Sudden cardiac death after myocardial infarction: individual participant data from pooled cohorts
Authors: Peek Niels , Hindricks Gerhard , Akbarov Artur , Tijssen Jan G P , Jenkins David A , Kapacee Zoher , Parkes Le Mai , van der Geest Rob J , Longato Enrico , Sprague Daniel , Taleb Youssef , Ong Marcus , Miller Christopher A , Shamloo Alireza Sepehri , Albert Christine , Barthel Petra , Boveda Serge , Braunschweig Frieder , Johansen Jens Brock , Cook Nancy , de Chillou Christian , Elders Petra , Faxén Jonas , Friede Tim , Fusini Laura , Gale Chris P , Jarkovsky Jiri , Jouven Xavier , Junttila Juhani , Kautzner Josef , Kiviniemi Antti , Kutyifa Valentina , Leclercq Christophe , Lee Daniel C , Leigh Jill , Lenarczyk Radosław , Leyva Francisco , Maeng Michael , Manca Andrea , Marijon Eloi , Marschall Ursula , Merino Jose Luis , Mont Lluis , Nielsen Jens Cosedis , Olsen Thomas , Pester Julie , Pontone Gianluca , Roca Ivo , Schmidt Georg , Schwartz Peter J , Sticherling Christian , Suleiman Mahmoud , Taborsky Milos , Tan Hanno L , Tfelt-Hansen Jacob , Thiele Holger , Tomaselli Gordon F , Verstraelen Tom , Vinayagamoorthy Manickavasagar , Olesen Kevin Kris Warnakula , Wilde Arthur , Willems Rik , Wu Katherine C , Zabel Markus , Martin Glen P , Dagres Nikolaos 
Published: October 2024

Abstract

Background and Aims
Risk stratification of sudden cardiac death after myocardial infarction and prevention by defibrillator rely on left ventricular ejection fraction (LVEF). Improved risk stratification across the whole LVEF range is required for decision-making on defibrillator implantation.

Methods
The analysis pooled 20 data sets with 140 204 post-myocardial infarction patients containing information on demographics, medical history, clinical characteristics, biomarkers, electrocardiography, echocardiography, and cardiac magnetic resonance imaging. Separate analyses were performed in patients (i) carrying a primary prevention cardioverter-defibrillator with LVEF ≤ 35% [implantable cardioverter-defibrillator (ICD) patients], (ii) without cardioverter-defibrillator with LVEF ≤ 35% (non-ICD patients ≤ 35%), and (iii) without cardioverter-defibrillator with LVEF &gt; 35% (non-ICD patients &gt;35%). Primary outcome was sudden cardiac death or, in defibrillator carriers, appropriate defibrillator therapy. Using a competing risk framework and systematic internal–external cross-validation, a model using LVEF only, a multivariable flexible parametric survival model, and a multivariable random forest survival model were developed and externally validated. Predictive performance was assessed by random effect meta-analysis.

Results
There were 1326 primary outcomes in 7543 ICD patients, 1193 in 25 058 non-ICD patients ≤35%, and 1567 in 107 603 non-ICD patients &gt;35% during mean follow-up of 30.0, 46.5, and 57.6 months, respectively. In these three subgroups, LVEF poorly predicted sudden cardiac death (c-statistics between 0.50 and 0.56). Considering additional parameters did not improve calibration and discrimination, and model generalizability was poor.

Conclusions
More accurate risk stratification for sudden cardiac death and identification of low-risk individuals with severely reduced LVEF or of high-risk individuals with preserved LVEF was not feasible, neither using LVEF nor using other predictors.