Systematic Reviews
Copyright ©The Author(s) 2019. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Cardiol. Mar 26, 2019; 11(3): 103-119
Published online Mar 26, 2019. doi: 10.4330/wjc.v11.i3.103
Risk factors for sudden cardiac death to determine high risk patients in specific patient populations that may benefit from a wearable defibrillator
Hilal Mohammed Khan, Stephen J Leslie
Hilal Mohammed Khan, Stephen J Leslie, Cardiac Unit, Raigmore Hospital, Inverness IV2 3UJ, United Kingdom
Stephen J Leslie, Department of Diabetes and Cardiovascular Science, University of the Highlands and Islands, The Centre for Health Science, Old Perth Road, Inverness IV2 3JH, United Kingdom
Author contributions: Khan HM and Leslie SJ contributed equally to this work; designed research; performed research; and wrote the paper.
Conflict-of-interest statement: The authors have no conflicts of interest to declare in relation to this manuscript.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Corresponding author: Stephen J Leslie, FRCP (C), MBBS, MRCP, PhD, Professor, Cardiac Unit, Raigmore Hospital, Inverness IV2 3UJ, United Kingdom. stephen.leslie@nhs.net
Telephone: +44-1463-705459
Received: January 6, 2019
Peer-review started: January 8, 2019
First decision: January 21, 2019
Revised: January 27, 2019
Accepted: March 16, 2019
Article in press: March 16, 2019
Published online: March 26, 2019
Processing time: 94 Days and 7.3 Hours
Abstract
BACKGROUND

There is a high risk for sudden cardiac death (SCD) in certain patient groups that would not meet criteria for implantable cardioverter defibrillator (ICD) therapy. In conditions such as hypertrophic cardiomyopathy (HCM) there are clear risk scores that help define patients who are high risk for SCD and would benefit from ICD therapy. There are however many areas of uncertainty such as certain patients post myocardial infarction (MI). These patients are high risk for SCD but there is no clear tool for risk stratifying such patients.

AIM

To assess risk factors for sudden cardiac death in major cardiac disorders and to help select patients who might benefit from Wearable cardiac defibrillators (WCD).

METHODS

A literature search was performed looking for risk factors for SCD in patients post-MI, patients with left ventricular systolic dysfunction (LVSD), HCM, long QT syndrome (LQTS). There were 41 studies included and risk factors and the relative risks for SCD were compiled in table form.

RESULTS

We extracted data on relative risk for SCD of specific variables such as age, gender, ejection fraction. The greatest risk factors for SCD in post MI patients was the presence of diabetes [Hazard ratio (HR) 1.90-3.80], in patient with LVSD was ventricular tachycardia (Relative risk 3.50), in LQTS was a prolonged QTc (HR 36.53) and in patients with HCM was LVH greater than 20 mm (HR 3.10). A proportion of patients currently not suitable for ICD might benefit from a WCD

CONCLUSION

There is a very high risk of SCD post MI, in patients with LVSD, HCM and LQTS even in those who do not meet criteria for ICD implantation. These patients may be candidates for a WCD. The development of more sensitive risk calculators to predict SCD is necessary in these patients to help guide treatment.

Keywords: Sudden cardiac death; Wearable cardiac defibrillators; Myocardial infarction; Hypertrophic cardiomyopathy; Left ventricular systolic dysfunction

Core tip: This article looks at the risk factors for sudden cardiac death (SCD) in patients post myocardial infarction, patients with left ventricular systolic dysfunction, patients with hypertrophic cardiomyopathy, patients with long QT syndrome and the relative risk for sudden cardiac death of these risk factors. This is compared to the absolute risk of SCD for these conditions. We reviewed the recommendations from current guidelines and we outline where patients are at high risk for SCD but are not eligible for implantable cardioverter defibrillator implantation. The risk factors identified in this study can be used to select patients who may benefit from Wearable cardiac defibrillators therapy.