Ventricular fibrillation amplitude spectral area as a guide to deliver the optimal energy level for defibrillation

Introduction

In case of cardiac arrest due to ventricular fibrillation (VF) or pulseless ventricular tachycardia (pVT), the optimal energy should be the lowest energy effective to achieve defibrillation minimizing the current-induced myocardial damage. Therefore, it would be ideal to minimize the energy level as well as the number of shocks during resuscitation. ECG-based VF waveform analysis features such as amplitude spectral area have been recently introduced as predictors of shock success, but their predictivity for shock success with low energy level is not known.

Purpose

To assess whether amplitude spectral area (AMSA) of VF is able to predict the efficacy of low energy level defibrillation in out-of-hospital cardiac arrest (OHCA) patients.

Methods

All the OHCAs with at least one shockable rhythm that occurred from January 2015 to December 2020 were considered. AMSA values were calculated by retrospectively analyzing the data collected by the Corpuls 3 monitors/defibrillators and by using a 2-second-pre-shock ECG interval.

Results

Among 4619 OHCAs, resuscitation was attempted in 2982 (64%) and at least one shock was delivered in 697 (15%). AMSA values and defibrillation energy were available for 791 shocks, of which 45% received shock at low energy (>150J) and 55% at high energy (>150J). The rate of efficacy between the two groups was similar (44% vs 38%, p=0.102). However, in patients efficaciously treated with shock at low energy, AMSA was higher compared to those treated with shock at high energy [13.2 mV Hz (IQR 10.2–17) vs 10.8 mV Hz (IQR 8–13.8), p<0.001]. Moreover, AMSA values were significantly different when comparing ineffective shock at low energy with effective shock at high energy [6.6 mV Hz (IQR 4.6–10) vs 10.8 mV Hz (IQR 8.1–13.8), p<0.001] and similar when comparing ineffective shock at low and high energy [6.6 mV Hz (IQR 4.6–10) vs 6.3 mV Hz (IQR 4.5–8.7), p=0.21]. By dividing AMSA values into three tertiles, the rate of shock success at low energy was statistically different: [T1 (0.7–6.2 mV Hz) 4.2%; T2 (6.2–10.8 mV Hz) 13%; T3 (10.8–63.2 mV Hz) 42%; Chi-squared p<0.001 and p for trend <0.001]. After correction for age, sex, amiodarone use and call to shock time, AMSA values corresponding to the third and second tertile were associated with higher probability of shock success at low energy compared to the lowest tertile [T3 OR 15 (95% CI 7–30), p<0.001; T2 OR 3 (95% CI 1–7), p=0.002].

Conclusion

Ventricular fibrillation amplitude spectral area is a predictor of shock success at a low energy level. This could be useful to optimize both time and dose-energy to patients, yielding the highest chance for successful defibrillation while reducing the number of futile shocks and thus limiting the total current myocardial energy as well as CPR interruptions.

Funding Acknowledgement

Type of funding sources: None.

Gender differences in amplitude spectral area (AMSA) of ventricular fibrillation in patients with out-of-hospital cardiac arrest

Introduction

Ventricular fibrillation (VF) Amplitude Spectral Area (AMSA) is a well-established predictor of successful defibrillation and return of spontaneous circulation (ROSC). Attending to the limited evidence on the topic, gender seems to affect AMSA, and higher values have been reported in females. The aim of this work was to investigate the effect of gender in AMSA values for patients suffering out-of-hospital cardiac arrest (OHCA).

Methods

We enrolled 4619 consecutive OHCA patients from January 2015 to December 2020 in the LombardiaCare Registry. We considered only those subjects with attempted cardio-pulmonary resuscitation (697 patients) and at least one shock delivered. A total of 250 patients were considered (40 F/ 210 M) with 830 shocks (100 F/ 730 M). AMSA values were computed for the ventricular fibrillation in the 2-s pre-shock interval of the ECG recorded by the Corpuls3 defibrillator (Corpuls, Kaufering, Germany).

Results

Female patients were older than male [median (IQR): 70.5 (62–72) vs 67 (55–75) years, p=0.01], with cardiac arrest more frequently at home (84% vs 76%, p=0.003), fewer shocks [2 (1–4) vs 4 (2–7), p=0.004] and higher percentage of success (53% vs 40%, p=0.009). On the contrary, cardiac arrest duration [ 58.7 (31–69) vs 57.6 (41.4–77.3) min, p=0.366] and the rate of ROSC (32% vs 33%, p=0.88) were similar in both groups.

Higher AMSA values were found in female patients [10.3 Hz-mV (6.6–13.5) vs 7.9 Hz-mV (5.2–12.1), p=0.0007]. At a multivariable analysis, after correction for witnessed status, bystanders CPR, amiodarone administration, age and call-to shock time, male sex was found to be independently associated with the probability of having low values of AMSA, below the median value of 8.3 Hz-mV [OR 2.15 (95% CI1.35–3.43), p=0.001].

Despite gender stratification ROC curve analysis confirmed AMSA as a predictor of shock success [AUC-F: 0.75 (95% CI 0.65–0.83), p<0.001; AUC-M: 0.78 (95% CI 0.74–0.81)] and ROSC [AUC-F: 0.69 (95% CI 0.59–0.68), p=0.008; AUCM: 0.84 (95% CI 0.81–0.87)].

Conclusion

Female sex is related to higher AMSA values. As AMSA reflects the energetical status and the ATP levels in the myocardial cells during cardiac arrest, this difference may be due to lower incidence and lower severity of cardiac ischemic disease in women. AMSA remains a valid predictor of both shock success and ROSC for female and male patients. Further investigations are needed to support and comprehend these conclusions.

Funding Acknowledgement

Type of funding sources: None.

Amiodarone and ventricular fibrillation amplitude of spectral area in patients with out-of-hospital cardiac arrest. Is there an effect?

Background

The use of antiarrhythmic drug therapy is usually recommended in addition to defibrillation in shockable cardiac arrest. The role of the amplitude spectral area (AMSA) of ventricular fibrillation as a predictor of defibrillation efficacy has been established, but little is known about how amiodarone could affect AMSA values.

Purpose

The aim of our study was to evaluate whether the administration of amiodarone during resuscitation could affect AMSA and to verify if AMSA preserves its predictive role of shock success in OHCA patients treated with amiodarone.

Material

All the OHCAs with an attempted resuscitation and at least one shockable rhythm which occurred from January 2015 to December 2020 in the province of Pavia were considered. AMSA values were calculated by retrospectively analyzing the data collected by the Corpuls 3 monitors/defibrillators (Corpuls, Kaufering, Germany) used in the field and by considering a pre-shock interval of 2 seconds.

Results

Of 4619 OHCAs, 697 underwent attempted CPR with at least one shock delivered. Of these, AMSA was available on 250 patients (male 84%, median age 67 years), for a total of 830 shocks, of which 534 (64%) shocks were in patients receiving amiodarone. The success rate of each single shock was similar in the two groups (amiodarone 42% vs no amiodarone 41%, p=0.68). The AMSA median values were significantly lower in the amiodarone group as compared to the non-amiodarone group when shocks were delivered to patients older than 67 years old [median difference: 1.55 mV Hz (95% CI 0.6–2.5), p=0.0013] or receiving bystander CPR [median difference 0.9 mV Hz (95% CI 0.1–1.8), p=0.03] or after more than 33 minutes from the emergency call to each single shock [median difference: 0.91 mV Hz (95% CI 1.9–0.01), p=0.047]. AMSA value lower than the median (8.3 Hz mV) was associated with a lower probability of shock success (19% vs 64%, p<0.001). According to a multivariate analysis corrected for age, sex, witnessed status, call to shock time and bystander CPR, the probability of having AMSA lower than the median was independently associated with the administration of amiodarone [OR 1.5 (95% CI 1.1–2.1) p=0.009]. At ROC curves analysis, amongst patients receiving amiodarone, AMSA was confirmed to be a predictor of both shock success and ROSC [AUC 0.755 (95% CI 0.72–0.79), p<0.001 and AUC 0.826 (95% CI 0.79–0.86), p<0.001 respectively], similarly to the general population [AUC 0.778 (95% CI0.75–0.81), p<0.001; AUC 0.817 (95% CI 0.79–0.84), p<0.001].

Conclusions

Amiodarone administration is independently associated with lower values of AMSA. This could justify the lack of benefit from amiodarone administration in term of defibrillation success which would be expected by the administration of an antiarrhythmic drug during the resuscitation. Moreover, AMSA maintains its predictive value for shock success and ROSC rate in patients receiving amiodarone as well as in the general population.

Funding Acknowledgement

Type of funding sources: None.

Impact of gender on survival of out-of-hospital cardiac arrest presenting with refractory ventricular arrhythmias and role of coronary artery disease

Funding Acknowledgements

Type of funding sources: None.

Introduction

Clinical presentation and outcome of out-of-hospital cardiac arrest (OHCA) presenting with shockable rhythm may vary between males and females. Very limited data exist on gender-related differences in OHCAs with refractory ventricular arrhythmias (VA) and, in particular, on distribution and prevalence of coronary artery disease (CAD).

Purpose

The aim of this study was to characterize gender-related outcome, prevalence and severity of CAD in OHCA victims presenting with shockable rhythm and refractory VA.

Methods

All OHCAs presenting with shockable rhythm occurred between 2015 and 2019 in the province of Pavia (Italy) and in the Canton Ticino (Switzerland) were included.

Results

Out of 3592 OHCAs, 685 presented with shockable rhythm and, of them, 212 had a refractory VA. Overall, male gender was independently associated with a lower probability of survival both at hospital admission and at 30-days (OR 0.63, 95% CI 0.58-0.67, p <0.001 and OR 0.82 95% CI 0.74-0.91, p <0.001, respectively) and presented with a more severe CAD. Male gender was 5-times more frequently associated with OHCA presenting with refractory VA. Despite of a more favourable OHCA presentation (i.e. more often OHCA witnessed, public place occurrence and CPR initiated by bystander) male patients with refractory VA had a lower likelihood of survival (OR 0.25, 95% CI 0.21-0.30). A higher prevalence (81%) of CAD was observed in OHCAs presenting with refractory VA but not a higher number of diseased vessels.

Conclusions

Male gender is more frequently associated with refractory VA, lower probability of survival and higher prevalence and severity of CAD. CAD severity, however, does not significantly affect refractory VA presentation.

C8 THE CEREBRAL PERFORMANCE CATEGORY IN THE DECISION–MAKING PROCESS OF IMPLANTING AN ICD IN OUT–OF–HOSPITAL CARDIAC ARREST SURVIVORS WITH BAD NEUROLOGICAL OUTCOME

Introduction

According to the European Society of Cardiology guidelines secondary prevention ICD implantation is a class I indication only for those patients with an estimated survival > 1 year with a good functional status. However, it is not specified how to assess the functional status and its evaluation could be quite difficult in the case of out–of–hospital cardiac arrest (OHCA) survivors with major neurological outcomes. Cerebral Performance Category (CPC) is the most widespread scale to define the neurological and functional outcome of OHCA survivors, but it is not known if it can be used to guide ICD implantation.

Objective

To evaluate whether the presence of a bad neurological outcome (CPC > 2) at discharged could be used as a prognostic index in order to evaluate the implantation of an ICD in OHCA survivors. Materials and Methods. We considered all the patients who had a cardiac arrest from 01/10/2014 to 30/09/2019 presenting a CPC> 2 at discharge. The territory included was that of the Province of Pavia (550000 inhabitants) from 2014 to 2018 and of the Provinces of Pavia, Lodi, Cremona and Mantua (1550000 inhabitants) from 2019. We assessed the survival and the neurological status variation at 1–year.

Results

In the study period, CPR was attempted in 2998 confirmed OHCAs. 227 patients (7.6%) were discharged alive and in 218 of these, CPC was available. 51 patients (23.4%) had a CPC>2 at discharge (22 CPC = 3, 24 CPC = 4 and 5 CPC = A). 1–year follow–up was available in 200 patients: among 158 alive, 12 (7.6%) had CPC>2 (7 CPC = 3 and 5 CPC = 4). 1–year survival of patients with CPC>2 at discharge was significantly lower those discharged with CPC≤2 (39.6% vs 91.6% p < 0.001). Only 19/48 patients discharged with CPC>2 survived at 1 year: a good cerebral performance was recovered in 6 patients (31.6%), while CPC>2 persisted in 11 (58%) and the CPC value was unknown in 2 of them.

Conclusions

Our results highlight that 1–year survival is quite low in patients with CPC>2 at discharge and that an improvement in cerebral performance occurs only in a minority of them. This evidence suggests the need for clinical re–evaluation after the event in order to carefully evaluate whether to implant an ICD in this kind of patients.

C26 COMPLETE REVASCULARISATION IMPROVES SURVIVAL OF PATIENTS RESUSCITATED AFTER AN OUT–OF–HOSPITAL CARDIAC ARREST

Background

Sudden cardiac death is a major issue in industrialised countries and survival of patients after out–of–hospital cardiac arrest (OHCA) remains low. Acute myocardial infarction (AMI) is the principal cause of OHCA and myocardial revascularisation plays a positive role on survival. In this setting little is known about the role of complete (CR) versus culprit–only revascularisation (IR) on survival.

Purpose

The aim of this study was to assess whether CR could lead to a better one–year survival as compared to IR. Methods. Among patients prospectively enrolled in the Lombardia CARe OHCA registry from January 1 2015 to May 1 2021, who underwent a coronary angiography (CAG) at the Fondazione IRCCS Policlinico San Matteo were enrolled in this study. CAGs were retrospectively reviewed by two interventional cardiologists. Prehospital and survival data were retrieved from the registry.

Results

We enrolled 239 patients [mean age 63.7±12.4 years; male 79.9%; shockable presenting rhythm 84.1%; AMI at post ROSC ECG 67.9%; ejection fraction 37% (30–45), circulatory support with ECMO 10.9%]. Among the 119 (50%) patients with multi–vessel disease, 82 (69%) received IR whereas 37 (31%) received CR [8 during the first procedure, 29 in a second procedure with a median time after OHCA of 5 (2.5–10) days]. This latter group showed significantly higher one–year survival (54.9% vs 16.2%, p < 0.001). At univariable logistic regression only a shockable presenting rhythm and the presence of chronic total occlusion (CTO) were significantly associated with the probability of receiving a CR [OR 5.1 (95%CI 1.1–22), p = 0.03; OR 0.37 (95%CI 0.16–0.85), p = 0.02 respectively]. However, at multivariable regression analysis only CTO was significantly associated with the probability of receiving a CR [OR 0.36 (95%CI 0.15–0.9), p = 0.007]. At Cox multivariable regression model cardiac arrest duration (longer that the median value of 24 min) and CR were independently associated with the probability of death [HR 3.6 (95%CI 1.9–6.9), p < 0.001; HR 0.2 (95%CI 0.1–0.9), p = 0.02]. Similarly, cardiac arrest duration, CR and a shockable presenting rhythm were associated with the probability of death or poor neurologic outcome [HR 3.3 (95%CI 1.8–6), p < 0.001; HR 0.5 (95%CI 0.3–0.9), p = 0.03 and HR 0.2 (95%CI 0.1–0.5), p < 0.001].

Conclusions

Complete revascularisation is independently associated with a better one–year survival in patients resuscitated from an out–of–hospital cardiac arrest.

P30 CARDIAC ARRESTS IN SPORTS: WHAT IS DIFFERENT COMPARED TO OTHER PUBLIC PLACES?

Introduction

Cardiac arrests in sports can involve professional athletes, amateurs, but also spectators of sports competitions. Sports facilities are the only ones for which the current law provides for the presence of an automatic external defibrillator (AED) and trained personnel, unlike other public places (schools, work, street, station, general public buildings) where it is only recommended.

Objective

To compare patient characteristics, presentation rhythm, bystander cardiopulmonary resuscitation (CPR), AED use before emergency medical services (EMS) arrival, and return of spontaneous circulation (ROSC) longer than 30 seconds in the Utstein category of out–of–hospital cardiac arrests (OHCAs) in sports compared to events in other public places.

Materials and Methods

We considered all the OHCAs occurred from 01/01/2015 to 31/12/2020 in the provinces of Pavia, Lodi, Cremona, Mantua and Varese (2400000 inhabitants), excluding the OHCAs occurred at home, in long–term care facilities and witnessed by the EMS.

Results

During the study period, 22 OHCAs occurred in sports and 552 in other public places (school, work, street, station, public buildings). The age is similar in the two groups [sport 59 years (IQR 53.5–66.7) vs other 63 years (IQR 51–75), p = 0.2]. In sports, there is a trend in favor of shockable rhythms (13/22=59% vs 185/552=33%, p = 0.1). The percentage of CPR performed by bystanders in sports is significantly higher than in other public places (20/22=91% vs 299/552=54%, p = 0.003), as the bystander AED use (11/22=50% vs 64/552=12%, p < 0.001) and bystander AED shock (7/22=31% vs 27/552=5%, p < 0.001) before EMS arrival. A ROSC greater than 30 seconds was obtained in 59% of OHCAs in sports, with a statistically significant difference compared to events in other public places (13/22=59% vs 166/552=30%, p = 0.015).

Conclusions

During sports competitions there is a greater ability to intervene in case of cardiac arrest, which determines a higher probability of obtaining ROSC, although in terms of age or presentation rhythm the patients are comparable to OHCA victims in other places public. These results suggest the need for an AED and trained personnel in other public places as well.

Out-of-hospital cardiac arrest and ambient air pollution: a dose-effect relationship and a predictive role in OHCA risk

Background

Pollution has been suggested as a precipitating factor for cardiovascular diseases via a series of different mechanisms. However, data about the link between the different air pollutants and the risk of out-of-hospital cardiac arrest (OHCA) are limited and controversial.

Purpose

The primary aim of this study is to examine the impact of short-term exposure to particulate and gaseous pollutants on the incidence of OHCA in a vast metropolitan and rural area that encompasses four provinces of the Po Valley in Northern Italy, one of the most polluted areas in Italy and Europe due to its levels of industrialization and high population density. The secondary aim of this study is to look for a dose-effect curve, which could help predict OHCA incidence based on the concentration of pollutants in a specific area.

Methods

This is a retrospective analysis of prospectively collected data both in the OHCA registry (Lombardia CARe) and in the database of the regional agency for environmental protection (ARPA) of the Lombardy region. All medical OHCAs and the mean daily concentration of pollutants including fine particulate matter (PM10, PM2.5), benzene (C6H6), carbon monoxide (CO), nitrogen dioxide (NO2), sulphur dioxide (SO2) and ozone (O3) were considered from January 1st to December 31st, 2019 in the southern part of the Lombardy region (provinces of Pavia, Lodi, Cremona and Mantua; 7863 km2; about 155ehab724.2654 inhabitants). Days were divided into high or low incidence of OHCA according to the median daily incidence. A Probit dose-response analysis and both uni- and multivariable logistic regression models were provided for each pollutant.

Results

The median daily incidence of OHCA was 0.3 cases/100,000 inhabitants. Benzene was the pollutant with the greatest difference between days at high and low incidence of OHCA [0.7 (IQR 0.4–1.2) vs 0.4 (IQR 0.3–0.7), p<0.001], whereas SO2 had the lowest and least significant difference between the two periods [3.2 (IQR 2.8–3.6) vs 3.1 (IQR 2.7–3.5), p=0.046]. O3 showed a countertrend, being significantly higher in the low-incidence period [29.9 (IQR 10.9–61.7) vs 56.1 (IQR 25.5–74.1), p<0.001] as well as temperature [10.1— (IQR 5.2–14.8) vs 15.1 (IQR 8.9–23.3), p<0.001]. By using the Probit regression analysis and after adjusting for temperature, a dose-response relationship was demonstrated for all the tested pollutants.

Conclusions

Our results clarify the link between pollutants and the acute risk of cardiac arrest suggesting the need of both improving the air quality and integrating pollution data in future models.

Funding Acknowledgement

Type of funding sources: None.

Amiodarone and amplitude spectral area of ventricular fibrillation in patients with out-of-hospital cardiac arrest

Background

Ventricular fibrillation is the most common cause of out-of-hospital cardiac arrest (OHCA) and the use of antiarrhythmic drug therapy is usually recommended in addition to defibrillation. The role of the amplitude spectral area (AMSA) of ventricular fibrillation as a predictor of defibrillation efficacy has been established, while the existing data in favour of the use of amiodarone has been assessed with poor evidence and controversy.

Purpose

The aim of our study is to evaluate whether the administration of amiodarone during resuscitation could affect AMSA values.

Materials

All the OHCAs with a shockable presenting rhythm and attempted resuscitation which occurred from January 2015 to June 2019 in the province of Pavia were considered. Both the end-tidal CO2 (ETCO2) and AMSA values were calculated by retrospectively analyzing the data collected by the Corpuls 3 monitors/defibrillators (Corpuls, Kaufering, Germany) used in the territory and by considering a pre-shock interval of 2 seconds.

Results

Among a total of 3413 OHCAs, resuscitation was attempted in 2195 cases (64%), 377 (17%) had a shockable presenting rhythm and in 112 cases (3.4%) it was possible to obtain the values of ETCO2 and AMSA for a total of 391 shocks. Among these, 301 shocks (77%) were delivered to patients who received amiodarone during resuscitation. The success rate of each single shock was similar in the two groups but with an unfavorable trend for amiodarone (amiodarone 43.5% vs no amiodarone 54.4%, p=0.07). AMSA was significantly lower in patients treated with amiodarone (7.9 mV·Hz, IQR 5.4–12.2 vs 10.6 mV·Hz, IQR 7.1–14.1; p<0.001). According to a multivariate analysis, the administration of amiodarone and the time to shock were independent predictors of AMSA values. Lastly, on a sample of 124 shocks, homogeneous for age, sex, ETCO2, outcome of resuscitation and randomly matched, the AMSA of patients who received amiodarone was significantly lower (7.2 mV·Hz, IQR 7.2–11.7 vs 9.7 mV·Hz, IQR 6.7–12.5; p=0.02).

Conclusions

Our results indicate that amiodarone administration is associated with lower values of AMSA. Since higher AMSA values are known to be associated with a higher probability of shock rate success, this could help to better clarify the controversial role of amiodarone administration in patients with OHCA.

Funding Acknowledgement

Type of funding sources: None.