The incidence of implantable cardioverter defibrillator indications in patients admitted to all coronary care units in a single district

Abstract

Aims: Implantable cardioverter defibrillators (ICDs) have been shown to reduce all-cause mortality in groups of patients at high risk of ventricular arrhythmias. The true incidence of ICD indications is unknown but we hypothesize that it far exceeds the number actually implanted.

Methods: In a one month observational audit, we reviewed the clinical records of all 336 patients admitted to coronary care units serving a district with a population of 471,000, to determine the additional screening tests required in myocardial infarction (MI) survivors and the number of additional ICDs which would be implanted for the primary and secondary prevention indications recommended in UK National Institute for Clinical Excellence (NICE) guidance. A further analysis was performed to determine the effect of extending the primary prevention indications to include the selection criteria used in the second multicentre automatic defibrillator trial, MADIT II.

Results: Using NICE criteria, we found the incidence of ICD indications to be 98.4/10(6)/year. The addition of patients fulfilling MADIT II selection criteria for primary prevention would have increased this to 453/10(6)/year.

Conclusion: We conclude that the implementation of national guidance on the use of ICDs for arrhythmias will require the systematic screening of MI survivors, and would identify an incidence of ICD indications at least three times that anticipated by NICE, and eight times as many as were actually implanted in the UK in 2000. If the primary prevention indications were widened to include MADIT II selection criteria, the total would be nearer to 12 times that anticipated, and 47 times the number actually implanted.