Initial Defibrillator Pad Position and Outcomes for Shockable Out-of-Hospital Cardiac Arrest.

Importance: Ventricular fibrillation (VF) or pulseless ventricular tachycardia (pVT) are the most treatable causes of out-of-hospital cardiac arrest (OHCA). Yet, it remains unknown if defibrillator pad position, placement in the anterior-posterior (AP) or anterior-lateral (AL) locations, impacts patient outcomes in VF or pVT OHCA. Objective: To determine the association between initial defibrillator pad placement position and OHCA outcomes for patients presenting with VF or pVT. Design, Setting, and Participants: This prospective cohort study included patients with OHCA and VF or pVT treated by a single North American emergency medical services (EMS) agency from July 1, 2019, through June 30, 2023. The study included patients with OHCA treated by a large suburban fire-based EMS agency that covers a population of 550 000. Consecutive patients with an initial EMS-assessed rhythm of VF or pVT receiving EMS defibrillation were included. Pediatric patients (younger than 18 years), interfacility transfers, arrests of obvious traumatic etiology, and patients with preexisting do-not-resuscitate status were excluded. Exposure: AP or AL pad placement. Main Outcomes and Measures: Return of spontaneous circulation (ROSC) at any time with secondary outcomes of pulses present at emergency department (ED) arrival, survival to hospital admission, survival to hospital discharge, and functional survival at hospital discharge (cerebral performance category score of 2 or less). Measures included adjusted odds ratios (aOR), multivariable logistic regressions, and Fine-Gray competing risks regression. Results: A total of 255 patients with OHCA were included (median [IQR] age, 66 [55-74] years; 63 females [24.7%]), with initial pad positioning documented as either AP (158 patients [62.0%]; median [IQR] age, 65 [54-74] years; 37 females [23.4%]) or AL (97 patients [38.0%]; median [IQR] age, 66 [57-74] years; 26 females [26.8%]). Patients with AP placement had higher adjusted odds ratio (aOR) of ROSC at any time (aOR, 2.64 [95% CI, 1.50-4.65]), but not significantly different odds of pulses present at ED arrival (1.34 [95% CI, 0.78-2.30]), survival to hospital admission (1.41 [0.82-2.43]), survival to hospital discharge (1.55 [95% CI, 0.83-2.90]), or functional survival at hospital discharge (1.86 [95% CI, 0.98-3.51]). Competing risk analysis found significantly greater cumulative incidence of ROSC among those at risk with initial AP placement compared with AL (subdistribution hazard ratio, 1.81 [95% CI, 1.23-2.67]; P = .003). Conclusions and Relevance: In this cohort study of patients with OHCA and VF or pVT, AP defibrillator pad placement was associated with higher ROSC compared with AL placement.

[Characteristics of electrocardiogram in fulminant myocarditis].

Objective: To investugate the unique electrocardiogram (ECG) characteristics of fulminant myocarditis (FM) patients and provide important clues for the diagnosis of FM. Methods: This was a retrospective study. Patients diagnosed with acute myocarditis at Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology from February 2017 to April 2022 were enrolled and divided into fulminant myocarditis group (FM) and non-fulminant myocarditis group (NFM) according to clinical diagnosis. A total of 246 healthy people who underwent physical examination in the Health examination Center of Tongji Hospital at the same period were selected as the control group. The clinical data and ECG characteristics of the above 3 groups were analyzed and compared. Logistic regression model was used to analyze the influence of ECG parameters on left ventricular ejection fraction in FM patients. Receiver operating curves were constructed to evaluate the predictive value of different ECG parameters for FM. Results: A total of 180 patients were included in this study (FM group: n=123; NFM group: n=57), with an age of (35.0±16.2) years and 106 males (58.89%). Compared with NFM group, ECG was significantly abnormal in FM group, with a higher incidence of sinus tachycardia, ventricular tachycardia or ventricular fibrillation, escape rhythm, right bundle branch block, third degree atrioventricular block, ST-segment elevation, low voltage, prolonged QTc interval, and widened QRS wave in the FM group (all P<0.05). The ECG parameters showed that the amplitude of the full lead QRS wave in FM group was lower than that in NFM group (P<0.01). The average heart rate and QTc interval of FM group were significantly higher than those of NFM and control groups (all P<0.05). Although ST-segment elevation had a higher incidence in the FM group, ECG parameters showed that except for leads Ⅲ and aVF, the ST segment levels in all leads in the FM group were lower than those in the control group (all P<0.05). There was a statistically significant difference in some ST segment changes between FM and NFM groups, while there was no statistical difference between the NFM and control groups. Multivariate regression analysis showed that widened QRS wave and increased heart rate were the influencing factors for left ventricular systolic dysfunction in FM patients (OR=16.914, 95%CI: 1.367-209.224, P=0.028; OR=1.026, 95%CI: 1.010-1.042, P=0.001). Receiver operating curve analysis showed that heart rate>86.90 beat/min, QTc>431.50 ms, and RV5+SV1<1.72 mV had certain predictive value for FM diagnosis. Conclusions: FM patients displayed marked and severe ECG abnormalities, and characteristic changes in ECG can provide important first clues for the diagnosis of FM.

Development of artificial intelligence-driven biosignal-sensitive cardiopulmonary resuscitation robot.

AIM OF THE STUDY: We evaluated whether an artificial intelligence (AI)-driven robot cardiopulmonary resuscitation (CPR) could improve hemodynamic parameters and clinical outcomes. METHODS: We developed an AI-driven CPR robot which utilizes an integrated feedback system with an AI model predicting carotid blood flow (CBF). Twelve pigs were assigned to the AI robot group (n = 6) and the LUCAS 3 group (n = 6). They underwent 6 min of CPR after 7 min of ventricular fibrillation. In the AI robot group, the robot explored for the optimal compression position, depth and rate during the first 270-second period, and continued CPR with the optimal setup during the next 90-second period and beyond. The primary outcome was CBF during the last 90-second period. The secondary outcomes were coronary perfusion pressure (CPP), end-tidal carbon dioxide level (ETCO2) and return of spontaneous circulation (ROSC). RESULTS: The AI model's prediction performance was excellent (Pearson correlation coefficient = 0.98). CBF did not differ between the two groups [estimate and standard error (SE), -23.210 ± 20.193, P = 0.250]. CPP, ETCO2 level and rate of ROSC also did not show difference [estimate and SE, -0.214 ± 7.245, P = 0.976 for CPP; estimate and SE, 1.745 ± 3.199, P = 0.585 for ETCO2; 5/6 (83.3%) vs. 4/6 (66.7%), P = 1.000 for ROSC). CONCLUSION: This study provides proof of concept that an AI-driven CPR robot in porcine cardiac arrest is feasible. Compared to a LUCAS 3, an AI-driven CPR robot produced comparable hemodynamic and clinical outcomes.

Defibrillation strategies for patients with refractory ventricular fibrillation: A systematic review and meta-analysis.

AIM: The aim of this study was to summarize the existing evidence about the effectiveness of double defibrillation (DD) in comparison to standard defibrillation for patients with refractory ventricular fibrillation (RVF). DD encompasses double "sequential" external defibrillation (DSeq-D) and double "simultaneous" defibrillation (DSim-D), with the study also shedding light on the respective effects of DSeq-D and DSim-D. METHODS: Investigators systematically searched PubMed, EMBASE and Cochrane Central databases for randomized controlled trials (RCTs) and cohort studies from their inception until June 06, 2024. The rate of survival to hospital discharge was the primary outcome, while the incidence of return of spontaneous circulation (ROSC), termination of ventricular fibrillation (VF), survival to hospital admission and good neurologic outcome were secondary outcomes. Relative ratios (RR) and 95% confidence intervals (CIs) were calculated for each outcome. Heterogeneity was assessed using I square value. RESULTS: A total of 6 trials, comprising 1360 patients, were included. One was an RCT, and five were observational cohort studies. The RCT showed that, compared to standard defibrillation, DSeq-D was associated with higher incidences of survival to hospital discharge, termination of VF, ROSC and good neurologic outcome. However, the pooled results of cohort studies found no benefit of DD over standard defibrillation in survival to hospital discharge (RR, 0.91; 95% CI, 0.46-1.78), nor in secondary outcomes. Furthermore, subgroup analysis suggested DSim-D was linked with lower ROSC rate compared to standard defibrillation (RR, 0.65; 95% CI, 0.49-0.86), while there was no significance between DSeq-D and standard defibrillation (RR, 1.00; 95% CI, 0.70-1.42). CONCLUSIONS: The benefit of DSeq-D in survival to hospital discharge for RVF patients was found in the RCT, but not in cohort studies. Additionally, DSim-D should be applied with greater caution for RVF patients. Further validation is needed through larger-scale and higher-quality trials. TRIAL REGISTRY: INPLASY; Registration number: INPLASY202340015; URL: https://inplasy.com/.

Ventricular arrhythmias and primary prevention of sudden cardiac death in Anderson-Fabry disease.

The Anderson-Fabry disease (AFD) is a X-linked lysosomal storage disorder due to the deficiency in the α-galactosidase A enzyme. Cardiovascular mortality is a major cause of death in patients with AFD and sudden cardiac death (SCD) is one of the main causes of death. The storage of glycosphingolipid along with ionic channel impairment, inflammation and fibrosis are involved in the arrhythmogenesis. Some risk factors have been associated with ventricular tachycardia (VT)/ventricular fibrillation (VF) and SCD. Left ventricular hypertrophy (LVH), cardiac fibrosis, non-sustained VTs seem to be the most important. Older age and male gender might be associated with higher risk of ventricular arrhythmias and SCD. Currently, the implantable cardioverter-defibrillator (ICD) is recommended in patients with AFD who have survived a cardiac arrest secondary to VT/VF or who experienced sustained VT causing syncope or hemodynamic compromise, and have a life expectancy >1 year. ICD implantation is also recommended in patients considered to be at high risk (e.g., patients with severe LVH or fibrosis). The present review sought to summarize the risk of ventricular arrythmias in AFD, the indications for ICD, focusing on pathophysiology and analyzing the role of possible predictors of arrhythmias in preventing SCD, especially as primary prevention.

Substrate Characterization and Outcomes of Ventricular Tachycardia Ablation in Amyloid Cardiomyopathy: A Multicenter Study.

BACKGROUND: Sustained ventricular tachycardia (VT) in cardiac amyloidosis is uncommon, and the substrate and outcomes of catheter ablation are not defined. METHODS: We included 22 consecutive patients (mean age, 68±10 years; male sex, 91%) with cardiac amyloidosis (ATTR [transthyretin], n=16; light chain, n=6) undergoing catheter ablation for VT/ventricular fibrillation (VF) between 2013 and 2023 in a retrospective, observational, international study. The primary efficacy outcome was recurrent VT/VF during follow-up, while the primary safety end point included major procedure-related adverse events. RESULTS: The indication for ablation was drug-refractory VT in 17 patients (77%), and premature ventricular complex-initiated polymorphic VT/VF in 5 patients (23%). Catheter ablation was performed using endocardial (n=17.77%) or endo-epicardial approaches (n=5.23%). Complete endocardial electroanatomical voltage maps of the left and right ventricles were obtained in 17 (77%) and 10 (45%) patients, respectively. Each patient had evidence of low-voltage areas, most commonly involving the interventricular septum (n=16); late potentials were recorded in 16 patients (73%). A median of 1 (1-2) VT was inducible per patient; 12 of the 26 mappable VTs (46%) originated from the interventricular septum. Complete procedural success was achieved in 16 patients (73%), with 4 (18%) major procedure-related adverse events. After a median follow-up of 32 (14-42) months, sustained VT/VF recurrence was observed in 9 patients (41%); survival free from VT/VF recurrence was 56% (95% CI, 36%-86%) at 36-month follow-up, and most patients remained on antiarrhythmic drugs. A significant reduction in per patient implantable cardioverter defibrillator therapies was noted in the 6-month period after ablation (before: 6 [4-9] versus after: 0 [0-0]; P<0.001). In multivariable analysis, complete procedural success was associated with reduced risk of recurrent VT/VF (hazard ratio, 0.002; P=0.034). CONCLUSIONS: Catheter ablation can achieve control of recurrent VT/VF in more than half of patients with cardiac amyloidosis, and the reduction in VT/VF burden post-ablation may be relevant for quality of life. Septal substrate and risk of procedure-related complications challenge successful management of patients with cardiac amyloidosis and VT/VF.

Ventricular arrhythmias in the context of chronic kidney disease and electrolyte imbalance.

Patients with chronic kidney disease face a high risk of sudden cardiac death, particularly in more advanced stages of renal dysfunction. Ventricular arrhythmias are prevalent and contribute to the heightened cardiovascular mortality. This review aims to explore the intricate interplay of disease-specific risk factors, arrhythmic triggers, and electrolyte disorders that amplify susceptibility to ventricular arrhythmias and sudden cardiac death in this population and influence the efficacy of available treatments.

First human safety and effectiveness study of defibrillation with a novel patch wearable cardioverter-defibrillator.

AIMS: Wearable cardioverter-defibrillators (WCDs) are indicated in patients at risk of sudden cardiac arrest who are not immediate candidates for implantable defibrillator therapy. Limitations of existing WCDs include poor compliance and high false alarm rates. The Jewel is a novel patch-WCD (P-WCD) that addresses these limitations with an adhesive-based design for near-continuous wear and a machine learning algorithm designed to minimize inappropriate detections. This was a first-in-human study of the Jewel P-WCD conducted in an electrophysiology (EP) lab to determine the safety and effectiveness of the device in terminating ventricular tachycardia/ventricular fibrillation (VT/VF) with a single shock. The aim was to evaluate the safety and effectiveness of terminating VT/VF with a single shock using the Jewel P-WCD. METHODS AND RESULTS: This was a first-in-human, prospective, single-arm, single-centre study in patients scheduled for an EP procedure in which VT/VF was expected to either spontaneously occur or be induced. The Jewel P-WCD was placed on consented patients; upon confirmation of VT/VF, a single shock (150 J) was delivered via the device. A group sequential design and Pocock alpha spending function was used to measure the observed proportion of successful VT/VF single-shock terminations. The endpoint was achieved if the lower confidence limit exceeded the performance goal of 62%, using a one-sided lower 97.4% exact confidence bound. Of 18 eligible subjects, 16 (88.9%, 97.4% confidence bound: 65.4%) were successfully defibrillated with a single shock, exceeding the primary endpoint performance goal with no adverse events. CONCLUSION: This first-in-human evaluation of the Jewel P-WCD demonstrated the safety and effectiveness of terminating VT/VF. CLINICAL TRIAL REGISTRATION: URL: https://clinicaltrials.gov/; Unique identifier: NCT05490459.

Combined Stellate Ganglion Blockade and Epidural Thoracic Anesthesia for the Management of Ventricular Storm: A Case Report.

ABSTRACT: The term "ventricular storm (VS)" is defined as the occurrence of two or more separate episodes of ventricular tachycardia or fibrillation (VT/VF) or three or more appropriate discharges of an implantable cardioverter defibrillator for VT/VF during a 24-h period. A patient in his early 40s was observed in the emergency department of our hospital and was admitted to the cardiac intensive care unit due to multiple episodes of VT. This led to the need for deep sedation with orotracheal intubation and mechanical ventilation. Intravenous lidocaine treatment was started; however, the patient had a recurrence of the episodes of VT. We decided to combine stellate ganglion block with epidural thoracic anesthesia. After the sympathetic block, there was no recurrence of the arrhythmic episodes. The patient was then transferred for ablation treatment. We demonstrated the efficacy of both techniques in managing a patient with multiple episodes of ventricular storm.

Extracorporeal Membrane Oxygenation for Protected Catheter Ablation in A Post-Cardiotomy Patient With Electrical Storm.

ABSTRACT: An electrical storm (ES) refers to multiple occurrences of ventricular arrhythmias within a short time. Catheter ablation is a treatment option for ES but can be challenging in unstable cardiovascular patients. We present the case of a 50-year-old patient with poor left ventricular function who experienced ES after emergency coronary artery bypass grafting (CABG). Despite maximal antiarrhythmic therapy, the patient had recurrent ventricular tachycardia and fibrillation (VT/VF), hindering catheter ablation. Elective venoarterial extracorporeal membrane oxygenation (ECMO) support was established, allowing a successful second catheter ablation attempt without complications. The patient was weaned off ECMO the following day and remained in normal sinus rhythm.

Active decompression during automated head-up cardiopulmonary resuscitation.

BACKGROUND: The combination of active compression-decompression cardiopulmonary resuscitation (ACD-CPR) with an impedance threshold device (ITD) and controlled head-up positioning (AHUP-CPR) is associated with improved outcomes compared with conventional CPR (C-CPR). This study focused on the role of active decompression (AD) during AHUP-CPR. METHODS: Farm pigs (n = 10, ∼40 kg) were anesthetized, intubated and ventilated. Physiological parameters and right ventricular pressure-volume loops were recorded continuously. Ventricular fibrillation was induced and left untreated for 10 mins, followed by automated C-CPR (2 min), ACD + ITD CPR in the flat position (2 min), and then AHUP-CPR with 3 cm of lift above the neutral chest position. After 15 min of CPR, AD was discontinued and then restarted incrementally to 4 cm. Data were analyzed with a linear mixed-effects model, using random intercepts for individual pigs. RESULTS: Upon cessation of AD during AHUP-CPR, decompression right atrial pressure (+59%) increased (p < 0.01), whereas multiple hemodynamic parameters positively associated with perfusion, including coronary (-25%) and cerebral perfusion pressures (-11%), end-tidal CO2 (-13%), stroke volume and cardiac output (-26%), decreased immediately and significantly with p < 0.05. Restoration of AD reduced right atrial pressure and increased positive perfusion parameters in an incremental manner. Only with ≥ 3 cm of AD were all hemodynamic parameters restored to ≥ 90% of pre-AD discontinuation levels. CONCLUSION: Full chest wall lift, achieved with ≥ 3 cm of AD, was needed to maintain and optimize hemodynamics during AHUP-CPR in pigs. These findings should be considered when optimizing care with this new approach.

A Patch Wearable Cardioverter-Defibrillator for Patients at Risk of Sudden Cardiac Arrest.

BACKGROUND: For many patients, sudden cardiac arrest (SCA) risk is elevated temporarily. Wearable cardioverter-defibrillators (WCDs) can monitor and treat SCA during these temporary periods. Traditional WCDs can be uncomfortable, require frequent maintenance, and cannot be used when showering, resulting in poor compliance and avoidable SCA deaths. The Jewel is a novel, water-resistant patch-wearable cardioverter-defibrillator (P-WCD) with a machine learning detection algorithm designed to improve compliance and protection against SCA. OBJECTIVES: This study aims to demonstrate the safety and clinical effectiveness of a novel P-WCD. METHODS: The Jewel IDE Study, a prospective, single-arm study conducted at 30 U.S. sites, enrolled patients at SCA risk due to ventricular tachycardia/ventricular fibrillation who were not candidates for or refused an implantable defibrillator. The primary safety endpoint was <15% patients with clinically significant cutaneous adverse device effects and the primary effectiveness endpoint was <2 inappropriate shocks/100 patient-months. Secondary endpoints were ≥1 successful ventricular tachycardia/ventricular fibrillation conversion and wear time compliance of >14.1 h/d. RESULTS: A total of 305 patients (mean age: 57.9 years; 30.2% female, 27.9% non-White) were enrolled, of which 290 had available device data. The clinically significant cutaneous adverse device effect rate was 2.30% (upper 1-sided 98% CI: 4.80); none were severe. No device-related deaths or serious adverse events were reported. The inappropriate shock rate was 0.36/100 patient-months (upper 1-sided 98% CI: 1.53). Of 11 shocks in 9 patients, 9 shocks were adjudicated to be appropriate. Eight of 9 shocks were successful with a single shock. Median wear time compliance was 23.5 (20.7-23.9) h/d. CONCLUSIONS: The novel P-WCD is a safe and effective WCD with high patient compliance. There were no deaths due to noncompliance and a high number of successful conversions (Jewel IDE study [A Clinical Evaluation of the Jewel P-WCD in Subjects at High Risk for Sudden Cardiac Arrest]; NCT05201495).

A case of early repolarization syndrome in which hyponatremia and coronary vasospasms induced ventricular fibrillation.

A 60-year-old man was referred to our hospital presenting with unconsciousness due to severe hyponatremia. The twelve­lead ECG on admission exhibited prominent J waves in the inferolateral leads. During the treatment for hyponatremia, ventricular fibrillation (VF) occurred and the electrogram (ECG) after the VF incident exhibited marked ST elevation in the inferolateral leads. An Ach provocation test induced vasospasms in the right and left coronary arteries and J wave augmentation, suggesting a high risk for vasospastic angina. Finally, a subcutaneous implantable cardioverter defibrillator was implanted in the patient. We hereby discuss the possible contribution of hyponatremia to VF episodes in early repolarization syndrome based on the present case.

Mode and Characteristics of Arrhythmia Initiation in Idiopathic Ventricular Fibrillation: A THESIS Substudy.

BACKGROUND: There is limited information on the mode of arrhythmia initiation in idiopathic ventricular fibrillation (IVF). A non-pause-dependent mechanism has been suggested to be the rule. OBJECTIVES: The aim of this study was to assess the mode and characteristics of initiation of polymorphic ventricular tachycardia (PVT) in patients with short or long-coupled PVT/IVF included in THESIS (THerapy Efficacy in Short or long-coupled idiopathic ventricular fibrillation: an International Survey), a multicenter study involving 287 IVF patients treated with drugs or radiofrequency ablation. METHODS: We reviewed the initiation of 410 episodes of ≥1 PVT triplet in 180 patients (58.3% females; age 39.6 ± 13.6 years) with IVF. The incidence of pause-dependency arrhythmia initiation (prolongation by >20 ms of the preceding cycle length) was assessed. RESULTS: Most arrhythmias (n = 295; 72%) occurred during baseline supraventricular rhythm without ambient premature ventricular complexes (PVCs), whereas 106 (25.9%) occurred during baseline rhythm including PVCs. Nine (2.2%) arrhythmias occurred during atrial/ventricular pacing and were excluded from further analysis. Mode of PVT initiation was pause-dependent in 45 (15.6%) and 64 (60.4%) of instances in the first and second settings, respectively, for a total of 109 of 401 (27.2%). More than one type of pause-dependent and/or non-pause-dependent initiation (mean: 2.6) occurred in 94.4% of patients with ≥4 events. Coupling intervals of initiating PVCs were <350 ms, 350-500 ms, and >500 ms in 76.6%, 20.72%, and 2.7% of arrhythmia initiations, respectively. CONCLUSIONS: Pause-dependent initiation occurred in more than a quarter of arrhythmic episodes in IVF patients. PVCs having long (between 350 and 500 ms) and very long (>500 ms) coupling intervals were observed at the initiation of nearly a quarter of PVT episodes.

Fascicular Substrate Modification to Treat Human Ventricular Fibrillation.

BACKGROUND: Purkinje fibers play an important role in initiation and maintenance of ventricular fibrillation (VF) and polymorphic ventricular tachycardia (PMVT). Fascicular substrate modification (FSM) approaches have been suggested to treat recurrent VF in case reports and small case series. OBJECTIVES: The aim of this study was to investigate outcomes of catheter-based FSM to treat VF and PMVT. METHODS: Of 2,212 consecutive patients with ventricular arrhythmia undergoing catheter ablation, 18 (0.81%) underwent FSM of the Purkinje fibers as identified with high-density mapping during sinus rhythm. Fascicular substrate and VF initiation were mapped using a multipolar catheter. The endpoint of the ablation was noninducibility of VF and PMVT. In select patients, remapping revealed elimination of the targeted Purkinje potentials. Demographic, clinical, and follow-up characteristics were prospectively collected in our institutional database. RESULTS: A total of 18 patients (mean age 56 ± 3.8 years, 22% women) were included in the study. Of those, 11 (61.1%) had idiopathic VF, 3 (16.7%) had nonischemic cardiomyopathy, and 4 (22.2%) had mixed cardiomyopathy. The average left ventricular ejection fraction was 42.5%. At least 2 antiarrhythmic drugs had failed preablation. At baseline, all patients had inducible VF or PMVT. At the end of the procedure, no patient demonstrated new evidence of fascicular block or bundle branch block. There were no procedure-related complications. After a median follow-up period of 24 months, 16 patients (88.9%) were arrhythmia free on or off drugs: 11 of 11 patients (100%) with idiopathic VF vs 5 of 7 patients (71.4%) with underlying cardiomyopathy (P = 0.06). CONCLUSIONS: Catheter ablation of human VF and PMVT with FSM is feasible and safe and appears highly effective, with high rates of acute VF noninducibility and long-term freedom from recurrent VF.

Landiolol for refractory ventricular fibrillation in out-of-hospital cardiac arrest: A randomized, double-blind, placebo-controlled, pilot trial.

BACKGROUND: Out-of-hospital cardiac arrest (OHCA) complicated by refractory ventricular fibrillation (VF) is associated with poor outcome. Beta-1-receptor selective blockade might overcome refractory VF and improve survival. This trial investigates the efficacy and safety of prehospital landiolol in OHCA and refractory VF. METHODS: In this randomized, double-blind, placebo-controlled pilot trial, patients with OHCA and recurrent or refractory VF (at least 3 defibrillation attempts and last rhythm shockable), pretreated with epinephrine and amiodarone, were allocated to receive add-on treatment with landiolol or placebo. Landiolol was given as a 20 mg bolus infusion. The primary efficacy outcome was time from trial drug infusion to sustained return of spontaneous circulation (ROSC). Safety outcomes included the onset of bradycardia and asystole. RESULTS: A total of 36 patients were enrolled, 19 were allocated to the landiolol group and 17 to the placebo group. Time from trial drug infusion to sustained ROSC was similar between treatment groups (39 min [landiolol] versus 41 min [placebo]). Sustained ROSC was numerically lower in the landiolol group compared with the placebo group (7 patients [36.8%] versus 11 patients [64.7%], respectively). Asystole within 15 min of trial drug infusion occurred significantly more often in the landiolol group than in the placebo group (7 patients [36.8%] and 0 patients [0.0%], respectively). CONCLUSION: In patients with OHCA and refractory VF who are pretreated with epinephrine and amiodarone, add-on bolus infusion of landiolol 20 mg did not lead to a shorter time to sustained ROSC compared with placebo. Landiolol might be associated with bradycardia and asystole.

The impact of time to defibrillation on return of spontaneous circulation in out-of-hospital cardiac arrest patients with recurrent shockable rhythms.

OBJECTIVE: Optimal timing for subsequent defibrillation attempts for Out-of-hospital cardiac arrest (OHCA) patients with recurrent VF/pVT is uncertain. We investigated the relationship between VF/pVT duration and return of spontaneous circulation (ROSC) in OHCA patients with recurrent shockable rhythms. METHODS: We analyzed data from the Salt Lake City Fire Department (SLCFD) spanning from 2012 to 2023. The implementation of rhythm-filtering technology since 2011 enabled real-time rhythm interpretation during CPR, with local protocols allowing early defibrillation for recurrent/refractory VF/pVT cases. We included patients experiencing four or five episodes of VF and pVT rhythms and employed generalized estimating equation (GEE) regression analysis to examine the association between VF/pVT durations preceding recurrent defibrillation and return of spontaneous circulation (ROSC). RESULTS: Analysis of 622 appropriate shocks showed that patients achieving ROSC had significantly shorter median VF/pVT duration than those who did not achieve ROSC (0.83 minutes vs. 1.2 minutes, p = 0.004). Adjusted analysis of those with 4 VF/pVT episodes (N = 142) revealed that longer VF/pVT durations were associated with lower odds of achieving ROSC (odds ratio: 0.81, 95% CI: 0.72-0.93, p = 0.005). Every one-minute delay in intra-arrest defibrillation is predicted to decrease the likelihood of achieving ROSC by 19%. CONCLUSION: Every one-minute increase in intra-arrest VF/pVT duration was associated with a statistically significant 19% decrease in the chance of achieving ROSC. This highlights the importance of reducing time to shock in managing recurrent VF/pVT. The findings suggest reevaluating the current recommendations of two minutes intervals for rhythm check and shock delivery.

Observable Atrial and Ventricular Fibrillation Episode Durations Are Conformant With a Power Law Based on System Size and Spatial Synchronization.

BACKGROUND: Atrial fibrillation (AF) and ventricular fibrillation (VF) episodes exhibit varying durations, with some spontaneously ending quickly while others persist. A quantitative framework to explain episode durations remains elusive. We hypothesized that observable self-terminating AF and VF episode lengths, whereby durations are known, would conform with a power law based on the ratio of system size and correlation length ([Formula: see text]. METHODS: Using data from computer simulations (2-dimensional sheet and 3-dimensional left-atrial), human ischemic VF recordings (256-electrode sock, n=12 patients), and human AF recordings (64-electrode basket-catheter, n=9 patients; 16-electrode high definition-grid catheter, n=42 patients), conformance with a power law was assessed using the Akaike information criterion, Bayesian information criterion, coefficient of determination (R2, significance=P<0.05) and maximum likelihood estimation. We analyzed fibrillatory episode durations and [Formula: see text], computed by taking the ratio between system size ([Formula: see text], chamber/simulation size) and correlation length (xi, estimated from pairwise correlation coefficients over electrode/node distance). RESULTS: In all computer models, the relationship between episode durations and [Formula: see text] was conformant with a power law (Aliev-Panfilov R2: 0.90, P<0.001; Courtemanche R2: 0.91, P<0.001; Luo-Rudy R2: 0.61, P<0.001). Observable clinical AF/VF durations were also conformant with a power law relationship (VF R2: 0.86, P<0.001; AF basket R2: 0.91, P<0.001; AF grid R2: 0.92, P<0.001). [Formula: see text] also differentiated between self-terminating and sustained episodes of AF and VF (P<0.001; all systems), as well as paroxysmal versus persistent AF (P<0.001). In comparison, other electrogram metrics showed no statistically significant differences (dominant frequency, Shannon Entropy, mean voltage, peak-peak voltage; P>0.05). CONCLUSIONS: Observable fibrillation episode durations are conformant with a power law based on system size and correlation length.

Implantable Cardioverter-Defibrillator Placement in Spontaneous Coronary Artery Dissection: A Case Report.

BACKGROUND Spontaneous coronary artery dissection can present with acute coronary syndrome, ventricular arrhythmias, or sudden cardiac death. Implantable cardioverter-defibrillator placement in patients with spontaneous coronary artery dissection is controversial. The purpose of publishing this case is to inform physicians of potential benefits of implantable cardioverter-defibrillator implantation in patients with spontaneous coronary artery dissection. CASE REPORT A 55-year-old woman presented with chest pain, with an electrocardiogram revealing anterior ST-elevation myocardial infarction and troponin peak of 53.8 ng/mL. Coronary angiography revealed mid-left anterior descending artery occlusion, with appearance of spontaneous coronary artery dissection that was not amenable to revascularization. The decision was made to treat medically. In recovery, the patient experienced ventricular fibrillation arrest. The patient was defibrillated once with achievement of return of spontaneous circulation. An Impella CP was placed to stabilize the patient. After the patient was stabilized, an implantable cardioverter-defibrillator was placed. CONCLUSIONS Data on potential benefits of implantable cardioverter-defibrillator placement in patients with spontaneous coronary artery dissection are limited. Most patients with spontaneous coronary artery dissection recover normal coronary architecture; however, there are no guidelines for implantable cardioverter-defibrillator placement in patients with spontaneous coronary artery dissection. Patients with spontaneous coronary artery dissection with high-risk features may benefit from implantable cardioverter-defibrillator for secondary prevention of ventricular arrhythmia and sudden cardiac death, as shown with this case.