Outcome of Apparently Unexplained Cardiac Arrest: Results From Investigation and Follow-Up of the Prospective Cardiac Arrest Survivors With Preserved Ejection Fraction Registry

Adam R M Herman; Christopher Cheung; Brenda Gerull; Christopher S Simpson; David H Birnie; George J Klein; Jean Champagne; Jeffrey S Healey; Karen Gibbs; Mario Talajic; Martin Gardner; Matthew T Bennett; Christian Steinberg; Mikyla Janzen; Michael H Gollob; Paul Angaran; Raymond Yee; Richard Leather; Santabhanu Chakrabarti; Shubhayan Sanatani; Vijay S Chauhan; Andrew D Krahn

doi:10.1161/CIRCEP.115.003619

Outcome of Apparently Unexplained Cardiac Arrest: Results From Investigation and Follow-Up of the Prospective Cardiac Arrest Survivors With Preserved Ejection Fraction Registry

Circ Arrhythm Electrophysiol. 2016 Jan;9(1):e003619. doi: 10.1161/CIRCEP.115.003619.

Authors

Adam R M Herman¹, Christopher Cheung¹, Brenda Gerull¹, Christopher S Simpson¹, David H Birnie¹, George J Klein¹, Jean Champagne¹, Jeffrey S Healey¹, Karen Gibbs¹, Mario Talajic¹, Martin Gardner¹, Matthew T Bennett¹, Christian Steinberg¹, Mikyla Janzen¹, Michael H Gollob¹, Paul Angaran¹, Raymond Yee¹, Richard Leather¹, Santabhanu Chakrabarti¹, Shubhayan Sanatani¹, Vijay S Chauhan¹, Andrew D Krahn²

Affiliations

¹ From the Division of Cardiology, Department of Medicine, University of British Columbia, Vancouver, BC, Canada (A.R.M.H., C.C., K.G., M.T.B., C.S., M.J., S.C., A.D.K.); Department of Cardiovascular Sciences, Libin Cardiovascular Institute, University of Calgary, Calgary, AB, Canada (B.G.); Division of Cardiology, Department of Medicine, Queen's University, Kingston, ON, Canada (C.S.S.); University of Ottawa Heart Institute, Ottawa, ON, Canada (D.H.B.); Division of Cardiology, Department of Medicine, Western University, London, ON, Canada (G.J.K., R.Y.); Department of Medicine, Quebec Heart and Lung Institute, Quebec City, QC, Canada (J.C.); Division of Cardiology, Department of Medicine, Population Health Research Institute, Hamilton, ON, Canada (J.S.H.); Department of Medicine, Montreal Heart Institute, Université de Montréal, Montreal, QC, Canada (M.T.); Division of Cardiology, Department of Medicine, QEII Health Sciences Center, Halifax, NS, Canada (M.G.); Division of Cardiology, Department of Medicine, University Health Network, Toronto, ON, Canada (M.H.G., V.S.C.); Division of Cardiology, Department of Medicine, St. Michael's Hospital, University of Toronto, Toronto, ON, Canada (P.A.); Division of Cardiology, Department of Medicine, Royal Jubilee Hospital, Victoria, BC, Canada (R.L.); and Division of Cardiology, Department of Pediatrics, BC Children's Hospital, Vancouver, BC, Canada (S.S.).
² From the Division of Cardiology, Department of Medicine, University of British Columbia, Vancouver, BC, Canada (A.R.M.H., C.C., K.G., M.T.B., C.S., M.J., S.C., A.D.K.); Department of Cardiovascular Sciences, Libin Cardiovascular Institute, University of Calgary, Calgary, AB, Canada (B.G.); Division of Cardiology, Department of Medicine, Queen's University, Kingston, ON, Canada (C.S.S.); University of Ottawa Heart Institute, Ottawa, ON, Canada (D.H.B.); Division of Cardiology, Department of Medicine, Western University, London, ON, Canada (G.J.K., R.Y.); Department of Medicine, Quebec Heart and Lung Institute, Quebec City, QC, Canada (J.C.); Division of Cardiology, Department of Medicine, Population Health Research Institute, Hamilton, ON, Canada (J.S.H.); Department of Medicine, Montreal Heart Institute, Université de Montréal, Montreal, QC, Canada (M.T.); Division of Cardiology, Department of Medicine, QEII Health Sciences Center, Halifax, NS, Canada (M.G.); Division of Cardiology, Department of Medicine, University Health Network, Toronto, ON, Canada (M.H.G., V.S.C.); Division of Cardiology, Department of Medicine, St. Michael's Hospital, University of Toronto, Toronto, ON, Canada (P.A.); Division of Cardiology, Department of Medicine, Royal Jubilee Hospital, Victoria, BC, Canada (R.L.); and Division of Cardiology, Department of Pediatrics, BC Children's Hospital, Vancouver, BC, Canada (S.S.). akrahn@mail.ubc.ca.

PMID: 26783233
DOI: 10.1161/CIRCEP.115.003619

Abstract

Background: The Cardiac Arrest Survivors with Preserved Ejection Fraction Registry (CASPER) enrolls patients with apparently unexplained cardiac arrest and no evident cardiac disease to identify the pathogenesis of cardiac arrest through systematic clinical testing. Exercise testing, drug provocation, advanced cardiac imaging, and genetic testing may be useful when a cause is not apparent.

Methods and results: The first 200 survivors of unexplained cardiac arrest from 14 centers across Canada were evaluated to determine the results of investigation and follow-up (age, 48.6±14.7 years, 41% female). Patients were free of evidence of coronary artery disease, left ventricular dysfunction, or evident repolarization syndromes. Advanced testing determined a diagnosis in 34% of patients at baseline, with a diagnosis emerging during follow-up in 7% of patients. Of those who were diagnosed, 28 (35%) had an underlying structural condition and 53 (65%) had a primary electric disease. During a mean follow-up of 3.15±2.34 years, 23% of patients had either a shock or an appropriate antitachycardia pacing from their implantable cardioverter defibrillator, or both. The implantable cardioverter defibrillator appropriate intervention rate was 8.4% at 1 year and 18.1% at 3 years, with no clear difference between diagnosed and undiagnosed subjects, or between those diagnosed with a primary electric versus structural pathogenesis.

Conclusions: Obtaining a diagnosis in previously unexplained cardiac arrest patients requires systematic clinical testing and regular follow-up to unmask the cause. Nearly half of apparently unexplained cardiac arrest patients ultimately received a diagnosis, allowing for improved treatment and family screening. A substantial proportion of patients received appropriate implantable cardioverter defibrillator therapy during medium-term follow-up.

Clinical trial registration: URL: http://www.clinicaltrials.gov. Unique identifier: NCT00292032.

Keywords: cardiac arrest; diagnosis; electrocardiography; genetic testing; survivors.

Publication types

Multicenter Study
Randomized Controlled Trial
Research Support, Non-U.S. Gov't

MeSH terms

Adolescent
Adult
Aged
Aged, 80 and over
Canada / epidemiology
Defibrillators, Implantable*
Diagnosis, Differential
Electrocardiography*
Female
Follow-Up Studies
Heart Arrest / diagnosis*
Heart Arrest / mortality
Heart Arrest / therapy
Humans
Male
Middle Aged
Registries*
Retrospective Studies
Stroke Volume / physiology*
Survival Rate / trends
Time Factors
Young Adult

Associated data

ClinicalTrials.gov/NCT00292032