Primary prevention of defibrillator implantation after myocardial infarction: clinical practice and compliance to guidelines

The purpose of this study is to investigate compliance to established guidelines regarding primary prevention with implantable cardioverter-defibrillator (ICD) in patients with left ventricular dysfunction after acute myocardial infarction (AMI) in a clinical setting.

A retrospective study of medical records from patients admitted to two hospitals in Stockholm during 2008–2009 with a diagnosis of AMI and who at discharge had a left ventricular ejection fraction ≤35%. An evaluation of follow-up and echocardiographic recordings was performed 1–3 months after AMI. A total of 2023 patients <80 years, with AMI discharged from hospital, were screened for left ventricular dysfunction defined as ejection fraction (EF) ≤35%. Altogether 187 patients were identified and an ICD was implanted in 25 (13%)  patients. In 52 (28%) patients, there were contraindications for ICD therapy. An improved EF at follow-up, making ICD treatment redundant, was observed in 48 (41%)  patients who underwent an ECHO at follow-up or later. Seventeen (9%) patients without an ICD died during follow-up and out of these five patients died from sudden cardiac death (SCD), they had no contraindication to ICD therapy. An inadequate follow-up according to guidelines was found in 59 (32%) patients.

The follow-up of post-myocardial infarction patients with left ventricular dysfunction according to guidelines was insufficient in this population and may have increased the risk for SCD. A significant proportion of patients experienced improved left ventricular function during short-term follow-up making preventive ICD treatment redundant.