CPR Rhythms Thesis PPT

Prevalence and factors associated with initial and subsequent shockable cardiac arrest rhythms and their association with patient outcomes in dogs and cats undergoing cardiopulmonary resuscitation:a RECOVER registry study

Maria Laura Vega SuarezFinal Masters Exam Presentation Washington State University June 20th 2023

Introduction

13.7%SHKR

• Rhythm diagnosis informs advanced life support measures to follow during CPR1,2
• Cardiac arrest rhythms: shockable (SHKR) and non-shockable (NSHKR)1,2

• Both in-hospital and out-of-hospital arrest in people are characterized by a significantly higher prevalence of NSHKR3

+ info

+ info

78.3% NSHKR

info

+ info

Data from Get With The Guidelines 2020 based on 33,874 adult in-hospital cardiac arrests in 328 hospitals3

1. Fletcher et al. J Vet Emerg Crit Care. 2012 2. Panchal et al. Circulation. 2020 3. Tsao et al. Circulation. 2022

Introduction

• In people, type of initial arrest rhythm is strongly associated with patient outcome1
• Must consider factors associated with initial SHKR (I-SHKR) such as monitored or witnessed arrest, ischemic heart disease, dysrhythmias, and valvular heart disease2

Survival rates based on data from the Get With The Guidelines-Resuscitation registry on all adult in-hospital cardiac arrest from 2000 to 2017 1

1. Andersen et al. JAMA. 2019 2. Stankovic et al. Resuscitation. 2021

Introduction

• Reported prevalence of I-SHKR 8-21% in dogs and 0-16% in cats1-5
• Reported incidence of subsequent SHKR (S-SHKR) 7-22% in dogs and 7% in cats3-5
• Only one study has found an association between I-SHKR and return of spontaneous circulation, albeit only in dogs5
• Limited data in veterinary medicine, no description of factors associated with rhythm diagnosis, and no investigation on association between S-SHKR and outcome

4. Kawase et al. J Vet Med Sci. 2018 5. Hoehne et al. Front Vet Sci. 2019

1. Waldrop et al. J Vet Emerg Crit Care. 2004 2. Hofmeister et al. J Vet Emerg Crit Care. 2009 3. MacIntyre et al. J Vet Emerg Crit Care. 2014

Objectives

• Describe the prevalence of I-SHKR and I-NSHK and the incidence of S-SHKR
• Report associations of cardiac arrest rhythms with patient outcomes

• Explore factors associated with I-SHKR, I-NSHKR, and S-SHKR

Hypothesis

• I-SHKR will be less prevalent and will be associated with improved patient outcomes in comparison to I-NSHK
• Development of S-SHKR will be associated with worse patient outcomes

Materials & Methods

• Multi-institutional prospective case series 2016-2021, retrospectively analyzed
• Data obtained from the RECOVER CPR registry1

• Dogs and cats undergoing CPR with at least one cardiac arrest rhythm diagnosis and outcome information were included

• Exclusion criteria: no ECG or defibrillator, unknown first cardiac arrest rhythm, or patient outcome

Reassessment Campagin on Veterinary Resuscitation

1. Hoehne et al. J Vet Emerg Crit Care. 2022

Materials & Methods

Materials & Methods

AsystolePulseless electrical activity (PEA) Severe bradycardia <30-40bpm (Brady) NSHKR

• Cardiac arrest rhythm classification as NSHKR or SHKR1

• First recorded rhythm considered initial rhythm (I-NSHK vs I-SHKR)
• I-NSHKR followed by SHKR considered subsequent SHKR (S-SHKR)

SHKRPulseless ventricular tachycardia (PVT)Ventricular fibrillation (VF)

1. Boller et al. J Vet Emerg Crit Care. 2016

Materials & Methods

In accordance with Utstein-style CPR reporting guidelines; variables regarding animal, arrest, hospital, and outcome1

Animal variables

• Species, sex, age

• Body weight
• Chest conformation (dogs)
• Disease category at admission & comorbidites

• ALS measures in place at time of arrest
• Anesthesia or sedation

• Suspected cause
• Ventilation route
• Drugs administered
• EtCO2
• Open chest

Arrest variables

• Witnessed
• CPR duration
• Time CPA to CPR
• Time of day

• Location

1. Boller et al. J Vet Emerg Crit Care. 2016

https://recoverinitiative.org/recover-cpr-record-sheet-revamped/

Materials & Methods

Hospital variables1

• Electronic survey completed annually
• Type of practice:
• 8 private, 8 academic institutions
• 75% emergency and critical care centers
• Location: North America, Europe, & Australia

• Access to ECG, defibrillator, and CPR drugs

Outcomes2

• Any return of spontaneous circulation (ROSC)
• Sustained ROSC (>20min)
• Survival to hospital discharge (STHD)

1. Hoehne et al. J Vet Emerg Crit Care. 2022

2. Boller et al. J Vet Emerg Crit Care. 2016

Statistical analysis

• Power analysis based on previous veterinary literature1
• Summary statistics: hospital, animal, arrest, and outcome variables
• Binary and categorical data: proportions and 95% CI
• Continuous variables: Shapiro-Wilk test; mean +/- SDfor normally distributed variables; median (range) for non-normally distributed data

1. Hoehne et al. Front Vet Sci. 2019

Statistical analysis

• Univariate binary logistic regression analyses to compare animals with/without I-SHKR and those that did/did not develop S-SHKR that achieved ROSC to those that did not

• Multiple multivariate logistic regression models with I-SHKR and S-SHKR as the dependent outcomes of interest to evaluate factors associated with those rhythms

• Variables with a P-value of < 0.05 and those previously shown to be associated with cardiac arrest rhythm diagnosis1-5 were included in multivariable backwards logistic regression model

• Odds ratios and 95% CI were computed and P-values < 0.05 considered statistically significant

• Model fit was assessed using the Hosmer-Lemeshow goodness of fit test

4. Lin et al. Mayo Clin Proc. 2017 5. Rajan et al. Resuscitation. 2017

1. Meaney et al. Crit Care Med. 2010 2. Stankovic et al. Resuscitation. 2021 3. Granfeldt et al. Resuscitation. 2016

Results

Included cases

Unknown rhythmn= 145

Total casesn= 772

Included casesn= 627

Results

Suspected causes of arrest

Results

Initial cardiac arrest rhtyhm prevalence

Cats

Dogs

+ info

+ info

info

+ info

• I-SHKR 4% (n=20)
• S-SHKR 15% (n=66)

• I-SHKR 5% (n=8)
• S-SHKR 5% (n=8)

Results

• Information on whether animals were defibrillated was available for 25/28 (89%) and 74 (100%) of animals with I-SHKR and S-SHKR, respectively

• Details of defibrillation dose and number of defibrillation attempts are not collected in the CPR registry

Results

Factors associated with I-SHKR in dogs and cats

• Higher odds of I-SHKR: metabolic cause of arrest, lidocaine administration, amiodarone administration
• Lower odds of I-SHKR: daytime arrest (7am-7pm), location ICU, location ER, out-of-hospital arrest, epinephrine administration

Results

Factors associated with S-SHKR in dogs and cats

• Higher odds of S-SHKR: increasing body weight, hemorrhage or intracranial cause of arrest, lidocaine administration
• Lower odds of S-SHKR: location ICU, location ER, out-of-hospital arrest, epinephrine administration

Results

Overall outcomes

+ info

+ info

info

+ info

Dogs

Cats

Results

Outcomes by cardiac arrest rhythm

No significant difference in ROSC between I-SHKR and I-NSHKR, nor between those that developed S-SHKR and those that did not

Discussion

• First multicenter veterinary study to describe the prevalence, factors associated with, and prognostic implication of cardiac arrest rhythms in dogs and cats undergoing CPR

• I-SHKR prevalence was lower than in people1 and than reported in veterinary literature2-6
• Higher prevalence of cardiac etiologies in CPA in people (50-60%)7
• Higher prevalence of heart failure in other veterinary studies3,4

• ROSC and STHD rates were lower than in previous veterinary studies2-5,8,9
• More out-of-hospital arrests and fewer witnessed and peri-anesthetic arrests10

8. Fletcher et al. J Vet Emerg Crit Care. 2012 9. Kass and Haskins. J Vet Emerg Crit Care. 1992 10. Hoehne et al. Front Vet Sci. 2019

1. Tsao et al. JAMA. 2019 2. Hofmeister et al. J Vet Emerg Crit Care. 2009 3. MacIntyre et al. J Vet Emerg Crit Care. 2014 4. Kawase et al. J Vet Med Sci. 2018

5. Hoehne et al. Front Vet Sci. 2019 6 Waldrop et al. J Vet Emerg Crit Care. 2004 7. Andersen et al. JAMA. 2019

Discussion

• No difference in ROSC between I-SHKR and I-NHSKR
• Underpowered due to low prevalence of I-SHKR
• Fewer animals received defibrillation and median time to defibrillation was longer than previous study reporting higher ROSC with I-SHKR1
• Euthanasia bias and low STHD rates hindered assessment of other improved outcome measures relevant in people2

• No difference in ROSC between I-NSHKR that then developed S-SHKR and those that did not
• Association between S-SHKR and outcomes in people is variable3-7

1. Hoehne et al. Front Vet Sci. 2019 2. Stankovic et al. Resuscitation. 2021 3. Meaney et al. Crit Care Med. 2010

6. Zhang et al. Cardiol Res Pract. 2020 7. Weisfeldt and Becker. JAMA. 2002

4. Thomas et al. Resuscitation. 2013 5. Zheng et al. Resuscitation. 2016

Discussion

• Metabolic/electrolyte disturbances and I-SHKR: dyscalcemia, dyskalemia, dysmagnesemia, and acidosis can influence ionic current kinetics and have known arrhythmogenic potential1-4

• Hemorrhage and S-SHKR: sympathetic activation leads to release of cardiac norepineprhine and neuropeptide Y which have arrythmogenic properties and lower the VF threshold5,6
• Intracranial/brain disease and S-SHKR: brainstem compression7 or altered autonomic system homeostasis8

4. Yano et al. Int. J. Angiol. 1996 5. Nguyen and Vaseghi. J Atr Fibrillation. 2020 6. Cauti et al. Eur Heart J. 2021

7. Stober et al.. Stroke. 1988 8. Shen and Zipes. Circ Res. 2014

1. El-Sherif and Turitto. Cardiol J. 20112. Hohnloser et al. Am Heart J. 19863. Orchard and Cingolani. Cardiovasc Res. 1994

Discussion

• Administration of lidocaine and amiodarone and I-SHKR/S-SHKR and administration of epinephrine and lower odds for I-SHKR/S-SHKR
• Likely represent compliance with RECOVER CPR guidelines, but timeline remains unknown

• Findings do not support concers from previously described proarrhythmogenic properties1-5, albeit safety cannot be afirmed

• Lack of defibrillation capabilities is frequent in general practice6-10 and likely carries limited negative impact to patient outcomes given study findings

8. Kruppert et al. Schweiz Arch Tierheilkd. 2020 9. Hagley et al. Front Vet Sci.. 2022 10. Boller et al. J Vet Emerg Crit Care. 2010

5. Sosunov et al. Cardiovasc Res. 2004 6. Hoehne et al. Front Vet Sci. 2019 7. Gillespie et al. Front Vet Sci. 2019

1. Hoppe et al. Circulation. 1998 2. Koumi et al. J Clin Invest. 1995 3. Bassiakou et al. Eur J Pharmacol. 2009 4. Holmberg et al. Resuscitation. 2019

Limitations

• Possible type II error due to low prevalence/incidence of shockable rhythms
• Possible sampling bias
• Data from cardiac arrest rhythms and in-hospital vs out-of-hospital arrests were not analyzed separately
• Retrospective nature and limited information gathetered from the CPR forms

Conclusions

• Initial and subsequent shockable cardiac arrest rhytms are infrequently encountered in dogs and cats, and no association with ROSC rates was detected

• Recognizing factors associated with SHKR could help optimize preparedness and interventions: in animals with suspected hemorrhage, intracranial disease, or a metabolic cause of arrest, insitute ECG monitoring promptly as they have higher odds of having I-SHKR or S-SHKR

• Future studies to include larger population and stratify outcomes by specific cardiac arrest rhythm

Acknowledgements

Exam committee: Drs. Linda Martin, Sabrina Hoehne, and Lais MalavasiManuscript co-authors: Drs. Steven Epstein, Elizabeth Davidow, Linda Martin, and Sabrina Hoehne RECOVER CPR Registry committee and contributing hospitals

THANK YOU

References

• Fletcher DJ, Boller M, Brainard BM, et al. Recover evidence and knowledge gap analysis on veterinary CPR. part 7: Clinical guidelines. J Vet Emerg Crit Care. 2012;22(1):102-131.
• Panchal AR, Bartos JA, Cabañas JG, et al. Adult Basic and Advanced Life Support Writing Group. Part 3: Adult Basic and Advanced Life Support: 2020 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care. Circulation. 2020;16(2):366-468.
• Tsao CW, Aday AW, Almarzooq ZI, et al. Heart Disease and Stroke Statistics-2022 Update: A Report From the American Heart Association. Circulation. 2022;145(8):153-639.
• Andersen LW, Holmberg MJ, Berg KM, et al. In-Hospital Cardiac Arrest: A Review. JAMA. 2019;321(12):1200-1210.
• Nolan JP, Soar J, Smith GB, et al. Incidence and outcome of in-hospital cardiac arrest in the United Kingdom National Cardiac Arrest Audit. Resuscitation. 2014;85(8):987-992.
• Chan PS, McNally B, Tang F, et al. Recent trends in survival from out-of-hospital cardiac arrest in the United States. Circulation. 2014;130(21):1876-1882.
• Meaney PA, Nadkarni VM, Kern KB, et al. Rhythms and outcomes of adult in-hospital cardiac arrest. Crit Care Med. 2010;38(1):101-108.
• Thomas AJ, Newgard CD, Fu R, et al. Survival in out-of-hospital cardiac arrests with initial asystole or pulseless electrical activity and subsequent shockable rhythms. Resuscitation. 2013;84(9):1261-1266.
• Luo S, Zhang Y, Zhang W, et al. Prognostic significance of spontaneous shockable rhythm conversion in adult out-of-hospital cardiac arrest patients with initial non-shockable heart rhythms: a systematic review and meta-analysis. Resuscitation. 2017;121:1-8.
• Stankovic N, Høybye M, Holmberg MJ, et al. Factors associated with shockable versus non-shockable rhythms in patients with in-hospital cardiac arrest. Resuscitation. 2021;158:166-174.
• Emoto R, Nishikimi M, Shoaib M, et al. Prediction of Prehospital Change of the Cardiac Rhythm From Nonshockable to Shockable in Out-of-Hospital Patients With Cardiac Arrest: A Post Hoc Analysis of a Nationwide, Multicenter, Prospective Registry. J Am Heart Assoc. 2022;11(12):e025048.
• Waldrop JE, Rozanski EA, Swanke ED, et al. Causes of cardiopulmonary arrest, resuscitation management, and functional outcome in dogs and cats surviving cardiopulmonary arrest. J Vet Emerg Crit Care. 2004;14:22–29.
• Hofmeister EH, Brainard BM, Egger CM, Kang S. Prognostic indicators for dogs and cats with cardiopulmonary arrest treated by cardiopulmonary cerebral resuscitation at a university teaching hospital. J Vet Emerg Crit Care 2009;235(1):50–57.
• McIntyre RL, Hopper K, Epstein SE. Assessment of cardiopulmonary resuscitation in 121 dogs and 30 cats at a university teaching hospital (2009-2012). J Vet Emerg Crit Care. 2014;24(6):693-704.
• Kawase K, Ujiie H, Takaki M, Yamashita K. Clinical outcome of canine cardiopulmonary resuscitation following the RECOVER clinical guidelines at a Japanese nighttime animal hospital. J Vet Med Sci. 2018;80(3):518-525.

References

• Hoehne SN, Hopper K, Epstein SE. Prospective Evaluation of Cardiopulmonary Resuscitation Performed in Dogs and Cats According to the RECOVER Guidelines. Part 2: Patient Outcomes and CPR Practice Since Guideline Implementation. Front Vet Sci. 2019;6:439.
• Hoehne SN, Balakrishnan A, Silverstein DC, et al. Reassessment campaign on Veterinary Resuscitation (RECOVER) Initiative small animal CPR Registry Report 2016–2021. J Vet Emerg Crit Care. 2022 Dec 27. Online ahead of print.
• Harris PA, Taylor R, Thielke R, et al. Research Electronic Data Capture (REDCap) - A metadata-driven methodology and workflow process for providing translational research informatics support. J Biomed Inform. 2009;42(2):377–381.
• Boller M, Fletcher DJ, Brainard BM, et al. Utstein-style guidelines on uniform reporting of in-hospital cardiopulmonary resuscitation in dogs and cats. A RECOVER statement. J Vet Emerg Crit Care. 2016;26(1):11–34.
• Granfeldt A, Wissenberg M, Hansen SM, et al. Clinical predictors of shockable versus non-shockable rhythms in patients with out-of-hospital cardiac arrest. Resuscitation. 2016;108:40–47.
• Lin YN, Chang SS, Wang LM, et al. Prehospital Predictors of Initial Shockable Rhythm in Out-of-Hospital Cardiac Arrest: Findings From the Taichung Sudden Unexpected Death Registry (THUNDER). Mayo Clin Proc. 2017;92(3):347–59.
• Rajan S, Folke F, Hansen SM, et al. Incidence and survival outcome according to heart rhythm during resuscitation attempt in out-of-hospital cardiac arrest patients with presumed cardiac etiology. Resuscitation. 2017;114:157–163.
• Kass, PH, Haskins, SC. Survival Following Cardiopulmonary Resuscitation in Dogs and Cats. J Vet Emerg Crit Care. 1992;2(2):157-165.
• Hoehne SN, Epstein SE, Hopper K. Prospective Evaluation of Cardiopulmonary Resuscitation Performed in Dogs and Cats According to the RECOVER Guidelines. Part 1: Prognostic Factors According to Utstein-Style Reporting. Front Vet Sci. 2019;6: 384.
• Gillespie Í, Fletcher DJ, Stevenson MA, Boller M. The Compliance of Current Small Animal CPR Practice With RECOVER Guidelines: An Internet-Based Survey. Front Vet Sci. 2019;6: 181.
• Kruppert A, Adamik K, Hoehne SN. The clinical practice of small animal CPR and compliance with RECOVER guidelines in Switzerland: an internet-based survey. Schweiz Arch Tierheilkd. 2020;162(12):755-770.
• Hagley SP, Kruppert A, Leal RO, et al. Self-Reported Clinical Practice of Small Animal Cardiopulmonary Resuscitation and Compliance With RECOVER Guidelines Among Veterinarians in Eight Western European Regions. Front Vet Sci. 2022;9:919206.
• Chugh SS, Reinier K, Teodorescu C, et al. Epidemiology of sudden cardiac death: clinical and research implications. Prog Cardiovasc Dis. 2008;51(3):213-28.
• Cobb LA, Fahrenbruch CE, Olsufka M, Copass MK. Changing incidence of out-of-hospital ventricular fibrillation, 1980-2000. JAMA. 2002;288(23):3008-3013.

References

• Keller SP, Halperin HR. Cardiac arrest: the changing incidence of ventricular fibrillation. Curr Treat Options Cardiovasc Med. 2015;17(7):392.
• Dazio VER, Gay JM, Hoehne SN. Cardiopulmonary resuscitation outcomes of dogs and cats at a veterinary teaching hospital before and after publication of the RECOVER guidelines. JSAP 2022 Dec 23. Online ahead of print.
• Tran A, Fernando SM, Rochwerg B, et al. Pre-arrest and intra-arrest prognostic factors associated with survival after in-hospital cardiac arrest: systematic review and meta-analysis. Resuscitation. 2020;153:119-135.
• Valenzuela TD, Roe DJ, Nichol G, et al. Outcomes of rapid defibrillation by security officers after cardiac arrest in casinos. N Engl J Med. 2000;343(17):1206-1209.
• Chan PS, Krumholz HM, Nichol G, et al. Delayed time to defibrillation after in-hospital cardiac arrest. N Engl J Med. 2008;358(1):9-17.
• Goto Y, Maeda T, Nakatsu-Goto Y. Prognostic implications of conversion from nonshockable to shockable rhythms in out-of-hospital cardiac arrest. Crit Care. 2014;18(5):528.
• Kitamura, N., Nakada, Ta., Shinozaki, K. et al. Subsequent shock deliveries are associated with increased favorable neurological outcomes in cardiac arrest patients who had initially non-shockable rhythms. Crit Care. 2015;19(1):322.
• Iversen BN, Meilandt C, Væggemose U, et al. Pre-charging the defibrillator before rhythm analysis reduces hands-off time in patients with out-of-hospital cardiac arrest with shockable rhythm. Resuscitation. 2021;169:23-30.
• Hallstrom A, Rea TD, Mosesso VN Jr, et al. The relationship between shocks and survival in out-of-hospital cardiac arrest patients initially found in PEA or asystole. Resuscitation. 2007;74(3):418-426.
• Herlitz J, Svensson L, Engdahl J, Silfverstolpe J. Characteristics and outcome in out-of-hospital cardiac arrest when patients are found in a non-shockable rhythm. Resuscitation. 2008;76(1):31-36.
• Olasveengen TM, Samdal M, Steen PA, et al. Progressing from initial non-shockable rhythms to a shockable rhythm is associated with improved outcome after out-of-hospital cardiac arrest. Resuscitation. 2009;80(1):24-29.
• Han KS, Lee SW, Lee EJ, Kim SJ. Prognostic Value of the Conversion to a Shockable Rhythm in Out-of-Hospital Cardiac Arrest Patients with Initial Non-Shockable Rhythm. J Clin Med. 2019;8(5):1-12.
• Han KS, Lee SW, Lee EJ, et al. Association between shockable rhythm conversion and outcomes in patients with out-of-hospital cardiac arrest and initial non-shockable rhythm, according to the cause of cardiac arrest. Resuscitation. 2019;142:144-152.
• Wah W, Wai KL, Pek PP, et al. Conversion to shockable rhythms during resuscitation and survival for out-of hospital cardiac arrest. Am J Emerg Med. 2017;35(2):206-213.
• Zheng R, Luo S, Liao J, et al. Conversion to shockable rhythms is associated with better outcomes in out-of-hospital cardiac arrest patients with initial asystole but not in those with pulseless electrical activity. Resuscitation. 2016;107:88-93.

References

• Zhang W, Luo S, Yang D, et al. Conversion from Nonshockable to Shockable Rhythms and Out-of-Hospital Cardiac Arrest Outcomes by Initial Heart Rhythm and Rhythm Conversion Time. Cardiol Res Pract. 2020;2020:1-8.
• Weisfeldt ML, Becker LB. Resuscitation after cardiac arrest: a 3-phase time-sensitive model. JAMA. 2002;288(23):3035-3038.
• Hallstrom A, Herlitz J, Kajino K, Olasveengen TM. Treatment of asystole and PEA. Resuscitation. 2009;80(9):975-976.
• Boller, M, Fletcher, DJ. Update on Cardiopulmonary Resuscitation in Small Animals. Vet Clin North Am Small Anim Pract. 2020;50(6):1183-1202.
• Boller, M, Kellett‐Gregory, L, Shofer, FS, Rishniw, M. The clinical practice of CPCR in small animals: an internet-based survey. J Vet Emerg Crit Care. 2010;20(6):558–570.
• El-Sherif N, Turitto G. Electrolyte disorders and arrhythmogenesis. Cardiol J. 2011;18(3):233-245.
• Hohnloser SH, Verrier RL, Lown B, Raeder EA. Effect of hypokalemia on susceptibility to ventricular fibrillation in the normal and ischemic canine heart. Am Heart J. 1986;112(1):32-35.
• Orchard CH, Cingolani HE. Acidosis and arrhythmias in cardiac muscle. Cardiovasc Res. 1994;28(9):1312-1319.
• Yano K, Kapuku GK, Hirata T, et al. Effects of hypokalemia and disopyramide on electrical induction of ventricular tachyarrhythmia in nonischemic heart. Int. J. Angiol. 1996;5:105–109.
• Hopper K, Epstein SE, Kass PH, Mellema MS. Evaluation of acid-base disorders in dogs and cats presenting to an emergency room. Part 2: comparison of anion gap, strong ion gap, and semiquantitative analysis. J Vet Emerg Crit Care. 2014;24(5):502-508.
• Hoehne SN, Hopper K, Epstein SE. Association of point‐of‐care blood variables obtained from dogs and cats during cardiopulmonary resuscitation and following return of spontaneous circulation with patient outcomes. J Vet Emerg Crit Care 2022 Dec 27. Online ahead of print.
• Kuo K, Palmer L. Pathophysiology of hemorrhagic shock. J Vet Emerg Crit Care. 2022;32(1):22-31.
• Nguyen H, Vaseghi M. Sympathetic Denervation for Treatment of Ventricular Arrhythmias. J Atr Fibrillation. 2020;13(1):50-57.
• Cauti FM, Rossi P, Sommer P. The sympathetic nervous system and ventricular arrhythmias: an inseparable union. Eur Heart J. 2021;42(36):3588-3590.
• Stober T, Sen S, Anstätt T, Bette L. Correlation of cardiac arrhythmias with brainstem compression in patients with intracerebral hemorrhage. Stroke. 1988;19(6):688-692.
• Shen MJ, Zipes DP. Role of the autonomic nervous system in modulating cardiac arrhythmias. Circ Res. 2014;114(6):1004-1021.

References

• Hoppe UC, Jansen E, Südkamp M, Beuckelmann DJ. Hyperpolarization-activated inward current in ventricular myocytes from normal and failing human hearts. Circulation. 1998;97(1):55-65.
• Koumi S, Backer CL, Arentzen CE, Sato R. Beta-Adrenergic modulation of the inwardly rectifying potassium channel in isolated human ventricular myocytes. Alteration in channel response to beta-adrenergic stimulation in failing human hearts. J Clin Invest 1995;96(6):2870-2881.
• Bassiakou E, Xanthos T, Papadimitriou L. The potential beneficial effects of beta adrenergic blockade in the treatment of ventricular fibrillation. Eur J Pharmacol. 2009;616(1-3):1-6.
• Holmberg MJ, Issa MS, Moskowitz A, et al. Vasopressors during adult cardiac arrest: A systematic review and meta-analysis. Resuscitation. 2019;139:106-121.
• Koscik C, Pinawin A, McGovern H, et al. Rapid epinephrine administration improves early outcomes in out-of-hospital cardiac arrest. Resuscitation. 2013;84(7):915-920.
• Evans E, Swanson MB, Mohr N, et al. Epinephrine before defibrillation in patients with shockable in-hospital cardiac arrest: propensity matched analysis. BMJ. 2021;375:e066534.
• Sosunov EA, Obreztchikova MN, Anyukhovsky EP, et al. Mechanisms of alpha-adrenergic potentiation of ventricular arrhythmias in dogs with inherited arrhythmic sudden death. Cardiovasc Res. 2004;61(4):715-723.
• Witte K, Parsa-Parsi R, Vobig M, Lemmer B. Mechanisms of the circadian regulation of beta-adrenoceptor density and adenylyl cyclase activity in cardiac tissue from normotensive and spontaneously hypertensive rats. J Mol Cell Cardiol. 1995;27(5):1195-1202.
• Matsunaga T, Harada T, Mitsui T, et al. Spectral analysis of circadian rhythms in heart rate variability of dogs. Am J Vet Res. 2001;62(1):37-42.
• Arntz HR, Willich SN, Schreiber C, et al. Diurnal, weekly and seasonal variation of sudden death. Population-based analysis of 24,061 consecutive cases. Eur Heart J. 2000;21(4):315-320.
• Tripathi A, Girotra S, Toft LEB; American Heart Association's Get With the Guidelines-Resuscitation Investigators. Circadian variation of in-hospital cardiac arrest. Resuscitation. 2020;156:19-26.
• Neumar RW, Brown CG, Robitaille PM, Altschuld RA. Myocardial high energy phosphate metabolism during ventricular fibrillation with total circulatory arrest. Resuscitation. 1990;19(3):199-226.
• Kuschner CE, Becker LB. Recent advances in personalizing cardiac arrest resuscitation. Resuscitation 2019;8: F1000 Faculty Rev-915.
• Noszczyk-Nowak A, Michałek M, Kałuża E, et al. Prevalence of Arrhythmias in Dogs Examined between 2008 and 2014. J Vet Res 2017;61(1): 103-110.
• Nadkarni VM, Larkin GL, Peberdy MA, et al. First documented rhythm and clinical outcome from in-hospital cardiac arrest among children and adults. JAMA. 2006;295(1):50-57.
• Walsh CK, Krongrad E. Terminal cardiac electrical activity in pediatric patients. Am J Cardiol. 1983;51(3):557-561.
• Part 9: Pediatric basic life support. Resuscitation 2000;46(1-3):301-341.

Appendix

Table 1. Animal variables of 627 dogs and cats with initial shockable cardiac arrest rhythm (I-SHKR), initial non-shockable cardiac arrest rhythm (I-NSHKR), and those developing subsequent shockable rhythms (S-SHKR) during cardiopulmonary resuscitation.

Table 2. Arrest variables of 627 dogs and cats with initial shockable cardiac arrest rhythm (I-SHKR), initial non-shockable cardiac arrest rhythm (I-NSHKR), and those developing subsequent shockable rhythms (S-SHKR) during cardiopulmonary resuscitation.

Table 3. Initial cardiac arrest rhythm diagnosis prevalence in 627 dogs and cats undergoing cardiopulmonary resuscitation.

Table 4. Factors associated with an initial shockable cardiac arrest rhythm in dogs and cats suffering cardiopulmonary arrest and undergoing cardiopulmonary resuscitation as determined by multivariable logistic regression analysis.

Table 5. Factors associated with conversion from an initial non-shockable cardiac arrest rhythm to a subsequent shockable cardiac arrest rhythm in dogs and cats suffering cardiopulmonary arrest and undergoing cardiopulmonary resuscitation as determined by multivariable logistic regression analysis.

Figure 1. Summary of overall outcomes of patients suffering cardiopulmonary arrest (CPA) and undergoing cardiopulmonary resuscitation (CPR) and outcomes of patients with an initial shockable (I-SHKR), initial non-shockable (I-NSHKR), and subsequent shockable (S-SHKR) cardiac arrest rhythm. Data are presented as absolute numbers (percentages, 95% confidence interval).