Refractory Ventricular Fibrillation Research Articles

CARDIOGENIC SHOCK DUE TO SPONTANEOUS CORONARY ARTERY DISSECTION

Abstract Spontaneous coronary artery dissection (SCAD) is an important but rare cause of myocardial infarction (MI) in young adults, particularly women. Current guidelines recommend conservative treatment, given the low angiographic success and the high complication rate of percutaneous coronary intervention. However, in SCAD patients presenting with STEMI or cardiogenic shock the needs of urgent revascularization is critical and PCI may be life threatening. We present a case report occurs in our Hospital of a 42–year–old young woman without cardiovascular risk factors or notable comorbidities which was admitted to our emergency department for typical chest pain. At admission the patient had a cardiovascular arrest from refractory ventricular fibrillation who was rescued according to ACLS protocol. After resumption of ROSC, EKG showed anterolateral STEMI (FIGURE 1). Bedside echocardiography showed a severe reduction in systolic function (EF 30%) due to akinesia of the apex, septum and antero–lateral wall, with absence of noticeable valvulopathy, pericardial effusion or pathological findings in the right heart sections. Therefore the patient underwent to Cath–lab for emergent coronary angiography that showed ostial DA subocclusion with SCAD type 2a on middle tract (Figure 2) IVUS (intravascular ultrasound) imaging confirmed the diagnosis of SCAD, served to guided angioplasty on the LM–DA axis and to confirme optimal stent placement (FIGURE 3). Subsequently, the course was complicated by a double shock component: first SCAI C cardiogenic shock that requested or IMPELLA CP implantation and second haemorrhagic shock due to profound hepatic bleeding because of traumatic injury caused by prolonged resuscitation maneuvers. Mechanical ventricular support ensured haemodynamic stability to allow percutaneous embolisation of the hepatic arteries and patient stabilization. Once the haemorrhagic focus was treated and cardiac function recovered, the patient‘s condition gradually improved leading to a rapid weaning of haemodynamic and respiratory support. No neurological sequelae were observed after the acute phase. Conclusions 1) Urgent revascularization in patients with SCAD and high clinical instability is life threatening. IVUS imaging is crucial to confirm the diagnosis and guide the procedure. 2) The IMPELLA support in this case provided short–term haemodynamic support in a double component of shock.

PERCUTANEOUS LEFT STELLATE GANGLION BLOCK TO INCREASE VENTRICULAR FIBRILLATION THRESHOLD AND DEFIBRILLATION SUCCESS RATE IN ACUTE FULMINANT MYOCARDITIS WITH ELECTRICAL STORM

Abstract Introduction Acute fulminant myocarditis represents a predisposing substrate for life–threatening ventricular arrhythmias (VAs). Percutaneous left stellate ganglion block (PLSGB) usage has been reported for the prevention of recurrent VAs, but clinical data on its acute effect on ongoing ventricular fibrillation (VF) are missing. Case A 57–years–old man suffering gastroenteritis and fever in the past week presented in the ED with typical chest pain. ECG depicted infero–lateral ST–segment elevation, cardiac ultrasound showed a mildly reduced LVEF and coronary angiography ruled out coronary lesions. In the following hours the patient developed frequent premature ventricular complexes with R on T phenomenon triggering short coupled torsade de pointes with rapid degeneration into VF. VAs episodes, initially responsive to single DC shock, kept recurring despite intravenous (iv) amiodarone, iv lidocaine and iv correction of potassium and magnesium. The patient was therefore treated with deep sedation, intubation and ECMO VA placement; still, he reached a status of persistently ongoing VF, refractory even to DC shocks (n=20). Therefore, ultrasound–guided PLSGB using a local bolus of lidocaine 150 mg + ropivacaine 50 mg was performed. After 5 minutes, a single DC shock was delivered, effective in achieving a stable sinus rhythm at 35 bpm with no more recurrences. Despite electrical stabilization, the patient developed a severe cardiogenic shock due to bradycardia and severe biventricular disfunction, treated with vasopressin and dobutamine. In the next 48 hours we observed a significant improvement, resumption of biventricular contractility and absence of VAs recurrences, so the patient was slowly weaned off ECMO and vasopressors. Immunological tests showed Enterovirus IgM positivity, while endomyocardial biopsy was negative for inflammatory infiltrates in the analyzed sections. Cardiac MRI (performed 10 days after onset) showed edema and non–ischemic LGE in the antero–lateral and infero–lateral basal subepicardial regions of the left ventricle, LVEF was 55%. After 15 days from admission, despite ongoing amiodarone and bisoprolol, the patient developed a run of monomorphic VA of 30 beats at 170 bpm, therefore he underwent sICD implantation. Conclusion PLSGB played a key role for the acute management of refractory VF unresponsive to DC shocks, allowing for acute stabilization. More clinical data are needed on acute neuromodulation for electrical storm.

Electrical Storm/Refractory Ventricular Tachycardia.

This simulation case was created for emergency medicine (EM) residents at all levels of training. Cardiac electrical storm (ES) is commonly defined as three or more episodes of sustained ventricular tachycardia, ventricular fibrillation, or three shocks from an implantable defibrillator within a 24 hour period.1 This can occur in up to 30-40% of patients with implantable defibrillators; however, it may also present in a wide variety of patients, including those with structural heart disease, myocardial infarction, electrolyte disturbances, and channelopathies.2,3 With each subsequent episode of ventricular arrhythmia, the arrhythmogenic potential of the heart may increase secondary to increased intracellular calcium dysregulation, myocardial injury, and increased endogenous release of catecholamines. The increased pain and catecholamine release from cardioversion/defibrillation and exogenous epinephrine during cardiac arrest further exacerbates ES.2 This carries a significant mortality risk of up to 12% in the first 48 hours.3This case involves a basic knowledge of the Advanced Cardiac Life Support (ACLS) for ventricular tachycardia, both with and without a pulse, and the application of Sgarbossa criteria in a patient with an ST elevation myocardial infarction (STEMI) which makes it ideal for the PGY-1. However, the case quickly becomes refractory to the basic management prescribed in ACLS, requiring trouble shooting and quick thinking about deeper pathophysiology, a skill that is crucial for all emergency medicine physicians. There are multiple ways to troubleshoot this case, making for a good variety of discussion and recent literature review on the complexities of a relatively common arrhythmia, ventricular tachycardia. By the end of this simulation, learners should be able to: 1) recognize unstable ventricular tachycardia and initiate ACLS protocol, 2) practice dynamic decision making by switching between various ACLS algorithms, 3) create a thoughtful approach for further management of refractory ventricular tachycardia, 4) interpret electrocardiogram (ECG) with ST-segment elevation (STE) and left bundle branch block (LBBB), 5) appropriately disposition the patient and provide care after return of spontaneous circulation (ROSC), 6) navigate a difficult conversation with the patient's husband when she reveals that the patient's wishes were to not be resuscitated. This simulation was performed using high-fidelity simulation followed by an immediate debriefing with nine learners who directly participated in the SIM and twenty-three residents, who were online observers via Zoom. This case was done during our conference day, and there were a total of approximately forty total learners comprised of medical students, PGY-1, PGY-2 and PGY-3 residents. There were several medical students who also observed via Zoom but were not surveyed, and the survey was sent to 32 learners. The case was run three separate times with each session consisting of three-four learners at the same level of training, with other learners in the same level of training observing via Zoom™ video platform. Since we can only have a team of three-four learners participate per group during simulation, the rest of the learners were observing the case and the debrief. There was one simulation instructor and one technician. We sent an online survey to all the participants and the observers after the debrief via surveymonkey.com. The survey collected responses to the following statements: (1) the case was believable, (2) the case had right amount of complexity, (3) the case helped in improving medical knowledge and patient care, (4) the simulation environment gave me a real-life experience and, (5) the debriefing session after simulation helped improve my knowledge. Likert scale was used to collect the responses. A total of thirteen participants responded to the survey. One hundred percent of them either strongly agreed or agreed that the case was believable and that it helped in improving medical knowledge and patient care. Fifty-four percent strongly agreed, 38 percent agreed, and eight percent were neutral about the case having the right amount of complexity. Thirty one percent strongly agreed, 61 percent agreed, and eight percent were neutral about the case giving them real-life experience. All of them agreed that the debriefing session helped them improve their knowledge. The high-fidelity simulation case was helpful with educating learners with ventricular tachycardia and fibrillation. Learners learned how to switch between various ACLS algorithms and how to manage a patient with refractory ventricular fibrillation. Learners enforced their knowledge in how to communicate with patient's family members when the patient does not want resuscitation. Stable ventricular tachycardia, unstable ventricular tachycardia, refractory ventricular tachycardia, electrical storm, STEMI equivalents, medical simulation.

Resuscitation Update - What's New?

Perfect, uninterrupted basic life support (BLS) is the key for successful cardiopulmonary resuscitation (CPR) in out-of-hospital cardiac arrest (OHCA). Time plays an important role in the treatment of OHCA. This applies both to the time until the start of BLS and the reduction of all pauses during resuscitation, especially chest compressions. In 2022, the rate of bystander-CPR showed an absolute increase of 4% compared to previous years. The bystander-CPR rate is currently above 50%. Compared to OHCA in adults, cardiac arrest in children is rare in Germany. In the period from 2007 to 2021, the incidence was 3.08 per 100000 children. In addition, the etiology in children varies depending on the age group. While hypoxia is often the cause of circulatory arrest in younger children, trauma and drowning accidents are the main causes in school-age children. Different additional diagnostic and therapeutic strategies have been evaluated over the last years. Point-of-care ultrasound during resuscitation should only be performed by experienced users. Interrupting chest compressions and thus prolonging the no-flow phases must be avoided. Double sequential external defibrillation after the third shock can successfully terminate refractory ventricular fibrillation. While further studies are needed, emergency medical systems should train their teams to avoid complications. In refractory OHCA, extracorporeal CPR should be considered. In the case of in-hospital cannulation, immediate transport should be weighed against impaired chest compression quality. Therefore, transportation under CPR is only beneficial if there is an indication for further treatment.

Scrutinizing the Role of Venoarterial Extracorporeal Membrane Oxygenation: Has Clinical Practice Outpaced the Evidence?

The use of venoarterial extracorporeal membrane oxygenation (VA-ECMO) for temporary mechanical circulatory support in various clinical scenarios has been increasing consistently, despite the lack of sufficient evidence regarding its benefit and safety from adequately powered randomized controlled trials. Although the ARREST trial (Advanced Reperfusion Strategies for Patients with Out-of-Hospital Cardiac Arrest and Refractory Ventricular Fibrillation) and a secondary analysis of the PRAGUE OHCA trial (Prague Out-of-Hospital Cardiac Arrest) provided some evidence in favor of VA-ECMO in the setting of out-of-hospital cardiac arrest, the INCEPTION trial (Early Initiation of Extracorporeal Life Support in Refractory Out-of-Hospital Cardiac Arrest) has not found a relevant improvement of short-term mortality with extracorporeal cardiopulmonary resuscitation. In addition, the results of the recently published ECLS-SHOCK trial (Extracorporeal Life Support in Cardiogenic Shock) and ECMO-CS trial (Extracorporeal Membrane Oxygenation in the Therapy of Cardiogenic Shock) discourage the routine use of VA-ECMO in patients with infarct-related cardiogenic shock. Ongoing clinical trials (ANCHOR [Assessment of ECMO in Acute Myocardial Infarction Cardiogenic Shock, NCT04184635], REVERSE [Impella CP With VA ECMO for Cardiogenic Shock, NCT03431467], UNLOAD ECMO [Left Ventricular Unloading to Improve Outcome in Cardiogenic Shock Patients on VA-ECMO, NCT05577195], PIONEER [Hemodynamic Support With ECMO and IABP in Elective Complex High-risk PCI, NCT04045873]) may clarify the usefulness of VA-ECMO in specific patient subpopulations and the efficacy of combined mechanical circulatory support strategies. Pending further data to refine patient selection and management recommendations for VA-ECMO, it remains uncertain whether the present usage of this device improves outcomes.

The impact of alternate defibrillation strategies on shock-refractory and recurrent ventricular fibrillation: A secondary analysis of the DOSE VF cluster randomized controlled trial

BackgroundThe DOSE VF randomized controlled trial (RCT) employed a pragmatic definition of refractory ventricular fibrillation (VF after three successive shocks). However, it remains unclear whether the underlying rhythm during the first three shocks was shock-refractory or recurrent VF. ObjectiveTo explore the relationship between alternate defibrillation strategies employed during the DOSE VF RCT and the type of VF, either shock-refractory VF or recurrent VF, on patient outcomes. MethodsWe performed a secondary analysis of the DOSE VF RCT. We categorized cases as shock-refractory or recurrent VF based on pre-randomization shocks (shocks 1–3). We then analyzed all subsequent (post-randomization) shocks to assess the impact of standard, vector change (VC) or double sequential external defibrillation (DSED) shocks on clinical outcomes employing logistic regression adjusted for Utstein variables, antiarrhythmics, and epinephrine. ResultsWe included 345 patients; 60 (17%) shock-refractory VF, and 285 (83%) recurrent VF. Patients in recurrent VF had greater survival than shock-refractory VF (OR: 2.76 95% CI [1.04, 7.27]). DSED was superior to standard defibrillation for survival overall, and for patients with shock-refractory VF (28.6% vs 0%, p = 0.041) but not for those in recurrent VF. DSED was superior to standard defibrillation for return of spontaneous circulation (ROSC) and neurologic survival for shock-refractory and recurrent VF. VC defibrillation was not superior for survival or ROSC overall, for shock-refractory, or recurrent VF groups, but was superior for VF termination across all groups. ConclusionDSED appears to be the superior defibrillation strategy in the DOSE VF trial, irrespective of whether the preceding VF is shock-refractory or recurrent.

Association of coronary angiography with ST-elevation and no ST-elevation in patients with refractory ventricular fibrillation – A substudy of the DOuble SEquential External Defibrillation for Refractory Ventricular Fibrillation (DOSE-VF randomized control trial)

BackgroundRefractory ventricular fibrillation or pulseless ventricular tachycardia (rVF/pVT) during out-of-hospital cardiac arrest (OHCA) is associated with poor survival. Double sequential defibrillation (DSED) and vector change (VC) improved survival for rVF/pVT in the DOSE-VF RCT. However, the role of angiography and percutaneous coronary intervention (angiography/PCI) during the trial is unknown. ObjectivesTo determine the incidence of ST-elevation (STE) and no ST-elevation (NO-STE) on post-arrest ECG and the use of angiography/PCI in patients with rVF/pVT during the DOSE-VF RCT. MethodAdults (≥18-years) with rVF/pVT OHCA randomized in the DOSE-VF RCT who survived to hospital admission were included. The primary analysis compared the proportion of angiography in STE and NO-STE. We performed regression modelling to examine association between STE, the interaction with defibrillation strategy, and survival to discharge controlling for known covariates. ResultsWe included 151 patients, 74 (49%) with STE and 77 (51%) with NO-STE. The proportion of angiography was higher in the STE cohort than NO-STE (87.8% vs 44.2%, p < 0.001); similarly the proportion of PCI was also higher (75.7% vs 9.1%, p < 0.001). Survival to discharge was similar between STE and NO-STE (63.5% vs 51.9%, p = 0.15). Use of angiography/PCI did not differ between defibrillation strategies. Decreased age (OR 0.95, 95% CI 0.92–0.98; p = 0.001) and angiography (OR 9.33, 95% CI 3.60–26.94; p < 0.001) were predictors of survival; however, STE was not. ConclusionWe found high rates of angiography/PCI in patients with STE compared to NO-STE, however similar rates of survival. Angiography was an independent predictor of survival. Improved rates of survival employing DSED and VC were independent of angiography/PCI.

Coronary Artery Bypass Grafting for Refractory Ventricular fibrillation after the Release of the Aortic Cross-Clamp in Patients Undergoing Aortic Valve Replacement: A Case Report

Background: Ventricular fibrillation (VF) is a known complication after the release of the aortic cross-clamp (ACC) during cardiopulmonary bypass (CPB) surgery. Various factors contribute to persistent refractory VF, making its management challenging. This case report describes the successful treatment of postoperative refractory VF by coronary artery bypass grafting (CABG) in a patient undergoing aortic valve replacement (AVR) with ACC release. Case Presentation: A 52-year-old woman with a history of hypertension and ischemic cerebral infarction presented with symptoms of chest tightness, dyspnoea and palpitations. She underwent a modified maze procedure of radiofrequency ablation, mitral repair, left atrial appendage closure and mechanical AVR under a CPB procedure. Following the ACC release, the patient experienced recurrent VF that was unresponsive to standard interventions such as lidocaine, amiodarone and direct current shocks. The suspicion of right coronary artery (RCA) insufficiency led to the decision to perform CABG using the great saphenous vein. After the CABG procedure, the patient's heart rhythm gradually returned to sinus rhythm, and she had an uneventful recovery. Discussion and Conclusions: Refractory VF after the ACC release can pose diagnostic and treatment challenges. In this case, RCA insufficiency was suspected as the cause of refractory VF. The absence of blood flow in the proximal RCA and the presence of distal blood return during cardiac surface exploration supported this suspicion. Coronary artery bypass grafting using the great saphenous vein successfully restored normal sinus rhythm, confirming the diagnosis. This case emphasises the importance of considering coronary artery stenosis or occlusion as a potential cause of refractory VF after the ACC release during CPB, with CABG serving as a viable alternative treatment.

The Impact of Double Sequential Shock Timing on Outcomes During Refractory Out –of-Hospital Cardiac Arrest

BackgroundAnimal studies suggest the efficacy of double sequential external defibrillation (DSED) may depend on the interval between the two shocks, or “DSED interval”. No human studies have examined this concept. ObjectivesTo determine the relationship between DSED interval and termination of ventricular fibrillation (VFT), return of spontaneous circulation (ROSC), survival to hospital discharge, and favourable neurological status (MRS < 2) for patients in refractory VF. MethodsWe performed a retrospective review of adult (≥18 years) out-of-hospital cardiac arrest between January 2015 and May 2022 with refractory VF who received ≥1 DSED shock. DSED interval was divided into four pre-defined categories. We examined the association between DSED interval and patient outcomes using general estimated equation logistic regression or Fisher's exact test. ResultsAmong 106 included patients, 303 DSED shocks were delivered (median 2, IQR 1-3). DSED intervals of 75-125 msec (OR 0.39, 95% CI 0.16-0.98), 125-500 msec (OR 0.36, 95% CI 0.16-0.82), and >500 msec (OR 0.27, 95% CI 0.11-0.63) were associated with lower probability of VF termination compared to <75 msec interval. DSED interval of >75 msec was associated with lower probability of ROSC compared to <75 msec interval (OR 0.37, 95% CI 0.14-0.98). No association was noted between DSED interval and survival to hospital discharge or neurologic outcome. ConclusionsAmong patients in refractory VF a DSED interval of less than 75 msec was associated with improved rates of VF termination and ROSC. No association was noted between DSED interval and survival to hospital discharge or neurologic outcome.

Abstract 419: Incidence of True Refractory Ventricular Fibrillation in Patients Meeting a Pragmatic Definition of Refractory Ventricular Fibrillation

Introduction: Refractory VF, pragmatically defined as a shockable presenting rhythm that is still observed after three shocks and associated 2-minute CPR cycles, is often encountered in out-of-hospital cardiac arrest (OHCA) and is associated with worse outcomes. A recent clinical trial tested alternative strategies for treating patients meeting this definition of refractory VF. It is unknown how often standard defibrillation truly fails to terminate VF in these patients. Methods: Using the prospective AmsteRdam REsuscitation STudies (ARREST) registry of OHCA patients, we examined termination of VF in patients meeting the pragmatic definition of refractory VF between 2016 and 2019. All patients received standard defibrillation. We reviewed ECG waveforms from all AEDs and manual defibrillators to analyze termination of VF to a non-shockable rhythm at five seconds after each of the first 3 shocks. Refibrillation was defined as recurrence of VF after a shock terminated VF. Results: Out of 1573 OHCAs with an initial shockable rhythm, we analyzed the 453 cases (29%) that met the pragmatic definition of refractory VF. Median time to first shock was 8.0 (IQR 6.3-9.7) minutes; in 65% an AED was used. The first three shocks terminated VF at least once in 96% of the patients, at least twice in 81%, and all three times in 57%. Altogether, VF was terminated by 78% of all individual shocks. In 4% of patients all three shocks failed to terminate VF (Figure). Median time to refibrillation was 32 (IQR 12-61) seconds. ROSC at any time occurred in 59% of patients; 27% survived to discharge. Conclusions: In patients meeting a pragmatic definition of refractory VF, true refractory VF without termination of the shockable rhythm by any of the first three shocks was rare. Instead, VF was successfully terminated by most shocks and recurred during the ensuing CPR cycle. Therefore, the mechanism of benefit from alternative defibrillation strategies in these patients is unclear.

Abstract 316: Reperfusion With Mild versus Moderate Hypothermia in a Swine Model of Extracorporeal Cardiopulmonary Resuscitation

Background: Targeted temperature management (TTM) at lower temperatures has shown variable neuroprotective benefits in clinical trials of cardiac arrest. We hypothesized that moderate hypothermia at the time of VA-ECMO reperfusion followed by early rewarming would reduce brain injury in a swine model of refractory VF, compared to mild hypothermia. Methods: Fourteen female pigs had electrically induced VF and conventional CPR for 30 minutes. Animals were cannulated to VA-ECMO and randomized to TTM to 34°C for 4 hours (mild hypothermia, n=7) or 24°C for 1 hour followed by early rewarming to 34°C over 3 hours (moderate hypothermia, n=7). Cooling was initiated upon ECMO reperfusion by circulating ice water through the oxygenator. Brain temperature and cerebral and systemic hemodynamics were continuously monitored. After four hours of post-arrest and ECMO care, brain tissue was obtained for examination. Groups were compared using paired t- and Wilcoxon rank sum tests. Results: The mean time to target brain temperature was 5 and 35 minutes in the mild and moderate groups, respectively (Panel, A). CPR hemodynamics were similar. Carotid blood flow (CBF) was higher in moderate hypothermia animals (79.0±1.56 vs 60.7±1.86% pre-arrest baseline, P &lt;0.001) throughout the post-arrest period. There were no differences in ECMO flow, mean arterial pressure, vasopressor/fluid requirement, bleeding, or thromboelastography. No significant difference in histologic damage score was observed between groups (10.5 [7, 11.8] vs 13 [9, 20], with 24°C vs 34°C respectively P =0.25; Panel, B). Immunohistochemistry markers for white matter and neuronal injury also did not significantly diverge. Conclusion: In a swine model of refractory cardiac arrest treated with ECPR, moderate hypothermia initiated upon reperfusion followed by early rewarming did not appear to be neuroprotective. Histological brain injury at 4 hours post-resuscitation was not affected by the degree of hypothermia.

Out-of-hospital cardiac arrest treated with prehospital double sequential external defibrillation during eCPR in refractory VF — a case report

BackgroundDouble sequential external defibrillation (DSED) has demonstrated increased survival with good neurological outcome in a recent randomized controlled trial. DSED has not been studied in patients with extracorporeal cardiopulmonary resuscitation (eCPR).CaseWe present the first case of prehospital eCPR with ongoing refractory ventricular fibrillation (VF), terminated by DSED. After six shocks, return of spontaneous circulation was initially achieved; however, the patient went into recurrent VF. ECPR was performed prehospital, with VF still refractory after three more shocks. DSED successfully terminated VF and showed a further increase in etCO2 and near-infrared spectroscopy cerebral oximetry values.ConclusionDSED can be a sufficient strategy for patients in refractory VF while on eCPR and should be evaluated in further studies.

Long-term prognostic significance of gasping in out-of-hospital cardiac arrest patients undergoing extracorporeal cardiopulmonary resuscitation: a post hoc analysis of a multi-center prospective cohort study

BackgroundGasping during resuscitation has been reported as a favorable factor for out-of-hospital cardiac arrest. We examined whether gasping during resuscitation is independently associated with favorable neurological outcomes in patients with refractory ventricular fibrillation or pulseless ventricular tachycardia (VF/pVT) undergoing extracorporeal cardiopulmonary resuscitation ECPR.MethodsData from a 2014 study on advanced cardiac life support for ventricular fibrillation with extracorporeal circulation in Japan (SAVE-J), which examined the efficacy of ECPR for refractory VF/pVT, were analyzed. The primary endpoint was survival with a 6-month favorable neurological outcome in patients who underwent ECPR with or without gasping during resuscitation. Multivariate logistic regression analysis was performed to evaluate the association between gasping and outcomes.ResultsOf the 454 patients included in the SAVE-J study, data from 212 patients were analyzed in this study after excluding those with missing information and those who did not undergo ECPR. Gasping has been observed in 47 patients during resuscitation; 11 (23.4%) had a favorable neurological outcome at 6 months. Multivariate logistic regression analysis showed that gasping during resuscitation was independently associated with a favorable neurological outcome (odds ratio [OR], 10.58 [95% confidence interval (CI) 3.22–34.74]). The adjusted OR for gasping during emergency medical service transport and on arrival at the hospital was 27.44 (95% CI 5.65–133.41).ConclusionsGasping during resuscitation is a favorable factor in patients with refractory VF/pVT. Patients with refractory VF/pVT with continuously preserved gasping during EMS transportation to the hospital are expected to have more favorable outcomes.

Management of severe tricuspid valve regurgitation due to ruptured papillary muscle in a patient with mediastinitis early after heart transplant.

Even though severe tricuspid regurgitation is not uncommon after cardiac transplantation, primary severe tricuspid regurgitation is rare. We present such a case with additional complexities. The patient was 44-year-old man with a HeartWare durable left ventricular assist device (Heartware Inc) who received a temporary right ventricular assist device (RVAD) with a ProtekDuo cannula (LivaNova Inc USA) for refractory ventricular fibrillation and underwent a heart transplant as United Network for Organ Sharing Status 1, in the presence of partially compensated cardiogenic shock, renal failure. Given complex re-operative surgery in a volume-overloaded patient with unknown pulmonary vascular resistance, an RVAD cannula was preserved and re- inserted during cardiac transplant. Postoperatively he required hemodialysis, had severe primary tricuspid regurgitation discovered after RVAD removal and developed Enterobacter mediastinitis. He underwent complex tricuspid valve repair for flail tricuspid leaflet due to ruptured papillary muscle likely due to RVAD cannula injury, after multiple mediastinal washouts and was followed by delayed chest reconstruction. The patient is doing well, 6 months after discharge to home, asymptomatic, without re-admissions, on renal recovery path, with no tricuspid regurgitation and good biventricular function. Replacing the tricuspid valve in presence of hemodialysis catheter, immunosuppression and mediastinitis could be high risk for endocarditis. Even though we have short-term follow-up, tricuspid valve repair can be an effective way of managing primary severe regurgitation especially when there is a desire or need to avoid valve replacement.

Lethal abdominal compartment syndrome after extracorporeal cardiopulmonary resuscitation in a patient with out-of-hospital cardiac arrest: a case report

BackgroundClinical attempts of extracorporeal cardiopulmonary resuscitation (ECPR) in patients with out-of-hospital cardiac arrest (OHCA) have increased in recent years; however, it also has life-threatening complications. Massive fluid and transfusion resuscitation, shock status, or low cardiac output status during ECPR may lead to ascites and interstitial edema, resulting in secondary abdominal compartment syndrome (ACS).Case presentationA 43-year-old male patient was admitted to the emergency department due to cardiac arrest. Due to refractory ventricular fibrillation, ECPR was initiated. Approximately, 3 h after extracorporeal membrane oxygenation support, abdominal distension and rigidity developed. Therefore, ACS was suspected. Decompression laparotomy was required to relieve elevated intra-abdominal pressure.ConclusionsWe report a case of a patient with OHCA who developed lethal ACS after ECPR. Despite this, the patient was able to recover from several major crises. Regardless of how lethal the patient is, if compartment syndrome develops in any part of the body, we should aggressively consider surgical decompression.

Defibrillation strategies for refractory ventricular fibrillation out-of-hospital cardiac arrest: A systematic review and network meta-analysis.

Double sequential external defibrillation (DSED) and vector-change defibrillation (VCD) have been suggested to enhance clinical outcomes for patients with ventricular fibrillation (VF) refractory of standard defibrillation (SD). Therefore, this network meta-analysis aims to evaluate the comparative efficacy of DSED, VCD, and SD for refractory VF. A systematic review and network meta-analysis synthesizing randomized controlled trials (RCTs) and comparative observational studies retrieved from PubMed, EMBASE, WOS, SCOPUS, and Cochrane through November 15th, 2022. R software netmeta and netrank package (R version 4.2.0) and meta-insight software were used to pool dichotomous outcomes using odds ratio (OR) presented with the corresponding confidence interval (CI). Our protocol was prospectively published in PROSPERO with ID: CRD42022378533. We included seven studies with a total of 1632 participants. DSED was similar to SD in survival to hospital discharge (OR: 1.14 with 95% CI [0.55, 2.83]), favorable neurological outcome (modified Rankin scale ≤2 or cerebral performance category ≤2) (OR: 1.35 with 95% CI [0.46, 3.99]), and return of spontaneous circulation (ROSC) (OR: 0.81 with 95% CI [0.43; 1.5]). In addition, VCD was similar to SD in survival to hospital discharge (OR: 1.12 with 95% CI [0.27, 4.57]), favorable neurological outcome (OR: 1.01 with 95% CI [0.18, 5.75]), and ROSC (OR: 0.88 with 95% CI [0.24; 3.15]). Double sequential external defibrillation and VCD were not associated with enhanced outcomes in patients with refractory VF out-of-hospital cardiac arrest, compared to SD. However, the current evidence is still inconclusive, warranting further large-scale RCTs.

The impact of BMI on arrest characteristics and survival of patients with out-of-hospital cardiac arrest treated with extracorporeal cardiopulmonary resuscitation

AimTo assess the impact of body mass index (BMI) on survival to hospital discharge of patients presenting with refractory ventricular fibrillation treated with extracorporeal cardiopulmonary resuscitation. We hypothesize that due to limitations in pre-hospital care delivery, people with high BMI have worse survival after prolonged resuscitation and ECPR. MethodsThis study is a retrospective single-centre study that included patients suffering refractory VT/VF OHCA from December 2015 to October 2021 and had a BMI calculated at hospital admission. We compared the baseline characteristics and survival between patients with obesity (>30 kg/m2) and those without (≤30 kg/m2). ResultsTwo-hundred eighty-three patients were included in this study, and two-hundred twenty-four required mechanical support with veno-arterial extracorporeal cardiopulmonary membrane oxygenation (VA ECMO). Patients with BMI > 30 (n = 133) had significantly prolonged CPR duration compared to their peers with BMI ≤ 30 kg/m2 (n = 150) and were significantly more likely to require support with VA ECMO (85.7% vs 73.3%, p = 0.015). Survival to hospital discharge was significantly higher in patients with BMI ≤ 30 kg/m2 (48% vs. 29.3%, p < 0.001). BMI was an independent predictor of mortality in a multivariable logistic regression analysis. The four-year mortality rate was low and not significantly different between the two groups (p = 0.32). ConclusionECPR yields clinically meaningful long-term survival in patients with BMI > 30 kg/m2. However, the resuscitation time is significantly prolonged, and the overall survival significantly lower compared to patients with BMI ≤ 30 kg/m2. ECPR should, therefore, not be withheld for this population, but faster transport to an ECMO capable centre is mandated to improve survival to hospital discharge.

CE-454610-1 VENTRICULAR FIBRILLATION REQUIRING EXTRACORPOREAL RESUSCITATION DURING RADIOFREQUENCY ABLATION IN THE CORONARY SINUS

Coronary vasospasm is a rarely reported but potentially catastrophic complication of radiofrequency ablation (RFA). The mechanism is not fully understood but may be related to thermal energy transfer, inflammatory markers released during ablation, and/or alterations in autonomic tone from stimulation of epicardial ganglionated plexi. While most vasospasm occurrences appear subclinical and self-limited, there are exceptions. To highlight an exceptional, life-threatening case of RFA-induced coronary vasospasm. N/A A 62-year-old man with persistent AF and five prior ablations (including one at our institution) presented for ablation of atypical atrial flutter. Termination of the flutter occurred with RFA (7 lesions) at the left atrial roof. There was also a breakthrough of conduction through a prior posterior mitral isthmus line, so coronary sinus (CS) lesions were placed to re-attain mitral block. Two irrigated RF lesions (#1 - 59 seconds, max 26 Watts; #2 - 40 seconds, max 33 Watts) were placed, but 7 seconds into the 3rd lesion (max 27 Watts), ventricular fibrillation (VF) occurred, initially refractory to multiple external shocks. ACLS/CPR commenced. Arterial access was rapidly achieved, and initial coronary angiography simply revealed diffusely slow/no flow related to ongoing VF. Emergent veno-arterial extracorporeal membrane oxygenation (VA ECMO) cannulation was initiated, following which the VF was successfully defibrillated, converting to sinus rhythm. Repeat coronary angiography revealed (known) minimal non-obstructive coronary disease as well as a focal, severe spasm of a dominant left circumflex artery adjacent to the location of CS ablation. Intracoronary nitroglycerin resulted in minimal initial angiographic improvement, so balloon angioplasty and deployment of a drug eluting stent was performed (post: TIMI III flow). The patient made a full recovery and was discharged home on post-procedure day 6 without long-term sequelae. This case underscores a life-threatening complication of RFA within the CS leading to coronary vasospasm and refractory VF. Expedient intervention with extracorporeal resuscitation and support can stabilize patients to allow time to manage arrhythmias and resolve spasm either pharmacologically or procedurally.

PO-05-008 NETWORK META-ANALYSIS OF THE COMPARATIVE EFFICACY OF DOUBLE SEQUENTIAL EXTERNAL, VECTOR-CHANGE, AND STANDARD DEFIBRILLATION FOR REFRACTORY VENTRICULAR FIBRILLATION OUT-OF-HOSPITAL CARDIAC ARREST

Double sequential external defibrillation (DSED; rapid successive shocks from two defibrillators) and vector-change defibrillation (VCD; relocating defibrillation pads anteriorly-posteriorly) have been suggested to enhance clinical outcomes for patients with ventricular fibrillation (VF) refractory of standard defibrillation (SD). This systematic review and network meta-analysis aims to evaluate the comparative efficacy of DSED, VCD, and SD for refractory VF. We conducted a systematic review and network meta-analysis synthesizing randomized controlled trials (RCTs) and comparative observational studies, which were retrieved by systematically searching: PubMed, EMBASE, Web of Science, SCOPUS, and Cochrane through November 15th, 2022. R software netmeta and netrank package (R version 4.2.0) and meta-insight software were used to pool dichotomous outcomes using odds ratio (OR) presented with the corresponding confidence interval (CI). Our protocol was prospectively published in PROSPERO with ID: CRD42022378533. Five retrospective cohorts, one RCT, one pilot RCT, and one case-control study with a total of 1,784 patients were included in our analysis. A total of 439 patients (24.6%) received DSED, 205 patients (11.5%) received VCD, and 1140 patients (n= 63.9%) received SD. In the network meta-analysis, DSED was similar to SD in survival to hospital discharge (OR: 1.14 with 95% CI [0.55, 2.83]), favorable neurological outcome (defined as modified Rankin scale (mRS) or cerebral performance category (CPC) ≤2) (OR: 1.35 with 95% CI [0.46, 3.99]), return of spontaneous circulation (ROSC) (OR: 0.90 with 95% CI [0.53;1.54]), and VF termination (OR: 1.59 with 95% CI [0.92, 2.75]). Also, VCD was similar to SD in survival to hospital discharge (OR: 1.12 with 95% CI [0.27, 4.57]), favorable neurological outcome (OR: 1.01 with 95% CI [0.18, 5.75]), ROSC (OR: 1.06 with 95% CI [0.44, 2.55]), and VF termination (OR: 1.78 with 95% CI [0.95, 3.3]). In the pairwise meta-analysis, there was no difference between DSED and SD in survival to hospital admission (OR: 1.12 with 95% CI [0.58, 2.16]). There was no difference between the use of DSED and VCD compared to SD in patients with out-of-hospital cardiac arrest secondary to refractory VF. However, the current evidence is still not conclusive, warranting further large-scale RCTs.

COVID-19–Mediated Electrical Storm Managed With Milrinone in a Vaccinated Patient

SARS-CoV-2 infection (COVID-19) can lead to an inflammatory response affecting multiple organs. Ventricular arrhythmias, including ventricular tachycardia and ventricular fibrillation (VF), have been reported in otherwise-healthy individuals who have not been vaccinated. A young, otherwise-healthy man who was vaccinated and recently diagnosed with COVID-19 was admitted for refractory VF. Common pharmaceutical agents for VF were given to no avail. VF resolved with use of low-dose milrinone infusion. An inotropic agent usually used in patients with heart failure, milrinone also possesses proven anti-inflammatory effects, which may have allowed it to succeed where the traditional agents failed.