVI procedure. The anatomical pattern and location of gaps depends on the technique used previously, usually being multiple, smaller, and better detected by AM after RF, and fewer, wider, and better detected by VM after CB.

Identification of cavotricuspid isthmus voltage patterns in typical atrial flutter ablation.

Background: Electroanatomical mapping is an essential tool in the ablation of typical AFL. Objectives: To identify the existence of voltage patterns in the CTI voltage maps and their relevance for typical AFL ablation. Methods: A voltage map of the CTI was made prior to ablation, identifying the areas of maximum voltage and their location along the CTI, allowing classification into patterns according to their distribution. A stepwise ablation approach targeting the areas of maximum voltage was conducted. The ablation characteristics were compared based on the pattern obtained. Results: Two voltage patterns were identified, with differences in ablation time to bidirectional CTI block. No complications occurred. Conclusions: Voltage mapping identifies patterns in the CTI with implications for typical AFL ablation.

Cardiac magnetic resonance outperforms echocardiography to predict subsequent implantable cardioverter defibrillator therapies in ST-segment elevation myocardial infarction patients.

Background: Implantable cardioverter defibrillators (ICD) are effective as a primary prevention measure of ventricular tachyarrhythmias in patients with ST-segment elevation myocardial infarction (STEMI) and depressed left ventricular ejection fraction (LVEF). The implications of using cardiac magnetic resonance (CMR) instead of echocardiography (Echo) to assess LVEF prior to the indication of ICD in this setting are unknown. Materials and methods: We evaluated 52 STEMI patients (56.6 ± 11 years, 88.5% male) treated with ICD in primary prevention who underwent echocardiography and CMR prior to ICD implantation. ICD implantation was indicated based on the presence of heart failure and depressed LVEF (≤ 35%) by echocardiography, CMR, or both. Prediction of ICD therapies (ICD-T) during follow-up by echocardiography and CMR before ICD implantation was assessed. Results: Compared to echocardiography, LVEF was lower by cardiac CMR (30.2 ± 9% vs. 37.4 ± 7.6%, p < 0.001). LVEF ≤ 35% was detected in 24 patients (46.2%) by Echo and in 42 (80.7%) by CMR. During a mean follow-up of 6.1 ± 4.2 years, 10 patients received appropriate ICD-T (3.16 ICD-T per 100 person-years): 5 direct shocks to treat very fast ventricular tachycardia or ventricular fibrillation, 3 effective antitachycardia pacing (ATP) for treatment of ventricular tachycardia, and 2 ineffective ATP followed by shock to treat ventricular tachycardia. Echo-LVEF ≤ 35% correctly predicted ICD-T in 4/10 (40%) patients and CMR-LVEF ≤ 35% in 10/10 (100%) patients. CMR-LVEF improved on Echo-LVEF for predicting ICD-T (area under the curve: 0.76 vs. 0.48, p = 0.04). Conclusion: In STEMI patients treated with ICD, assessment of LVEF by CMR outperforms Echo-LVEF to predict the subsequent use of appropriate ICD therapies.

Simulation-based education improves military trainees' skill performance and self-confidence in tourniquet placement: A randomized controlled trial.

BACKGROUND: Tactical Combat Casualty Care (TCCC) is the standard of care for stabilization and treatment of military trauma patients. The Department of Defense has mandated that all service members receive role-based TCCC training and certification. Simulation education can increase procedural skills by providing opportunities for deliberate practice in safe, controlled environments. We developed and evaluated the effectiveness of a simulation-based TCCC training intervention to improve participants' skill performance and self-confidence in tourniquet placement. METHODS: This study was a single-blinded, randomized trial with waitlist controls. Army Reserve Officers Training Corp cadets from a single training battalion comprised the study population. After randomization and baseline assessment of all participants, group A alone received focused, simulation-based TCCC tourniquet application training. Three months later, all participants underwent repeat testing, and after crossover, the waitlist group B received the same intervention. Two months later, all cadets underwent a third/final assessment. The primary outcome was tourniquet placement proficiency assessed by total score achieved on a standardized eight-item skill checklist. A secondary outcome was self-confidence in tourniquet application skill as judged by participants' Likert scale ratings. RESULTS: Forty-three Army Reserve Officers Training Corp cadets completed the study protocol. Participants in both group A (n = 25) and group B (n = 18) demonstrated significantly higher performance from baseline to final assessment at 5 months and 2 months, respectively, following the intervention. Mean total checklist score of the entire study cohort increased significantly from 5.53 (SD = 2.00) at baseline to 7.56 (SD = 1.08) at time 3, a gain of 36.7% ( p < 0.001). Both groups rated their self-confidence in tourniquet placement significantly higher following the training. CONCLUSION: A simulation-based TCCC curriculum resulted in significant, consistent, and sustained improvement in participants' skill proficiency and self-confidence in tourniquet placement. Participants maintained these gains 2 months to 5 months after initial training. LEVEL OF EVIDENCE: Therapeutic/care management; Level II.

Collaboration between civilian and military healthcare professionals: a better way for planning, preparing, and responding to all hazard domestic events.

Collaboration is used by the US National Security Council as a means to integrate inter-federal government agencies during planning and execution of common goals towards unified, national security. The concept of collaboration has benefits in the healthcare system by building trust, sharing resources, and reducing costs. The current terrorist threats have made collaborative medical training between military and civilian agencies crucial. This review summarizes the long and rich history of collaboration between civilians and the military in various countries and provides support for the continuation and improvement of collaborative efforts. Through collaboration, advances in the treatment of injuries have been realized, deaths have been reduced, and significant strides in the betterment of the Emergency Medical System have been achieved. This review promotes collaborative medical training between military and civilian medical professionals and provides recommendations for the future based on medical collaboration.

Transient narrowing of a wide QRS tachycardia. What is the mechanism?

Electrocardiogram showing a regular wide QRS tachycardia with left branch block (LBBB) like in morphology at 200 beats per minute (bpm). During electrophysiology study, it suddenly gets narrow and faster. What is the mechanism of the switch from a broad complex to a narrow complex tachycardia?

Spanish Results of the Second European Cardiac Resynchronization Therapy Survey (CRT-Survey II).

INTRODUCTION AND OBJECTIVES: We describe the results for Spain of the Second European Cardiac Resynchronization Therapy Survey (CRT-Survey II) and compare them with those of the other participating countries. METHODS: We included patients undergoing CRT device implantation between October 2015 and December 2016 in 36 participating Spanish centers. We registered the patients' baseline characteristics, implant procedure data, and short-term follow-up information until hospital discharge. RESULTS: Implant success was achieved in 95.9%. The median [interquartile range] annual implantation rate by center was significantly lower in Spain than in the other participating countries: 30 implants/y [21-50] vs 55 implants/y [33-100]; P=.00003. In Spanish centers, there was a lower proportion of patients ≥ 75 years (27.9% vs 32.4%; P=.0071), a higher proportion in New York Heart Association functional class II (46.9% vs 36.9%; P <.00001), and a higher percentage with electrocardiographic criteria of left bundle branch block (82.9% vs 74.6%; P <.00001). The mean length of hospital stay was significantly lower in Spanish centers (5.8±8.5 days vs 6.4±11.6; P <.00001). Spanish patients were more likely to receive a quadripolar LV lead (74% vs 56%; P <.00001) and to be followed up by remote monitoring (55.8% vs 27.7%; P <.00001). CONCLUSIONS: The CRT-Survey II shows that, compared with other participating countries, fewer patients in Spain aged ≥ 75 years received a CRT device, while more patients were in New York Heart Association functional class II and had left bundle branch block. In addition, the length of hospital stay was shorter, and there was greater use of quadripolar LV leads and remote CRT monitoring.

Implantation of single-lead atrioventricular permanent pacemakers guided by electroanatomic navigation without the use of fluoroscopy.

AIMS: Fluoroscopy is the standard and almost unique tool used for cardiac imaging during permanent pacemaker implantation, and its use implies exposure of patients and operators to radiation. The usefulness for this purpose of electroanatomic systems not based on fluoroscopy is unknown. Our aim was to study the feasibility of implanting single-lead VDD pacemakers without the use of fluoroscopy. METHODS AND RESULTS: EnSite NavX, a catheter navigation tool based on the creation of a voltage gradient across the thorax of the patient, was used as an exclusive imaging tool during the implantation of single-lead atrioventricular (VDD) permanent pacemakers in 15 consecutive patients with atrioventricular block and normal sinus node function. A retrospective series of 15 consecutive patients in whom VDD pacemakers were implanted under fluoroscopic guidance was used as a control group. The pacemaker could be implanted in all patients. Time spent to obtain the right ventricle anatomy was 10.1 +/- 5.4 min and time to place the lead in an adequate position was 10.1 +/- 7.8 min. Total implant time was 59.3 +/- 15.6 min (51.5 +/- 12.3 min in the control group; P = 0.14). In one patient, a short pulse of radioscopy was needed for a correct catheterization of the subclavian vein. No complications were observed during the procedure. One lead dislodgement that required re-operation was detected 24 h after implantation. At 3 months follow-up, all pacemakers were functioning properly, with adequate pacing and sensing thresholds. CONCLUSION: Electroanatomic navigation systems such as NavX can be used for cardiac imaging during single-lead atrioventricular pacemaker implantation as a reliable and safe alternative to fluoroscopy.

[Therapeutic success of a prospective cardioversion protocol for persistent atrial fibrillation]. / Rendimiento terapéutico de un protocolo prospectivo de cardioversión en la fibrilación auricular persistente.

INTRODUCTION AND OBJECTIVES: The best therapeutic approach for persistent atrial fibrillation has yet to be defined. Our aim was to investigate the effects of cardioversion in unselected patients with persistent atrial fibrillation who were treated according to a strict protocol involving pretreatment, cardioversion, and follow-up. METHODS: Consecutive patients with persistent atrial fibrillation of at least 1 months' duration were included prospectively in a cardioversion protocol that involved standard antiarrhythmic pretreatment, with amiodarone being offered first, and follow-up. RESULTS: The study included 295 patients, 87.5% of whom were taking the antiarrhythmic drug amiodarone. Sinus rhythm was restored in 92.5%, with pharmacologic cardioversion occurring in 9.5%. The recurrence rate was 33.5% in the first month and 54.9% by month 12. Antiarrhythmic treatment had to be modified in 10.8% of patients. Independent risk factors for recurrence during the first year after cardioversion were an atrial fibrillation duration greater than one year, previous cardioversion, and left ventricular dilatation. A simple risk scoring system was able to differentiate between subgroups of patients with a low, intermediate or high risk of recurrence in the first year after cardioversion. CONCLUSIONS: Sinus rhythm was maintained for 1 year after effective cardioversion in 45.1% of patients who received homogeneous antiarrhythmic pretreatment. There were few side effects. Recurrence can be predicted using clinical variables such as left ventricular dilatation, arrhythmia duration, and previous cardioversion.

Just-in-time learning is effective in helping first responders manage weapons of mass destruction events.

BACKGROUND: Chemical, biologic, radiologic, nuclear, and explosive (CBRNE) incidents require specialized training. The low frequency of these events leads to significant skill decay among first responders. To address skill decay and lack of experience with these high-impact events, educational modules were developed for mobile devices to provide just-in-time training to first responders en route to a CBRNE event. This study assessed the efficacy and usability of the mobile training. METHODS: Ninety first responders were randomized to a control or an intervention group. All participants completed a pretest to measure knowledge of CBRNE topics. The intervention group then viewed personal protective equipment and weapons of mass destruction field management videos as an overview. Both groups were briefed on a disaster scenario (chemical nerve agent, radiologic, or explosives) requiring them to triage, assess, and manage a patient. Intervention group participants watched a mobile training video corresponding to the scenario. The control group did not receive prescenario video training. Observers rated participant performance in each scenario. After completing the scenarios, all participants answered a cognitive posttest. Those in the intervention group also answered a questionnaire on their impressions of the training. RESULTS: The intervention group outperformed the control group in the explosives and chemical nerve agent scenarios; the differences were statistically significant (explosives, mean of 26.32 for intervention and 22.85 for control, p < 0.01; nerve agent, mean of 23.14 for intervention and 16.61 for control, p < 0.01). There was no statistically significant difference between the groups in the radiologic scenario (mean, 12.7 for intervention and 11.8 for control; p = 0.51). The change in pretest to posttest cognitive scores was significantly higher in the intervention group than in the control group (t = 3.28, p < 0.05). CONCLUSION: Mobile just-in-time training improved first-responder knowledge of CBRNE events and is an effective tool in helping first responders manage simulated explosive and chemical agent scenarios. LEVEL OF EVIDENCE: Therapeutic/care management study, level II.

[Relationship of C-reactive protein levels with angiographic findings and markers of necrosis in non-ST-segment elevation acute coronary syndrome]. / Relación de los valores de proteína C reactiva con los hallazgos angiográficos y los marcadores de necrosis en el síndrome coronario agudo sin elevación del segmento ST.

INTRODUCTION AND OBJECTIVES: The mechanism responsible for elevated C-reactive protein levels (inflammation of the ruptured atherosclerotic plaque or myocardial necrosis) in acute coronary syndromes is controversial. The aim of this study was to investigate the relationship between C-reactive protein levels and angiographic complexity of the culprit lesion and troponin elevation in patients with non-ST elevation acute coronary syndromes. PATIENTS AND METHOD: The study group consisted of 125 patients with single-vessel disease. Troponin-I and C-reactive protein were measured, and the complexity of the culprit lesion was analyzed (TIMI flow and thrombus). Information on age, sex, smoking habit, hypertension, hypercholesterolemia and diabetes was obtained from the medical record. RESULTS: The quartile distribution of C-reactive protein showed more patients with TIMI flow < 3 (31%, 28%, 18%, and 55%; P=.02), thrombus (3%, 6%, 7%, and 28%; P=.007) and troponin-I elevation (19%, 44%, 50%, and 66%; P=.003) in the fourth quartile. Multivariate analysis showed both thrombus (OR = 4.1; 95% CI, 1.2-14.3; P=.03) and troponin elevation (OR = 2.6; 95% CI, 1.1-6.3; P=.03) to be associated with C-reactive protein > 18 mg/L (fourth quartile cut-off). When treated as a continuous variable, higher levels of C-reactive protein were also associated with thrombus (P=.02) and troponin elevation (P=.003). No other clinical variables were related with C-reactive protein levels. CONCLUSIONS: Both angiographic complexity of the culprit lesion and elevated troponin level are related with increased C-reactive protein levels in non-ST elevation acute coronary syndromes.

Medium-term results of cryoballoon ablation of the pulmonary veins in patients with paroxysmal and persistent atrial fibrillation. First experience of a Spanish center.

PURPOSE: Cryoballoon ablation of the pulmonary veins (CAPV) is a new technique that could have similar results to radiofrequency procedures, but with fewer complications. We analyzed the outcomes and safety of this technique in a consecutive cohort of patients with atrial fibrillation (AF). METHODS: A total of 63 patients with paroxysmal (n = 40) or persistent (n = 23) AF were studied. Patient follow-up was performed at 3 months and then every 6 months with 72-h continuous electrocardiographic recordings. RESULTS: A total of 262 pulmonary veins were treated; 60.3 % of the cases presented normal pulmonary vein drainage with 4 pulmonary veins, and 23.8 % of the cases presented a common left-sided antrum. Complete isolation of all veins was achieved in 95.2 % of cases with 10.3 ± 2.8 (mean ± standard deviation) applications per patient. Transient right phrenic nerve injury was the most common complication (4.7 %). Median follow-up was 5.5 months. The probability of being free of recurrence at 1 and 2 years was, respectively, 86.2 and 72.2 % for paroxysmal AF and 49 and 36.4 % for persistent AF (P = 0.012). Patients with structural heart disease experienced recurrence more often than patients with a normal heart (62.5 versus 24.5 %; P = 0.03). CONCLUSIONS: CAPV appears to be a safe and effective procedure for the treatment of patients with AF, particularly those with paroxysmal AF and no structural heart disease.

Syncope and bundle branch block. Diagnostic yield of a stepped use of electrophysiology study and implantable loop recorders.

INTRODUCTION AND OBJECTIVES: The objective of this study was to determine the diagnostic yield of a stepped protocol involving an electrophysiologic study (EPS) and implantable loop recorders (ILR) in patients with syncope and bundle branch block (BBB). METHODS: Eighty-five consecutive patients referred for syncope and BBB after initial non-diagnostic assessment underwent EPS including a pharmacological challenge with procainamide. Those patients without indication for defibrillator implantation received ILRs. Follow-up continued until diagnosis or end of battery life. RESULTS: The EPS was diagnostic in 36 patients (42%). The most frequent diagnoses were paroxysmal atrioventricular block (AVB) (n=27), followed by ventricular tachycardia (VT) (n=6). All patients with VT had structural heart disease; left BBB was more prevalent in this group. Thirty-eight patients received ILRs and diagnosis was achieved in 13 (34%) of them; paroxysmal AVB (n=10) was the most frequent diagnosis. Median follow-up to diagnosis of paroxysmal AVB was 97 days (interquartile range 60-117 days). Paroxysmal AVB was more frequent in patients with right BBB and prolonged PR interval and/or axis deviation. We found no occurrence of VT or arrhythmic death during follow-up. CONCLUSIONS: The most common etiology of syncope in patients with BBB was paroxysmal AVB, followed by VT. The stepped use of EPS and ILR in negative patients enables us to safely achieve a high diagnostic yield, given that VT is usually diagnosed during EPS.