Sudden cardiac death accounts for around 20 per cent of all deaths in Europe. Patients who have suffered a myocardial infarction are at particular risk. To date, their risk has primarily been assessed using left ventricular ejection fraction (LVEF), a measure of the pumping capacity of the left ventricle.
For patients with symptomatic heart failure following a myocardial infarction and an LVEF of 35 per cent or lower, the European heart failure guidelines have so far given prophylactic ICD implantation a Class I recommendation with evidence level A. The ICD (implantable cardioverter-defibrillator) detects dangerous cardiac arrhythmias and restores the heart to a normal rhythm by delivering electrical impulses.
However, the pivotal trials underlying this recommendation date back more than two decades. Many medications and treatment options now considered standard were not yet available at the time. Researchers led by Prof. Dr Gerhard Hindricks and Prof. Dr Nikolaos Dagres of the German Heart Center of Charité (DHZC) are therefore investigating within the international research project PROFID whether patients today still benefit from a prophylactically implanted ICD to the same extent following a myocardial infarction.
Methodology
The study draws on an exceptionally large body of data. For PROFID, individual-level data from more than 140,000 patients following myocardial infarction were pooled from 20 international datasets. The principal analysis of this dataset, published in 2024, showed that individual risk of sudden cardiac death cannot be reliably predicted.
The team has now published a new sub-analysis in the European Heart Journal and presented it at the ESC Congress 2026 in Munich. For this purpose, the researchers specifically analysed data from a subgroup of 32,214 patients with markedly reduced pump function, comparing overall mortality between patients with and without an implanted defibrillator over a period of 25 years. Depending on the period from which their data originated, patients were assigned to one of three study periods (1995–2004; 2005–2014; and 2015–2020).
The findings call the existing treatment approach into question: the survival benefit conferred by an ICD diminished progressively over the past two decades and could no longer be demonstrated in the most recently studied patient group. At the beginning of the study period, the researchers were still able to identify markedly lower mortality among patients with a defibrillator. This survival benefit remained stable for many years. In the most recent study period, from 2015 to 2020, however, this association could no longer be statistically substantiated.
Interpretation and Implications for Clinical Practice
"Our findings do not mean that ICD use in myocardial infarction patients with severely reduced pump function is generally no longer beneficial. Rather, they show that the current strategy of prophylactically implanting a defibrillator in these patients cannot be a one-size-fits-all solution. Each case must be considered individually," says Prof. Dr Gerhard Hindricks, Acting Director of the DHZC Department of Cardiology, Angiology and Intensive Care Medicine at Campus Charité Mitte, who leads the PROFID research project scientifically.
PROFID co-lead and senior author of the analysis, Prof. Dr Nikolaos Dagres, Senior Consultant at the DHZC Department of Cardiology, Campus Mitte, adds: "To determine precisely which myocardial infarction patients truly benefit from a defibrillator, and for which patients medication alone is sufficient, we need randomised data. This is exactly the question we are currently investigating in a clinical trial. The results could significantly change the treatment of patients following a myocardial infarction in future."
The randomised trial "PROFID EHRA", led by Charité, will study around 3,600 patients from 180 hospitals in 13 countries. It will compare whether optimal medical therapy alone is non-inferior to medical therapy combined with an additional ICD, in terms of overall mortality, in patients with reduced cardiac pump function following a myocardial infarction.
Through this research project, the scientists aim to help ensure that, in future, defibrillators are implanted specifically in those patients who genuinely benefit from them. This is intended to avoid unnecessary procedures while improving patient safety.
Advances in Patient Care
The analysis does not explicitly investigate the reasons why mortality rates among myocardial infarction patients with and without an ICD may have converged over time. One possible explanation, however, may lie in the considerable improvements in the treatment of myocardial infarction patients over recent decades. More effective medications and advances in catheter-based treatment of narrowed or occluded coronary arteries now help to improve patient prognosis. In addition, advances in the treatment of myocardial infarction may today result in less severe cardiac damage, which can lead to life-threatening arrhythmias.
Individual Patient Risk as a Basis
The researchers draw clear conclusions for risk stratification from their analysis. "Treatment planning must become more personalised in future. We need individualised approaches to make well-founded decisions about which myocardial infarction patients truly benefit from an ICD," says Dr Alireza Sepehri Shamloo, co-first author of the sub-analysis and researcher at the DHZC Department of Cardiology, Campus Mitte.
Toshinori Chiba, co-first author and researcher at the DHZC, adds: "Left ventricular ejection fraction alone is not a sufficient criterion for reliably assessing individual risk of sudden cardiac death. Many additional factors must be taken into account in this assessment."
The DHZC researcher presented the findings of the PROFID sub-analysis on 28 August at the annual congress of the European Society of Cardiology, the ESC Congress in Munich, as one of four finalists in the Young Investigator Award session. Among the numerous abstracts submitted for the Young Investigator Award sessions, his contribution on overall mortality in myocardial infarction patients with and without ICD therapy was ranked among the four best submissions in the field of arrhythmias.
Further information on the European research project PROFID ("Implementation of personalised risk prediction and prevention of sudden cardiac death after myocardial infarction") is available at: https://profid-project.eu/
Source: Press release DHZC
Original publication: Shamloo AS, Chiba T, Tijssen JGP; Mortality reduction with implanted defibrillator for primary prevention of sudden death after Myocardial Infarction: temporal trends in the PROFID study, European Heart Journal, 2026. doi:10.1093/eurheartj/ehag706
